Solvent-free autocatalytic supramolecular polymerization.

Zhen Chen,Takuzo Aida,Yuki Omata,Yukinaga Suzuki,Atsuko Nihonyanagi,Kotagiri Venkata Rao,Ayumi Imayoshi,Emiko Sato,Xiaofan Ji,Daigo Miyajima

doi:10.1038/s41563-021-01122-z

Abstract

Solvent-free chemical manufacturing is one of the awaited technologies for addressing an emergent issue of environmental pollution. Here, we report solvent-free autocatalytic supramolecular polymerization (SF-ASP), which provides an inhibition-free template-assisted catalytic organic transformation that takes great advantage of the fact that the product (template) undergoes a termination-free nucleation-elongation assembly (living supramolecular polymerization) under solvent-free conditions. SF-ASP allows for reductive cyclotetramerization of hydrogen-bonding phthalonitriles into the corresponding phthalocyanines in exceptionally high yields (>80%). SF-ASP requires the growing polymer to form hexagonally packed crystalline fibres, which possibly preorganize the phthalonitriles at their cross-sectional edges for their efficient transformation. With metal oleates, SF-ASP produces single-crystalline fibres of metallophthalocyanines again in exceptionally high yields, which grow in both directions without terminal coupling until the phthalonitrile precursors are completely consumed. By taking advantage of this living nature of polymerization, multistep SF-ASP without/with metal oleates allows for the precision synthesis of multi-block supramolecular copolymers.

Highlights

We serendipitously found the basic principle of solvent-free autocatalytic supramolecular polymerization (SF-ASP) during a study on the ferroelectric nature of H-bonding PN derivatives[32], where green-colored thin fibers formed upon heating PNC4 (Fig. 1b) on a hot stage
We serendipitously found the basic principle of SF-ASP during a study on the ferroelectric nature of H-bonding PN derivatives[32], where green-colored thin fibers formed upon heating PNC4 (Fig. 1b) on a hot stage
By matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry (Fig. 2c, i), we found that the fibers obtained in 24 hours were composed of phthalocyanine HPCC4 (Fig. 1c), whereas no precursor PNC4 was detected

Summary

Introduction

We serendipitously found the basic principle of SF-ASP during a study on the ferroelectric nature of H-bonding PN derivatives[32], where green-colored thin fibers formed upon heating PNC4 (Fig. 1b) on a hot stage. We report solvent-free "autocatalytic" supramolecular polymerization (SF-ASP).

Results

Conclusion