Porphyrin-based metal-organic frameworks on surfaces are a new class of planar materials with promising features for applications in chemical sensing, catalysis, and organic optoelectronics at nanoscale. Herein, we studied systematically a series of the SURMOFs assembled from variously meso-carboxyphenyl/pyridyl-substituted porphyrins and zinc acetate on template monolayers of graphene oxide via layer-by-layer deposition. This microscopically flat template can initiate the growth of macroscopically uniform SURMOF films exhibiting well-resolved X-ray diffraction. By applying the D'yakonov method, which has been previously used for the extraction of self-convolution of electron density in clay minerals, to the analysis of the experimental diffraction patterns of the SURMOFs, we determined the relation between the structure of porphyrin linkers and the geometry of packing motives in the films. We showed that the packing of the SURMOFs differs significantly from that of bulk powders of similar composition because of steric limitations imposed on the assembly in 2D space. The results of microscopic examination of the SURMOFs suggest that the type of metal-to-linker chemical bonding dictates the morphology of the films. Our method provides an enlightening picture of the interplay between supramolecular ordering and surface-directed assembly in porphyrin-based SURMOFs and is useful for rationalizing the fabrication of various classes of layered metal-organic frameworks on solids.
Intermolecular interactions in thin films of organic dyes control the enhancement of the optical absorption by collective plasmons of gold nanoparticles.
A strategy for rational design of synergetic hybrid materials exploiting stabilization of intercalated layered matrices via coordination bonding is described. A new hybrid material is assembled through subsequent intercalation of the surface‐anchored metal–organic framework (SURMOF) components, zinc acetate and 5,10,15,20‐tetrakis(4‐carboxyphenyl)‐porphyrin‐zinc(II) (ZnTCPP), into the layered europium(III) hydroxychloride (LEuH). The formation of the SURMOF clusters intercalated in LEuH is confirmed by X‐ray diffraction, FTIR and Raman spectroscopy, and BET nitrogen absorption methods. The catalytic function of the SURMOF/LEuH hybrid and its components in the model reaction of hydrolysis of bis(4‐nitrophenyl) phosphate in the acidic solution is studied by UV–vis and MALDI‐TOF spectroscopy. Both the non‐intercalated matrix and the MOF powder are inactive and unstable in the substrate solution. Unlike its components, the SURMOF/LEuH hybrid exhibits synergetic catalytic activity increasing with the amount of the intercalated compounds because of the mutual stabilization of the components through coordination interactions. The results provide a basis for symbimetic (mimicking the symbiotic behavior in biological systems) hybrid materials, in which stabilization of functional units in the intercalated structure translates into a synergy of useful properties.
Controlled
self-assembly and rapid disintegration of supramolecular
nanowires is potentially useful for ecology-friendly organic electronics.
Herein, a novel method exploiting the binding between crown-substituted
double-decker lanthanide phthalocyaninates (ML2, M = Lu,
Ce, Tb) and K+ ions is applied for the one-step fabrication
of macroscopically long conductive one-dimensional quasi-metal–organic
frameworks. Their properties are controlled by the size of the lanthanide
ion guiding the assembly through either intra- or intermolecular interactions.
A LuL2 linker with a small interdeck distance yields fully
conjugated intermolecular-bonded K+–LuL2 nanowires with a thickness of 10–50 nm, a length of up to
50 μm, and a conductivity of up to 11.4 S cm–1, the highest among them being reported for phthalocyanine assemblies.
The large size of CeL2 and TbL2 leads to the
formation of mixed intra- and intermolecular K+–ML2 phases with poor electric properties. A field-assisted method
is developed to deposit aligned conductive K+–LuL2 assemblies on solids. The solid-supported nanowires can be
disintegrated into starting components in a good aprotic solvent for
further recycling.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.