Study Of C（sp²）-H/N-H Oxidative Amination And Semiconductor Biohybrid Photocatalytic CO₂ Reduction

Solar energy is a green,pollution-free and rich natural content renewable energy.Therefore,the transformation and utilization of solar energy has become a hot topic in chemical research in recent years.Among them,photocatalysis is an important and hot research field,which aims to make efficient utilize of solar energy to realize material conversion,and solve the environmental and energy problems faced by today’s society.The research of photocatalysis involves the following aspects:the design and synthesis of photocatalysts;development of photocatalytic system;development and utilization of photocatalytic reaction;and the in-depth study of catalytic mechanism.The introduction of this paper summarizes the research progress in two different fields of photocatalysis,and the researches are based on these aspects.In particulars,there are two part:the synthesis of small molecule photocatalyst and application of photocatalytic in chemical biology.The main research contents listing as follows:（1）We redesigned the oxidative coupling reaction between phenothiazine derivatives and aniline derivatives.The reaction conditions were simple and efficient so that it performed well in flow-chemistry conditions,proved its potential for industrialization.Triphenylamines were also compatible with this reaction,what’s more,the product can be used as a photosensitizer,which shows a relatively good activity in the dehalcogenation reaction.（2）Site-selective modification of phenylalanine was sucessfully achieved via photocatalytic radical C-H amination reaction.And it was further applied in the insulin modification.What’s more,this protocol also provides a new idea for C-H amination reaction by using cheap and accessible pyran salt as a photosensitizer.（3）A semi-artificial photosynthetic system was sucessfully constructed in which CO₂reduction occured via proton-coupled electron transfer process.Palladium nanocrystal was loaded on hollow porous titanium dioxide nanospheres,and purple membrane was then coated on its surface.Bacterial rhodopsin in purple membrane can drive the proton pump to increase the proton concentration in vesicles;on the other hand,the Schottky barrier between titanium dioxide and palladium promotes the enrichment of electrons to palladium nanoparticles;then,the proton-coupled electron transfer enabled the high efficiency of carbon dioxide being reduced to methane.What’s more,it also provides a new idea for semi artificial photosynthesis of whole cells and artificial cell technology.