Ortho-Position Functionalized Perylenes And Corresponding Cyclopenta-fused Polycyclic Aromatics

Perylene is one of the classic polycyclic aromatic hydrocarbon molecules.Perylene and its derivatives have wide potential applications in the fields of organic light-emitting diodes,organic solar cells and organic photosensitive dyes due to their special physical properties.Unfortunately,direct chemical modification of perylene is difficult and non-selective,especially in the ortho-position,which extremely limited the development of perylene functionalized molecules.Among the perylenes,perylene-3,4,9,10-tetracarboxylic acid diimides(PDIs)were most studied,its functional modification is also a challenging problem.It is of great significance to develop new perylenes and enrich the types of perylene.It is worth noting that the cyclo-penta fused polycyclic aromatic hydrocarbon is a widely recognized and potential organic functional molecular material due to its unique physical properties such as electron acceptor ability and low energy band gap.(1)Based on the parent perylene Per-4Br,we have explored the compatibility of the substitution reaction and suzuki coupling reaction.Various ortho-substituted perylenes containing cyano,methoxy and aryl groups,were then synthesized via nucleophilic substitution or Pd-catalyzed coupling reactions.The experimental results show that the substituent effect of the ortho-position gave the interesting tunable optoelectronic properties and provided the possibility to constructing high-order functional molecules.(2)Based on the Per-4OMe,fused five-member rings have been introduced at the peri-position,giving the diindenoperylene derivatives.The experimental results showed that the introduction of the five-membered ring and the substituent of the conjugates(phenylethynyl group)can lower the HOMO and LUMO levels of the compound and also reduce the band gap.This not only endows polycyclic aromatic hydrocarbons a good electron accepting ability,but also provides a new class of functional molecular materials with narrowed band gap.(3)For further extending the conjugated system,we designed a diindeno quaterrylene derivative,and could provide an interesting near-infrared dye with promising organic electronic characters.We successfully obtained the cyclized precursor,with which favorable construction of higher-order five-member ring fused rylenes.In addition,we discussed its possible physical properties based on the theoretical predictions.