Carbonate Moiety Research Articles

Structural Study of [Sc3O4(CO2)n]+ (n = 2, 3) Complexes by Infrared Photodissociation Spectroscopy and Density Functional Calculations.

The catalytic transformation of CO2 into valuable products has garnered wide interest owing to both economic and environmental benefits, in which the chemical fixation of CO2 into carbonate structures represents a crucial step that occurs on the adsorbed catalyst surfaces. Transition metal oxides with acidic and basic active sites have exhibited potential in promoting the carbonation of weakly bound CO2 molecules. Here, the interactions between CO2 molecules and the Sc3O4+ cation in the gas phase are investigated by using infrared photodissociation spectroscopy in conjunction with quantum chemical calculations. Both end-on and various carbonate-containing configurations, including center and bridge carbonate structures, have been theoretically identified for the CO2-coordinated ion-molecule complexes. Based on the comparison between the experimental spectra and simulated spectra of low-lying isomers in the CO2 antisymmetric stretching vibrational frequency region, isomers characterized by a bridge carbonate core structure are demonstrated to be the major contributors to the observed spectra. Examination of potential energy surfaces reveals lower energy barriers and simpler reaction routes for the conversion of molecularly bound CO2 into a bridge carbonate moiety, providing reasonable explanations for their prevalence in the experiments.

Synthesis of Fluorinated Spiroindolenines by Transition Metal‐Catalyzed Indole Dearomatizations

AbstractA strategy to access fluorinated spiroindolenines has been developed, involving a selective functionalization of indoles with fluorinated moieties and subsequent catalytic dearomatization. Trifluomethylthio (SCF3), diethyl phosphono(difluoromethyl)thio (SCF2P(O)(OEt)2) and (phenylsulfonyl)difluoromethyl (CF2SO2Ph) groups were embedded at the C2 position of indole derivatives substituted with alkynes, allenes, and allyl carbonate moieties at the C3 position. A gold‐catalyzed cycloisomerization gave access to five spiroindolenines, and an enantioselective palladium catalyzed cyclization provided 10 fluorinated spirocyclic products with up to 77% ee.

Cut-insert-stitch editing reaction (CIStER) sequence for surgical chemical glycan editing

Post-synthetic surgical editing enables synthesizing diverse molecules from a common scaffold. Editing carbohydrates by inserting a foreign glycan is still a far-reaching goal for synthetic chemists. In this study, a one-pot-three-step chemical approach was employed to edit glycoconjugates. It is comprised of three steps: the first is a ‘cut’ step, cleaving one of the interglycosidic bonds and producing an intermediate that could be intercepted with 4-mercaptotoluene; second step activates the thiotolyl glycoside in the presence of an aglycon containing an orthogonally activatable ethynylcycloxyl carbonate moiety; and the third step involves ‘stitching’ by activating the carbonate donor. The cut-insert stitch-editing reaction (CIStER) is demonstrated by inserting branched and linear arabinans reminiscent of M. tuberculosis cell wall from the same designer trimannoside. Glycosylating an activated hydroxyacid (serinyl, steroidal, and lipid) after cutting the interglycosidic bond and stitching in the presence of base extendes the CIStER approach to the synthesis of glycohybrids.

Mesomorphic behaviour and photoluminescence study of novel homologous series of Schiff’s base derived from cholesteryl carbonate and thiadiazole moiety

ABSTRACT The steroidal derivatives are widely known for their ability to display a variety of mesophases, including frustrated phases, depending on the structure of the steroidal skeleton and the substituents attached. In this report, thirteen new homologues Schiff’s base derivatives were synthesised by condensing 4-formyl phenyl cholesteryl carbonate with 5-(4’-n-alkoxy phenyl)-2-amino-1,3,4-thiadiazole. All the synthesised derivatives were characterised using elemental analysis, FT-IR, 1H-NMR and 13C-NMR. Optical texture studies were carried out using a polarising optical microscope in heating and cooling cycles to examine the liquid crystalline behaviour of the synthesised compounds. The derivatives displayed a variety of mesophases, including chiral nematic (N*), twist grain boundary-A (TGBA), smectic A (SmA) and chiral smectic C (SmC*) phases. The isotropic temperature of all the compounds within the homologous series seems to decline with the increase in carbon numbers on flexible chains. The thermal behaviour of all the synthesised compounds was checked using differential scanning calorimetry and thermogravimetric analysis. All the synthesised compounds are UV-active and exhibit photoluminescence in the blue emission band with a remarkable quantum yield. The radical-scavenging activity of the synthesised mesogenic derivatives was also evaluated using the DPPH assay.

