Synthesis of hydridotriosmium complexes containing isomeric μ-carboxamido, {μ(O, C)-OC(NHR)}, μ-formamido, {μ(O, N)-OC(H)N(R)}, and μ-iminyl, {μ(C, N)-C(OR′)=NR}, groups. Crystal and molecular structure of Os3{μ-H,μ-C(OR′)=NCH3}(CO)10, R′ = C (=O)NHCH3