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AgBiO3 is reported for the exclusive oxidation of Am3+ → AmO2+ at near-neutral pH conditions. Literature methods of AmO2+ generation are generally two-step processes; i.e., Am3+ → AmO22+ oxidation followed by AmO22+ → AmO2+ reduction. These methods for Am3+ → AmO2+ oxidation use high temperatures (80–100 °C) and/or several reagents, causing the in situ presence of the AmO2+-complex rather than the AmO2+aq ions. This not only interferes with the much-needed Am–Cm selectivity but also limits the use of AmO2+aq in any other experimental study. The single-step Am3+ → AmO2+ oxidation in the present work using AgBiO3 is done at 25 °C in a non-complexing medium at pH ∼4, making it a first-of-its-kind report. Am–Eu and Am–Cm separation in a single contact, with a separation factor >104, was achieved using the present method, which is unprecedented among aqueous feed solutions. The AmO2+ generated using the present method under non-complexing pH conditions makes it also suitable for exploring the fundamental chemistry of the higher valent americyl ion. A complexation study using the thus-generated AmO2+ ion with acetate ion supports the concept. [ABSTRACT FROM AUTHOR]

Electrochemical reduction of carbon dioxide (CO2) or carbon monoxide (CO) to valuable multi-carbon (C2+) products like acetate is a promising approach for a sustainable energy economy. However, it is still challenging to achieve high activity and selectivity for acetate production, especially in neutral electrolytes. Herein, a bioinspired hemin/Cu hybrid catalyst was developed to enhance the surface *CO coverage for highly efficient electroreduction of CO to acetate fuels. The hemin/Cu electrocatalyst exhibits a remarkable faradaic efficiency of 45.2% for CO-to-acetate electroreduction and a high acetate partial current density of 152.3 mA cm−2. Furthermore, the developed hybrid catalyst can operate stably at 200 mA cm−2 for 14.6 hours, producing concentrated acetate aqueous solutions (0.235 M, 2.1 wt%). The results of in situ Raman spectroscopy and theoretical calculations proved that the Fe–N4 structure of hemin could enhance the CO adsorption and enrich the local concentration of CO, thereby improving C–C coupling for acetate production. In addition, compared to the unmodified Cu catalysts, the Cu catalysts functionalized with cobalt phthalocyanine with a Co–N4 structure also exhibit improved acetate performance, proving the universality of this bioinspired molecule-enhanced strategy. This work paves a new way to designing bioinspired electrolysis systems for producing specific C2+ products from CO2 or CO electroreduction. [ABSTRACT FROM AUTHOR]

A novel synthesis method has been developed for the construction of functionalized 2,4-diarylpyridines. The reaction involves several key processes, including a reduction reaction, Michael reaction, decarboxylation, intramolecular cyclization, oxidation, ring-opening and aromatization reaction. All of these processes are facilitated by heating a mixture of the starting materials in an environmentally benign solvent, propylene carbonate (PC), with the oxidant (air) and the catalyst Cu(OAc)2. This cascade reaction not only forms two new bonds but also cleaves three existing bonds in a single pot. The protocol presented in this study is a valuable tool for synthesizing functionalized unsymmetrical 2,4-diarylpyridines. [ABSTRACT FROM AUTHOR]

Treatment of the Schiff base ligands a–f with Li2[PdCl4]/NaAcO in methanol under reflux gave the single nuclear palladacycles 1a–1f, with the metal atom bonded to a terdentate monoanionic [C,N,S] iminic ligand and to a chloride ligand that completes the palladium coordination sphere. Reaction of 1a–1c with silver perchlorate/triphenylphosphine in acetone at room temperature yielded the single nuclear complexes 2a–2c as the perchlorate salts, after substitution of the chloride ligand by a triphenylphosphine. However, reaction of a–c with Na2[PdCl4]/NaAcO in methanol at room temperature also gave compounds 1a–1c albeit contaminated with small amounts of the corresponding free aldehyde (mixture A). Reaction of mixture A with silver perchlorate/triphenylphosphine in acetone at room temperature gave analogously 2a–2c with some of the corresponding free aldehyde (mixture B). Attempts to purify mixtures A and B via recrystallization produced single crystals of 5 and 6 respectively: two serendipitously formed complexes, bearing thiomethyl aniline and/or acetate ligands, and void of aldehyde or iminic residue; the structures contain eight- and six-membered rings of alternating palladium and nitrogen atoms, respectively. To clarify this situation the aniline itself was reacted with palladium(II) acetate or with Na2[PdCl4]; in the latter case after recrystallization a unique behavior is revealed, giving rise to a tetranuclear complex containing a Pd4N4 ring with three differing coordination environments on the palladium atoms. Treatment of 1d with Ph2PCH2PPh2 (dppm)/AgClO4 or with Ph2PCH2(PPh2)W(CO)5/AgClO4 gave 3d, with a mono-coordinated dppm ligand, and 4d, respectively; complex 3d could not be converted into 4d by reaction with W(CO)5(THF). Recrystallization of 4d gave a still further noticeable species, complex 8: a pentanuclear trans-configured heterometallic mixed valent Pd(II)/W(0) linear complex with the palladium atoms supported by two acetate and two thiomethyl aniline bridging ligands. The complexes were fully characterized by microanalysis, IR, 1H, and 31P NMR spectroscopies, as appropriate. The X-ray single-crystal analyses for compounds 1b, 5, 6, 7 and 8 are described. [ABSTRACT FROM AUTHOR]

To gain mechanistic insights into the acetate-assisted cyclometallations of arylimines promoted by [RuCl2(p-cymene)]2 in polar protic media, DFT geometry optimizations (with M06 and ωB97X-D3 functionals and the cc-pVDZ-PP[Ru] basis set) followed by DLPNO-CCSD(T)/CBS energy evaluations were performed using benzaldimine as a model substrate and methanol as the solvent (with CPCM or SMD models). The calculation results show that coordination of the imine to an acetate ruthenium precursor is followed by anion (chloride or acetate) dissociation as the rate-determining step of the process. H-Bonding of two explicit MeOH to the anion reduces the calculated activation energy to ca. 23 kcal mol−1, in good agreement with the experimental half-life at room temperature. Subsequent AMLA/CMD C–H activation of the intermediate cationic complexes is a faster, reversible process. Alternative reaction pathways involving neutral diacetate ruthenium complexes offer AMLA/CMD transition state structures of lower energy but are precluded due to higher energy barriers for the initial ligand exchange processes at ruthenium. Solvent assistance accelerates the final chloride/acetate exchange processes on the cycloruthenate intermediates, particularly when compression in the condensed phase is taken into consideration. The performance of six DFT functionals (with the aug-pVTZ-PP[Ru] basis set) was assessed using the DLPNO-CCSD(T)/CBS reference energies. Neutral diacetate ruthenium complexes were incorrectly predicted as being kinetically relevant when using hybrid DFT methods (PBE0-D3(BJ), M06-2X or ωB97M-V). Good agreement between the calculated barrier heights and our benchmark energy results was obtained by using double-hybrid DFT methods. PWPB95 with D3(BJ) or D4 dispersion energy corrections was found to be the most accurate (ΔG≠ MUE of ca. 1 kcal mol−1). This study may aid our understanding of and help with further experimental investigations of synthetically useful carboxylate-assisted C–H bond functionalizations involving (N,C)-cyclometallated (p-cymene)Ru(II) intermediate complexes in sustainable polar protic solvents. [ABSTRACT FROM AUTHOR]

