Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy (v.65, #3-4)

Theoretical studies on vibrational spectra of some mixed carbonyl-halide complexes of Osmium(II) by Zhao Jianying; Zhang Yu; Tang Guodong; Zhu Longgen (501-510).
The vibrational spectra of Os(CO)6 2+ and some of its mixed carbonyl-halide complexes, cis-Os(CO)2X4 2−, fac-Os(CO)3X3 and Os(CO)5X+ (X = F, Cl, Br and I), have been systematically investigated by ab initio RHF and density functional B3LYP methods with LanL2DZ and SDD basis sets. The calculated vibrational frequencies of complexes Os(CO)6 2+, cis-Os(CO)2X4 2− and fac-Os(CO)3X3 are evaluated via comparison with the experimental values. In infrared frequency region, the C–O stretching vibrational frequencies calculated at B3LYP level with two basis sets are in good agreement with the observed values with deviations less than 5%. In the far-infrared region, the B3LYP/SDD method achieved the best results with deviations less than 9% for Os–X stretching and less than 8% for Os–C stretching vibrational frequencies. The vibrational frequencies for Os(CO)5X+ that have not been experimentally reported were predicted.
Keywords: Vibrational frequencies; Ab initio RHF; Density functional B3LYP; Mixed carbonyl-halide complexes of Os(II);

Quantum chemical simulations of UV-absorption spectra in substituted bis-pyrazolopyridines were done. As a theoretical tool time dependent density functional theory (TDDFT) method with Vosko–Wilk–Nusair parameterisation was applied. Comparison of the theoretically simulated UV-absorption spectra with experimental data was performed. Crucial role of π-conjugated bonds within the backside phenyl rings is demonstrated. Physical insight of the several observed discrepancies between the calculations and experimental data is discussed. A comparison of the TDDFT and several semi-empirical approaches is given.
Keywords: UV-absorption spectra; Quantum chemical simulations;

Generalized two-dimensional (2D) fluorescence correlation spectroscopy has been used to resolve the fluorescence spectra of two tryptophan (Trp) residues in alcohol dehydrogenase and lysozyme. In each protein, one Trp residue is buried in a hydrophobic domain of the protein matrix and the other Trp residue is located at a hydrophilic domain close to the protein–water interface. Fluorescence quenching by iodide ion, a hydrophilic quencher, was employed as a perturbation to induce the intensity change in the spectra. The Trp residue which is located at the hydrophilic domain is effectively quenched by the quencher, while the Trp residue located at the hydrophobic domain is protected from the quenching. Therefore, the fluorescence of these two Trp residues have a different sensitivity to the quenching, showing a different response to the concentration of the quencher. Fluorescence spectra of the two Trp residues in alcohol dehydrogenase, which are heavily overlapped in conventional one-dimensional spectra, have been successfully resolved by the 2D correlation technique. From the asynchronous correlation map, it was revealed that the quenching of Trp located at the hydrophobic part was brought about after that of Trp located at the hydrophilic part. In contrast, the fluorescence spectra of the two Trp residues could not be resolved after the alcohol dehydrogenase was denatured with guanidine hydrochloride. These results are consistent with the well-known structure of alcohol dehydrogenase. Furthermore, it was elucidated that the present 2D analysis is not interfered by Raman bands of the solvent, which sometimes bring difficulty into the conventional fluorescence analysis. Fluorescence spectra of the Trp residues in lysozyme could not be resolved by the 2D correlation technique. The differences between the two proteins are attributed to the fact that the Trp residue in the hydrophobic site of lysozyme is not sufficiently protected from the quenching.
Keywords: Fluorescence; Tryptophan; Proteins; Two-dimensional correlation spectroscopy; Quenching;

New route to the synthesis of bis{N-(2-aminoethyl)salicylaldiminato}chromium(III) chloride monohydrate by Susobhan Biswas; Saikat Sarkar; Kamalendu Dey; Bimal Jana; Tarakdas Basu; Glenn P.A. Yap; Kevin Kreisel (523-528).
The reaction of [Cr(urea)6]Cl3·3H2O with H2salen (H2salen =  N,N -ethylenebis(salicylaldimine) in water–methanol mixture (40:60 v/v) under reflux yielded the complex bis{N-(2-aminoethyl)salicylaldiminato}chromium(III) chloride monohydrate, [Cr(aesaldmn)2]Cl·H2O. The complex was characterized by elemental analysis, molar conductance, magnetic susceptibility, spectroscopic (UV–vis and IR) data and X-ray diffraction studies. The new ligand, N-(2-aminoethyl)salicylaldimine, Haesaldmn, possibly resulted from the hydrolytic cleavage of one end of the H2salen ligand during reflux. Binding of this chromium(III) complex to CT DNA has been studied using UV–vis spectroscopy with an apparent binding constant of 2.68 × 103  M−1. It shows that the binding mode is electrostatic while the emission of ethidium bromide to CT DNA in the absence and in the presence of the complex show that it binds DNA with partial intercalation.
Keywords: Absorption spectroscopy; Hydrolytic cleavage; Crystal structure; DNA binding;

Raman spectroscopy of uranyl rare earth carbonate kamotoite-(Y) by Ray L. Frost; Matt L. Weier; Jiří Čejka; Godwin A. Ayoko (529-534).
Raman spectroscopy at 298 and 77 K has been used to study the mineral kamotoite-(Y), a uranyl rare earth carbonate mineral of formula Y2(UO2)4(CO3)3(OH)8·10–11H2O. The mineral is characterised by two Raman bands at 1130.9 and 1124.6 cm−1 assigned to the ν 1 symmetric stretching mode of the (CO3)2− units, while those at 1170.4 and 862.3 cm−1 (77 K) to the δU–OH bending vibrations. The assignment of the two bands at 814.7 and 809.6 cm−1 is difficult because of the potential overlap between the symmetric stretching modes of the (UO2)2+ units and the ν 2 bending modes of the (CO3)2− units. Only a single band is observed in the 77 K spectrum at 811.6 cm−1. One possible assignment is that the band at 814.7 cm−1 is attributable to the ν 1 symmetric stretching mode of the (UO2)2+ units and the second band at 809.6 cm−1 is due to the ν 2 bending modes of the (CO3)2− units. Bands observed at 584 and 547.3 cm−1 are attributed to water librational modes. An intense band at 417.7 cm−1 resolved into two components at 422.0 and 416.6 cm−1 in the 77 K spectrum is assigned to an Y2O2 stretching vibration. Bands at 336.3, 286.4 and 231.6 cm−1 are assigned to the ν 2 (UO2)2+ bending modes. U–O bond lengths in uranyl are calculated from the wavenumbers of the uranyl symmetric stretching vibrations. The presence of symmetrically distinct uranyl and carbonate units in the crystal structure of kamotoite-(Y) is assumed. Hydrogen-bonding network related to the presence of water molecules and hydroxyls is shortly discussed.
Keywords: Kamotoite; Mineral; Uranyl; Rare earth elements; Carbonate; Raman spectroscopy;

The molar transition energy (E T) polarity values for the dye 4-[4-(dimethylamino)styryl]-1-methylpyridinium iodide were collected in binary mixtures comprising a hydrogen-bond accepting (HBA) solvent (acetone, acetonitrile, dimethyl sulfoxide (DMSO), and N,N-dimethylformamide (DMF)) and a hydrogen-bond donating (HBD) solvent (water, methanol, ethanol, propan-2-ol, and butan-1-ol). Data referring to mixtures of water with alcohols were also analyzed. These data were used in the study of the preferential solvation of the probe, in terms of both solute–solvent and solvent–solvent interactions. These latter interactions are of importance in explaining the synergistic behavior observed for many mixed solvent systems. All data were successfully fitted to a model based on solvent-exchange equilibria. The E T values of the dye dissolved in the solvents show that the position of the solvatochromic absorption band of the dye is dependent on the medium polarity. The solvation of the dye in HBA solvents occurs with a very important contribution from ion–dipole interactions. In HBD solvents, the hydrogen bonding between the dimethylamino group in the dye and the OH group in the solvent plays an important role in the solvation of the dye. The interaction of the hydroxylic solvent with the other component in the mixture can lead to the formation of hydrogen-bonded complexes, which solvate the dye using a lower polar moiety, i.e. alkyl groups in the solvents. The dye has a hydrophobic nature and a dimethylamino group with a minor capability for hydrogen bonding with the medium in comparison with the phenolate group present in Reichardt's pyridiniophenolate. Thus, the probe is able to detect solvent–solvent interactions, which are implicit to the observed synergistic behavior.
Keywords: Preferential solvation; Binary mixtures; Merocyanines; Solvent effects; Solvent–solvent interactions; Solute–solvent interactions;

Fluorescence enhancement of yttrium(III)–rutin by nucleic acids in the presence of cetyltrimethylammonium bromide by Xia Wu; Changying Guo; Fei Wang; Jinghe Yang; Dehuan Ran; Jinhua Zheng; Jinbo Wu (543-548).
It is found that nucleic acids can enhance the fluorescence intensity of yttrium(III) (Y3+)–rutin in presence of cetyltrimethylammonium bromide (CTMAB) system. In hexamethylenetetramine (HMTA)–HCl buffer, the maximum enhanced fluorescence is produced, with maximum excitation and emission wavelengths at 452 and 520 nm, respectively. Based on this, a new fluorimetric method of determination of nucleic acids is proposed. Under optimum conditions, the enhanced fluorescence intensity is proportion to the concentration of nucleic acids in the range of 1.0 × 10−7 to 1.0 × 10−5  g/ml for fish sperm DNA (fsDNA), 1.0 × 10−7 to 4.6 × 10−6  g/ml for yeast RNA (yRNA), their detection limits (S/N = 3) are 7.5 × 10−8, 8.0 × 10−8  g/ml, respectively. The interaction mechanism is also studied.
Keywords: Fluorescence enhancement; Y3+–rutin–CTMAB complex; Nucleic acids;

