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Compared with the ever-growing list of nonprochiral nucleophiles in Ir-catalyzed asymmetric allylic substitution reactions, prochiral nucleophiles are less studied. We present a new prochiral nucleophile, namely, deconjugated butyrolactam, for Ir-catalyzed asymmetric allylic alkylation (AAA). This reaction provides access to I±-allyl deconjugated butyrolactams with a moderate to good dr and an excellent er. This is the first AAA reaction of deconjugated butyrolactams. Allyl transposition through Cope rearrangement appears to proceed stereospecifically to form I³-allyl conjugated butyrolactams. © 2021 American Chemical Society.

The first catalytic enantioselective Fischer indolization of prochiral diketones containing enantiotopic carbonyl groups is developed and shown to proceed through dynamic kinetic resolution (DKR). Catalyzed by the combination of a spirocyclic chiral phosphoric acid and ZnCl2 (Lewis acid assisted Bronsted acid), this direct approach combines 2,2-disubstituted cyclopentane-1,3-diones with N-protected phenylhydrazines to furnish cyclopenta[b]indole derivatives containing an all-carbon quaternary stereocenter with good to excellent enantioselectivities.

The first iridium-catalyzed enantioselective olefinic C(sp2)–H allylic alkylation is developed in cooperation with Lewis base catalysis. This reaction, catalyzed by cinchonidine and an in situ generated cyclometalated Ir(i)/phosphoramidite complex, makes use of the latent enolate character of an α,β-unsaturated carbonyl compound, namely coumalate ester, to introduce an allyl group at its α-position in a branched-selective manner in moderate to good yield with good to excellent enantioselectivities (up to 98 : 2 er)., The first iridium-catalyzed enantioselective allylic alkylation of an olefinic C(sp2)–H bond – that of an α,β-unsaturated carbonyl compound, is developed in cooperation with Lewis base catalysis.

Atomically thin sheets of two-dimensional (2D) transition metal dichalcogenides (TMDs) have attracted interest as high capacity electrode materials for electrochemical energy storage devices owing to their unique properties (high surface area, high strength and modulus, faster ion diffusion, and so on), which arise from their layered morphology and diversified chemistry. Nevertheless, low electronic conductivity, poor cycling stability, large structural changes during metal-ion insertion/extraction along with high cost of manufacture are challenges that require further research in order for TMDs to find use in commercial batteries and supercapacitors. Here, a systematic review of cutting-edge research focused on TMD materials beyond the widely studied molybdenum disulfide or MoS2 electrode is reported. Accordingly, a critical overview of the recent progress concerning synthesis methods, physicochemical and electrochemical properties is given. Trends and opportunities that may contribute to state-of-the-art research are also discussed.

Enantioselective allenylic alkylation reactions of unstabilized enolates have never been reported. We now present a unified fragment-coupling strategy for the first enantioselective synthesis of α-allenylic amides and ketones through allenyl-ic alkylation of vinyl azides. In these chemodivergent reactions, cooperatively catalyzed by Ir(I)/(phosphoramidite,olefin) complex and Sc(OTf)3, vinyl azides act as the surrogate for both amide enolates and ketone enolates. The desiccant (molecular sieves) plays a crucial role in controlling the chemodivergency of this enantioconvergent and regioselective reaction: Under otherwise identical reaction conditions, the presence of the desiccant led to α-allenylic amides while its absence resulted in α-allenylic ketones from the same substrate combinations. Utilizing race-mic allenylic alcohols as the alkylating agent, the overall process represents a dynamic kinetic asymmetric transformation (DyKAT), where both α-allenylic amides and ketones are formed with the same absolute configuration generally with outstanding enantioselectivity. To the best of our knowledge, this is the first example of the use of vinyl azide as the ketone enolate surrogate in an enantioselective transformation.

Experimental 13C kinetic isotope effects (KIEs) and DFT calculations are used to evaluate the mecha-nism and the origin of enantioselectivity in the C(sp2)‒H alkylative desymmetrization of cyclopentene-1,3-diones using nitroalkanes as the alkylating agent. An unusual combination of an inverse (~0.980) and a normal (~1.030) KIE is observed on the bond-forming carbon atoms of the cyclopentene-1,3-dione and nitroalkane, respectively. These data provide strong support for a mechanism involving reversible carbon-carbon bond-formation followed by rate- and enantioselectivity-determining nitro-group elimination. The theoretical free energy profile and predicted KIEs indicate that this elimination event occurs via an E1cB pathway. The origin of remote stereocontrol is evaluated by distortion-interaction and SAPT0 analyses of the enantiomeric E1cB transition states.

