Inorganic Chemistry Communications (v.5, #3)

Contents List (iii-iv).

Alkenyl ruthenium complex, Ru(CHCHR)(Cl)(CO)(PPh3)2 1, reacted with allenes 2 to give η3-allyl ruthenium complexes, Ru(η3-2-alkenylallyl)(Cl)(CO)(PPh3)2 3, in good yields. The reaction depends on the structure of the alkenyl group. When R was phenyl or methoxycarbonyl group, the carbometallated complex 3 was yielded as a sole product. However, when R was butyl or trimethylsilyl group, besides the carbometallation product as main product, was obtained a small amount of 2-unsubstituted η3-allyl ruthenium complex which was formed via β-elimination of the alkenyl complex followed by the reaction with allene. Structure of 3 was determined by the X-ray crystal structure analysis.
Keywords: η3-Allyl ruthenium complex; Alkenyl ruthenium complex; Carbometallation; X-ray analysis;

The divalent cation-induced DNA condensation studied by atomic force microscopy and spectra analysis by Xue-Guang Sun; En-Hua Cao; Xiao-yan Zhang; Dage Liu; Chunli Bai (181-186).
Three types of DNA condensates in the presence of divalent metal ion (Mg, Mn and Cu) and EB simultaneously have been observed by atomic force microscopy (AFM). In the presence of Mg (II) and EB, DNA molecular exhibits three or four maggot-like branch crossing structures at the same point, which were constructed by some bead-like particles in each branch. However, in the presence of Cu (II) or Mn (II)–EB, DNA molecular forms a network or a semicircular structure, respectively. Their average height was 0.95±0.5 nm (Cu (II)–DNA–EB), 17±5 nm (Mg (II)–DNA–EB) and 12±3 nm (Mn (II)–DNA–EB), respectively. However, DNA molecular or DNA–EB complex still remained a line double-stranded structure. The fluorescence, melting point and CD spectra indicate that the different morphologies induced by divalent metal ion (Mg (II), and Mn (II) and Cu (II)) are related to its binding position in molecular DNA.
Keywords: Atomic force microscopy; DNA condensation; Divalent metal cation; DNA; Circular dichroism;

The photoluminescence characteristics of Tb2S3 nanoparticles embedded in sol–gel silica xerogel by Ping Yang; Meng Kai Lü; Chun Feng Song; Guang Jun Zhou; Dong Xu; Duo Rong Yuan (187-191).
The silica xerogel doped with Tb2S3 nanocrystallites has been prepared by sol–gel process. UV–Vis spectra, transmission electron micrograph (TEM), excitation spectra and photoluminescence (PL) spectra of doped xerogel samples have all been investigated at room temperature. A novel luminescent phenomenon has been observed from Tb2S3 nanoparticles doped silica xerogel. The emission spectrum of the doped sample shows high fluorescence intensity. The photoluminescence spectrum of the doped samples consists of two emission bands, one at 440 nm and the other at 600 nm. The sharp emission band of Tb2S3 from the doped samples has been assigned to the luminescence centers of Tb2S3 quantum dots in the porous phosphorescence silica xerogel.
Keywords: Sol–gel; Silica xerogel; Tb2S3 nanocrystallites; Luminescence;

Reaction of equimolar amounts of [Co2(CO)6(dppm)] and [Cr(η6-C6H5)(CCCH2NMe2)(CO)3] (1) in benzene gives the novel heterotrimetallic complex [Cr(η6-C6H5){(μ22-CCCH2NMe2)Co2(CO)4(dppm)}(CO)3] (2) in 40% yield. The X-ray structure analysis of 2 reveals that the Cr(CO)3 tripod adopts a nearly anti-eclipsed conformation.
Keywords: Dicobaltcarbonyl; (η6-arene)tricarbonylchromium; Propargylamine; dppm; X-ray molecular structure;

A new three-dimensional (3-D) neutral coordination polymer, [Cd(NA)2] 1, has been synthesized under hydrothermal reaction conditions. The structure of 1 is self-assembled from binuclear square pyramidal cadmium that is in favor of non-interpenetrating open-frameworks and square pyramidal geometry of cadmium.
Keywords: Coordination polymer; Three-dimensional structure; Hydrothermal reaction; Binuclear cadmium; Square pyramidal cadmium; Cadmium nicotinate;

