...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Structural Control of Nonadiabatic Bond Formation: The Photochemical Formation and Stability of Substituted 4a,4b-Dihydrotriphenylenes
【24h】

Structural Control of Nonadiabatic Bond Formation: The Photochemical Formation and Stability of Substituted 4a,4b-Dihydrotriphenylenes

机译：非绝热键形成的结构控制：取代的4a，4b-二氢三亚苯基的光化学形成和稳定性

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Nonadrabatic photocyclization Makes bonds and is the first step in the photoinduced cyclodehydrogenation of ortho-arenes to yield polycyclic aromatic hydrocarbons. How molecular structure alters potential-energy landscapes, excited state dynamics, and stabilities of reactants and intermediates underlies the feasibility of desirable photochemistry. In order to gain insight into these structure dynamics relationships, we have used ferntosecond transient absorption spectroscopy (TAS), to examine photoinduced dynamics of 1,2,3-triphenylbenzene (TPB) and ortho-gnaterphenyl- (OQT-P), phenyl-subsituted analogues of ortho-terphenyl (OTP.). Dynamics of TPB and OTP are quite sin-lilac TPB exhibits fast (7.4 ps) excited state decay with concomitant formation and vibrational relaxation of 9-phenyl-dihydrotriphenylene (9-phenyl DHT). In contrast, photoexcited OQTP exhibits multistate kinetics leading to, formation. of 1-pheilyl,DHT. Excited-state calculations reveal the existence of two distinct minima on the OCUP S, surface and together with photophysical data, support a mechanism involving both direct cyclization by way of an asymmetric structure and indirect cyclization, by way of a Symmetric quinoid like minimum. Temperature-dependent nanosecond TAS was utilized to assess the relative stabilities of intermediates, substantiating the observed trend in photochemical reactivity OTP OQTP > TPB. In total, this work demonstrates how specific Structural variations alter the course of the excited state dynamics and photoproduct stability-that underlies desired photochemistry.
机译：非阿拉伯光环化形成键，是邻芳烃光诱导环脱氢以产生多环芳烃的第一步。分子结构如何改变势能态，激发态动力学以及反应物和中间体的稳定性，奠定了理想的光化学可行性的基础。为了深入了解这些结构动力学关系，我们使用了飞秒瞬态吸收光谱法（TAS）来研究1,2,3-三苯苯（TPB）和邻萘基苯基-（OQT-P），苯基-取代了邻三苯基（OTP。）。 TPB和OTP的动力学特性是完全正丁香的TPB表现出快速的（7.4 ps）激发态衰减，伴随着9-苯基-二氢三亚苯基（9-苯基DHT）的形成和振动弛豫。相反，光激发的OQTP表现出导致形成的多态动力学。 1-苯甲酰基，DHT。激发态计算揭示了OCUP S表面上存在两个截然不同的极小值，并与光物理数据一起，支持了一种机制，该机制涉及通过非对称结构进行直接环化和通过类似最小对称对称醌的间接环化。温度依赖性纳秒TAS用于评估中间体的相对稳定性，从而证实了光化学反应OTP OQTP> TPB的观察趋势。总的来说，这项工作证明了特定的结构变化如何改变激发态动力学和光产物稳定性的过程，而这正是所需光化学的基础。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号