N. V. Podberezskaya

Synthesis and crystal structure of a hexanuclear rhenium cluster complex Cs3K[Re6(μ3-S)6 (μ3-Te0.66S0.34)2(CN)6]. Cationic control over orientation of the cluster anion

Abstract The hexanuclear complex rhenium salt Cs3K[Re6(μ3-S)6(μ3-Te0.66S0.34)2(CN)6] ({Bd1}) has been prepared by the reaction of Re6Te15 with molten KSCN and subsequent treatment with an aqueous solution of CsCl. Its crystal structure has been determined by X-ray structural analysis. The anion has the site symmetry 3 . The Re6 octahedron is coordinated to six μ3-S and two trans mixed μ3-X ligands of the refined composition 66(3)%Te+34(3)%S. In addition there are six almost linear terminal CN ligands in its environment. The ReRe distances [2.630(2) A] in the Re3 faces capped by the μ3-X ligands are significantly longer than those in the faces capped by the μ3-S ligands [2.615(2) A].

Triangular M3Se74+ and M3Se44+ complexes (M = Mo, W). An X-ray study of Mo3Se7(Et2NCS2)4 and W3Se7(Et2NCS2)4

Abstract New methods for the synthesis of triangular M 3 Se 7 4+ and M 3 Se 4 4+ complexes soluble in organic solvents have been developed which proceed from polymeric M 3 Se 7 X 4 (M = Mo, W; X = Cl, Br). Heating of Mo 3 Se 7 Cl 4 in a PPh 4 Cl melt has produced the (PPh 4 ) 2 Mo 3 Se 7 Cl 6 salt. Selenobromide complexes of molybdenum and tungsten are less stable and have been converted to M 3 Se 7 (dtc) 4 complexes by reacting them with NaS 2 NCEt 2 ·3H 2 O (Nadtc·3H 2 O) in CH 3 CN. The structure of M 3 Se 7 (dtc) 4 (M = Mo, W) has been determined by X-ray structural analysis: a = 16.728(5), b =18.604(7), c =13.324(3) A, β=99.12(3)°, Z =4, P 2 1 / c , R F =0.1344 for W 3 Se 7 (dtc) 4 ; a =16.652(5), b =18.614(8), c =13.337(3) A, β=99.11(2)°, Z =4, P 2 1 / c , R F =0.0628 for Mo 3 Se 7 (dtc) 4 . Heating of M 3 Se 7 X 4 in a melt of 1,10- phenanthroline (phen) produces salts containing M 3 Se 7 (phen) 3 4+ with different anions (Cl − , Br − , ZnCl 4 2− , ZnBr 4 2− ). The action of phosphines on M 3 Se 7 4+ complexes gave M 3 Se 7 4+ complexes Mo 3 Se 4 (dtc) 4 (PPh 3 ) and Mo 3 Se 4 (dppe) 3 Cl 4 (dppe is Ph 2 PCH 2 CH 2 PPh 2 ).

Crystal Chemistry of Dichalcogenides MX2

Crystal-chemical analysis of the structures of metal (other than REE) dichalcogenides of composition X:M = 2:1 has been carried out. It is shown that there are two types of structure depending on the formal degree of metal oxidation. The first group are compounds M(X2) containing metals in the oxidation state 2+ and covalently bonded pairs of chalcogen elements; the main structural types here are cubic (pyrite) and orthorhombic (marcasite) FeS2. The second group involves the compounds MX2 with metals in the formal oxidation state 4+ and chalcogenide ions X2-; the main structural types in this group are CdI2, CdCl2, MoS2. The bond lengths M–X, X–X, and X...X are analyzed; it is shown that the high polarizability of the chalcogenide ions is reflected in shortened X...X distances. In the covalently bonded pairs X–X, the bond lengths change within the following limits: 2.03-2.30, 2.35-2.55, and 2.70-2.83 Å for X...X ion contacts, the minimal values are 3.07, 3.10, and 3.20 Å (X = S, Se, and Te, respectively).

New efficient synthesis of the triangular cluster [W3Se4(H2O)9]4+ and X-ray structure of the first mixed-metal seleno-bridged cubane-type tungsten-tin cluster (Me2NH2)6[(SCN)9W3Se4SnCl3]·0.5H2O

Abstract The trinuclear incomplete cuboidal [W 3 Se 4 (H 2 O) 9 ] 4+ cluster has been prepared by reacting polymeric solid W 3 Se 7 Br 4 with H 3 PO 2 in aqueous HCl solution with yields up to 50%. The mixed-metal cluster compound (Me 2 NH 2 ) 6 [(SCN) 9 W 3 Se 4 SnCl 3 ]·0.5H 2 O ( 1 ) has been prepared by reacting [W 3 Se 4 (H 2 O) 9 ] 4+ in aqueous HCl solution with SnCl 2 ·2H 2 O in the presence of Me 2 NH 2 Cl and NaSCN. Crystals of 1 are monoclinic, space group C 2/ c , a = 42.868(6), b = 12.035(1), c = 21.976(5)A, β = 95.69(1)° and Z = 8. The structure was refined by full-matrix least-squares techniques to R ( Rw ) = 0.0343(0.04778). The title compound 1 is the first mixed-metal seleno-bridged cubane-type tungsten-tin cluster as derivative of [W 3 Se 4 (H 2 O) 9 ] 4+ .

