Transition-metal dithiolene complexes. Part XV. π-Cyclopentadienyl nitrosyl and related molybdenum complexes

Abstract

The reactions between [{(π-C₅H₅)Mo(NO)I₂}₂] and disodium cis-dicyanoethylene-dithiolate, disodium tetrachlorobenzene-1,2-dithiolate, toluene-3,4-dithiol, and bis(trifluoromethyl) dithieten proceed in stages. A variety of complexes, of the type [(π-C₅H₅)Mo(NO)–(S–S)]₂, [(π-C₅H₅)Mo(NO)(I)–(S–S)],^–[(π-C₅H₅)Mo–(S–S)]₂-, and [Mo–(S–S)₃]^2–, where S–S represents the bidentate dithiolato-ligand, have been isolated. With disodium dicyanoethylene-2,2-dithiolate and NaS₂CNR₂(R = Me or Et), only [(π-C₅H₅)Mo(NO)(I)S₂C:C(CN)₂]^– and [(π-C₅H₅)Mo(NO)(I)S₂CNR₂], respectively, were isolated; the proton magnetic resonance spectra of the latter indicated that the molybdenum atom was an asymmetric centre and that there was considerable multiple-bond character in the S₂C–NR₂ link. Treatment of [{(π-C₅H₅)Mo(NO)S₂C₂(CN)₂}₂] in solution with triphenyl phosphite afforded [(π-C₅H₅)Mo(NO){P(OPh)₃}S₂C₂(CN)₂]. A voltammetric examination of the complexes revealed that all species, except the dimers, could be oxidised in a one-electron step, but only [Mo(S₂C₆Cl₄)₃]^– was synthesised.