Theoretical Study of Rhodium(I) Carbene Complexes: The Structural Versatility of Phosphino- Compared with Aminocarbenes
Résumé
Density functional calculations are reported for complexes of general formula [(carbene)RhClL2] featuring model phosphino- and aminocarbenes. Both the cis and trans isomers of the rhodium(I) η 1-complexes (1-9) were investigated, and the influence of the rhodium co-ligands (L= ethylene, phosphine, or carbon monoxide) was evaluated. In the case of phosphinocarbenes and carbon monoxide as a ligand, a somewhat unusual coordination mode was observed, in which a significant intramolecular Cl→Ccarbene interaction is present. The propensity of phosphino- and aminocarbenes to behave as four electron donors was also investigated both structurally and energetically on the related η2-complexes 10-18. These results as a whole emphasize the structural versatility of phosphino- compared with aminocarbene complexes.