Search

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

According to the requirements of sustainable green development, the efficient green synthesis of fluorine chemical products is an inevitable trend. In this work, we used ionic liquids as an effective catalyst in an important fluorochemical reaction – hexafluoropropylene dimerization for the first time. The effects of ionic liquids with different spatial positions, substituents and nucleophilic anions on the catalytic performance of hexafluoropropylene dimerization were systematically studied. The results showed that the strong nucleophilic trisubstituted thiocyanate imidazole ionic liquid [C6mmim][SCN] had the highest activity under the optimum reaction conditions, the turnover frequency (TOF) was 108.36 h−1 and the selectivity was 97.96%. Compared with the traditional metal salt catalyst system, the catalytic activity of ionic liquids was double. In addition, based on the XPS analysis results and density functional theory (DFT), a possible reaction mechanism was proposed. The effective catalytic activity of ionic liquids was mainly attributed to the strong nucleophilicity of anions and the weak interaction between cations and anions. This work will successfully provide a green synthesis route for hexafluoropropylene dimerization and further promote the efficiency and greening of fluorine chemical reactions. [ABSTRACT FROM AUTHOR]

Compounds containing 1,2,4-triazoles and hydrazone structural frameworks have been widely studied and demonstrated to exhibit a wide range of pharmacological properties. In this work, a descriptive series of new hybrid compounds with a 1,2,4-triazole ring and a hydrazone moiety were designed and synthesized by oxidative cyclization of thiourea derivatives using molecular iodine under mild conditions. The structure of synthesized compounds was characterized by employing different spectral techniques including FTIR, 1H NMR, 13C NMR, HRMS, and X-ray analysis. Furthermore, the proposed structure of BIH2 was resolved using single-crystal X-ray analysis. The compounds were evaluated for their in vitro anti-breast cancer activity and the most promising compound BIH4 with a methyl group substituted to a benzene ring exhibited significant dose-dependent cytotoxicity with selectivity to MDA-MB-231 cells in a Resazurin assay. The investigation of cell cycle progression analysis of the most active compound using a flow cytometer displayed a cell cycle arrest in the sub G1 phase. Furthermore, molecular modeling studies for the synthesized compounds were performed to predict their binding affinities toward the active site of BCL-2. The findings of the molecular modeling investigations were highly consistent with those of the cytotoxicity results. [ABSTRACT FROM AUTHOR]

Recently in the field of chemotherapeutics, to combat the side effects of cisplatin, ruthenium complexes have been investigated extensively. In this work, a bidentate benzimidazole-based ligand, HL [HL = 2-(1H-benzo[d]imidazol-2-yl)-6-methoxyphenol], was utilized to obtain three Ru(II) arene complexes having a generalized formula [Ru(η6-p-cym)(L)(X)] or [Ru(η6-p-cym)(L)(X)]+ (where p-cym = p-cymene). The co-ligand X (X = (i) Cl, (ii) PPh3 = triphenyl phosphine, and (iii) PTA = 1,3,5-triaza-7-phosphaadamantane) was varied in order to study the effect it has on the antitumor activity of the compounds. The synthesized compounds were thoroughly characterized using different analytical techniques, including ESI-MS, NMR, FTIR, UV-Vis, and fluorescence spectroscopy. A fluorescence quenching experiment with serum albumin proteins revealed good interactions between the complexes and HSA and BSA. An analysis of their lipophilic character via the shake flask method and a stability study using UV spectroscopy were conducted as well. The anticancer properties of the synthesized compounds were further explored by conducting a DNA binding study using absorption spectroscopy and fluorometric titration with DAPI to check the mode of binding with DNA. Interestingly, the complexes were also found to catalyze the oxidation of NADH to NAD+, giving rise to radical species in the cells. An immunoblot analysis strongly suggested that all three complexes can remarkably upregulate the expression of cleaved caspase-3 and downregulate the expression of the anti-apoptotic protein BCLXL. It is important to note that such studies are yet to be reported for similar benzimidazole-based ruthenium complexes and therefore present a new direction for the investigation of antitumor ruthenium-based metallodrugs. Furthermore, Hoechst and AO/EtBr staining was used to analyze the morphological changes of the compound-treated cancer cells due to apoptosis, which was also confirmed by the IC50 values obtained from the colorimetric assay (MTT) against different cancer cell lines. [ABSTRACT FROM AUTHOR]

