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In continuation of previously reported results, the ionic liquid 1,5-diazabicyclo[4.3.0]non-5-ene-1-ium acetate was also found to be a powerful non-derivatizing solvent for cellulosic waste such as paper and cardboard. The ionic liquid could dissolve all the present bio-polymers (cellulose, hemicellulose, and lignin) in high concentrations, resulting in solutions with visco-elastic properties that were suitable for dry-jet wet fiber spinning. The cellulosic raw materials were refined gradually to identify the influence of residual components on the spinnability of the respective solution. Polymer degradation and losses in the spinning process could be avoided nearly entirely. With the exception of virtually unrefined cardboard, all the samples showed excellent spinnability, resulting in fibers with high tensile strength. Prototype textiles were produced to validate the quality of the fibers and demonstrate the possibility of using residual lignin in cardboard as a natural dye. [ABSTRACT FROM AUTHOR]

Ruthenium nitrosyl (RuNO) complexes continue to attract significant research interest due to several appealing features that make these photoactivatable nitric oxide (NO˙) donors attractive for applications in photoactivated chemotherapy. Interesting examples of molecular candidates capable of delivering cytotoxic concentrations of NO˙ in aqueous media have been discussed. Nevertheless, the question of whether most of these highly polar and relatively large molecules are efficiently incorporated by cells remains largely unanswered. In this paper, we present the synthesis and the chemical, photophysical and photochemical characterization of RuNO complexes functionalized with 17α-ethinylestradiol (EE), a semisynthetic steroidal hormone intended to act as a molecular Trojan horse for the targeted delivery of RuNO complexes. The discussion is centered around two main molecular targets, one containing EE (EE-Phtpy-RuNO) and a reference compound lacking this biological recognition fragment (Phtpy-RuNO). While both complexes displayed similar optical absorption profiles and NO˙ release efficiencies in aqueous media, important differences were found regarding their cellular uptake towards dermal fibroblasts, with EE-Phtpy-RuNO gratifyingly displaying a remarkable 10-fold increase in cellular uptake when compared to Phtpy-RuNO, thus demonstrating the potential drug-targeting capabilities of this biomimetic steroidal conjugate. [ABSTRACT FROM AUTHOR]

In view of the growing demand for synthetic molecules or materials by researchers from both the core sciences and interdisciplinary sectors, the field of organic synthesis needs to be strategically more powerful to produce more molecules in a shorter time. Ensuring a reduction in the use of solvents, catalysts, reagents, time, effort, and waste is essential during green chemical syntheses. Keeping those criteria in mind, the integration of chemical reactions is very much needed. Integrated organic synthesis can be considered the ideal replacement for stepwise synthesis to fulfill demand while maintaining green parameters. The electrochemical cascade process satisfies the essential criteria of greener integrated synthesis to a great extent, providing a modern strategic tool in the arsenal of synthetic chemists. The strategy is applied extensively by researchers, as evidenced by the growing number of publications, amounting to more than a hundred papers on the development of synthesis methods using electrochemical cascade reactions. A thorough understanding of the process is needed to implement the strategy further in targeted synthesis and methodology development for cutting-edge research. To grow the concept among researchers, a concise account of published articles on the topic, depicting the mechanisms, prospects, and problems of the developed methods, is highly desirable. Quenching the thirst herein, we present a concise review of electrochemical cascade processes reported in the literature since 2015. The precedent reactions developed earlier are also discussed in this context. Electrochemical multicomponent reactions involving the cascade process are also covered, expanding the scope of the review. The sections are classified based on the types of functionalization. The mechanistic details of each category of reactions are thoroughly covered to present a clear idea of the redox behavior of different reagents under electrochemical conditions. The prospects and problems associated with the methods are also discussed. [ABSTRACT FROM AUTHOR]

Two new mechanofluorochromic-active AIE non-planar phenothiazine-based dyes (E)-N′-((10-ethyl-10H-phenothiazin-3-yl)methylene)-4-methylbenzenesulfonohydrazide (EPMMBS) and (E)-N′-((10-ethyl-10H-phenothiazin-3-yl)methylene)benzenesulfonohydrazide (EPMBS), were designed and successfully fabricated using a simple one step aldimine condensation reaction strategy. The synthesized compounds EPMBS and EPMMBS with subtly different electron-withdrawing moieties, have distinct mechanofluorochromic phenomenon via fluorescence color and emission intensity changes upon mechanical grinding. The mechanofluorochromism was supported by PXRD (powder X-ray diffraction) and FESEM (field emission scanning electron microscopy) which highlighted the phase transition between the well-organized crystalline and the amorphous phase. Our work could provide a promising way to design more mechanofluorochromic materials. [ABSTRACT FROM AUTHOR]

Sequential peptide coupling plays a central role in chemical protein synthesis. This paper describes a new peptide derivative, peptide-aminothiazoline (At), whereof the C-terminus is functionalized with 2-aminothiazoline. Peptide-At streamlined the sequential peptide ligation in a one-pot manner and demonstrated the convergent synthesis of a circular protein and homogeneous glycoproteins. [ABSTRACT FROM AUTHOR]

Spin-crossover complexes, valued for their bistability, are extensively studied due to their numerous potential applications. A primary challenge in this molecular class is to identify effective methods to adjust the spin-transition temperature, which frequently falls outside the desired temperature range. This typically necessitates intricate chemical design and synthesis or the use of stimuli such as light or pressure, each introducing its own set of challenges for integrating these molecules into end-user applications. In this work, we aim to address this challenge using an oriented external electric field (OEEF) as one stimulus to modulate the spin-transition temperatures. For this purpose, we have employed both periodic and non-periodic calculations on three well-characterised Fe(II) SCO complexes, namely [Fe(phen)2(NCS)2] (1, phen = 1,10-phenanthroline), [Fe(bt)2(NCS)2] (2, bt = 2,2'-bi-2-thiazoline) and [Fe(py)2phen(NCS)2] (3, py = pyridine) possessing a similar structural motif of {FeN4N'2}. To begin with, DFT calculations employing the TPSSh functional were performed on complexes 1 to 3, and the estimated low-spin (LS) and high-spin (HS) gaps are 24.6, 15.3 and 15.4 kJ mol-1, and these are in the range expected for Fe(II) SCO complexes. In the next step, an OEEF was applied in the molecule along the pseudo-C2 axis that bisects two coordinated -NCS groups. Application of an OEEF was found to increase the Fe-ligand bond length and found to affect the spin-transition at the particular applied OEEF. While the HS state of 1 becomes the ground state at an applied field of 0.514 V Å-1, the LS state lies at a higher energy of 1.3 kJ mol-1. Similarly, complexes 2 and 3 also show the HS ground state at an applied field of 0.514 V Å-1, where the LS state stays at higher energies of 6.13 and 11.62 kJ mol-1, respectively. It is found that the overall change in enthalpy (HHL) and entropy (SHL) for the spin transition in the presence of OEEFs decreases upon increasing the strength of the applied field. The computed spin-transition temperature (T1/2) using DFT was found to be in close agreement with the experimentally reported values. It is estimated that on increasing the strength of the applied electric field, the T1/2 increases significantly. While the DFT computed T1/2 values for the optimised geometry of 1, 2 and 3 were found to be 134.6 K, 159.9 K and 111.4 K respectively, at the applied field of 0.6425 V Å-1 T1/2 increases up to 187.3 K, 211.0 K and 184.4 K respectively, unveiling an hitherto unknown strategy to tune the T1/2 values. A limited benchmarking was performed with five additional exchange-correlation functionals: PBE, BLYP, B3LYP*, B3LYP, and PBE0. These functionals were found to be unsuitable for predicting the correct SCO behaviour for complex 2, and their behaviour under various electric fields did not improve. This emphasises the importance of choosing the correct functional at zero OEEF prior to testing them under various electric fields. Furthermore, calculations were performed with complex 1 adsorbed on the Au(111) surface. The formation of an Au-S bond during adsorption significantly stabilises the low-spin (LS) state, hindering the observation of spin-crossover (SCO) behaviour. Nonetheless, the application of an OEEF reduces this gap and brings the T1/2 value closer to the desired temperature. This offers a novel postfabrication strategy for attaining SCO properties at the interface. [ABSTRACT FROM AUTHOR]

