Infrared Photodisssociation Spectroscopy of Boron Carbonyl Cation Complexes

The boron carbonyl cation complexes B(CO)₃⁺, B(CO)₄⁺ and B₂(CO)₄⁺ are studied by infrared photodissociation spectroscopy and theoretical calculations. The B(CO)₄⁺ ions are characterized to be very weakly bound complexes involving a B(CO)₃⁺ core ion, which is predicted to have a planar DD_3h structure with the central boron retaining the most favorable 8-electron configuration. The B₂(CO)₄⁺ cation is determined to have a planar D_2h structure involving a B-B one and half bond. The analysis of the B-CO interactions with the EDA-NOCV method indicates that the OC→B σ donation is stronger than the B→CO π back donation in both ions.