Selective Photocatalytic Hydroxylation of Inert Hydrocarbons Such as Methane Using Air as the Oxidant

使用空气作为氧化剂对甲烷等惰性烃进行选择性光催化羟基化

• 批准号: 131338096
• 负责人: Professor Dr. Siegfried Schindler
• 金额: --
• 依托单位: Institut für Anorganische Chemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2009
• 资助国家: 德国
• 起止时间: 2008-12-31 至 2012-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/131338096?language=en
• 关键词: Selective; Photocatalytic; Hydroxylation; Inert; Hydrocarbons

The low-temperature conversion of hydrocarbons into more reactive intermediates, e.g. alcohols, is a great challenge for catalysis. In contrast nature has already proved that reactions of this type can be performed under ambient conditions using enzymes such as methane monooxygenases that are based on iron or copper ions in the active site. Studies on selective oxidations, using low molecular weight iron or copper complexes as model compounds for these enzymes thus far mainly have been performed as thermal processes. In contrast, in our collaborative project, we now want to incorporate photochemical key-steps for the following reasons: a) Excited state molecules are much more powerful oxidants (as well as reductants) than the corresponding ground state species. Thus, a peroxo metal complex for example, that will not oxidize a certain hydrocarbon under ambient conditions, might well be able to perform this reaction upon irradiation. b) It could be possible to photochemically generate new oxygen complexes as reactive species that are otherwise very difficult to obtain through a normal chemical reaction. c) The electron distribution and spin characteristics of metal-oxo fragments and related reactive intermediates may be influenced and controlled by light absorption. Therefore, we plan to study reactions such as the reaction of metal ozonides to form a mononuclear metal-oxo complex releasing dioxygen if activated by light. Such complexes are regarded as extremely powerful oxidants and could be used for selective oxidations in situ. Furthermore, it is well known that several peroxo complexes are light sensitive. Again, investigations will be performed to find out, if such a peroxide can be directly transformed into a metal oxo complex by photoinduced processes. Methane and other hydrocarbons will be reacted with different oxygen complexes , e.g. dinuclear copper peroxo species, dioxygen adducts or metal oxo compounds under exposure to mono- and polychromatic light.

将碳氢化合物低温转化为更具反应性的中间体，例如醇，对催化来说是一个巨大的挑战。相反，自然界已经证明这种类型的反应可以在环境条件下使用诸如基于活性位点中的铁或铜离子的甲烷单加氧酶的酶进行。迄今为止，使用低分子量铁或铜络合物作为这些酶的模型化合物对选择性氧化的研究主要是通过热过程进行的。相比之下，在我们的合作项目中，我们现在希望纳入光化学关键步骤，原因如下：a）激发态分子是比相应基态物质更强大的氧化剂（以及还原剂）。因此，例如过氧金属络合物，在环境条件下不会氧化某些碳氢化合物，很可能能够在辐射下进行该反应。 b) 可以通过光化学方式产生新的氧络合物作为活性物质，否则很难通过正常的化学反应获得这些活性物质。 c) 金属氧片段和相关反应中间体的电子分布和自旋特性可能受到光吸收的影响和控制。因此，我们计划研究诸如金属臭氧化物形成单核金属氧配合物的反应，如果被光激活则释放双氧。这种配合物被认为是极其强大的氧化剂，可用于原位选择性氧化。此外，众所周知，几种过氧配合物是光敏感的。再次，将进行研究以确定这种过氧化物是否可以通过光诱导过程直接转化为金属氧配合物。甲烷和其他碳氢化合物将与不同的氧络合物发生反应，例如：暴露于单色光和多色光下的双核铜过氧物种、双氧加合物或金属氧化合物。