Polymer-derived-ceramics (PDCs) and PDC-based fibers are being studied as potential high capacity electrode materials for electrochemical energy storage applications. Among these, silicon oxycarbide (SiOC) has shown most promise, especially as electrodes in lithium ion batteries (LIB). The study of PDCs for supercapacitor electrodes is, however, very limited. This work investigates the fabrication of SiOC-based PDC fiber mats via electrospinning and pyrolysis of three commercial pre-ceramic silicone resins (MK, H44, RSN) of varying composition, and their use as supercapacitor and LIB electrodes. Electron microscopy, Fourier transform infrared spectroscopy and Raman spectroscopy was performed to study the effect of precursor chemical composition, pyrolysis time and temperature on the morphology, polymer to ceramic transformation and free carbon content. As supercapacitor electrodes, the H44 (a methyl-siloxane) derived SiOC showed the best performance with maximum specific capacitance of 50 F g-1 with capacity retention of ~100% after 2000 cycles. Similarly, as LIB electrodes, H44 derived SiOC fiber mat showed highest reversible capacity of 578 mAh g-1 at a current density of 50 mA g-1.

The first catalytic enantioselective Michael addition of deconjugated butyrolactams to N-arylmaleimides is developed with the help of a bifunctional tertiary aminosquaramide catalyst. Unlike the widely explored and structurally related vinylogous nucleophile – deconjugated butenolides, deconjugated butyrolactams are found to be exclusively α-selective. The resulting highly substituted and densely functionalized products, bearing contiguous all-carbon quaternary and tertiary stereocenters, are formed in good yields with moderate diastereoselectivity and good to excellent enantioselectivity (up to 99:1 er).

We introduce a novel chemical preintercalation based synthesis technique based on hydrogen peroxide induced sol-gel process to obtain alkali ion containing ternary layered titanates (MTO, where M = Li, Na, K). Synthesis parameters leading to the formation of single-phase materials with homogeneous elemental distribution are reported for each of the preintercalated ion. Our analyses indicate that the interlayer spacing in the structure of the layered titanates increases with the increase of the radius of the hydrated preintercalated ion. Scanning and transmission electron microscopy imaging revealed morphological diversity: the LTO phase crystallized as nanoplates assembled in “peony-like” spherical agglomerates while NTO and KTO particles exhibited one-dimensional nanobelt or wire-like morphology, with the KTO nanobelts being shorter and more aggregated than the NTO nanobelts. Structural refinement corroborated by electron diffraction and high-resolution transmission electron microscopy revealed that the structure of the LTO phase is built by stacking Ti-O layers containing a single straight layer of connected TiO(6) octahedra. The layers in NTO and KTO structures form differently and consist of double Ti-O layers with ragged arrangement of units built by TiO(6) octahedra with two titanium rows. The NTO electrodes exhibited the highest electrochemical performance in cells with aqueous 1 M Na(2)SO(4) electrolyte, followed by the KTO electrodes and then LTO electrodes, and this trend is maintained at various scan rates. The established relationships between the structure and electrochemical performance reveal that, in addition to interlayer distance and chemistry of the interlayer region, the structure of the layers can play an important role in charge storage properties of layered oxide electrodes. The double Ti-O layers in the structure of NTO and KTO phases provide a larger number of redox centers which could contribute to the superior electrochemical performance as compared to the LTO electrodes. Our findings indicate that layered materials containing double transition metal oxide layers are promising candidates for exfoliation and assembly with electronically conductive layers with the aim to create 2D heterostructures with high electrochemical performance.

Among the unstabilized enolates used as nucleophiles in iridium-catalyzed asymmetric allylic alkylation reactions, amide enolates are the least explored. Vinyl azides are now employed as amide enolate surrogates in Ir-catalyzed asymmetric allylic alkylation with branched allylic alcohols as the allylic electrophile. Competing reaction pathways are suppressed through the systematic tuning of the steric and electronic properties of vinyl azide to effect the α-allylic alkylation of secondary acetamides with high atom economy, exclusive branched selectivity, and mostly excellent enantioselectivity.

The wide abundance of γ-lactones in natural products and bioactive targets calls for suitable building blocks for their enantioselective synthesis. β,γ-Unsaturated γ-butenolides, commonly known as deconjugated butenolides, owing to their easy accessibility and highly reactive nature, have emerged as the synthon of choice during the past decade for the enantioselective synthesis of γ-lactones. Their compatibility under organocatalytic, metal-catalyzed as well as cooperative catalytic conditions has resulted in numerous enantioselective transformations involving deconjugated butenolides. These reactions not only led to enantioenriched γ-lactones, but also various other heterocycles and acyclic compounds through ring-opening and fragmentation of the parent butenolide ring. The purpose of this review is to provide a comprehensive treatise on the catalytic asymmetric reactions of deconjugated butenolides reported so far. This aspect is presented alongside the preparation and reactivity comparison of deconjugated butenolides with other competing synthons of γ-lactones. Limitations of the existing protocols and the possible scope for future development are also discussed.