We report hereby a sensitive and rapid label free colorimetric assay of two amino acids, viz. L -arginine (L -Arg) and L -cysteine (L -Cys), through silver sol synthesized via a wet chemical method using 2-boronobenzoic acid (2- BBA) as a reducing and capping reagent in an aqueous alkaline medium. 2-BBA was synthesized in situ by the reaction of 2-formylphenylboronic acid (2-FBPA) and silver nitrate through Tollen's method. The as-synthesized silver sol exhibited the formation of nanocubes having their most predominant size in the range of 20–25 nm upon their TEM scanning and exhibiting an SPR band at 401 nm in their UV-vis spectrum. The same were further characterized by SEM, EDX, AFM, FTIR, XPS, DLS, and zeta potential measurements also. Separate interaction of the two amino acids, viz., L -Arg and L -Cys, with diluted AgNCs (1 : 2; AgNCs and Millipore water V/V) exhibited two different colors, pinkish grey and blue, respectively accompanied by distinctive shifts in their surface plasmon resonance (SPR) band also. The detection limits were found to be 6 μM and 3 μM for L -Arg and L -Cys respectively. Furthermore, L -Arg and L -Cys were quantified in a pharmaceutical sample each with their respective recovery rates of 99.2% and 90.1%. These AgNCs exhibited rich SERS characteristics also by intensifying the Raman peaks of L -Arg and L -Cys. Only a few one-pot aqueous chemical syntheses of silver nanocubes have been reported previously. Most probably, this is the third report of its kind. To the best of our knowledge, no silver nanoprobe exhibiting simultaneous detection of L -Arg and L -Cys has been reported to date. [ABSTRACT FROM AUTHOR]

The demand for fermentation-based chemicals is expected to grow in the coming years because of the increasing emphasis on using bio-based chemicals over petrochemicals. Growing crude oil prices and rising concerns about carbon discharge are the main reasons pushing the shift toward bio-based chemicals. 2,3-Pentanedione is one such high-value fine chemical that is currently produced in smaller quantities through a multi-stage chemical synthesis or extracted from milk waste. Here we report a green route to produce 2,3–pentanedione directly from vapour-phase condensation of crude lactic acid over polymorphic ZrO2. The catalyst exhibits high selectivity, activity and stability for the direct condensation of raw lactic acid to 2,3-pentanedione and achieved 99.7% LA conversion and 95.5% selectivity at 325 °C. [ABSTRACT FROM AUTHOR]

In recent years, mechanochemistry has become recognized as an efficient, practical, and sustainable alternative for chemical synthesis. Adhering to the principles of green chemistry, mechanochemistry enables solvent-free, faster, and energy-efficient reactions, thereby reducing waste production and enhancing atom economy. Herein, we present a new nickel-catalyzed mechanochemical High Throughput Experimentation (HTE) amination protocol enabled by Resonant Acoustic Mixing (RAM). The developed C–N cross-coupling reactions avoid possible contamination, scaling-up challenges, and parallel reaction limitations by applying an accelerated screening and optimization protocol. The reduced amount of solvents in the reactions and the minimal amount of reagents required highlight the advantages of our approach over most common solvent-based reactions, aligning with the principles of sustainability and resource efficiency. Furthermore, the mechanochemistry methodology demonstrates seamless scalability to a multigram scale without additional optimizations, emphasizing its potential for streamlined, environmentally friendly, and large-scale industrial production. [ABSTRACT FROM AUTHOR]

This study investigated the oxidation of 5-hydroxymethylfurfural (HMF) to produce valuable products such as 2,5-furandicarboxaldehyde (DFF), 5-formyl-2-furancarboxylic acid (FFCA) and 2,5-furandicarboxylic acid (FDCA) through (photo) chemical and enzymatic catalysis. Laccases from different sources, including Aspergillus spp., Pseudomonas cepacea, and Trametes versicolor, were evaluated for their catalytic activity in the HMF oxidation. Laccase from Trametes versicolor (LacTV) emerged as the most effective catalyst, achieving complete conversion of HMF under specific pH conditions. The reaction mechanisms were explored, revealing a preference for the primary alcohol oxidation pathway over the aldehyde, leading to the formation of DFF and subsequent conversion to FFCA and FDCA. The impact of substrate concentration on HMF conversion was examined, revealing optimal conversion at lower HMF concentrations (<100 mM) and reduced performance at higher concentrations (>100 mM). The study also examined the influence of blue light (430 nm) on this reaction, revealing the dependence on light exposure for gC3N4 based catalysts and a negative effect for LacTV. Furthermore, the study introduces a modular flow chemical platform that utilizes Continuous Stirred Tank Reactors (CSTR) in a cascade configuration, the optimization of HMF oxidation. The implementation of this innovative approach has led to the effective synthesis of FDCA, demonstrating an impressive 40-fold increase in productivity compared to the traditional batch system. These results present significant potential for advancing green chemistry and sustainable chemical synthesis, introducing novel possibilities for environmentally friendly HMF oxidation processes. [ABSTRACT FROM AUTHOR]

The photochemical, photophysical, and electrochemical properties of BODIPY compounds (1–7) substituted with iodine or pyrene at the 2-, 6-, or 8-positions (meso) were thoroughly investigated in this study. Through the incorporation of iodine and/or pyrene moieties into the BODIPY derivatives, we evaluated their impact on the photophysical properties using both steady-state and time-resolved fluorescence analyses. Notably, the heavy atom effect induced by iodine was observed, leading to an increase in singlet oxygen quantum yield in proportion to fluorescence intensity. Furthermore, the introduction of pyrene at the meso position in BODIPY (compound 5) significantly enhanced the π-conjugated system and facilitated the generation of singlet oxygen. Intriguingly, compound 7, which featured pyrene substitutions at positions 2, 6, and 8, exhibited a reduced singlet oxygen yield when compared to the iodine-substituted compound 6. Moreover, we conducted an evaluation of the electrochemical properties of the BODIPY compounds (1–7) in dichloromethane. Additionally, we characterized the structures of the synthesized compounds (5♦, 6, and 7) using various spectroscopic techniques, including FT-IR, HRMS, and NMR (1H, 13C, 19F, and 11B), which were performed for the first time within the scope of this study. The comprehensive findings obtained from this extensive research contribute valuable knowledge that has the potential to guide the development of highly efficacious photosensitizers for applications in photodynamic therapy. [ABSTRACT FROM AUTHOR]

