Thermodynamic, kinetic, and structural factors in the synthesis of imine-linked dynamic covalent frameworks

The formation of imine-linked dynamic covalent frameworks (DCFs) has been systematically studied to determine how different factors such as reaction solvent and composition, reaction kinetics and thermodynamics, and structure of the building units influence the yield, degree of condensation, and homogeneity of the resulting products. Using molecular tetraimine analogs, we first investigated the kinetics and thermodynamics of imine condensation reactions under a variety of conditions, as well as the structures of the basic tetraimine units by X-ray crystallography. These model systems allowed us to identify conditions that favored both high reversibility and fast reaction kinetics for the imine condensation, leading in the end to the development of effective synthetic routes toward imine-linked DCFs with high degrees of cross-linking and homogeneity. (C) 2011 Elsevier Ltd. All rights reserved.