Biradical-like Reactive Intermediates

在化学系有机动力学项目的支持下，科罗拉多大学博尔德分校的Josef Michl教授和他的合作者将在他们的传统兴趣领域开展两个项目，即光物理学和光化学，并在第三个项目上开展工作，该项目涉及碳硼烷化学领域的活性中间体及其可分离类似物。第一个项目是与他们目前的努力，以了解低聚硅烷，原型σ共轭系统的电子结构，并与他们的垂直激发态的弛豫与激发能本地化，并试图发现和分配他们的三重激发态。激发单重态的几何弛豫将使用时间分辨拉曼光谱检查。三重态的检测将低聚硅烷光谱学与第二个项目联系起来，该项目利用了当前资助期内在提高电子能量损失光谱仪灵敏度方面取得的成就。预计这将允许在低聚硅烷中检测自旋禁戒跃迁，但也可以在碳氟化合物中，在各种基质隔离的物种中，以及其他样品中。第三个项目涉及从阴离子二十面体碳硼烷HCB 11 Me 11（-）衍生的化合物的化学。它仍然是相对较新的这个研究小组，并建立在发现一种新型的活性中间体，这是在目前的赠款期。它们是同分异构的碳鎓和硼鎓叶立德HCB 11 Me 11，在初步实验中表现出不寻常的反应性，现在将详细研究。全烷基化和全氟烷基化碳硼烷阴离子也将用作空间上庞大的保护基团，以稳定含有主族元素的缺电子原子的结构，用于结构和光谱研究以及化学反应性的检查。CB 11 Fx（CF 3）12-x型全氟阴离子将用于稳定高活性阳离子。有机和大分子化学计划支持科罗拉多大学博尔德分校的Josef Michl教授的研究，该研究将影响反应中间体化学领域。对这一领域的贡献将通过在合成有机，无机，物理和理论化学领域的科学期刊上发表文章进行交流。这项工作预计将有助于教育和培训的本科生，研究生和博士后学生在一系列跨学科的实验和理论方法，从键合理论，电子物理学，光谱学，光化学，物理有机和无机以及制备化学。

With the support of the Organic Dynamics Program in the Chemistry Division, Professor Josef Michl of the University of Colorado-Boulder and his collaborators will work on two projects in the area of their traditional interests, photophysics and photochemistry and on a third project that involves reactive intermediates and their isolable analogs in the field of carborane chemistry. The first project is related to their current effort to understand the electronic structure of oligosilanes, prototypical sigma-conjugated systems, and deals with the relaxation of their vertical excited states that are associated with excitation energy localization, and with an attempt to discover and assign their triplet excited states. The geometrical relaxation of the excited singlets will be examined using time-resolved Raman spectroscopy. The detection of the triplet states connects oligosilane spectroscopy to the second project, which takes advantage of the accomplishments attained in the current grant period with respect to improving the sensitivity of an electron energy loss spectrometer. This is expected to permit the detection of spin-forbidden transitions in oligosilanes, but also in fluorocarbons, in various matrix-isolated species, and additional samples. The third project deals with the chemistry of compounds derived from the anionic icosahedral carborane, HCB11Me11(-). It is still relatively new to this research group and builds on the discovery of a new type of reactive intermediates that was made in the current grant period. These are the isomeric carbonium and boronium ylides HCB11Me11, which show unusual reactivity in preliminary experiments and will now be examined in detail. Peralkylated and perfluoroalkylated carborane anions will also be used as sterically bulky protecting groups to stabilize structures containing electron-deficient atoms of main group elements for structural and spectroscopic studies and well as an examination of chemical reactivity. Perfluorinated anions of the type CB11Fx(CF3)12-x will be used for the stabilization of highly reactive cations. The Organic and Macromolecular Chemistry Program supports the research of Professor Josef Michl of the University of Colorado-Boulder that will impact the field of reactive intermediate chemistry. Contributions to this field will be communicated through publications in scientific journals in the areas of synthetic organic, inorganic, physical, and theoretical chemistry. The work is expected to contribute to the education and training of undergraduate, graduate, and postdoctoral students in a range of interdisciplinary experimental and theoretical methods spanning an area from bonding theory, photophysics, spectroscopy, and photochemistry to physical organic and inorganic as well as preparative chemistry.