02313nas a2200241   4500008004100000022001400041245012600055210006900181260000800250520143000258653001601688653003201704653002201736653002301758653002501781100002601806700002201832700002201854700002001876700001801896700003001914856012701944       2019                        eng d  a1861-472800aAg nanoparticles supported on a resorcinol-phenylenediamine-based covalent organic framework for chemical fixation of CO20 aAg nanoparticles supported on a resorcinolphenylenediaminebased   cOCT3 a<p>Covalent organic frameworks are a new class of crystalline organic polymers possessing a high surface area and ordered pores. Judicious selection of building blocks leads to strategic heteroatom inclusion into the COF structure. Owing to their high surface area, exceptional stability and molecular tunability, COFs are adopted for various potential applications. The heteroatoms lining in the pores of COF favor synergistic host-guest interaction to enhance a targeted property. In this report, we have synthesized a resorcinol-phenylenediamine-based COF which selectively adsorbs CO2 into its micropores (12 angstrom). The heat of adsorption value (32 kJ mol(-1)) obtained from the virial model at zero-loading of CO2 indicates its favorable interaction with the framework. Furthermore, we have anchored small-sized Ag nanoparticles (approximate to 4-5 nm) on the COF and used the composite for chemical fixation of CO2 to alkylidene cyclic carbonates by reacting with propargyl alcohols under ambient conditions. Ag@COF catalyzes the reaction selectively with an excellent yield of 90 %. Recyclability of the catalyst has been demonstrated up to five consecutive cycles. The post-catalysis characterizations reveal the integrity of the catalyst even after five reaction cycles. This study emphasizes the ability of COF for simultaneous adsorption and chemical fixation of CO2 into corresponding cyclic carbonates.</p>
10aCO2 capture10acovalent organic frameworks10acyclic carbonates10aPropargyl alcohols10asilver nanoparticles1 aChakraborty, Debanjan1 aShekhar, Pragalbh1 aSingh, Himan, Dev1 aKushwaha, Rinku1 aVinod, C., P.1 aVaidhyanathan, Ramanathan  uhttps://library.ncl.res.in/content/ag-nanoparticles-supported-resorcinol-phenylenediamine-based-covalent-organic-framework02165nas a2200253   4500008004100000022001400041245008400055210006900139260000800208300001500216490000700231520135000238653001601588653001701604653001101621653001701632100002201649700002201671700002601693700002101719700002801740700003001768856011301798       2022                        eng d  a1861-472800aCoordination flexibility aided CO2-specific gating in an iron isonicotinate MOF0 aCoordination flexibility aided CO2specific gating in an iron iso  cFEB  ae2021013050 v173 a<p>
	Coordination flexibility assisted porosity has been introduced into an Iron-isonicotinate metal-organic framework (MOF), (Fe(4-PyC)(2) . (OH). The framework showed CO2-specific gate opening behavior, which gets tuned as a function of temperature and pressure. The MOF ` s physisorptive porosity towards CO2, CH4, and N-2 was investigated; it adsorbed only CO2 via a gate opening phenomenon. The isonicotinate, representing a borderline soft base, is bound to the hard Fe3+ centre through monodentate carboxylate and pyridyl nitrogen. This moderately weak binding enables isonicotinate to spin like a spindle under the CO2 pressure opening the gate for a sharp increase in CO2 uptake at 333 mmHg (At 298 K, the CO2 uptake increases from 0.70 to 1.57 mmol/g). We investigated the MOF ` s potential for CO2/N-2 and CO2/CH4 gas separation aided by this gating. IAST model reveals that the CO2/N-2 selectivity jumps from 325 to 3131 when the gate opens, while the CO2/CH4 selectivity increases three times. Interestingly, this Fe-isonicotinate MOF did not follow the trend set by our earlier reported Hard-Soft Gate Control (established for isostructural M2+-isonicotinate MOFs (M=Mg, Mn)). However, we account for this discrepancy using the different oxidation state of metals confirmed by X-ray photoelectron spectroscopy and magnetism.</p>
10aCO2 capture10aflexible MOF10agating10aIsonicotinic1 aSingh, Himan, Dev1 aNandi, Shyamapada1 aChakraborty, Debanjan1 aSingh, Kirandeep1 aVinod, Chathakudath, P.1 aVaidhyanathan, Ramanathan  uhttps://library.ncl.res.in/content/coordination-flexibility-aided-co2-specific-gating-iron-isonicotinate-mof