Transtion-metal dithiolene complexes. Part XIV. Five-co-ordinate phosphine and phosphite adducts of cobalt and iron bis(diaryl-1,2-dithiolenes)

Abstract

The phosphine and phosphite adducts of cobalt and iron bis(diaryl-1,2-dithiolene), [M(PR3)(S2C2Ar2)2]0, (M = Co or Fe; R = Et, CH2CH2CN, Ph, OPh, or NMe2; Ar = Ph, 4-Me·C6H4, 2- 3- or 4- MeO·C6H4, 3,4-CH2O2C6H3, or 2,5-(MeO)2C6H3) have been prepared. The voltammetry of these complexes shown that they are part of at least a three- and possibly a four-membered electron transfer series, [M(PR3)(S2C2Ar2)2]z(z=+1, 0, –1, or –2. The half-wave potentials for the couple [M(PR3)(S2C2Ar2)2]z+ e–⇌[M(PR3)(S2C2Ar2)2]z-1 depend on the nature of the substituents R and Ar. [Co(PEt3){S2C2(4-MeO·C6H4)2}2] X (X = PF6 or BPh4)[Co{P(NMe2)3}{S2C2(4-Me.C6H4)2}2][BPh4] and [Bun4N][Co{P(CH2CH2CN)3}S2 C2Ph2)2] have been isolated and characterised, and there is spectral evidence for [Fe{P(NMe2)3}{S2C2(4MeO.C6H4)2}2]+, [Fe{P(CH2CH2CN)3}S2C2Ph2)2]– and [Fe{P(OPh)3}(S2C2Ph2)2]–.