Synthesis And Properties Of Novel Molecules Photocatalytic Photosensitizer

Solar energy is clean and renewable,so it is important to convert solar energy into high-density chemical energy photocatalytic system.Among them,photosensitizer,as the main body of light absorption and the medium of electron transfer,plays an important role in the process of light energy conversion.Traditional photosensitizers(such as[Ru(bpy)₃]²⁺)are limited by the short lifetime of the excited state and weak visible light absorption.In order to solve these problems,this paper focuses on the preparation of new metal photosensitizers and the control photophysical properties to achieve efficient photolysis of hydrogen(H₂)and photocatalytic reduction of carbon dioxide(CO₂),at the same time,the development of high activity non precious metal photosensitizers and the construction of cheap photocatalytic system for the preparation of high value-added organic chemicals.The specific research contents are as follows:In this paper,the photocatalytic properties of Ru(II)complexes about different excited states were systematically studied.Three kinds of photosensitizers(Ru-2,Ru-3 and Ru-4)were introduced to achieve effective regulation.The results show that the overall photocatalytic activity of ³IL complexes(Ru-4 and Ru-3)is three times higher than that of ³MLCT complexes(Ru-1 and Ru-2),which is mainly attributed to the superior photostability and long lifetime of excited state of ³IL photosensitizer(Ru-4,?=120?s).Further development of copper photosensitizer to replace precious metal photosensitizer for photocatalysis.In this paper,through-bond energy transfer(TBET)strategy was applied to construct Cu(I)-based photosensitizers with strong visible light absorption and long lifetime of excited states,which were used to efficiently drive energy transfer and electron transfer photocatalytic reactions.The first copper based photosensitizers(Cu-2 and Cu-3)with strong visible light absorption was prepared.The molar extinction coefficient of Cu-3 at 518 nm is as high as 162260M^-1cm^-1,which is 62 times higher than that of traditional copper photosensitizer(Cu-1).The sensitization performance of Cu-3 is significantly better than that of traditional copper photosensitizer(Cu-1)and precious metal photosensitizer([Ru(bpy)₃]²⁺and[Ir(ppy)₃]⁺).Finally,we developed a triplet photosensitizer heavy atom free photosensitizers(HAPFs)for photocatalytic study.In this paper,a series of photosensitizers B-1 to B-8based on BODIPY unit were constructed and applied to photocatalytic CO₂ reduction.B-8 showed excellent photocatalytic activity,producing CO as high as 1311.4?mol,selectivity close to 100%,which provided a new way to design efficient molecular photosensitizer.