Coordination behaviour of (diaryl disulfide)-bridged dinuclear thiairidaindan cores: ligand substitution by isocyanides, CO, hydrazines and hydroxylamine, and related reactions

The diaryl disulfide ligand in the thiolato-bridged diiridium(III) complexes [{Ir(mu-SC6H4 - nMe(n)CH(2))Cl(PPh3)}(2)-(mu-ArSSAr)] [1a, n = 1, Ar = C6H3Me2-2,6 (Xy); 1b, n = 2, Ar = C6H2Me3-2,4,6 (Mes)] is readily substituted by isocyanides, CO, hydroxylamine and hydrazines to afford the bis(isocyanide), bis( carbonyl) and bis( hydroxylamine) complexes [Ir(mu-SC6H4 (-) nMenCH2)Cl(PPh3)(L)](2) (2a, n = 1, L = XyNC; 2b, n = 2, L = XyNC; 3a, n = 1, L = (BuNC)-N-t; 3b, n = 2, L = (BuNC)-N-t; 4a, n = 1, L = CO; 4b, n = 2, L = CO; 7a, n = 1, L = NH2OH; 7b, n = 2, L = NH2OH) and the bridging hydrazine complexes [{Ir(mu-SC6H4 (-) (n) MenCH2)Cl(PPh3)}(2)(mu-NH2NR2)] (5a, n = 1, R = H; 5b, n = 2, R = H; 6, n = 1, R = Me), respectively. On the other hand, the reaction of 1b with MeLi resulted in reductive cleavage of the disulfide bond to give the coordinatively unsaturated diiridium() complex [Ir(mu-SC6H2Me2CH2)(SMes)(PPh3)](2) (8), which was further converted into the bis( carbonyl) complex [Ir(mu-SC6H2Me2CH2)(SMes)(PPh3)(CO)](2) (9) upon addition of CO. Treatment of 2b with AgPF6 led to the formation of the difluorophosphato-bridged complex [{Ir(mu-SC6H2Me2CH2)(PPh3)(XyNC)}(2)(mu-PF2O2)][PF6] (10). The structures of the thiairidaindan complexes 2b, 4a, 5a, 7a and 8-10 have been determined by X-ray crystallography.