Despite attempts to reinforce the significance of solvent selection, the adoption of green solvents is relatively immature since their practicality remains unclear in the membrane arena. This work demonstrated the integration of life cycle assessment (LCA) and techno-economic analysis (TEA) to appraise both environmental and economic perspectives of green solvents in fabricating 1 m2 of polyimide flat sheet membranes. This analysis compared the impacts of a conventional solvent and three green solvents, namely N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), ethyl acetate (EA), and γ-butyrolactone (GBL). Other than the solvents, the impacts of two different synthesis methods such as chemical imidization and one-step high temperature polymerization were investigated. The impact assessment indicated that the membrane preparation process imposed the greatest environmental burden on human health due to toxicity impacts. Noticeable impact decrements were spotted by replacing NMP with a less toxic green solvent in membrane fabrication. However, a green solvent such as DMSO was less competitive in terms of production costs. Integrating the results from LCA and TEA, DMSO and EA were suggested as potential green solvents by virtue of their decent environmental performance and costs. The impact of synthesis approaches was negligible based on the findings, but is anticipated to be more evident when the membrane production process is scaled up. [ABSTRACT FROM AUTHOR]

Lignin chemistry is regarded as one of the core components in the field of biomass catalytic conversion. Over the past decade, the catalytic synthesis of value-added chemicals or biofuels via oxidation/reduction depolymerization with lignin as the initial substrate has made extensive progress through ongoing research attempts. However, there are fewer investigations on the conversion of lignin derivatives to nitrogen-containing compounds such as aniline and benzylamine through heterogeneous catalytic amination. On this account, this paper reviews the amination value-added reaction processes of lignin-derived phenols, ethers, carbonyl compounds and alcohols to produce aniline and benzylamine, mainly focusing on cheap catalysts, green solvent systems, nitrogen source systems, and mild reaction conditions, which can provide novel perspectives to promote the processive innovation of a sustainable lignin amination system. The perspectives on the synthesis of lignin-based aniline and benzylamine proposed in this review are intended to offer novel research ideas for further expanding the boundaries of the biomass refining systems involving lignin amination chemistry. [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]

N-Halamine-based antibacterial polymers play a significant role in controlling microbe-associated surface contamination. Hydantoin-containing polymers are usually synthesized by tethering polymerizable moieties to 5,5′-dialkyl hydantoin. However, such approaches sacrifice the imide hydrogen in the molecule, thereby restricting the halogen capture only to the amide nitrogen. In this paper, we report the synthesis of a novel polymerizable hydantoin monomer containing one more amide group in addition to the amide and imide groups already present in hydantoin to maximize the halogen capture and hence its antibacterial activity. The synthesized monomer was copolymerized with methyl methacrylate (MMA) and styrene. The monomer and its copolymers were characterized using 1H and 13C NMR, HRMS, FTIR, XPS, TGA, DTA and GPC. The oxidative chlorine content of the copolymers ranged from 0.9% to 1.21%. The polymers were spin coated onto glass surfaces to study their antimicrobial potential. The polymer-coated glass surfaces exposed to both Gram positive S. aureus and Gram negative E. coli bacteria using standard protocols showed total kill of the bacteria within 15 minutes of exposure. These new hydantoin polymers showed highly superior antibacterial activities compared to many such polymers reported so far in the literature. [ABSTRACT FROM AUTHOR]

Three new complexes of palladium(ii) floroquinolone drugs (levofloxacin (HLVX), pefloxacin mesylate (HPFX) and lomefloxacin (HLMX)) were prepared in alkaline media at pH = 9. The suggested chemical formula was assigned as [Pd(L)2] (where L = LVX, PFX and LMX). These complexes were explored by elementary analyses, conductivity tests, infrared and proton NMR spectroscopy, and thermogravimetric analysis and its deferential tools. The homogeneity, surface morphology and particle size of the as-synthesized solid palladium(ii) complex were investigated using X-ray powder diffraction and transmittance electron microscopy. FT-IR and 1H-NMR spectroscopy techniques. The results reveal that HLVX, HPFX and HLMX fluoroquinolones act as bidentate chelates coordinated to the palladium(ii) central metal ion via the oxygen of carboxylate and carbonyl groups. The palladium(ii) metal ion produces a stable six-membered ring with distorted octahedral structure. The conductivity measurement results deduced that these chelates are non-electrolytic in 1 : 2 stoichiometric ratio. Thermal analysis (TG/DTG) was applied to ascertain the stability of the as-synthesized complexes in comparison to free floroquinolone drugs. The thermal decomposition pathways show that the final residual product is pure PdO. Thermodynamic parameters such as energy of activation E*, entropy ΔS*, enthalpy ΔH* and Gibbs free energy ΔG* of activation were calculated using Coats–Redfern and Horowitz–Metzger non-isothermal techniques. The particle sizes of palladium(ii) complexes were measured within nanoscale range, dependent on morphological tools (XRD and TEM). Molecular docking assessment of the three floroquinolones against prostate cancer mutant 2q7k-hormone receptor is discussed. To our knowledge, this paper presents the first-time synthesis and physicochemical characterizations of a coordination complex of palladium(ii) metal ions with floroquinolone and its use as a medicinal model against cancer cells. [ABSTRACT FROM AUTHOR]