The hydrogenation of acetic acid-derived cyclohexyl acetate (CHA) is becoming a safe, efficient and promising route for the production of cyclohexanol (CHOL), an important chemical to produce e-caprolactam. In this work, Cu-Zr catalysts were prepared via different methods for the hydrogenation of CHA. The results showed that a Cu3Zr7-SG catalyst prepared by the sol-gel (SG) method was superior to Cu3Zr7-CP and Cu3Zr7-IM catalysts prepared by the coprecipitation (CP) and impregnation (IM) method, respectively. The Cu3Zr7-SG catalyst showed 97.4% CHA conversion and 95.5% selectivity to CHOL along with 96.3% selectivity to ethanol at 250 1C under 3 MPa of H2. Moreover, the Cu3Zr7-SG catalyst showed a mass specific activity of up to 29.8 gCHA gCu-1 h-1, higher than other Cu-based catalysts under similar conditions. Based on detailed characterization studies, it was found that the larger weak acid sites, more weak and moderate basic sites, higher Cu+/(Cu0 + Cu+) and oxygen vacancies on the surface of the Cu3Zr7-SG catalyst were beneficial for the hydrogenation of CHA. [ABSTRACT FROM AUTHOR]

Puerarin 6′′-O-acetate (P6′′A), a puerarin derivative with a high stability and an improved permeability, exhibits a promising potential in drug development. The large-scale production of P6′′A through green synthesis procedures has never been achieved owing to the low availability of acetyl-CoA. Herein, the enzymatic synthesis of P6′′A in Escherichia coli cell factories overproducing acetyl-CoA has been achieved. Firstly, the effect of three acetyl-CoA-producing pathways on P6′′A conversion in E.coli was compared comprehensively. The pathways containing acetyl-CoA synthetase (ACS) or the pyruvate dehydrogenase (PDH) complex were thereby identified as favorable fluxes yielding more acetyl-CoA. Hence, cells co-expressing ACS and the PDH complex were selected as cell factories overproducing acetyl-CoA owing to the positive cooperativity of ACS and PDH. Subsequently, the maa gene encoding maltose acetyltransferase (MAT) was introduced into these acetyl-CoA-producing cell factories to form engineered strains Q1–Q14. After condition optimization, the engineered strain Q5 got a P6′′A yield of 0.98 g L−1 in M9P-Glc medium supplemented with 2.5 mM puerarin and 1.5% glucose. To further improve P6′′A production, the maa gene in Q5 was replaced by a mutant maaE125N gene to generate another engineered strain (Q15). Microbial production of P6′′A in Q15 was achieved through the centrifuge tube culture, the shake-flask culture and the 6-L reactor culture and the highest P6′′A yield of up to 2.02 g L−1 was obtained in the reactor fermentation. Enzymatically synthesized P6′′A displayed a high stability in human and mouse plasma, a dose-dependent cytotoxicity in HepG2 cells and an improved liposolubility. This research provides a feasible procedure for the green synthesis of puerarin monoesters and lays a foundation for druggability research on P6′′A. [ABSTRACT FROM AUTHOR]

In this work, low-crystalized and defective NiOx/graphene was synthesized by a facile electrolysis-solvothermal method. In the electrolytic process, Ni ions originate from the Ni anode, and graphene is produced from the graphite cathode. Then, Ni ions are reduced into oxides and deposited on graphene in the subsequent solvothermal process. The NiOx/graphene displays excellent electrocatalytic activity and selectivity for ethanol oxidation reaction to acetate. The peak current density was 296.5 mA cm−2 on a glassy carbon electrode. The FE of acetate was more than 93% at the potential range between 1.4 and 1.7 V. We propose that the mechanism is a cooperation between the chemical deprotonating process of ethanol by Ni3+ species and the electrochemical oxidation of the CH3CH2O* intermediate to acetate at the interface between NiOx and graphene. [ABSTRACT FROM AUTHOR]

A dinuclear nickel compound that features vanillin (van) and acetate (OAc) bridging ligands, [Ni2(μ-van)2(μ-OAc)(NCS)3(H2O)]·5H2O 1, was synthesized and characterized using various techniques. Crystal structure analysis revealed a pair of Ni(II) ions bridged by an acetate anion through a μ2-η1:η1 coordination mode. At the same time, vanillin bridges both nickel(II) centers through phenolic oxygen, separating the two Ni ions by a distance of 3.001(7) Å. The temperature-dependent magnetism indicates weak antiferromagnetic behaviour in compound 1, following the Curie–Weiss law with Curie constant C = 1.0145 cm3 K mol−1 and Weiss constant = −4.1 K. Compound 1 was evaluated for its ability to mimic the catechol oxidase enzyme using 3,5-di-tert-butylcatechol as a model substrate with a Kcat value of 157.1 × 102 h−1. Furthermore, compound 1 was tested for its cytotoxicity against HepG2 cancer cells and DNA cleavage properties. [ABSTRACT FROM AUTHOR]

A protocol for efficient N-alkylation of benzamides with alcohols in the presence of cobalt-nanocatalysts is described. Key to the success of this general methodology is the use of highly dispersed cobalt nanoparticles supported on carbon, which are obtained from the pyrolysis of cobalt(II) acetate and o-phenylenediamine as a ligand at suitable temperatures. The catalytic material shows a broad substrate scope and good tolerance to functional groups. Apart from the synthesis of a variety of secondary amides (>45 products), the catalyst allows for the conversion of more challenging aliphatic alcohols and amides, including biobased and macromolecular amides. The practical applicability of the catalyst is underlined by the successful recycling and reusability. [ABSTRACT FROM AUTHOR]

One mono-nuclear Ni(II) complex [NiL(CH3COO)] (1) and one di-nuclear Cu(II) complex, [Cu2L2(CH3-COO)2] (2), with pendant and bridging acetate moieties, respectively, have been synthesized using a novel N,N,O donor Schiff base ligand HL, 1-(((piperidine-2-ylmethyl)imino)methyl)naphthalene-2-al, prepared by the simple condensation of 2-hydroxy-1-naphthaldehyde and 2-amino methyl piperidine. With the aid of numerous spectroscopic studies, the three compounds described above have been properly characterized. The single crystal data analyses of both the complexes reveal that in complex 1, one deprotonated ligand, one pendant acetate ion, and one Ni(II) ion form a mononuclear distorted square planar geometry and in complex 2, each Cu(II) center connects with one deprotonated ligand and a double m1.1-acetato-bridge forming a distorted trigonal bipyramidal geometry, while two acetate bridges connect two Cu(II) centers forming a dinuclear complex. After rigorous characterization, both the complexes are investigated to check their binding efficacy with biomacromolecules like DNA and HSA, and the results, obtained from a variety of biophysical studies like absorption, fluorescence, and circular dichroism-based titrations, clearly disclose that both the complexes have an affinity for binding with DNA and HSA. Fluorescence displacement analysis and a DNA melting study demonstrate different modes of binding for the two complexes with the DNA host, namely intercalative mode associated with groove binding for complex 1 and only groove binding for complex 2. Circular dichroism spectral analysis of HSA during interaction with the complexes confirms some structural changes in HSA upon binding. Determination of the thermodynamic parameters implies the binding interactions of HSA with the two complexes to be spontaneous. After a convincing study of the complex--biomacromolecule binding interactions, an MTT assay study on both cancer and normal cells reveals that of the two complexes, complex 2 is the better one, showing superior anticancer properties together with low toxicity to a normal cell. Finally, an apoptotic cell-killing pathway of the studied complexes has been confirmed by a nuclear staining study. [ABSTRACT FROM AUTHOR]

