Crystallization process development of metal-organic frameworks by linking secondary building units, lattice nucleation and luminescence: insight into reproducibility

The interdependence of crystallinity, secondary building unit (SBU) formation, linker vacancy, crystal habit, photoluminescence, and surface area for UiO-66 and In-MIL-68, respectively, produced by different processing modes has been fully investigated and linked together to comprehend the relationships among SBU synthesis pathways, structures, and functional properties. The solid-state properties of UiO-66 were found to be process-sensitive, but those of In-MIL-68 except for crystal habits were mode independent, most likely due to the versatile Zr₆(μ₃-O)₄(μ₃-OH)₄(CO₂)₁₂ SBU formation steps with more competing events for UiO-66 and the relatively straightforward {In(μ-O₂CR)₂(μ-OH)}_∞ chain SBU formation steps for In-MIL-68. The reproducibility of the desired properties of metal-organic frameworks (MOFs) relies on the crystallization process designed for specific SBU formation and nucleation trajectory.