Hydrogen bonding mediated self-assembly of a barbituric acid-containing macrocyclic diacetylene

Abstract

Since Wagner's pioneering approach to polydiacetylenes (PDAs), the exploration of their self-assembly and conjugation behaviours have attracted sustained research interest. This study investigates the self-assembly and photopolymerisation behaviours of a macrocyclic diacetylene containing barbituric acid (MCDA-BA). By utilising hydrogen bonding and pi-pi stacking interactions, MCDA-BA forms well-defined supramolecular assemblies. The synthesis of MCDA-BA was confirmed through NMR, HRMS, and FTIR analyses. The self-assembled structures showed considerable variation under different conditions, which significantly influenced the photopolymerisation efficiency and the resulting nanostructures. FTIR and X-ray diffraction analyses revealed changes in hydrogen bonding states and stacking patterns. Upon UV irradiation, MCDA-BA exhibited distinct colour transitions from green to red, indicating topochemical polymerisation. The polymerised form, MCPDA-BA, demonstrated a robust ene-yne backbone and tubular morphology. This research highlights the ability to control self-assembly and photopolymerisation by manipulating hydrogen bonding, offering valuable insights for developing functional supramolecular materials with tailored properties for applications in nanotechnology and materials science.