Inorganic Chemistry Communications (v.6, #1)

Contents List (iii-iv).

Author Guide (I-V).

The one-dimensional coordination polymer, [Ni3(dpa)4F2][Ni3(dpa)4(H2O)2](BF4)2·2CH3OH (dpa=bis(2-pyridyl)amido ligand), has been constructed. The title complex crystallizes in the triclinic system, space group P 1 ̄ , with a=11.5966(1), b=19.5609(2), c=20.1509(2) Å, α=79.5672(4), β=75.4196(4), γ=76.2199(5)°, Z=2. The rare type hydrogen bonding of O–H⋯F–Ni links the two kinds of the trinickel metal string complexes as building blocks.
Keywords: Hydrogen bonding; Coordination polymer; Metal string complexes; Supramolecular chemistry;

Crystal structure and modeling calculation of the columnar helix 2,6-Bis(imino)phenoxy iron(III) chloride by Lingqin Han; Jianlong Du; Haijian Yang; Honggen Wang; Xuebing Leng; Artur Galstyan; Snežana Zarić; Wen-Hua Sun (5-9).
Crystal structure of novel bis(imino)phenoxychloro-iron(III) chloride demonstrated a columnar helix through hydrogen bonding of anion–cation molecules and intermolecular π–π interactions, along with the syntheses and characterization of the new compounds. A quantum-chemical single point calculations of the interaction energies were performed on the basis of the X-ray structural data.
Keywords: Self-assembly; Ion pair; Columnar helix; π–π interaction;

The compound [CuII{C6H4(NH2)2}2(NO3)2], 1 has been prepared and characterized by spectroscopic methods and single crystal X-ray diffraction. 1 crystallizes in the orthorhombic space group Pcab (No. 61), with a=7.905 (4) Å, b=9.865 (7) Å, c=20.621 (9) Å and Z=4. The structure was solved by direct method and refined by full-matrix least-squares on F 2 to R=0.0351 for 1160 reflections with I>2σ(I). In the crystal structure of 1, an extended hydrogen bonding network is formed involving copper coordinated amine and nitrato ligands. Compound 1 displays emission in solution at room temperature in the visible region furnishing the first example of an emissive transition metal complex, where the ligand is benzene-1,2-diamine (φ em=0.095, τ=2.97 ns).
Keywords: Benzene-diamine Cu(II) complex; Crystal structure; Supramolecular network; Room-temperature emission;

A unique 3d–4f mixed metal trinuclear compound, [Cu2Gd(L)2(NO3)2]NO3 (1; H2L=2,6-di(acetoacetyl)pyridine), is derived from a ‘one-pot’ reaction with H2L,Cu(NO3)2·3H2O and Gd(NO3)3·5H2O. Two L2− providing one central 2,6-diacylpyridine site and two terminal 1,3-diketonate sites hold two CuII ions and GdIII ion and form a linear Cu–Gd–Cu trinuclear core. This compound shows ferromagnetic interaction between CuII and GdIII.
Keywords: Copper(II); Gadorinium(III); Ferromagnetic interaction; Trinuclear complex;

Dinuclear zinc(II) complexes of a [6,6]-unsymmetrical compartmental ligand by Harry Adams; Laura R Cummings; David E Fenton; Paul E McHugh (19-22).
The unsymmetric compartmental proligand HL bearing adjacent but dissimilar tridentate N2O donor sets each capable of forming a six-membered chelate ring at a metal centre has given the dinuclear zinc(II) complexes [Zn 2 L (OAc)2](BPh 4)2 1 and [ Zn 2 L (OAc)(NCS)2 ] 3. The crystal structures of these complexes are reported together with that of [Ni 2 L (OAc)2(MeOH)](BPh 4)2 2.
Keywords: Crystal structure; Dinuclear nickel(II) complex; Dinuclear zinc(II) complexes;

Synthesis and structure of a gallate of strontium with Sr–C–Ga three-center two-electron bonds by Matthias Westerhausen; Sabine Weinrich; Manfred Oßberger; Norbert Mitzel (23-25).
The addition reaction of strontium bis[bis(trimethylsilyl)amide] with triethylgallane yields quantitatively strontium bis[triethyl-bis(trimethylsilyl)aminogallate] (1). The strontium cation shows the unusual low coordination number of four to two nitrogen and two carbon atoms. Sr–C bond lengths with a mean value of 282 pm are observed with the Sr–C–Ga three-center two-electron bonds. Due to the mainly ionic character of this compound a fast exchange of the bridging and terminal ethyl groups is observed on the NMR time scale.
Keywords: Strontium; Gallium; Addition reactions; Lewis acid/base reactions;

