Multi N-Heterocyclic Carbene Complexes of Ruthenium for the Coordination and Reactivity of Small Molecules

小分子如O2、H2和N2在化学转化中的利用依赖于它们能够首先与反应性过渡金属络合物配位。我们最近报道（J。2009，131，9618; Chem.Eur.Chem.Soc.2009，131，9618; J. 2009，15，10912），其显示出结合这些气体的选择性作为NHC取代基的函数。我们现在希望在这些初步观察的基础上，看看这种Ru多NHC“支架”是否可以用于将结合的O2，H2和N2分子纳入催化反应中（氧化、氢化等），并且，基于或附加的初步结果，我们是否可以诱导更多的外来分子类型，如白色磷（P4）和氨硼烷（R2 HNBH 3）将努力制备含有异常配位的NHC的新Ru（NHC）4片段，提供反应性杂原子氢化物产物和前体，以长期寻求用于分子间C-H活化的裸16 e RuL 4物质。我们将建立在更多的初步结果与Ru（NHC）3片段，努力使催化H-X加成烯烃。重要的是要确定我们发表的工作和初步数据所暗示的这些多NHC络合物的丰富化学是否可以从Ru扩展到其他过渡金属，无论是在同一组（特别是Fe）还是周围的组（Mo，W，Re）。

The utilisation of small molecules such as O2, H2 and N2 in chemical transformations relies on them being able to first coordinate to reactive transition metal complexes. We have recently reported (J. Am. Chem. Soc. 2009, 131, 9618; Chem. Eur. J. 2009, 15, 10912) a new ruthenium complex containing four N-heterocyclic carbene (NHC) ligands that shows selectivity in binding these gases as a function of the NHC substituents. We now wish to build upon these initial observations to see whether this Ru multi-NHC 'scaffold' can be used to incorporate the bound O2, H2 and N2 molecules into catalytic reactions (oxidation, hydrogenation etc) and, on the basis or additional preliminary results, whether we can induce more exotic types of molecules such as white phosphorus (P4) and ammonia boranes (R2HNBH3) to take part in both novel stoichiometric and catalytic transformations.Efforts will be directed at preparing new Ru(NHC)4 fragments that contain abnormally coordinated NHCs, afford reactive heteroatom hydride products and precursors to long sought after naked 16e RuL4 species for intermolecular C-H activation. We will build upon more preliminary results with a Ru(NHC)3 fragment in an effort to bring about catalytic H-X addition to alkenes. It is important to establish whether the rich chemistry of these multi-NHC complexes hinted at by our published work and preliminary data can be extended on from Ru to other transition metals, both in the same group (specifically Fe) and surrounding groups (Mo, W, Re).