Summarization: There is an increasing trend of developing various low-cost grafted natural amino polysaccharides for the biosorptive removal of noxious dye effluents like Malachite green (MG) and anionic Reactive Red–195 (RR-195) dyes from aqueous solution. Chemically cross-linked chitosan microsphere (CTS-HMP), a promising non-toxic biosorbent possessing high charge density and thermal stability was prepared by using hexametaphosphate as ionic cross-linker. Batch biosorption experiments were carried out under different temperatures (298, 308 and 318 K), pH (2.0–10.0), initial concentrations (25–250 mg L−1), adsorbent dosage (0.01–0.1 g) and contact times (0–180 min) to understand the optimum experimental conditions and simultaneously evaluate the adsorption isotherms and kinetics of CTS-HMP. Biosorption equilibrium was established in 120 and 60 min for MG and RR-195 removal process. The pseudo-equilibrium process was best described by the pseudo-second-order kinetic (R2 ≥ 0.98), Freundlich and Temkin isotherm model (R2 ≥ 0.90). The removal rate of MG and RR-195 gradually increased (69.40 and 148 mg g−1) at 250 mg L−1 of initial concentration till 100 and 50 min of contact period in a single contaminant system, though the removal efficiency of acid dye was ~2 times higher compared to basic dye under optimum conditions (p < 0.05; t-test). Thermodynamic parameters indicated exothermic (MG) and endothermic (RR-195) nature of spontaneous dye removal. The activation energy of sorption (Ea) was

Among the unstabilized enolates used as nucleophile in iridium-catalyzed asymmetric allylic alkylation reactions, amide enolates are least explored. Vinyl azides are now employed as amide enolate surrogate for the first time in Ir-catalyzed asymmetric allylic alkylation with branched allylic alcohols as the allylic electrophile. Competing reaction pathways are suppressed through systematic tuning of steric and electronic properties of vinyl azide to effect α-allylic alkylation of secondary acetamides with high atom-economy, exclusive branched selectivity and moderate to excellent enantioselectivity.

There is a dire necessity of developing low cost waste water treatment systems, for the efficient removal of noxious heavy metals (and metalloids) such as Arsenic (As) and Cadmium (Cd). Magnetic biopolymer (CABs-MO) was synthesized by the entrapment of nanocrystalline MnO2 in the polymeric microcapsules of calcium alginate (CABs). Batch experiments were conducted under constant pH (6.5), temperature (25OC), different initial concentrations (30-300 mg L-1) and contact times (0-48 h) to study the adsorption isotherms and removal kinetics of pristine (CABs) and hybrid biopolymer (CABs-MO) for the removal of As and Cd. The pseudo-equilibrium process was mathematically well explained by the pseudo-second-order kinetic (R2 ≥ 0.99) and Langmuir isotherm model (R2 ≥ 0.99) with the highest monolayer sorption capacity of 63.6 mg g-1 for Cd on CABs-MO. The As removal rate was maximum up to 6.5 mg g-1 after 12 h of contact period in a single contaminant system than in the mixed contaminant (As + Cd) system (0.8 mg g-1), though the effect was non-significant for Cd (p

Arsenic (As), a geogenic and extremely toxic metalloid can jeopardize terrestrial and aquatic ecosystems through environmental partitioning in natural soil-water compartment, geothermal and marine environments. Although, many researchers have investigated the decontamination potential of different mesoporous engineered bio sorbents for a suite of contaminants, still the removal efficiency of various pyrolyzed agricultural residues needs special attention. In the present study, rice straw derived biochar (RSBC) produced from slow pyrolysis process at 600 °C was used to remove As (V) from aqueous medium. Batch experiments were conducted at room temperature (25 ± 2 °C) under different initial concentrations (10, 30, 50, 100 μg L-1), adsorbent dosages (0.5-5 μg L-1), pH (4.0-10.0) and contact times (0-180 min). The adsorption equilibrium was established in 120 min. Adsorption process mainly followed pseudo-second order kinetics (R2 ≥ 0.96) and Langmuir isotherm models (R2 ≥ 0.99), and the monolayer sorption capacity of 25.6 μg g-1 for As (V) on RSBC was achieved. Among the different adsorbent dosages and initial concentrations used in the present study, 0.2 g L-1 (14.8 μg g-1) and 100 μg L-1 (13.1 μg g-1) were selected as an optimum parameters. A comparative analysis of RSBC with other pyrolyzed waste materials revealed that RSBC had comparable adsorption ability (per unit area). These acidic groups are responsible for the electron exchange (electrostatic attraction, ion-exchange, π-π/n-πinteractions) with the anionic arsenate, which facilitates optimum removal (>60%) at 7

The first catalytic enantioselective direct aldol reaction of 3-acetylcoumarins to pyrazole-4,5-diones is reported and shown to proceed through noncovalent substrate activation by a quinine-derived bifunctional tertiary amino-amide as the catalyst. The densely functionalized products, consisting of an oxygen-containing quaternary stereocenter and bearing two biologically relevant heterocycles, are generally obtained in high yields with moderate to excellent enantioselectivities.