Bismuth(III) complexes have been reported to act as inhibitors of the enzyme urease, ubiquitously present in soils and implicated in the pathogenesis of several microorganisms. The general insolubility of Bi(III) complexes in water at neutral pH, however, is an obstacle to their utilization. In our quest to improve the solubility of Bi(III) complexes, we selected a compound reported to inhibit urease, namely [Bi(HEDTA)]·2H2O, and co-crystallized it with (i) racemic DL -histidine to obtain the conglomerate [Bi2(HEDTA)2(μ- D -His)2]·6H2O + [Bi2(HEDTA)2(μ- L -His)2]·6H2O, (ii) enantiopure L -histidine to yield [Bi2(HEDTA)2(μ- L -His)2]·6H2O, and (iii) cytosine to obtain [Bi(HEDTA)]·Cyt·2H2O. All compounds, synthesised by mechanochemical methods and by slurry, were characterized in the solid state by calorimetric (DSC and TGA) and spectroscopic (IR) methods, and their structures were determined using powder X-ray diffraction (PXRD) data. All compounds show an appreciable solubility in water, with values ranging from 6.8 mg mL−1 for the starting compound [Bi(HEDTA)]·2H2O to 36 mg mL−1 for [Bi2(HEDTA)2(μ- L -His)2]·6H2O. The three synthesized compounds as well as [Bi(HEDTA)]·2H2O were then tested for inhibition activity against urease. Surprisingly, no enzymatic inhibition was observed during in vitro assays using Canavalia ensiformis urease and in vivo assays using cultures of Helicobacter pylori, raising questions on the efficacy of Bi(III) compounds to counteract the negative effects of urease activity in the agro-environment and in human health. [ABSTRACT FROM AUTHOR]

The chemical synthesis of 5-(4-azidophenyl)-10,15,20-tris(2-furyl/2-thienyl)porphyrins and their utilization in a Cu(I) catalyzed alkyne-azide 'click' reaction (CuAAC) with ethynylferrocene to obtain the hitherto unknown meso-tris(2-furyl/2-thienyl) substituted porphyrin–ferrocene 'click' conjugates are reported. These new 'click' conjugates were studied along with the reference 'click' conjugates containing all-meso-aryl substituted porphyrins by experimental and computational methods. Compared to the reference, the new conjugates displayed red-shifted absorption/emission bands, easier porphyrin ring reduction, and an efficient photoinduced electron transfer (PET) process from ferrocene to a porphyrin unit. Density functional theory (DFT) calculations performed on these conjugates revealed a good correlation with the experimental results. [ABSTRACT FROM AUTHOR]

Thiadiazole and selenadiazole derivatives are significant organic backbones widely utilized in drugs, bioactive molecules, and functional materials. A green and efficient one-pot synthetic methodology has been developed for the fabrication of thiadiazole/selenadiazole derivatives, which involves photocatalytic induced iodine substitution, oxydic aldehyde formation, and nucleophilic addition, resulting in C–S bond formation and hydrazylation, cyclization, and rearrangement, as well as dehydration. The present method includes good functional group tolerance, simple, mild, metal-free, and safe conditions that are in line with the principles of green chemistry, making this protocol an attractive strategy for the synthesis of bioactive molecules with thiadiazole/selenadiazole frameworks. Gratifyingly, the complanate and conjugate structures of the synthesized compounds ensured attractive fluorescent properties for successful application in biological cell imaging. [ABSTRACT FROM AUTHOR]

Indole structural motifs are ubiquitous in natural products, pharmaceuticals, agrochemicals and functional materials. The immense importance of the indole moiety, especially in the field of drug discovery, has fuelled continued attention in indole chemistry for over a century. In the recent past, a large number of metal-free methodologies have been developed apart from metal-catalyzed annulation processes. The present review focuses on recent (2019–mid-2023) efforts towards the construction of the indole core via transition-metal-free methods, which include acid-catalyzed, base-catalyzed, photochemical, electrochemical, iodonium-salt promoted, SOCl2/DMSO-mediated, uncatalyzed/thermally assisted and miscellaneous methods. The reactions described in this review mostly employed readily accessible starting materials, and inexpensive catalysts that are environmentally benign and easy to handle. In most cases, mechanistic aspects have also been highlighted for better understanding of the reaction pathways. Interestingly, some of the synthesized compounds mentioned in this review are potentially bioactive. [ABSTRACT FROM AUTHOR]

Here, we for the first time synthesized bimetallic Cu/Ag dendrites on graphene paper (Cu/Ag@G) using a facile electrodeposition method to achieve efficient SERS enhancement. Cu/Ag@G combined the electromagnetic enhancement of Cu/Ag dendrites and the chemical enhancement of graphene. SERS was ascribed to the rough metal surface, the synergistic effect of copper and silver nanostructures and the charge transfer between graphene and the molecules. [ABSTRACT FROM AUTHOR]

The dark color of industrial lignin is the main obstacle for their high value-added use in areas such as sunscreen or dyestuff dispersants. Here, a one-step method for reducing the color of lignin is presented and the structural changes of the whitened lignin are characterized by UV, FTIR, NMR, GPC, DLS, AFM, HS-GC and potentiometric titration. The results show that the content of aromatic ring, methoxyl and phenolic hydroxyl groups in the alkali lignin (AL) decreases, while the content of carboxylic groups increases when it is exposed to UV in THF. AL experiences a darkening process before it is gradually whitened. The blue shift of the UV spectrum and the decrease in size and molecular weight indicate AL is not only intermolecular and intramolecular disaggregated, but also partially depolymerized when light colored lignin is obtained. This simple but efficient whitening method is successfully practised in bleaching. The white degree of raw paper increases from 0.438 to 0.917 after being irradiated under sunshine for 3 days. [ABSTRACT FROM AUTHOR]

CrystEngCommrsc. li/ crystengcomm ISSN 1466- 8033 Volume 26 Number 17 7 May 2024 Pages 2221– 2334 PAPER Edita Garskaite et al. Assessing aspects of solution- based chemical synthesis to convert waste Si solar cells into nanostructured aluminosilicate crystals [Extracted from the article]

Exploring novel frameworks for treating Alzheimer's disease is an ambitious objective. In this particular context, a range of asymmetric biscarbothioamide derivatives (3a–l) with varying substitutions have been meticulously designed and effectively synthesized. The newly synthesized compounds have all been definitively characterized using established spectroscopic techniques such as 1H-NMR, 13C-NMR, FT-IR, and elemental analysis. In vitro, all the derivatives (3a–l) were evaluated to assess their inhibitory potential against cholinesterase enzymes (acetylcholinesterase, AChE, and butyrylcholinesterase, BChE). The outcomes demonstrated that these derivatives were potent and exhibited selectivity in inhibiting AChE, except for compounds 3b and 3e, which specifically inhibited BChE, showcasing varying degrees of KI values. Significantly, compounds 3j (KIs of 11.91 ± 2.25 nM for AChE and 77.76 ± 8.02 nM for BChE) and 3h (KIs of 14.73 ± 2.30 nM for AChE and 59.54 ± 6.20 nM for BChE) emerged as the most potent dual inhibitors of AChE and BChE within the series, respectively, with KI constants even lower than those of the standard drug tacrine (KIs of 68.70 ± 5.39 nM for AChE and 111.60 ± 10.52 nM for BChE). Furthermore, their potential scavenging activity against DPPH and ABTS radicals was evaluated. To further validate the experimental findings, molecular docking studies were performed in silico to ascertain the binding modes of these compounds with the active pockets of AChE and BChE enzymes. [ABSTRACT FROM AUTHOR]

