Department of Chemistry, POSTECH, Pohang, 37673, Republic of Korea.
Department of Chemistry, The Catholic University of Korea, Bucheon, 14662, Republic of Korea.
Phys Chem Chem Phys. 2023 Jul 5;25(26):17230-17237. doi: 10.1039/d3cp01169k.
1,2-Dihydro-1,2-azaborine is an isoelectronic analog of benzene with a B-N substitution, and its unique photoisomerization behavior, which is distinct from that of benzene, has drawn significant attention. To understand the detailed mechanism of azaborine photochemistry considering the dynamical effect and gain a comprehensive understanding of photochemical reactions, we investigated the photoisomerization dynamics of azaborine using nonadiabatic molecular dynamics simulations with Tully's surface hopping algorithm. Herein, the structural and energetic analyses of the trajectories revealed three different paths: direct relaxation (path 1), relaxation a prefulvene-like intermediate (path 2), and formation of the Dewar isomer as a photoproduct (path 3). Our results confirmed that the photoisomerization of azaborine follows the energetically favored pathway predicted by the previous minimum energy path (MEP) calculations, exclusively forming the Dewar isomer, which is consistent with the experimental observations. Additionally, despite the low quantum yield found in our simulations, the high-level excitation energy calculations support the complete conversion observed in the experiments.
1,2-二氢-1,2-氮杂硼烷是苯的等电子体类似物，具有 B-N 取代基，其独特的光异构化行为与苯不同，引起了广泛关注。为了考虑动力学效应，深入了解氮杂硼烷光化学的详细机制，从而全面理解光化学反应，我们使用含 Tully 表面跳跃算法的非绝热分子动力学模拟研究了氮杂硼烷的光异构化动力学。在此，轨迹的结构和能量分析揭示了三条不同的路径：直接弛豫（路径 1）、弛豫至类富烯中间体（路径 2）和作为光产物形成 Dewar 异构体（路径 3）。我们的结果证实，氮杂硼烷的光异构化遵循先前最低能量路径（MEP）计算预测的能量有利途径，仅形成 Dewar 异构体，这与实验观察结果一致。此外，尽管我们的模拟中量子产率较低，但高水平激发能计算支持实验中观察到的完全转化。
