An isolated nitridyl radical-bridged {Rh(N.)Rh} complex

Abstract

Photochemical activation of [(PNNH)Rh(N3)] (PNNH=6-di-(tert- butyl)phosphinomethyl-2,2′-bipyridine) complex2 produced the paramagnetic (S=1/2), [(PNN)Rh-N.-Rh(PNN)] complex3 (PNN-=methylene- deprotonated PNNH), which could be crystallographically characterized. Spectroscopic investigation of 3 indicates a predominant nitridyl radical ( .N2-) character, which was confirmed computationally. Complex3 reacts selectively with CO, producing twoequivalents of [(PNN)Rh I(CO)] complex4, presumably by nitridyl radical N,N-coupling. The first isolated nitridyl radical (.N2-) complex was obtained by photochemical activation of the rhodium-azide complex [(PNNH)Rh(N3)] (1), producing N2, H2, and the paramagnetic complex2. Complex2 reacts selectively with CO to produce complex3, presumably by N,N-coupling of nitridyl radicals.