Investigation of charge transfer and structural distortions during photo-inducted excitation of cuprous bis-2,9-dimethyl-1,10-phenanthroline complex by density functional theory

This work reported the investigation of the structural distortions and charge-transfer processes that occurred in the complex of cuprous(I) bis-2,9-dimethyl-1,10-phenanthroline (Cu(dmp)2+) upon oxidation to copper(II), Cu(dmp)22+, through a excited state of Cu(dmp)2+ by density functional theory. The intramolecular electronic transfer from central metal-to-ligand (MLCT) upon the irradiation of light energy is confirmed. Due to this MLCT excitation, the structure of the excited state of Cu(dmp)2+ is distorted and reorganized to adapt with the change of charge in central metal. As a result, the excited state of Cu(dmp)2+ is formed, which has the similar electronic and structural properties with Cu(dmp)22+. The bulky substituents in 2- and 9-positions of the phenanthroline ligands can restrain the structural distort and decrease nonradiative decay rate. Thus, the electronic and steric effects of the ligands in the cuprous photo-sensitive complexes have important consequences in the behavior of their excited state.