Theoretical insights into elaborating and regulating excited state dynamics for the novel 6-cyano-2-(2′-hydroxyphenyl)imidazo[1,2a]pyridine system in polar and nonpolar solvents Lei Xu Qiaoli Zhang Tianjie Zhang Dapeng Yang 10.6084/m9.figshare.9791111.v1 https://tandf.figshare.com/articles/journal_contribution/Theoretical_insights_into_elaborating_and_regulating_excited_state_dynamics_for_the_novel_6-cyano-2-_2_-hydroxyphenyl_imidazo_1_2a_pyridine_system_in_polar_and_nonpolar_solvents/9791111 <p>Given the importance of excited state relaxation in photochemical and photophysical behaviours, in this work, we mainly focus on the excited state dynamical behaviours for the novel 6-cyano-2-(2′-hydroxyphenyl)imidazo[1,2a]pyridine (6-CN-HPIP) system in different aprotic solvents. We find the ultrafast excited state intramolecular proton transfer (ESIPT) behaviour without potential energy barrier for 6-CN-HPIP in nonpolar solvents. Furthermore, we also explore the excited state intramolecular hydrogen bonding interactions and confirm the hydrogen bond O-H<math><mo>⋯</mo></math>N of 6-CN-HPIP should be strengthened based photo-excitation process. It provides the possibility of ESIPT process. And the charge redistribution resulting from photo-excitation around hydrogen bonding moieties further reveals the ESIPT tendency for 6-CN-HPIP molecule. It is worth mentioning that the increased electronic densities around proton-acceptor moiety play important roles in attracting hydrogen proton, which directly promotes ESIPT reaction. Via constructing potential energy curves, we clarify the ESIPT dynamical process for 6-CN-HPIP system and present a novel mechanism that nonpolar aprotic solvents facilitate ESIPT behaviour for 6-CN-HPIP. We hope that novel applications and developments could be promoted for 6-CH-HPIP and its derivatives through regulating and controlling ESIPT behaviours in future.</p> 2019-09-10 07:54:58 Intramolecular hydrogen bond ESIPT charge density difference charge redistribution solvent polarity