Emulsion gels synergistically stabilized by different polysaccharides and modified shea butter were reported in this work. The effects of different oil phase contents and polysaccharide types on particle size and rheological properties of emulsion gels were investigated. Micromorphology of emulsion droplets was analyzed using cryo-SEM and the stabilization mechanism for the possible formation of emulsion gels was also elucidated. Polysaccharide particles have two main roles in the process of forming emulsion gels: one is with modified shea butter as the stabilizer; the other is as the suspending matrix suspending, supporting and immobilizing droplets. The emulsifying property of the complex was determined by the wettability and size of the polysaccharide particles and the level of intermolecular interactions. Emulsion gels exhibited good environmental stability against prolonged storage, heating and freezing. These emulsion gels were used to encapsulate and deliver α-tocopherol acetate. The encapsulation efficiency was higher over 30 days compared with the unencapsulated olive oil control group. This research would be of importance not only for extending the knowledge about emulsion gels by modified natural vegetable oil and polysaccharides but also for the development of novel, eco-friendly and sustainable emulsion gels for food, cosmetic and medicine formulations. [ABSTRACT FROM AUTHOR]

Three new nickel Schiff base complexes were prepared using a two-step procedure that involves initial selective dialkylation of 2,4,6-trihydroxybenzaldehyde, followed by reaction with 1,2-phenylenediamine and nickel(II) acetate. Each of the complexes possessed the same Schiff base core but differed in the identity of the four pendant groups. All complexes were characterised by microanalysis, NMR spectroscopy and ESI mass spectrometry. In addition, two of the complexes were also characterised in the solid state using X-ray crystallography, which confirmed the presence of a square planar geometry around the metal ion. The DNA binding properties of the three nickel complexes with double stranded DNA and a range of G-quadruplex DNA structures were explored using ESI mass spectrometry, CD spectroscopy, UV melting curves, Fluorescence Resonance Energy Transfer (FRET) assays, Fluorescent Indicator Displacement (FID) assays and molecular docking studies. These techniques confirmed the ability of the three nickel complexes to bind to most of the DNA molecules examined, as well as stabilise the latter in several instances. In addition, the results of these investigations provided evidence that pendant groups with morpholine rings generally reduced DNA binding behaviour, whilst pendants featuring piperidine ring systems attached to the Schiff base core by three and not two methylene linkers often showed the greatest extent of binding or DNA stabilisation. [ABSTRACT FROM AUTHOR]

The solution behavior of complex [Rh(COD)(μ-OAc)]2 in the absence and presence of PPN+OAc− in dichloromethane has been investigated in detail by multinuclear NMR spectroscopy. Without additional acetate ions, the compound shows dynamic behavior at room temperature, consistent with an inversion of its C2v structure. Addition of PPN+OAc− reveals an equilibrated generation of [Rh(COD)(OAc)2]−. Rapid exchange is observed at room temperature between the neutral dimer and the anionic mononuclear complex, as well as between the anionic complex and free acetate. Lowering the temperature to 213 K freezes the exchange between the two Rh complexes, but fast exchange between the anionic Rh complex and free acetate maintains coalesced Me (1H and 13C) and COO (13C) NMR resonances. DFT calculations support the experimental data and lean in favour of a dissociative mechanism for the acetate exchange in [Rh(COD)(OAc)2]−. The acetate ligands in complex [Rh(COD)(μ-OAc)]2 are also exchanged in a biphasic (water/organic) system with the methacrylic acid (MAA) functions of hydrosoluble [MMA0.5-co-PEOMA0.5]30 copolymer chains (PEOMA = poly(ethylene oxide) methyl ether methacrylate), resulting in transfer of the Rh complex to the aqueous phase. Exchange with the MAA functions in the same polymer equally takes place for the chloride ligands of [Rh(COD)(μ-Cl)]2. The latter phenomenon rationalizes the coagulation of a core-crosslinked micelle (CCM) latex, where MMA functions are present on the hydrophilic CCM shell, when a dichloromethane solution of [Rh(COD)(μ-Cl)]2 is added. [ABSTRACT FROM AUTHOR]

Heterometallic oxo clusters have been attracting intensive interest due to their unique properties originating from the synergistic interactions between different components. Herein, we report the construction and catalytic applications of a family of copper-doped polyoxo-titanium clusters (Cu-PTCs) coordinated with different acetate derivative ligands. The solvothermal reactions of metal salts and trimethylacetic acid or 1,2-phenylenediacetic acid in ethanol produced Ti6Cu3(μ3-O)4(μ2-O)(OEt)16(L1)4 (L1 = trimethyl acetate, PTC-367) and H2Ti8Cu2Br2(μ4-O)2(μ2-O)4(OEt)20(L2)2 (L2 = 1,2-phenylenediacetate, PTC-368), respectively. When smaller acetic acid was introduced as a stabilizing ligand, higher nuclei H2Ti16Cu3(μ4-O)5(μ3-O)15(μ2-O)3(OiPr)18(Ac)8 (Ac = acetate, PTC-369) and H3Ti29Cu3(μ4-O)6(μ3-O)30(μ2-O)8(OiPr)17(Ac)20 (PTC-370) were prepared. The number of metal ions exposed on the surface of the four clusters changes due to variations in the steric hindrance of functionalizing ligands, and theoretically, so does their catalytic activity as Lewis acids. In light of this, we conducted a carbon dioxide cycloaddition reaction in an atmospheric environment and the four obtained compounds displayed increasing catalytic activities from PTC-367 to PTC-370. These results provide a feasible synthetic method for modulating the structures of Cu-doped titanium oxide materials and improving their catalytic activities. [ABSTRACT FROM AUTHOR]

A new 15-membered pyridine-based macrocyclic ligand containing one acetate pendant arm (N-carboxymethyl-3,12,18-triaza-6,9-dioxabicyclo[12.3.1]octadeca-1(18),14,16-triene, L1) was synthesized and its Mn(II) complex MnL1 was investigated in the context of MRI contrast agent development. The X-ray molecular structure of MnL1 confirmed a coordination number of seven with an axially compressed pentagonal bipyramidal geometry and one coordination site available for an inner-sphere water molecule. The protonation constants of L1 and the stability constants of Mn(II), Zn(II), Cu(II) and Ca(II) complexes were determined by potentiometry, and revealed higher thermodynamic stabilities in comparison with complexes of 15-pyN3O2, the parent macrocycle without an acetate pendant arm. The MnL1 complex is fully formed at physiological pH 7.4, but it shows fast dissociation kinetics, as followed by relaxometry in the presence of an excess of Zn(II). The short dissociation half-life estimated for physiological pH (ca. 3 minutes) is related to fast spontaneous dissociation of the non-protonated complex. At lower pH values, the proton-assisted dissociation pathway becomes important, while the Zn(II) concentration has no effect on the dissociation rate. 17O NMR and 1H NMRD data indicated the presence of one inner-sphere water molecule with a rather slow exchange (k 298ex = 4.5 × 106 s−1) and provided information about other microscopic parameters governing relaxation. The relaxivity (r1 = 2.45 mM−1 s−1 at 20 MHz, 25 °C) corresponds to typical values for monohydrated Mn(II) chelates. Overall, the acetate pendant arm in L1 has a beneficial effect with respect to 15-pyN3O2 in increasing the thermodynamic stability and kinetic inertness of its Mn(II) complex, but leads to a reduced number of inner-sphere water molecules and thus lower relaxivity. [ABSTRACT FROM AUTHOR]

