四齿中性Pt(N^C^C^N)光催化剂设计合成及其催化羧基化反应研究

针对目前可见光催化剂中环金属Pt配合物光催化剂化学稳定性差、催化效率不佳的问题，本项目利用二价Pt配合物中心金属离子dsp2杂化轨道为平面四边形构型，易于和四齿配体进行环金属化反应的特点，设计并合成系列四齿中性环金属Pt(N^C^C^N)配合物光催化剂。通过对其结构和分子中3LC、MLCT、MC能级的调节来优化最低激发三线态(T1)的性质，进而调节整个催化剂分子的化学稳定性和催化效率，结合理论计算研究配合物结构对光催化剂性能的影响规律，以解决Pt配合物光催化剂稳定性和催化效率的问题。同时将发展的四齿中性环金属Pt(N^C^C^N)配合物光催化剂用于可见光促进的胺、醛酮、醚、烯烃以及芳烃类化合物的选择性C-H键活化-羧基化反应中，通过对反应机理进行深入研究，揭示影响反应的基本规律和决定性因素，为新反应的发展提供指导。

Contraposing some problems presently existing in the photocatalysts utilized in the visible light photoredox catalysis, such as poor chemical stabilities and efficiencies of the cyclometalated platinum complex photocatalysts, the objectives of this project will aim at utilizing dsp2 hybrid orbital of the divalent Pt cation which enable cyclometallation with the tetradentate ligands easily to develop a series of neutral tetradentate cyclometalated Pt(N^C^C^N) photocatalysts with square planar configurations. The chemical stabilities and efficiencies of the photocatalysts will be improved through adjusting the molecular structures and the 3LC, MLCT and MC energy levels to change the T1 properties of the photocatalysts. Moreover, the relationship between the chemical structures and catalytic efficiencies of the Pt(N^C^C^N) complexes will also be investigated to solve the stabilities and efficiencies problems of the photocatalysts. Furthermore, the photocatalysts will be used in the selective C-H bond activation-carboxylation reactions of CO2 with the amines, aldehydes, ketones, ethers, alkenes and arenes. The reaction mechanism will also be in-depth understood to disclose the basic laws and critical reasons of the reactions, which can also derect the development of new reactions.