Syntheses,Structures And Properties Of Solid-state Luminescent Molecules

Fluorescent dyes with the properties of aggregation induced luminescence(AIE)have been developed abundantly in recent years.Different research groups have explored a variety of AIE systems,and are continuously expanding their design ideas and application fields.Combining AIE properties with other special luminescent properties to construct organic small molecules and to explore their practical application values are the currently research hotspot of AIE materials.Based on this,we designed and synthesized a series of AIE molecules with different luminous properties and studied their applications.We carried out a series of works as follows:(1)Organic molecules which have D-A structure often involve significant intramolecular charge transfer(ICT),they are also expected to exhibit solvatochromism.Three dyads(DCB-H,DCB-Br and TCB-H)are designed and synthesized from two different fused carbazole-based aromatic cores(D)and peripheral benzophenone units(A).All the molecules showcase solvatochromism that originate from the ICT character.Because of the unique propeller-like structure,all of them have AIE property.Moreover,it can be used as a fluorescent probe to detect trinitrophenol(PA)in explosives.(2)Squaric acid has a structure of electron-deficient four-membered ring,which can reaction with electron donor to form D-A-D system.Based on the squaric dyes(SQDs)with both AIE and fluorochromic properties have not yet been explored.Herein,we introduced the halogenated diphenylamine derivatives to the squaric acid through facile condensation reactions,which impart AIE and fluorochromic properties to the SQDs.The obvious AIE properties stem from the unique propeller structure in single crystals.Interestingly,halogens can modulate the electronic and crystalline configuration.We found that different halogen-substituted acid derivatives have different luminescent properties,such as mechanochromism,vapochromism,etc.All of them have good recyclability.This strategy that AIE and fluorochromic properties by the halogen modulation exploit a new approach in exploring fluorescent materials.