Research On Construction And Performance Of Copper-based Metal-organic Compounds

Metal-organic complexes with advantages of adjustable structures, diverse functions, easy synthesis and high yield, have been the first choice for the enzyme simulation objects. With increasing of the global energy demands and dwindling of the fossil fuel supplies, solar power has become an alternative and sustainable power source for human. Therefore, as for solar power utilization, the critical issue is to seek an expedite way to transform solar power into chemical energy.Hydrogenase exists in microbial body in nature, which can efficiently catalyse the hydrogen evolution under mild conditions. Using metal organic complexes to simulate the structures and function of hydrogenase is a useful way to realize the photocatalytic hydrogen evolution in the sun. This thesis chose low cost transition metal copper as the metal nodes, constructs a metal-organic ring structure with open cavity, and studied its application in photocatalytic hydrogen production system.Aniline and salicylaldehyde are chosen to synthesize the N, O-bidentate schiff-base ligand and then by combining with copper(II) to build a single core metal-organic complexe Cu-L1. The X-ray single crystal diffraction technology is used to characterize its structure. And its stability in solution was confirmed by ESI-MS. Under the 500 W xenon lamp illumination, using copper metal-organic complexe as artificial enzyme catalysts, fluorescein as photosensitizer, triethylamine as the electronic sacrifice agent, photocatalytic hydrogen evolution in a homogeneous system was successfully realized. Under the optimal condition, the TON reached to 140.As the mononuclear copper metal-organic complex was easily inactivated and low efficiency, two and three nuclear copper metal-organic ring complexes Cu-L2 and Cu-L3 are constructed, respectively, with the same coordination configuration as Cu-L1. X-ray single crystal diffraction indicated that Cu-L3 possesed proper cavity and window size compared with Cu-L2, which can inclose fluorescein molecule inside its big ring cavity. Under the optimal condition, the TON was up to 1200. Under the host-guest system, the photosensitizer encapsulated in the ring cavity enables photo-induced electron transfer from the excited state of the photosensitizer to the copper-based catalytic sites via a powerful pseudo-intramolecular pathway. This way not only improves the efficiency of the electron transfer, but features an enzymatic dynamics behavior.