Crystallographic evidence for the coordination performance of WO_2S_2~(2-). Synthesis, characterization and crystal structure of palladium complexes, with mixed-ligand thiotungstates and 1,2-dithiolates: [NBu_4]_2[PdWO_2S_2(C_3S_5)] and [NBu_4]_2[PdW

摘要

Two novel palladium complexes derived from thiotungstates and 1,2-dithiolates, [NBu_4]_2[PdWO_2S_2(dmit)] (1) and [NBu_4]_2[PdWS_4(mnt)] (2) (H_2dmit = 4,5-dimercapto-1,3-dithiole-2-thione, H_2mnt = 2,3-dimercapto-2-butenedinitrile), have been synthesized and characterized. X-ray diffraction analyses reveal that palladium in 1 is coordinated by a dmit (C_3S_5~(2-)) and a dioxothiotungstate (WO_2S_2~(2-)), whilst in 2 it is coordinated by a nmt (C_4N_2S_2~(2-)) and a tetrathiotungstate (WS_4~(2-)). 1 is the first structurally determined metal complex with dioxothiotungstate as ligand. Both dithiolates and thiotungstates in 1 and 2 play the role of bidentate ligands though two sulfur atoms chelating palladium atoms. The Pd-W distances are 2.917(1) and 2.986(1) A in 1 and 2, respectively. The electronic properties have been investigated by spectroscopic techniques and cyclic voltammetry. The reaction of 2 with Ag(Ph_3P)_2NO_3 affords Pd(Ph_3P)_2(mnt) and Ag_4W_2S_8(Ph_3P)_4.