Non-Li metal-ion rechargeable battery systems, e.g., Na-, K-, Mg-, and Ca-ion systems, are at the brink of playing a major role for sustainable energy and grid storage, in part owing to their signi...

Two-dimensional (2D) materials have elicited considerable interest in the past decade due to a diverse array of novel properties ranging from high surface to mass ratios, a wide range of band gaps (insulating boron nitride (BN) to semiconducting transition metal dichalcogenides), high mechanical strength and chemical stability. Given the superior chemo-thermo-mechanical properties, 2D materials may provide transformative solution to a familiar yet persistent problem of significant socio-economic burden: the corrosion of stainless steel (SS). With this broader perspective, we investigate corrosion resistance properties of SS-coated with 2D nanomaterials; molybdenum disulfide (MoS2), BN, bulk graphite in 3.5 wt% aqueous NaCl solution. The nanosheets were prepared by a novel liquid phase exfoliation technique and the coatings were made by a paint brush to achieve uniformity. Open circuit potential (OCP) and potentiodynamic plots indicate the best corrosion resistance is provided by the MoS2coatings. Superior performance of the coating is attributed to low electronic conductivity, large flake size and uniform coverage of SS substrate, which probably impeded the corrosive ions from the solution from diffusing through the coating.

Nucleophilic reactivity of deconjugated butyrolactams has been demonstrated for enantioselective Michael additions to α,β-unsaturated aldehydes and ketones. These reactions are catalyzed by diphenylprolinol silyl ether and trans-1,2-diaminocyclohexane-derived bifunctional primary aminothiourea, respectively, producing the Michael adducts with moderate diastereoselectivities and good to excellent enantioselectivities (up to 99:1 er). Unlike in the case of structurally related deconjugated butenolides where vinylogous addition is prevalent, an exclusive α-addition is observed for deconjugated butyrolactams.

The first catalytic enantioselective vinylogous nucleophilic addition to pyrazole-4,5-diones is reported. Using quinine-derived bifunctional tertiary amino-amide as the catalyst, this direct aldol reaction of allyl ketones is shown to proceed exclusively in γ- and E-selective manner to generate pyrazolone derivatives, bearing an oxygen-containing quaternary stereogenic center, in good yields with moderate to high enantioselectivities (up to 97:3 er).

We synthesized CuAlS2/ZnS quantum dots (QDs) composed of biocompatible, earth abundant elements that can reduce salts of carbon dioxide under visible light. The use of an asymmetric morphology at a type-II CuAlS2/ZnS heterointerface balances multiple requirements of a photoredox agent by providing a low optical bandgap (~1.5 eV), a large optical cross section (>10-16 cm2 above 1.8 eV), spatial proximity of both semiconductor components to the surface as well as photochemical stability. CuAlS2/ZnS QDs thus have an unprecedented photochemical activity in terms of reducing carbon dioxide in the form of aqueous sodium bicarbonate under visible light, without the need of a co-catalyst, promoter or a sacrificial reagent while maintaining large turnover numbers in excess of 7x104 per QD. Devices based on these QDs exhibit energy conversion efficiencies as high as 20.2 ± 0.2%. These observations are rationalized through our spectroscopic studies that show a short 550 fs electron dwell times in these structures. T...

General visible light-mediated aerobic oxidation of boronic acids is unveiled using CdSe nanocrystal quantum dots (QDs) as the photoredox catalyst. This protocol requires mild reaction conditions and low catalyst loading (down to 10 ppm), and tolerates various functional groups. The resulting phenols and aliphatic alcohols are produced in good to high yield with turnover numbers as high as >62000. The reaction mechanism is probed using ultrafast transient absorption and luminescence spectroscopy. The existence of a rapid 350 ps initial electron transfer followed by a hole transfer is demonstrated.

