Monomeric and Oligomeric Metal Selenide Complexes from Structural Transformation of the Tetraselenotungstate Anion

Abstract

Treatment of W(CO)6 with Na2Sex (x = 2–4) at 90 °C, prepared from heating selenium powder and sodium in DMF solution, afforded (Et4N)2[WSe4] (1) in a relatively high yield. Interaction of 1 with one equiv. [Me3NCH2Ph]Br in MeCN gave a cation exchanging product (Et4N)(Me3Ph2CH2N)[WSe4] (2) in a quantitative yield. Reaction of 1 with excess grey selenium in DMF produced monomeric polyselenide complex (Et4N)2[WO(Se4)2] (3). Treatment of 1 with equal equiv. anhydrous FeCl2 and excess PPh3 in DMF gave a dimeric complex (Fe(DMF)6)[W2Se4(μ-Se)2] (4). Similar reaction using MnCl2·4H2O salt easily gave rise to isolation of a trimeric complex (Mn(DMF)6)[WO(DMF)(μ-WSe4)2] (5). Reaction of 1 with anhydrous ZnCl2 in a mixed DMF/MeCN at 40 °C afforded a mixed-metal selenide complex (Et4N)2[Zn(μ-WSe4)2] (6). All complexes are well characterized by electronic, infrared, mass and NMR spectroscopies in this paper, and the solid-state structures of complexes 1–6 have been also established by X-ray crystallography. Interactions of tetraselenotungstate anion [WSe4]2− and first-row transition metal ions (Fe2+, Mn2+ and Zn2+) in the heating dimethylformide resulted in isolation of monomeric and oligomeric metal selenide complexes (Fe(DMF)6)[W2Se4(μ-Se)2] (Mn(DMF)6)[WO(DMF)(μ-WSe4)2] and (Et4N)2[Zn(μ-WSe4)2].