Herein, we report the design and synthesis of a novel series of 6-((1H-1,2,3-triazol-4-yl)methyl)-6H-indolo[2,3-b]quinoxalines (22–29) via the copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) reaction. The target compounds formed through two pathways (A and B). The structures of the newly click synthesised 1,2,3-triazole-6H-indolo[2,3-b]quinoxalines (22–29) were confirmed on the basis of their elemental analysis and spectral data. Some of these compounds exhibited significant antiproliferative effects against tested cancer cells, including hepatocellular carcinoma (Hep-G2), breast cancer (MCF-7), and colon cancer (HCT116), relative to healthy noncancerous control skin fibroblast cells (BJ-1) to evaluate their cytotoxic effects. Among the tested compounds, compound 27 exhibited strong activity with IC50 = 9.3 ± 1.1, 1.5 ± 0.1, 2.4 ± 0.2, and 17.3 ± 1.2 against cancer cell lines HCT-116, HepG-2, MCF-7, and BJ-1, respectively. Therefore, compound 27 was selected for further investigation. Cell cycle analysis of liver cancer (HepG-2) cells treated with 27 showed cell cycle arrest in the S and G0/G1 phases and strong apoptotic activity, as indicated by Annexin V-FITC staining. Compound 27 was also found to fit in the ATP binding pocket during docking experiments combined with molecular dynamics simulation. Lastly, we conducted a Petra/Osiris/Molinspiration (POM) study on the synthesized compound. The most promising candidates were identified by evaluating primary in silico parameters, which showed considerable differences among individual synthesized compounds. These features can promote future drug candidate design to produce better derivatives in the search for anticancer agents, particularly those with favorable ADME parameters, low toxicity, anticipated bioactivity, and bright futures. [ABSTRACT FROM AUTHOR]

Six new coordination polymers (CPs) of cadmium based on an extended anilate-type ligand, 4,4′-(1,4-phenylenebis(azanylylidene))bis(3,6-di-tert-butyl-2-hydroxycyclohexa-2,5-dienone) (H2L), have been synthesized. The series of coordination polymers includes [Cd(L)(DMF)] (1), 1D-CP [Cd(L)(dipy-1)]·2DMF (2A) and 2D-CP [Cd(L)(dipy-1)]·DMF (2B), [Cd2(L)2(dipy-2)(DMF)2] (3), [Cd(HL)(CH3COO)(dabco)] (4) and [Cd(L)(ur)2]·(H2L) (5) (where L – deprotonated form of H2L, DMF – N,N′-dimethylformamide, dipy-1 – 4,4′-trimethylenedipyridine, dipy-2 – 4,4′-dipyridyl, dabco – 1,4-diazabicyclo[2.2.2]octane, ur – urotropine). The crystal structure and thermal decomposition of 1D- and 2D-coordination polymers are reported. The structural diversity of the synthesized compounds was found to depend on the additional neutral donor ligands in the cadmium coordination sphere. Thus, the introduction of the flexible N-donor ligand dipy-1 into the cadmium coordination sphere leads to the formation of two types of coordination polymers (1D and 2D). The use of the rigid ligand dipy-2 promotes the formation of "honeycomb" 2D-CPs. The use of shorter N-donor ligands dabco and ur leads to linear derivatives in which the ligands being coordinated by cadmium don't act as "crosslinkers" of the chains in the network. [ABSTRACT FROM AUTHOR]

Lignocellulose biorefining has great potential to replace the use of petrochemical resources in the production of fuels and chemicals. However, the full use of lignocellulose, which is depolymerized to yield mainly glucose, xylose, and lignin-derived phenolics, remains challenging. Here, we developed a glucose–xylose–phenolics (GXP) system to fully use lignocellulose for the production of L-tyrosine and its analogues in minimal medium. First, we engineered an Escherichia coli–Escherichia coli consortium carrying a CRISPR/dCas9 interference system to simultaneously use glucose and xylose to support cell growth and produce pyruvate, obtaining 34.3 g L−1 pyruvate with a yield of 0.68 g g−1 sugar. Then, we introduced tyrosine phenol lyase and other biocatalytic enzymes into this consortium to generate the GXP system, which could convert pyruvate and lignin-derived phenolics to L-tyrosine and its analogues. Using this GXP system, 20.8 g L−1L-tyrosine was produced from 12.5 g L−1 phenol with a yield of 86.4%. Using the hydrolysate of the raw material sorghum pith, 0.94 g L−1L-tyrosine was produced from 0.96 g L−1p-coumaric acid with a yield of 88.7%, and 8.1 g L−1 pyruvate remained, corresponding to an overall yield of 0.163 g product g−1 sorghum pith. The development of this GXP system illustrates a strategy for fully utilizing lignocellulosic biomass for the synthesis of value-added chemicals. [ABSTRACT FROM AUTHOR]

The most effective approach to develop new photocatalysts involves solar activation and prevention of the recombination of photogenerated hole–electron pairs. To achieve these goals, in this work, a series of bismuth oxyiodide and graphene oxide (BiOI/GO) composites were synthesized by a simple ex situ method. The structural, morphological, optical, and electrical properties of the synthesized compounds were thoroughly investigated. The photooxidation reaction of NO in the gas phase under visible light irradiation was used to assess the photocatalytic activity of BiOI/GO composites. The results showed that a small amount of GO significantly improved the photocatalytic activity. The BiOI/GO-0.5% sample prepared with 0.5 wt% GO showed the highest NO conversion (∼100%), indicating excellent photocatalytic stability after four continuous irradiation cycles and a high selectivity of 97% for nitrate ion formation. The increase in photocatalytic activity was mainly related to increased light absorption, high specific surface area, and better separation of light-generated charges. The use of chemical scavengers contributed to clarifying certain aspects of the possible photooxidation process of NO, which demonstrated that superoxide radicals (˙O2−) could be the main factor responsible for the photodegradation of NO by BiOI/GO-0.5%. [ABSTRACT FROM AUTHOR]

Organosilicon compounds are versatile reagents in chemical synthesis and materials sciences. As an important class of organosilanes, 1,1,1-trisilylalkanes can undergo various organic transformations and serve as core units for silicon-containing hyperbranched polymers. The existing catalytic approaches for accessing 1,1,1-trisilylalkanes via alkyne trisilylation not only requires pre-synthesized moisture- and air-sensitive organocalcium and organolanthanum catalysts but also suffers from limited substrate scope for both alkyne and hydrosilane reagents. For example, only alkyl-substituted alkynes can undergo organocalcium-catalyzed trisilylation with alkyl hydrosilanes to provide the desired 1,1,1-trisilylalkane products. Herein, we report a selective copper-catalyzed trisilylation reaction of both alkyl- and aryl-substituted alkynes with a readily accessible copper catalyst that is generated in situ from Cu(OAc)2 and tributylphosphine PnBu3. This copper-catalyzed trisilylation reaction features easy catalyst preparation, broad substrate scope, and mild solvent-free reaction conditions. Mechanistic studies reveal that this trisilylation reaction occurs through copper-catalyzed deprotosilylation of alkynes to form alkynylsilanes followed by double hydrosilylation of alkynylsilane. [ABSTRACT FROM AUTHOR]

Phytosulfokine (PSK) is a highly conserved plant peptide hormone (PPH) containing two sulfated tyrosine residues. PSK acts as a growth factor in Arabidopsis thaliana plant species and significantly improves the efficiency of cellular proliferation in plant cell culture, a process known as regeneration. However, many important plant species are recalcitrant under exposure to PSK and require e.g., artificially generated PPHs to boost regeneration. Here, we report the design, chemical synthesis, and biological evaluation of the regeneration capacity of a PSK-like peptide library. Our set of thirteen PSK analogues included N-terminal modifications, amino acid substitutions, incorporation of diastereomers, and backbone N-methylation. Insertion of the latter required solution-phase synthesis of the proper building block prior to solid-phase peptide synthesis. The biological activity of the PSK analogues was assessed in the regeneration capacity of Brassica oleracea cells (protoplasts). Most PSK analogues did not affect the regeneration capacity as compared to PSK. For example, when an alanine substitution was introduced and replaced either 2-Ile or 4-Thr, the bio-activity was fully abolished. However, 2-allo-Ile PSK and 4-Nme-Thr PSK showed increased activity in protoplast regeneration when compared with that of the native peptide. These findings indicated that introducing small chemical modifications in the PPH PSK provides opportunities for inducing protoplast regeneration in recalcitrant species. [ABSTRACT FROM AUTHOR]

