Cesium Carboxylates Research Articles

Enhancing the organic solar cells performances by elevating cesium carboxylate content of graphene oxide based cathode interface layer

A strategy to enhance the carboxyl content of graphene oxide (GO) is proposed. By creating defects to obtain new edge sites on GO, the carboxyl content of the new derivative d-GO-COOH is increased from an initial 3.06% to 9.08% (at.%), while the other oxygen-containing functional groups are less than that of GO. After loading the carboxyl group with cesium (Cs), the obtained d-GO-COOCs had a higher Cs content of 6.05% (at.%). Hence a lower work function (4.14 eV) is realized compared to that of GO-COOCs (4.37 eV). The cathode interface layer (CIL) effect of d-GO-COOCs was studied in inverted organic solar cells (OSCs). A new small molecule i-IEICO-Br was designed and prepared as the electron-acceptor to match with the wide bandgap polymer donor materials (PBDB-T). In contrast to GO-COOCs-based devices, the open-circuit voltage (VOC), short-circuit current density (JSC), and fill factor (FF) of d-GO-COOCs-based devices were simultaneously improved, giving the higher power conversion efficiency (PCE) of 6.10%. The enhanced CIL characteristic of d-GO-COOCs was further confirmed in the PM6:Y6 material system. These results imply that through selective structural optimization, GO could be better adapted to the application in OSCs and would contribute to the wider use of GO-based CIL.

Inherently Chiral 6,7-Diphenyldibenzo[ e,g ][1,4]diazocine: Enantioselective Synthesis and Application as a Ligand Platform

Inherently Chiral 6,7-Diphenyldibenzo[ <i>e,g</i> ][1,4]diazocine: Enantioselective Synthesis and Application as a Ligand Platform

ChemInform Abstract: Cesium Carboxylate‐Promoted Iridium Catalyzed C—H Amidation/Cyclization with 2,2,2‐Trichloroethoxycarbonyl Azide.

An Ir(III)-catalyzed direct C-H amidation/cyclization of benzamides using 2,2,2-trichloroethoxycarbonyl azide (TrocN3) as the aminocarbonyl source is reported. With the aid of cesium carboxylate, the reactions proceed efficiently and with high regioselectivity, producing various functionalized quinazoline-2,4(1H,3H)-diones, which are important building blocks and key synthetic intermediates for biologically and medicinally important compounds. During the reactions, two new C-N bonds were formed by breaking C-H and N-H bonds sequence.

Cesium Carboxylate-Promoted Iridium Catalyzed C-H Amidation/Cyclization with 2,2,2-Trichloroethoxycarbonyl Azide.

An Ir(III)-catalyzed direct C-H amidation/cyclization of benzamides using 2,2,2-trichloroethoxycarbonyl azide (TrocN3) as the aminocarbonyl source is reported. With the aid of cesium carboxylate, the reactions proceed efficiently and with high regioselectivity, producing various functionalized quinazoline-2,4(1H,3H)-diones, which are important building blocks and key synthetic intermediates for biologically and medicinally important compounds. During the reactions, two new C-N bonds were formed by breaking C-H and N-H bonds sequence.

Carboxylate-Assisted Iridium-Catalyzed C-H Amination of Arenes with Biologically Relevant Alkyl Azides.

An iridium-catalyzed C-H amination of arenes with a wide substrate scope is reported. Benzamides with electron-donating and -withdrawing groups and linear, branched, and cyclic alkyl azides are all applicable. Cesium carboxylate is crucial for both reactivity and regioselectivity of the reactions. Many biologically relevant molecules, such as amino acid, peptide, steroid, sugar, and thymidine derivatives can be introduced to arenes with high yields and 100 % chiral retention.

Interaction between the Cesium Cation and Cesium Carboxylates: An Extended Cs+ Basicity Scale.

The interaction between the cesium cation and fulvic or humic acids is supposed to play a role in cesium mobility in the environment, which is of importance in the context of geographical dispersion or concentration of the corresponding radionuclides. Among the singly charged positive clusters generated by electrospray ionization of mixtures of carboxylic acids (AH) and cesium salts (nitrate, iodide, or trifluoroacetate), the cluster [A- Cs+ ]Cs+ [A'- Cs+ ] was subjected to collision-induced dissociation. The fragmentation into Cs+ [A- Cs+ ] and Cs+ [A'- Cs+ ] was treated using the kinetic method. A gas-phase basicity ladder was built by a step-by-step addition of the relative basicity data. The relative basicity scale deduced from the kinetic method was calibrated using the affinity and basicity (the enthalpy and Gibbs energy scales, respectively) obtained from DFT calculations. The enhanced basicity of the polyacid salts, relative to their monoacid salts, as well as the substituent effects on aliphatic and aromatic structures, are discussed.