New supramolecular dinuclear rare earth Schiff base podates by Wanda Radecka-Paryzek; Małgorzata T Kaczmarek; Violetta Patroniak; Izabela Pospieszna-Markiewicz (26-29).
The metal-promoted reactions between 2,6-diacetylpyridine and 4-methyl-1,2-phenylenediamine, 3-azaoctane-1,8-diamine (spermidine) or N,N -bis(2-aminoethyl)-1,3-propanediamine in the presence of lanthanide(III) ions acting as template agents afford new supramolecular dinuclear complexes of podate type with terminal acetylpyridyl groups and N4O2, N5O2 or N6O2 set of donor atoms as a result of [2+1] Schiff base condensation. The complexes were characterized by spectral data (IR, 1 H NMR, FAB-MS), thermogravimetric and elemental analysis.
Keywords: Dinuclear complexes; Schiff base podates; Lanthanide complexes; Template synthesis;

The Schiff base 3-[N-2-(pyridylethyl)formimidoyl]salicylic acid (H2L) is a useful ligand for the design of heteronuclear complexes. A pentanuclear copper(II)–manganese(II) cluster was synthesized by using H2L as a ligand. The compound was characterised by analytical and spectral methods. Cryomagnetic investigations over the temperature range 1.9–300 K reveal antiferromagnetic interactions between the copper(II) and manganese(II) ions.
Keywords: Copper(II) complexes; Manganese(II) complexes; Magnetic properties; Schiff bases; Binucleating ligands;

A novel solid–liquid route for the preparation of Cu3Se2 and Ag2Se nanocrystals by Yu-lin Yan; Xue-feng Qian; Hong-jie Xu; Jie Yin; Zi-kang Zhu (34-37).
Cu3Se2 and Ag2Se nanocrystals have been synthesized with Se as the precursor in aqueous solutions under photo-irradiation at room temperature. The obtained products were analyzed through X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The results showed that the tetragonal phase of Cu3Se2 with nearly spherical grains and the orthorhombic phase of Ag2Se with nanoscale dendrite were formed. The experiments also confirmed that photo-irradiation and Na2SO3 played important roles in the formation of Cu3Se2 and Ag2Se nanocrystals. The formation mechanism of Cu3Se2 and Ag2Se nanocrystals was investigated in detail.
Keywords: Photo-irradiation; Solid–liquid synthetic route; Nanocrystals; Selenide;

One-pot template synthesis and crystal structure of two new polyaza copper(II) complexes by Yi He; Hui-Zhong Kou; Yong Li; Bei Chuan Zhou; Ming Xiong; Yadong Li (38-42).
A new 14-membered hexazamacrocyclic copper(II) complex [Cu(H2L1)](ClO4)4(L1=1,8-bis(2-aminoethyl)-1,3,6,8,10,13-hexaazacyclotetradecane) has been prepared by the one-pot reaction of ethylenediamine and formaldehyde in the presence of the Cu(II) ion. The crystal structure of [Cu(H2L1)](ClO4)4 was determined by X-ray diffraction. It crystallizes in the triclinic space group P−1 with a=12.118(2) Å, b=12.438(2) Å, c=12.466(2) Å, α=102.26(1)°, β=112.82(1)°, γ=111.51(1)°, and Z=2. The coordination geometry around the copper(II) ions is axially elongated octahedral with four nitrogen atoms of the macrocycle [Cu–N 2.012(7) Å for Cu(1) and 2.013(6) Å for Cu(2), average value] and two oxygen atoms of two ClO4 anions [Cu–O=2.550 Å for Cu(1) and 2.601(6) Å for Cu(2)]. [CuL2](ClO4)2(L2=3,7-bis(2-aminoethyl)-1,3,5,7-tetraazabicyclo[3,3,2]decane) with a novel tetraazabicyclic ligand was obtained from the same reaction system as an additional product. Crystal structure of [CuL2](ClO4)2: monoclinic space group Cc, a=16.393(3) Å, b=8.8640(18) Å, c= 13.085(3) Å, β=105.01(3)°, and Z=4.
Keywords: Crystal structures; Copper(II) complexes; Macrocyclic complexes; Polyaza ligands;

New multinuclear zinc complexes with N4O2 coordination spheres by David A. McMorran; Peter J. Steel (43-47).
The preparation and characterisation of the new, potentially octadentate, ligand 1,2,4,5-tetrakis(3-(2-pyridyl)pyrazol-1-ylmethyl)benzene ( L 2 ) is reported. This and two related ligands, 1,2-bis(3-(2-pyridyl)pyrazol-1-ylmethyl)benzene ( L 1 ) and hexakis(3-(2-pyridyl)pyrazol-1-ylmethyl)benzene ( L 3 ) were reacted with zinc(II) acetate to give complexes in which pairs of ligand arms chelate to Zn(OAc) units. The X-ray crystal structures of [Zn( L 1 )(OAc)]PF6 and [Zn 2( L 2 )(OAc)2](BPh 4)2 are reported.

