Synthesis of a Chiral 3,6T22-Zn-MOF with a T-Shaped Bifunctional Pyrazole-Isophthalate Ligand Following the Principles of the Supramolecular Building Layer Approach.

The metal-organic framework (MOF) [Zn(Isa-az-tmpz)]·1-1.5 DMF with the novel T-shaped bifunctional linker 5-(2-(1,3,5-trimethyl-1H-pyrazol-4-yl)azo)isophthalate (Isa-az-tmpz) was obtained as a conglomerate of crystals with varying degrees of enantiomeric excess in the chiral tetragonal space groups P422 or P422. A topological analysis of the compound resulted in the rare -topology, deviating from the expected -topology, which has been found before in pyrazolate-isophthalate-functionalized MOFs using the supramolecular building layer (SBL) approach. -[Zn(Isa-az-tmpz)]·1-1.5 DMF is a potentially porous, three-dimensional structure with DMF molecules included in the corrugated channels along the and -axis of the as synthesized material. The small trigonal cross-section of about 6 × 4 Å (considering the van der Waals surface) prevents the access of N and Ar under cryogenic conditions. After activation, only smaller H (at 87 K) and CO (at 195 K) are allowed for gas uptakes of 2 mmol g and 5.4 mmol g, respectively, in the ultramicroporous material, for which a BET surface area of 496 m·g was calculated from CO adsorption. Thermogravimetric analysis of the compound shows a thermal stability of up to 400 °C.