Transition Metal Sigma Bond Complexes

华盛顿大学化学系的Michael Heinekey得到了无机，生物无机和有机化学计划的支持，用于探索金属-二氢和金属-烷烃相互作用。具体而言，该项目将针对：（1）使用NMR光谱和H/D/T标记的细长二氢复合物的结构和动力学;（2）使用磁性不等价测量耦合的对称顺式二氢化合物中的交换耦合;（3）通过CO的光挤出或通过使用甲硅烷基阳离子试剂的氯化物提取产生的σ键（如C-H和Si-H键）与亲电金属中心的配位;（3）低势垒动力学，包括使用甚低温NMR光谱和同位素取代测量顺式H2 /H体系的动力学同位素效应;（3）通过使用中性和/或阳离子Ir（I）的烃C-H键的分子间活化和可能的官能化，吡唑基环中的强C-H键的分子内活化络合物均相催化研究的一个重要的当前目标是理解金属结合和底物如二氢的活化，烷烃和硅烷只存在与金属中心相互作用的σ键，有关这些物质的信息以前已有只是通过间接测量，但在这项研究中，他们将直接观察。此外，教育和培训未来的科学家和新的核磁共振方法的发展是这项工作的主要影响。

Michael Heinekey, Department of Chemistry, University of Washington is supported by the Inorganic, Bioinorganic and Organometallic Chemistry Program for explorations of metal-dihydrogen and metal-alkane interactions. Specifically, the project will target: (1) The structure and dynamics of elongated dihydrogen complexes using NMR spectroscopy and H/D/T labels; (2) Exchange coupling in symmetrical cis dihydrides using magnetic inequivalence to measure couplings; (3) Coordination of sigma bonds such as C-H and Si-H bonds to electrophilic metal centers generated by photoextrusion of CO or by chloride abstraction using silyl cation reagents; (3) Low barrier dynamics, including the measurement of kinetic isotope effects, of cis H2 /H systems using very low temperature NMR spectroscopy and isotope substitution; (3) Intramolecular activation of the strong C-H bonds in pyrazolyl rings by intermolecular activation and possible functionalization of hydrocarbon C-H bonds using neutral and/or cationic Ir(I) complexesAn important current goal of research in homogeneous catalysis is to understand the metal binding and activation of substrates such as dihydrogen, alkanes and silanes which present only sigma bonds for interaction with the metal center Information about these species has previously been available only through indirect measures, but in this study they will be directly observed. In addition, the education and training of future scientists and the development of new NMR methods are major impacts of this work.