A series of highly thermally and hydrolytically stable porous solids with intriguing properties of zirconium- and hafnium-based metal–organic frameworks (MOFs) [Dresden University of Technology (DUT) series] was synthesized. The DUT MOFs were found to be effective catalysts for both epoxide–CO2 cycloaddition reactions and the catalytic transfer hydrogenation (CTH) of ethyl levulinate (EL). In particular, 12-connected DUT-52­(Zr) showed higher catalytic activity than eight- and six-connected catalysts in the synthesis of cyclic carbonates as well as in the production of γ-valerolactone (GVL). The secondary building unit connectivity, coexistence of a moderate number of acidic and basic sites, Brunauer–Emmett–Teller surface area, and combined effects of the pores of the MOFs seem to influence the catalytic activity. The reaction mechanism for the DUT-52­(Zr)-mediated cycloaddition reaction of CO2 and the CTH reactions were investigated in detail by using periodic density functional theory calculations. To the best of our knowledge, this is the first detailed computational study for the formation of GVL from EL by using MOF as the catalyst. In addition, grand canonical Monte Carlo simulations predicted the strong interaction of CO2 molecules with the DUT-52­(Zr) framework. Remarkably, the DUT-series catalysts possess extraordinary tolerance toward water. Further, DUT-52­(Zr) is recyclable and is an efficient catalyst for cycloaddition and CTH reactions for at least five uses without obvious reductions in the activity or structural integrity.

Acute detection of assorted classes of organo-toxins in a practical environment is an important sustainable agenda, whereas cooperative and recyclable catalysis can mitigate hazards by minimizing energy requirements and reducing waste generation. We constructed an acid-/base-stable Co(II)-framework with a unique network topology, wherein unidirectional porous channels are decorated by anionic [Co 2 (μ 2 -OH)(COO) 4 (H 2 O) 3 ] secondary building units and neutral [CoN 2 (COO) 2 ] nodes. An intense luminescent signature of the hydrolytically robust framework is harnessed for the selective, fast-responsive, and regenerable detection of two detrimental organo-aromatics, 4-aminophenol (4-AP) and 2,4,6-trinitrophenol (TNP). Alongside remarkable quenching, their nanomolar detection limits (4-AP: 99.5 nM; TNP: 67.2 nM) rank among the lowest reported values in water and corroborate their ultra-sensitivity. Density functional theory (DFT) calculations verify the electron-transfer route of sensing through portraying redistribution of energy levels of molecular orbitals in a threedimensional network by each analyte and further envisages non-covalent host−guest interactions. Benefiting from the concurrent existence of an open-metal site and a triphenylamine-moiety-functionalized ligand, the activated framework acts as an outstandingly cooperative heterogeneous catalyst in deacetalization−Knoevenagel condensation under mild conditions. The acid−base dual catalysis is detailed for the first time from combined inputs of control experiments and DFT validations. To the best of tandem reaction, larger-sized substrate exhibits insignificant conversion, and certifies rarest pore-fitting induced size-selectivity.

The capture and conversion of CO2 from direct air into value-added products under mild conditions represents a promising step towards environmental remediation and energy sustainability. Consequently, herein, we report application...

Metal-organic frameworks (MOFs) have surfaced as incipient class of multifaceted materials for selective carbon dioxide (CO2) adsorption and luminescent detection of assorted classes of lethal organo-aromatics, where functional group assisted...

The CO 2 capture capability of ultra-microporous pillared square grid fluorinated metal−organic framework (MOF), i.e., [(M′F 6 )M(L) 2 ] n , (where M′, M, and L are pillared metal ion, divalent cation, and ligand, respectively), is exercised with a combined advanced density functional theory (DFT) and grand canonical Monte Carlo (GCMC)-based simulation through tuning of its structural skeleton by several possible metal ions and various ligands. As an initial step, M′FSIX-Ni-pyr MOF series were made by altering various metal ions possessing octahedral coordination in M′F 6 moieties (M′ = Si, Ga, Zr, Ge, Sn, Ti, V, and Nb) but keeping nickel and pyrazine as divalent cation (M = Ni) and ligand, respectively. M′FSIX-Ni-pyr MOF series were considered based on the prototype [(M′F 6 )Ni(1,4-pyrazine) 2 ] n porous structure having ultra-micropore size as 4.0 Å (when M′ = Si, the MOF is denoted as SIFSIX-Ni-pyr). The replacement of pillared metal ion possessing octahedral coordination in M′F 6 moieties does not provide any significance in CO 2 adsorption capability than the parent structure, SIFSIX-Ni-pyr. Further, we adopted another criterion for tuning the structural dimension in [(M′F 6 )Ni(L) 2 ] n by choosing various ligands (L) such as 4,4′-bipyridine (byp), 4,4′-azopyridine (apy), 4,4′-bipyridylacetylene (bpa), and 3,-di(4-pyridyl)-1,2,4,5tetrazine (dpt), i.e., SIFSIX-Ni-L MOF series. Coadsorption studies of CO 2 and N 2 with molar compositions of 15 and 85%, respectively, reveal that the CO 2 /N 2 selectivity decreased drastically on increasing the length of ligands, even though the adsorption capacity is much better than SIFSIX-Ni-pyr. However, for keeping better selectivity without compromising the adsorption capacity, a double-folded interpenetration is carried out in all SIFSIX-Ni-L MOFs to generate another SIFSIX-Ni-L-i MOF series. Eventually, SIFSIX-Ni-L-i MOF series showed better adsorption capacity toward CO 2 without compromising the optimal selectivity, which is validated by pore size distribution (PSD), working capacity (WC), and adsorption performance indicator (API). Among the three possibilities of changing the structural configuration of M′FSIX-Ni-L, [(M′F 6 )M(L) 2 ] n , fluorinated MOFs such as pillared metal-ion variants, length of ligand, and its structural interpenetration, the last one stands out for CO 2 capture performance. From screening of entire fluorinated MOFs, both SIFSIX-Ni-bpa-i and SIFSIX-Ni-dpt-i showed better CO 2 capture performance from industrial flue gas composition, which suggested that the optimal adsorbent should possess a threshold pore size, i.e., 4.0−4.5 Å, with better CO 2 adsorption sites in the pore wall.