Structural variety of alkali 1,3,5-benzenetricarboxylate coordination networks emanated from wet and mechanochemical methods

Alkali metal-based coordination polymers are a promising alternative to transition metal-based systems, but this research area is still greatly underdeveloped mostly due to limited ability to predesign alkali metal-based structures. In this report we demonstrate a comprehensive study on the preparation of Li, Na, K, Rb and Cs-based 1,3,5-benzenetricarboxylates using both self-assembly in an aqueous solution and the solid-state synthesis driven by mechanical force. Interestingly, despite the apparent simplicity of the studied reaction systems, the prepared alkali-based coordination networks show great structural variety including diverse metal-linker ratios as well as hydrates of various stoichiometry. The demonstrated procedures allowed for detailed structural characterization of seven new alkali 1,3,5-benzenetricarboxylates. As an integral part of the study, solvent-free mechanochemical reactions aimed at the synthesis of the developed alkali-based coordination networks were investigated, which revealed that most of the studied materials can be prepared using this green solid-state protocol. Moreover, two of the studied materials could only be prepared in high yield via the mechanochemical approach which demonstrates the great potential of mechanochemistry as a tool for controlling complex self-assembly reaction systems.