Supramolecular structures and molecular self-assembly under hydrogen bonded and/ or metal coordinated case studies: from benzoxazines to diacetylenes

Abstract

The present work focuses on molecular design and development of molecular self-assembly via hydrogen bond network and/ or metal coordination through the case studies on benzoxazines and diacetylenes. In the first part shows the unique molecular design of benzoxazines by using diamines so that the ring opening structured diamine-based benzoxazine dimers favour the continuous hydrogen bond network and metal complexation. By simply varying hydrophobic (methylene) bridge length and concentration, the self-assembly of diamine-based benzoxazine under hydrogen bond network can be clarified and also performed the various morphologies. Not only formation of hydrogen bonding but also coordination with metal ion, the diamine-based benzoxazines are proved to be supramolecular polymer via both hydrogen bonding and metal-ligand complexation which have been rarely seen. From this study, the diamine-based benzoxazine dimer can be noticed to be one of the choices for modifying terminated moiety of macromonomer in order that chain growth can be able to form supramolecular polymers. In the final part, the work covers supramolecular structures of diacetylene derivatives (diarylbutadiyne) which topochemical polymerization can be carried out. In fact, the successful cases of diarylbutadiyne solid state polymerization are few reported. This work shows the effect of substituted positions (ortho-, meta-, and para positions) of conjugated amide under photon irradiation. Hydrogen bond network of amide unit is used for preforming structures to reach the optimum packing, favouring the topochemical polymerization. The solid state polymerization of N,N'-(3,3'-(buta-1,3-diyne-1,4-diyl)bis(3,1-phenylene))diheptanamide (mDA) is faster than the others, whereas N,N'-(4,4'-(buta-1,3-diyne-1,4-diyl)bis(4,1-phenylene))diheptanamide (pDA) is not polymerized under the light. The total change in volume of polymer and monomer crystals is clarified to explain the possibility of their topochemical polymerization.