The end-of-life recycling of crystalline silicon photovoltaic (PV) modules and the utilisation of waste is of fundamental importance to future circular-economy societies. In the present work, the wet-chemistry synthesis route – a low-temperature dissolution–precipitation process – was explored to produce aluminosilicate minerals from waste c-Si solar cells. Nanostructured crystals were produced in an alkaline medium by increasing the reaction temperature from room temperature to 75 °C. The morphology of the produced crystals varied from nanolayered aggregates to rod-shaped crystals and was found to be dependent on the temperature of the reaction medium. Chemical and phase composition studies revealed that the synthesised compounds consisted of structurally different phases of aluminosilicate minerals. The purity and elemental composition of produced crystals were evaluated by energy dispersive spectroscopy (EDS) and micro X-ray fluorescence (μXRF) analysis, confirming the presence of Al, O, and Si elements. These results give new insights into the processing of aluminosilicate minerals with sustainable attributes and provide a possible route to reducing waste and strengthening the circular economy. [ABSTRACT FROM AUTHOR]

A scalable synthesis of azidomethyl bisoxadiazol linked-1,2,3-triazole-(ABT) based potential liquid propellant and energetic plasticizer is obtained from commercially available diaminomaleonitrile in excellent yield. Newly synthesized compounds were fully characterized by various spectroscopic techniques. These materials exhibit good densities (1.77 g cm−3) and high thermal stabilities (Td = 181 °C). Compound 5 has good detonation properties (5, P = 20.81 GPa, D = 7516 ms−1) and propulsive properties (Isp (neat) = 210 s). These are superior to TNT and GAP and comparable to BAMOD, making them potential green liquid rocket propellants and energetic plasticizers. [ABSTRACT FROM AUTHOR]

In 2011, Zhang's research team, in cooperation with Li and Liu, reported the Pt1/FeOx atomically dispersed catalysts for the first time in the world, and based on this, proposed the concept of "single-atom catalysts". Single-atom catalysts (SACs) have a wide range of industrial application prospects in the catalytic synthesis of fine chemicals due to their high atomic utilization rate and special catalytic activity. With the deepening of the research, the preparation methods of SACs emerge in an endless stream, but it is still an urgent problem to realize the industrial production of highly stable SACs prepared in small batches (gram level) or even in large batches (kilogram level). In this review paper, several typical solvent-free green synthetic strategies (e.g., ball milling, physical mixing, gas migration, and pyrolyzing coordination polymers (including MOFs)) for the batch preparation of SACs are introduced. And typical catalytic application of SACs in green synthesis of fine chemicals by means of oxidation reaction, hydrogenation reaction, coupling reaction and other reactions are also introduced. This is the first review paper focusing on the mass preparation techniques of SACs and their applications in fine chemicals production. [ABSTRACT FROM AUTHOR]

The development of an immobilized enzyme for efficient biocatalysis and catalyst recycling is of great importance in cost-effective and green chemical synthesis, with the hydrolysis of cellulose to glucose for the utilization of lignocellulosic biomass as a prominent and challenging example. We developed a novel concept of engineering temperature-responsive nanobiocatalysts with an upper critical solution temperature (UCST) for efficient catalysis as a soluble catalyst at a temperature ＞UCST and for easy catalyst separation as an insoluble catalyst at a temperature ＜UCST. The first polymeric nanoparticles showing an UCST were fabricated in high yield, and the immobilization of cellulase and cellobiase onto the particles afforded the first UCST-biocatalysts, with high specific enzyme loading and enzyme loading efficiency, an UCST of 13–14 °C, and high retention of the initial hydrolysis activity of the free enzyme at 50 °C (＞UCST). The hydrolysis of insoluble cellulose, such as filter paper and pre-treated oil palm Empty Fruit Bunch (EFB, a waste biomass), with a mixture of the UCST-nanobiocatalysts containing cellulase and cellobiase at 50 °C reached the same catalytic performance as the free enzymes and gave 97% and 93% glucose yield at 2 wt% of cellulase loading, respectively. These catalytic performances are much better than any other known immobilized cellulases, due to the use of soluble catalysts. The catalysts were easily recovered at 4 °C and recycled to retain 71% and 73% productivity in the 8th and 6th reaction cycles for hydrolyzing filter paper and pre-treated EFB, respectively. The engineered UCST-nanobiocatalysts are potentially useful for the practical green hydrolysis of cellulose to glucose. [ABSTRACT FROM AUTHOR]

Nanocrystalline spinel LiMn2O4 and layered LiCo1-xMnxO2 (x = 0-0.15) cathode materials were synthesized by a rapid combustion route in combination with an annealing treatment using common filter paper as the template and ethanol as the fuel. The structure, morphology and electrochemical properties of the materials were studied by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), galvanostatic charge-discharge test, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The spinel LiMn2O4 annealed at 750 °C shows excellent cycling stability (capacity retention is 92% after 200 cycles), high coulombic efficiency (>99%) and good rate capability. The layered LiCoO2 shows high initial capacity (168.9 mAh g-1) and good rate capability, but its capacity retention is only 74% after 80 cycles owing to the nanosize effect. After doping a small quantity of Mn (x = 0.05), the cycling performance of the Mn-doped sample was significantly improved compared with that of the pristine LiCoO2 (capacity retention is 87% after 80 cycles). [ABSTRACT FROM AUTHOR]

Extending the catalytic valorization roadmap of platform molecules is one of the core tasks in the development of the biomass conversion field. Through ongoing research efforts, the transformation system of biomass-derived platform molecules has been well established and is gradually becoming relatively mature. In this context, it is of great practical interest to further explore next-generation platform molecules and their valorization pathways that have recently emerged. Linear diketones, usually derived from biomass and their C6 furan compounds, are one of the novel platform molecules that have been recently spotlighted for the synthesis of high-end chemicals due to their huge valorization potential. Herein, we intend to underline the crucial platform role that linear diketones, i.e., 2,5-hexanedione (HD) and 1-hydroxy-2,5-hexanedione (HHD), play in extending the biomass valorization roadmap to a broader one. Perspectives are concentrated on elucidating the heterogeneous tandem conversion system of biomass and its derived C6 furan compounds to HD and HHD. Also, we further demonstrate the diverse valorization routes of HD and HHD to high-end chemicals for various applications. The insights presented in this paper may contribute to highlighting the bright future of linear diketones in constructing a sustainable biomass valorization system. [ABSTRACT FROM AUTHOR]

Mechanical stiffness of oxide-type solid-electrolytes is a major drawback which has hindered their practical application in all-solid-state Li-ion batteries to date. Despite their enhanced structural and electrochemical stabilities, lack of deformability of fast-ion conducting oxides impedes the integration of these materials in bulk-type solid-state cells. Deformable solid-electrolytes such as sulfides, on the other hand, lack sufficient electrochemical stability in contact with conventional cathodes. This has recently triggered a search for new materials that combine high ion-conductivity, deformability and sufficient electrochemical stability. Here, we report the synthesis of a novel form of Li4P2O7 that can be densified by cold-pressing and possesses an ion conductivity that is two orders of magnitude higher than conventional Li4P2O7 phases. The material is synthesized by a combination of microwave synthesis and chemical lithiation and adopts a nanostructured morphology with a small amorphous component. The material is electrochemically stable at voltages >5 V vs. Li+/Li, which suggests safe use with high-voltage cathodes. The newly-synthesized material is therefore a bulk, deformable analogue of LiPON, with comparable ion conductivity and phase stability. This research highlights the potential of using novel low-temperature synthetic routes to control the morphology and enhance the electrochemical performance of conventional functional materials. [ABSTRACT FROM AUTHOR]

