REDOX-CATALYZED ISOMERIZATION OF [RH2(MU-CO)(BIPY)-(PH2PCH2CH2PPH2)(MU-N1,N3-RNNNR)2]2+TO[RH2(MU-CO)(BIPY)-(PH2PCH2CH2PPH2)(MU-N1,3,N3-RNNNR)(MU-N1,N3-RNNNR)]2+(BIPY = 2,2'-BIPYRIDYL, R = PARA-TOLYL) - AN UNPRECEDENTED BONDING MODE FOR THE BRIDGING TRIAZENIDE LIGAND

Treatment of [Rh2(mu-CO)(bipy)(dppe)(mu-N1,N3-RNNNR)2]2+ 1(2+) [bipy = 2,2'-bipyridyl, dppe = 1,2-bis(diphenylphosphino)ethane, R = p-tolyl] with a catalytic amount of [NBun4][BH4] gave [Rh2(mu-CO)-(bipy)(dppe)(mu-N1,3,N3-RNNNR)(mu-N1,N3-RNNNR)]2+ 3(2+) X-ray studies on which show one 'normal' bridging triazenide ligand and one in which one of the terminal N atoms binds one Rh atom while the second bonds to both metal atoms; the triazenide ligands of 3(2+) are cis-bound to one metal centre and trans- bound to the second.