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Eight‐coordinated 1,1‐dithio ligand complexes of molybdenum and tungsten

1976; Royal Netherlands Chemical Society; Volume: 95; Issue: 10 Linguagem: Inglês

10.1002/recl.19760951010

1878-7096

A. Nieuwpoort, J. J. Steggerda,

Corrosion Behavior and Inhibition

Abstract The physical properties of the dithiocarbamato compounds Mo(R 2 dtc) 4 (R 2 dtc = R 2 NCS 2 − ; R = Me, Et, i ‐Pr, Bz, Ph; R 2 = Tm, Pm, MeBz; Tm = (CH 2 ) 4 , Pm = (CH 2 ) 5 ) and [M(R 2 dtc) 4 ]X (M = Mo, W; X = various anions), and the dithio acid compounds M(Rdta) 4 (M = Mo, W; Rdta = RCS 2 − ; R = Tol, Naf; Tol = p ‐toluoyl, Naf = 2‐naphthoyl), prepared by oxidative decarbonylation of metal carbonyl complexes with disulfides, have been investigated. Conductivity data and infrared spectra indicate that all compounds contain metal ions coordinated by eight sulfur atoms belonging to four ligands. Voltammetric measurements show for the [Mo(R 2 dtc) 4 ]° ,+ complexes three one‐electron oxidation/reductions, indicating the formation in solution of unstable [Mo(R 2 dtc) 4 ] − and [Mo(R 2 dtc) 4 ] 2+ . The [W(R 2 dtc) 4 ] + complexes show only one oxidation and one reduction process in the voltage range studied. The substituent effects on the half‐wave potentials can be described by the Taft relation. The dithio acid complexes show two redox processes, indicating the formation of M(II) and M(V) compounds. The differences between these complexes and the dithiocarbamato complexes are in agreement with the stronger electron donating properties of the dtc ligand.