A. L. Gushchin

First heteroleptic Mo3S7 clusters containing non-innocent phenanthroline ligands

Reaction of the thiobromide [Mo3S7Br6]2− cluster anion with 5,6-dimethyl-1,10-phenanthroline (Me2Phen) in solution leads to the substitution of two bromide ligands and the subsequent formation of a new mixed-ligand neutral complex [Mo3S7Br4(Me2Phen)] (I). Reaction of [Mo3S7Br6]2− with 5,6-dimethyl-1,10-phenanthroline in CH2Cl2 followed by treatment of I with Na(Dtc) · 3H2O (Dtc = diethyldithiocarbamate) results in the new mixed-ligand cluster complex [Mo3S7(Dtc)2(Me2Phen)]2+ (IIa). Slow evaporation of the CHCl3 solution of the complex in the presence of PF6− gives crystals of {[Mo3S7(Dtc)2(Me2Phen)]Br}PF6 · 3CHCl3 (II) characterized by X-ray structural analysis. Close contacts S...S result in the formation of cationic dimers {[Mo3S7(Dtc)2(Me2Phen)]2}4+ which form infinite chains through additional Sax...Br contacts. All compounds were characterized by IR, elemental analysis and ESI-MS. Synthesized complexes represent the first examples of heteroleptic Mo3S7 clusters containing phenanthroline ligands.

Mixed-ligand cluster [Mo 3 S 4 (Dtp) 2 (μ-AcO)Cl(Me 2 Bipy)]: Synthesis and structure

Mixed-ligand cluster [Mo3S4(Dtp)2(μ-AcO)Cl(Me2Bipy)] · CHCl3 (I · CHCl3), where Dtp is (EtO)2PS2, was synthesized by the reaction of the molybdenum aqua complex [Mo3S4(H2O)9]4+ with 4,4′-dimethyl-2,2′-bipyridine (Me2Bipy) and phosphorus sulfide (P4S10) in ethanol followed by chromatographic separation on silica gel and crystallization in the presence of acetic acid. The crystal structure of I · CHCl3 was determined by X-ray diffraction analysis. The synthesized compound was characterized by the IR and NMR spectra and elemental analysis. The electronic structure of the synthesized compound was established, and its electrochemical behavior in a solution was studied.

Binuclear cluster complexes of molybdenum containing 2,2′-bipyridine and 1,10-phenanthroline: Synthesis and structure

By the interaction between (Et4N)2[Mo2O2S8] and I2 in DMF with a subsequent addition of 2,2′-bipyridine or 1,10-phenanthroline, new binuclear complexes [Mo2O2S2I2(bipy)2] (1) and [Mo2O2S2I2(phen)2] (2) are obtained. The structure of [Mo2O2S2I2(bipy)2] is determined using single crystal X-ray diffraction. The compounds are characterized by elemental analysis and IR spectra. The [MoO(S2)2(bipy)] complex as a product of oxidative destruction of 1 is isolated and characterized.

Structure and thermal properties of a tungsten sulfide cluster with thiourea ligands

The reaction of [W3S4(H2O)9]4+ with thiourea (tu) in hydrochloric acid produces a new cluster complex [W3S4(tu)8(H2O)]Cl4∙2H2O containing coordinated thiourea. The complex is characterized by elemental analysis, thermogravimetry, IR, NMR, UV-Vis spectroscopy, and mass spectrometry. The crystal structure is determined by X-ray analysis. The thermal decomposition of [W3S4(tu)8(H2O)]Cl4∙2H2O on heating from 20°С to 700°С in He gives WS2, identified by the X-ray diffraction pattern. DFT calculations for [W3S4(tu)8(H2O)]4+ show that HOMO has a comparable contribution from metal- and ligand-centered atomic orbitals.

Tosylate cluster complexes (Bu4N)2[М6I8(O3SC6H4CH3)6] (M = Mo, W)

The reaction of (Bu4N)2[М6I14] with silver p-toluenesulfonate (tosylate) AgO3SC6H4CH3 affords iodide cluster complexes (Bu4N)2[М6I8(Рts)6] (М = Mo (I), W (II); Рts is tosylate anion CH3C6H4SO3). According to the X-ray diffraction data (СIF file CCDC no. 1027969), the molybdenum atoms in (Bu4N)2[Мo6I8(Рts)6] · 2Et2O · 2MeCN (I′) are coordinated via the monodentate mode by the tosylate ligands. The 1H NMR and mass spectrometry data show that in donor solvents the complexes undergo solvolysis followed by the substitution of the tosylate ligands by the solvent molecules, which is accompanied by changes in the electrochemical properties, as shown by the cyclic voltammetry data.