Arsenic (As), a geogenic legacy pollutant can be present in environmental matrices (water, soil, plants, or animal) in two redox states (As(III) or As(V)). In the present study, charged mono- and di-amino functionalized triethoxy and methoxyorganosilane (TT1 and TT2- 1% and 5%) were impregnated with quartz sand particles for the treatment of As polluted water. Spectroscopic characterization of organosilane treated sand (STS) indicated the co-existence of minerals (Mg, Mn, Ti), amide, and amidoalkyl groups, which implies the suitability of silanized materials as a metal(loids) immobilization agent from water. Changes in peaks were observed after As sorption in Fourier thermal infrared and EDS images indicating the involvement of chemisorption. Batch sorption studies were performed with the optimized experimental parameters, where an increased removal (>20% for TT2-1% and >60% for TT1-1%) of As was observed with sorbate concentration (50 µg L-1), temp. (25 ± 2 oC) and sorbent dosages (of 10 g L-1) at 120 min contact time. Among the different adsorbent dosages, 10 g L-1 of both TT1 and TT2 was selected as an optimum dosage (maximum adsorption capacity ≈ 2.91 μg g-1). The sorption model parameters suggested the possibility of chemisorption, charge/ion-dipole interaction for the removal of arsenate.

The first catalytic enantioselective synthesis of 5,6-dihydro-4H-1,2-oxazines bearing an oxygen-containing quaternary stereogenic center has been developed through iodoetherification of γ,δ-unsaturated oximes. This operationally straightforward reaction is catalyzed by Cinchona alkaloids-based bifunctional tertiary aminothiourea derivatives and furnishes the products generally in good to excellent yields and with moderate to high enantioselectivities (up to 97:3 er).

The first iridium-catalyzed enantioselective vinylogous allylic alkylation of coumarins is presented. Using easily accessible linear allylic carbonates as the allylic electrophile, this reaction installs unfunctionalized allyl groups at the γ-position of 4-methylcoumarins in an exclusively branched-selective manner generally in high yields with an excellent level of enantioselectivity (up to 99 : 1 er).

An unprecedented, organocatalytic enantioselective vinylogous γ-allylic alkylation of 4-methylcoumarins has been developed. Using allylic carbonates as the allyl source, this reaction is catalyzed by Lewis basic dimeric Cinchona alkaloid (QD)2PHAL and proceeds exclusively in a γ- and branched-selective manner to produce densely functionalized coumarin derivatives generally in good yields with good to high enantioselectivities (up to 97:3 er).

A facile, scalable, and solution-based technique is used to fabricate Al and Ni-doped (LiAl0.1Mn1.9O4 and LiAl0.1Ni0.1Mn1.8O4) microspheres of lithium manganese oxide (LMO) spinels for use as reversible cathode materials for lithium ion batteries (LIBs). The spheres of the two samples exhibit different porosities. Cells with these LMO-based cathodes are then cycled between 4.5 V and 2 V to study their stabilities while simultaneously being subjected to the undesirable Jahn-Teller distortion that occurs around the ~3 V regime. The LiAl0.1Mn1.9O4 (LAMO) and the LiAl0.1Ni0.1Mn1.8O4 (LANMO) cells exhibit comparable open circuit voltages (OCV) of 2.94 V and 2.97 V, respectively. During cell cycling, the LAMO cell exhibits a maximum specific capacity of 122.51 mAh g−1 with a capacity fade of 65.35% after 75 cycles. The LiAl0.1Ni0.1Mn1.8O4 (LAMO) sample fares better and exhibits a maximum of 140.49 mAh g−1 and a capacity drop of 52.59%. Detailed structural studies indicate that Ni doping and the greater ...

With the rising demand for abundant and safer energy storage, rechargeable nonlithium ion electrochemical systems are being increasingly considered as alternatives to lithium-ion battery (LIB) systems. However, as these alternative ions, owing to their large sizes, have their own kinetic and structural, upgraded electrode architectures become an important necessity. It is here that 2D materials, due to the large number of favorable properties such as high surface area, elevated electrical and thermal conductivities, and enhanced chemical and mechanical stability are deemed to play a very important role. Also, novel fabrication techniques have been developed which aim to greatly tailor and take advantage of the variety of fascinating morphology and layered structures that 2D materials provide. It is the also expected that a combination of 2D materials, as a hybrid, will further enhance the overall electrochemical performance. Recent studies along those lines have demonstrated, synergistic effects between graphene and other 2D materials including transition metal dichalcogenides, MXenes, and phosphorene based anodes have been observed. In this chapter, applications and performances of graphene-based 2D hybrid anodes for advanced nonlithium batteries (sodium-ion, potassium-ion, and magnesium-ion battery systems) is presented.

