Experimental and theoretical studies on the electronic structure of trisubstituted boroxine

The electronic structures of trisubstituted boroxine Me3B3O3 and (MeO)3B3O3 were investigated by using photoelectron spectroscopy. Ab initio and DFT calculations have been carried out for the assignments of the PE spectra. The experimental first ionization energies of Me3B3O3 and (MeO)3B3O3 are 11.42 and 10.78 eV. These correspond to the ionization of the electron from the boron–carbon σ bonding orbital and the lone pair π orbital on the oxygen atom out of the boroxine ring, respectively.