Herein we describe the synthesis and spectroscopic (infrared and UV–vis) analysis of [CuII(dohpn)(L)] n+ (dohpn = imineoximic tetraazamacrocyclic ligand 2,3,9,10-tetramethyl-1,4,8,11-tetraazaundecane-1,3,8,10-tetraen-11-ol-1-olate) and L = SCN, I, Cl (n  = 0) and 4-aminopyridine (ampy), 4,4′-bipyridine (bipy), imidazole (im), 2-aminopyrazine (ampz) and water (n  = 1+). The following order of the Jahn-Teller stabilization energy (cm−1) was observed: I(6452) < Cl(6477) < NCS(6494) < ampy(6562) < im(6614) < bipy(6685) < ampz(6739) < H2O(7813) and the energy of the crystal field transition was correlated with the tetragonal distortion in the structures.
Keywords: Copper(II); Iminooximic macrocycle; Jahn-Teller effect;

Raman and thermo-Raman spectroscopy have been applied to study the natural hydrotalcite manasseite Mg6Al2(OH)16(CO3)·4H2O. Hydrogen bond distances calculated using a Libowitzky-type empirical function varied between 2.61 and 3.00 Å. Stronger hydrogen bonds were formed by water units as compared to the hydroxyl units. Thermo-Raman spectroscopy enabled the identification of bands attributed to the hydroxyl units. Two Raman bands at 1062 and 1058 cm−1 are assigned to symmetric stretching modes of the carbonate anion. Thermal treatment shifts these bands to higher wavenumbers indicating a change in the carbonate bonding.
Keywords: Manasseite; Sjögrenite; Stitchtite; Iowaite; Desautelsite; Takovite; Hydrotalcite; Raman spectroscopy;

The infrared and Raman spectra of KCF3SO2 were obtained and the observed spectral features assigned to the expected normal modes of vibration. Besides, the vibrational properties of the CF3SO2 and CF3SeO2 related anions were studied by means of density functional theory (DFT) techniques. After obtaining the optimized geometrical parameters and conformations, the vibrational wavenumbers and the associated force constants were calculated. The original force fields in cartesian coordinates were transformed to local symmetry coordinates and subsequently scaled to reproduce the experimental wavenumbers. Some trends observed in the force constants of the studied species and of the related CF3SO3 anion could be explained by the differences in geometrical parameters.
Keywords: Trifluoromethylsulfinate; Trifluoromethylseleniate; Force constants; Structure; DFT calculation;

Fluoride ion detection by 8-hydroxyquinoline–Zr(IV)–EDTA complex by R. Sai Sathish; U. Sujith; G. Nageswara Rao; C. Janardhana (565-570).
A simple fluorescent detection based on the ligand exchange mechanism is proposed for the fluoride ion in aqueous media. This procedure is based on the exchange of 8-hydroxyquinoline (oxine) coordinated to Zr(IV) by fluoride ion without interference from other common anions. The ternary complex of oxine with [Zr(H2O)2EDTA]·2H2O formed by replacing two water molecules in aqueous solution provides a sensitive signalling system for fluoride ion in the concentration range from 6 × 10−7  M to 8 × 10−4  M. The green fluorescence (λ max  = 532 nm) exhibited by the complex upon excitation at 247 nm decreases in intensity with fluoride addition with a detection limit of 12 ppb. The complexation reaction between oxine and Zr(IV)–EDTA and the ligand exchange reaction with fluoride ion has been investigated by UV–vis and fluorescence spectroscopies combined with the PM3 semi-empirical quantum chemical calculations. Job's method of continuous variation and the molar ratio method ascertain a 1:1 stoichiometry composition of the chelate in aqueous media.
Keywords: 8-Hydroxyquinoline; [Zr(H2O)2EDTA]·2H2O; Complexation; Ligand exchange; Fluoride sensing; PM3;

A Raman spectroscopic study of the uranyl tellurite mineral schmitterite by Ray L. Frost; Jiří Čejka; Matt Weier; Godwin A. Ayoko (571-574).
Raman spectra of schmitterite measured at 298 and 77 K are presented and discussed in detail and in part in comparison with published IR spectrum of synthetic schmitterite. U―O bond lengths in uranyls, calculated with the empirical relations R U–O  =  f[ν 1(UO2)2+] Å and R U–O  =  f[ν 3(UO2)2+] Å, are close to those inferred from the X-ray single crystal structure of synthetic schmitterite and agree also with the data for other natural and synthetic uranyl tellurites.
Keywords: Selenite; Tellurite; Raman spectroscopy; U―O bond length; Uranyl;

The quantum mechanical force fields of 3,3-dimethyl-1,2-bis-(tert-butyl)cyclopropene (I), 3,3-dimethyl-1,2-bis-(trimethylsilyl)cyclopropene (II), 3,3-dimethyl-1,2-bis-(trimethylgermyl)cyclopropene (III), and 3,3-dimethyl-1,2-bis-(trimethylstannyl)cyclopropene (IV) were calculated at the HF/3-21G*//HF/3-21G* level. The scale factors which were optimized previously for the HF/3-21G*//HF/3-21G* quantum mechanical force field of 3,3-dimethyl-1-(trimethylsilyl)cyclopropene were used for correction of the force fields of these molecules. Good agreement between the frequencies calculated from these scaled force fields and the well-analyzed and assigned experimental frequencies of II and III suggests the transferability of these scale factors and the possibility of the spectroscopically accurate prediction of the vibrational spectrum of IV. Some regularities in the changes of the vibrational frequencies were found for this molecular series.
Keywords: 3,3-Dimethyl-1,2-bis-(trimethylstannyl)cyclopropene; Experimental IR vibrational spectrum; Scaled quantum mechanical force field; Vibrational analysis;

Polyvinyl alcohol (PVA) matrix was used to confine the particle size of ZnSe nanocrystallites as well as the variation of zinc (Zn) to selenium (Se) ion ratio which showed a remarkable decrease on the particle size as this ratio increased. The particle size decrease was monitored from the UV–vis absorption measurement as well as photoluminescence which suffered a blue shift with particle size decrease. The particle size was characterized with the aid of X-ray diffraction (XRD). The Raman spectra showed that, as the particle size increases, the peak position of the line centers (LO) mode were found to be red shifted from 239 to 234 cm−1, accompanied by an increase in the full-width at half-maximum (FWHM). The electrical measurements and FT-IR spectra (overtone and normal) band vibration were used to study the effect of ZnSe NPs size on the PVA matrix.
Keywords: ZnSe NPs; Raman spectra; IR spectra; PVA;

The paper reports on the spectral photophysical characteristics of two new fluorescent PAMAM dendrimers of zero and second generation decoreted with 1,8-naphthalimide units, designed for ionic detection. The dendrimers were studied by 1H NMR, 13C NMR, FT-IR spectroscopy and elemental analysis. Their ability to detect ions has been evaluated in acetonitrile by monitoring the quenching of the fluoresence intensity. Different ions have been tested: Zn2+, Co2+, Ni2+, Cu2+ and Fe3+ for the purpose. The results have shown clearly that only Zn2+ could be efficiently detected using the dendrimer of second generation. In addition, it has been shown that for both dendrimers in a acetonitrile–water solution, the fluoresence intensity is pH dependant, hence could find application as a detector of harmful pH changes in the environment.
Keywords: PAMAM dendrimer; Sensor; 1,8-Naphthalimide; Absorbance; Fluorescence; FT-IR spectroscopy;

Trinuclear lanthanide complexes of the formula [Ln3(PPDA)(NO3)6(H2O)2]·NO3·2H2O where Ln = La(III), Pr(III), Sm(III), Nd(III), Eu(III) Gd(III) Tb(III), Dy(III) and Y(III); H2PPDA =  N,N′-bis(2-pyridinyl)-2,6-pyridinedicarboxamide, have been isolated. The complexes were characterized by elemental analyses, conductivity measurements, magnetic susceptibility measurements and spectral (IR, NMR, UV–vis, fluorescence, FAB and EPR) and thermal studies.
Keywords: Lanthanide complexes; N,N′-Bis(2–pyridinyl)-2,6-pyridinedicarboxamide metal complexes; Compartmental ligand; Spectral studies; NMR spectroscopy; Fluorescence spectroscopy;

Intramolecular hydrogen bond, molecular structure and vibrational assignment of tetra-acetylethane by Heidar Raissi; Alireza Nowroozi; Reza Mohammdi; Mohammad Hakimi (605-615).
The intramolecular hydrogen bond, molecular structure and vibrational frequencies of tetra-acetylethane have been investigated by means of high-level density functional theory (DFT) methods with most popular basis sets. Fourier transform infrared and Fourier transform Raman spectra of this compound and its deuterated analogue were recorded in the regions 400–4000 cm−1 and 40–4000 cm−1, respectively. The calculated geometrical parameters of tetra-acetylethane were compared to the experimental results of this compound and its parent molecule (acetylacetone), obtained from X-ray diffraction. The O···O distance in tetra-acetylethane, about 2.424 Å, suggests that the hydrogen bond in this compound is stronger than acetylacetone. This conclusion is well supported by the NMR proton chemical shifts and O–H stretching mode at 2626 cm−1. Furthermore, the calculated hydrogen bond energy in the title compound is 17.22 kcal/mol, which is greater than the acetylacetone value. On the other hand, the results of theoretical calculations show that the bulky substitution in α-position of acetylacetone results in an increase of the conjugation of π electrons in the chelate ring. Finally, we applied the atoms in molecules (AIM) theory and natural bond orbital method (NBO) for detail analyzing the hydrogen bond in tetra-acetylethane and acetylacetone. These results are in agreement with the vibrational spectra interpretation and quantum chemical calculation results. Also, the conformations of methyl groups with respect to the plane of the molecule and with respect to each other were investigated.
Keywords: Intramolecular hydrogen bond; Tetra-acetylethane; Vibrational spectra; Density functional theory; AIM and NBO;