Growing concerns regarding the safety, flammability and hazards posed by Li-ion systems have led to research on alternative rechargeable metal-ion electrochemical storage technologies. Among the most notable of these are Na-ion supercapacitors and batteries, motivated, in part, by the similar electrochemistry of Li and Na ions. However, sodium ion batteries (SIBs) come with their own set of issues, especially the large size of the Na + ion, its relatively sluggish kinetics and low energy densities. This makes the development of novel materials and appropriate electrode architecture of absolute significance. Transition metal dichalcogenides (TMDs) have attracted a lot of attention in this regard due to their relative ease of exfoliation, diverse morphologies and architectures with superior electronic properties. Here, we study the electrochemical performance of Mo-based two-dimensional (2D) layered TMDs (e.g. MoS 2 , MoSe 2 and MoTe 2 ), exfoliated in a superacid, for battery and supercapacitor applications. The exfoliated TMD flakes were interfaced with reduced graphene oxide (rGO) to be used as composite electrodes. Electron microscopy, elemental mapping and Raman spectra were used to analyse the exfoliated material and confirm the formation of 2D TMD/rGO layer morphology. For supercapacitor applications in aqueous electrolyte, the sulfide-based TMD (MoS 2 ) exhibited the best performance, providing an areal capacitance of 60.25 mF cm −2 . For SIB applications, TMD electrodes exhibited significantly higher charge capacities than the neat rGO electrode. The initial desodiation capacities for the composite electrodes are 468.84 mAh g −1 (1687.82 C g −1 ), 399.10 mAh g −1 (1436.76 C g −1 ) and 387.36 mAh g −1 (1394.49 C g −1 ) for MoS 2 , MoSe 2 and MoTe 2 , respectively. Also, the MoS 2 and MoSe 2 composite electrodes provided a coulombic efficiency of near 100 % after a few initial cycles.

The first enantioselective vinylogous allylic alkylation of 4-methylquinolones has been developed. This iridium-catalyzed reaction introduces an allyl group at the γ-position of 4-methyl-2-quinolones with exclusive branched selectivity and an excellent level of enantioselectivity. This in turn allows for the enantioselective synthesis of γ-allylquinolines and related nitrogenous heterocycles. This is the first application of 4-methylquinolones in an enantioselective transformation.

Sodium ion batteries (SIBs) are being billed as an economical and environmental alternative to lithium ion batteries (LIBs), especially for medium and large-scale stationery and grid storage. However, SIBs suffer from lower capacities, energy density and cycle life performance. Therefore, in order to be more efficient and feasible, novel high-performance electrodes for SIBs need to be developed and researched. This review aims to provide an exhaustive discussion about the state-of-the-art in novel high-performance anodes and cathodes being currently analyzed, and the variety of advantages they demonstrate in various critically important parameters, such as electronic conductivity, structural stability, cycle life, and reversibility.

The first enantioselective decarboxylative [4 + 2]-annulation of ethynyl benzoxazinanones with azlactones has been developed under cooperative copper and bifunctional tertiary aminourea catalysis. This direct and modular approach combines dipolar copper-allenylidene intermediates with azlactone enolates and allows for the synthesis of α-quaternary α-acylaminoamides as a single diastereomer generally in high yields with good to excellent enantioselectivities (up to 99:1 er).

Biochar was produced from wheat straw (Triticum aestivum), rice straw (Oryza sativa), and kitchen waste at varying pyrolysis temperatures (300°C-700 °C). The biochars were screened depending on their production and physicochemical properties for the adsorptive removal of arsenic (As). The morphological analysis by Field emission scanning electron microscope revealed a porous biochar surface. Spectroscopic characterization of biochars indicated the co-existence of minerals, carboxyl, carbonyl, amide, and hydroxyl groups, which implies the suitability of biochar to immobilize metal (loid)s from soils. Changes in peaks were observed in Fourier-transform infrared and X-ray diffraction images after As sorption indicating the involvement of chemisorption. The thermogravimetric analysis and a low H/C value derived from the CHNS analyzer confirmed the high stability of biochar. The BET analysis was used to estimate the surface areas of wheat straw (15.8 m

The Schiff base ligand (L1) showing large fluorescence intensity in an aqueous medium owing to a ground state intramolecular proton transfer (GSIPT) reaction was utilized in a complexation process to generate a highly stable non-fluorescent Cu(II)/L1 (1) in its “turn-off” mode. The 3:2 Cu(II)/L1 stoichiometric complex (1), isolated in the solid form, exhibited a cysteine (Cys)-induced “turn-on” fluorescence response with a unique time-dependent intensity variation. Unlike other biothiols, the partially deprotonated –SH moiety in Cys is highly susceptible for participating in an ionic interaction with Cu(II)-centres in 1 at a physiological pH of ∼7.4, followed by reduction to Cu(I), and then a subsequent demetallation, resulting in a large increment of the fluorescence intensity for free fluorophoric L1, which persists for about 4 –13 min owing to an unexpected stability of the Cu(I) ions. After Cys consumption, Cu(I) ions in aqueous solution rapidly oxidize to participate further in complexation with the existing free L1. The resulting complex may again be susceptible to Cys-induced abovementioned decomplexation followed by complexation for at least four different external Cys additions in four successive cyclic pathways. This multiple Cys sensing behaviour has been exploited to recognize the existence of Cys in multicellular Caenorhabditis elegans (C. elegans).

