Synthesis and Study of Non-Kekule Molecules

该提案要求基金通过化学和光谱学方法检查一系列不接合的双基。分子轨道计算预测，不接合的双基将具有单线态基态。该实验室以前的工作已经发现了三态基态不接合的双基。这个理论的矛盾将用新的例子来进一步探讨，这些例子具有严格定义的结构，以便与理论计算进行比较。我们将探讨以某种方式含有环戊二烯环的非交替双基化合物。这些双基的结构和多样性之间的相互作用将被探索，其中较低的成员系统预计是单线和较高的成员系统三重。这项来自有机动力学计划的拨款支持了匹兹堡大学保罗·多德教授的继续工作。化学和光谱性质的一个新的系列反应中间体称为双自由基将被检查。双基是指两个位置都有奇数个电子的分子。例如，在碳氢化合物的双基中，两个碳原子将分别与另外三个碳原子成键，并有一个未成键的电子。两个奇数电子的自旋可以是成对的（单线态），也可以是非成对的（三重态）。双基的最低能态（单重态或三重态）将被实验确定为结构的函数。这些结果将与理论计算进行比较。

This proposal requests funds to examine a series of disjoint biradicals by chemical and spectroscopic methods. Molecular orbital calculations have predicted that disjoint biradicals will possess a singlet ground state. Previous work from this laboratory has resulted in finding a triplet ground state disjoint biradical. This contradiction of theory will be pursued further with new examples which have rigidly defined structures for comparison to theoretical calculations. Non-alternant biradicals will be explored, which contain in some fashion, cyclopentadiene rings. The interplay between structure and multiplicity of these biradicals will be explored, where lower membered systems are expected to be singlets and higher membered systems triplets. This grant from the Organic Dynamics Program supports the continuing work of Professor Paul Dowd at the University of Pittsburgh. The chemical and spectroscopic properties of a novel series of reactive intermediates known as biradicals will be examined. Biradicals are molecules where there are an odd number of electron at two sites. For example, in a hydrocarbon biradical, two carbon atoms will each be bonded to three other carbon atoms and have one unbonded electron. The two odd electrons may have spins paired (a singlet) or unpaired (a triplet). The lowest energy states (singlet or triplet) of the biradicals will be determined experimentally as a function of structure. These results will be compared to theoretical calculations.