Dimeric tungsten(V) compounds containing [(S)W(µ-S)2W(S)]2+. Syntheses and structures of di-µ-sulphido-bis[(diethyl dithiophosphato-SS′)sulphido-tungsten(V)] and di-µ-sulphido-bis[(N,N-diethyldithiocarbamato-SS′)-sulphidotungsten(V)]

Abstract

The compound [W₂S₄{S₂P(OEt)₂}₂] has been isolated by two alternative routes: (a) treatment of [WS₄]^2– with HS₂P(OEt)₂ and (b) reaction of WS₂Cl₂ with [NH₄][S₂P(OEt)₂]. The oxidation product of both reactions is [(EtO)₂P(S)S–]₂. The two routes led to two different crystal forms, (1a) and (1 b), of the product [W₂S₄{S₂P(OEt)₂}₂]. Treating [W₂S₄{S₂P(OEt)₂}₂], either form, with Na(S₂CNEt₂) gave [W₂S₄(S₂CNEt₂)₂](2). The crystal structures of (1a), (1b), and (2) have been determined. (1a) is monoclinic, space group P2₁/n, with a= 18.230(11), b= 12.905(11), c= 10.153(12)Å, β= 90.5(1)° and Z= 4; (1b) is monoclinic, space group P2₁/a, with a= 13.844(12), b= 10.280(9), c= 17.907(13)Å, β= 113.2(1)°, and Z= 4; (2) is orthorhombic, space group P2₁2₁2₁, with a= 13.80(1), b= 10.49(1), c= 14.59(1)Å, and Z= 4. Diffractometer data were collected for all three compounds [independent reflections above background, 5 787 (1a), 3 658 (1b), and 2 134 (2)], the structures determined by the heavy-atom method and refined to give R= 0.061, 0.084, and 0.066 for (1a), (1b), and (2) respectively. All three compounds contain the syn form of [(S)W(µ-S)₂W(S)]²⁺{bond length ranges 2.054(12)–2.116(5)[W–S(terminal)], 2.279(8)–2.325(9)[W–S(bridging)], and 2.795(2)–2.819(1)Å(W–W)}. In addition to the bonds in the [W₂S₄]²⁺ moiety, each tungsten atom is co-ordinated to a bidentate ligand with W–S bond lengths in the range 2.429(9)–2.498(6)Å. Apart from the W–W bond each metal atom is five-co-ordinate and has a distorted square-pyramidal structure.