Syntheses And Properties Of Two-photon Fluorescent Organic Microporous Polymers

Recent years, microporous organic polymers（MOPs）have attracted considerableinterest in the fields such as gas storage, molecule separation, catalyst and its supports dueto their large specific surface area, high thermal stability and low skeleton density. Herein,from the viewpoint of developing novel opto-electronic functional materials, two newmicroporous organic polymers named CBF and MBP were synthesized through Suzukicross-coupling using1,3,5-triphenylbenzene/biphenyl and bithiophene/biphenyl asbuilding blocks respectively. The morphology, structure and spectral properties of theas-prepared CBF and MBP polymers were characterized using a series of methods such asfield emission scanning electron microscopy（FESEM）,solid-state nuclear magneticresonance（NMR）, fluorescent spectroscopy and two-photon femtosecond laser excitationfluorescence. The results are as follows.（1）The as-obtained CBF sample is measured to be thermally stable up to400℃and amorphous. The surface area and average pore diameter were calculated to be9.96m2·g-1and1.88nm using BET and NLDFT, respectively. When excited by light of315nm, CBF emits a solid-state green luminescence centered at425nm. The emissioncolor of CBF can change from green to red with the increasing of the wavelength ofone-photon excitation light. And an obvious two-photon fluorescence was observable fromCBF upon excitation by an800nm fs laser.（2）It is demonstrated that the as-prepared MBP product is thermally stable up to460℃and amorphous. The surface area and average pore diameter were calculated to be365m2·g-1and1.67nm using BET and NLDFT, respectively. MBP emits a solid-stategreen luminescence centered at530nm when excited by345nm UV light with thequantum efficiency φFL=0.78%upon excitation at430nm where the UV absorptioncurve of MBP exhibits the strongest absorption peak. The emission color of MBP canchange from green to red with the increasing of one-photon excitation light. And a moreobvious two-photon fluorescence was observable from MBP upon excitation by an800nm fs laser. In summary, Two two-photon fluorescent microporous organic polymers with thenames of CBF and MBP were successfully designed and prepared using Suzukicross-coupling as a polymerization technique. And MBP shows a higher adsorptivecapacity and more excellent spectral properties comparing with CBF. The uniquemicroporous structure and two-photon fluorescent property CBF and MBP possessdemonstrate a tremendous potential application in the fields such as novel opto-electronicfunctional materials and biolabelling.