The reaction of 2-(2-(dicyanomethylene)hydrazineyl)benzoic acid (H2L1) with copper(II) acetate in the absence or presence of imidazole (im), 4,4′-bipyridine (4,4′-bipy) or pyridine (py) leads to the new complexes [Cu2(CH3OH)2(μ-L1a)2] (1), [Cu(L1a)(im)] (2), [Cu(L1a)(H2O)(4,4′-bipy)]·H2O (3) or [Cu(L1a)(py)]n (4), respectively, where (L1a)2− = (Z)-1-(2-carboxylatophenyl)-2-(1-cyano-2-imino-2-methoxyethylidene)hydrazin-1-ide. A one-pot activation of nitrile groups in the reaction of copper(II) acetate monohydrate with 2-(2-(dicyanomethylene)hydrazineyl)terephthalic acid (H3L2) in the presence of pyridine in methanol affords the trinuclear Cu(II) complex [Cu(py)2{Cu(py)(μ-L2a)}2] (5), where (L2a)3− = (Z)-2-((1-cyano-2-imino-2-methoxyethylidene)-1-(2,5-dicarboxylatophenyl)hydrazin-1-ide). Both arylhydrazone ligands and the auxiliary ligands were used to modulate the nuclearity and design of the supramolecular arrangements of the obtained Cu(II) complexes. The complexes were characterized by elemental analyses, electrospray ionization mass spectrometry (ESI-MS), and FT-IR spectroscopy. Their molecular structures were established using single crystal X-ray diffraction (SCXRD) analysis. The catalytic activity of the complexes was investigated for the microwave assisted 1,3-dipolar azide–alkyne cycloaddition reaction using a mixture of water and glycerol as reaction medium. Pre-catalyst 1 was found to be the most efficient one by affording a quantitative conversion to 1,4-disubstituted-1,2,3-triazoles after 30 minutes at 125 °C. The catalytic system proceeds with a broad scope of substrates according to "Click" rules. [ABSTRACT FROM AUTHOR]

A concise and practical approach for expedient synthesis of substituted benzoxazolpyrroles, benzothiazolpyrroles and indolizines by three-component cascade annulative coupling of an aldehyde, 2-heteroaryl acetonitrile and an isocyanide in the presence of 10 mol% 2-(hydroxymethyl)pyrrolidinium acetate has been devised in high yields for the first time. The compatibility with a wide range of functional groups makes this domino formation of one C-C and two C-N bonds interesting. In particular, the heterocycles derived from 2-bromobenzaldehydes are further converted into indole-fused novel pentacyclic (6-5-5-5-6) heteroaromatic compounds by Pd(II)-catalyzed intramolecular N-arylation via a cross-dehydrobromination reaction. This annulative protocol not only provides an efficient method to access tricyclic heteroaromatics, but also enriches the research domain of pentacyclic scaffolds. [ABSTRACT FROM AUTHOR]

The reaction of (NMe4)2[NiII(LPh)(OAc)] (1[OAc], LPh = 2,2′,2′′-nitrilo-tris-(N-phenylacetamide); OAc = acetate) with 3-chloroperoxybenzoic acid (m-CPBA) resulted in the formation of a self-hydroxylated NiIII-phenolate complex, 2, where one of the phenyl groups of LPh underwent hydroxylation. 2 was characterised by UV-Vis, EPR, and XAS spectroscopies and ESI-MS. 2 decayed to yield a previously characterised NiII-phenolate complex, 3. We postulate that self-hydroxylation was mediated by a formally NiIV＝O oxidant, formed from the reaction of 1[OAc] with m-CPBA, which undergoes electrophilic aromatic substitution to yield 2. This is supported by an analysis of the kinetic and thermodynamic properties of the reaction of 1[OAc] with m-CPBA. Addition of exogenous hydrocarbon substrates intercepted the self-hydroxylation process, producing hydroxylated products, providing further support for the formally NiIV＝O entity. This study demonstrates that the reaction between NiII salts and m-CPBA can lead to potent metal-based oxidants, in contrast to recent studies demonstrating carboxyl radical is a radical free-chain reaction initiator in NiII/m-CPBA hydrocarbon oxidation catalysis. [ABSTRACT FROM AUTHOR]

The structure of CsPbI3 nanocrystals (NCs) with excellent photoelectric properties easily collapses, which hinders their application in light-emitting diodes (LEDs). Herein, we accomplished the synthesis of efficient and stable CsPbI3 NCs by regulating structural rigidity under the synergistic effect of Mg2+ and AcO− ions. The introduced AcO− and Mg2+ ions increase surface steric hindrance and defect formation energy, which enhances the structural rigidity of the perovskite. As a result, the CsPbI3 NCs display an outstanding photoluminescence quantum yield of 95.7%, in conjunction with reduced defect state density, balanced carrier injection, and distinguished conductivity. Remarkably, the modified CsPbI3 NCs exhibit excellent stability under ambient conditions for 180 days and can even survive when the temperature reaches 150 °C. Given their enhanced structural rigidity, LEDs made from these modified CsPbI3 NCs exhibit a maximum luminance and an EQE of 3281 cd m−2 and 13.2%, respectively, which are significantly improved compared with those of unmodified CsPbI3 NC LEDs. [ABSTRACT FROM AUTHOR]

Adjusting the internal porous environment of MOFs to enhance their adsorption properties is considered an effective strategy to improve their gas separation performance. Herein, 1-ethyl-3-methyl-imidazolium acetate ([Emim][Ac]) was encapsulated in UiO-66 by an impregnation method for the improvement of carbon dioxide (CO2) capture performance. The synthesis and detailed characterizations of the developed [Emim][Ac]@UiO-66 are reported, and the effect of the loading amount of [Emim][Ac] on the CO2 separation performance was also studied. The obtained [Emim][Ac]@UiO-66 could efficiently show the synergistic effect of the adsorption of CO2 between [Emim][Ac] and UiO-66. The optimized [Emim][Ac]@UiO-66 exhibited a much higher CO2 adsorption capacity at 298 K and 1.0 bar, affording 2 times the CO2 uptake than its original UiO-66. In addition, the CO2/N2 selectivity and CO2/CH4 selectivity of [Emim][Ac]@UiO-66-3.5% are significantly higher than those of UiO-66. This study for designing various MOF-encapsulated ionic liquids potentially paves the way for the development of highly efficient absorbents for gas separations. [ABSTRACT FROM AUTHOR]

An efficient visible light-promoted C(sp3)–H functionalization of alkyl arylacetates has been developed using CS2 and amines by eosin Y/I2 dual catalysis to achieve the formation of S-benzyl dithiocarbamate acetates. [ABSTRACT FROM AUTHOR]

