Theoretical study on electronic structures and luminescent properties of phenol-pyridyl boron complexes

Electronic properties, such as HOMO and LUMO energies, band gaps and the ionization potentials (IP) of five boron complexes containing mixed phenol-pyridine donor set, were studied by the density functional theory with Becke-Lee-Young-Parr composite exchange correlation functional (B3LYP). The absorption spectra of these complexes were also investigated by time dependent density functional theory (TDDFT) with 6-31G∗ basis set. The calculated results indicated that the HOMO and LUMO of the complexes are both destabilized by electron-donating substituents (CH3 and NH2). Seen from IPs, they all exhibit good hole-transporting ability, and their correlations with HOMO energies is linear. The TDDFT calculations showed that different substituents on the phenol-pyridyl unit lead to nominal change on the absorptions of these boron complexes. The calculations on the structural, electronic and optical properties of the compounds are in good agreement with the experimental data.