Terminal imido rhodium complexes

Compounds of the late transition metals with M≡X multiple bonds (X=CR2, NR, O) represent a synthetic challenge, partly overcome by preparative chemists, but with noticeable gaps in the second- and third-row elements. For example, there are no isolated examples of terminal imido rhodium complexes known to date. Described herein is the isolation, characterization, and some preliminary reactivity studies of the first rhodium complexes [Rh(PhBP3)(NR)] (PhBP3=PhB{CH2PPh2}3) with a multiple and terminal RhN bond. These imido compounds result from reactions of organic azides with the corresponding rhodium(I) complex having a labile ligand, and display a pseudo-tetrahedral core geometry with an almost linear Rh-N-C arrangement [177.5(2)°] and a short Rh-N bond [1.780(2) Å]. We also show that the Rh-N bond undergoes protonation at the nitrogen atom or addition of H2, and also engages in nitrene-group transfer and cycloaddition reactions.The generous financial support from MICINN/FEDER (Project CTQ2011-22516) and Gobierno de Aragón/FSE (GA/FSE, Inorganic Molecular Architecture Group, E70), are gratefully acknowledged. A.M.G. thanks the Gobierno de Aragón for a fellowship.Peer Reviewe