In this work, fibrous ZnO microrods were synthesized through a macroemulsion-mediated solvothermal method using two different precursors: zinc nitrate and zinc acetate. Initially, we optimized urea concentration using the zinc acetate precursor, producing homogeneous ZnO microrods. We then applied this optimum condition to synthesize ZnO using zinc nitrate. XRD and Raman spectroscopy analyses confirmed that both precursors resulted in ZnO with a wurtzite crystal structure. Raman spectroscopy also reveals the presence of the B1L silent mode in both samples, which is caused by crystal defects. Morphological observation using FESEM shows that both samples have rod shapes with different diameters and lengths but similar aspect ratios. Moreover, the detailed morphology indicates that the ZnO synthesized using zinc acetate has a more uniform fibrous morphology than the ZnO synthesized using zinc nitrate. The uniform fibrous morphology might be induced by the organic counterions, the acetate ion (CH3COO−), in the mixture during the synthesis process. The uniform fibrous ZnO microrod provides excellent properties, including a higher surface area, smaller bandgap energy, and higher total density of defects. The photocatalytic activity of the synthesized ZnO was determined through in situ observation using time-dependent photoluminescence spectroscopy measurements. The photocatalytic test shows that the uniform fibrous ZnO microrods have higher photocatalytic efficiency (73.82%) within 60 minutes of irradiation and a higher photodegradation rate (k = 0.1745 min−1). The recovery test confirmed that the ZnO_Ac_U2 photocatalyst also has higher stability. The higher photocatalytic activity might be due to the synergistic effect among the higher surface area, smaller bandgap energy, higher total density of defects, and uniform fibrous morphology. Moreover, the in situ measurement using time-dependent photoluminescence spectroscopy can collect data at decent intervals, resulting in a more reliable value of the rate constant. [ABSTRACT FROM AUTHOR]

Guanidinium–naphthalenedisulfonic acid (GNPS) was used as a molecular catcher because (i) it contains a cavity and channel in the network; (ii) NH2+ can be used as a hydrogen bond donor, and SO3− can be used as a hydrogen bond acceptor; (iii) the co-planar naphthalene rings can form aromatic interactions with guest molecules. The liquid guests 1–8 [(−)-isopulegol (1), (−)-menthyl acetate (2), isoeugenol (3), 2,6-dimethylaniline (4), methyleugenol (5), 2,6-diisopropylaniline (6), methyl salicylate (7) and L (−)-carvone (8)] are successfully encapsulated in the cavity of GNPS and eight new crystals were obtained. Both aromatic and non-aromatic molecules form hydrogen bonds and C–H⋯π interactions with GNPS. Co-crystallization of 1–4 with GNPS led to stronger C–H⋯π interactions as compared to the previously reported GBPS. Furthermore, compounds 5–8 which were not co-crystallized with GBPS were found to be encapsulated in the cavity of GNPS. We found that the aromatic cavity of GNPS with hydrogen bonding and enhanced C–H⋯π interactions can be regarded as a useful tool for the structural determination of liquid molecules. Furthermore, the correct absolute configurations of 1, 2 and 8 can be assigned based on the small Flack parameters because of the presence of sulfur atoms in the host molecule GNPS. [ABSTRACT FROM AUTHOR]

Using two different metalloligands [NiLA] and [NiLB], developed using two different N2O2 donor Schiff bases, H2LA 6,6′-((1E,1′E)-((2,2-dimethylpropane-1,3-diyl)bis(azaneylylidene))bis(2-methoxyphenol) and H2LB 6,6′-((1E,1′E)-((2,2 (2-ethoxyphenol), two new tetra- and trinuclear heterometallic complexes, [(NiLA)2(CH3COO)2(SCN)2(Co)2] (complex 1) and [(NiLB)2(SCN)2Mn] (complex 2), have been synthesized. The two newly formed complexes have primarily been characterized using several spectroscopic techniques. According to the single-crystal structural study, the metalloligand portion is shared by both crystals. Complex 1 is a tetranuclear complex where Ni(II) is connected to Co(II) via acetate and phenoxide bridging, whereas complex 2 is a trinuclear complex where each Ni(II) center is coordinated to Mn(II) via phenoxide bridging only. It is interesting to note that the thiocyanate moiety in complex 1 is linked to Co(II), whereas in complex 2, it is linked to Ni(II) as a secondary anionic residue. Following structural analysis, both complexes were exposed to catecholase-like activity to test their ability to aerially oxidize 3,5-di-tert-butylcatechol. The calculated turnover numbers (Kcat) 355 h−1 and 286 h−1 for complexes 1 and 2, respectively, unveiled that complex 1 is more susceptible to this catalytic process. The generation of Ni(I) in complex 1 is more favorable than the formation of Mn(I) in complex 2 during catalysis and this is the factor responsible for the higher susceptibility of complex 1 towards the catalytic process. To determine whether both the studied complexes can function as effective Schottky devices, the band gap values for complexes 1 and 2 were used to calculate the diode parameters. The results show that complex 1 will function as a better Schottky device than the complex 2. [ABSTRACT FROM AUTHOR]

Two palladium complexes, [Pd(L1)(OAc))] (1) and [Pd(L2)(OAc))] (2), have been synthesized by reacting Pd(OAc)2 and new thioetherazo (HL) ligands (HL = 2(RS)C6H4NH–N＝C(COCH3)–SC6H5, R = C6H5 (HL1), CH3 (HL2)). The ligands and their complexes have been characterized by IR, NMR and UV-Vis spectroscopic techniques and their geometries have been confirmed by X-ray crystal structure analysis for complexes 1 and 2, and HL1 as well. The acetate group is coplanar with the coordination plane in both complexes, which is due to the S⋯O chalcogen bonding interactions. This conclusion is supported by the Quantum Theory of Atoms in Molecules (QTAIM) analysis of the electron density. The isomerism in the two complexes was investigated theoretically, and the calculations proved that the reported molecular structures in the crystals are the most stable isomers. The antitumor potential of the ligands and complexes was investigated preliminarily by applying an MTT assay on cancer and normal cell lines along with cisplatin as a standard anticancer drug. It was found that the two palladium(II) complexes are more cytotoxic toward cancer cells than their analogous ligands. Complexes 1 and 2 showed high activity toward human breast cancer cells (T47D) with IC50 values of 61.6 ± 12 and 72.3 ± 8.4 μM ml−1, respectively. However, complex 1 revealed some toxicity in a normal cell line (VERO). On the other hand, both complexes exhibited less potency in human colon cancer cells (HCT 116 cell line). These findings indicated that the antiproliferative activity is improved when the ligands (HL1–HL2) are integrated into the metal center. [ABSTRACT FROM AUTHOR]

The improvement of solubility and dissolution properties are the focus of research on poorly water-soluble APIs. Cocrystallization, which offers a different approach to modify properties of APIs, has gained considerable interest recently. Herein, we designed and synthesized two novel nomegestrol acetate (NA) cocrystals using 2,5-dihydroxybenzoic acid (DA) and 4-hydroxybenzoic acid (PA). Both cocrystals were characterized by single-crystal X-ray diffractometry (SCXRD), powder X-ray diffractometry (PXRD), Fourier transform infrared spectroscopy (FT-IR), and differential scanning calorimetry (DSC). Powder dissolution studies indicated that the concentrations of NA–DA and NA–PA at 3 h are approximately 5 and 4 times that of NA in deionized water, respectively. These successful results imply that the cocrystallization strategy is an effective means to improve the solubility of NA. [ABSTRACT FROM AUTHOR]

