Applications Of Perylenequinonoid Photosensitizers On Visible Light Photocatalysis

As a more environmentally friendly organic synthesis technology than traditional synthesis methods,visible light catalysis has become a green and mild way to achieve unique chemical reactivity with the most sustainable energy provided by sunlight.Compared with inorganic metal photocatalysts,organic dye photocatalysts have remarkable absorption under light and their photo-redox properties are more controllable,which can be fine-tuned by design and synthesis.Organic Dye photocatalysts are cheap,easy to operate,and do not contain metal ions in the molecules,low toxicity,making the reaction in the post-processing is more convenient,and more environmentally friendly.In this paper,a series of photocatalysis reactions have been carried out and the application of Cercosporin,a natural lipophilic perylenequinonoid photosensitizer,has been expanded,it lays the foundation for the follow-up research.The specific work is as follows:The first part is the use of cercosporin obtained by fermentation as a catalyst to realize the synthesis of nitrogen-containing heterocyclic compounds under visible light irradiation,and extensive substrate expansion.We studied the substrate tolerance range of [4+1] cyclization reaction,including electron-withdrawing groups,electron-donating groups,and furan and pyridine analogs.The results show that except pyridine,other groups get products in 65% to 90% yield,for the [4+2] cyclodimerization reaction,the electron-donating,electron-withdrawing and neutral group products almost all have a yield of more than 70%.Afterwards,we gave possible reaction mechanisms for the synthesis of two types of nitrogen-containing heterocyclic compounds through free radical trapping experiments and electron spin resonance detection experiments.Through this part of our work,we established the link between microbial fermentation and organic photocatalysis,and constructed nitrogen-containing heterocycles in a sustainable and environmentally friendly manner.The second part is the application of cercosporin derivatives to aryl esterification.We conducted conditional screening and explored the substrate range of aryl esterification,and proved that aryl bromides with different substituents can be acylated with benzoic acid,and the esterification can tolerate a variety of carboxylic acids.The wide selection of functional groups and substrates indicates that cercosporin derivatives have a greater advantage in the aryl esterification reaction.The third part is the preparation of new photocatalysts using cercosporin and transition metals,and attempts to use 9-oxycatechol combined with ruthenium,which is similar in structure to cercosporin,but relatively inexpensive and easy to prepare,and applied to ruthenium The selective oxidation reaction showed that the three complexes of 9-oxycatechol combined with ruthenium have good performance in amine oxides to aldehydes and oxidized sulfides to sulfoxides.We subsequently succeeded in synthesizing cercosporin and ruthenium in the same manner as 9-oxycatechol catechol,prepared three complexes,and explored their physical and chemical properties.