Theoretical design of durable and strong polycarbonates against photodegradation.

The photodegradation mechanism of polycarbonate (PC) was investigated by quantum chemistry, and a novel antidegradation molecular design using substituents was proposed. It was demonstrated that electron-withdrawing substituents in the phenyl moiety controlled bond alternation, leading to inhibition of the O-C bond cleavage in the carbonate moiety. These results provide a promising alternative for durable PC synthesis.

Lithium-ion batteries with fluorinated mesogen-based liquid-crystalline electrolytes: molecular design towards enhancing oxidation stability.

Two-dimensional (2D) nanostructured liquid crystals containing fluorinated cyclohexylphenyl and cyclic carbonate moieties have been developed as quasi-solid-state self-organized electrolytes for safe lithium-ion batteries. We have designed lithium ion-conductive liquid-crystalline (LC) materials with fluorine substituents on mesogens for improved oxidation stability. Computational studies suggest that the fluorination of mesogens lowers the highest occupied molecular orbital (HOMO) level of LC molecules and improves their oxidation resistance as electrolytes. The LC molecule complexed with lithium bis(trifluoromethanesulfonyl)imide exhibits smectic A LC phases with 2D ion transport pathways over wide temperature ranges. Cyclic voltammetry measurements of the fluorinated mesogen-based LC electrolytes indicate that they are electrochemically stable above 4.0 V vs. Li/Li+. Lithium half-cells composed of fluorinated LC electrolytes show higher discharge capacity and coulombic efficiency than those containing non-fluorinated analogous LC molecules. Combining molecular dynamics simulations with the experimental results, it is revealed that the fluorination of the mesogen effectively enhances the electrochemical stability of the LC electrolytes without significantly disrupting ionic conductivities and the LC order.

Polyhydroxyurethanes from Biobased Monomers and CO2: A Bridge between Sustainable Chemistry and CO2 Utilization†

Comprehensive SummaryPolyhydroxyurethanes (PHUs) have received considerable attention in the last decade as potential alternatives to traditional phosgene‐based polyurethanes (PUs). The development of suitable 5CC (five membered‐ring cyclic carbonate) precursors bearing multiple carbonate moieties (multi‐5CCs) is a key requisite for preparing PHUs by polyaddition reaction with bis‐ or polyamines. Producing sustainable PHUs from CO2‐based five‐membered cyclic carbonates (5CCs) obtained from biobased epoxides is a valuable strategy to bridge CO2 utilization and the upcycling of renewable substrates. In this context, while many multi‐5CC monomers reported in the literature are oil‐based, recent efforts have led to the development of a large variety of multifunctional 5CCs that are produced by the combination of CO2 and renewable resources such as fatty acids and vegetable oils, lignin, terpenes, and sugars. In this work, recent crucial advances (2019—2023) on PHUs prepared from bis‐ and multi‐5CCs produced from CO2 and (partially/potentially) biobased substrates are reviewed with respect to their synthesis, thermal and mechanical properties, and their recent, emerging applications.

Enantiospecific Synthesis of 1,3‐Disubstituted Allenes from Propargylic Carbonates through a Borylation‐1,2‐Elimination Process

AbstractAn array of enantioenriched vinyl boronates bearing an allylic carbonate moiety have been prepared through selective hydroboration of propargyl carbonates. Treatment of these vinyl boronates with TBAF in THF affords enantioenriched 1,3‐disubstituted allenes through a novel 1,2‐anti elimination in good yields and high enantiospecificities.

E-SCAN: Electrochemical Scanning of Carbonates, an In Situ Approach for Screening and Quantifying Inorganic Carbon in Soil.