Lanthanide metal complexes containing the first structurally characterized β-diketonate acid stabilized by hydrogen bonding by Claudio Pettinari; Fabio Marchetti; Augusto Cingolani; Andrei Drozdov; Sergei Troyanov; Ivan Timokhin; Vyacheslav Vertlib (48-51).
A series of {H3O+}[MQs 4] (M=Tb, Eu, Lu; HQs=1-phenyl-3-methyl-4-thenoylpyrazole-5-one) complexes have been prepared and characterized; the presence of the {H3O+} cation stabilized by H-bonding to the pyridinic nitrogen of Qs has been confirmed by X-ray and spectroscopic (NMR, IR) investigations.{H3O+}[MQs 4] (M=Tb, Eu, Lu; HQs= 1-phenyl-3-methyl-4-thenoylpyrazole-5-one) complexes have been prepared and characterized; the {H3O+} cation is stabilized by H-bonding to the pyridinic nitrogen of Qs.

Structure of a cavity-encapsulated nanodrop of water by Achim Müller; Hartmut Bögge; Ekkehard Diemann (52-53).
A (H2O)100 nanodrop of water was found in the cavity of a spherical polyoxomolybdate cluster of the type {(Mo)Mo5}12(spacer)30 and structurally characterised. The molecules within the water cluster are arranged in three concentric shells with radii of 3.84–4.04, 6.51–6.83 and 7.56–7.88 Å spanned by 20, 20, and 60 molecules, respectively. The first shell dodecahedron is formed exclusively by 20 hydrogen bonds (O⋯O=2.77–2.92 Å) in the centre and 12 (H2O)5 pentagons (O⋯O=2.66–2.81 Å) formed by hydrogen bonds at the periphery, i.e., the third shell. Each of the H2O molecules of the second (dodecahedral) shell connects the molecules from three different pentagons of the third shell with one molecule of the central dodecahedron.
Keywords: Water structure; Polymorphs of water/ice; Supramolecular H2O assemblies; Polyoxomolybdates;

The kinetics of the self-redox reaction of bis(R-dithiocarbonato)copper(II) complexes (R=Me, Et, i-Pr, i-Bu, 2-Bu, Oct) formed in situ by the mixing of water/alcohol solutions of Cu(II) salts and the corresponding alkali salts of the ligands are studied using stopped-flow spectrophotometric technique. It was found that: (i) maximal absorbance at 425 nm due to the studied complex is reached at Cu(II)/ligand ratio=1:2; (ii) reduction of Cu(II) to Cu(I) follows the kinetics of a second-order reaction in respect to the bis-chelate; (iii) the measured rate constants decrease with increasing the size of the remote ligand substituents; (iv) the rate constant depends on the type and the concentration of the alcohol in the solvent. The obtained results are discussed in terms of a self-redox reaction between Cu(II) and thiols proceeding within the associate between two bis(R-dithiocarbonato)copper(II) molecules without the formation of free radicals from the ligands.
Keywords: Kinetics and mechanism; Stopped-flow spectrometry; Copper complexes; Dithiocarbonato complexes;

The novel KBp i Pr2 and the previously described KTp i Pr2 react with [UI3(THF)4], in THF, yielding the new compounds [ U{κ 3 -Bp i Pr2 )}3 ] (1) and [ UI 2(κ 3 -Tp i Pr2 )(THF)x ] (x=2–3) (2), respectively. Compound 1 is remarkably stable, while 2 decomposes in solution, being the main decomposition product [ UI 2(κ 3 -Tp i Pr2 )(κ 1 -pz i Pr2 H)] (3). The formation of 3 is prevented when [UI3(THF)4] reacts with KTp i Pr2 in toluene, in the presence of strong neutral coordinating ligands.
Keywords: Uranium (III); 3,5-Diisopropylpyrazolylborates; Structural analysis;

