Pillared Porphyrin Homologous Series: Intergrowth in Metal−Organic Frameworks

Abstract

We report three new porphyrin-based, pillared paddle-wheel homologous series: porphyrin paddle-wheel frameworks PPF-3, -4, and -5. These compounds are assembled from free base or palladium tetrakis(4-carboxyphenyl)porphine, M(NO(3))(2) (M = Co and Zn), and 4,4'-bipyridine via solvothermal reactions. The resulting solids exhibit 3D metal-organic frameworks, where 2D layers are pillared by bipyridine with three different packing arrangements.

Porous Porphyrin Nanoarchitectures on Surfaces

“…[68] An in-plane structural motif of NAFS-1 comprising CoTCPP units linked by binuclear Cu 2 (COO) 4 paddle wheels ( Figure 12) and resulting in a similar checkerboard pattern to that encountered in the bulk PPF series leads to a simulated in-plane XRD profile, which is in good agreement with that observed experimentally ( Figure 11). The lattice size (1.65 nm), which is comparable to those of the PPF systems (1.66-1.67 nm), [68] as well as the results of XPS and IR spectroscopic measurements (Figures 7 and 8) support a NAFS-1 structural model in which binuclear paddle-wheel units are present and provide the necessary linker motifs to develop the 2D order of the film. Further detailed structural analysis was driven by the motivation to address another important question: "Why is the interlayer spacing of 0.94 nm -extracted from the structural analysis of the out-of-plane XRD profile -considerably smaller than the estimated layer thickness of approximately 1.24 nm, if stacking of the layers is driven exclusively by physical adsorption?"…”

“…[68][69] Stacking sequences were controlled by utilizing different metal-centered porphyrins, MTCPP (M = Co 3+ , Zn 2+ , Pd 2+ ), in which the coordination number of the metal site is varied from six (octahedral geometry, Co 3+ ) to five (square-pyramidal geometry, Zn 2+ ) and to four (square-planar geometry, Pd 2+ ), while a 2D "checkerboard" in-plane linkage pattern remains the same for all analogues. [68] An in-plane structural motif of NAFS-1 comprising CoTCPP units linked by binuclear Cu 2 (COO) 4 paddle wheels ( Figure 12) and resulting in a similar checkerboard pattern to that encountered in the bulk PPF series leads to a simulated in-plane XRD profile, which is in good agreement with that observed experimentally ( Figure 11). The lattice size (1.65 nm), which is comparable to those of the PPF systems (1.66-1.67 nm), [68] as well as the results of XPS and IR spectroscopic measurements (Figures 7 and 8) support a NAFS-1 structural model in which binuclear paddle-wheel units are present and provide the necessary linker motifs to develop the 2D order of the film.…”

3-Hydroxynaphthalene-2-carboxylic acid supported grid-like structure of cadmium chloride coordination polymer with 1,3-bis(4-pyridyl)propane

“…In general, adequately directed rigid bidentate ligands form such structures [25]. On the other hand, flexible bidentate ligands easily form grid-like [26][27][28], interpenetrating and helical [1,29] structures. Flexible bidentate ligands forming grid-like structures can show tunable porosity [26][27][28], chirality [1,29] and dynamic porosity [30].…”

Self-assembly of iron TCPP (meso-tetra(4-carboxyphenyl)porphyrin) into a chiral 2D coordination polymer

“…Additionally, the combination of TCPP with other components gives rise to a variety of 2D and 3D structures [25]. Some of these combinations are specially remarkable as they include fullerene [26], silica [27] and 4,4´-bipyridine [28][29]. During the last years, our research has been focused on the preparation of coordination polymers with increasing dimensionality with a variety of metal-ligand combinations, and we have prepared several high dimensional structures with 4,4´-bipyridine, including interpenetrated networks [30][31][32][33][34][35].…”