Vanadium(IV) and oxidovanadium(IV) and -(V) complexes with soft thioether coordination - Synthesis, spectroscopic and structural studies

VOCl3 reacts with the thioethers RS(CH2)(2)SR (R = Me, Et or iPr) and 1,4-dithiane to form the first examples of V-v thioether complexes, the highly reactive, intensely coloured [VOCl3(dithioether)] which have been characterised by H-1 and V-51 NMR, IR and UV/Vis spectroscopy. Combining VOCl3 with [9]aneS(3) gives [VOCl3(kappa(2)-[9]aneS(3))] which, upon treatment with SbCl5 gives [VOCl2 (kappa(3)-[9]aneS(3))][SbCl6]. Vanadium K-edge extended X-ray absorption fine structure (EXAFS) studies on three examples provided partial structural analyses for these very unstable compounds. Reaction of VCl4 with O(SiMe3)(2) in CH2Cl2/MeCN followed by addition of RS(CH2)(2)SR (R = Me or Et) produced [VOCl2{RS(CH2)(2)SR)]. The crystal structure Of [{VOCl2- (MeSCH2CH2SMe)}(4)] reveals a unique tetrameric V4O4 core with each vanadium also coordinated to a chelating dithioether and two Cl ligands to complete the distorted octahedral geometry. Under rigorously anhydrous conditions VCl4 reacts with RS(CH2)(2)SR (R = Me, Et, iPr, Ph), 1,4-dithiane or [9]aneS(3) to form [VCl4(thioether)] which are assigned as six-coordinate distorted octahedral species on the basis of their spectroscopic characterisation. In some cases trace hydrolysis of these compounds provides an alternative route to the [VOCl2(dithioether)] complexes. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007).