Functional group tolerance in BTB-based metal–organic frameworks (BTB – benzene-1,3,5-tribenzoate)

• Three derivatives of a trigonal linker were tested in isoreticular MOF synthesis.
• Three new isoreticular compounds could be identified.
• Two new compounds with differing topology from the parent MOFs could be identified.
• The substituents demonstrated great impact on the definite framework topology.

The effect of different substituents on the structural tolerance of benzene-1,3,5-tribenzoate (BTB) based MOFs was studied. For this purpose, three new BTB derivatives ((NH2)3-BTB, tri((tert-butoxycarbonyl)-amino)-BTB; tri((S)-2-acetoxy-2-phenylacetamido)-BTB) were synthesized and utilized in MOF synthesis using synthetic conditions established for eight known MOFs. Three new isoreticular compounds (NH2-DUT-6, NHBoc-DUT-25, mand-DUT-25) could be identified. Furthermore, two compounds with network topologies differing from the parent compound comprising NHBoc-BTB and Cu-paddlewheels as nodes were found: Cu2(H2O)2(H(NHBoc)-BTB)2 (1), a dense structure containing layers with sql topology, and Cu3(H2O)(NHBoc-BTB)2(bipy) (bipy – 4,4′-bipyridine, DUT-109), with crosslinked iab-network. The porosity of DUT-109 was proven by liquid phase adsorption of ethyl cinnamate from n-heptane. In general, a significant influence of the BTB substituent on the framework formation could be demonstrated.

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