A modified three-electrode system was utilized with a correlated ion-capture film that is functional to changes in soil carbonate moieties to determine an understudied pool of soil carbon that is vital toward holistic carbon sequestration─carbonous soil minerals (CSM). This composite sensor was tested on soils with varying carbonate contents using cyclic voltammetry, chromatocoulometry (DC-based), and electrochemical impedance spectroscopy to determine signal output as a function of increasing dose. To determine the in-field capability, a portable potentiostat device was integrated into a probe head setup that could be inserted into soil for testing. The results from these experiments showed a linearity of R2 > 0.97 and a measurable sensing range from 0.01% (100 ppm) to 1% (10 000 ppm). Therefore, a first-of-a-kind in-soil sensor system was developed for determining carbonate content in real soil samples using electrochemistry that can be tested in-field to survey the field-deployable and point-of-use capability of the system.

Cytosporin Derivatives from Arctic-Derived Fungus Eutypella sp. D-1 via the OSMAC Approach.

A chemical investigation of the Arctic-derived fungus Eutypella sp. D-1 based on the OSMAC (one strain many compounds) approach resulted in the isolation of five cytosporin polyketides (compounds 1-3 and 11-12) from rice medium and eight cytosporins (compounds 2 and 4-11) from solid defined medium. The structures of the seven new compounds, eutypelleudesmane A (1), cytosporin Y (2), cytosporin Z (3), cytosporin Y1 (4), cytosporin Y2 (5), cytosporin Y3 (6), and cytosporin E1 (7), were elucidated by analyzing their detailed spectroscopic data. Structurally, cytosporin Y1 (4) may be a key intermediate in the biosynthesis of the isolated cytosporins, rather than an end product. Compound 1 contained a unique skeleton formed by the ester linkage of two moieties, cytosporin F (12) and the eudesmane-type sesquiterpene dihydroalanto glycol. Additionally, the occurrence of cyclic carbonate moieties in compounds 6 and 7 was found to be rare in nature. The antibacterial, immunosuppressive, and cytotoxic activities of all compounds derived from Eutypella sp. D-1 were evaluated. Unfortunately, only compounds 3, 6, 8, and 10-11 displayed immunosuppressive activity, with inhibitory rates of 62.9%, 59.5%, 67.8%, 55.8%, and 68.7%, respectively, at a concentration of 5 μg/mL.

Optimization of the regioselective synthesis of mixed cellulose 3,5-dimethylphenyl and α-phenylethyl carbamate selectors as separation phases for chiral HPLC

Regioselective tritylation and carbonate aminolysis were employed in this work to synthesize cellulose 2,3-bis(3,5-dimethylphenyl carbamate)-6-(α-phenylethyl carbamate)-type chiral selectors. We evaluated and optimized the critical aspects of regioselective tritylation and detritylation at C6 of the glucopyranose units of the polysaccharide backbone. The advantage of using cellulose II in comparison to cellulose I for tritylation was analyzed and the detritylation time was determined by a fast and simple thin-layer chromatography method. Optimization of both tritylation and detritylation was accompanied by a combination of analytical techniques. Oxycarbonylation with phenyl chloroformate was used to introduce a reactive phenyl carbonate moiety at C6 of the intermediate cellulose 2,3-bis(3,5-dimethylphenyl carbamate), which was subsequently converted to the respective cellulose 6-(α-phenylethyl carbamate) derivative by aminolysis with enantiopure (R)- or (S)-α-phenylethylamine. The starting material, intermediates, and target cellulose derivatives were comprehensively analytically characterized by ATR-FTIR, solid- and liquid-state 13C NMR, GPC, and elemental analysis. With the optimized protocol, it became possible to obtain cellulose carbamate-type chiral selectors through carbonate aminolysis with simple and commercially available primary amines instead of reaction with isocyanate reagents. The enantioseparation performance of the obtained chiral selectors was evaluated against cellulose tris(3,5-dimethylphenyl carbamate) as a reference selector with a selection of chiral analytes.Graphical abstract

Oleochemical carbonates: A comprehensive characterization of an emerging class of organic compounds

