The discovery of naturally occurring linker-based zirconium MOFs with permanent porosity and accessible functional groups remains a challenge. Using trans-aconitic acid to assemble with Zr 6 oxoclusters under green and scalable conditions, a novel microporous Zr-aconitate framework has been prepared successfully with a high space-time yield. This MOF is isostructural to the previously reported Zr-fumarate, however with a smaller pore size and an abundant concentration of free
IntroductionZirconium metal-organic frameworks (MOFs) have been intensively investigated and developed over the last decade, mainly due to their improved stability compared to most of the other metal cations-based MOFs. [1] Among diverse organic linkers used for Zr-MOFs, the majority are artificially synthetic ones, including most of the aromatic multi-carboxylic acids, [2] phenolates [3] and phosphonates. [4] In sharp contrast to artificial linkers, naturally occurring ones display numerous advantages, such as low toxicity and bio-compatibility, cost-effective, easy and abundant availability, which fulfil the sustainable development criteria. Nevertheless, there are very limited examples of Zr-MOFs constructed from naturally occurring linkers. Indeed only the three-dimensional (3D) Zr-Fumarate (also known as MOF-801) [5] and 2D Zr-formate, [6] have been reported so far. The 3D Zr-Fumarate is of particular interest due to its UiO-66 type rigid micropore system. [7] It was reported as a promising material in applications including water harvesting [8] and removal of fluoride contaminant. [9] The incorporation of functional groups into [a]