Complexes of four-membered group 13 metal(I) N-heterocyclic carbene analogues with metal carbonyl fragments

The four-membered gallium(I) and indium(I) heterocycles, [:M(Giso)] (M = Ga or In; Giso = {[N(Ar)]2CN(C6H11)2}–, Ar = C6H3iPr2-2,6), were treated with a series of transition metal carbonyl complexes. These reactions afforded the complexes [Fe(CO)4{Ga(Giso)}], [(CO)3Co{μ-Ga(Giso)}2Co(CO)3], [Ru(CO)2(PPh3)2{M(Giso)}] and [CpMo(CO)2{[(Giso)Ga]2OH}], which were crystallographically and/or spectroscopically characterized. The results of the study show that the two heterocycles can act as σ-donor ligands, but they are not as nucleophilic as, for example, group 13 diyls, :MR (M = Ga or In; R = alkyl, aryl, etc.). In addition, the degree of π-back-bonding in their metal carbonyl complexes does not appear to be significant