Direct Observational Studies of Carbenes

这项有机和大分子化学的资助为罗格斯大学Robert Moss博士的研究提供了支持。羰基化合物是有机化学中一类重要的反应中间体，本研究的重点是对其进行直接观察研究。它们之所以重要，是因为它们具有不寻常的反应性，这是因为碳烯缺乏电子，可以以多种可达电子状态存在。碳烯和其他高活性中间体的基础研究将通过直接光谱观察和绝对动力学方法进行。利用重氮嘧啶卤化物交换反应制备二甲氧基甲苯和氟甲氧基甲苯的新型重氮嘧啶前驱体。对于二甲氧基卡宾，光谱、绝对动力学、活化参数和反应性研究将确定这种代表性亲核卡宾的行为。将对氟甲氧基甲苯进行平行研究。测定了碳/烯烃加成反应的激活自由能，并对其进行了焓/熵分配。其他要研究的碳化合物包括甲氧基甲基碳化合物、氟甲基碳化合物和二甲氨基甲氧基碳化合物。还将测量苯基卤代烃添加到受阻烯烃的活化参数，其中已经观察到不寻常的行为。最后，研究了从二氮嘧啶和羰基化合物中生成羰基离子的几种方法。

This grant in Organic and Macromolecular Chemistry provides support for the research of Dr. Robert Moss, Rutgers University. The work is focused on the direct observational studies of carbenes, which are a class of important reaction intermediates in organic chemistry. They are important because of their unusual reactivity which arises because carbenes are electron deficient and can exist in more than one accessible electronic state. Fundamental studies of carbenes and other highly reactive intermediates will be carried out by direct spectroscopic observation and absolute kinetic methods. The diazirine halide exchange reaction will be used to prepare novel diazirine precursors for dimethoxycarbene and fluoromethoxycarbene. For dimethoxycarbene, spectroscopic, absolute kinetic, activation parameter, and reactivity studies will define the behavior of this representative nucleophilic carbene. Parallel studies will be made with fluoromethoxycarbene. The free energies of activation of the carbene/alkene addition reactions will be determined and analyzed for enthalpy/entropy partition. Other carbenes to studied include methoxymethylcarbene, fluoromethylcarbene, and dimethylaminomethoxycarbene. Activation parameters will also be measured for additions of phenylhalocarbenes to hindered alkenes, where unusual behavior has already been observed. Finally, several methods of generating carbonium ion from diazirines and carbenes will be studied.