Surface etching of HKUST-1 promoted via supramolecular interactions for chromatography

Abstract

The addition of guanidinium-based surfactants to the synthesis of HKUST-1 reveals a novel surface patterning effect where meso-and macroscopic features appear on the MOF crystals. The size of the features increases with increasing alkyl chain length of the guanidinium amphiphiles, and their formation is strongly dependent on the presence of water which appears to more favourably etch the crystal surfaces when the surfactants are employed. The patterned crystals display intermediate type I/IV isotherms and the presence of the surface features have been evaluated for the chromatographic separation of styrene and ethylbenzene. Some degree of control over the interactions between the framework building blocks and the amphiphiles is afforded, and by simply changing the order of addition of the reactants the guanidinium surfactants promote the formation of HKUST-1 nanoparticles.

Enhanced Photoluminescence of Mesostructured Organosilica Films with a High Density of Fluorescent Chromophores

“…Mesostructured and mesoporous organosilica materials have attracted much attention because of their high applicability to optical materials, electronic devices, adsorbents, solid cata lysts, and biomedical uses. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] The covalent inorganic-organic hybrid framework with mesostructures is constructed by sur factantdirected polycondensation of bridged organosilane precursors (R[Si(OR′) 3 ] n ; n ≥ 2). Functionalization of meso structured organosilicas is achievable in various ways, such as tuning of the composition of the organosilica framework, chemical surface modification of the pore walls, and introduc tion of guest materials into the mesopores.…”

Post‐Synthetic Anisotropic Wet‐Chemical Etching of Colloidal Sodalite ZIF Crystals

“…[3,4] MOFs are built up from metal ions/clusters connected through organic linkers.T heir exposed crystal facets,e dges,a nd vertices can exhibit different chemical compositions.W ehypothesized that agents capable of breaking the coordination bonds between the metal ions/clusters and the organic linkers could be exploited to preferentially etch specific external crystal surfaces (with more density of coordination bonds) over others.W ee nvisioned that such control would enable us to post-synthetically tailor the shape of MOF crystals.T od ate,p ost-synthetic random etching of MOF crystals using H + ,N a + ,a nd quinone has already been demonstrated. [7,8] However, to date,n oo ne has demonstrated the ability to rationally and post-synthetically control the anisotropic etching of ap orous MOF crystal as ap roperty of its crystal planes,t oshape it into different morphologies.Isostructural ZIF-8 and ZIF-67 are among the most important porous MOF materials known today.T hey are isomorphous with zeolites,and their 3D frameworks,built up from connecting Zn II ions (ZIF-8) or Co II ions (ZIF-67) through 2-methylimidazole (2-MIM) linkers,s how as odalite topology featuring large cavities (11.6 ) and small apertures (3.4 ; Supporting Information, Figure S1). [7,8] However, to date,n oo ne has demonstrated the ability to rationally and post-synthetically control the anisotropic etching of ap orous MOF crystal as ap roperty of its crystal planes,t oshape it into different morphologies.…”

Post‐Synthetic Anisotropic Wet‐Chemical Etching of Colloidal Sodalite ZIF Crystals

“…[5,6] Inspired by similar results with zeolites, this strategy has enabled researchers to prepare hierarchical MOF crystals and/or create macropores on the MOF crystal surfaces. [7,8] However, to date, no one has demonstrated the ability to rationally and post-synthetically control the anisotropic etching of a porous MOF crystal in function of its crystal planes, to shape it into different morphologies.…”