Establishment Of Stacking Mode For Chromophores In Cocrystals And Study Of Optical Properties

With the growth of the influence for crystal engineering in regard to organic optical materials,preparation of cocrystal based on design of supermolecule gets more and more attention.Compounds with conjugated system usually present outstanding optical properties,cocrystal involving this kind of compounds will contribute to regulate luminescent behavior through understanding connection between stacking modes and optical properties of chromophore.In this paper,compounds with carbazolyl,anthracyl and pyrenyl groups were chosen as main object of study,15 cocrystal materials and 4 microtubes were prepared by using crystal engineering methods,and the relations between stacking modes and optical properties of chromophore were constructed,detailed results are as follows:(1)Aldol reaction and Friedel-Crafts acylation method were used to synthesize compounds with carbazolyl,anthracyl and pyrenyl conjugated groups,with the introduction of 1,4-DITFB and TCNB molecules,4 halogen cocrystals,7charge-transfer cocrystals and 4 microtubes were prepared by solvent evaporation and coprecipitation method,respectivly.Analysis of crystal structure and Hirsheld surface calculation reveals that π-π interaction forms structural unit of the subject and object and hydrogen bonds,C-H···π and C-N···π interactions concatenate them.(2)PXRD,DSC/TGA,IR,solid absorption and fluorescence detection were undertaken for 4 halogen cocrystals,the results indicate that the cocrystals have good phase purity,homogeneity and thermostability,intermolecular interactions have influence on IR and solid absorption.Cocrystals have long-time delayed fluorescence emission caused by introduction of Iodine atoms,which breaks the spin-forbidden transition,but aggregation quenching effect decreases the intensity of fluorescence emission.(3)PXRD,DSC/TGA,IR,solid absorption and fluorescence detection were explored for 11 charge transfer cocrystals,results imply that the cocrystals have good phase purity,homogeneity and thermostability,intermolecular interactions have influence on IR and solid absorption.Fluorescence emissions of 11 charge-transfer cocrystals shift to higher wavelength and the intensities increase because of the charge-transfer process.(4)PXRD,SEM and fluorescence detection were applied for 4 microtubes,results manifest that microtubes have same structure of relevant cocrystals,hollow tubular structure with length of 20-100 μm were found in microtubes,and fluorescence intensities increase.This microtube materials have potential applications in minitype optical instruments.