Solvent-free autocatalytic supramolecular polymerization

Abstract Solvent-free chemical manufacturing is one of the awaited technologies for addressing an emergent issue of serious environmental pollution. Here, we report "solvent-free autocatalytic supramolecular polymerization (SF-ASP)", where a phthalonitrile derivative with hydrogen-bonding side chains as the monomer is autocatalytically transformed into the corresponding phthalocyanine in an exceptionally high yield (> 80%). The target phthalocyanine, if any is produced, nucleates and initiates supramolecular polymerization via a hydrogen-bonding interaction, affording one-dimensional single-crystalline fibers. These crystalline fibers possibly preorganize the precursor phthalonitrile monomer at their cross-sectional edges and autocatalytically convert them into the phthalocyanine under out-of-equilibrium conditions. In the presence of metal oleates, SF-ASP autocatalytically affords single-crystalline fibers of metallophthalocyanines again in exceptionally high yields. In these cases, such fibers grow in both directions without terminal coupling until the precursor phthalonitrile is completely consumed. By taking advantage of this quasi-living character of polymerization, multistep SF-ASP without/with metal oleates affords multi-block supramolecular copolymers.