To understand the substituting effects of organic ligands on the reaction equilibrium, the interactions between diperoxovanadate complex [OV(O2)2(H2O)] and a series of picoline-like ligands in solution were explored using 1D multinuclear (1H, 13C, and 51V) magnetic resonance, 2D diffusion ordered spectroscopy (DOSY), and variable temperature NMR in 0.15 mol/l NaCl ionic medium for mimicking the physiological conditions. The order of reactive capability of the picoline-like ligands with [OV(O2)2(H2O)] is found to be picolinamide >  N-methylpicolinamide > methyl picolinate > ethyl picolinate ≈ propyl picoliniate > isopropyl picolinate. The substituting group influences the reactivity by either steric effect or electron-donating effect. Competitive coordination interactions result in a series of new seven-coordinated peroxovanadate species [OV(O2)2L] (L = picoline-like ligands). Their coordination ways were confirmed by density functional calculations.
Keywords: Diperoxovanadate; Picoline-like ligand; Interactions; NMR; Density functional;

The mineral allactite [Mn7(AsO4)2(OH)8] is a basic manganese arsenate which is highly pleochroic. The use of the 633 nm excitation line enables quality spectra of to be obtained irrespective of the crystal orientation. The mineral is characterised by a set of sharp bands in the 770–885 cm−1 region. Intense and sharp Raman bands are observed at 883, 858, 834, 827, 808 and 779 cm−1. Collecting the spectral data at 77 K enabled better band separation with narrower bandwidths. The observation of multiple AsO4 stretching bands indicates the non-equivalence of the arsenate anions in the allactite structure. In comparison the infrared spectrum shows a broad spectral profile with a series of difficult to define overlapping bands. The low wavenumber region sets of bands which are assigned to the ν 2 modes (361 and 359 cm−1), the ν 4 modes (471, 452 and 422 cm−1), AsO stretching vibrations at 331 and 324 cm−1, and bands at 289 and 271 cm−1 which may be ascribed to MnO stretching modes. The observation of multiple bands shows the loss of symmetry of the AsO4 units and the non-equivalence of these units in the allactite structure. The study shows that highly pleochroic minerals can be studied by Raman spectroscopy.
Keywords: Allactite; Arsenate; Flinkite; Retzian(La,Ce,Nd); Raman spectroscopy;

Formation of complex films with water-soluble CTAB molecules by S. Biswas; S.A. Hussain; S. Deb; R.K. Nath; D. Bhattacharjee (628-632).
This communication reports the formation of complex Langmuir monolayer at the air–water interface with the water-soluble N-cetyl N,N,N-trimethyl ammonium bromide (CTAB) molecules when interacted with the stearic acid (SA) molecules. The reaction kinetics of the formation of the CTAB–SA complex was monitored by observing the surface pressure versus time graph. Multilayered LB films of this complex doped with Congo red was successfully formed onto a quartz substrate. UV–Vis absorption and steady-state fluorescence spectroscopic characteristics of this doped LB films confirms the successful incorporation of Congo red molecules in to the CTAB–SA complex films.
Keywords: Water-soluble; Reaction kinetics; Langmuir Films; UV–Vis absorption spectroscopy; Fluorescence spectroscopy;

Fluoride-selective colorimetric sensor based on thiourea binding site and anthraquinone reporter by Fang-ying Wu; Mei-hua Hu; Yu-mei Wu; Xiao-fang Tan; Yong-qiang Zhao; Zhao-jun Ji (633-637).
A structurally simple colorimetric sensor, N-4-nitrobenzene-N′-1′-anthraquinone-thiourea (1), for anions was synthesized and characterized by 1H NMR, ESI mass and IR methods. In acetonitrile, the addition of F changed 1 solution from colorless to yellow. In the presence of other anions such as CH3CO2 , H2PO4 , HSO4 and Cl, however, the absorption spectrum of 1 was slightly red shifted with no obvious color changes observed. The association constants of anionic complexes followed the order of F  ≫ CH3CO2  > H2PO4  > HSO4  > Cl  > Br, which was different from the order of anion basicity. AM1 calculation results indicated that the most stable configuration of 1 existed in the Z–E-conformation with a six-membered ring via intramolecular hydrogen bond. This made thiourea moiety of 1 in an unfavorable conformation to bond with oxygen-anionic substrates such as CH3CO2 and H2PO4 , thus leading to a high selectivity and sensitivity for the detection of F.
Keywords: Anion recognition; Colorimetric assay; N-4-nitrobenzene-N′-1′-anthraquinone-thiourea;

This paper presents an analysis of the infrared vibrational intensities found for C6H6, C6D6 and C6H5D in the liquid phase, motivated in part by the quite marked intensity differences between the fundamentals of C6H6 and C6D6 in the liquid, and between corresponding vibrations in the liquid and gas phases. The analysis is carried out under the harmonic approximation and results from a determination of the force field for liquid C6H6, C6D6 and C6H5D. The force constants for the liquid-phase are presented and compared to those in the literature for the gas-phase. Previously reported experimental intensities are used along with the eigenvectors of the force field analysis to determine the dipole moment derivatives with respect to symmetry and internal coordinates. The dipole moment derivatives with respect to internal coordinates obtained are ∂μ/∂s=  0.38 ± 0.02 Debye Å−1, ∂μ/∂t=  0.24 ± 0.01, ∂μ/∂β=  0.26 ± 0.01, and ∂μ/∂γ=  0.64 ± 0.03 Debye Å−1. There is very little difference between the dipole moment derivatives with respect to internal coordinates obtained from non-linear least squares fitting of the two D6h isotopomers and those obtained from non-linear least squares fitting of the three isotopomers. The results show that there is significant intensity sharing in the CH stretch region of C6H5D between the fundamental and combination bands.
Keywords: Infrared intensities; Liquid; Benzene; Dipole moment derivatives; Force field;

This paper presents a comparison of the dipole moment derivatives with respect to internal coordinates in the liquid and gas phases for benzene-h6, benzene-d6 and benzene-d1. The literature values of the integrated intensities of the infrared active fundamentals of the three gaseous isotopomers are used to determine the dipole moment derivatives with respect to internal coordinates, using the methods described in the previous paper for the liquid phase. As was found for the liquid phase in the previous paper, there is uncertainty surrounding the intensities of the individual CH stretching fundamentals of benzene-d1 due to intensity sharing with active combinations. The magnitudes of the dipole moment derivatives with respect to internal coordinates in the gas phase are ∂μ/∂s  = 0.50 ± 0.03 D Å−1, ∂μ/∂t  = 0.28 ± 0.03, ∂μ/∂β  = 0.24 ± 0.01, and ∂μ/∂γ  = 0.65 ± 0.02 D Å−1, where s, t, β and γ are the CH stretching, and CC stretching, the HCC bending and the HCCC torsion displacements, respectively. The experimental intensities are different for the three isotopomers in the liquid and gas phases, and the calculations show that these differences are mainly due to a difference between the CH stretch dipole moment derivatives in the two phases. This difference was related qualitatively to the intermolecular interaction of the H with the π-cloud of the nearest neighbour creating a pseudo-hydrogen bond.
Keywords: Infrared intensities; Liquid; Gas; Benzene; Dipole moment derivatives; Force field;

The absorption spectra of the electron donor–acceptor complexes of [60]fullerene with five different aromatic hydrocarbon (AH) molecules containing flexible phenyl substituents have been investigated in toluene medium. An absorption band due to charge transfer (CT) transition is observed in each case in the visible region. The experimental CT transition energies are well correlated with the vertical ionization potentials of the AHs studied (through Mulliken's equation) from which we extract degrees of charge transfer, oscillator and transition dipole strengths of the CT complexes. The degrees of CT in the ground state of the complexes have been found to be very low (0.49–0.55%). The formation constants (K) for the complexes of [60]fullerene with the aromatic hydrocarbons have been determined by UV–vis spectroscopy. Both K values and PM3 calculations on [60]fullerene/AH complexes reveal that nature of substitution in the donor moiety as well as steric compatibility with the acceptor molecule govern the process of EDA complex formation.
Keywords: [60]Fullerene; Aromatic hydrocarbons; CT bands; Formation constants;

The optical absorption studies of sodium copper chlorophyllin thin films (SCC), prepared by spray pyrolysis, in the UV–vis–NIR region was reported for the first time. Several new discrete transitions are observed in the UV–vis region of the spectra in addition to a strong continuum component in the IR region. The spectra of the infrared absorption allow characterization of vibration modes for the powder and thin films of SCC. The absorption spectrum recorded in the UV–vis region showed different absorption bands, namely the Soret (B) in the region 340–450 nm and Q-band in the region 600–700 nm and other band labeled N in the 240–320 region. Some important spectral parameters namely optical absorption coefficient (α), molar extinction coefficient (ɛ molar), oscillator strength (f), electric dipole strength (q 2) and absorption half bandwidth (Δλ) of the principle optical transitions were evaluated. The analysis of the absorption coefficient in the absorption region revealed direct transitions and the energy gap was estimated as 1.63 eV. Discussion of the obtained results and their comparison with the previous published data are also given.
Keywords: Optical absorption; Sodium copper chlorophyllin; Thin film;

Solvent effects on the absorption and fluorescence spectra of coumarins 6 and 7 molecules: Determination of ground and excited state dipole moment by U.S. Raikar; C.G. Renuka; Y.F Nadaf; B.G. Mulimani; A.M. Karguppikar; M.K. Soudagar (673-677).
Absorption and fluorescence emission spectra of coumarins 6 and 7 were recorded in solvents with different solvent parameters, viz., dielectric constant ɛ and refractive index n. The fluorescence lifetime of these dyes were measured in butanol at higher values of viscosity over temperature. Experimental ground and excited state dipole moments are determined by means of solvatochromic shift method and also the excited state dipole moments are determined in combination with ground state dipole moments. It was determined that dipole moments of the excited state were higher than those of the ground state in both the molecules.
Keywords: Solventeffect; Fluorescence lifetime; Dipole moments; Coumarin dyes; Solvatochromic shift;

