Phosphorus‐Boron Multiple Bonding in the π Radical HBP

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 2Π 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.

BP double bonds relieved from steric encumbrance: matrix-isolation infrared spectroscopy of the phosphaborene F2B–PBF and the triradical BPF3

“…F 2 B–PF is predicted to have a 2 A′′ ground state with C s symmetry, in contrast to its hydrogen analogue H 2 B–PH that shows a non-planar structure. 13 F 2 B–PF is computed to be the most stable isomer of its formula, 111.3 kcal mol −1 below the doublet B PF 3 compound. As shown in Fig.…”

“…Instead the radical species HBP and H 2 BPH were observed with formal B–P bond orders of 2.5 and 1.5, respectively (Scheme 1c). 13 Furthermore, only homosubstituted (R = R′) small phosphaborenes have been considered in the above mentioned theoretical investigations, with the single exception of the ClBPF species. 3,12 On the contrary, it has recently been proposed that dissimilar ligands with opposite electronic properties (π-donor and π-acceptor abilities for R and R′, respectively) can be used to stabilize the RBPR′ moiety.…”