Turro Nicholas J
Chemistry Department, Columbia University, New York, NY 10027, USA.
Chem Commun (Camb). 2002 Oct 21(20):2279-92. doi: 10.1039/b205552j.
The reactions of carbon centered radical pairs often involve diffusion controlled combination and/or disproportionation reactions which are non-selective. A triplet geminate pair of radicals is produced by the photolysis of suitable ketones. The reactions of such geminate pairs can be controlled though the application of supramolecular concepts which emphasize non-covalent interaction to "steer" the geminate pair toward a selected pathway. In addition, "superdupermolecular" concepts, which emphasize the control of radical pair reactions through the orientation of electron spins, can be employed to further control the course of geminate pair reactions. Examples of control of a range of the selectivity of geminate radical combinations, which form strong covalent bonds, through supramolecular and superdupermolecular effects will be presented for the photolysis of ketones adsorbed in the supercages of zeolites.
以碳为中心的自由基对的反应通常涉及扩散控制的结合和/或歧化反应，这些反应是非选择性的。通过合适酮的光解可产生三重态双自由基对。通过应用强调非共价相互作用以“引导”双自由基对走向选定途径的超分子概念，可以控制此类双自由基对的反应。此外，强调通过电子自旋取向控制自由基对反应的“超级超分子”概念，可用于进一步控制双自由基对反应的进程。对于吸附在沸石超笼中的酮的光解，将给出通过超分子和超级超分子效应控制一系列形成强共价键的双自由基组合选择性的实例。
