The SPR-generated electric field (E-field) intensities around a Ag nanocube (NC) before and after covered by BaTiO3 (BTO) layer (BTO@Ag NC) were calculated. It was observed that the theoretical E-field intensities were reduced on BTO@Ag NC, thus suggesting inferior catalytic activities under visible light illumination. However, BTO@Ag NCs experimentally displayed better photocatalytic performance than that of Ag NCs under illumination at 633 nm, both in ambient argon (Ar) and in ambient air, where PATP molecules were used to probe the conversion. The mechanism can be attributed to the surface polarization of BTO layer trigged by SPR effect of Ag core. The oscillation of free electrons in Ag core aroused appearance of surface polarization charge on ferroelectric (FE) BTO surface, which resulted in the enhanced catalytic properties of BTO@Ag NCs. Therefore, our finding may provide a novel method to enhance visible-light responsive photocatalytic activity of wide bandgap FE materials by depositing them on plasmonic metal nanostructures.
Porous Core‐membrane Microstructured Nanomaterial Composed of Deep Eutectic Solvents and MOF‐808 for CO2 Capture
A kind of ionic liquid, namely deep eutectic solvents, are introduced to load on the surface of porous MOF-808 core as membranes to construct porous core-membrane microstructured nanomaterials for CO2 capture at room temperature with the sorption mechanism coupling of diffusion, physisorption, and chemisorption. It shows excellent development potential for future application in CO2 capture.
Abstract
A series of porous core-membrane microstructured nanomaterials, constructed of a deep eutectic solvent (DES) membrane and porous MOF-808 core via liquid surface tensions and electrostatic interactions, are introduced for carbon dioxide capture with the sorption mechanism coupling diffusion, physisorption, and chemisorption. MOF-808 as the porous core considerably improves the diffusion interactions for DES membranes, hence significantly enhancing the sorption performance of DESs. Although the DES consisted by monoethanolamine and tetrapropylammonium chloride (MEA-TPAC-7) has the highest sorption capacity among all DESs, it is only 4.39 mmol g−1 at 2.4 bar and further attenuates by fastidious diffusion interactions when increasing viscosity or dose. The sorption capacities of DES@MOF-120 are 5.18 mmol g−1 at 3.0 bar and 4.78 mmol g−1 at 2.4 bar without apparent sorption hysteresis in pressure swing sorption, which are substantially improved contrasted to MEA-TPAC-7. The sorption isotherms are reconstructed via Sips models considering surface heterogeneity with regression correlation coefficients over 0.9454 to forecast maximum sorption capacity over 6.33 mmol g−1.
Solid‐State Absorption, Luminescence, and Singlet Fission of Furanyl‐Substituted Diketopyrrolopyrroles with Different π‐Stacking Arrangements
Furanyl-substituted diketopyrrolopyrroles (DPP) with different branching of the alkyl side chains were studied. Both formed two distinct types of π-stacking leading to H-aggregates with considerably different energetics in terms of mixed lowest Frenkel and charge transfer (CT) states. The combined effect of the molecular structure and solid-state arrangement lead to fast and efficient CT mediated singlet fission, with one of the highest efficiencies (160 %) ever reported within the DPP family.
Abstract
Small modifications of the diketopyrrolopyrrole (DPP) molecular structure induced remarkable changes in its spectral and photophysical behavior. Using furan (F) heterosubstitution instead of thiophene (T) substituent resulted in a small blue shift and decreased Huang-Rhys factor of the absorption spectra in solution, irrespectively to N,N'-alkyls. Branching of alkyl side chains by formal 2-ethylation of n-hexyl substituent (C6 to EH) switched the slipped-stack arrangement, irrespectively on the heteroatoms. Consequent changes in steady-state absorption spectra of thin films were interpreted using time dependent density functional theory calculations, carried out on model dimers. Solid-state luminescence is weak and partially dependent on an excitation wavelength. Singlet fission was observed by femtosecond transient absorption spectroscopy, with considerably different yields for variously π-stacked FDPP-EH (30 %) and FDPP-C6 (160 %). The shape of triplet-triplet absorption spectra was also influenced by various π-stacking. The results are discussed in terms of different mixing of both Frenkel and charge transfer states in model dimers and different excitonic and electronic coupling in both types of π-stacks, visualized by natural transition orbitals.
Environmental Feasibility Analysis for the Acrylonitrile Production from Glycerol
The application of the life cycle assessment technique for the acrylonitrile production from glycerol is proposed with propylene or glycerol as the main feedstock to compare the results, aiming at evaluating the environmental impacts generated in the process. The glycerol-based process from two sources (soybean, waste cooking oil) demonstrated promise in reducing fossil fuels and water consumption.
Abstract
Acrylonitrile is a monomer traded as a commodity on the global market with applications in several industrial sectors, produced from the ammoxidation of propylene. New technological alternatives are being studied, reducing the use of petroleum derivatives through renewable raw materials. This article proposes the application of the life cycle assessment technique for acrylonitrile production from glycerol, with the objective of evaluating the environmental impacts generated in the process. The results demonstrated that the use of glycerol from the state of Mato Grosso can reduce consumption of fossil fuel and water by 45 % and 31 %, respectively. The results about greenhouse gas (GHG) emissions were little significant when replacing the raw material.
Biochar‐MgO from Soursop Seeds in Production of Biofuel Additive Intermediates.
