A 3D Synthesis Strategy for Pyrene-Based Fluorescent Conjugated Polymers and Application in Picric Acid Sensing

摘要

In this work, l,3,6,8-tetrakis(4-formylphenyl)pyrene (TFPPy) was synthesized and used as polymer precursor, and then two kinds of fluorescent conjugated polymers (CPs) are synthesized through Schiff base reactions with two kinds of tri-amine as the other part of precursor, namely CPshu-1 and CPshu-2, respectively. By using D_2h symmetry tetra-aldehyde and C_3 symmetry tri-amine as precursors, aggregation-caused quenching (ACQ) of fluorophore can be reduced to minimum, to make the greatest fluorescent sensing performance. The resulting CPs were firstly characterized by Fourier transform infrared spectroscopy (FT-IR), solid-state ~(13)C nuclear magnetic resonance (~(13)C NMR). The morphology of resulting CPs were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Fluorescent spectra indicated that the sample showed orange luminescene at around 610nm. Before detecting the sensing performance, the CPs were firstly dispersed into acetonitrile to make a 1 mg/mL suspension, and the suspension showed a high sensitive to picric acid (PA). The suspension of CPshu-1 was totally quenched at a PA concentration of 5.2×10~(-4) M, and the limit of detection was calculated to be 3.18 ppm. For CPshu-2, the suspension was totally quenched at a PA concentration of 3.5×10~(-4) M, and the limit of detection was calculated to be 2.11 ppm. This work demonstrated that we can design 3D polymer structure to avoid ACQ negative effects, and build high performance fluorescent chemosensing materials.