Effective enhancement of the emission efficiency of tetraphenylporphyrin in solid state by tetraphenylethene modification  

作　　者：Nan Jiang Yijia Wang Anjun Qin Jing Zhi Sun Ben Zhong Tang 

机构地区：[1]MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University [2]Guangdong Innovative Research Team, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology [3]Department of Chemistry, Institute for Advanced Study, Institute of Molecular Functional Materials, and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science & Technology

出　　处：《Chinese Chemical Letters》2019年第1期143-148,共6页中国化学快报（英文版）

基　　金：financially supported by the Key Project of the Ministry of Science and Technology of China(No.2013CB834704);the National Natural Science Foundation of China(No.51573158);the Research Grants Council of Hong Kong(Nos.16301614,N_HKUST604/14 and N_HKUST-620/11);the support of Guangdong Innovative Research Team Program(No.201101C0105067115)

摘　　要：Tetraphenylporphyrin(TPP) is a typical red-emitting luminogen showing evident aggregation caused quenching(ACQ) effect. To enhance its emission efficiency in solid state, four tetraphenylethene(TPE)units were attached to the four meso-positions of TPP core via ester group through a facile and efficient route. The derived compound(4(TPE-COO)-TPP) emits red fluorescence(peak at 655 nm) with a good quantum efficiency(F) of 7.5%, which is much higher than that of TPP(Φ～ 0.1%). In molecular aggregate formed in tetrahydrofuran(THF) and water mixtures, 4(TPE-COO)-TPP has a relative high F of 12%. The evidently subdued ACQ behavior can be ascribed to the propeller shape and bulky size of the TPE units,which prevent the close packing and strong p-p interaction of TPP cores. The loose molecular packing and weak interchromophore interactions were validated by different characterization methods including UV-visible absorption, steady state and transient fluorescence spectroscope, X-ray diffraction and scanning electronic microscope observations. It is noted that 4(TPE-COO)-TPP has an emission efficiency of 14.4% in dilute THF solution. This is due to the conjugation break between the TPP and TPE moieties, the rotational and vibrational motions of the phenyl groups cannot quench the fluorescence of 4(TPE-COO)-TPP.Tetraphenylporphyrin(TPP) is a typical red-emitting luminogen showing evident aggregation caused quenching(ACQ) effect. To enhance its emission efficiency in solid state, four tetraphenylethene(TPE)units were attached to the four meso-positions of TPP core via ester group through a facile and efficient route. The derived compound(4(TPE-COO)-TPP) emits red fluorescence(peak at 655 nm) with a good quantum efficiency(F) of 7.5%, which is much higher than that of TPP(Φ～ 0.1%). In molecular aggregate formed in tetrahydrofuran(THF) and water mixtures, 4(TPE-COO)-TPP has a relative high F of 12%. The evidently subdued ACQ behavior can be ascribed to the propeller shape and bulky size of the TPE units,which prevent the close packing and strong p-p interaction of TPP cores. The loose molecular packing and weak interchromophore interactions were validated by different characterization methods including UV-visible absorption, steady state and transient fluorescence spectroscope, X-ray diffraction and scanning electronic microscope observations. It is noted that 4(TPE-COO)-TPP has an emission efficiency of 14.4% in dilute THF solution. This is due to the conjugation break between the TPP and TPE moieties, the rotational and vibrational motions of the phenyl groups cannot quench the fluorescence of 4(TPE-COO)-TPP.

关 键 词：Aggregation-induced EMISSION Tetraphenylethene PORPHYRIN RED EMISSION Molecular PACKING 

分 类 号：O6[理学—化学]