Competition in formation of stimuli-responsive metallogel and coordination polymers from a single precursor: synthesis, characterization and catalytic application

Abstract

The synthesis, structure, and catalytic properties of a new 2D crystalline coordination polymer (Zn-CP1) as well as a stable new low molecular weight metallogel (Zn-G1) are reported. Interestingly, both types of materials can be synthesized using the same amino acid based chiral ligand (PV) and Zn2+ ion. Precisely, pure organic solvent (MeOH) prompts gelation while DMF-water medium favours the formation of coordination polymer (CP). Hence, the nature of the solvents and metal counter anion used, play a crucial role in gel formation. Both the CP and gel were characterized by various spectroscopic and analytical techniques such as PXRD, FT-IR, TGA, SEM, and dynamic rheology. Structural analysis of Zn-G1 reveals an entangled spongy-like fibrous network in which spongy patches consist of micro fibres within the matrix of the supramolecular metallogel, while the structural analysis of Zn-CP1 revealed the formation of a 2D sheet-like structure. The Zn-G1 exhibits remarkable stimuli-responsive behaviour towards temperature, mechanical force, and chemicals; however, the Zn-CP1 was found to exhibit promising catalytic activity over Zn-G1 for the conversion of CO2 to cyclic carbonate from various epoxides.