Metal carboxylates are an extensive family of coordination compounds of growing importance in materials science; hence, there is a need for improving the characterization methods for these complexes, especially at the surface level. So far, the use of the XPS technique in this field has been scarce. This work is intended to explore the capabilities of XPS as a reliable probe for the nature of the carboxyl–metal bond. For this, a series of metal acetates was selected as model compounds, covering a wide range of metal cations and coordination geometries. The high-resolution spectra of the C 1s, O 1s, and Auger O KVV lines were recorded and analyzed using curve-fitting procedures. The results indicate that the chemical-state plot for the oxygen atom provides a suitable means for distinguishing metal acetates as a function of the metal cation, whereas the positions of the compounds are not sensitive to the coordination mode. The detected variations in the core-hole extra-atomic relaxation energy can be correlated with the polarizability of the M–O bond due to an admixture of metal states, while the derived variations in the ground-state core eigenvalue depend on the interplay between the electrostatic potential generated by the cation and the degree of ligand-to-metal charge transfer. [ABSTRACT FROM AUTHOR]

Addition of 2-aminobenzothiazole (abt) and substituted derivatives to Hg(OAc)2 leads to the high yield formation of ortho-cyano-aminothiophenolate (ocap) complexes [Hg{SC6H3XN(C≡N)}]n (X = H, Me, Cl, Br, NO2) resulting from dehydrogenation and C–S bond cleavage. The reaction appears to be unique to Hg(OAc)2 and with HgCl2 the product [HgCl2(abt)]n contains an intact abt ligand, but reacts with acetate to afford the ocap complex [Hg{SC6H4N(C≡N)}]n. Binding of abt to Hg(II) has previously been probed in molecular structures of [Hg(sac)2(abt)L] (L = MeOH, DMSO) and these have been reexamined to understand the perturbation of abt upon coordination. When the reaction of abt and Hg(OAc)2 was carried out at low temperatures the intermediate [Hg(κ2-OAc)(EtOH)(μ-HNCNSC6H4)]2 was isolated resulting from a single ligand deprotonation thus allowing a mechanism for ring-opening to be proposed. Reactions of [Hg{SC6H3XN(C≡N)}]n with mono- and bidentate phosphines have been studied, affording a series of complexes in which the ocap ligands adopt four different binding modes in the solid state, as shown by a number of crystallographic studies. In all, the ligand chelates to a single mercury centre but spans to the second via either: (i) a simple S,N-chelate, (ii) coordination through nitrogen of the C≡N group, (iii) the sulfur acting as a thiolate-bridge, (iv) both thiolate bridging and cyanide coordination. With PPh3 two different binding modes are seen in complexes [Hg{SC6H3XN(C≡N)}(PPh3)]2 being dependant upon the nature of the arene-substituent, while addition of excess PPh3 affords mononuclear [Hg{SC6H3XN(C≡N)}(PPh3)2]. With dppm, binuclear [Hg{SC6H3XN(C≡N)}(κ1-dppm)]2 result in which the diphosphine binds in a monodentate fashion. With the more flexible diphosphines, dppe and dppb, coordination polymers [Hg{SC6H3XN(C≡N)}(κ1,κ1-diphosphine)]n result in which ocap binds in a simple chelate fashion. Somewhat unexpectedly, with dppp, binuclear complexes [Hg2{SC6H3XN(C≡N)}2(μ,κ1,κ1-dppp)] result in which two diphosphines bridge the Hg2 centre, while with dppf mononuclear chelates are proposed to result. Thus, the simple and high-yielding ring-opening of 2-aminobenzothiazole and substituted derivatives by mercuric acetate provides ready access to a range of novel ortho-cyano-aminothiophenolate complexes, being shown to be a highly versatile ligand that can adopt a number of different coordination modes. [ABSTRACT FROM AUTHOR]

A unique π-conjugated benzothiadiazole-ortho-vanillin ligand (HL), characterized by single crystal X-ray diffraction and DFT calculations, has been prepared by condensation between 4-amino-benzothiadiazole (BTD) and ortho-vanillin. Its reaction with cobalt(II) acetate afforded the complex of formula [CoL2]·CH2Cl2 (1), for which the coordination environment of the cobalt centre is a distorted octahedron and the ligand acts as a monoanionic tridentate NNO chelate in its phenolate form. Intermolecular π–π stacking interactions between the π-conjugated BTD units provide an antiferromagnetic coupling pathway, as indicated by the analysis of the dc magnetic measurements of a crystalline sample of the complex and supported by DFT type calculations. The static magnetic behaviour of 1 is analysed according to spin–orbit coupling and zero-field splitting models. Remarkably, the complex exhibits slow relaxation of the magnetization under dc applied magnetic fields being thus a new example of field-induced mononuclear single-molecule magnet (SMM). [ABSTRACT FROM AUTHOR]

Four copper(II)-flavonolate compounds of type [Cu(LR)(fla)] {where LR = 2-(p-R-benzyl(dipyridin-2-ylmethyl)amino)acetate; R = –OMe (1), –H (2), –Cl (3) and –NO2 (4)} have been developed as a structural and functional enzyme–substrate (ES) model of the Cu2+-containing quercetin 2,4-dioxygenase enzyme. The ES model complexes 1–4 are synthesized by reacting 3-hydroxyflavone in the presence of a base with the respective acetate-bound copper(II) complexes, [Cu(LR)(OAc)]. In the presence of dioxygen the ES model complexes undergo enzyme-type oxygenolysis of flavonolate (dioxygenase type bond cleavage reaction) at 80 °C in DMF. The reactivity shows a substituent group dependent order as –OMe (1) > –H (2) > –Cl (3) > −NO2 (4). Experimental and theoretical studies suggest a single-electron transfer (SET) from flavonolate to dioxygen, rather than valence tautomerism {[CuII(fla−)] ↔ [CuI(fla˙)]}, to generate the reactive flavonoxy radical (fla˙) that reacts further with the superoxide radical to bring about the oxygenative ring opening reaction. The SET pathway has been further verified by studying the dioxygenation reaction with a redox-inactive Zn2+ complex, [Zn(LOMe)(fla)] (5). [ABSTRACT FROM AUTHOR]

A nanostructured molybdenum disulfide loaded on reduced graphene oxide (MoS2-rGO) nanocomposite is prepared using a simple and facile one-pot method. Raman spectra, XRD, TGA, SEM and electrochemical experiments are applied for the characterization of the nanocomposite. Furthermore, the MoS2-rGO nanocomposite is used as an electrochemical sensing platform for detecting cyproterone acetate (CPA). The rGO acts as an electron transfer layer that can improve the electronic transmission rate, and the introduction of MoS2 can prevent the aggregation of rGO and increase significantly the effective surface area. Owing to the synergistic effect of MoS2 and rGO, the MoS2-rGO nanocomposite film shows a wider linear range and higher sensitivity towards CPA, superior to that of the pristine MoS2 and rGO film. A linear range from 4.0 × 10−8 to 1.0 × 10−5 mol L−1 and detection limit of 1.12 × 10−8 mol L−1 for CPA are achieved. In addition, the presented method is used for detecting CPA in pharmaceutical samples with satisfactory results. This study provides a promising electrochemical sensing platform for rapid and sensitive analysis of CPA. [ABSTRACT FROM AUTHOR]

