How the electronic and steric properties of the ligand can determine the stability of the asymmetric dinuclear carbonyl-phosphite Rh(0) complex (CO)2(P(O-o-tBuPh)3)Rh-Rh(P(O-o-tBuPh)3)(CO)3

Theoretical studies have shown that the low basicity of the phosphite ligand P(O-o-tBuPh)3 in the Rh(0) complex (CO)2(P(O-o-tBuPh)3)Rh-Rh(P(O-o-tBuPh)3)(CO)3 favours the non-bridged structure over the bridged one, but is not responsible for the absence of the expected sixth carbonyl in the structure. The steric effects of the bulky ligand play an important role in the unusual stability of the asymmetric complex.