Mesoporous hydroxyapatite (MPHA) particles have recently gained a great deal of interest in a broad range of fields including biomedical fields, wastewater treatment and catalysis. In this paper, we describe a novel and convenient route to synthesise MPHA particles using calcium carbonate nanoparticle templates for the formation of mesopores in HA. In this method, both nano-CaCO3 templates and HA are prepared simultaneously using calcium sucrate as a precursor by allowing the nano-CaCO3 to embed in HA. Mesopores in HA are obtained by removing the template. The porosity of HA is confirmed by Brunauer–Emmett–Teller (BET) analysis and the average pore size (below 50 nm) is determined from Transmission Electron Microscopy (TEM) images. The synthesized material is noncytotoxic as confirmed by cytotoxicity studies, which makes it a potential candidate as a biomaterial for biomedical applications. Furthermore, the MPHA shows a superior adsorption ability towards Pb2+ Ni2+ and Cd2+ in aqueous solutions, and could also be used as an environmental-friendly material for wastewater treatment and water purification. Therefore, we believe that this simple and novel synthesis route for the fabrication of porous HA could be useful in fulfilling the current demand for HA in biomedical and water purification applications. [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]

Several cationic rhodium(I) complexes [Rh(COD)L2][C5(CF3)5] have been synthesized through substitution of the weakly bound [C5(CF3)5]− ligand from [Rh(COD)(C5(CF3)5)], further emphasizing its unique reactivity. Besides acetonitrile, pyridine derivatives with varying degrees of fluorination have been employed as ligands in order to investigate the influence of fluorination upon the binding affinity towards the resulting [Rh(COD)]+ fragment and the limit as to which the [C5(CF3)5]− ligand can be displaced. Furthermore, the newly synthesized compounds represent rare examples of rhodium complexes containing fluorinated pyridines as ligands. [ABSTRACT FROM AUTHOR]

The efficient synthesis of lactide with high purity is the key to poly-lactic acid (PLA) production. Here, we demonstrated a 2D COFs-based catalyst, which could convert L -lactic acid into L -lactide directly in an excellent yield (80%) under mild conditions. Similar to enzymatic catalysis in which the product selectivity is controlled by the enzyme pocket, the precision confinement effect of the highly ordered channels and adjustable structures with functional moieties of the COFs play key roles in converting the monomer to the cyclic dimer directly and avoiding oligomerization. This strategy is sharply different from the current two-stage process for synthesizing lactide. The reactions are carried out at a lower temperature and under atmospheric pressure, which reduces the energy consumption significantly. In addition, this newly developed method avoids the use of metal catalysts and meets the demands of the environmental friendly trend in chemical synthesis. Last, the functions of the emerging COFs materials as excellent heterogeneous catalysts with a confinement effect were further explored. [ABSTRACT FROM AUTHOR]

In an attempt to develop novel α-amylase inhibitors, a series of 2,4-thiazolidinedione fused spiropyrrolidine-oxindole and 1,2,3-triazole scaffolds were designed, synthesized via a multi-component approach and characterized using IR, 1H NMR, 13C NMR and DEPT based spectral studies. The exact structure of 9a was confirmed using single-crystal X-ray diffraction studies. The presence of various non-covalent interactions in the molecular structure of 9a was explored using Hirshfeld surface and PARST analysis. All of the synthesized compounds were assessed for in vitro α-amylase inhibition using acarbose as a positive standard. Compound 9b depicted maximum inhibition; 88.05 ± 2.51%, 76.65 ± 2.19% and 68.57 ± 1.96% inhibition at 50, 25 and 12.5 μg mL−1, respectively, relative to standard drug acarbose (77.96%, 71.17% and 67.25%, at 50, 25 and 12.5 μg mL−1 concentration). In silico docking simulations were used to investigate the binding of the compounds within the binding pocket of α-amylase (PDBID: 7TAA). Molecular dynamic simulations revealed the stability of the docked ligand–protein complexes. [ABSTRACT FROM AUTHOR]

