Enhancing Order and Porosity in a Highly Robust Tin(IV) Triphosphonate Framework

Metal organic frameworks (MOFs) are noted for crystallinity, stability, and porosity. For many industrial challenges though, beyond stability to pore activation, porous materials require high thermal and moisture stability. Here, we report a Sn­(IV) triphosphonate framework, CALF-28, that is highly robust and porous. CALF-28 was designed based on the known structure of a divalent metal phosphonate that was 2-fold interpenetrated. It has strong sustaining interactions but consequently rapidly precipitates, compromising crystallinity. Using methods to enhance order, and by analogy to the M­(II) analogue, insights to the structure are ascertained and corroborated by PXRD and gas sorption analysis. CALF-28 has a surface area >500 m²/g and is stable in water

Zn₇O₂(RCOO)₁₀ Clusters and Nitro Aromatic Linkers in a Porous Metal–Organic Framework

A new metal–organic framework, CALF-22 comprising Zn₇O₂(COO)₁₀ secondary building units and 2-nitro-1,4-benzenedicarboxylate, is reported. The porosity and gas adsorption of N₂, H₂, CO₂, and CH₄ are studied, and CALF-22 has a surface area in excess of 1000 m²/g. The stability of the larger zinc cluster and the effect of the nitro group on gas sorption are also studied