Abstract:
The electron-induced 1, 2-dicyano-1, 2-dithienylethene photoisomerization process were studied by CASSCF and MS-CASPT2. The results showed that the S1→S0 decay of neutral 1, 2-dicyano-1, 2-dithienylethene needs to readjust the geometry to reach the S1/S0conical intersections, which resulted from carbon-pyramidalization mode and is therefore away from the CC torsional coordinates. As results, it slows down the speed of CC rotation and hinders its directionality;while in cationic and anionic isomerization processes, the D1 and D0 PESs intersect along the rotary path, therefore, the nonadiabatic D1→D0 decay is barrierless. Consequently, the speed and directionality of CC rotation is maintained. This study proved that the electron can effectively tune the photoisomerization, and shed light on the design of light-driven molecular rotary motors.
