Anionic zinc-trimesic acid MOFs with unusual topologies: Reversible hydration studies

The reaction of 1,3,5-benzenetricarboxylic acid (H3BTC) with ZnSO4·6H2O in a DMF–water solution afforded two new metal–organic frameworks [Zn6(μ3-OH)2(BTC)4(DMF)2.5(H2O)2]·[Zn(H2O)3(DMF)3]·3.1H2O (1) and Zn2(HBTC)(BTC)(H2O)3]·DMA·3H2O (2). Both compounds are thermally stable and can be prepared reproducibly. Rehydration experiments on compound 2 demonstrate reversible dehydration and rehydration while 1 rehydrates to a different crystalline material. Network analysis revealed a binodal (3,6)-net for 1 and a (3,5)-net for 2, both rare topologies.