Dialkyl carbonates (DAC) with short-medium alkyl length - oleochemical carbonates – are attracting attention because of their appealing properties, including low viscosity, flammability, toxicity, environmental impact and wide range of applications: lubricants, personal care, fuel additives etc. However, not much is known concerning their chemical physical properties and, more importantly, on the nature of microscopic correlations that eventually determine bulk performances. In view of this paucity, we present a large exploration of a series of chemical physical properties of a set of DACs ranging from dimethyl up to didodecyl carbonate. This study extends previously determined databases, thus providing a complete picture of the temperature dependence of chemical physical properties around room temperature. Furthermore, we explored the microscopic morphology of DACs, by synergic exploitation of X-ray scattering and Molecular Dynamics techniques. These tools allow detecting the existence of a distinct degree of mesoscopic spatial segregation between polar carbonate moieties and apolar alkyl chains domains. The role of first neighbour carbonate moieties in driving the corresponding molecules towards weak hydrogen bonding interactions and alkyl chain alignment is described. Such an effect is related to the overall mesoscopic segregation of alkyl tails that isolate small droplets formed by stacked carbonate groups. Such a highly compartmentalised morphology can explain and potentially suggest applications of DACs in fields as relevant as separation, catalysis, lubrication etc.

Synthesis by carbonate aminolysis and chiral recognition ability of cellulose 2,3-bis(3,5-dimethylphenyl carbamate)-6-(α-phenylethyl carbamate) selectors

Novel chiral selectors based on cellulose 2,3-bis(3,5-dimethylphenyl carbamate)-6-(α-phenylethyl carbamate) were regioselectively synthesized by carbonate aminolysis and isocyanate chemistry. By oxycarbonylation with phenyl chloroformate, carbamoylation with 3,5-dimethylphenyl isocyanate, and subsequent aminolysis of the previously introduced reactive carbonate moiety at C6 with enantiopure (R)-or (S)-α-phenylethylamine, chiral selectors have been obtained, which regioselectively carry two different phenyl carbamate substituents. The cellulose derivatives were comprehensively characterized by ATR-FTIR, solid-state NMR, GPC, and elemental analysis. In parallel, 3-aminopropyl-functionalized silica gel as an inert carrier material for the chiral selectors was prepared and the obtained coated-type chiral stationary phases were characterized by both solid-state 29Si NMR, 13C NMR, and elemental analysis. The enantioseparation performance of the chiral selectors was studied and compared to cellulose tris(3,5-dimethylphenyl carbamate) as a reference. With this protocol in hand, certain shortcomings of conventional approaches towards the regioselective synthesis of polysaccharide-based chiral selectors were overcome, such as the limitation to standard isocyanate reagents, being able to apply now the whole wealth of commercially available (chiral) primary and also secondary alkylamines instead.Graphical abstract

Electrochemical Sensor Mediated Assessment of Carbonate Moieties in Soil Matrix

Carbon sequestration is a major global phenomenon that is particularly relevant now with the effect of climate change monitoring and regenerative agriculture. It refers to different practices that contribute to the absorption and storage of carbon in the soil. While the impact of sequestration of carbon is majorly from organic sources, the effect from soil inorganic carbon accumulation is not trivial especially in arid and semi-arid regions where the inorganic carbon (IC) share in sequestration is significant. Movement of Atmospheric Carbon Dioxide (CO2) into soil resources via photosynthesis and root respiration with the subsequent formation of bicarbonate in soil, which exists as bicarbonate in solution phase in groundwater sources or precipitates into CaCO3 in soil phase. Current soil carbon monitoring is either based on extensive soil sampling for analyzing in the laboratory or using proximal sensing methods, which are less accurate. Thus, implementation of novel soil sensors for accurate in-situ measurements could fundamentally improve soil carbon assessment and monitoring. Comparatively, the level and depth of assessing inorganic carbon in soil is significantly lower than that of soil organic carbon (SOC) monitoring. Electrochemistry as a transduction mode is highly viable in this regard due to its ease of applicability in various environments including the complex-soil matrix is a vital component that holds together the Earth’s ecosystem. The key mechanism of releasing the inorganic carbon relies on capturing the different pools that encompass the inorganic/ mineral carbon in soil including- carbonate ions in soil from Calcium (Calcite) which is the major pool of the IC in soil contributing to around 90% of this source and Magnesium (Dolomite). The other minor fraction that is present in the IC pool arises from Bicarbonates (HCO3-).In this sensor development study, we have designed a modified 3-electrode system which is functionalized with a correlated ion-capture film that is functional to changes in carbonate moieties in the soil electrolyte test system. Then this composite sensor was introduced into test soil setups with varying carbonate content to measure the sensor response- wherein, cyclic voltammetry (DC based) and Electrochemical Impedance Spectroscopy was used to determine signal output as a function of increasing dose. It was seen that the peak current around 0.4-0.5V on the positive axis was modulated to increase with carbonate content (% or ppm) and correspondingly- changes in the Rct (charge-transfer resistance) and Zw (Warburg impedance) along with the capacitive element shift was noticeable in the EIS spectra. The experimental cycle was performed using an in-house designed portable potentiostat device which was integrated into a probe head setup that could be inserted into soil for testing. The results from these experiments yielded linearity metrics from regression fits as R2 > 0.97 and measurable sensing range from 0.01% (100 ppm) to 1% (10,000 ppm). Therefore, a first-of-a-kind sensor system was developed for determining carbonate content in real soil samples using an electrochemical mode which will be subsequently tested in-field to survey field deployable and point-of-use capability of the system. Figure 1

