We report the gas-phase UV photoelectron spectra (UPS) of some arylboronic acids for the first time. The electronic structures of 2-methyl-, 3-methyl- and 3-chloro-phenylboronic acids and 3-thienyl-boronic acid have been studied in the gas phase by HeI/HeII photoelectron spectroscopy and EOM-CCSD quantum chemical calculations. The comparison of the spectra of arylboronic acids with the spectra of toluene, chlorobenzene and thiophene shows remarkably small changes in the ionization energies of the highest occupied π-orbitals upon the attachment of the boronic acid group B(OH)₂ to the aryl core. The appearance of additional spectral bands with ionization energies of 10.5–11 eV corresponds to ionization of CB σ-bonding orbitals.

我们首次报道了某些芳基硼酸的气相紫外光电子能谱（UPS）。通过HeI / HeII光电子能谱和EOM-CCSD量子化学计算在气相中研究了2-甲基-，3-甲基-和3-氯-苯基硼酸和3-噻吩基硼酸的电子结构。芳基硼酸的光谱与甲苯，氯苯和噻吩的光谱的比较显示，在硼酸基团B（OH）₂附着到芳基核上后，最高占据π轨道的电离能变化非常小。电离能为10.5-11 eV的附加光谱带的出现对应于C Bσ键轨道的电离。