Fine chemical synthesis is the key area of industry and academic research, with a strong focus on catalytic C–C bond formation targeted at drug design, biologically active compounds and new materials. Until recently, such catalytic technologies had been employed without a rigorous analysis of a plausible ecological impact, which is now a key question that cannot be neglected. In this work, we experimentally classified the complete range of harmful compounds used in common Sonogashira and Mizoroki–Heck cross-coupling reactions by means of bio-Profiles (bio-Strips) built on the basis of 24 h CC50 values of individual reaction substances measured in three cell lines of different origins. For a comprehensive evaluation, 864 individual reactions and 2592 bio-Strips supplemented with bio-factors (BFs) and cytotoxicity potentials (CPs) were evaluated. According to the results, from the viewpoint of the contribution of the tested chemicals to the "overall cytotoxicity" of the synthetic routes analyzed, close attention should be paid to the selection of the catalysts due to their high cytotoxicity and to the solvents because they are used in significant quantities in the reaction. The choice of the base can also have a significant impact on the bio-Profile, whereas the effect of the starting materials seems lower in comparison. We also describe a new approach to unambiguous and quantitative comparisons of biological objects (in this case, cell cultures) in terms of their response to the continually varying conditions in reaction systems. In addition, we support the earlier-suggested notion that the choice of a particular cell line for CC50 measurements can be of secondary importance for the resulting bio-Strips. Nevertheless, the actual cytotoxicity of a given compound should not be ignored when selecting the participant components for a target reaction, as evidenced by the newly introduced "tumor selectivity index" (tSI) of individual chemicals. A detailed analysis of these two practically important catalytic reactions also provides a guide and a global view for assessing the bio-risks of other catalytic processes. [ABSTRACT FROM AUTHOR]

Multicomponent reactions (MCRs) have demonstrated enormous potential in the direct and single-step synthesis of chemical entities with structural diversity. However, the photochemical MCR approach for the construction of N-heterocycles, particularly functionalized ones, from non-heterocyclic synthons remains relatively unexplored. Herein, we report a modular assembly of CF3-modified 3,4-dihydroquinazolinones from basic building blocks using a one-pot light-driven multicomponent approach. In this protocol, the latent capability of 1-(2-acetylphenyl)-3-phenylurea to reach a reactive triplet state upon energy transfer (EnT) activation while successfully triggering intramolecular cyclization is disclosed. Medicinally relevant 3,4-dihydroquinazolinones could be feasibly synthesized from commercially available 2-aminoacetophenone, p-tolyl isocyanate, and Togni's II, offering a metal-free construction with broad functional group tolerance. Mechanistic investigations revealed EnT mediated intramolecular cyclization and single electron transfer (SET) mediated hydroxytrifluoromethylation cascade reactions in this novel process. Density functional theory calculations illustrated the energy landscape of this photoinduced transformation. [ABSTRACT FROM AUTHOR]

Herein, a novel synthetic methodology was devised to synthesize cis-3-aroyl-urea-β-lactams by reacting aroyl isoselenocyanates with cis-3-amino-β-lactams in a THF : H2O mixture (9 : 1). This synthetic approach eliminates the previous requirement for the challenging synthesis of unstable aroyl isocyanates and the low-yield acylation of urea to obtain aroyl urea derivatives. Further optimized conditions for nucleophilic reaction of aroyl isothiocyanates with cis-3-amino-β-lactams to obtain cis-3-aroyl-thiourea-β-lactams were developed. The stereochemistry of cis-3-aroyl-thiourea/urea-β-lactams (5a–f/8a–f) was elucidated by analyzing the J values of C3–H and C4–H of β-lactams. Subsequently, we evaluated the antibacterial activity of these compounds against both Gram-positive bacteria (S. aureus and B. cereus) and Gram-negative bacteria (P. aeruginosa and E. coli). Remarkably, among all the synthesized compounds, 8e exhibited potent activity against all bacterial strains, with a notable MIC value of 6.25 μg mL−1 against B. cereus, surpassing ampicillin (MIC = 25 μg mL−1) by four-fold. Additionally, compounds 8d and 8e demonstrated promising antifungal properties, with an MIC value of 1.5 μg mL−1 against C. tropicalis, comparable to fluconazole (MIC = 1 μg mL−1). Furthermore, compounds 8d and 8e exhibited 80% and 75% cell viability against THLE-2 cells at a concentration of 25 μg mL−1. Molecular docking analysis provided additional support for the observed in vitro antibacterial and antifungal activities of compound 8e. [ABSTRACT FROM AUTHOR]

Metal-free synthesis of highly functionalized (E)-stilbenes cored with electronic donor and acceptor functionalities was achieved through a carbanion-induced ring transformation reaction between (E)-4-(4-(dimethylamino)phenyl)but-3-en-2-one 12 and 6-aryl-2H-pyran-2-ones 9 in the presence of a base. The procedure has several advantages, including mild reaction conditions, readily available precursors, metal-free synthesis, simple setup, and the synthesis of various substituted regioselective (E)-stilbenes in good yields. All the synthesized compounds 13a–j were found to be thermally stable and exhibited fluorescence in the range of 436–490 nm. A considerable positive solvatochromic behaviour in different solvents of varying polarity was observed, and the concentration study indicated the non-aggregating behaviour of all the synthesized compounds. [ABSTRACT FROM AUTHOR]

Dicyanamides of d-metals provide a wide range of magnetic properties tuned by external cations, encapsulated ions, and coordination modes of anions. Analysis of molecular, one-periodic (1D chain), twoperiodic (2D layered), and three-periodic (3D framework) networks formed by transition metals in their dicyanamides was carried out. All dicyanamides were treated as systems of nodes (metal centers and polytopic ligands) and spacers (bridge dicyanamide anions and co-ligands). The most typical coordination numbers, the role of the dicyanamide, and the effect of terminal and chelate co-ligands on the dimensionality and type of overall architecture were described. A knowledge-based system to predict possible architectures of novel dicyanamides was described and tested on samples of five complexes. The synthesis and spectroscopic and structural properties of the synthesized compounds were described. It was demonstrated that the novel compounds realize square lattice (sql), honeycomb (hcb)orsimplechain (2C1) motifs, which were estimated to be the 1st and the 2nd of the most abundant topologies for 2D networks and the most expected 1D motif, respectively. [ABSTRACT FROM AUTHOR]

Droplet microfluidics is an emerging tool in many biological and chemical application areas such as digital polymerase chain reaction (PCR) and in vitro diagnosis because of its extremely small sample volume and wide range of possibilities for on-demand adjustment of droplet properties. Although centrifugal microfluidics has been reported as a viable scheme for droplet generation, there is not much progress as far as droplet manipulation and droplet-based reactions are concerned. In this paper, we report a microfluidic pressure regulator scheme along with the use of microcapillaries for periodic droplet generation and the subsequent fusion. This scheme enables fine control over droplet generation and the fusion process by varying the rotational frequency. To control the solution concentration in droplets, we have implemented several fusion devices, including one-to-one mode using a symmetric structure and ratio-adjustable mode with an asymmetric structure. As an application example, we performed cell transfection using the reported droplet-based technique, which resulted in considerable improvement in terms of transfection efficiency compared to the traditional bulk approach. In another example, we synthesized quasi-2D perovskites with controllable compositions and tunable photoluminescence peaks, thus confirming the volumetric accuracy of this approach down to the nano-liter scale. Compared to the common pressure pulsation approach, our centrifugal force actuation scheme offers the advantages of compactness and highly parallel batch processing. We anticipate that the new scheme will find many applications in cell biology and chemical synthesis. [ABSTRACT FROM AUTHOR]

