Methimazolyl based diptych bicyclo-[3.3.0]-ruthenaboratranes.

The reactions of [RuCl(R)(CO)(PPh3)2] (R = CH[double bond, length as m-dash]CHPh, Ph) with Na[H2B(mt)2] (mt = N-methyl-2-mercaptoimidazolyl) transiently provide [Ru(R)(CO)(PPh3){κ3-H,S,S'-H2B(mt)2}] which each evolve to the ruthenaboratrane [Ru(CO)(PPh3)2{κ3-B,S,S'-BH(mt)2}](Ru→B)8. The phosphine ligands may be selectively replaced to provide the complexes [Ru(CO)(L)(PPh3){κ3-B,S,S'-BH(mt)2}] (L = CO, PMe2Ph) and [Ru(CO)L2{κ3-B,S,S'-BH(mt)2}] (L = PMe2Ph, P(OMe)3, L2 = Z-Ph2PCH[double bond, length as m-dash]CHPPh2) with, in each case, retention of the ruthenium-boron dative bond.