Quantum Chemical Study of Structures, Electronic Spectrum, and Nonlinear Optical Properties of Gold−Pentacene Complexes

Abstract

Four isomers formed by a gold atom attached to a pentacene molecule were investigated by density functional theory due to their potential applications in molecular electronics. The aim of our study is to shed light on the bonding nature and interaction between gold and carbon, to estimate the influence of gold atoms on the electronic spectrum of the pentacene, and to predict second-order nonlinear optical (NLO) properties. The results show that the gold and carbon atom of systems 1 and 2 can form a covalent bond, which has σ single-bond character. However, there are strong donor−acceptor interactions between gold and carbon of systems 3 and 4. The influence of the number of benzene rings on the bonding nature or interactions is also discussed. Adding a gold atom to the pentacene obviously changes the transition nature of pentacene and results in an increase in possible transition, especially for systems 3 and 4. These systems possess moderate molecular second-order polarizabilities compared with the organ...