Study On The Synthesis And Photocatalytic Activity Of Conjugated Porous Polymer Based On Click Chemistry

Over the past decade,visible light induced chemical transformations have received considerable attention due to their green and sustainable features.Some commonly used photocatalytic systems like ruthenium or iridium complexes,and organic molecular dyes,have been successfully designed and developed.Apart from these homogeneous photocatalysts,graphitic carbon nitrides（g-C₃N₄）,a class of metal-free solid materials,have also found application as heterogeneous photocatalysts.Conjugated porous polymers（CPPs）,a sub-set of porous organic polymers（POPs）,are another emerging class of metal-free photocatalysts and extensively investigated in recent years.Owing to their porous structures,high chemical and thermal stabilities,extendedπ-electron systems,and tunable band gaps,CPPs have served as an efficient and stable platform for heterogeneous photocatalytic chemical transformations.Aromatic azo compounds are an important class of raw materials and widely used as dyes and pigments,free radical initiators,photoresponsive functional devices,food additives,therapeutic agents,and indicators.Due to the high value of aromatic azo compounds,great effort has been made for the synthesis of aromatic azo compounds.However,classic methods have many disadvantages,such as long reaction time,high catalyst loading,toxic reagent,large inorganic waste,harsh reaction conditions,poor selectivity,and low catalyst reusability,limit their practical utility.Here,we report a facile approach to prepare 1,2,3-triazole contained CPPs（Ta-Ths）through click reaction of azide and terminal alkynes,and employ the click-based CPPs for the first time as photocatalysts.By changing the structure of alkyne monomer,Ta-Ths with distinct optoelectronic properties are obtained to effectively catalyze the visible light-driven oxidative dehydrogenation of hydrazo aromatics.Moreover,the Ta-Ths show much higher catalytic activity as compared with previous homogeneous photocatalysts.The Ta-Th-2 that possesses better charge transfer efficiency and lower charge recombination rate was found to have more catalytic activity than the others.In addition,this protocol was demonstrated on a gram scale without any erosion of yield.Furthermore,the polymer photocatalyst has shown reliable recyclability with no significant loss in its catalytic activity.