Selective Permeation of Hydrogen Gas Using Cellulose Nanofibril Film

Biobased membranes that can selectively permeate hydrogen gas have been developed from aqueous dispersions of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofibrils (TOCN) prepared from wood cellulose: TOCN-coated plastic films and self-standing TOCN films. Compared with TOCNs with sodium, lithium, potassium, and cesium carboxylate groups, TOCN with free carboxyl groups (TOCN-COOH) had much high and selective H2 gas permeation performance. Because permeabilities of H2, N2, O2, and CO2 gases through the membranes primarily depended on their kinetic diameters, the gas permeation behavior of the various TOCNs can be explained in terms of a diffusion mechanism. Thus, the selective H2 gas permeability for TOCN-COOH was probably due to a larger average size in free volume holes present between nanofibrils in the layer and film than those of other TOCNs with metal carboxylate groups. The obtained results indicate that TOCN-COOH membranes are applicable as biobased H2 gas separation membranes in fuel cell electric power generation systems.

New approaches to hyperbranched poly(4‐chloromethylstyrene) and introduction of various functional end groups by polymer‐analogous reactions

AbstractA facile way for the synthesis of hyperbranched poly(4‐chloromethylstyrene) [P(4‐CMS)] with adjustable molar mass by classic atom transfer radical polymerization (ATRP) and mechanistically similar procedures is presented. Subsequently, the chlorine functional groups have been modified to obtain polymers with different polarities. On the one hand, the polymer was end‐capped with unpolar groups (e.g., methyl, phenol ether) to obtain chemically inert substances. On the other hand, more complex functional groups have been introduced through azide groups by 1,3‐dipolar cycloaddition reaction (“click chemistry”). Furthermore, a method for the introduction of ester groups under mild conditions using cesium carboxylates is presented, which also allowed the preparation of so‐called hyperstars by attaching COOH functionalized polystyrene chains onto the P(4‐CMS) as core molecule. All these reactions were carried out in high or very high yields. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2224–2235, 2010

Interaction of the Cesium Cation with Mono-, Di-, and Tricarboxylic Acids in the Gas Phase. A Cs+ Affinity Scale for Cesium Carboxylates Ion Pairs

Humic substances (HS), including humic and fulvic acids, play a significant role in the fate of metals in soils. The interaction of metal cations with HS occurs predominantly through the ionized (anionic) acidic functions. In the context of the effect of HS on transport of radioactive cesium isotopes in soils, a study of the interaction between the cesium cation and model carboxylic acids was undertaken. Structure and energetics of the adducts formed between Cs+ and cesium carboxylate salts [Cs+RCOO-] were studied by the kinetic method and density functional theory (DFT). Clusters generated by electrospray ionization mass spectrometry from mixtures of a cesium salt (nitrate, iodide, trifluoroacetate) and carboxylic acids were quantitatively studied by CID. By combining the results of the kinetic method and the energetic data from DFT calculations, a scale of cesium cation affinity, CsCA, was built for 33 cesium carboxylates representing the first scale of cation affinity of molecular salts. The structural effects on the CsCA values are discussed.

Quantitative analysis of free fatty acids in rat plasma using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry with meso-tetrakis porphyrin as matrix

Quantitative analysis of free fatty acids was achieved using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI–TOF MS) with a meso-tetrakis porphyrin matrix. Cesium acetate was employed as a cationizing agent. The MALDI signal was reproducible and dominated by cesiated cesium carboxylates [RCOOCs + Cs] +. The addition of two Cs ions resulted in a mass shift of 264.8 Da for each fatty acid and greatly reduced background peaks. A linear relationship between fatty acid concentration and corresponding fatty acid to internal standard peak intensity ratio was observed for three representative fatty acids analyzed across a concentration range from 4.40 to 150 μM, with correlation coefficients between 0.986 and 0.987. The application of this method was demonstrated with the analysis of free fatty acids in nonfasted and fasted rat plasmas. A total of eight free fatty acids (14:0, 16:0, 16:1, 17:0, 18:0, 18:1, 18:2, and 20:4) were detected. The relative peak height ratios of the fatty acids to the internal standard allow quantitative measurements of the free fatty acids. It was shown that the levels of free fatty acids were higher in fasted rats than in rats in a nonfasted state. This method is simple, sensitive, and fast. Thus, it provides an appealing tool for the analysis of free fatty acids or other low-molecular weight compounds during drug discovery and/or development.

Efficient Hydroxyl Inversion in Propionates via Cesium Carboxylates.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Efficient Hydroxyl Inversion in Propionates via Cesium Carboxylates

A versatile method for hydroxyl inversion, based on cesium carboxylates, was developed for polypropionate precursors and models. This procedure is compatible with a number of functional groups, including 3,4-epoxy alcohols, which tend to cyclize under basic conditions. This strategy allowed the preparation of a series of diastereomeric alcohols and new 3,4-epoxy alcohols, not available by standard iodocyclization techniques.

