Transition Metal-Nitrogen Multiple Bonds

David Wigley博士，亚利桑那大学化学系，由无机化学、生物无机化学和金属有机化学计划支持，研究过渡金属-氮多键的化学。长期以来，有机亚胺配体一直被用作辅助基团，以实现不同程度的空间保护，并支持处于最高氧化态的金属。然而，高活性的金属酰亚胺部分并不为人所知。这项研究的总体目标是更好地了解过渡金属-氮多键，并开发利用金属-亚胺基团的新方法。为了扩大它们的反应范围，将利用D2金属-亚硝基和-偶氮络合物开发新的金属催化的烯烃叠氮化反应，并研究涉及亚胺中间体的化学计量和催化过程。这些氮杂环化反应中可能的金属环中间体将通过独立的路线制备，并作为机械探针进行检查。将合成新的Ru的亚胺络合物，并探索其作为硝烯[NR]转移试剂的用途。最后，金属-亚胺配合物将被开发为具有合成有机化学价值的电环重排试剂，在一定条件下可以生成高活性的金属-亚胺基团，这些基团由过渡金属键合到带有单一附加取代基的氮上组成。这些金属-亚胺络合物激活了甲烷中的C-H键，在工业上重要的烯烃氢胺化和烯烃氮化反应中发挥着核心作用，并已被用于模拟加氢脱氮、丙烯氨氧化和丁腈还原催化步骤。尽管活性金属-亚胺类化合物很重要，但它们的数量仍然很少，而且它们的性质也没有很好地系统化。在本研究中，我们将合成一些新的亚胺类化合物，开发新的活化金属亚胺基团的方法，扩大它们的反应范围。

Dr. David Wigley, Chemistry Department, University of Arizona, is supported by the Inorganic, Bioinorganic, and Organometallic Chemistry Program for studies of the chemistry of transition metal-nitrogen multiple bonds. Organoimido ligands have long been used as ancillary groups to variable degrees of steric protection and to support metals in their highest oxidation states. However, highly reactive metal-imide moieties are not well known. The overall objective of this research is to gain a better understanding of transition metal-nitrogen multiple bonding and to develop new methods for utilizing metal-imido moieties. To extend the range of their reactions new metal-mediated alkene aziridination reactions will be developed using d2 metal-nitroso and -azo complexe with both stoichiometric and catalytic processes that involve imido intermediates being investigated. The probable metallacyclic intermediates in these aziridinations will be prepared by independent routes and examined as mechanistic probes. New imido complexes of ruthenium will be prepared and their utility as nitrene [NR] transfer reagents will be explored. Finally, metal-imido complexes will be developed as reagents for electrocyclic rearrangements of value to synthetic organic chemistry.Highly reactive metal-imide groups, which are composed of a transition metal bonded to a nitrogen that bears a single additional substituent, can be generated under certain conditions. These metal-imido complexes activate C-H bonds in methane; play a central role in the industrially important hydroamination of olefins and olefin aziridination; and have been used to model steps in hydrodenitrogenation, propylene ammoxidation, and nitrile reduction catalysis. Despite the importance of reactive metal-imido complexes, their numbers remain small and their properties are not well systematized. In this research a number of new imido complexes will be prepared, new methods for activating metal imido groups will be developed, and the range of their reactions will be extended.