A formal umpolung strategy is presented for the enantioselective installation of an alkenyl group with a terminal double bond at a tertiary center. This one-pot two-step sequence relies on the unique features of the nitro group, which after inverting the polarity of the alkenylating agent toward the desired bond formation, itself serves as a leaving group. The application of this protocol to cyclic β-ketoesters results in densely functionalized products, bearing an all-carbon quaternary stereocenter including an alkenyl substituent with a terminal double bond, in high yields with excellent enantioselectivities.

The enantioselective Diels-Alder (DA) reaction with monosubstituted p-benzoquinones is an unmet challenge. A new approach for the enantioselective synthesis of monosubstituted quinone-DA adducts is presented based on C(sp2)-H alkylative desymmetrization of meso-DA adducts. Catalyzed by a tertiary amino-thiourea derivative, this reaction utilizes nitroalkanes as the alkylating agents and generates densely functionalized products bearing at least four contiguous stereogenic centers remote from the reaction site with excellent enantioselectivities.

An enantioselective formal C(sp2)−H vinylation of prochiral 2,2-disubstituted cyclopentene-1,3-dione is presented. This vinylative desymmetrization is realized by using a two-step procedure that consists of a catalytic enantioselective vinylogous Michael addition of deconjugated butenolides to cyclopentene-1,3-dione and a base-mediated decarboxylation. The overall process utilizes deconjugated butenolides as the source of the highly substituted vinyl unit. Five-membered carbocycles containing a remote all-carbon quaternary stereogenic center are obtained in good yields and with good to high enantioselectivities.

Antineoplastics (anticancer agents) i.e. alkylating and non-alkylating agents, topoisomerase inhibitors etc. are classified as the contaminants of emerging concern due to growing concern about environmental health degradation. Such cytostatic agents contain a suit of functional groups (i.e. folic acid/purine/pyrimidine/nitrogen analogues), which render their complex chemistry and determine partitioning in the aquatic systems. A systematic review of the recent literature published between 2009 and 2020 has been presented to validate the hypothesis that the environmental fate, distribution, and removal aspects of chemotherapeutic agents depend largely on the structural orientation, environmental (and genetic) factors, and degree of ionization. The key knowledge gaps on the current challenges and opportunities of research trends of cytostatic drugs (and their derivatives) in the environment have been identified and critically discussed. This review provides an overview of risk assessment of pyrimidine antimetabolites and topoisomerase inhibitors, which is need of the hour considering their increasing consumption and state-of-the-art analytical detection. The main focus of the review is that a cocktail mixture of tamoxifen, 5-fluorouracil and other active metabolites of polar, water soluble antineoplastic agents may have the accumulation effect on the aquatic species. They can spread drug resistance via their interaction with some kinases.

Correction for ‘Iridium-catalyzed enantioselective olefinic C(sp2)–H allylic alkylation’ by Rahul Sarkar et al., Chem. Sci., 2021, DOI: 10.1039/d0sc06208a.

Geopolymers are the inorganic polymers containing aluminosilicate materials in their backbone and are produced from geopolymerization process at ambient or controlled temperature involving alkali activators and balanced proportion of solid silica/aluminium precursor materials. Geopolymeric binders have excellent surface morphology, mechanical strength, and building material properties depending on different origin of sources facilitated by hydrothermal synthesis and solidification/stabilization reactions of inorganic polymers. We present a systematic review of the literature published between 1991 and 2020 to critically analyze the structural chemistry, synthesis and environmental applications of geopolymers and have thoroughly discussed the relevant state-of-the art experimental results to have more insight on the metal immobilization potential of geopolymers. Our aim is also to critically assess the different isotherm and kinetic models to illustrate the different mechanisms for the effective waste management strategies of different geopolymer binders by spontaneous, endothermic and entropy driven thermodynamic metal entrapment process. Therefore, the present review bridges the knowledge gap to throw light on the source of various materials commonly applied to the material/bio based synthesis of geopolymer materials which have direct impact on the geopolymerization process. Such types of approaches trigger the environmentalists and policymakers in the development of a conceptual framework on green sustainable aluminosilicate based adsorbents, which facilitate better waste management by physical entrapment, chemical bonding and/or ligand exchange reactions.

