Ag NPs decorated on a COF in the presence of DBU as an efficient catalytic system for the synthesis of tetramic acids via CO2 fixation into propargylic amines at atmospheric pressure
Abstract:Ag NPs are decorated at the surface of a COF material TpPa-1 and the resulting Ag@TpPa-1 catalyzes efficiently for the synthesis of tetramic acids from a variety of propargylic amines using CO2 as reagent.
“…The highest catalytic activity of Ag. NPs could be attributed in terms of their maximum surface area7.38m 2 /g with total pore volume as 0.0389 mL/g and average pore radius as 1.0964 nm 61 . Figure 8 Nitrogen adsorption/desorption isotherms of Ag.…”
Silver nanoparticles (Ag. NPs) have shown a biological activity range, synthesized under different environment-friendly approaches. Ag. NPs were synthesized using aqueous crude extract (ACE) isolated from Plantago lanceolata. The ACE and Ag. NPs were characterized and assessed their biological and antioxidant activities. The existence of nanoparticles (NPs) was confirmed by color shift, atomic force microscopy (AFM), and UV–Vis’s spectroscopy. The FT-IR analysis indicated the association of biomolecules (phenolic acid and flavonoids) to reduce silver (Ag+) ions. The SEM study demonstrated a sphere-shaped and mean size in the range of 30 ± 4 nm. The EDX spectrum revealed that the Ag. NPs were composed of 54.87% Ag with 20 nm size as identified by SEM and TEM. AFM has ended up being exceptionally useful in deciding morphological elements and the distance across of Ag. NPs in the scope of 23–30 nm. The TEM image showed aggregations of NPs and physical interaction. Ag. NPs formation also confirmed by XPS, DRS and BET studies. Ag. NPs showed efficient activity as compared to ACE, and finally, the bacterial growth was impaired by biogenic NPs. The lethal dose (LD50) of Ag. NPs against Agrobacterium tumefaciens, Proteus vulgaris, Staphylococcus aureus, and Escherichia coli were 45.66%, 139.71%, 332.87%, and 45.54%, with IC50 (08.02 ± 0.68), (55.78 ± 1.01), (12.34 ± 1.35) and (11.68 ± 1.42) respectively, suppressing the growth as compared to ACE. The antioxidant capacity, i.e., 2,2-diphenyl-1-picrylhydrazyl (DPPH) of Ag. NPs were assayed. ACE and Ag. NPs achieved a peak antioxidant capacity of 62.43 ± 2.4 and 16.85 ± 0.4 μg mL−1, compared to standard (69.60 ± 1.1 at 100 μg mL−1) with IC50 (369.5 ± 13.42 and 159.5 ± 10.52 respectively). Finally, the Ag. NPs synthesized by P. lanceolata extract have an excellent source of bioactive natural products (NP). Outstanding antioxidant, antibacterial activities have been shown by NPs and can be used in various biological techniques in future research.
“…The highest catalytic activity of Ag. NPs could be attributed in terms of their maximum surface area7.38m 2 /g with total pore volume as 0.0389 mL/g and average pore radius as 1.0964 nm 61 . Figure 8 Nitrogen adsorption/desorption isotherms of Ag.…”
Silver nanoparticles (Ag. NPs) have shown a biological activity range, synthesized under different environment-friendly approaches. Ag. NPs were synthesized using aqueous crude extract (ACE) isolated from Plantago lanceolata. The ACE and Ag. NPs were characterized and assessed their biological and antioxidant activities. The existence of nanoparticles (NPs) was confirmed by color shift, atomic force microscopy (AFM), and UV–Vis’s spectroscopy. The FT-IR analysis indicated the association of biomolecules (phenolic acid and flavonoids) to reduce silver (Ag+) ions. The SEM study demonstrated a sphere-shaped and mean size in the range of 30 ± 4 nm. The EDX spectrum revealed that the Ag. NPs were composed of 54.87% Ag with 20 nm size as identified by SEM and TEM. AFM has ended up being exceptionally useful in deciding morphological elements and the distance across of Ag. NPs in the scope of 23–30 nm. The TEM image showed aggregations of NPs and physical interaction. Ag. NPs formation also confirmed by XPS, DRS and BET studies. Ag. NPs showed efficient activity as compared to ACE, and finally, the bacterial growth was impaired by biogenic NPs. The lethal dose (LD50) of Ag. NPs against Agrobacterium tumefaciens, Proteus vulgaris, Staphylococcus aureus, and Escherichia coli were 45.66%, 139.71%, 332.87%, and 45.54%, with IC50 (08.02 ± 0.68), (55.78 ± 1.01), (12.34 ± 1.35) and (11.68 ± 1.42) respectively, suppressing the growth as compared to ACE. The antioxidant capacity, i.e., 2,2-diphenyl-1-picrylhydrazyl (DPPH) of Ag. NPs were assayed. ACE and Ag. NPs achieved a peak antioxidant capacity of 62.43 ± 2.4 and 16.85 ± 0.4 μg mL−1, compared to standard (69.60 ± 1.1 at 100 μg mL−1) with IC50 (369.5 ± 13.42 and 159.5 ± 10.52 respectively). Finally, the Ag. NPs synthesized by P. lanceolata extract have an excellent source of bioactive natural products (NP). Outstanding antioxidant, antibacterial activities have been shown by NPs and can be used in various biological techniques in future research.
“…The fact that the conversion does not transpire in the absence of the COF confirms that the COF plays a key role in trapping and activating the CO 2 molecules. There are few reports on CO 2 conversion using COF where epoxides and propargyl amines are being used as the reagent for chemical fixation . But, to the best of our knowledge, this is the first report of COF based heterogeneous catalyst to convert CO 2 into α‐alkylidene cyclic carbonates using propargyl alcohols with high selectivity and yields.…”
Covalento rganic frameworks are an ew class of crystalline organic polymers possessing ah igh surfacea rea and ordered pores. Judicious selection of buildingb locks leads to strategic heteroatom inclusion into the COF structure. Owing to their high surfacea rea, exceptional stability and molecular tunability,C OFs are adopted for various potential applications. The heteroatoms lining in the pores of COF favor synergistich ost-guest interaction to enhance a targeted property.I nt his report, we have synthesized ar esorcinol-phenylenediamine-based COF which selectively adsorbs CO 2 into its micropores (12 ). The heat of adsorption value (32 kJ mol À1 )o btainedf rom the virial model at zero-loading of CO 2 indicates its favorable interaction with the framework. Furthermore, we have anchored small-sized Ag nanoparticles ( % 4-5 nm) on the COF and used the composite for chemicalf ixationo fC O 2 to alkylidenec yclic carbonates by reacting with propargyl alcohols under ambient conditions. Ag@COFc atalyzes the reaction selectively with an excellent yield of 90 %. Recyclability of the catalyst has been demonstrated up to five consecutivec ycles. The postcatalysis characterizations revealt he integrity of the catalyst even after fiver eaction cycles.T his study emphasizes the ability of COF for simultaneous adsorption and chemical fixation of CO 2 into corresponding cyclic carbonates.
“…Meanwhile, the characteristic diffraction peaks of Ag NPs at 37.7, 44.0, and 64.1 correspondingly belonging to the (111), (202), and (220) facets were clearly observed in Ag@DhaTph-COOH. 77 The N 2 adsorption isotherm of Ag@DhaTph-COOH indicated that its N 2 adsorption capacity and BET surface area decreased to 224.6 cm 3 g À1 and 259.3 m 2 g À1 , respectively (Fig. 1c), which was undoubtedly caused by the partial pore occupation of Ag NPs.…”
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