Polyaromatic-based dual-dye integrated azaborondipyrromethene (azaBODIPY), 1 containing pyrene and naphthalene at the 1,7- and 3,5 positions, respectively, was synthesized and the photo-induced energy (PEnT) and electron transfer (PET) events were explored. The contribution of the individual constituents i.e., pyrene, naphthalene, and azaBODIPY moieties, in the light-initiated events is investigated by preparing the azaBODIPY centric control compounds containing pyrene, 2 or naphthalene, 3 and tolyl moieties, TABPY. The structural integrity of the synthesized compounds is elucidated by NMR and HRMS techniques. Spectral overlap of the emission of pristine naphthalene, Naph and absorption of TABPY suggested that the naphthalene moieties in 1 and 3 would behave as energy donors and azaBODIPY as an energy acceptor. On the other hand, electrochemical studies on 1 and 2 suggested that, upon photoexcitation, pyrene moieties flanked on the azaBODIPY core can act as electron donors and an azaBODIPY moiety as an acceptor, which was further supported by in silico studies. Steady-state fluorescence studies revealed that, upon selective excitation of 3 at 275 nm, the fluorescence corresponding to the naphthalene moiety was observed to be quenched, followed by the simultaneous appearance of the azaBODIPY emission at 694 nm indicating the occurrence of PEnT from 1Naph* → azaBODIPY. In the case of 2, the photoexcitation of either pyrene or an azaBODIPY moiety at 335 and 660 nm, respectively, displayed diminished emission of pyrene and azaBODIPY indicating the occurrence of PET from 1Pyr* → azaBODIPY or Pyr → 1azaBODIPY*. Interestingly, excitation of the naphthalene moiety in 1 resulted in the quenching of its emission with a concurrent quenching of the azaBODIPY fluorescence indicating the occurrence of PEnT from singlet excited naphthalene to azaBODIPY i.e., (Pyr)2-azaBODIPY-1(Naph)2* → (Pyr)2-1azaBODIPY*-(Naph)2 followed by PET from the ground state of the pyrene moiety to 1azaBODIPY* leading to the formation of the charge separated state, (Pyr)2˙+-(azaBODIPY)˙−-(Naph)2. Parallel time resolved fluorescence studies revealed that the PEnT and PET are occurring in the range of ∼109–1010 s−1 in these donor–acceptor (D–A) systems. [ABSTRACT FROM AUTHOR]

A highly efficient protocol has been developed in this work to synthesize promising pharmacophore synthons, namely 4-hydroxybenzophenones (4-HBP), with yields ranging from 80–99%. Interestingly, the method utilizes p-QMs as substrates and involves a single-pot, two-step alkoxylation/oxo-demethoxylation reaction sequence that uses easily accessible Amberlyst-15 and DDQ, respectively, in methanol at room temperature. The protocol demonstrates a broad substrate scope for diverse p-QMs with excellent functional group tolerance and complete regioselectivity for oxidation at the methide group. Moreover, the synthesized compounds 1 could be readily dealkylated to 4-HBPs (9), a key starting material of top-selling drugs. The simple starting materials, and the scalability (1 g) and recyclability of both Amberlyst-15 and DDQ over at least five cycles make the protocol eco-friendly and commercially viable. [ABSTRACT FROM AUTHOR]

A simple and efficient fluorescent probe (E)-4-bromo-2-((((5-methylfuran-2-yl)methyl)imino)methyl)phenol (BFMP) for the detection of Zn2+ ions was synthesized by the condensation of 5-methyl-furfurylamine and 5-bromosalicylaldehyde. Elemental analysis, LC-MS, ATR-IR spectroscopy, and NMR (1H and 13C) spectroscopy were performed to confirm the structures of the Schiff base ligand and its Zn(II) complex. Further, the molecular structure of BFMP was confirmed by single-crystal XRD. It is noteworthy that BFMP displayed favourable behaviour of the florescent active molecule. The BFMP solution was yellow, which after the addition of the Zn2+ solution became colourless, as observed by the naked eye. Moreover, under ultraviolet (UV) radiation, a maximum absorption at 425 nm and a large fluorescence enhancement at 560 nm were observed. BFMP was very selective to Zn2+ ions, even in the presence of other metal ions. This includes Cd2+, which has a binding constant (Ka) of 1.74 × 106 M−1, and a detection limit of this finding suggested that a fluorescence probe (BFMP) can be used to detect Zn2+ by colorimetric detection. The detection limit can reach up to 0.249 × 106 M−1. Furthermore, the efficiency of the ligand was tested using real water samples (lake and tap water), and the results revealed that BFMP acted more efficiently in both the tested water samples. The geometries of BFMP and BFMP–Zn2+ were investigated by the density functional theory (DFT) method using the B3LYP method with 6-311++G(d,p) and LAN2LZ basis sets, respectively. The optimized geometrical parameters obtained by the DFT calculation are in good agreement with the X-ray crystal structure data. [ABSTRACT FROM AUTHOR]

Cellulose is the most abundant, renewable carbohydrate resource in nature, providing human society with a broad spread of materials for production and living. Compared with the mature textile and paper industries, technologies for cellulose utilization to produce energy and chemicals are still under development. In particular, the depolymerization of cellulose to glucose and further transformation into various fuel compounds or chemicals has received considerable attention as a sustainable approach to address the energy crisis and environmental issues raised by massive fossil consumption. Among various cellulose derived molecule types, ester is one of the most appealing owing to its unique physicochemical properties, reactivities and functions. This review summarizes recent advances in the chemical synthesis of esters from cellulose and its derivatives. Various esters, including alkyl levulinates, γ-valerolactone, valerates, pentenoates, lactates etc., have been effectively prepared from cellulose feedstock or its downstream platform compounds. The catalytic systems were highlighted with rational integration of the active sites for the tandem reactions involved in the conversions. The kinetics, process integration, selectivity control and catalysis mechanism were also discussed in detail. Finally, an outlook of the future direction, as well as the challenges, for cellulose ester production were also illustrated. [ABSTRACT FROM AUTHOR]

The paper dwells on the synthesis and diverse studies of cyclically arranged hydrogen bridges in tris-hydroxy aryl Schiff bases. Experimental (IINS, IR, Raman and X-ray) and theoretical (CPMD, DFPT and DFT) studies of tris-hydroxy aryl Schiff bases have been performed in the solid state. This is the pioneer spectroscopic investigation of mutual interactions between hydrogen bridges in a cyclic arrangement. The spectroscopic studies have been carried out by IR, Raman and IINS experimental methods and supported by density functional theory (DFT), plane-wave periodic theory (DFPT) and Car–Parrinello Molecular Dynamics (CPMD) calculations. A study of the impact of steric squeezing on the strength of hydrogen bonds is presented. The remarkable dynamics of the bridged protons in the studied Short Strong Hydrogen Bond (SSHB) has been investigated on the basis of first-principles CPMD calculations. The fundamental investigations of the hydrogen bridge vibrations have been accomplished on the basis of isotopic substitutions (NH → ND and OH → OD) and vibrational Potential Energy Distribution (PED) analysis. [ABSTRACT FROM AUTHOR]

