山本 典史, Pacifichem (2021)
Theoretical insights into the mechanisms of aggregation-induced emission of a cyanostilbene derivative
Pacifichem 2021, オンライン, ポスター発表
An approach to quantitatively analyze the factors contributing to the activation of aggregation-induced emission (AIE) of a molecule is proposed using molecular simulations.
A cyanostilbene derivative, 1-cyano-1,2-bis-(4′-methylbiphenyl)ethylene (CN-MBE), has two isomers, E and Z forms. The E-form of CN-MBE exhibits AIE, and is non-emissive in dilute solutions but becomes highly emissive in aggregated states. The Z-form is non-emissive, even in the solid state, that is, the E-form of CN-MBE is AIE-active, while its Z-form is AIE-inactive.
In this study, the free energy profiles of the AIE processes of the E and Z forms of CN-MBE are investigated using the free energy perturbation method at the quantum mechanics/molecular mechanics (QM/MM) level.
The free energy profiles reveal significant differences in the extent to which steric hindrance from surrounding molecules restricts the intramolecular motions of the E and Z forms in the aggregated states. This study determines the contributing factors that cause the AIE activity of the molecule by identifying characteristic differences in the free energy profiles of the AIE processes of the AIE-active E-form of CN-MBE and the inactive Z-form.
The approach used in this study can be applied to the rational design of highly efficient AIE luminogens utilizing computer modeling