Self-assembly of sterically-rigidified 3-connecting benzenetribenzoic acid into (6,3) and (3,3) nets and stabilization of water channel in the crystal lattice†
Abstract
A rigid 3-connecting triacid MeBTB was designed and synthesized in the quest of guest inclusion in the pores of honeycomb network structures generated based on the acid dimer-mediated self-assembly. Crystallization of MeBTB is indeed found to lead to a (6,3) net that is 3-fold interpenetrated. Charge-assisted hydrogen bond-mediated self-assembly in the presence of KX/dibenzo-18-crown-6 is likewise found to lead to a (3,3) honeycomb net, which is also 3-fold interpenetrated. When contrasted with the results of self-assembly of sterically-unhindered 1,3,5-benzenetribenzoic acid 2 and those of analogous tribenzoic acid based on mesitylene, that is MTB, the sterics built into the structure of MeBTB allow engineering of ordered assemblies with reduced interpenetration and higher solvent-accessible volumes. A limited, yet meaningful number of structures demonstrates the fact that the rigid building blocks, while responding to the expectations based on aggregation via acid dimer synthon, are most likely to present rich diversity in terms of synthon adoptions and bring up surprises in the self-assembly through inclusion of adventitious water. Crystallization of MeBTB in MeOH–DME led to a disappearing solvate form in which the helically organized acids are found to sustain a water channel.
- This article is part of the themed collection: International Year of Crystallography Celebration: India