Preparation and characterization of chemically bonded argon-boroxol ring cation complexes.

The cation complexes [ArBO], [ArBO], [ArBO] and [ArBO] were prepared a laser vaporization supersonic ion source in the gas phase. Their vibrational spectra were measured mass-selected infrared photodissociation spectroscopy. Spectroscopy combined with quantum chemical calculations revealed that the [ArBO], [ArBO] and [ArBO] cation complexes have planar structures each involving an aromatic boroxol ring and an argon-boron covalent bond. In contrast, the [ArBO] cation is characterized to be a weakly bound complex with a BO chain structure.