| 论文简介 |
Unidirectional rotation represents a very important functional feature in photochemistry, such as for the design of light-driven molecular rotary motors. Great attention has recently been paid to the unidirectional preference of the torsional motion of azobenzene and other molecules. Azoheteroarenes offer functional advantages over their more conventional azobenzene counterparts by the introduction of heteroaromatic rings. In this paper, the Z-E photoisomerzation dynamics of two azoheteroarenes, 1,2-bis(1-methyl-1H-imidazol-2-yl)diazene and 1,2-bis(1H-imidazol-2-yl)diazene, are investigated with trajectory surface-hopping molecular dynamics at the semiempirical OM2/MRCI level. Starting from the S1 excited state of the M-helical Z-isomer of both azoheteroarenes, more than 99% of the trajectories decay to their ground states through the M-helical conical intersections by twisting about the central N=N double bond. This chiral path preference can be well understood by the energy profiles generated by the linear interpolation between the Franck-Condon geometry of the M-helical Z-isomer and the relevant S1/S0 conical intersections. The Z-E photoisomerzation mechanisms of these two azoheteroarenes display a higher preference for unidirectional rotary dynamics under a chiral path than their counterpart azobenzene. |
(创新港)