Facile Deoxygenative Reduction of a Bridging Carbonato Ligand with Silyl and Boryl 4,4’‐Bipyridinylidene Reagents

AbstractThe reactivity of CO2 with a previously described PCcarbeneP cobalt(I) hydroxide is reported. Insertion of CO2 into the Co−OH bond followed by a dehydration reaction releasing water results in a cobalt(I) bridging carbonate species featuring fluctional κ1: κ1 and κ1: κ2 coordination of the central carbonate moiety. The reduction chemistry of the resulting cobalt(I) bridging carbonate species is explored utilizing deoxygenative reducing agents N,N′‐bis(trimethylsilyl)‐ and N,N′‐bis(pinacolatoboryl)‐4,4′‐bipyridinylidene. The three‐electron reduction produces the corresponding PCcarbeneP cobalt(I) siloxide or boroxide complex alongside a PCcarbeneP cobalt(0) monocarbonyl, silyl/boryl ether, and 4,4’‐bipyridine.

Environmentally Friendly Synthesis of Urea-Free Poly(carbonate-urethane) Elastomers

This work presents an eco-friendly synthetic pathway toward non-isocyanate poly(carbonate-urethane)s (NIPCUs) obtained from carbon dioxide and its simple derivatives─organic carbonates. Bis(hydroxyalkyl carbamate)s synthesized from ethylene carbonate and appropriate α,ω-diamines were used as polyurethane hard segment precursors while oligocarbonate diols as soft segment ones. The structures and properties of the obtained NIPCUs were explored by means of 1H NMR, 13C NMR, and FT-IR spectroscopies, MALDI-ToF mass spectrometry, DSC, and mechanical testing. Based on spectroscopic data as well as model reactions, it was demonstrated that the formation of the urea bonds was suppressed due to the presence of carbonate moieties. The reaction of urea bonds with carbonate residues led to urethane group formation. In addition, the influence of the polyurethane structure on the mechanical and thermal properties of the obtained polymers was studied. The obtained NIPCUs exhibited mechanical properties comparable to conventional polyurethane elastomers (e.g., a tensile strength of 32 MPa and an elongation at break of 800%). The described synthetic route is an straightforward way toward the replacement of conventional polyurethanes with environmentally friendly ones.

UV-Cured Semi-Interpenetrating polymer networks of solid electrolytes for rechargeable lithium metal batteries

Electric vehicles and portable electronics pose an insatiable demand for safe and high-energy batteries. Herein, we report semi-interpenetrating solid state polymer networks electrolytes (SISPEs) for rechargeable lithium metal batteries. The synthesized SISPEs combine the poly(vinylethylene carbonate) (PVEC) segment containing carbonate moieties and the high molecular weight poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) with good mechanical properties. The carbonate moieties in the PVEC segment enable high ionic conductivity of 1.03 mS cm−1 at 25 0C. The incorporation of PVDF-HFP into the semi-interpenetrating polymer networks endows SISPEs with considerable mechanical properties and long-term stability of the symmetric Li cell at a current density of 0.2 mA cm−2 for over 2000 h. As a result, the assembled LiFePO4||SISPEs||Li batteries exhibit excellent cycling performance with high coulombic efficiency over 600 cycles at 0.5C. This study sheds light on rational design of high-performance composite polymeric electrolytes for rechargeable solid lithium metal batteries.

