Phosphorus-Boron Multiple Bonding in the π Radical HBP

Chemistry. 2023 Mar 22;29(17):e202203704. doi: 10.1002/chem.202203704. Epub 2023 Feb 16.

Abstract

The HBP radical was generated via the reaction of laser ablated boron atom with PH3 in a solid neon matrix, which is identified via IR spectroscopy with isotopic substitutions and quantum chemical calculations. The results show that HBP has a 2 Π electronic ground state with a short B-P bond. Bonding analysis indicates that besides an electron-sharing σ bond, there are two degenerate π bonding orbitals that are occupied by three electrons, resulting in a bond order of two and half between P and B. This is in sharp contrast to the bonding properties of the isovalent HNB, which was characterized to be a N≡B triply bonded σ radical with the unpaired electron locating on the B atom.

Keywords: boron; matrix isolation; multiple bonding; phosphorus; vibrational spectroscopy.