CYCLOOLIGOMERISATION OF CO AT U(III) CENTRES AND RELATED STUDIES

一氧化碳是一种非常重要的工业原料，广泛用于费托工艺氢气还原大规模生产碳氢化合物和醇。直接将CO分子偶联在一起形成更大的(CO)n单元的概念是一个吸引人的概念；然而，尽管Fischer-Tropsch反应有很长的历史，一氧化碳已被证明在温和的条件下对这种选择性同源反应具有显著的抵抗性。环状、芳香、氧碳阴离子CnON2-(n=3-6)原则上可以通过这种路线获得，这可能为直接从CO合成复杂有机分子提供新的策略。这一建议建立在我们最近发现的一种铀(III)有机金属络合物的基础上，该络合物将在非常温和的条件下还原循环CO，形成位于两个铀中心之间的三角双阴离子C3O2-。在拟议的研究中，我们将研究该反应的机理，生成一个具有催化作用的体系，并在与铀结合的三角洲单元上进行反应，形成更大的有机环(例如，还原型酸--一种重要的抗氧化剂)。我们还将对铀(III)络合物进行修饰，以允许组装更大的(CO)n单元，并研究该系统对其他重要小分子的激活作用，例如二氧化碳。

Carbon monoxide is a very important industrial feedstock, and is used extensively for the large scale production of hydrocarbons and alcohols via reduction with hydrogen in the Fischer-Tropsch process. The concept of directly coupling CO molecules together directly to form larger units of (CO)n is an appealing one; however, despite the long history of the Fischer-Tropsch reaction, carbon monoxide has proven remarkably resistant to such selective homologation under mild conditions. The cyclic, aromatic, oxocarbon anions CnOn2- (n= 3-6), in principle, are accessible by such a route, which may provide new strategies for the synthesis of complex organic molecules directly from CO. This proposal builds on our very recent discovery of a uranium(III) organometallic complex which will reductively cyclise CO under very mild conditions to from the deltate dianion, C3O3 2-, held between two uranium centres. In the proposed research, we will study the mechanism of this reaction, generate a system which is catalytic, and carry out reactions on the uranium-bound deltate unit to form larger organic rings (e.g. reductic acid- an important antioxidant). We will also modify the uranium(III) complex to allow the assembly of larger units of (CO)n, and investigate the activation of other important small molecules, e.g. CO2, by this system.