Therapeutic Stomatocytes with Aggregation Induced Emission for Intracellular Delivery.

Bowl-shaped biodegradable polymersomes, or stomatocytes, have much potential as drug delivery systems, due to their intriguing properties, such as controllable size, programmable morphology, and versatile cargo encapsulation capability. In this contribution, we developed well-defined therapeutically active stomatocytes with aggregation-induced emission (AIE) features by self-assembly of biodegradable amphiphilic block copolymers, comprising poly(ethylene glycol) (PEG) and AIEgenic poly(trimethylene carbonate) (PTMC) moieties. The presence of the AIEgens endowed the as-prepared stomatocytes with intrinsic fluorescence, which was employed for imaging of cellular uptake of the particles. It simultaneously enabled the photo-mediated generation of reactive oxygen species (ROS) for photodynamic therapy. The potential of the therapeutic stomatocytes as cargo carriers was demonstrated by loading enzymes (catalase and glucose oxidase) in the nanocavity, followed by a cross-linking reaction to achieve stable encapsulation. This provided the particles with a robust motile function, which further strengthened their therapeutic effect. With these unique features, enzyme-loaded AIEgenic stomatocytes are an attractive platform to be exploited in the field of nanomedicine.

A highly selective turn-on fluorescence probe with large Stokes shift for detection of palladium and its applications in environment water and living cells

Nowadays, palladium has been widely used in many fields, which facilitates all aspects of our life. However, it may cause water and soil pollution and bring irreversible damage to the environment and organisms. Developing a fluorescence probe for rapid, highly sensitive and selective detection of palladium is still a poser. In this work, we designed and synthesized a novel fluorescence probe (RHS) for specific detection of palladium. Based on Pd0-mediated Tsuji-Trost reaction, the fluorescence probe was constructed by a rhodol derivative as thefluorophore and an allyl carbonate moiety as the specific palladium reactive site. The probe displayed excellent properties for detecting palladium, such as high selectivity and sensitivity, rapid response (20 min) and large Stokes shift (155 nm). The detection limit was determined to be as low as 0.140 μM with a linear range from 20 to 80 μM. After addition of palladium in RHS solution, the color of the solution turned from yellow to blue, indicating palladium could be monitored by the naked eyes. Moreover, probe RHS was successfully applied to palladium detection in environmental water samples. Importantly, with low cytotoxicity and good biocompatibility, the probe could monitor palladium in living cells.

Calculations on the Ruthenium-Catalyzed Diene and Dienyne Ring-Closing Metathesis Reactions in the Synthesis of Taxol Derivatives.

Density-functional and semiempirical calculations (M06, M06L, and PM6) on intermediates in the ring-closing metathesis (RCM) reactions in the synthesis of Taxol derivatives give results in excellent agreement with the results of previous experimental work. The results suggest that the degree of steric overloading plays a decisive role in determining the outcome (ene-ene or ene-yne-ene metathesis). Due to the rigidity of the Taxol skeleton being formed in the ene-yne-ene cascade reaction, the transition states in its final ene-ene metathesis reaction stage are particularly sensitive to steric effects. Thus, the reaction is predicted to be preferred for one diastereomer of the precursor in which the diol functionality is protected with a compact cyclic carbonate moiety, whereas the use of a bulkier benzoate-protecting group results in activation barriers for Taxol formation that are prohibitive. The reason why one diastereomer of the carbonate-protected precursor undergoes formation of a tricycle via an ene-yne-ene RCM cascade, whereas the other diastereomer undergoes cyclooctene formation via an ene-ene RCM, likely lies in the orientation of the pseudoaxial methyl group on the cyclohexene ring, which in the latter case would unfavorably point toward the reactive center of the Ru-complex, leading to Taxol formation.