Synthesis and crystal structure of [NiOs3(η-C5H5)(µ-H)2{µ-Cu(PPh3)}(CO)9]. Hydrogenation–dehydrogenation reactions of dienes and alcohols with heterogeneous catalysts derived from [NiM3(η-C5H5)(µ-H)2(µ-X)(CO)9][M = Ru, X = H; M = Os, X = Cu(PPh3)]