Synthesis, characterization, electro chemistry, catalytic and biological activities of ruthenium(III) complexes with bidentate N, O/S donor ligands by K.P. Balasubramanian; K. Parameswari; V. Chinnusamy; R. Prabhakaran; K. Natarajan (678-683).
New hexa-coordinated ruthenium(III) complexes of the type [RuX2(EPh3)2(L)] (E = P or As; X = Cl or Br; L = monobasic bidentate Schiff base derived from the condensation of benzhydrazide with furfuraldehyde, 2-acetylfuran and 2-acetylthiophene) have been synthesized from the equimolar amounts of [RuX3(EPh3)3] or [RuBr3(PPh3)2(MeOH)] and Schiff bases in benzene. The new complexes have been characterized by analytical, spectral (IR, electronic and EPR), magnetic moment, and cyclic voltammetry. An octahedral structure has been tentatively proposed. All the complexes have exhibited catalytic activity for the oxidation of benzyl alcohol, cyclohexanol and cinnamylalcohol in the presence of N-methylmorpholine-N-oxide as co-oxidant. All the new complexes were found to be active against the bacteria such as E. coli, Pseudomonas, Salmonella typhi and Staphylococcus aureus. The activity was compared with standard Streptomycin.
Keywords: Ruthenium(III) complexes; EPR; Cyclic voltammetry; Catalytic activity; Antibacterial studies;

Characterization of clinohumite by selected spectroscopic methods by S. Lakshmi Reddy; N.C. Gangi Reddy; G. Siva Reddy; B. Jagannatha Reddy; Ray L. Frost (684-688).
Clinohumite, a humite group mineral, originated from Pamir Mountains, USSR, is used in the present work. Optical absorption, electron paramagnetic resonance (EPR), near infrared (NIR) and Mössbauer techniques are used in the characterization of the mineral sample. The optical absorption spectrum indicates that Fe(II) impurity is present in two sites with distorted octahedral structure. NIR results are attributed to water fundamentals. EPR studies on powder sample confirm the presence of Mn(II) in three different sites and also an iron impurity. Mössbauer studies confirm the presence of iron impurity in two different sites.
Keywords: Humite; Clinohumite; Electron paramagnetic resonance; Near infrared spectroscopy; Mössbauer spectroscopy; Optical absorption; Electron paramagnetic resonance;

Synthesis characterization and biological study of diorganotin(IV) complexes of monomethyl phthalate by Wajid Rehman; Musa Kaleem Baloch; Amin Badshah; Saqib Ali (689-694).
The synthesis and characterization of new coordination compounds of some organotin(IV) chlorides with monomethyl phthalate is reported; the ligand molecules appear to be bound to the tin atom through carbonyl oxygen atoms. Their structures have been characterized by elemental analyses, molar conductance, and bonding in these complexes is discussed in terms of their IR, 1H, 13C, 119Sn NMR and 119mSn Mössbauer spectral studies. The spectroscopic results obtained are in full agreement with the proposed 2:1 stoichiometry. The complexes soluble in DMSO have been screened against a wide spectrum of bacteria and the results obtained are quite promising. The LD50 values have also been determined in the albino rats. Some of the complexes also exhibit high anti-inflammatory activity.
Keywords: Organotin(IV); Monomethyl phthalate; Anti-inflammatory; Acute toxic; Cytostatic;

UV–visible spectroscopic study of the salicyladehyde benzoylhydrazone and its cobalt complexes by Yi-Heng Lu; Yu-Wei Lu; Cheng-Li Wu; Qun Shao; Xiao-Ling Chen; Rosa Ngo Biboum Bimbong (695-701).
Salicyladehyde benzoylhydrazone (SBH) has three groups suitable for forming coordination bond with transition metal. The UV–vis absorption spectra of SBH and its Co(II) complexes in various media were studied by using the deconvolution method. It is found that the structure of complex in solution is different from those in solid crystals. The nature of complexes in solution depends on acidity of the phenolic proton of SBH and on the medium. In neutral or slightly acid medium, the SBH is a non-charged bidentate ligand. And the “free” hydroxyl group on the SBH molecule makes it possible to form hydrogen bonds in solution. In basic medium, the SBH is a mono, negatively charged tridentates ligand.
Keywords: Gaussian deconvolution; UV–vis spectra; Hydrogen bond; Ligand; Salicyladehyde benzoylhydrazone;

Optical parameters and upconversion fluorescence in Tm3+/Yb3+-doped alkali-barium-bismuth-tellurite glasses by Hai Lin; Ke Liu; Lin Lin; Yanyan Hou; Dianlai Yang; Tiecheng Ma; Edwin Yun Bun Pun; Qingda An; Jiayou Yu; Setsuhisa Tanabe (702-707).
Tm3+/Yb3+-doped alkali-barium-bismuth-tellurite (LKBBT) glasses have been fabricated and characterized. Density, refractive index, optical absorption, absorption and emission cross-sections of Yb3+, Judd–Ofelt parameters and spontaneous transition probabilities of Tm3+ have been measured and calculated, respectively. Intense blue three-photon upconversion fluorescence and near-infrared two-photon upconversion fluorescence were investigated under the excitation of a 980 nm diode laser at room temperature. Wide infrared transmission window, high refractive index and strong blue three-photon upconversion emission of Tm3+ indicate that Tm3+/Yb3+ co-doped LKBBT glasses are promising upconversion optical and laser materials.
Keywords: Alkali-barium-bismuth-tellurite glasses; Rare-earth ions; Optical parameters; Upconversion;

Near-ultraviolet chemiluminescence from the reaction of ammonia with hypobromite in aqueous solution by Paul S. Francis; Jacqui L. Adcock; Neil W. Barnett (708-710).
The chemiluminescence arising from the oxidation of ammonium chloride by sodium hypobromite in aqueous alkaline solution includes a series of peaks in the near-ultraviolet, which is not commonly observed in liquid-phase chemiluminescence. The dominant peak in that region has an intensity maximum at 292 nm and smaller peaks are observed at 313, 334 and 356 nm. The emitted photons are of similar energy to the Vergard–Kaplan transition of molecular nitrogen, a major product of this reaction. However, the spectral distribution is different to that of previously reported gas-phase chemiluminescence attributed to the Vergard–Kaplan transition.
Keywords: Near-ultraviolet chemiluminescence; Ammonia; Hypohalites; Molecular nitrogen;

Conformation study of HA(306–318) antigenic peptide of the haemagglutinin influenza virus protein by A. Bertrand; R.M. Brito; A.J.P. Alix; J.M. Lancelin; R.A. Carvalho; C.F.G.C. Geraldes; F. Lakhdar-Ghazal (711-718).
Several HLA-DR alleles present the immunodominant HA(306–318) peptide of haemagglutinin of the influenza virus to T cells. NMR data of the peptide in various water solutions exclude any α-helix or turn conformations. Circular dichroism and Fourier transform infrared spectroscopies indicate an estimated β-extended structure in water of 31% and 28%, respectively, with spectra shape similar to the ones observed for β-sheet containing proteins. The H/D amide exchange suggests a stable length-dependent interchain hydrogen-bonding. The partially β-extended conformation of HA(306–318) in solution might be close to the one found in HA(306–318)–HLA-DR1 complex. These results suggest different interconverting extended conformations of HA(306–318), depending on the microenvironment of the solution medium. This flexibility emphasizes the ability of some peptides to fit more easily the binding site of several HLA-DR molecules. Similar results were obtained on the HIV P25(263–277) peptide which has been previously shown to be a good DR1 binder.From a vibrational point of view, infrared Amide I frequencies of secondary structures in peptides were ascertained.As previously demonstrated for proteins in solution, Fourier transform infrared and circular dichroism spectroscopies appear to be valuable tools for conformational properties of peptides. Their use may contribute to the detection of peptide conformation-binding relationship which has to be further tested by biochemical and biological studies.
Keywords: Influenza virus haemagglutinin peptide; HLA-DR epitope; Peptide conformation; FT-IR; NMR; CD; Solvent environment;

Three types of copper complexes as well as an oximate-bridged nickel complex with isonitrosoacetophenone 2-aminobenzoylhydrazone (H2L) have been prepared in ethanolic solution and characterized by elemental analyses, IR, 1H NMR, UV–vis and magnetic susceptibility measurement. IR spectra show the ligand coordinates as a neutral, monoanionic and dianionic O,N,N-tridentate acylhydrazoneoxime ligand depending reaction conditions and metal salts employed. The elemental analyses results, spectroscopic and magnetic data are consistent with the formation of mononuclear copper complexes and binuclear complexes with both copper and nickel. The effects of varying pH and solvent on the absorption behavior of both ligand and complexes have been investigated. The extraction ability of acylhydrazoneoxime ligand has been examined by the liquid–liquid extraction of selected transition metal [Cu2+, Ni2+, Co2+, Cr3+, Hg2+, Zn2+, Cd2+ and Mn2+] cations. The ligand shows strong binding ability toward copper(II) ion.
Keywords: Hydrazoneoxime ligands; Transition metal cations; Complexes; IR and electronic spectra; Solvent extraction;

Recalling the appropriate representation of electronic spectra by Gonzalo Angulo; Guenter Grampp; Arnulf Rosspeintner (727-731).
This paper presents a critical discussion on the representation of UV–vis–NIR light absorption and fluorescence emission spectra of polyatomic molecules in liquid solution. A general overview how to handle the experimental spectra in order to extract physical data from them is presented together with some simulations to show the errors that can arise from unfortunate manipulation.
Keywords: Absorption; Fluorescence; Transition dipole moment representation;

The present study is interested to develop a simple, rapid and accurate spectrophotometric method for determination of sodium flucloxacillin (fluc) in pure form and pharmaceutical formulations. The charge-transfer (CT) interactions between sodium flucloxacillin as electron donor and chloranilic acid (CLA), dichloroquinone 4-chloroimide (DCQ), 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) and 7,7,8,8 tetracyano-p-quinodimethane (TCNQ), as π-electron acceptors have been investigated spectrophotometrically. Different variables affecting the reaction were studied and optimized. Under the optimum conditions, linear relationships with good correlation coefficients (0.9979–0.9995) were found between the absorbance and the concentration of the drug in the range 16–880 μg ml−1. The proposed methods were applied successfully to the determination of the examined drug either in pure or pharmaceutical dosage forms with good accuracy and precision. The formation of the CT-complexes and the sites of interaction were confirmed by elemental analysis CHN, UV–vis, IR, 1H NMR and mass spectra techniques. Based on Job's method of continuous variation plots, the obtained results indicate the formation of 1:1 charge-transfer complexes with the general formula [(fluc)(acceptor)]. Statistical analysis of the obtained results showed no significant difference between the proposed method and official method.
Keywords: Spectrophotometry; Flucloxacillin; CT-complexes; π-Acceptors;

