Interplay between chalcogen bonds and dynamic covalent bonds

Abstract

Chalcogen bonds as a type of supramolecular interactions have been attracting increasing attention, and studies on their regulating mechanisms are of importance. Herein, we demonstrate the interplay between chalcogen bonds and dynamic covalent chemistry (DCC) toward the investigation of chalcogen bonding and control over imine systems. The intramolecular Chal⋯O/N chalcogen bonding was revealed to modulate the conformational preference of ortho-chalcogen benzaldehydes and associated imines. The role of chalcogen bond in shifting dynamic imine exchange was systematically studied, with chalcogen bonding significantly decelerating the kinetics, while thermodynamically stabilizing the imines. Computational studies further unraveled mechanistic insights for chalcogen bonding, with orbital and electrostatic interactions accounting for the major contribution. Moreover, orbital interaction mainly makes up the difference from S to Te, and tellurium enables the strongest interaction, in line with the largest effect of Te on the movement of the imine exchange equilibrium. By utilizing the effects of chalcogen bonds on imine DCC, the reversal of the thermodynamic and kinetic selectivity of dynamic covalent systems was controlled. The results should open up opportunities for molecular recognition, dynamic assemblies, catalysis, and associated endeavors.