Preparation and reactions of nitrosyl-tetrazene derivatives of Rh and Ir

Compounds of formula M(NO)(PPh₃)(N₄R₂)] (I) (M  Rh, Ir; R  SO_2^? C₆H₄CH₃) have been obtained by the interaction of M(NO)(PPh₃)₃ with p-toluene-sulphonyl azide in benzene. These new compounds are formulated as tetrazene derivatives on the basis of chemical and spectroscopic data. They react with ligands, L, (e.g. CO, PPh₃ to give pentacoordinated species of formula M(NO)(PPh₃(L)(N₄R₂)].The tetrazene derivatives yield the new nitrosyl compounds, M(NO)(PPh₃)Cl₂ (II) on treatment with HCl, the nitrogen-containing residue being converted into RN₃ and RNH₂ species. The compounds (II) are coordinatively unsaturated, and react with ligands L in the same manner as compounds (I), giving new derivatives of formula M(NO)(PPh₃)(L)Cl₂.IR and NMR spectra of the new compounds are reported and discussed. The presence in solution of a structure in which the chelate tetrazene ring has opened {e.g. M(NO)(PPh₃)(NR)(N₃R)]} is suggested by NMR studies.