Electron paramagnetic resonance of VO2+ doped sodium hydrogen oxalate monohydrate (NaHC2O4·H2O) single crystals and powders are examined at room temperature. Single crystal rotations in each of the three mutually orthogonal crystalline planes namely ac*, b*c* and ab* indicate four different VO2+ complexes with intensity ratios of 4:2:1:1. It is found from the EPR analysis that the Na+ ions are replaced with the substitutional magnetically inequivalent VO2+ ions. The powder spectrum also clearly indicates four different VO2+ complexes, confirming the single crystal analysis. Crystalline field around the VO2+ ion is nearly axial. The optical absorption spectrum show two bands centered at 15 408 and 12 453 cm−1. Spin Hamiltonian parameters and molecular orbital coefficients are calculated from the EPR and optical data, and results are discussed.
Keywords: EPR; VO2+; Metal ions; Optical absorption; SHOMH;

Novel fluorescent sensor for detection of Cu(II) in aqueous solution by Jia-Sheng Wu; Peng-Fei Wang; Xiao-Hong Zhang; Shi-Kang Wu (749-752).
A novel fluorescent chemosensor based on aminonaphthol, which can selectively recognize copper(II) over other metal ions in aqueous solution within a broad pH span, was synthesized.
Keywords: Molecular recognition; Aminonaphthol; Chemosensor; Copper(II); Aqueous solution; Fluorescence quenching;

The effect of (2-hydroxyethyl)trimethylammonium (2-HETMA) cation on the equilibrium of silicate oligomers in aqueous alkaline silicate solutions was investigated using 29Si NMR spectra. The results indicate role of structural directing of 2-HETMA in which it particularly directs the silicate species to the Q 4 1 Q 4 3 Q 4 4 silicate anion. Results reveal that composition of the alcohols in solution affect the distribution of anionic species. The effect of methanol concentration is also discussed.
Keywords: (2-Hydroxyethyl)trimethylammonium; 29Si NMR spectroscopy; Silicate species; Structure directing; Alcoholic silicate solution;

A detailed analysis of the vibrational spectra of carbonyl cyanide, diethynyl ketone and acetyl cyanide has been conducted in harmonic and anharmonic approximations. RHF, MP2 and density functional theory (DFT) methods with 6-311++G(2df,2p) basis sets and B3LYP functionals have been employed. Spectroscopic constants such as anharmonicity constants, rotational and centrifugal distortion constants, rotation–vibration coupling constants and Coriolis coupling coefficients have been calculated for each molecule and compared with the experimental data, where available. A close agreement between the calculated and experimental values of the spectroscopic constants has been obtained. Complete assignments have been provided to the fundamental bands, overtones and combination tones of the molecules. Density functional theory based anharmonic frequencies compare well with the experimental frequencies within ±18 cm−1 on an average. RHF and MP2 methods, however, give much higher values for the frequencies that need scaling even in the anharmonic approximation.
Keywords: Anharmonic frequencies; Carbonyl cyanide; Diethynyl ketone; Acetyl cyanide; DFT; Coupling constants; Anharmonic constants; Fundamental bands; Overtones; Combination tones;

The vibrational structure of (E,E′)-1,4-diphenyl-1,3-butadiene by Bjarke K.V. Hansen; Søren Møller; Jens Spanget-Larsen (770-778).
The title compound (DPB) was investigated by FT-IR spectroscopy in liquid solutions and by FT-IR linear dichroism (LD) measurements on samples aligned in stretched polyethylene. The LD data provided experimental assignments of molecular transition moment directions and vibrational symmetries for more than 40 vibrational transitions. The observed IR wavenumbers, relative intensities, and polarization directions were generally well reproduced by the results of a harmonic analysis based on B3LYP/cc-pVTZ density functional theory (DFT). The combined experimental and theoretical results led to proposal of a nearly complete assignment of the IR active fundamentals of DPB, involving reassignment of a number of transitions. In addition, previously published Raman spectra of DPB were well predicted by the B3LYP/cc-pVTZ calculations.
Keywords: Diphenylpolyene; Vibrational spectroscopy; Infrared; Linear dichroism (LD); Raman; Density functional theory (DFT);

Trimethoxypropylsilane (TMPS) and bis(trimethoxysilyl)ethane (BTMSE) were used as surface modifiers of metal vie the sol–gel process and dip coating. In addition to the single coating of Al, Cu and Sn, double treatments of Al were also conducted by combining coatings with these sol–gels in different sequences. Reflection and absorption infrared spectroscopy (RAIR) was employed to characterize and to trace the proceeding of the sol–gel process of the films. It was found that the silanol condensation occurs in the coating films on Al and the covalent linkage exists between the TMPS film and copper surface. From the assigned vibration modes, two conformers were identified in pure TMPS, TMPS sol–gel and coated film. A series of dip coating experiments with different concentrations of TMPS sol–gel was conducted, and the results from the collected RAIR spectra of the coated samples suggested that the coated Cu consistently has a better RAIR spectrum than that of the coated Al. The TMPS sol–gel appeared to have a better affinity to Cu than to Al. The temperature effect and the aging effect in the coating films were studied. X-ray photoelectronic spectroscopy (XPS) was employed to characterize the coated film, and the XPS data confirm the formation of the siloxane film from the silane coupling agents (SCA). Electrochemical impedance spectra (EIS) have been collected for bare Al and Cu, BTMSE sol–gel coated Al, and TMPS sol–gel coated Cu in 0.15 M NaCl solution. The corresponding electronic circuit parameters have been determined to match the experimental EIS data.
Keywords: Infrared spectra; Raman spectra; X-ray photoelectronic spectroscopy; Electrochemical impedance spectra; Trimethoxypropylsilane; Bis(trimethoxysilyl)ethane; Silane coupling agent;

The decomposition of trimethylsilane and tetramethylsilane has been investigated for the first time, using hot wire (catalytic) at various temperatures. Trimethylsilane is catalytic-dissociated in these species SiH2, CH3SiH, CH3, CH2Si. Time of flight mass spectroscopy signal of these species are linearly increasing with increasing catalytic-temperature. Time of flight mass spectroscopy (TOFMS) signals of (CH3)3SiH and photodissociated into (CH3)2SiH are decreasing with increasing hot filament temperature. TOFMS signal of (CH3)4Si is decreasing with increasing hot wire temperature, but (CH3)3Si signal is almost constant with increasing the temperature. We calculated activation energies of dissociated species of the parental molecules for fundamental information of reaction kinetics for the first time. Catalytic-dissociation of trimethylsilane, and tetramethylsilane single source time of flight coupled single photon VUV (118 nm) photoionization collisionless radicals at temperature range of tungsten filament 800–2360 K. The study is focused to understand the fundamental information on reaction kinetics of these molecules at hot wire temperature, and processes of catalytic-chemical vapour deposition (Cat-CVD) technique which could be implemented in amorphous and crystalline SiC semiconductors thin films.
Keywords: VUV time of flight mass spectroscopy; Catalytic-dissociation; Photofragmentation and photoionization; Activation energies; Molecular (CH3)SiH and (CH3)4Si; Cat-CVD;

Complexes of Cr(III), Mn(II), Co(II), Ni(II) and Cu(II) containing a tetradentate macrocyclic N-donor ligand have been prepared via template reaction of 2,3-pentanedione, ethylene-di-ammine and transition metal ions. The complexes have been characterized on the basis of the elemental analysis, molar conductance, magnetic moment susceptibility, IR, electronic and EPR spectral studies. The complexes are of high spin type and possess four coordinate tetrahedral five coordinate square pyramidal and six coordinated octahedral/tetragonal geometry.
Keywords: Macrocyclic ligands complexes; Magnetic moment; Spectral studies;

A Raman spectroscopic study of the uranyl phosphate mineral threadgoldite by Ray L. Frost; Jiří Čejka; Matt Weier (797-801).
Raman spectra of threadgoldite at 298 and 77 K are measured and interpreted for the first time. Bands related the (UO2)2+ and (PO4)3− stretching and bending vibrations are tenatively attributed together with the bands assigned to the stretching a and bending vibrations of water molecules and hydroxyls. Hydrogen-bonding network and H2O and (OH)−1 libration modes are mentioned. U–O bond lengths in uranyls are calculated via empirical relations R U–O  =  f1 and ν3(UO2)2+] Å. They are comparable to the values inferred from the single crystal structure analysis of threadgoldite.
Keywords: Threadgoldite; Phosphate; Raman spectroscopy; U–O bond length; Uranyl;

FT-IR, FT-Raman and SERS spectra of Vitamin C by C. Yohannan Panicker; Hema Tresa Varghese; Daizy Philip (802-804).
FT-IR and FT-Raman spectra of Vitamin c have been recorded and analysed. SERS spectrum was recorded is silver colloid. The molecule is thought to adsorb with the lactone ring in a tilted side on orientation with respect to the silver surface.
Keywords: Raman spectrum; IR spectrum; Surface enhanced Raman scattering (SERS); Silver colloid;

Ab initio calculations, FT-IR and X-ray crystal analysis, indicated that the most stable configuration of 3-oxo-2-(phenylhydrazono)-3-(thien-2-yl)-propionitrile is the anti phenylhydrazone structure 1. Stability of such a conformation, over the possible E-form, 2, that would be stabilized by intramolecular hydrogen bonding, is due to interaction between electron-pair domains of the N, S and O atoms. However, the simulated and experimental IR frequency data indicated intermolecular hydrogen bonding between NH and CN, the latter being lowered to 2214 cm−1. Studies on 3-oxo-3-phenyl-2-(phenylhydrazono)-propionitrile showed the same result, as well as, another intramolecular hydrogen association of the type N―H⋯O. This was clearly indicated by the absorbance of the carbonyl stretch at 1605 cm−1.These data indicated the existence of a bifurcated hydrogen bond in 1a and a single intermolecular association in 1b.
Keywords: 2-Arylhydrazono-3-oxonitriles; DFT; Vibrational assignment; Bifurcated hydrogen bond; X-ray crystal structure;

