Fabrication of Hybrid Organic-Inorganic Materials with Tunable Porosity for Catalytic Application

Organoamine Templated Multifunctional Hybrid Metal Phosphonate Frameworks: Promising Candidates for Tailoring Electrochemical Behaviors and Size-Selective Efficient Heterogeneous Lewis Acid Catalysis

The successful discovery of novel multifunctional metal phosphonate framework materials that incorporate newer organoamines and their utilization as a potential electroactive material for energy storage applications (supercapacitors) and as efficient heterogeneous catalysts are the most enduring challenges at present. From this perspective, herein, four new inorganic-organic hybrid zinc organodiphosphonate materials, namely, [C₅H₁₄N₂]₂[Zn₆(hedp)₄] (I), [C₅H₁₄N₂]_0.5[Zn₃(Hhedp) (hedp)]·2H₂O (II), [C₆H₁₆N₂][Zn₃(hedp)₂] (III), and [C₁₀H₂₄N₄][Zn₆(Hhedp)₂(hedp)₂] (IV) (H₄hedp = 1-hydroxyethane 1,1-diphosphonic acid), have been synthesized through the introduction of different organoamines and then structurally analyzed using various techniques. The compounds (I-IV) possess a three-dimensional network through alternate connectivity of zinc ions and diphosphonate ligands, as confirmed using single-crystal X-ray diffraction. The investigations of electrochemical charge storage behaviors of the present compounds indicate that compound III exhibits a high specific capacitance of 190 F g^-1 (76 C g^-1) at 1 A g^-1, while compound II shows an excellent cycling stability of 90.11% even after 5000 cycles at 5 A g^-1 in the 6 M KOH solution. Further, the present materials have also been utilized as active heterogeneous Lewis acid catalysts in the ketalization reaction. The screening of various substrate scopes during the catalytic process confirms the size-selective heterogeneous catalytic nature of the framework compounds. To our utmost knowledge, such a size-selective heterogeneous Lewis acid catalytic behavior has been observed for the first time in the amine templated inorganic-organic hybrid framework family. Moreover, the excellent size-selective catalytic efficiencies with the d¹⁰ metal system and recyclability performances make the compounds (I-IV) more efficient and promising Lewis acid heterogeneous catalysts.

Zeolite-derived hybrid materials with adjustable organic pillars

Porous organic-inorganic materials with tunable textural characteristics were synthesized using the top-down process by intercalating silsesquioxanes and polyhedral oligomeric siloxanes of different types between crystalline zeolite-derived layers. The influence of key parameters such as (i) linker nature (pure hydrocarbon, S-, N-containing); (ii) chain length in alkyl- and aryl bis(trialkoxysilyl) derivatives; (iii) denticity of the organic precursor molecules; (iv) nature and size of side chain in mono(trialkoxysilyl) substrates; (v) rigidity of the chain (saturated vs. unsaturated, aliphatic vs. aromatic); (vi) nature and size of leaving group on the structural and textural properties of formed hybrids was carefully addressed. It was established, that the optimal silsesquioxane appropriate for the formation of zeolite-derived hybrids with high textural characteristics should possess short alkyl or long aryl chains, relatively small leaving groups and denticity larger than 3. Addition of polydentate low-molecular binder improved the structural and textural characteristics of hybrids, especially when using bulky or hydrophilic linkers.

Impact of pore topology and crystal thickness of nanosponge zeolites on the hydroconversion of ethylbenzene

Gas-phase hydroconversion of ethylbenzene was investigated using *MRE, MFI and MTW-type zeolite nanosponges with a hydrogenating component (Pt/Al₂O₃). Spacious channel interconnections in MFI was concluded to remarkably impact product selectivity compared to *MRE and MTW.