There is an increasing trend of developing various low-cost biogenic sorbents for the efficient and economical removal of noxious metals . Curry leaf powder (CLP), a promising non-toxic biosorbent containing several bioactive compounds was prepared by the pulverization of the dried leaves for the effective removal of Lead (Pb) and Cadmium (Cd). Various batch sorption experiments were carried out under constant temperature (25 °C), different pH (4.5–10.5), initial concentrations (50–200 mg L−1), adsorbent dosages (0.10–0.40 g) and contact times (0–60 min) to understand the optimum experimental conditions and simultaneously evaluate the adsorption isotherms and removal kinetics of CLP. Adsorption equilibrium was established in less than an hour interval (50 min). The pseudo-equilibrium process was best described by the pseudo-second-order kinetic (R2 ≥ 0.99), Freundlich and Langmuir isotherm model (R2 ≥ 0.94). The removal rate of Pb and Cd gradually increased (15.7 and 12.7 mg g−1 for Pb and Cd) at 100 mg L−1 of initial concentration till 60 min of contact period in a single contaminant system, the effect was non-significant for multiple adsorbent dosage systems (p > 0.05; t-test) though. The regeneration potential of the exhausted biosorbent was excellent upto 5 cycles with the better efficiency observed for Pb. The obtained results explicitly validated the probable utilization of CLP as a promising green adsorbent for metal removal . Future study may highlight the decontamination aspects of emerging contaminants with such green bio sorbents in large scale as well as mimicing the stomach conditions.

Intensive research effort is currently focused on the development of efficient, reliable, and environmentally safe electrochemical energy storage systems due to the ever-increasing global energy storage demand. Li ion battery systems have been used as the primary energy storage device over the last three decades. However, low abundance and uneven distribution of lithium and cobalt in the earth crust and the associated cost of these materials, have resulted in a concerted effort to develop beyond lithium electrochemical storage systems. In the case of non-Li ion rechargeable systems, the development of electrode materials is a significant challenge, considering the larger ionic size of the metal-ions and slower kinetics. Two-dimensional (2D) materials, such as graphene, transition metal dichalcogenides, MXenes and phosphorene, have garnered significant attention recently due to their multi-faceted advantageous properties: large surface areas, high electrical and thermal conductivity, mechanical strength, etc. Consequently, the study of 2D materials as negative electrodes is of notable importance as emerging non-Li battery systems continue to generate increasing attention. Among these interesting materials, graphene has already been extensively studied and reviewed, hence this report focuses on 2D materials beyond graphene for emerging non-Li systems. We provide a comparative analysis of 2D material chemistry, structure, and performance parameters as anode materials in rechargeable batteries and supercapacitors.

Biopurification systems, such as biofilters, are biotechnological tools to prevent point sources of pesticide pollution stemming from on-farm operations. For the purification processes pesticide sorption and mineralization and/or dissipation are essential and both largely depend on the type of filling materials and the pesticide in use. In this paper the mineralization and dissipation of three contrasting (14)C-labeled pesticides (bentazone, boscalid, and pyrimethanil) were investigated in laboratory incubation experiments using sandy soil, biochar produced from Pine woodchips, and/or digestate obtained from anaerobic digestion process using maize silage, chicken manure, beef and pig urine as feedstock. The results indicate that the addition of digestate increased pesticide mineralization, whereby the mineralization was not proportional to the digestate loads in the mixture, indicating a saturation effect in the turnover rate of pesticides. This effect was in correlation with the amount of water extractable DOC, obtained from the digestate based mixtures. Mixing biochar into the soil generally reduced total mineralization and led to larger sorption/sequestration of the pesticides, resulting in faster decrease of the extractable fraction. Also the addition of biochar to the soil/digestate mixtures reduced mineralization compared to the digestate alone mixture but mineralization rates were still higher as for the biochar/soil alone. In consequence, the addition of biochar to the soil generally decreased pesticide dissipation times and larger amounts of biochar led to high amounts of non-extractable residues of pesticide in the substrates. Among the mixtures tested, a mixture of digestate (5%) and biochar (5%) gave optimal results with respect to mineralization and simultaneous sorption for all three pesticides.

Cascade Michael/cyclization reactions between 3-isothiocyanato oxindoles and exocyclic α,β-unsaturated ketones are shown to proceed efficiently in the presence of a quinine-derived tertiary amino-squaramide catalyst and furnish 3,2'-pyrrolidinyl bispirooxindoles containing two spiro-quaternary and three contiguous stereocenters as a single diastereomer with excellent enantioselectivities (up to 99 : 1 er).