Two-Dimensional Hydrogen Bond Networks Supported by CH/π Interaction Leading to a Molecular Packing Appropriate for Topochemical Polymerization of 1,3-Diene Monomers

Abstract

Strong and weak hydrogen bonds, as intermolecular interactions, are used for the construction of designer crystals with organic small molecules as the building blocks. We report here crystal engineering for the synthetic plan of the topochemical polymerization using the ammonium derivatives of 1,3-diene mono- and dicarboxylic acids on the basis of intermolecular interactions such as NH/O and CH/π interactions. The isomerism of hydrogen bond network structures obstructs the prediction of crystal structure and reactivity, although topochemical polymerization requires that monomer molecules stack in a column with a stacking distance of 5 Å in the crystals. The structures of hydrogen bond networks are roughly classified into a two-dimensional type appropriate for topochemical polymerization, and the others consisting of two-dimensional sheets or one-dimensional ladders not for polymerization. We conclude that the CH/π interaction of naphthylmethyl and benzyl substituents promises to give polymerizable lamella crystals, of which the interface is supported by robust two-dimensional hydrogen bond networks reinforced by lining with CH/π interaction between benzylic and aromatic hydrogens and π-electrons.