PROTONATION OF DIPHOSPHINE AND PHOSPHITE DERIVATIVES OF DODECACARBONYLTRIRUTHENIUM

Protonation of the clusters [Ru3(CO)10(mu-diphos)] where diphos = Ph2P(CH2)nPPh2 [dppm (n = 1), dppe (n = 2), dppp (n = 3) or dppb (n = 4)] with CF3CO2H gave the monohydrido cations [Ru3(mu-H)(CO)10(mu-diphos)]+, initially characterised by NMR methods. The compounds [RU3(mu-H)(CO)10(mu-diphos)][PF6] were isolated for dppp and dppb, but deprotonation occurred more readily for dppm and dppe and in these cases the salts could not be isolated. The hydride and the diphos ligands span the same edge of the metal triangle in the dppp and dppb cations [Ru3(mu-H)(CO)10(mu-diphos)]+ but different edges in the dppm species. The two interconverting isomers are observed in solution when diphos = dppe correspond to these different forms. Protonation of [Ru3(CO)10(P(OMe)3}2] with CF3CO2H gives [Ru3(mu-H)(CO)10{P(OMe)3}2]+ as two isomers in solution, the major with equivalent and the minor with non-equivalent phosphite ligands.