Exploration Of Aldehyde-based Organic Visible Light Catalyst

The catalyst is an indispensable component in most chemistry reactions.However conventional catalysts generally contain precious metals,which are expensive and result in high reaction costs.The cheap metal catalysts and organic small molecule catalysts are cheaper than the precious metal catalysts,but their catalytic effects are generally inferior to precious metal catalysts.Our group has been committed to using cheap metal catalysts and organic small molecular catalysts to replace those expensive catalysts to catalyze the reaction,and to achieve the same catalytic efficiency as possible.Based on such research demand and research background,we have used several cheap and readily available catalysts to complete the main work of this paper.This paper is mainly composed of three parts.(1)We found that the optical properties of salicylaldehyde changed dramatically after deprotonation,and a strong absorption peak appeared at 417 nm in the visible light absorption region.Taking advantage of the feature,we tried to use it to catalysis visible light catalyzed organic photoreaction,and completed the reaction of NHPI ester and biphenyl isonitrile to form phenanthridine derivative.After that,we further studied the reaction mechanism by fluorescence quenching and other experiments.The catalytic activity of deprotonated salicylaldehyde in visible-light photo catalysis has also been demonstrated by its application in the decarboxylative alkylations of substituted thiophenol derivatives or disulfane derivatives and aerobic oxidation N-alkylpyridinium salts.(2)Because of the large conjugate framework,uniform pore size,and high specific surface area,the two-dimensional covalent organic framework is speculated to be a heterogeneous visible light catalyst.We use aromatic aldehydes and amino compounds as building blocksto synthesize covalent organic frameworks and characterize their optical physical properties,we used COF to complete multiple visible light catalyzed organic photo reactions,which verifying our conjecture.In the recovery experiment,the catalytic activity of the covalent organic framework can still be well maintained.(3)The study found that Lewis acid can catalyze the dehydration of aldoxime to nitrile.The reaction is simple and efficient.We further screened the catalyst and found that stannous chloride can complete the reaction in the presence of base and water.The use of stannous chloride to complete the one-pot two-step reaction from aldehyde to hydrazine omit the trouble of intermediate treatment.