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 frameworks feature dinuclear Mn2 and Zn2 paddlewheels in 1 and 3, and trinuclear Co3 trigonal prisms in 2, as inorganic building units. Among p-block elements In­(III) from the 13th group and Pb­(II) from the 14th group of the periodic table form In-hcMPF (4) and Pb-hcMPF (5) frameworks tessellated by InNa2 and Pb2 clusters as building units. Similar reactions with rare earth elements yielded the formation of Ln-hcMPFs (Ln = Pr­(III), Gd­(III), and Yb­(III)) structures (6–8) stabilized by one-dimensional {Ln­(COO)5Na2(H2O)2(μ2-H2O)2} n heterometallic helical chains with tetragonal shaped interporphyrin channel voids in 6 and 7 and homometallic dinuclear Yb2 cluster in 8. All the frameworks are noninterpenetrated and provide wide solvent accessible intralattice voids, which account for about 53–64% of the crystal volume. Thermal and powder diffraction analyses provided additional insights into the homogeneity and stability of these frameworks.

Porphyrin nanotubes based on a hydrogen-bonded organic framework

“…The ester groups in 2 were hydrolyzed with aqueous KOH and then acidified with dilute HCl to yield 3 (80%). 63 This was proved by MALDI-TOF MS; the parent ion peak was observed at m / z 2268.39, and calculated for C 138 H 78 N 12 Ni 3 O 12 : 2268.39. Moreover, the COOH functionality in 3 was confirmed by both FTIR and 1 H NMR spectra, and the carboxyl proton signal was observed at 10.56 ppm.…”

Metal‐organic Frameworks Incorporating Multiple Metal Elements

“…prepared a zwiterionic MOF composed of a cationic Fe(III) or Mn(III)‐porphyrin with a [In(CO 2 ) 4 ] − cluster, and they tested it in electrocyclization reactions . Tripuramallu et al . used a hexatopic porphyrin linker denoted HCPP (5,15‐bis(4′‐carbomethoxyphenyl)‐10,20‐bis(3,5‐biscarboethoxyphenyl)porphyrin) in combination with SBUs formed by 3d (Mn or Co), 4f (Pr, Gd or Yb), or 4d (Pb or In) metal elements.…”

N-doped porous carbons derived from Zn-porphyrin-MOF

“…Many custom-made porphyrins can generate por-MOFs with interesting topological structures and unique properties. 4,5 Very recently, Zhou et al have reported a series of por-MOFs using Zr IV -based UiO-66 analogues. 6,7 One of the advantages of using porphyrin bridging ligands might be their large physical dimensions.…”