Cauliflower-like NiCo2S4 nanoparticles (NPs) for use as battery-type materials have been synthesized via a simple one-step route solvothermal method with thioacetamide (TAA) as the sulfur source. The synthesis of the Ni–Co precursors and the S2− anion exchange reactions occur at the same time, which is time-effective and cost-effective compared to other methods. The obtained NiCo2S4 NPs display very competitive electrochemical performance (a specific capacitance of 2480 F g−1 is achieved at a current density of 0.5 A g−1, excellent rate capability with 68% of the original capacitance remained at 10 A g−1 and ideal cycle stability with 80% capacitance remained after 3000 cycles) with high mass-loading (5 mg cm−2). In addition, low-cost activated balsam pear pulp (ABPP) is developed as a capacitor-type carbon material for supercapacitors with ideal electrochemical performances. The asymmetric hybrid capacitors (AHCs) are further assembled into pouch cells using battery-type NiCo2S4 NPs as the positive electrode, capacitor-type ABPP as the negative electrode and flexible carbon papers as the current collector. The AHCs demonstrate high power density (3.52 kW kg−1 at an energy density of 3.72 Wh kg−1) and cycle stability (72.4% after 9000 cycles). [ABSTRACT FROM AUTHOR]

Nowadays, there is a growing emphasis on environmental considerations, leading to an increased importance being placed on green and sustainable methods in the field of organic chemistry. It is crucial that protocols are not only effective to afford the desired results but also operate under safe conditions, with reduced reaction times, and minimal generation of harmful waste products. Within the realm of synthetic organic chemistry, esterification and reduction of aromatic carboxylic acids hold significant importance as they enable the synthesis of crucial chemicals. To this end, we have developed a chemo-selective reduction method for aryl carboxylic acids. This method utilizes the solid acid catalyst copper phthalocyanine tetrasulfonic acid (CuPcS) and sodium borohydride in tetrahydrofuran (THF) at ambient temperature. In addition, we have developed a new technique for the esterification of carboxylic acids using CuPcS as a catalyst for the chemo-selective reduction method. This novel approach offers several advantages, including reduced reaction times, enhanced safety conditions, and straightforward methods for isolating and recycling CuPcS. These improvements contribute to increased efficiency and sustainability in the esterification process. [ABSTRACT FROM AUTHOR]

A bottom-up synthesis of titanate nanoflakes with euhedral shapes was accomplished by an aqueous solution process. Crystal growth by bottom-up synthesis utilizing chemical reactions has a possibility to produce crystals with euhedral shapes. Close packing of nanoflakes with a euhedral shape and a uniform size in the in-plane direction would enable the fabrication of large polycrystalline nanosheet thin films. However, the bottom-up synthesis of metalate nanosheets that we have been studying is prone to yielding small and indistinct nanoflakes. In this study, it is revealed that both the removal of an amorphous phase and relatively large lateral sizes are required for the formation of euhedral shapes. The addition of organic ligands to reaction sols is useful for such a synthesis of titanate nanoflakes. The addition of lactic acid and triethanolamine yielded transparent aqueous sols containing titanium species by inhibiting the formation of insoluble amorphous phases. Moreover, the combination of triethanolamine as an organic ligand and tetrabutylammonium hydroxide as a base exhibited a high sol-state stabilization effect because of their interaction with the surface of formed titanate nanoflakes. Furthermore, further crystal growth of preformed titanate nanoflakes in a fresh reaction sol including both triethanolamine and tetrabutylammonium hydroxide provided many titanate nanoflakes with rhombic shapes, which are euhedral shapes. [ABSTRACT FROM AUTHOR]

The increasing water pollution due to toxic dyes is a matter of concern from an environmental point of view because it has a long-term impact on animal and plant life. Photocatalysts act as a saviour that can degrade these organic molecules under visible and/or solar light. However, achieving enhanced luminescence performance, reusability, and high stability is challenging with affordable photocatalysts. In this work, a Ag–CdS composite nanomaterial with a unique cross-linked shell morphology was synthesized via a simple and cost-effective chemical method. In a wet chemical synthesis method, Na2S (sodium sulfide) releases S2− ions, which react with Cd2+ ions in the presence of Ag nanoparticles and capping agent trisodium citrate (TSC), neutralizing the possibilities of over-aggregation. Therefore, the controlled growth of the Ag–CdS composite resembled a cross-linked structure comprising shells of CdS nanoparticles with Ag in the centre. The composition and morphology of obtained heterostructures were investigated by XRD (X-ray diffraction), XPS (X-ray photoelectron spectroscopy), and electron microscopy. The photoelectrochemical and photoluminescence behaviour was examined, which explained the trend of catalytic properties. The photocatalytic behaviour was finally observed with Rhodamine 6G (R6G) and methylene blue (MB), which are considered among the most resistant dyes and showed significant improvement of catalytic response over the previously reported Ag–CdS nanocomposites with ∼98% and 94% degradation after 105 min and 120 min, respectively. [ABSTRACT FROM AUTHOR]

A series of dicationic ionic liquids (DcILs) (1–5), with varying lengths of alkyl chain along with [FeCl3Br]− as the counter anion, have been synthesized and are characterized by using FT-IR, Raman spectroscopy, and mass spectrometry besides single crystal X-ray analysis. The thermal stability, chemical and elemental composition of the synthesized compounds are assessed by thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS) respectively. They have been exploited as extractants and catalysts for oxidative desulfurization (ODS) of liquid fuels using H2O2 as an oxidizing agent. Certain parameters like the effects of reaction time, temperature, catalyst loading amount, oxidant-to-sulfur ratio, and reactivity of different sulfur substrates on desulfurization have also been surveyed comprehensively. The synthesized DcILs exhibit very efficient extractive and catalytic activity with the advantage of very mild reaction conditions, rapid reaction equilibrium, and substantial sulfur removal at room temperature with minimal amount of catalyst and oxidant. A reaction mechanism of DcILs with DBT has been proposed and its kinetics appeared to be a pseudo-first-order reaction. The extraction and catalytic oxidation (ECODS) process has been explicated and authenticated by GC-MS. The present work demonstrates that DcILs have the least contribution to the contamination of liquid fuels as they are insoluble in them and due to higher recyclability, they may be attributed as green and eco-friendly extractants as well as catalysts. [ABSTRACT FROM AUTHOR]

Both polyoxometalates (POMs) and organic small molecular catalysts show excellent performance in chemical synthesis. The incorporation of nanoscale POMs and organocatalysts allows the full expression of their respective merits and enables elusive reactions to be achieved in one catalytic system. However, the covalent combination of such two components has been rarely explored. Here, we have successfully designed and synthesized a bifunctional nanomolecular catalyst L -Pro-Mn-Anderson by grafting L -proline onto an Mn-Anderson POM for the first time, and catalytic experiments show that L -Pro-Mn-Anderson can realize the one-pot alcohol oxidation/three-component reaction to synthesize two types of heterocyclic compounds (5-aryl-pyrimido[4,5-b]quinoline-dione derivatives and pyrazolo[3,4-b] pyridine derivatives) in high yields up to 97%. The detailed characterization of the catalyst and the catalytic mechanism has shown that L -Pro-Mn-Anderson exhibits synergistic effects that combine both organic and inorganic catalytic functions, and the covalent linkage improves the overall redox activity of the molecular catalyst. This study opens up a new way for the design and application of covalently combined organic–inorganic molecular catalysts toward de novo organic synthesis. [ABSTRACT FROM AUTHOR]

Two series of L -quebrachitol derivatives have been designed and synthesized in order to search for novel hypoglycemic agents. The α-glycosidase inhibitory activities of these compounds were evaluated, and their structure–activity relationships (SARs) were discussed. Using Acarbose as the positive control, the activities of 16 synthesized compounds against α-glycosidase were evaluated with 4-nitrophenyl-α- D -glucopyranoside as a substrate. The results showed that 16 compounds had significant inhibitory activities against α-glycosidase and 8 compounds (6b, 3b, 3c, 3e, 3h, 3i, 3j, and 3l) out of them had stronger inhibitory activities than Acarbose. Furthermore, 3i has the strongest activity, which is 20 times stronger than that of Acarbose. [ABSTRACT FROM AUTHOR]