Electronic structures and solvent effects of unsymmetrical neo-confused porphyrin: DFT and TDDFT-IEFPCM investigations

Unsymmetrical porphyrin derivatives and metal-coordinated porphyrin have received great attention in potential application for their intriguing photo-physical and photo-chemical properties. Density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations were applied to simulate the molecular and electronic structures with the electronic absorption spectra of the unsymmetrical neo-confused porphyrin (NeoCP) derivatives. Molecular structure and fragment charge distribution results revealed that the carbon-nitrogen-swap structure lead to the redistribution of charges and the differentiation of inner hydrogen in the Neo-confused Porphyrin ring. Introducing the unsymmetrical strategy onto the porphyrin skeleton effectively varied the energy levels of molecular orbitals, resulting in significant multi-band photon absorption and Soret band splitting for the porphyrin derivatives. Ni coordinated NeoCP (NiNeoCP) showed broader visible light absorption capacity and better light absorption performance due to the contribution of Ni atom. The blue-shifted Q bands illuminate that the light absorption performance of NeoCP and NiNeoCP varies in different polarity solvents based on the integral equation formalism polarizable continuum model (IEF-PCM) results. These theoretical researches would be conducive to the molecular design of novel multi-band photon absorption porphyrin derivatives. (C) 2016 Published by Elsevier B.V.