Crescent-shaped rhodium(I) complexes with bis(o-carboxymethylphenyl)triazenide

摘要

Reaction of [{Rh(mu-Cl)(CO)(2)}(2)] with the triazene ArNNNHAr (Ar = o-CO2MeC6H4) produced the mononuclear complex [RhCl(ArNNNHAr)(CO)(2)] (1). Complex 1 reacted with KOH in methanol to give the dinuclear compound [{Rh(mu-ArNNNAr)(CO)(2)}(2)] (2), which showed a "mu-(1kappaN(1),2kappaN(3))-ArNNNAr" coordination mode for both bridging ligands. The dinuclear complex [{Rh(mu-ArNNNAr)(CO)(2)}(2)] (2) easily undergoes redistribution reactions in which the eight-membered "Rh-2(NNN)(2)" core is broken. Thus, reaction of 2 with the anionic complex (NHEt3)[RhCl2(CO)(2)] gave the single-bridged complex (NHEt3)[Rh-2(mu-ArNNNAr)Cl-2(CO)(4)] (4), while the trinuclear complexes [Rh-3(mu-ArNNNAr)(mu-Cl)(mu-CO)Cl(CO)(4)] (5) and [Rh-3(mu-ArNNNAr)(2)(mu-Cl)(mu-CO)(CO)(3)] (6) were isolated by addition of the neutral compound [{Rh(mu-Cl)(CO)(2)}(2)] to 2, depending on the molar ratio employed. The formation of 5 and 6 involved the loss of carbonyl groups and the coordination of the oxygen atoms of the CO2Me groups. The structures of 4, 5, and 6 have been determined by X-ray diffraction methods, which show the ability of bis(o-carboxymethylphenyl)-triazenide to act as bi-, tri-, and tetra-dentate ligand-spanning dinuclear moieties in trinuclear complexes.