Synthesis and properties of iron-group hydrido-cyano complexes trans-[MH(CN)(L)2], M = Fe, Ru or Os, L = diphosphine, and their hydrogen, trifluoroboron and triphenylboron isocyanide derivatives of the type trans-[MH(CNH)(L)2]O3SCF3, trans-[MH(CNBX3)(L)2], X = F or Ph, and trans-[M(H2)(CNBF3)(dppp)2