Reaction of nido-1,2-(Cp∗RuH)2B3H7 with ethynylferrocene to yield new metallacarboranes

Addition of ethynylferrocene to nido-1,2-(Cp∗RuH)2B3H7 (1) at ambient temperature leads to nido-1,2-(Cp∗Ru)2(1,5-μ-C{Fc}Me)B3H7 (2, 3) and closo-4-Fc-1,2-(Cp∗RuH)2-4,6-C2B2H3 (4). Compounds 2 and 3 represent a pair of geometric isomers, nido-species in which the regiochemistry of the alkyne reduction conforms to the Markovnikoff rule. Compound 4 is an octahedral structure in which the inserted alkyne is on an open face of the closo cluster.