Xiao Hongmei, Ma Lishuang, Fang Weihai, Chen Xuebo
Key Laboratory of Theoretical and Computational Photochemistry of Ministry of Education, Department of Chemistry, Beijing Normal University , Xin-wai-da-jie No. 19, Beijing, 100875, Peoplés Republic of China.
J Phys Chem A. 2017 Jul 6;121(26):4939-4947. doi: 10.1021/acs.jpca.7b04817. Epub 2017 Jun 21.
Utilization of photoinitiated isomerization reaction has recently emerged as a very promising platform to modulate the basicity of compounds; however, theoretical insight into its regulatory mechanism remains largely unknown and needs to be addressed. For the first time, an unexpected trans-cis photoisomerization via the N═N out of plane (NOOP) motion triggered by an in-plane inversion of N-N═N moiety was computationally demonstrated to regulate the pOH jump of water-solvated triazabutadiene by using the multiconfigurational perturbation theory together with the calculation of rate constants of protonation-deprotonation reactions. Kinetic analyses show that the dramatic pOH change can be attributed to the reinforced intramolecular hydrogen bonding resulting from water cluster reorientation and the enhanced coupling between the rotated π orbital and N lone pair of triazabutadiene in the remarkable trans-cis photoisomerization.
光引发异构化反应的应用最近已成为一个非常有前景的调节化合物碱性的平台；然而，对其调控机制的理论认识在很大程度上仍然未知，需要加以解决。首次通过计算证明，由N-N═N部分的面内反转引发的通过N═N面外（NOOP）运动的意外反-顺式光异构化，利用多组态微扰理论以及质子化-去质子化反应速率常数的计算，调节水合三氮杂丁二烯的pOH跃变。动力学分析表明，显著的pOH变化可归因于水簇重新定向导致的分子内氢键增强，以及在显著的反-顺式光异构化中旋转的π轨道与三氮杂丁二烯的N孤对之间增强的耦合。