In this contribution, we describe the synthesis, spectroscopic and structural characterization, as well as the electrochemical behavior of a series of four chiral ferrocene-functionalized Schiff base compounds derived from enantiomerically pure (1R,2R)-(−)-1,2-diaminocyclohexane. The ferrocene enaminones 3 and 4 were obtained upon monocondensation of ferrocenoylacetone Fc–C(＝O)CH2C(＝O)R (R = CH3, 1; 4-C6H4OH, 2; Fc = (η5-C5H5)Fe(η5-C5H4)) with one amino group of the primary diamine. The two bimetallic complexes 5 and 6 were prepared via a one-pot three-components template procedure involving half-unit 3, 4-methoxysalicylaldehyde and tetrahydrated zinc(II) nitrate for 5, and half-unit 4, 4-formyl-3-hydroxybenzoic acid and palladium(II) acetate for 6. All the syntheses were carried out in refluxing ethanol and compounds 3–6 were isolated as thermally stable, air and moisture compatible colored solids in 71–83% yields. They were characterized by several analytical (EA, ESI-MS) and spectroscopic methods (1H/13C NMR, FT-IR, UV-vis), including the molecular structures of 3 and 4 that were unequivocally established by single crystal X-ray diffraction analyses. Both crystallize in the orthorhombic non-centrosymmetric space group P212121 with two (R,R)-(−)-chiral carbon atoms in the structures. Cyclic voltammetry showed that the greatest anodic shifts (270 mV) of the ferrocenyl Fe(II)/Fe(III) redox potentials are observed for the D-π-A push–pull derivative 6. Beyond experimental characterization, DFT- and TDDFT-based theoretical analyses of the new chiral ferrocene-containing Schiff base complexes allow interpretation of their observed spectroscopic, structural and electronic features. [ABSTRACT FROM AUTHOR]

In order to investigate the electronic states of emissive tautomers (T*) of aromatic-urea compounds formed via excited-state intermolecular proton transfer (ESPT) with acetate anion (Ac), a new aromatic-urea compound (3FU) bearing fluoranthene, which has electron-accepting ability, was prepared. The absorption and fluorescence properties of 3FU were investigated using tetrabutylammonium acetate (TBAAc) and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as proton acceptors. In the presence of DBU, an N–H proton of 3FU is abstracted in the ground state to form an anionic structure, which is not given in the presence of TBAAc. The fluorescence spectrum of the proton-abstracted anionic structure was found to be almost identical to that of T* generated by ESPT with Ac, indicating that the electronic state of T* has an anionic structure. Furthermore, using the fluorescence quantum yield of the anionic structure, the deactivation rate constant of the normal form (N*) was estimated for the first time. Kinetic analysis using the obtained rate constant for N* allowed us to calculate the radiative and nonradiative rate constants of N* and T* and revealed that proton acceptors affect the nonradiative deactivation rate constant of N* rather than that of T*. [ABSTRACT FROM AUTHOR]

Constructing microbial factories offers a sustainable strategy for terpenoid synthesis; however, the accumulation of terpenoid products is often toxic to cells and hampers production yields. Here, we developed a bioderivatization strategy that successfully alleviates the toxicity of the end-product and maximizes the biochemical production of geraniol in Escherichia coli. We observed that the conversion of geraniol to less toxic geranyl acetate, which is an esterified derivative of geraniol, had a significant positive effect on productivity. Subsequently, the high concentration and purity of geraniol was recovered by the combined hydrolysis of geranyl acetate and solid phase adsorption. These findings demonstrate that a combination of bioderivatization and engineering approaches for the biosynthesis of a relatively toxic chemical (geraniol) can mitigate cytotoxicity while further promoting production efficiency. Finally, the maximal titer of these engineering strategies accumulated 13.19 g L−1 of geraniol by fed-batch fermentation in a 10-L fermentor. This study highlights the ability of this system to address the challenges associated with toxic geraniol accumulation. More broadly, the developed approach could also be considered for metabolic engineering of other similar chemicals. [ABSTRACT FROM AUTHOR]

Agave bagasse (AG) is a potential bioenergy feedstock due to its high biomass productivity, even in semiarid lands. In particular, ionic liquid (IL) pretreatment using aprotic ILs (AILs) has greatly reduced AG recalcitrance towards downstream processing by lowering lignin content and achieving high sugar yields. However, AIL's low biocompatibility towards enzymes and bacteria combined with the high initial cost has limited further development of this technology. In a wash-free one-pot (OP) ethanol conversion process, the evaluation of AG pretreatment with a biocompatible low-cost protic IL (PIL), 2-hydroxyethylammonium acetate ([2-HEA][OAc]) was achieved, where PIL pretreatment was followed by enzymatic saccharification, then ethanol fermentation in a single vessel. The pretreatment conditions were optimized using a central composite design to enable high sugar conversion at low PIL content. Under optimized pretreatment conditions (160 °C, 60% IL loading and 1.5 h), a yield of 132 kg of ethanol per Ton of untreated biomass was estimated using high solids loading (30% solids loading) under a PIL-OP scheme. High lignin removal (>50%), a decreased cellulose crystallinity, and high glucan conversion (>85%) were achieved with PIL-pretreated AG comparable to yields obtained in an AIL-AG pretreated sample using 1-ethyl-3-methyl-imidazolium acetate ([C2C1Im][OAc]). These results using [2-HEA][OAc] demonstrate the potential of AG in an OP scheme with improved total ethanol yields paving the way towards a more feasible IL-based biorefinery. [ABSTRACT FROM AUTHOR]

Hybrid phosphines usually combine a phosphine moiety with another heteroatom secondary donor group in their structures while compounds equipped with hydrocarbyl π–donor moieties remain uncommon. This contribution reports the synthesis and structural characterization of the first P/π-allyl-chelating complexes that were obtained using the structurally flexible and redox-active ferrocene unit as the scaffold, viz. [PdCl(R2PfcCHCHCH2-η3:κP)] (1R; R = Ph and cyclohexyl (Cy); fc = ferrocene-1,1′-diyl). These compounds were synthesized from the respective phosphinoferrocene carboxaldehydes R2PfcCHO via reaction with vinylmagnesium bromide to generate 1-(phosphinoferrocenyl)allyl alcohols, which were subsequently acetylated. The resulting allyl acetates reacted smoothly with [Pd2(dba)3]/[Et3NH]Cl (dba = dibenzylideneacetone) to produce the target compounds. Complexes 1R and their nontethered analogues [PdCl(η3-C3H5)(FcPR2-κP)] (5R; Fc = ferrocenyl) were evaluated as pre-catalysts for the Pd-catalysed allylic amination of cinnamyl acetate with aliphatic amines and Suzuki–Miyaura-type cross-coupling of 4-tolylboronic acid with benzoyl chloride. In these reactions, better results were achieved with compounds 5R (particularly with 5Ph), presumably because they form more stable LPd(0)-type catalysts. [ABSTRACT FROM AUTHOR]

A metal-free and oxidant-free procedure for the sulfonylation of Baylis–Hillman acetates with sulfonyl hydrazides under the irradiation of visible light and open-air conditions at room temperature is described. This transformation has high yields (up to 92%), excellent stereoselectivity, broad substrate scope, good functional group tolerance, and mild reaction conditions. Moreover, mechanistic studies indicate that a sulfonyl radical pathway is involved in this reaction. [ABSTRACT FROM AUTHOR]