X-ray emission study of the electronic structure of binuclear niobium complexes with (S 2 ) 2 –disulfide bridging ligands

The electronic structure of binuclear niobium complexes [Nb2S4(acac)4] and K4[Nb2S4(ox)4] is studied by X-ray emission fluorescent spectroscopy and quantum chemistry techniques. Data on the partial atomic composition of highest occupied molecular orbitals of the complexes are obtained. The energy positions of bonding and antibonding frontier molecular orbitals observed in the X-ray emission spectra of binuclear [Nb2((S2)2–)2]4+ clusters are determined by the analysis of overlap populations.

Crystal structure and EPR spectra of (Bu 4 N) 2 [V(dmit) 3 ]

The tris-chelate complex of vanadium(IV) (Bu4N)2[V(dmit)3] is prepared from VCl3 and (Bu4N)2[Zn(dmit)2] (dmit = isotrithionedithiolate C3S52–) and characterized by single crystal XRD and mass spectrometry. The complex crystallizes in the space group Pna21 and has a distorted octahedral environment of vanadium. The complex is paramagnetic and gives a characteristic EPR spectrum in both solution and solid phase. The g factors and hyperfine interaction constants are determined.

Synthesis and crystal structure of the binuclear complex Cs3[Mo2VO2(μ-S)2Cl4(H2O)2]Cl

The destruction of hydroxy and aqua bridges of the cyclic pentamer K2I2[Mo10O10(μ-S)10(OH)10(H2O)5] · 20H2O (I) in HCl in the presence of CsCl gave a new binuclear oxothiomolybdenic complex Cs3[Mo2O2(μ-S)2Cl4(H2O)2]Cl (II), which was isolated and characterized by X-ray crystallography. The dimeric fragment in complex II consists of two distorted octahedral Mo(V) centers, which have non-equivalent environment and are connected by two sulfide bridges. The Mo-Mo distance (2.8411(6) Å) in II corresponds to a metal-metal bond.

Telluride clusters of molybdenum: Synthesis, structures, and NMR spectra

High-temperature reactions of Mo, chalcogen (S or Se), Te, and Br2 in molar ratio Mo: S/Se: Te: Br = 3: 1: 6: 4 were carried out. The reaction products were subjected to mechanochemical activation with K(Dtp) (Dtp = (EtO)2PS2) in a vibrational mill, resulting in the formation of new compounds [Mo3(μ3-Q)0.5(μ3-O)0.5(μ2-Te2)3(Dtp)3](Dtp) (Q = Se (I) and S (II)). The structure of compound I has been established by X-ray diffraction analysis. Solutions of compounds I and II contain mixtures of [Mo3(μ3-Q)(μ2-Te2)3(Dtp)3]+ and [Mo3(μ3-O)(μ2-Te2)3(Dtp)3]+, which is confirmed by mass spectrometry and 31P, 77Se, and 125Te NMR spectroscopy. Quantum-chemical calculations of the 125Te NMR chemical shifts were performed. The compounds are also characterized by IR spectroscopy, Raman spectroscopy, and elemental analysis. Structure I contains short nonvalent contacts between the sulfur atom of the out-of-sphere Dtp anion and the axial tellurium atoms of the cluster.

Cubane pyridine-acetylacetonate cluster complexes with the M3CuS45+ core (M = Mo, W)

The reactions between [Mo3(μ3-S)(μ2-S)3(Acac)3(Py)3]PF6 (HAcac is acetylacetone, Py is pyridine) and CuX (X = Cl, I, SCN) afford heterometallic cubane clusters [Mo3(CuX)(μ3-S)4(Acac)3(Py)3]PF6. The structures of two new compounds, [Mo3(CuCl)S4(Acac)3(Py)3]PF6 · 3.25CH2Cl2 · 0.5C6H5CH3 and [Mo3(CuI)S4(Acac)3(Py)3]PF6 · 4C6H6, are determined by X-ray diffraction analysis. All synthesized compounds are characterized by elemental analysis and IR spectra. According to the vibrational spectra, the thiocyanate complex in the solid state is a mixture of the bond isomers [Mo3(CuNCS)S4(Acac)3(Py)3]PF6 and [Mo3(CuSCN)S4(Acac)3(Py)3]PF6, whereas in solution this complex exists as a isothiocyanate form.