Spectroscopic study of excited state intramolecular charge transfer in ethyl ester of N, N′-Dimethylaminonaphthyl-(acrylic)-acid

Abstract

In this work, we have studied the twisted intramolecular charge transfer process in ethyl ester of N, N′-Dimethylaminonaphthyl-(acrylic)-acid (EDMANA) using absorption and emission spectroscopy. Single conformer of EDMANA present in the ground state gives rise to local and charge transfer emission in different solvents. Solvatochromic effect on the Stokes shifted emission band clearly indicates the charge transfer character of the emitting singlet excited state. Considering twisted intramolecular charge transfer model, the ground and excited state properties of EDMANA have been evaluated along the donor and acceptor twisting coordinates separately using density functional theory (DFT) and time dependent density functional theory (TDDFT), respectively, with B3LYP functional and 6-31G basis set. The effect of solvent on the spectral properties has been explored theoretically at the same level with time dependent density functional theory-polarized continuum model (TDDFT-PCM) and the theoretical results support the solvent polarity dependent Stokes shifted emission of EDMANA molecule.