Open MOFs with Unique Hexatopic Zinc-5,15-bis(4′-carboxyphenyl)-10,20-bis(3′,5′-dicarboxyphenyl)porphyrin Linker

Abstract

Characteristic coordination modes of tetrapodal and octapodal porphyrin linkers were combined in the design of a new hexapodal porphyrin linker. The custom-designed [(5,15-bis(4′-carboxyphenyl)-10,20-bis(3′,5′-dicarboxyphenyl)]porphyrin (H6HCPP) contains two trans-related 4-carboxyphenyl coordination sites similar to tetra(carboxyphenyl)porphyrin (H4TCPP) linker and two other 3,5-dicarboxyphenyl (isopthalate-type) functions related to octa(carboxyphenyl)porphyrin (H8OCPP) moiety. Synthesis of the H6HCPP was optimized for higher yields by utilizing excess concentration of TFA. The supramolecular reactions of zinc metalated linker Zn-H6HCPP with different metal centers afforded open hexacarboxy–metalloporphyrin frameworks (hcMPFs) perforated by wide intralattice voids. One 6-connected uninodal and two 6,6-connected binodal frameworks Mn-hcMPF (1), Co-hcMPF (2), and Zn-hcMPF (3) were obtained by employing transition metals Mn(II), Co(II), and Zn(II) as the exocyclic interporphyrin binding nodes. These framew...