A. V. Rogachev

Hexanuclear chloride and brimode tungsten clusters and their derivatives

Several hexanuclear chloride and bromide bridged tungsten clusters have been prepared. Two new oxo-bridged clusters, Na[W6OBr18] and [α-W6(μ2-OH)4(μ2-O)6(μ2-Cl)2Cl6]2− are reported. Crystal structures of eight new tungsten cluster complexes with different core types were determined. The possibility of Se for Cl substitution in the {W6Cl8}4+ core was investigated.

Crystal structure of two polymorphic modifications of NbS2Br2 niobium thiobromide

The crystal structures of triclinic and monoclinic modifications of Nb thiobromide NbS2Br2 are determined by X-ray analysis. Both modifications possess layered structures in which {Nb2(μ-S2)2}4+ cluster units are connected by bridging bromides into 2D layers ∞2[Nb2(S2)2Br8/2]. The two polymorphs differ only in the way in which the layers are stacked. Interatomic distances and bond angles are identical for both polymorphs.

Synthesis of Im3[Mo3(μ3-S)(μ-S2)3Br6]Br (Im = 1-ethyl-3-methylimidazolium) in Ionic Liquid: A New Way of Breaking Up Chalcogenide Cluster Coordination Polymers

Abstract Reaction of 1D cluster coordination polymer Mo3S7Br4 with an ionic liquid composed of 1-ethyl-3-methylimidazolium bromide (ImBr) and AlBr3 in 2:1 molar ratio affords Im3[Mo3(μ3-S)(μ-S2)3Br6]Br (1) in high yield. X-ray structure of 1·CH3CN is reported.Graphical Abstract

Xanthate complexes of {Nb2S4}4+

Alkyl xanthate complexes [Nb2S4(S2COR)4] (R = Et (I), iso-Pr (II), n-Bu (III), and iso-Am (IV)) are synthesized by the ligand exchange reaction in solutions from (Et4N)4[Nb2S4(NCS)8] and the corresponding potassium salts in satisfactory yields. The X-ray diffraction analyses are carried out for the isopropyl xanthate (II) and butyl xanthate (III) complexes. From the view point of mutual arrangement of chelate cycles, complexes II and III exist in crystals as ΛΔ isomers. The niobium-niobium distances are 2.8789(4) Å in complex II and 2.8856(3) Å in complex III. The first example for the formation of short S...S contacts between the disulfide ligands of the {Nb2S4}4+ fragments in the crystal structure of III is found (3.146 Å).

Crystal structure of two salts derived from paratungstate in the [H2W12O42]10− anion

Novel mixed salts of the paratungstate anion Na2(NH4)8[H2W12O42]·12H2O (1) and Na7.5K2.5[H2W12O42]··22.2H2O (2) are obtained by slow concentration of tungstate solutions and characterized by single crystal X-ray diffraction.

Reaction of [VO(OPr)3] with hexamethyldisylthiane in the presence of β-diketones

The reaction of [VO(OPr)3] (Pr is n-propyl) with hexamethyldisylthiane Me3SiSSiMe3 in the presence of β-diketones (acetylacetone (HAcac), hexafluoroacetylacetone (Hfac), and dipivaloylmethane (Dpm)), is studied. In all cases, vanadium(IV) and vanadium(III) β-diketonate complexes of different types are formed. New crystalline modification [V(Acac)3] is obtained in the reaction with HAcac. The mixedligand vanadium(III) complex of the composition [V2(Hfac)2(μ-OPr)]2 is formed with Hfac. In the presence of Dpm, the known vanadium(IV) complex [V2O2(Dpm)2(μ-OPr)2] is obtained in which two vanadyl groups VO2+ are linked by two bridging propoxy groups. The structures of all products are determined by X-ray diffraction analysis.

Vanadium(III) dithiophosphate complex [V(S2P(O-iso-Pr)2)3]: synthesis and structure

The reaction of [VO(OPr)3] with (iso-PrO)2P(S)SH (Pr is n-propyl, and iso-Pr is isopropyl) followed by the treatment with hexamethyldisilthiane (Me3SiSSiMe3) affords the vanadium(III) dithiophosphate complex [V(S2P(O-iso-Pr)2)3]. The structure of the complex is determined by X-ray diffraction analysis (CIF file CCDC 986354).

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.

Crystal Structure of Tl2[NbCl6] and Tl2[NbBr6]

Single crystals of Tl2[NbCl6] (1) and Tl2 [NbBr6] (2) are obtained as black needles on heating TlCl, Nb, S2Cl2 (1) and Tl, Nb, and Br2 at 400°C (2). Tl2NbBr6 also forms in the reaction of TlBr, Nb, Br2, and S at 500°C. Both compounds crystallize in the K2[PtCl6] structure type to form non-distorted octahedral [NbХ6]2– anions (Nb–Cl 2.397(4) Å and Nb–Br 2.516(2) Å). The magnetic properties of Tl2[NbBr6] in a range 5-300 K indicate an antiferromagnetic interaction between Nb4+ ion spins (d1, S = 1/2). On cooling, the compound becomes a noncollinear ferromagnet with Tc = 23 K.

Tantalum Dimethyldithiocarbamate Complexes

The reaction of Ta(NMe2)5 with CS2 gave the tantalum(V) dimethyldithiocarbamate complex [Ta(MeDtc)4](MeDtc) (I). An ionic structure of the complex with a dodecahedral coordination of the tantalum atom was determined for toluene (I · Tol) and THF (I · THF) solvates by X-ray diffraction (CCDC no. 1544283 and no. 1544284, respectively). The reaction of I with CH2Cl2 leads to exchange of the outersphere anion to give the known complex [Ta(MeDtc)4]Cl (II). The cyclic voltammogram of II in CH3CN exhibits a quasi-reversible transition at E1/2 =–0.735 V corresponding to the TaV/TaIV pair.