A near planar disilver complex of 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine by Edwin C. Constable; Catherine E. Housecroft; Benson M. Kariuki; Natalie Kelly; Christopher B. Smith (199-202).
The ligand 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine forms a 2:2 complex with silver(I) rather than the expected [4×4] grid; each of the two silver centres is in a near square-planar coordination environment.
Keywords: 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine; Silver complex; Crystal structure; Supramolecular chemistry; Grid;

Cationic heterobimetallic {[P(C6H4CH2NMe2-2)3]Ag-bipy-Cu[P(C6H4CH2NMe2-2)3]}2+(OTf,PF6 ) (5) (bipy = 4,4-bipyridine, OTf=OSO2CF3) is accessible by the subsequent reaction of [P(C6H4CH2NMe2-2)3]AgOTf (1) with bipy (2) to afford {[P(C6H4CH2NMe2-2)3]Ag(bipy)}+(OTf) (3), which on treatment with equimolar amounts of {[P(C6H4CH2NMe2-2)3]Cu}+(PF6 ) (4) produces 5. In 5 the respective group-11 metal(I) centres are bridged by the π-conjugated organic ligand bipy. The electrochemical behaviour of 5 is reported.
Keywords: 4,4-Bipyridine; Copper; Electrochemistry; Heterobimetallic; Phosphane; Silver;

Efforts to prepare tetranuclear manganese oxo complexes that model the water oxidizing center in Photosystem II have focused largely on using unsubstituted acetate and benzoate ligands. We report the reaction of Mn(O2CCF3)2, (n-Bu4N)[MnO4], and bipyridine in trifluoroacetic acid yields the compound [Mn4O2(O2CCF3)8(bpy)2]. X-ray crystallographic studies of this complex show a non-planar {Mn4O2}8+ center with an arrangement of bipyridine and bridging trifluoroacetate ligands that is very similar to the acetate complex [Mn4O2(O2CCH3)7(bpy)2]+ [Christou, et al. J. Am Chem. Soc. 11 (1989) 2086]. The structure differs, however, in that the coordination sites occupied previously by a bridging bidentate acetate ligand are occupied by two terminal monodentate trifluoroacetate ligands in a cis arrangement. One of the terminal trifluoroacetate ligands is hydrogen-bonded to a co-crystallized trifluoroacetic acid molecule.
Keywords: Oxo-bridged manganese complexes; Trifluoroacetate; X-ray crystal structure; H-bonding; Carboxylate shift;

The generation of a trinuclear nickel(II) core maintained by tridentate acetate bridges by Harry Adams; Scott Clunas; David E. Fenton; Thomas J. Gregson; Paul E. McHugh; Sharon E. Spey (211-214).
The asymmetric compartmental proligand HL B bearing a tridentate N2O donor set and a bidentate NO donor set has given the novel trinuclear nickel(II) complex [Ni 3( L B )2(OAc)2(NCS)2] in which there are two tridentate acetate bridges each having a μ312-bridging mode.
Keywords: Crystal structure; Trinuclear nickel(II) complex;

Synthesis and structural characterization of two chain complexes of Mn(II) containing 2-aminopyridinium by Chang-Wei Su; Chi-Phi Wu; Jhy-Der Chen; Lin-Shu Liou; Ju-Chun Wang (215-219).
The 2-aminopyridine ligand has been exploited in preparation of divalent metal complexes of the formulae [H(2-ampy)][MnCl3(H2O)] 1 and [H(2-ampy)]2[Mn2Cl6(2-ampy)2] 2, where 2-ampy is 2-aminopyridine. Their crystal structures have been determined by X-ray crystallography. Both complexes self-assemble through similar hydrogen bonding motifs which involve three N–H⋯Cl interactions between the 2-aminopyridinium cation and the chloride atoms. Each repeating unit of complexes 1 and 2, [MnCl3(H2O)] and [Mn2Cl6(2-ampy)]2−, respectively, is doubly edge-sharing to form one-dimensional chains which are cross-linked by hydrogen bonding to the [H(2-ampy)]+ cations. In complex 2, two different 2-aminopyridine molecules were observed. One bridges the Mn atoms directly, while the other, through hydrogen bonding interaction, bridges Mn atoms via the chloride atoms. The structural role of the 2-aminopyridinium cation on the aggregation of the metal ions is discussed.
Keywords: N–H⋯Cl hydrogen bonding; 2-Aminopyridine; Manganese complex; Self-assembly;

