'EPSRC/NSF Workshop Collaborative Proposal' Catalytic oxidative C-H bond functionalisation with high oxidation state N-heterocyclic carbene complexes

燃烧来自化石燃料的汽油和其他碳氢化合物对环境造成了巨大的破坏，并且浪费了这些本应用于制造药物、维生素和其他提高生活质量的重要化学品的日益减少的资源。然而，这些碳氢化合物中的碳氢键不仅很强，而且强度相似，因此有选择地将一些氢交换为使分子成为有用化学物质的活性基团是很困难的。汽车催化转换器使用钯颗粒来帮助充分氧化废气中未燃烧的碳氢化合物，并保护我们免受汽油和一氧化碳中毒。催化剂使氧化更容易（它们降低了反应的能垒）。我们发现，如果你能把钯溶解在溶液中（通过用粘合剂或配体包围每个金属阳离子，使其保持溶剂化），它的选择性就会更强，一次只吸附一个碳氢化合物，从而也能吸附另一个添加的活性基团。一旦碳氢化合物附着在钯的中心，除去其中一个氢就变得容易得多，这样它就可以被一个有用的活性基团所取代。因此，溶剂化的钯化合物催化从简单的碳氢化合物形成更复杂的化合物。我们已经制造出了选择性很强的配体，它比其他配体更强地附着在钯离子上，使它们的反应性更强，但只占用足够的空间，以确保这种反应性总是对某些氢原子具有高度选择性。这将有助于制造更精细、更有选择性的药物分子。最重要的是，配体有助于在结合步骤的中间稳定钯，当它非常缺乏电子时，因此容易损坏。这也将允许添加更大范围的组。在极端情况下，在学术上最令人兴奋的钯反应中，我们计划制造稳定的分子来模拟这些反应基团添加中最脆弱的中间体，这样我们就可以详细研究它们，这样理论家就可以基于模型计算来预测钯催化的未来。因此，在未来，我们将需要更少的钯，并且能够从最简单的化石燃料和生物质衍生的有机化合物中制造出更广泛的复杂药物和药品。

Burning petrol and other hydrocarbons from fossil fuels is enormously damaging to the environment, and wasteful of these diminishing resources that should be used to make drugs, vitamins, and other important chemicals that improve the quality of life. However, the carbon-hydrogen bonds in these hydrocarbons are not only strong, but similar in strength, so selectively exchanging some of the hydrogens for the reactive groups that make the molecules into useful chemicals is difficult. Car catalytic converters use palladium particles to help fully oxidise the unburnt hydrocarbons in the exhaust, and protect us from petrol and carbon monoxide poisoning. The catalyst make the oxidation easier (they lower the energy barrier to the reaction).We have found that if you can dissolve the palladium in a solution (by surrounding each metal cation with binders, or ligands, to keep it solvated) it can be more selective, and pick up one hydrocarbon at a time, and thus also pick up another added reactive group. The moment the hydrocarbon becomes stuck to the palladium centre, it becomes much easier to remove one of its hydrogens, so it can be replaced with a useful, reactive group. Thus the solvated palladium compounds catalyse the formation of more complex compounds from simple hydrocarbons. We have made very selective ligands that stick more strongly to the palladium cations that any others, and make them even more reactive, but take up just enough space to make sure this reactivity is always highly selective for certain hydrogen atoms. This will help to make much more elaborate drug molecules, more selectively. Most importantly, the ligands help to stabilise the palladium in the middle of the combination step, when it is very electron deficient, and thus prone to damage. This will also allow a wider range of groups to be added. In the extreme, and most academically exciting palladium reactions, we plan to make stable molecules that mimic the most fragile intermediates in these reactive group additions, so we can study them in detail, and so that theoreticians can base calculations on the models to predict the future of palladium catalysis.So in the future we will need less palladium, and be able to make a wider range of complex drugs and pharmaceuticals from the simplest of fossil fuels, and biomass-derived organic compounds.