First true square-planar Hg(II) compound: synthesis and full characterization of trans-[Hg{Ph2PNP(O)Ph2-P,O}2] by Rainer Haid; Rene Gutmann; Georg Czermak; Christoph Langes; Werner Oberhauser; Holger Kopacka; Karl-Hans Ongania; Peter Brüggeller (61-67).
The reaction of Hg(O3SCF3)2 with bis(diphenylphosphino)amine, Ph2PNHPPh2 (dppam), produces the novel, rare face-to-face complex [Hg2(O3SCF3)4(dppam)2] (1). Treatment of 1 with Na2N2O3 leads to trans-[Hg{Ph2PNP(O)Ph2-P,O}2] (2) via regioselective oxidation and simultaneous deprotonation of dppam. 2 is the first true square-planar Hg(II) compound. In 2 the coordination plane and the five-membered rings of the HgNOP2 moieties are completely coplanar indicating strong π-bonding interactions. Both 1 and 2 have been fully characterized by X-ray structure analyses, NMR spectroscopy (199 Hg{1 H},31 P{1 H},13 C{1 H},1 H), ESI and FAB mass spectrometry, IR spectroscopy, elemental analyses, and melting points. Since in Hg(II) compounds relativistic effects favour linear coordination and Hg(II) donor atom preferences play a significant role, the Hg–P bond length of 2.4042(7) Å in 2 is short, whereas the Hg–O bond length of 2.7138(15) Å is long. In view of the X-ray structures of 1 and 2, it is shown that the delocalized charge in [Ph2PNP(O)Ph2] is responsible for the achievement of the square-planar coordination in a Hg(II) compound. A similar π-bonding effect has been observed in several square-planar complexes of Pt(II), Pd(II), and Ni(II) containing cis-1,2-bis(diphenylphosphino)ethene (cis-dppen).
Keywords: Crystal structures; Mercury complexes; Square-planar mercury; Face-to-face complexes; Diphosphine complexes; Heterodifunctional ligands;

Nanocrystalline MoSe2 was prepared by a sonochemical reaction between Mo(CO)6 and Se in decalin at 273 K in nitrogen atmosphere. The products were characterized by X-ray powder diffraction (XRD), transmission electron microscope (TEM), energy-dispersive X-ray spectroscopy (EDXS) and thermal analysis (TG and DSC). The XRD patterns showed that the product is amorphous, while annealing at 330 °C yields nanocrystalline MoSe2. The influence of ultrasound and temperature is discussed.
Keywords: Sonochemical reaction; Selenides; Nanostructures;

Bis(N-carboxymethyl-N-(2-carbamoylmethyl)glycinato)copper(II) has been synthesised by reaction of Cu2(CO3)(OH)2 and N-(2-carbamoylmethyl)-iminodiacetic acid (H2ADA) in water. The new compound [Cu(HADA)2] (1) has been characterised by thermal, spectral, magnetic and X-ray diffraction methods. Its crystal structure was solved to a final value of R1=0.036. The crystal consists in a 3D hydrogen bonded network builds up by centro-symmetric molecules where the Cu(II) atom exhibits an elongated octahedral coordination. The ligand HADA adopts a fac-NO + O(apical amido) tridentate chelating conformation [Cu1–N1(amino)=2.063(2), Cu1–O31(carboxylato)=1.917(2), Cu1–O11(amido)=2.380(2) Å] and has a free N-carboxymethyl arm. A structural comparison between 1 and bis(N,N-bis(carboxymethyl)glycinato)copper(II) dihydrate (compound 2) reveals that the amide primary group is preferred to the unionised carboxyl group to form a Cu(II)–N, O-glycinamide-like chelate ring instead of a Cu(II)–N, O-glycine-like one. N-(2-carbamoylmethyl)-iminodiacetic acid (H2ADA) forms a copper(II) bis-chelate of formula [Cu(HADA)2] which consists in centro-symmetric molecules with two tridentate fac-N(amino),O(carboxylato) + O(apical amido)–HADA ligands, with a non-coordinated N-carboxymethyl arm. This finding represents a structural evidence of the preferential Cu(II)–O coordination for the –CONH2 group versus the –COOH one.
Keywords: Amide; Copper(II); N-(2-carbamoylmethyl)iminodiacetic acid; Acid bis-chelate; Crystal structure;

Bisphosphino ureas: flexible ligands with rigid backbone by Olaf Kühl; Walter Langel (74-77).
The nickel(0) complex [Ni{η 2-(PPh2NMe)2CO}{η 1-(PPh2NMe)2CO}] 1 was obtained by the reaction of NiCl2·6H2O with two equivalents of the ligand (PPh2NMe)2CO in the presence of zinc as reducing agent. The structure of 1 was unambiguously determined by 1H and 31P–{1H} NMR spectroscopy and compared to the known structures of the extremely strained Pd(II) and Mo(0) complexes of (PPh2NMe)2CO.

