School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK. Department of Computer Science, Merchant Venturers Building, Woodland Road, Bristol BS8 1UB, UK. Photon Ultrafast Laser Science and Engineering (PULSE) Institute and Department of Chemistry, Stanford University, Stanford, CA 94305, USA. SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.
Science. 2015 Jan 30;347(6221):530-3. doi: 10.1126/science.aaa0103.
Solvent-solute interactions influence the mechanisms of chemical reactions in solution, but the response of the solvent is often slower than the reactive event. Here, we report that exothermic reactions of fluorine (F) atoms in d3-acetonitrile and d2-dichloromethane involve efficient energy flow to vibrational motion of the deuterium fluoride (DF) product that competes with dissipation of the energy to the solvent bath, despite strong solvent coupling. Transient infrared absorption spectroscopy and molecular dynamics simulations show that after DF forms its first hydrogen bond on a subpicosecond time scale, DF vibrational relaxation and further solvent restructuring occur over more than 10 picoseconds. Characteristic dynamics of gas-phase F-atom reactions with hydrogen-containing molecules persist in polar organic solvents, and the spectral evolution of the DF products serves as a probe of solvent reorganization induced by a chemical reaction.
溶剂-溶质相互作用影响溶液中化学反应的机制，但溶剂的响应通常比反应事件慢。在这里，我们报告说，在 d3-乙腈和 d2-二氯甲烷中，氟 (F) 原子的放热反应涉及到将能量有效地传递到氟化氘 (DF) 产物的振动运动中，这与将能量耗散到溶剂浴中竞争，尽管溶剂耦合很强。瞬态红外吸收光谱和分子动力学模拟表明，在 DF 形成其第一个氢键的亚皮秒时间尺度之后，DF 的振动弛豫和进一步的溶剂重构发生在超过 10 皮秒的时间内。气相 F-原子与含氢分子反应的特征动力学在极性有机溶剂中持续存在，DF 产物的光谱演化可作为化学反应引起的溶剂重组的探针。
