SCHEDULED MAINTENANCE
Transition metal dithiolene complexes. Part XVIII. Adducts of cobalt and iron bis-1,2-dithiolenes containing ethyldiphenylphosphine and bis(1,2-diphenylphosphino)ethane
Abstract
The syntheses and spectral characterisation of a series of adducts of iron and cobalt bis-1,2-dithiolenes with ethyldiphenylphosphine and bis(1,2-diphenylphosphino) ethane (diphos) are described. With PEtPh2, five-co-ordinate species of the type [M(PEtPh2)–(S–S)2]z were obtained, where z =–1 and (S–S)= S2C2(CN)2,S2C2(CF3)2 or S2C6Cl4, or where z = 0 and (S–S)= S2C2Ph2, S2C2(4-MeC6H4)2 or S2C2(4-MeOC6H4)2. With diphos, compounds of a similar type were prepared, viz.[M(diphos)–(S–S)2]z, where z =–1 or 0 and (S–S) was as shown above. By oxidation of the appropriate monoanion with iodine, [Fe(diphos){S2C2(CN)2}2]0 was prepared and isolated, and [Co(PEtPh2){S2C2(CF3)2}2]0 was identified by e.s.r. spectral measurements. Treatment of [Co(diphos)-{S2C2(4-MeOC6H4)2}2]0 with AgPF6 afforded the corresponding monocation, as the [PF6]– salt. The majority of the complexes underwent reversible one-electron transfer reactions indicating that they were members of the electron-transfer series [M(L)–(S–S)2]z where M = Fe or Co, L = PEtPh2 or diphos, and z=–2, –1, 0 or +1.
From the spectral and voltammetric data, it appears that in [M(diphos)–(S–S)2]z, when z=–1 and (S–S)= S2C2(CN)2 or S2C2(CF3)2, the diphosphine ligand is bidentate, but when z= 0 and (S–S)= S2C2Ph2, S2C2(4-MeC6H4)2 or S2C2(4-MeOC6H4)2, it may be monodentate.
Please wait while we load your content...
