Polymerization, Stimuli-induced Depolymerization, and Precipitation-driven Macrocyclization in a Nitroaldol Reaction System

Abstract

Dynamic covalent polymers of different topology have been synthesized from an aromatic dialdehyde and α,ω-dinitroalkanes via the nitroaldol reaction. All dinitroalkanes yielded dynamers with the dialdehyde, where the length of the dinitroalkane chain played a vital role in determining the structure of the final products. For longer dinitroalkanes, linear dynamers were produced, where the degree of polymerization reached a plateau at higher feed concentrations. In the reactions involving 1,4-dinitrobutane and 1,5-dinitropentane, specific macrocycles were formed through depolymerization of the linear chains, further driven by precipitation. At lower temperature, the same systemic self-sorting effect was also observed for the 1,6-dinitrohexane-based dynamers. Moreover, the dynamers showed a clear adaptive behavior, displaying depolymerization and rearrangement of the dynamer chains in response to alternative building blocks as external stimuli.

Spontaneous and Selective Macrocyclization in Nitroaldol Reaction Systems

“…Hence, in this study, a range of new nitroaldol dynamerization systems, potentially able to produce macrocycles, were investigated. 73 The reactions of three aromatic dialdehydes with 11 dinitro-compounds (aliphatic and aromatic) were explored, where several new macrocyclic species were isolated and identified.…”