Metal Complexes of the Carbon Dioxide Dianion

只有从根本上了解了还原剂对二氧化碳分子的影响，热力学稳定、动力学惰性的底物二氧化碳才能被认为是合成和催化的碳源。本项目研究了由第3和第4族正电性和亲氧性金属衍生的二氧化碳双核配合物的合成、结构分析和机理研究。将具有不同电子和空间性质的配体与不同亲电性/亲氧性的早期过渡金属中心相结合将导致新的配位模式。一个特别的焦点是几乎未被探索的二阴离子CO22-的配位，它正式来自双去质子化的二羟基卡宾C(OH)2，对应于甲酸的互变异构体。我们认为，金属配位球内二氧化碳的化学还原可能会引发进一步的二氧化碳插入和C-C键形成反应。在合成了具有化学还原形式的二氧化碳的新的金属络合物之后，将进行机理研究。我们期待着金属介导的二氧化碳活化的新的可能性，它超越了氢化为甲酸、甲醇或甲烷，并将导致更大的构建块CN&GT；1用于合成。

The thermodynamically stable and kinetically inert substrate carbon dioxide can only be considered as a C1 source for synthesis and catalysis, if the effect of reducing agents on this molecule are fundamentally understood. This project deals with the synthesis, structural analysis and mechanistic studies of dinuclear complexes of carbon dioxide, which are derived from electropositive and oxophilic metals of groups 3 and 4. Combining ligands of varied electronic and steric properties with early transition metal centers of different electrophilicity/oxophilicity shall lead to new coordination modes. A particular focus is on the coordination of the nearly unexplored dianion CO22-, which is formally derived from doubly deprotonated dihydroxycarbene C(OH)2 and corresponds to the tautomer of formic acid. We assume that the chemical reduction of carbon dioxide within the coordination sphere of a metal may trigger further CO2 insertion and C-C bond forming reactions. After the new metal complexes with a chemically reduced form of CO2 will be synthesized, mechanistic studies will be performed. We expect new possibilities for metal mediated activation of carbon dioxide that goes beyond the hydrogenation to formic acid, methanol, or methane and shall lead to larger building blocks Cn>1 for synthesis.