A variety of phenylene-bridged isoxazole and tetrazole-1-ol based green energetic materials was synthesized, for the first time, in good to excellent yields. The structures of the newly synthesized compounds were confirmed by spectroscopic techniques, elemental analysis, and single-crystal X-ray analysis. The value of the present work is that all newly synthesized compounds have good thermal stabilities ranging between 167–340 °C and acceptable densities between 1.51 g cm−3 to 1.82 g cm−3. Detailed computational insight into the energetic properties of the new compounds shows that they have good energetic properties (propulsive and ballistic) with excellent thermal and mechanical stabilities which makes them promising candidates for solid propulsion systems. Compounds 5, 12 and 14 are the superior candidates as melt-castable energetic materials. [ABSTRACT FROM AUTHOR]

Consolidated bioprocessing (CBP) is a promising approach to directly convert lignocellulose feedstocks into targeted biochemicals and biofuels, and is commonly executed by single engineered microorganisms. Alternatively, the complex metabolic functions can be compartmentalized into different specialized microorganisms by using microbial consortia. In this study, a simplified microbial consortium was reassembled consisting of the lignocellulose degrader Trichoderma asperellum and lactic acid (LA) producer Lactobacillus paracasei, which were derived from the same native microbial consortium. The novel strategy of "learning from nature" combined with "simplifying the native microbial consortium" successfully increased cellulosic LA production from 7.36 g L-1 (native microbial consortium) to 57.57 g L-1 owing to the members' co-operation. Especially, over 80% carbon flux flowed from Avicel into LA synthesis with a yield of 0.92 g g-1. Furthermore, these two members can co-exist after compartmentalization into different spatial structures based on an aggregated granule of hydrogel-embedded L. paracasei and the formed biofilm of T. asperellum, leading to a 29.41% increase of LA productivity. This successfully constructed microbial consortium creates individual ecological niches to meet different oxygen demands, which enables more efficient co-operative performance in LA production from lignocellulose biomass. The analysis of interactions between these two members also provides insights on synthetic microbial consortium construction for the synthesis of other chemicals. [ABSTRACT FROM AUTHOR]

In this paper, we describe the effective synthesis of oxatruxene and its photophysical, electrochemical and structural features that transpire when a methylene unit in a truxene core is replaced by an oxygen atom to yield 5-oxatruxene. This modification broke the C3h symmetry and at the same time introduced a more electronegative structure as revealed by a four-fold increase in the quantum yield as compared to truxene. The derivatives of this material have great potential in optoelectronic devices and in organic photovoltaics. This proposed new synthetic method can be used to introduce other heteroatoms into the truxene system. [ABSTRACT FROM AUTHOR]

In this paper, a novel methodology is introduced for the synthesis of novel 5-methyl-8H-isoquinolino[1,2-b]quinazolin-8-one derivatives based on an efficient immobilized palladium catalyzed intramolecular carbon–carbon bond formation. The novel catalyst is fabricated by immobilization of Pd on phosphinite polyethyleneimine functionalized Fe3O4@SiO2 core–shell nanoparticles (denoted as Pd@OPPh2–PEI–mSiO2 NPs). In this catalyst, PEI moieties act as both a water dispersant and base in the reaction. In the key step, 3-allyl-2-(2-bromophenyl)-2,3-dihydroquinazolin-4(1H)-ones (3a–i) were synthesized via a cyclization reaction between N-allyl-2-aminobenzamides and 2-bromobenzaldehyde. The latter obtained materials then underwent an intramolecular carbon–carbon bond formation in the presence of the Pd@Ph2PO–PEI–mSiO2 catalyst to give 5-methyl-13,13a-dihydro-8H-isoquinolino[1,2-b]quinazolin-8-ones (4a–i). [ABSTRACT FROM AUTHOR]