Experimentally Validated Model for the Prediction of the HOMO and LUMO Energy Levels of Boronsubphthalocyanines

摘要

We report the rapid screening of phenoxyboron-subphthalocyanine (PhO-BsubPc) derivatives for sensitivity of their HOMO and LUMO energy levels (E_H and E_L) to substitution with electron-donating and electron-withdrawing functional groups using semiempirical methods. Subsequently, we have synthesized a selection of seven PhO-BsubPc derivatives, further modeled the seven derivatives using DFT methods, and measured or determined their respective E_H and E_L. We have used a combination of ultraviolet photoelectron spectroscopy (UPS), cyclic voltammetry (CV), and ultraviolet-visible (UV-vis) spectroscopy to correlate the computational predictions with experimental data. From these experimental and computational results, we have shown that E_H and E_L of PhO-BsubPcs are more sensitive to peripheral substitutions than to substitution on the axialphenoxylate. The frontier molecular orbitals, calculated using DFT methods, were found to be exclusively located on the boronsubphthalocyanine ligand among the seven PhO-BsubPc derivatives. A mathematical model correlating computational results with experimental data was determined which can be subsequently used to rapidly predict how structural factors influence the E_H and E_L to direct synthetic and engineering efforts.