Synthesis and x-ray crystal structure of new complex trans-dinitrodiaqua-bis (1-phenyltetrazole) copper(II)

Abstract A new complex CuL2(NO3)2(H2O)2 (L = 1-phenyltetrazole) was synthesized and characterized by X-ray crystallography. The coordination polyhedron of Cu has the form of an elongated square bipyramid with site symmetry 1 . Two L ligands (by N4 donor atoms) and two water molecules are trans-coordinated to copper in the equatorial plane (Cu—N = 1.990(3), Cu—O = 1.984(3) A). The oxygen atom sof two NO−3 ions occupy axial positions (Cu—O = 2.403(3) A). The angle between the tetrazole plane and the Ph group is 4.07°.

Diethyldithiocarbamate triangular thio complexes of molybdenum : synthesis and an X-ray structural study of [Mo3S7(S2CNEt2)3]Cl

Abstract Heating of Mo3S7(S2CNEt2)4 (1) in 1,2-dichloroethane has afforded the [Mo3S7(S2CNEt2)3]Cl (2) complex which was characterized by elemental analysis, IR, Raman and PMR data. The structure of 2 was established by X-ray structural analysis. The average MoMo distance is 2.721(2) A, and the S-S distance of the μ2-S2 ligand is 2.041(6) A. The outer sphere chlorine atom is separated from the axial sulfurs of the μ2-S2 ligands by 2.97–3.05 A. Complexes 1 and 2 are 1:1 electrolytes in DMF (1) and in 1,2-dichloroethane (2).

Synthesis and x-ray structure of the triangular Cluster (Et4N){[Mo3(μ3-S)(μ2-S2)3(NH2Ph)3Br3]br}br

Abstract The complex of the formula (Et 4 N)Mo 3 S 7 Br 5 (NH 2 Ph) 3 ( 1 ) has been prepared by interacting (Et 4 N) 2 Mo 3 S 7 Br 6 with aniline. The crystal structure has been determined. The [Mo 3 S 7 (NH 2 Ph) 3 Br 3 ] cation and two bromine anions form the ionic trimer due to the interaction of S⋯Br (2.93–3.32 A) with three axial and one equatorial sulphur atoms of the μ 2 -S 2 ligands.

The first x-ray study of a W3Se44+ complex: An unexpected dimerization of high-charged anionic clusters, W3Se4(NCS)5−9, in the crystal of its trimethylammonium salt

Abstract The W3Se44+ ion has been obtained and the crystal structure of (Me3NH)5W3Se4(NCS)9 was determined, in which unexpected dimerization of the anions by short Se—Se contacts was observed.

Metal substitution reaction in the cluster [(μ−H)2Fe3(μ3−Se)(CO)9]. Crystal and molecular structure of [(μ−H)Fe2W(μ3−Se)(CO)8(η5−C5H5)]

Abstract The cluster [(μ−H)2Fe3(μ3−Se)(CO)9] has been found to react with [CPW(CO)3]2 [Cp = (η5−C5H5)] when refluxed in m-xylene. Two major products of this reaction have been isolated, one of which is the heteronuclear cluster [(μ−H)Fe2W(μ3−Se)(CO)8Cp]. Its structure has been determined by X-ray analysis. The other product is probably [FeW2(μ3−Se)(CO)7Cp2]. Its composition and structure have been proposed from the IR, 1H and 77Se NMR spectra and the C,H elemental analysis data.

Synthesis and crystal structure of [Mo3(μ3-S)(μ-SSe)3(dtc)3]SeCN. An example of formation of unusual polymeric chains by cation and anion chalcogen atoms

Abstract The interaction of [Mo3S7(dtc)3]dtc with KSeCN gives the [Mo3S4Se3(dtc)3] SeCN-salt (1) in 74% yield. The X-ray structure of 1 was determined. The [Mo3S4Se3(dtc)3]+ cation has the usual geometry, selected distances being 2.72(1)–2.73(1) A for Mo Mo, 2.16(3)–2.23(3) A for SSe. The characteristic feature of structure 1 is the formation of rather short (2.9–3.3 A) cation-anion contacts between the sulphur and selenium atoms of the μ2-SSe ligand and the selenium atom of the SeCN− counter-ion. This results in the formation of practically linear polymeric chains, SSe· Se·SSe· SSe·. The treatment of the (Ph4P)2W3S7Br6 cluster with KSeCN and NaSCN yields the complex (Ph4P)2W3S4Se3(NCS)6 in 39% yield.