RESUMEN

A set of unique triptycene-based and organic Schiff-base-linked polymers (TBOSBLs) are conveniently synthesized in which triptycene motifs are connected with 1,3,5-triformylphloroglucinol units via Schiff-base linkages. TBOSBLs are amorphous, thermally stable with a reasonable surface area (SABET up to 649 m2/g), and have abundant nanopores (pore size < 100 nm). TBOSBLs are good sorbents for small gas molecules (such as CO2, H2, and N2) and they can selectively capture CO2 over N2. Additionally, TBOSBLs show superior antiproliferative activity against human colorectal cancer cells relative to previously reported covalent organic frameworks (COFs). The mechanism of cell death is also studied elaborately.

RESUMEN

Sustainable energy is the most valuable clean and renewable energy for the future. A simple, robust, and inexpensive ecofriendly method has been developed here to prepare chitosan-based zeolite porous biocomposites via solvent exchange followed by calcination. The resulting chitosan-based zeolite biocomposites were characterized using advanced technologies including attenuated total reflection-infrared (ATR-IR) spectroscopy, X-ray powder diffraction (XRD) analysis, thermogravimetric analysis (TGA), high-resolution field-emission scanning electron microscopy (HR-FE-SEM), high-resolution transmission electron microscopy (HR-TEM), and nitrogen adsorption-desorption isotherms. The Brunauer-Emmett-Teller (BET) surface area of the ZeY@CS composite (795 m2 g-1) was greater than those of ZSM-5@CS (444 m2 g-1), pure chitosan, pure zeolite Y, and ZSM-5. The chitosan-based zeolite biocomposites show enhanced gas storage for small molecule like CO2 and hydrogen. Therefore, chitosan-based zeolite biocomposites should be suitable for energy storage, carbon capture, and sequestration (CCS) applications.

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RESUMEN

Two new triptycene-based azobenzene-functionalized polymers (TBAFPs) have been synthesized using the well-known Pd-catalyzed Sonogashira cross-coupling polycondensation reaction between 2,6-diethynyltriptycene and (meta or para) dibromo-azobenzenes. Enhancement of the fluorescent emission intensity was observed upon trans → cis isomerization of -N=N- linkage in TBAFPs. The cis-lifetime of TBAFP1 is rather long (greater than 2 days). The resulting materials were tested as a potential chemosensor for the detection of picric acid (PA)-a water pollutant as well as chemical constituent of explosives used in warfare. PA was found to interact strongly with TBAFPs, which led to significant quenching of the latter's fluorescence emission intensities. The binding constants are in the order of 105 M-1. TBAFPs were also able to detect PA in nanomolar concentrations.

RESUMEN

We have demonstrated a superficial, environmentally friendly and sustainable development of chitosan (CS) grafted graphene oxide aerogels for adsorption of CO2 gas. The CS is grafted into the carbonaceous materials like graphene oxide, multi-walled carbon nanotubes etc. to provide the large surface area, high porosity and a large number of amine group which facilitates the adsorption of CO2 gas. CS and carbonaceous materials undergo crosslinking by using cross-linker reagents, and freeze-drying technique to yield CS based aerogels with ordered porous structures. Crosslinking between CS and carbonaceous materials was confirmed by FT-IR. Physical properties of the CS-based aerogels were studied using SEM, TGA, XRD, BET isotherm analysis. The adsorption capacity of CO2 gas by CS grafted graphene oxide aerogels is around 0.257 mmol g-1 at 1 bar, that is significantly higher in comparison to the adsorption capacity of pure CS. We believe that this study helps to reduce the cost of adsorbents due to the large availability of marine waste (CS) and thus aims to reduce the anthropogenic CO2 gas at low cost, favourable temperature and pressure as compared to previously reported.

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RESUMEN

The quantitative, single step, self-assembly of a shape-persistent, three-dimensional C3v-symmetric, triptycene-based tris-terpyridinyl ligand initially gives a platonic-based cubic architecture, which was unequivocally characterized by 1D and 2D NMR spectroscopy, mass spectrometry, and single crystal X-ray structural analysis. The unique metal-ligand binding properties of the Cd2+ analogue of this construct give rise to a concentration-dependent dynamic equilibrium between cube, prism, and tetrahedron-shaped architectures. Dilution transforms this cube into two identical tetrahedra through a stable prism-shaped intermediate; increasing the concentration reverses the process.