The role of shape and interaction directionality in the crystalline phase behaviour of octahedral metal-organic cages

Abstract

Despite advances in crystal engineering, predicting the packing of metal-containing molecules remains a significant challenge due to their increased structural complexity and computational cost relative to purely organic compounds. Yet, predicting solid-state structures is critical for understanding structureproperty relationships, particularly in modular porous systems such as metal–organic cages (MOCs), where packing governs access to the internal pores and thereby impacts functionality. Here, we present a computationally inexpensive methodology that combines semi-empirical dimer calculations with coarse-grained modelling to predict the packing behaviour of MOCs. This approach enables a priori prediction of the solid state and allows insight into how molecular shape and intermolecular interactions influence the crystalline phase behaviour of MOCs. Our findings provide a foundation for the rational design of MOCs with tailored solid-state structures and properties.