Heat-resistant and shape-memory metallo-supramolecules with simultaneously switchable fluorescence behavior supported by tridentate N3 group

Abstract 2,6-bis(N-pyrazolyl) pyridine (BPP) with tridentate N3 group is successfully incorporated into copolymer via solution polycondensation in this work. With assembly of different metal ions, the supramolecules could be shape-memorized or fluorescence-responsive. The tridentate N3 group in BPP fragment is found to enhance the fluorescence intensity of BPP-Eu3+ films and affinity to the metal ions, supported by inter-fragmented charge transfer theory (IFCT) and wavefunction analysis. The heat-resistance of supramolecules is improved by incorporation of zinc ions and the Tg could be changed from 150.5 °C up to 201.7 °C. The average binding strength (BDE) of N–Zn2+ in NMP solvation model is −5.03 kcal/mol, which is flexible enough to maintain the dynamic properties discussed in this study.