Photoinduced intramolecular charge transfer in methyl ester of N,N′-Dimethylaminonaphthyl-(acrylic)-acid: Spectroscopic measurement and quantum chemical calculations

The excited state intramolecular charge transfer process of a synthesized donor–acceptor naphthalene chromophoric system methyl ester of N,N′-Dimethylaminonaphthyl-(acrylic)-acid (MDMANA) has been investigated spectroscopically in combination with quantum chemical calculation. Apart from the local emission the molecule shows a solvent polarity dependent low energy emission from the charge transfer excited state. In polar protic solvents ground state hydrogen bonded clusters of MDMANA are formed which also shows low energy emission. Structural calculation and potential energy surfaces along both the donor and acceptor twist coordinates by considering twisted intramolecular charge transfer (TICT) model at density functional theory (DFT) level predict that a stabilized twisting geometry is responsible for charge transfer emission. The solvent polarity effect on the emission spectra has been explored using time-dependent density functional theory-polarizable continum model (TDDFT-PCM) which correlates well with the experimental spectral data.