Warren Jeffrey J, Menzeleev Artur R, Kretchmer Joshua S, Miller Thomas F, Gray Harry B, Mayer James M
University of Washington, Department of Chemistry, Box 351700 Seattle, WA 91195-1700 ; California Institute of Technology, Department of Chemistry, 1200 E. California Blvd. Pasadena, CA 91125.
J Phys Chem Lett. 2013 Feb 7;4(3):519-523. doi: 10.1021/jz400029w. Epub 2013 Jan 14.
Concerted proton-electron transfer (CPET) reactions in iron carboxy-tetraphenylporphyrin complexes have been investigated using both experimental and theoretical methods. Synthetic heme models abstract H and e from the hydroxylamine TEMPOH or an ascorbate derivative, and the kinetics of the TEMPOH reaction indicate concerted transfer of H and e. Phenylene linker domains vary the electron donor/acceptor separation by approximately 4 Å. The rate data and extensive molecular simulations show that the electronic coupling decay constant (β) depends on conformational flexibility and solvation associated with the linker domain. Our best estimate of β is 0.23 ± 0.07 Å, a value that is near the low end of the range (0.2-0.5 Å) established for electron transfer reactions involving related linkers. This is the first analysis of β for a CPET reaction.
已使用实验和理论方法对铁羧基四苯基卟啉配合物中的协同质子-电子转移（CPET）反应进行了研究。合成血红素模型从羟胺TEMPOH或抗坏血酸衍生物中提取H和e，并且TEMPOH反应的动力学表明H和e的协同转移。亚苯基连接域使电子供体/受体间距变化约4 Å。速率数据和广泛的分子模拟表明，电子耦合衰减常数（β）取决于与连接域相关的构象灵活性和溶剂化作用。我们对β的最佳估计值为0.23±0.07 Å，该值接近涉及相关连接体的电子转移反应所确定范围（0.2 - 0.5 Å）的低端。这是对CPET反应中β的首次分析。