Spectroscopic studies on the interaction between riboflavin and albumins by Hongwei Zhao; Min Ge; Zhaoxia Zhang; Wenfeng Wang; Guozhong Wu (811-817).
The interactions between riboflavin (RF) and human and bovine serum albumin (HSA and BSA) were studied by using absorption and fluorescence spectroscopic methods. Intrinsic fluorescence emission spectra of serum albumin in the presence of RF show that the endogenous photosensitizer acts as a quencher. The decrease of fluorescence intensity at about 350 nm is attributed to changes in the environment of the protein fluorophores caused by the ligand. The quenching mechanisms of albumins by RF were discussed. The binding constants and binding site number were obtained at various temperatures. The distance between albumins and RF in the complexes suggests that the primary binding site for RF is close to tryptophan residue (Trp214) of HSA and Trp212 of BSA. The hydration process of albumins has also been discussed.
Keywords: Riboflavin; Albumin; Intrinsic fluorescence; Fluorescence quenching;

The vibrational spectra of 2,3-dihydroxy pyridine (DHP) and 2,4-dihyroxy-3-nitropyridine (DHNP) have been computed using B3LYP methodology and 6-31G** basis set. The solid phase FTIR and FT Raman spectra were recorded in the region 4000–400 and 3500–100 cm−1, respectively. A close agreement was achieved between the observed and calculated frequencies by refinement of the scale factors.
Keywords: Vibrational analysis; Infrared and Raman spectra; DFT calculation;

FT-Raman and FT-IR spectra, ab initio and density functional studies of 3,4-dichlorobenzyl alcohol by N. Sundaraganesan; B. Anand; Fang-Fang Jian; Pusu Zhao (826-832).
The Fourier transform Raman and Fourier transform infrared spectra of 3,4-dichlorobenzyl alcohol were recorded in the solid phase. The equilibrium geometry, harmonic vibrational frequencies, infrared intensities and Raman scattering activities, depolarization ratios, reduced masses were calculated by HF and density functional B3LYP method with the 6-311 G** basis set. The scaled theoretical wavenumbers showed very good agreement with the experimental values. The thermodynamic functions of the title compound were also performed at HF/6-311G** and B3LYP/6-311G** levels of theory. A detailed interpretations of the infrared and Raman spectra of 3,4-dichlorobenzyl alcohol is reported. The theoretical spectrograms for FT-IR spectra of the title molecule have been constructed.
Keywords: FT-IR and FT-Raman spectra; Ab initio and DFT; 3,4-Dichlorobenzyl alcohol; Vibrational analysis;

Absorption and luminescent spectra of several new synthesized pyrazolo-quinoline possessing different substituents are studied. Absorption spectra of all the considered compounds possess five relatively strong absorption bands at about 430, 320, 270, 253 and about 230 nm. A correlation between the bond lengths between the substituent molecule and mother molecule with the observed spectral shifts was found.Theoretical spectra obtained within semi-empirical quantum chemical AM1 calculation methods seem to be more widened compared to the experimental ones due to electron–vibration interactions. However generally a good coincidence between spectral positions between experimental and calculated spectral peak positions was achieved. The corresponding experimental spectra have an absorption edges situated at about 430 nm which appears in fairly good agreement with quantum chemical simulations, namely for absorption spectra calculated by semi-empirical AM1-method. The red shifts in the experimental luminescence spectra are a consequence of electron–vibration interactions which increase with the effective radius and polarizabilities of the particular substituents.
Keywords: Electrronic molecuolar spectra; Semi-empirical quantum-chemical methods;

Reactions of M(CO)6, where M = Cr and Mo with Schiff bases prepared by the condensation of ethanolamine with either acetylacetone or benzoylacetone were investigated. The reactions of Cr(CO)6 in benzene resulted in the formation of the tricarbonyl drivatives [Cr(CO)3(HL)], HL = acaceaH or baceaH. The HL proved to act as a tridentate ligand. The corresponding reactions with Mo(CO)6 in dioxane gave the oxo complexes [Mo2O6(HL)2] with HL was a bidentate. All prepared complexes were investigated using elemental analysis, IR, mass spectrometry, UV–vis absorption spectra and magnetic measurement. Thermal behaviors of the complexes were studied using by thermogravimetry (TG). Schemes for the thermal decomposition were proposed along with their mass fragmentation patterns.
Keywords: Chromium; Molybdenum; Metal carbonyls; Schiff bases; IR Spectra; Thermogravimetry;

Rectification of excitation with bathochromic shift induced by intense absorption of organic ligands during emission measurement of Eu(III) complex by Hui Zhao; Wei Su; Yanhua Luo; Yaohui Ji; Zengchang Li; Hongfang Jiu; Hao Liang; Biao Chen; Qijin Zhang (846-851).
Bathochromic shift in excitation spectrum was observed during emission measurement of Eu(DBM)3Phen containing dilute solution in methyl methacrylate (MMA). Detailed analysis shows that the reason of bathochromic shift is not the formation of molecule aggregation. It is caused by the intense absorption of ligands in the complex. Based on this model, a new method has been established to rectify excitation spectra before emission measurement of systems with different concentration. There exists a critical value of the absorption strength, which is 0.87 from calculation. Higher absorption than this value will cause the bathochromic shift of excitation peak. The wavelength whose absorbance is 0.87 will be the position of the strongest excitation peak. With 200 ppm and 500 ppm Eu(DBM)3Phen as the standard sample, relations between relative concentration and wavelength of excitation peak in Eu(DBM)3Phen system were deduced and plotted. Theoretical curves are in good agreement with experiment data except extra-dilute concentration, for partial decomplexation of the β-diketonate and phenanthroline ligands.
Keywords: Rare earths; Absorption; Fluorescence spectroscopy; Excitation;

A comparative investigation of the interaction of two pyrrole-substituted, mixed oxygen and nitrogen donor, macrocycles ligands have been designed and their coordination interaction with cobalt(II) is studied. Cobalt(II) salts combine with a tetradentate and hexadentate macrocyclic nitrogen/oxygen donor ligands and formed novel cobalt(II) complexes which are characterized by elemental analysis, molar conductance, magnetic moments, mass, 1H NMR, IR, electronic and EPR spectral studies. At the room temperature magnetic moment for cobalt(II) complexes lie in the range 4.70–5.01 BM, which is higher than the spin-only value. All the complexes are high-spin type and have three unpaired electrons. Therefore, the electronic confutation and the splitting of the orbital will be t 2 g 5 e g 2 .The electrochemical behaviour of the cobalt(II) complexes, the Co(III)/Co(II) couple are observed. Their positive potential indicates that metal in lower oxidation state is strongly bound to these ligands. The difference between the potential of the anodic peak and cathodic peak remains constant in all complexes. Also, the ratio between the cathodic peak current and square root of the scan rate is practically constant for the studied complexes.
Keywords: Macrocyclic; Cobalt(II); IR; Mass spectroscopy; 1H NMR; EPR; Magnetic moment; Cyclic voltammetry;

ZINDO/S and PM3 calculations for a biscyanide α-iminooxime cobalt macrocyclic complex by Leandro J. Cavichiolo; Tai Hasegawa; Fábio S. Nunes (859-862).
Molecular modeling and a detailed spectroscopic characterization of the macrocyclic complex [Co(dohpn)(CN)2] (dohpn = 2,3,9,10-tetramethyl-1,4,8,11-tetraazaundecane-1,3,8,10-tetraen-11-ol-1-olate and py = pyridine) is herein presented. Structural, electronic and vibrational features are discussed and assignments were proposed on the basis of semi-empirical (molecular mechanics, ZINDO/S and PM3) calculations.
Keywords: Cobalt–imineoxime macrocycle; UV–visible; Infrared; ZINDO/S;

Analysis of ultraviolet absorption spectrum of Chinese herbal medicine–Cortex Fraxini by double ANN by Lifei Bai; Haitao Zhang; Hongxia Wang; Junfeng Li; Lei Lu; Hanqi Zhang; Hongyan Wang (863-868).
A fast, accurate and convenient method for the simultaneous determination of multi-component in the Chinese herbal medicine was proposed by using ultraviolet absorption spectrum. In this method, dummy components were added to training sample, and a double artificial neural network (DANN) that has the function of high self-revision and self-simulation was used. Effect of other interference components could be eliminated by adjusting concentration of dummy components. Therefore, the accuracy of concentration prediction for multi-component in the complicated Chinese herbal medicine was improved. It has been realized that two effective components of Cortex Fraxini, aesculin and aesculetin, were simultaneously determined, without any separation. The predicted accuracy was 92% within the permitted relative errors. The measurement precisions of the aesculin and aesculetin were 0.37% and 1.5%, respectively.
Keywords: Double ANN; Dummy components; Chinese herbal medicine; Cortex Fraxini; Aesculin; Aesculetin;

The applicability of (−)-myrtenal as a chiral derivatizing agent in combination with 13C NMR spectroscopy was investigated. 13C NMR was found to be a valuable tool for the identification and enantiomer differentiation of primary amines including β-amino alcohols and vicinal diamines. The enantiomeric excess could be determined via automated deconvolution and integration, and was found to be in good accordance with the expected values even in the cases, when enantiomer differentiation was not possible in 1H NMR spectra.
Keywords: Amine; Amino alcohol; Chiral resolution; NMR spectroscopy; (−)-Myrtenal;

DFT(B3LYP, B3PW91) calculations in conjunction with three different basis sets have been utilized to investigate the variations in the bond lengths, dipole moment, rotational constants, IR frequencies, IR intensities and rotational invariants of ClCCCN. The nuclear quadrupole constants of chlorine (35Cl, 37Cl) and nitrogen (14N) of ClCCCN have been calculated on the experimental r s structure as well as on the B3PW91/6–311++g(d,p) optimized geometry and were found to be within the scale length of the experimental uncertainty. The slope and intercept obtained from the regression analysis between the B3LYP/6–311++g(d,p) level calculated and experimental B o values of ClCCCN were used to calculate reasonable values of rotational constants of all the rare isotopic species of ClCCCN having standard deviation ±0.048 MHz. All the spectroscopic parameters obtained from DFT calculations show satisfactory agreement with the available experimental data.
Keywords: Spectroscopic parameters; ClCCCN-DFT calculations;