The complex [Co(H 2 L)]Cl 2·4H 2 O  ( 1 ) (H2L=2,13-bis(2-carboxymethyl)-5,6-dimethyl-2,6,13,17-tetraazatricyclo[14,4,01.18,07.12]docosane) has been synthesized and structurally characterized. The title compound contains a centrosymmetric cation with the chloride anions and water molecules. The coordination geometry around the cobalt(II) ion is a distorted octahedron with the secondary and tertiary amines of the macrocycle and two oxygen atoms of the pendant carboxymethyl groups. Electronic spectra and effective magnetic moment of the complex also reveal a high-spin six-coordinated geometry.
Keywords: Crystal structure; Cobalt(II) complex; N-carboxymethyl pendant group; Tetraaza macrocycle;

7 Li , 23 Na , 39 K and 133 Cs NMR spectrometric comparative study of 0.05 M alkali metal chloride hydrolysis in aqueous solutions 3.4  M Me 4 NCl/Me 4 NOH at 25 °C is performed. It is found that chemical shifts of all nuclei involved are sensitive to variations of ionic strength and pH. Stability constants for Li+, Na+, K+ and Cs+ lg  K(M+OH⇔MOH) are found to be −0.04 (0.05), −0.93 (0.04), −0.7 (0.2) and −0.8 (0.1), respectively. The stability of CsOH is estimated to be the same as that of NaOH and KOH within an experimental error. No evidence of chloro-complexes formation was found.
Keywords: Equilibrium constants; 7 Li , 23 Na , 39 K and 133 Cs NMR spectrometry; Alkali cation hydroxides;

Four new optically active complexes of the composition LnL3Cl3 (where, L=(S,S)-(+)-2,3-dimethoxyl-N,N -dimethyl-1,4-diaminobutane, Ln=La3+, Sm3+, Pr3+ and Nd3+) were prepared and characterized on the basis of their chemical analyses, molar conductance, magnetic properties, CD, XPS, visible and IR spectra. It is found that the complexes behave as non-electrolytes in DMSO and in methanol solution and possess the stoichiometric ratio of Ln:C:N:O:Cl =1.1:24.0:6.1:6.0:3.1 which is consistent with the analyses data. The magnetic moments of the complexes show little deviation from the Van Vleck values, indicating that 4f electrons do not participate in bond formation in these chelates. The thermal analysis revealed that all the complexes are anhydrous. Their dominant conformers were determined from CD spectra. A nine-coordinated model was proposed for these complexes.
Keywords: Lanthanide (III); (S,S)-(+)-2,3-dimethoxyl-N,N -dimethyl-1,4-diaminobutane; Optically active complexes; CD spectra;

A new family of lanthanide coordination polymers with the general formula [Ln(SIP)(H2O)4] n (Ln=Eu, Gd, Ce, 13; and NaH2SIP=5-sulfoisophthalic acid monosodium salt) was hydrothermally synthesized and characterized by IR, elemental analysis, single-crystal X-ray crystallography and powder X-ray diffractions. X-ray studies indicated that these compounds are isostructural and adopt an electrically neutral and undulating two-dimensional layer structure constructed from fused {[Eu(H2O)4]3(SIP)3} pseudo-hexagonal grids. Thermogravimetric measurements in N2 revealed that all exhibit weight losses corresponding to four water molecules per formula unit around 120 °C and the dehydrated compounds are stable up to ca 510 °C. The fluorescence spectrum showed that [Eu(SIP)(H2O)4] n displays intense red fluorescence in the solid-state. The paramagnetism for [Gd(SIP)(H2O)4] n in the range 5–300 K reveals no magnetic coupling via SIP ligand.
Keywords: Hydrothermal synthesis; Lanthanide; Coordination polymer; Fluorescence;