Rigidochromism in metal-centered emission of Rh(III) complexes by Leslie S. Forster; John V. Rund (78-81).
A thermally induced redshift in a metal-centered 3 T 1⇒1 A 1 emission is due to population of the higher energy component of 3 T 1 , split by a low symmetry field. The population of this level is increased by solvent motion and the redshift then appears as rigidochromism.

The reaction of copper powder in dmso with cadmium acetate hydrate and 2-dimethylaminoethanol (HL), in open air, afforded [Cd2Cu44-O)(O2CMe)6L4]·2H2O with a metal skeleton that approximates an octahedron. The copper atoms are tetrahedrally arranged about the oxygen atom in a considerably distorted fashion. The amino alkoxo and acetate ligands display a variety of bonding modes in the complex.
Keywords: Heterometallic complex; Zero-valent copper; 2-Dimethylaminoethanol; μ4-Bridging oxygen; Crystal structure;

Treatment of Ni(tsalen), where H2tsalen = bis(thiosalicylidene)imine with FeCl3 results in the isolation of a crystalline compound with the composition [BBITE2+][Ni(tsalen)]4[FeCl4 ]2 (I), where BBITE=1,2-bis(1,2-benzisothiazol-2-yl)ethane. The production of the BBITE2+ cation represents a 4-electron oxidation of the tsalen2− ligand, even though FeCl3 is not a strong enough oxidant to promote any outer-sphere oxidation of the Ni(tsalen) complex. The crystal structure of I shows a series of channels which are maintained by non-covalent interactions between the [Ni(tsalen)] and BBITE2+ molecules.
Keywords: Nickel complexes; Oxidation; Crystal structure; Heterocycles; Sulfur ligands;

Stability constants of metal ion complexes formed with N3-deprotonated uridine in aqueous solution by Bernd Knobloch; Carla P Da Costa; Wolfgang Linert; Helmut Sigel (90-93).
The acidity constant for the deprotonation of the (N3)H site of uridine (Urd) and the stability constants of the M(Urd–H)+ complexes with the metal ions M2+=Mg2+, Ca2+, Mn2+, Zn2+ or Cd2+ have been determined by potentiometric pH titrations in aqueous solution at 25 °C and I=0.1 M (NaNO3). The stability constant of the Pb(Urd–H)+ complex could not be measured due to the hydrolysis of Pb(aq)2+. It is shown that previously determined and compiled stability constants are far too large; the reason being most likely the neglect of M(aq)2+ hydrolysis, at least in the cases of Mn2+, Zn2+ and Cd2+. Because of the low stability of the alkaline earth ion complexes, it is suggested that in these instances outersphere species are formed which most likely also involve the C2 and/or C4 carbonyl oxygens of the uracil residue.
Keywords: Acidity constants; Metal complexes; N--metal binding; Outersphere complexes; Stability constants; Uridine;

Reactions of cyclic and linear alkynols with a phosphinic iron(II) centre by Ana I.F. Venâncio; Luı́sa M.D.R.S. Martins; João J.R. Fraústo da Silva; Armando J.L. Pombeiro (94-96).
Treatment of a MeOH solution of trans-[FeBr2(depe)2] (depe=Et2PCH2CH2PEt2) with HCCC6H10OH or HCC(CH2) n OH (n=1 or 2), in the presence of NaBPh4, forms the cyclic allenylidene trans-[FeBr(CCC6H10)(depe)2][BPh4] or the alkyne trans-[FeBr{η2-HCC(CH2) n OH}(depe)2][BPh4] (n=1 or 2) complexes, respectively.
Keywords: Iron; Alkynes; Allenylidenes; Alkynols; Propargyl alcohols; Phosphinic complexes;

An ion-pair complex [Cd(en)3]2 2+[Ag4(mnt)4]4− and three mixed metallic coordination polymers MNi(mnt)2 [M = Pd(II), 2Ag(I) or Hg(II); mnt2−=maleonitriledithiolate] have been prepared and characterized using IR, UV–Visible and conductivity techniques. All of the complexes exhibit pressed pellet σ rt ≃10−5   S cm −1 and show electrical behaviour of semiconductors over 303–393 K range.
Keywords: Mixed-metallic maleonitriledithiolate complexes; Solid phase conductivity; Semiconductors; UV–Visible spectra;

The development of new materials for the technological demands requires chemical routes, in the case of oxides mostly being sol–gel or CVD processing, for their elaboration. Those processes need metallic precursors with a set of ligands that are able to provide suitable properties such as solubility or volatility, clean decomposition pathways, control of stoichiometry for multimetallic arrays, to name but a few. These aspects will be illustrated on some recent examples of non-silicon systems.
Keywords: Oxoalkoxides; Functional alkoxides; Heterometallic alkoxides; Sol–gel; MOCVD;