Structure and Properties of Butadiene-tert-Butyl Methacrylate and Butadiene/Styrene-tert-Butyl Methacrylate Triblock Copolymer Ionomers

The structure-property behavior of two series of new ionomers derived from well-defined block copolymers was investigated. The two types of triblock systems were either poly(tBMA-b-BD-b-tBMA) or poly(tBMA-b-S-t-BD-t-S-b-tBMA) (tBMA = tert-butyl methacrylate ; BD butadiene ; S = styrene ; t = taper). The materials have been examined in the tert-butyl ester forms and also hydrolyzed (carboxylic acid) and neutralized to the cesium carboxylate salt. The ester precursor exhibits a morphological transformation upon neutralization in the case of a 9 mol % tBMA-BD triblock, from unoriented rodlike domains in the ester precursor to ion-containing spheroids in the ionomer. This transformation was observed by transmission electron microscopy (TEM) and also supported by the dynamic mechanical behavior of the respective systems. The introduction of styrene into the butadiene center block results in an increase in the glass transition temperature, as anticipated. However, the tapered nature of the center block in the styrenic materials promotes greater phase mixing, as supporting TEM and dynamic mechanical analysis (DMA) indicate. The composition of the center block in these tapered materials also alters the glass transition, as shown by DMA. In the tapered SBS cesium ionomers, the temperature of the transition to flow occurs at higher temperatures as the length of the ionic end block increases.

Stereoselective Synthesis of β-1-O-Acyl Derivatives of Carbohydrates: An Application of the Cesium Effect.

The stereoselective formation of anomerically pure 1-O-acyl derivatives of protected carbohydrates is achieved by reaction of the α-glycosyl halogenoses with cesium caboxylates. The stereoselective formation of anomerically pure 1-O-acyl derivatives of protected carbohydrates is achieved by S N 2 reaction of the α-glycosylhalogenoses with cesium carboxylates.

A short highly regio- and stereoselective synthesis of triacylglycerols

Glycidyl esters reacted with carboxylic anhydrides in the presence of LiBr in tetrahydrofuran (THF) or benzene to produce 3-bromo-1,2-propanediol esters with no significant acyl migration. Displacement of Br by cesium carboxylates was accomplished cleanly in THF-hexamethylphosphoric triamide (THF-HMPT) at 50–55°C (5 h) completing a highly regioselective triglyceride synthesis. The regioselectivity of these reactions allows stereoselective synthesis if one initiates the short sequence with enantiomerically pure glycidol. Commercial ( R)-(+)-glycidol (94.6% R) was used to synthesize ( R)- and ( S)-lauroyl oleoyl palmitoyl glycerol. 1H-NMR data of S-methoxy- α-trifluoromethylphenyl acetic acid (( S)-MTPA) derivatives formed by reaction of the (S)-MTPA ester of ( R)-glycidol indicated that these reactions preserved configuration as expected.

ChemInform Abstract: REDUCTIONS OF ACTIVATED CARBONYL COMPOUNDS WITH CHIRAL‐BRIDGED 1,4‐DIHYDROPYRIDINES. AN INVESTIGATION OF SCOPE AND STRUCTURAL EFFECTS

AbstractEine Reihe chiraler verbrückter makrocyclischer 1,4‐Dihydropyridine wie (VIII), (IX) werden synthetisiert, deren Fähigkeit, Carbonylverbindungen enantioselektiv zu reduzieren, untersucht wird.

The synthesis of heliotridine and related alkaloids

An efficient synthesis of heliotridine from readily available retronecine was accomplished by nucleophilic displacement of the 7-mesylate, in the 7-mesyl-9-benzoate of retronecine with various cesium carboxylates in DMF, followed by hydrolysis. The synthetic procedure also permits the ready synthesis of a number of naturally occurring pyrrolizidine alkaloids possessing dissimilar acyl groups at C-7 and C-9.

Cesium carboxylates in dimethyl formamide. Reagents for introduction of hydroxyl groups by nucleophilic substitution and for inversion of configuration of secondary alcohols

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCesium carboxylates in dimethyl formamide. Reagents for introduction of hydroxyl groups by nucleophilic substitution and for inversion of configuration of secondary alcoholsWim H. Kruizinga, Bert Strijtveen, and Richard M. KelloggCite this: J. Org. Chem. 1981, 46, 21, 4321–4323Publication Date (Print):October 1, 1981Publication History Published online1 May 2002Published inissue 1 October 1981https://doi.org/10.1021/jo00334a055RIGHTS & PERMISSIONSArticle Views1271Altmetric-Citations129LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (440 KB) Get e-Alerts Get e-Alerts

Preparation of macrocyclic lactones by ring closure of cesium carboxylates

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPreparation of macrocyclic lactones by ring closure of cesium carboxylatesWim H. Kruizinga and Richard M. KelloggCite this: J. Am. Chem. Soc. 1981, 103, 17, 5183–5189Publication Date (Print):August 1, 1981Publication History Published online1 May 2002Published inissue 1 August 1981https://doi.org/10.1021/ja00407a039RIGHTS & PERMISSIONSArticle Views902Altmetric-Citations110LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (893 KB) Get e-Alerts Get e-Alerts