Solvent-Initiated Photochemistry of Transition Metal Complexes

圣克拉拉大学化学系的帕特里克霍格德博士是 由无机，生物无机和有机物计划支持， 化学部进行自由基链反应的研究， 通过光的吸收引发的溶液， 溶剂后 具体来说，他将确定最初的氧化是否 氯仿溶剂引发的反应中的试剂是过氧自由基或 氢过氧化物。基于金属的量子产率增加的反应 随着辐射波长的降低将使用锇进行探索， 钼和钯的双核和三核物种 溶剂.钌联吡啶反应将探讨条件下， 在试图发现光可逆的过程中氧不是限制性的， 温度敏感系统潜在应用实例 这些现象包括周期性改变组成的系统 在辐射下，“智能”眼镜，在超过一个小时的辐射下变暗， 给定的温度和光催化系统来破坏 水中的卤代烃。 光能的吸收通常用于引发化学反应。 反应.当这些反应在氯化溶剂中发生时， 反应物本身是否吸收了 能量，或者溶剂分子是否先吸收能量，然后 转移到反应物中。 这是一个重要的机械问题 由于可由透明的玻璃形成的潜在应用， 了解这些过程和相应的能力， 操纵他们。 霍格德医生会检查一系列的金属复合物 具有不同还原电位的基质，并寻找新的 溶剂引发的光反应。 他还将继续努力， 氯代烃在水介质中降解的研究， 对温度高度敏感的反应。 这些类型的 光反应可以有很高的量子产率， 用于降解环境有害的柠檬酸氯化物 芳香烃.

Dr. Patrick Hoggard, Department of Chemistry, Santa Clara University, is supported by the Inorganic, Bioinorganic, and Organometallic Program of the Chemistry Division to perform studies of radical chain reactions in solution which are initiated through the absorption of light by the solvent. Specifically, he will determine whether the initial oxidizing agent in chloroform solvent-initiated reactions is a peroxy radical or a hydroperoxide. Reactions in which the metal-based quantum yield increases with decreasing irradiation wavelength will be explored using osmium, molybdenum and palladium di- and tri-nuclear species in chlorinated solvents. Ruthenium bipyridine reactions will be probed under conditions where oxygen is not limiting in an attempt to discover photoreversible, temperature-hypersensitive systems. Examples of potential applications of these phenomena include systems that periodically change composition under irradiation, `smart` glasses that darken under irradiation above a given temperature, and photocatalytic systems for the destruction of halogenated hydrocarbons in water. The absorption of light energy is commonly used to initiate chemical reactions. When these reactions take place in chlorinated solvents, there is some ambiguity as to whether the reactants themselves absorb the energy, or whether the solvent molecules absorb the energy first and then transfer it to the reactants. This is an important mechanistic question because of the potential applications which can result from a clear understanding of these processes and the corresponding ability to manipulate them. Dr. Hoggard will examine a series of metal complex substrates with differing reduction potentials and search for new solvent-initiated photoreactions. He will also pursue photocatalysis studies of chlorohydrocarbon degradation in aqueous media as well as reactions which are hypersensitive to temperature. These types of photoreactions can have high quantum yields, and may have implications for the degradation of environmentally recalcitrant chlorinated hydrocarbons.