Spectroscopy, crystal structure, valance molecular orbital energy level diagram and DFT study of cis-[Cr(2,2′-bipy)2Cl2](Cl)0.38(PF6)0.62 by Tapas Kar; Meng-Sheng Liao; Susobhan Biswas; Saikat Sarkar; Kamalendu Dey; Glenn P.A. Yap; Kevin Kreisel (882-886).
A new octahedral chromium(III) complex having 2,2′-bipyridine as ligand system was synthesized in methanol. Single crystal X-ray diffraction analysis shows that it possesses non-stoichiometry in its anionic primary covalency. It has also been studied by elemental analyses, optical spectroscopy (UV–vis, IR) and magnetic susceptibility data. DFT calculations (with B3LYP functional and double-ξ quality LANLDZ(D95V) basis set) were carried out to interpret the electronic and infrared spectra of the complex. The DFT optimized geometric structure for the complex is compared with the X-ray crystallographic data; the theory–experiment agreement is satisfactory.
Keywords: Spectroscopy; Crystal structure; 2,2′-Bipyridine; Density functional theory; Molecular orbital energy level diagram;

A theoretical and experimental study of vibrational properties of alkyl xanthates by Pär Hellström; Sven Öberg; Andreas Fredriksson; Allan Holmgren (887-895).
Geometrical structure and vibrational modes of potassium and sodium ethyl/heptyl xanthates were studied, using both theoretical and experimental methods. Both Hartree–Fock and density functional theory were used. The experimental method used was infrared absorption spectroscopy (FTIR). Our work showed that vibrational frequencies calculated with density functional theory, using the local density approximation, are in very good agreement with experiments. The results were not improved by using the more sophisticated and computationally demanding B3LYP functional.
Keywords: DFT; IR; Xanthate; Ab initio; Vibrational mode;

The interaction of superoxide dismutase (SOD) with aluminum (Al) ions was investigated by cyclic voltammetry, fluorescence spectroscopy and synchronous fluorescence spectroscopy. The electrochemical activity of the SOD enzyme electrode was inhibited irreversibly by the addition of Al. Meanwhile, the static fluorescence quenching mechanism further revealed the existing of molecular complex of SOD with Al3+. The association constant was obtained from Lineweaver-Burk plot. The experimental results of voltammetry and fluorescence spectroscopy indicated that the conformation of SOD molecule was altered by the formation of Al–SOD complex. It may influence the activity of SOD enzyme since the optimum action of SOD depends upon a particular configuration of electrostatic charges in the enzyme molecule.
Keywords: Aluminum ions; Superoxide dismutase (SOD); Cyclic voltammetry; Fluorescence spectroscopy;

Meso-tetra(4-sulfonatophenyl)porphyrin (TPPS) interacts with trinitrotoluene (TNT) and forms a 1:1 complex with a new absorbance peak at 422 nm. TNT quenches TPPS emission intensity at 645 and 702 nm when excited at 413 nm. The TPPS–TNT complex is formed in the ground state on the basis of a linear Stern–Volmer plot indicative of static quenching. The association constants determined from absorbance and fluorescence studies are in excellent agreement.
Keywords: Porphyrins; Trinitrotoluene; Absorbance; Association constant; Fluorescence quenching; Fluorescence lifetime;

A novel β-diketone with an electro-transporting oxadiazole group, 1-(4′-(5-(4-methylphenyl)-1,3,4-oxadiazol-2-yl)biphenyl-4-yl)-4,4,4-trifluorobutane-1,3-dione (MPBDTFA), was prepared with high yield. With this synthesized ligand as the first ligand and 1,10-phenanthroline (Phen) as the secondary ligand, a new europium(III) ternary complex, Eu(MPBDTFA)3Phen, was synthesized. The new β-diketone and its europium(III) ternary complex were characteristized by elemental analysis, thermo-gravimetric analysis, IR and UV–visible spectroscopies. Photoluminescence measurements indicated that the energy absorbed by the organic ligands was efficiently transfered to the central Eu3+ ions, and the complex showed intensely and characteristically red emissions due to the 5 D 0  →  7 F j transitions of the central Eu3+ ions. With an electro-transporting group in molecule and highly thermal stability, the synthesized Eu(III) ternary complex is expected as a red-emitting candidate material for fabrication of organic light-emitting diodes (OLEDs).
Keywords: Optical material; Europium organic complex; Electro-transporting group; Luminescence;

Synthesis, characterizations and luminescent properties of three novel aryl amide type ligands and their lanthanide complexes by Wei-Na Wu; Wen-Bing Yuan; Ning Tang; Ru-Dong Yang; Lan Yan; Zi-Hua Xu (912-918).
Three new aryl amide type ligands, N-(phenyl)-2-(quinolin-8-yloxy)acetamide (L1), N-(benzyl)-2-(quinolin-8-yloxy)acetamide (L2) and N-(naphthalene-1-yl)-2-(quinolin-8-yloxy)acetamide (L3) were synthesized. With these ligands, three series of lanthanide(III) complexes were prepared: [Ln(L1)2(NO3)2]NO3, [Ln(L2)2(NO3)2(H2O)2]NO3·H2O and [Ln(L3)2(NO3)2(H2O)2]NO3·H2O (Ln = La, Sm, Eu, Gd). The complexes were characterized by the elemental analyses, molar conductivity, 1H NMR spectra, IR spectra and TG–DTA. The fluorescence properties of complexes in the solid state and the triplet state energies of the ligands were studied in detail, respectively. It was found that the Eu(III) complexes have bright red fluorescence in solid state. The energies of excited triplet state for the three ligands are 20 325 cm−1 (L3), 21 053 cm−1 (L2) and 22 831 cm−1 (L1), respectively. All the three ligands sensitize Eu(III) strongly and the order of the emission intensity for the Eu(III) complexes with the three ligands is L3  > L2  > L1. It can be explained by the relative energy gap between the lowest triplet energy level of the ligand (T) and 5D1 of Eu(III). This means that the triplet energy level of the ligand is the chief factor, which dominates Eu(III) complexes luminescence.
Keywords: Lanthanide complexes; Aryl amide; Synthesis; Fluorescence properties; Triplet state energy;

The interaction between norfloxacin and calf thymus double-stranded DNA (dsDNA) has been studied by a resonance light scattering (RLS) technique with a common spectrofluorometer. The characteristics of RLS spectra, the effective factors and optimum conditions of the reaction have been investigated. In Britton–Robinson (BR) buffer (pH 5.87), norfloxacin has a maximum peak 405.5 nm and the RLS intensity is remarkably enhanced by trace amount of calf thymus dsDNA due to the interaction between norfloxacin and dsDNA. The binding of norfloxacin to DNA forms large particles, which were characterized by RLS spectrum, scanning electron microscopy (SEM), ultraviolet-visible (UV–vis) spectrum, and fluorescence spectrum. Based on the enhanced RLS intensity, a novel method for sensitive determination of calf thymus dsDNA concentration ranging from 0.02 to 2.3 μg ml−1 was developed. The determination limit (3σ) was 1.2 ng ml−1. The method is simple, rapid, practical and relatively free from interference generated by coexisting substance, as well as much more sensitive than most of the reported methods. Three synthetic samples of ctDNA were determined with satisfactory results.
Keywords: DNA; Norfloxacin; Resonance light scattering;

A novel colorimetric sensor based on 8-hydroxy quinoline-5-azo-4′-nitrobenzene (1) was prepared and used for recognizing anions. 1 and its metal complex (1·Co) were found to show response to anions such as CH3CO2 , H2PO4 , HSO4 , F and dramatic color changes were observed. The selectivity and sensitivity of 1 and 1·Co for sensing anions were different, which was in the order of CH3CO2  > F  > H2PO4  ≫ HSO4 for 1 and H2PO4  > HSO4  > CH3CO2  ∼ F for 1·Co, respectively. In CH3CN, sensor 1·Co exhibited excellent specificity toward H2PO4 , and the color variety was dependent on the concentration of H2PO4 which was attributed to anion structure and stability of anionic complex (1-anion), metal complex (1-Co) and inorganic complex (Co-anion).
Keywords: Anion recognition; Colorimetric assay; Dihydrogen-phosphate; 8-Hydroxy quinoline-5-azo-4′-nitrobenzene;

We studied the dependence of the Raman spectra on the concentration of PHBA aqueous solution under UV laser excitation. Through analyzing the spectra, we conclude that the interaction between PHBA ions and H2O molecules is weak. To further explore the problem, we studied the interaction between PHBA ions and H2O molecules by virtue of theoretical calculations, DFT-B3PW91/6-31+g* was employed. We draw a coincident conclusion with the experiments and dug out the reasonable interaction model that reflects the actual interaction configuration between PHBA ions and H2O molecules. We supply a new thinking for studying interactions between solute molecules and solvent molecules, which also can be applied to interactions between solute molecules and other solute molecules in solutions.
Keywords: p-Hydroxybenzoic acid (PHBA); Density functional theory (DFT); Calculated Raman frequencies; Interaction model;

An extensive computational study of thiophene-2-aldehyde conformers syn and anti has been carried out using density functional (DFT). From these calculations, B3LYP/6-31G(d) has been chosen as it produces results remarkably close in comparison with experimental ones, with less demanding computational time. Data obtained from DFT computation were used to perform a normal coordinate analysis to complement and give insight in the experimental vibrational assignment. Calculated dipole moments and relative stabilities of isomers coherently support experimental statements given in the literature.
Keywords: Thiophene-2-aldehyde; Conformers; DFT; Normal coordinate analysis;