Transition metal oxides (TMOs) are prospective anode materials for lithium-ion batteries (LIBs), owing to their high theoretical specific capacity. However, the inherently low conductivity of TMOs restricts their application. The coupling of lithium-ion conducting polymer ligands with TMO structures is favorable for the dynamics of electrochemical processes. Herein, vanadyl acetate (VA) nanobelts, an organic--inorganic hybrid material, are synthesized for the first time as an anode material for LIBs. As a result, the VA nanobelt electrode displays an outstanding electrochemical performance, including a highly stable reversible specific capacity (around 1065 mA h g-1 at 200 mA g-1), superior long-term cyclability (with a capacity of approximately 477 mA h g-1 at 2 A g-1 over 500 cycles) and attractive rate capability (1012 mA h g-1 when the current density recovers to 200 mA g-1). In addition, scanning electron microscopy (SEM), cyclic voltammetry (CV) curves at different scanning rates and electrochemical impedance spectroscopy (EIS) are used to investigate the variation of the specific capacity and the electrochemical kinetic characteristics of the VA electrode during cycling in detail, respectively. Also, the structural variations of the VA electrode in the initial two cycles are also investigated by in situ XRD testing. The periodic evolution of the in situ XRD patterns demonstrates that the VA nanobelt electrode shows excellent reversibility for Li+ ion insertion/extraction. This work offers an enlightening insight into the future research into organo--vanadyl hybrids as advanced anode materials. [ABSTRACT FROM AUTHOR]

A set of new generation N/O donors, maleonitrile tethered, tetradentate heteroscorpionate modified Schiff base type ligands, 2-((E)-2-hydroxybenzylideneamino)-3-(pyridin-2-ylmethylamino)maleonitrile (H2LH), 2-((E)-2-hydroxy-5-nitrobenzylideneamino)-3-(pyridin-2-ylmethylamino)maleonitrile (H2LNO2), and 2-((E)-2-hydroxy-3-methoxybenzylideneamino)-3-(pyridin-2-ylmethylamino)maleonitrile (H2LOMe) were synthesized. These ligands were reacted with a stoichiometric amount of zinc acetate to afford corresponding mononuclear Zn complexes [Zn(LH)] (1H), [Zn(LNO2)] (1NO2), and [Zn(LOMe)] (1OMe) with excellent yields. All metal complexes and ligands were fully characterized using all possible spectroscopic tools, including single-crystal X-ray structure analysis in some cases. The 1H NMR spectral feature was well explained in terms of the electronic effect of the ligand's substitution at the phenyl ring. Novel monomeric Zn complexes supported by heteroscorpionate ligands were explored as effective catalysts to convert CO2 and CS2 to cyclic carbonates and thiocarbonates, respectively, via epoxide ring opening under mild and solvent-free conditions where tetrabutylammonium bromide (TBAB) was used as co-catalyst. The synthesized catalyst activates CO2 and CS2 at ambient conditions, whereas most of the reported catalysts require harsh conditions. Electronically, the Zn center in 1H was found to have the highest Lewis acidity, enabling better catalytic activity with respect to other Zn complexes. The probable mechanisms of catalytic activity for CO2 and CS2 activation were also explained. Mechanistically, the {Zn–Br} unit serves as a Lewis acidic platform that stabilizes the activated epoxide intermediate after ring opening by bromide ion and provides suitable nucleophiles for a further attack at the CO2/CS2 center. Exclusive cyclic carbonate/thiocarbonate formation was explained as the cyclization of activated CO2/CS2 product occurring at the Zn center before it is released as an acyclic intermediate. [ABSTRACT FROM AUTHOR]

CO2 electrochemical conversion on copper electrocatalysts demonstrates selectivity and activity towards multicarbon compounds such as ethylene. However, the complex product distribution, as well as the wasted carbon and electrons in non-target products such as HCOOH, CO, and H2, can significantly increase the energy input and separation costs. As a result, we designed an electro-bio tandem reactor using copper electrocatalysts and microorganisms to transform CO2 into specific multicarbon compounds in both the gas and liquid phases. The unavoidable reducing products from electrocatalysis, including HCOOH in the liquid phase, and CO and H2 in the gas phase, can be consumed and recycled as electron donors or better carbon feedstocks for selective acetate synthesis in Moorella thermoacetica via the Wood–Ljungdahl pathway. In neutral electrolytes, the faradaic selectivity of acetate in liquid products is the highest (79.6%) for Cu-based CO2 electroreduction, and the electron conversion rate to ethylene and acetate is the highest for microbial electrosynthesis (8113.8 mmol h−1 m−2), demonstrating a green design for CO2 upcycling targeting multicarbon products via the parallel integration of electrocatalysis and fermentation. [ABSTRACT FROM AUTHOR]

In this work, a novel Cu(I)-containing metal organic framework named [CuI]-Cu-BTC was easily synthesized via incorporating Cu(I) active sites onto the surface of Cu-BTC by in situ templated electrosynthesis using an ionic liquid system as the electrolyte. Using the ionic liquid 1-ethyl-3- methylimidazolium acetate ([Emim][OAc]) as the base, the [CuI]-Cu-BTC/[Emim][OAc] system showed efficient catalytic activity for the reactions of CO2 and propargylic alcohols under mild conditions, and high yields of a-alkylene cyclic carbonates were obtained. Moreover, the [CuI]-Cu-BTC/[Emim][OAc] system could be easily separated after the reaction and reused at least five times without obvious loss of catalytic activity. The Cu(I) and [OAc]= played synergistic roles in activating the CRC and hydroxyl groups in the propargylic alcohols, resulting in the excellent performance of [CuI]-Cu-BTC/[Emim][OAc]. [ABSTRACT FROM AUTHOR]

The reaction of 2,6-diformyl-4-methylphenol, 4-methoxybenzoylhydrazine and Co(OAc)2·4H2O in 1 : 2 : 2 mole ratio in methanol under aerobic conditions produced in 61% yield a tetranuclear complex having the molecular formula [CoIICoIII(μ-OAc)(μ3-OH)(μ-L)]2 where OAc− and L3− represent acetate and N′,N′′-(5-methyl-2-oxido-1,3-phenylene)bis(methan-1-yl-1-ylidene)bis(4-methoxybenzoylhydrazonate), respectively. The elemental analysis and the mass spectrometric data confirmed the molecular formula of the complex. It is electrically non-conducting and paramagnetic. The complex crystallized as acetonitrile solvate. The X-ray structure shows that each Co(II) centre has a distorted square-pyramidal NO4 coordination sphere, while each Co(III) centre is in a distorted octahedral NO5 environment. The four metal atoms and the four bridging O-atoms form an open cubane type Co4O4 motif. In the crystal lattice, self-assembly of the solvated complex via intermolecular O–H⋯O interaction leads to a two-dimensional network structure. The infrared and electronic spectroscopic features of the complex are consistent with its molecular structure. Cryomagnetic measurements together with theoretical calculations suggest the presence of easy-axis anisotropy for the square-pyramidal Co(II) centres. The complex is redox-active and displays metal centred oxidation and reduction responses on the anodic and cathodic sides, respectively, of the Ag/AgCl electrode. Bifunctional heterogeneous electrocatalytic activity of the complex towards O2 and H2 evolution reactions (OER and HER) in neutral aqueous medium has been explored in detail. [ABSTRACT FROM AUTHOR]

meta-Substituted N-phenyl,N′-methyl and N-benzyl,N′-methyl imidazolium salts undergo acetate-assisted cyclometallation to provide mixtures of ortho and para substituted cyclometallated complexes. The effect of the substituents on the isomer ratios is discussed; steric effects are more important in the 6-membered rings derived from the N-benzyl imidazolium salts than 5-membered rings from the N-phenyl salts. Comparisons are made to steric effects with some other common directing groups. [ABSTRACT FROM AUTHOR]