The conversion of residual biomass from fruit seeds into biochar can be achieved using MgCl2 as an activating agent and calcining at 700 °C. The resulting MgO-biochars were employed in the aldol condensation reaction between furfural and acetone. This reaction is essential as the first step in the obtention of biofuels derived from biomass. The biochars were characterized through various physicochemical techniques, revealing that the presence of MgO nanoparticles deposited on the carbon surface modifies the structural and acidic-basic properties of the carbonaceous materials with a graphitic structure. The biochar with a surface content of MgO of 0.34% w/w enables the achievement of 100% of selectivity towards 4-(2-furanyl)-3-buten-2-one (I) with quantitative conversions under optimized conditions. This property highlights the potential of using this type of biochar, commonly used for CO2 capture, as a versatile acidic-basic catalyst, thereby introducing a novel approach to sustainable chemistry.
Preparation and characterization of bovine serum albumin nanoparticles conjugated with folic acid and loaded with PEGylated thymol and evaluation of their anticancer properties
Phenolic compounds such as thymol have an effective role in suppressing cancer, however, their low solubility in aqueous solution has limited their use. This study aimed to prepare thymol (TY)-loaded bovine serum albumin (BSA) nanoparticles surface-modified with polyethylene glycol (PEG) conjugated with folic acid (FA) and evaluate the inhibitory activity of them on cancer cells. The TY-BSA-PEG-FA was characterized using DLS, FESEM, and FTIR. The effects of nanoparticles against cancer cells investigated by MTT, AO/PI, flow cytometry, and qPCR methods. The results showed that the spherical morphology of TY-BSA-PEG-FA with an average size of 70.0 nm, a PDI of 0.32, a zeta potential of -11.3 mV, and an EE of 89%. Gastric cancer cells eported to be the most vulnerable to treatment, while pancreatic cancer cells and normal skin cells would be the most resistant. The SubG1 phase arrest and increase in apoptotic cells in fluorescent staining, along with decreased expression of Bcl-2 and increased expression of BAX gene demonstrated the induction of apoptosis in treated cells. The powerful inhibitory effect of nanoparticles in inhibiting ABTS (IC50=82µg/ml) and DPPH (IC50=844µg/ml), the synthesized nanoparticles may be suitable for further investigation in the treatment of cancer, notably gastric cancer.
Synthetic Applications of Photochemically Generated Radicals from Protic C(sp3)–H Bonds
The utilization of photo-induced processes in C–H functionalization via radical pathways has emerged as a highly promising strategy for the preparation and modification of complex organic compounds. While current methods for generating carbon-centred radicals from C–H bonds primarily focus on hydridic C–H bonds to yield nucleophilic radical species, the reactivity and potential applications of electrophilic radicals derived from protic C–H bonds remain largely unexplored. In this review, we aim to shed light on the seminal findings regarding the activation of protic C(sp3)–H bonds while also showcasing noteworthy examples of this radical formation process. Mechanistically diverse modes of activation are discussed, unified by proton-coupled electron transfer (PCET) concepts.
Synthesis of Functional Isosorbide‐Based Polyesters and Polyamides by Passerini Three‐Component Polymerization
A new family of functional isosorbide-based polyesters and polyamides with high glass transition temperature are prepared via Passerini-three component polymerization (P-3CP). To optimize the P-3CP conditions, the influence of the polymerization solvent, temperature, feed ratio on the molar mass of final polymers are investigated. The higher molar mass (up to 10100 g/mol) and yield (>70%) are achieved under mild conditions (30 °C, standard atmosphere). Functional side groups, such as alkenyl, alkynyl and methyl ester, were introduced into polymer structure via P-3CP by using functional isocyanides. The obtained polyesters and polyamides are characterized by nuclear magnetic resonance (NMR) and infrared (IR) spectroscopies, differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). All polymers are thermal stable and amorphous with variable glass transition temperatures (Tg). The obtained polyester has Tg up to 87.5 °C, while the Tg of polyamides (ISPA-2) is detected to be 97.5 °C depending on the amide bonds in the polymer backbone and the benzene ring side groups. The cytotoxicity is investigated by the CCK-8 assay against mBMSC cells to confirm the biological safety. Overall, this novel strategy provides an efficient approach to produce functional isosorbide-based polyesters and polyamides, which are promising prospect for being applied to biodegradable materials.
New protocol for the synthesis of S‐thioesters from benzylic, allylic and tertiary alcohols with thioacetic acid
A new one-pot solvent-less reaction to convert benzylic, allylic, ferrocenyl or tertiary alcohols into S-thioesters, bench-stable and less odorous precursors of the corresponding thiols, which is based on reactions in neat thioacetic acid in the presence of tetrafluoroboric acid, is presented. Reaction monitoring by NMR and GC of the benzyl alcohol conversion indicated the intermediate formation of benzyl acetate and benzyl thionoacetate (PhCH2OC(S)CH3) prior to the slower conversion to the final S-benzyl thioacetate product. Increasing the HBF4 concentration enhanced the reaction rate, giving good to excellent yield (up to 99%) for a large scope of alcohols. Control experiments, with support of DFT calculations, have revealed a thermodynamically favorable, though requiring HBF4-activation, disproportionation of CH3C(O)SH to CH3C(O)OH and CH3C(S)SH, the latter immediately decomposing to H2S and (MeC)4S6 but also generating the hitherto unreported [MeC(O)C(Me)S]2(µ-S)2. Kinetic investigations demonstrated that the rate of benzyl alcohol conversion is second-order in [PhCH2OH] and second order in [HBF4], while the rate of conversion of the benzyl acetate intermediate to S-benzyl thioacetate is second order in [PhCOOMe] and fourth order in [HBF4]. The DFT calculations rationalize the need to two alcohol molecules and two protons to generate the reactive benzyl cation.
[ASAP] Structure and Electrochemical Properties of Bronze Phase Materials Containing Two Transition Metals
Chemistry of Materials
DOI: 10.1021/acs.chemmater.3c01860