In 0.01 M 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (Hepes), pH 7.4 and room temperature, the binding of neodymium to N,N′-ethylenebis[2-(o-hydroxyphenolic)glycine] (EHPG), or N,N′-di(2-hydroxybenzyl)ethylenediamine-N,N′ diacetic acid (HBED) had been studied from 210 to 330 nm by means of difference UV spectra. Two peaks at 240 and 292 nm appear in difference UV spectra after neodymium binding to EHPG or HBED. The 1:1 stable complex can be confirmed from spectral titration curves. The molar extinction coefficient of Nd–EHPG and Nd–HBED complexes are Δɛ Nd–EHPG  = (12.93 ± 0.21) × 103  cm−1  M−1, Δɛ Nd–HBED  = (14.45 ± 0.51) × 105  cm−1  M−1 at 240 nm, respectively. Using EDTA as a competitor, the conditional equilibrium constants of the complexes are log  K Nd–EHPG  = 11.89 ± 0.09 and log  K Nd–HBED  = 12.19 ± 0.15, respectively. At the same conditions, fluorescence measurements show that neodymium binding to EHPG leads to a quenching of the fluorescence of EHPG at near 310 nm. However, there is no obvious fluorescence change of HBED at 318 nm with the binding of neodymium to HBED.
Keywords: HBED; EHPG; Neodymium; Spectra;

Organotin(IV) complexes of tribenzyltin(IV) chloride and di(para-chlorobenzyl)tin(IV) dichloride with thiohydrazides have been reported. The ligands synthesized were bidentate coordinating through sulphur and terminal nitrogen atoms. These form 1:1 metal–ligand complexes. The following organotin(IV) complexes have been synthesized: (C6H5CH2)3Sn(L1)Cl, (p-ClC6H4CH2)2Sn(L1)Cl2, (C6H5CH2)3Sn(L1)Cl, (p-ClC6H4CH2)2Sn(L2)Cl2, (C6H5CH2)3Sn(L3)Cl, (p-ClC6H4CH2)2Sn(L3)Cl2, where (L1): 2-phenylethyl N-thiohydrazide, (L2): N-(2-phenylethyl-N-thio)-1,3-propane diamine, (L3): N-(2-phenylethyl-N-thio)-1,2-ethane diamine. The complexes were synthesized by directly mixing, refluxing and stirring the ligands with organotin(IV) chlorides in a suitable solvent. The complexes were found to be pure and were characterized by elemental analysis, electronic, infrared, 1H and 13C NMR spectroscopy. These complexes were also studied for their thermal decomposition by thermogravimetry (TG) and differential thermal analysis (DTA). Various kinetic and thermodynamic parameters, viz. activation energy (E a), order of reaction (n), apparent activation entropy (S #) and heat of reaction (ΔH) have been determined by using Horowitz–Metzger method. It was observed that these complexes are highly stable and the thermal degradation of these complexes is a spontaneous process. The ligands and their tin complexes have also been screened for their fungitoxicity activity and found to be quite active in this respect.
Keywords: Organotin(IV) chloride; Thiohydrazides; Spectral; Thermal; Fungitoxicity;

A comparative study of infrared and Raman spectra of dl-valine dl-valinium picrate (dl-VVP) and dl-methionine dl-methioninium picrate (dl-MMP) at the room temperature in 4000–50 cm−1 range helps to determine the effect of hydrogen bonds in these crystals. The existence of the zwitterion and the protonated form in both the crystals has been observed. In dl-MMP, the methionine and the methioninium residues form a dimer through a strong hydrogen bond between them in the crystal. The characteristic bands due to gem-methyl group are observed in the case of dl-VVP. Factor group analysis has been made and the numbers of vibrational modes have been calculated. The tentative assignments of the observed bands are given. The picrate group forms the anion in both the crystals and it is unaffected by the presence of the cations.
Keywords: dl-Valine dl-valinium; dl-Methionine dl-methioninium; Picrate; Infrared and Raman spectra; Intermolecular hydrogen bonding; Factor group analysis; Group frequencies;

The molecular structure and vibrational spectra of 1-amino-5-benzoyl-4-phenylpyrimidin-2(1H) (C17H13N3O2) have been investigated by Hartree-Fock and density functional method using standard B3LYP with 6-31G(d) basis set. The calculated results of the geometric bond lengths and bond angles obtained by using HF and DFT (B3LYP) are in very good agreement with the experimental values. Comparison of the observed fundamental vibrational frequencies of 1-amino-5-benzoyl-4-phenylpyrimidin-2(1H) (C17H13N3O2) and calculated results by density functional B3LYP and Hartree-Fock methods indicate that B3LYP is superior to the scaled Hartree-Fock approach for molecular vibrational problems.
Keywords: 1-Amino-5-benzoyl-4-phenylpyrimidin-2(1H); IR spectra; DFT; HF; Vibrational assignment; Crystal structure;

Polarized IR and Raman spectra and ab initio calculations for bis(guanidine) zirconium bis(nitrilotriacetate) hydrate single crystal [C(NH2)3]2{Zr[N(CH2COO)3]2}(H2O)—The new laser Raman converter by J. Hanuza; M. Mączka; W. Sąsiadek; S. Roszak; P. Lipkowski; A.A. Kaminskii; E. Haussühl; J. Hulliger; Al.-Agail Hussin (969-984).
Fourier transform polarized IR and Raman spectra of bis(guanidine) zirconium bis(nitrilotriacetate) hydrate single crystal [C(NH2)3]2{Zr[N(CH2COO)3]2}(H2O) have been measured in the regions 30–4000 and 80–4000 cm−1 and correlated with X-ray structural data. The factor group analysis has been applied in the discussion of the dichroic dependence of the vibrational modes. The assignment of the internal vibrations for the {[Zr(nitrilotriacetate)2]}2− complex ion has been based on the ab initio quantum chemical calculations. The usefulness of the studied crystal as Raman laser converter was analyzed basing on the comparison of the spontaneous and stimulated Raman spectra.
Keywords: Bis(guanidine) zirconium Bis(nitrilotriacetate; Polarized IR and Raman spectra; Factor group analysis; Quantum chemical calculations; Laser Raman converter;

The effect of ionic strength on the UV–vis spectrum of congo red in aqueous solution by Thomas E. Sladewski; Alesha M. Shafer; Craig M. Hoag (985-987).
The major peak near 498 nm in the ultraviolet–visible spectrum of congo red in aqueous solution shifts toward the blue while the molar absorptivity of this peak decreases predictably with increasing ionic strength. The shift was observed for solutions in which ionic strength was varied from 0.0 to 1.8 M using the uni–univalent ionic compounds, NaCl, NaClO4, KNO3 and KBr separately. A plot of the log of the absorbance at the peak versus ionic strength was linear as well as a plot of the log of the wavelength of the major peak (shifted from 498 nm) versus the ionic strength. The slopes of each of these plots were somewhat different depending on the ionic compound.
Keywords: Spectroscopy; Congo red; Blue shift; Ionic strength;

Spectroscopic studies on the interaction between 3,4,5-trimethoxybenzoic acid and bovine serum albumin by Yan-Jun Hu; Hua-Guang Yu; Jia-Xin Dong; Xi Yang; Yi Liu (988-992).
The interaction between 3,4,5-trimethoxybenzoic acid (TMBA) and bovine serum albumin (BSA) was studied by fluorescence and UV–vis absorption spectroscopy. In the mechanism discussion, it was proved that the fluorescence quenching of BSA by TMBA is a result of the formation of TMBA–BSA complex. Quenching constants were determined using the Stern–Volmer equation to provide a measure of the binding affinity between TMBA and BSA. The thermodynamic parameters ΔH, ΔG, ΔS at different temperatures were calculated, and electrostatic interactions play an important role to stabilize the complex. The distance r between donor (BSA) and acceptor (TMBA) was obtained according to fluorescence resonance energy transfer (FRET).
Keywords: 3,4,5-Trimethoxybenzoic acid; Bovine serum albumin; Fluorescence quenching; Thermodynamic parameters; Fluorescence resonance energy transfer;

Europium and Terbium were found to form ternary complexes with ethylenediammine tetraacetic acid (EDTA) and ortho-phenanthroline (o-phen) in aqueous solution in the pH range of 6–8. These ternary complexes were found to have 1:1:1 composition and showed strong fluorescence properties. The method is made use of for the determination of these lanthanide ions in presence of excess amounts of other lanthanide ions. The lowest detection limit was calculated as 30 and 65 ng/ml of Tb3+ and Eu3+, respectively.
Keywords: Europium; Terbium; Ternary complexes; Fluorescence studies; Interference studies;

Spectrophotometric and spectrofluorimetric methods for analysis of acyclovir and acebutolol hydrochloride by Hisham E. Abdellatef; Magda M. El-Henawee; Heba M. El-Sayed; Magda M. Ayad (997-999).
Simple and sensitive spectrophotometric and spectrofluorimetric methods are described for analysis of acebutolol hydrochloride. The proposed methods are based on oxidation of the selected drug with cerium(IV) ion in acidic medium with subsequent measurement of either the decrease in absorbance at 320 nm or the fluorescence intensity of the produced cerous(III) ion at 363 nm (excitation at 250 nm). Beer's law obeyed from 1.0–7.0 μg ml−1 and 0.25–2.5 μg ml−1 acebutolol hydrochloride, using the spectrophotometric and spectrofluorimetric method, respectively. The proposed methods were successfully applied for determination of the selected drug in its pharmaceutical preparation with good recoveries.
Keywords: Spectrophotometric; Spectrofluorimetric; Acebutolol hydrochloride; Cerium(IV);

We show that two of the three bands assigned to SPCN are assignable to cyanogen and that the bands assigned to SPCl are done so in error, with the 712 cm−1 band in the spectrum of Allaf and Odeh assignable to HCN. There is no evidence for either ClPS or SPCN in the spectra shown. Finally low resolution IR spectroscopy by itself, whilst useful in assisting in the identification of pyrolysis products does not provide unambiguous identification and requires support by rigorous computation, band modelling and correct use of the literature. None of these are evidenced in the present paper of Allaf and Odeh nor indeed in the work that was the subject of our previous criticism and re-analysis.
Keywords: Infrared spectroscopy; Pyrolysis; Mis-assignment;