Temperature-directed topology control in zirconium acetylenedicarboxylate MOFs through green aqueous synthesis

A green-chemical route using water/acetic acid as the solvent/modulator is proposed for obtaining the [Zr₆(µ₃-O)₄(µ₃-OH)₄(ADC)₆] MOF at 85 °C (Zr-HHUD-1; a UiO-66 analog with a face-centered cubic fcu topology, where ADC = acetylenedicarboxylate) and the alternative novel [Zr₆(µ₃-O)₄(µ₃-OH)₄(OH)₃(ADC)₄(H₃CCOO)(H₂O)₃] MOF at room temperature (Zr-HHUD-7; body-centered cubic bcu topology). Zr-HHUD-7 possesses two differently sized decorated pores, demonstrating higher IAST selectivity for CO₂ over CH₄ adsorption compared to Zr-HHUD-1. The temperature of synthesis is thus disclosed to control the degree of {Zr₆}-cluster connectivity, thereby enabling the tuning of the topology and sorption properties of zirconium-based metal-organic frameworks.