Triple-bonded Compounds Research Articles

ИСПОЛЬЗОВАНИЕ ОРГАНИЧЕСКИХ СОЕДИНЕНИЙ, СОДЕРЖАЩИХ ТРОЙНУЮ СВЯЗЬ С≡С, В ПРОЦЕССЕ ЭЛЕКТРОХИМИЧЕСКОГО НИКЕЛИРОВАНИЯ

The influence of the structure of organic compounds, as well as the presence of double and triple bonds on the process of brilliant electrochemical nickel plating is considered. It is shown that triple-bonded compounds are effective additives for the electrochemical production of shiny nickel coatings

Activation of Small Molecules by Compounds that Contain Triple Bonds Between Heavier Group-14 Elements.

Dimetallynes (RE≡ER; E=Si, Ge, Sn, Pb), i.e., systems that contain triple bonds between heavier group-14 elements represent the heavier homologues of alkynes. The high reactivity of disilynes, digermynes, distannynes, and diplumbynes can be interpreted in terms of their unique bonding situation, which includes a trans-bent structure, a small HOMO-LUMO gap, a partial diradical character, their electronic nature, and interactions between bulky substituents. Relatively recent developments in the area of sterically demanding substituents have permitted isolating some stable compounds with a triple bond between heavier group-14 elements. The structural features of these triple-bonded compounds and their reactivity toward small molecules have been investigated using experimental and theoretical approaches. This review focuses on recent developments regarding the reactivity of stable compounds with a triple bond between heavier group-14 elements toward small molecules, where the results were examined using quantum chemical methods. A comprehensive review on carbon chemistry is beyond the scope of this focus review.

Electrochemical Analysis the influence of Propargyl Methanesulfonate as Electrolyte Additive for Spinel LTO Interface Layer

Propargyl methanesulfonate (PMS) is chosen as an electrolyte additive to study the interfacial performance between the electrolyte and spinel lithium titanate (Li4Ti5O12, LTO) electrode. The result displays that PMS can improve cyclability of Li/LTO cell. Very interestingly, a solid electrolyte interface (SEI) film is formed above 1.0V in the voltage range of 3.0–0V. The observations are explained in terms of PMS include triple-bonded compounds and SO3. The triple-bonded compounds were able to produce a characteristic SEI with dense and low impedance, which can effectively suppress the decomposition of electrolyte, HF generation and LiF formation upon cycling. The SO groups may acts as the weak base site to hinder the reactivity of PF5. Accordingly, the incorporation of PMS into the electrolyte can remarkably enhance the cyclic performance of the Li/LTO cell.

Theoretical study on the mechanism of the cycloaddition reaction between ketenimine and hydrogen cyanide

The cycloaddition reaction mechanism between interstellar molecules ketenimine and HCN has been investigated employing the second-order M?ller-Plesset perturbation theory (MP2) method in order to better understand the reactivity of nitrogenous cumulene ketenimine with carbon-nitrogen triple bond compound HCN. Geometry optimizations and vibrational analyses have been performed for the stationary points on the potential energy surfaces of the system. The calculated results show that it can be produced the five-membered cyclic carbene intermediates through pericyclic reaction processes between ketenimine and HCN. Through the following H-transfer processes, carbene intermediates can isomerize to the pyrazole and imidazole compounds, respectively. The present study is helpful to understand the formation of prebiotic species in interstellar space.

Spectroscopic and stability studies on unsymmetrical 1,3-dialkyl-1,3-diphosphacyclobutane-2,4-diyls

Air-tolerant 2,4-bis(2,4,6-tri-t-butylphenyl)-1,3-diphosphacyclobutane-2,4-diyl singlet biradicals can be prepared by utilizing the unique reactivity of a kinetically stabilized P≡C triple bond compound. In this procedure, we studied the spectroscopic properties of a fundamental unsymmetrical P-heterocyclic biradical containing both PEt and PMe moieties, and the effects of the PCH2OMe group in relation to the stability of the P-heterocyclic biradical skeleton. The experimentally observed nuclear magnetic resonance and photo-absorption parameters of 1-ethyl-3-methyl-2,4-bis(2,4,6-tri-t-butylphenyl)-1,3-diphosphacyclobutane-2,4-diyl were discussed based on our previous findings and density functional theory calculations, suggesting particular structural characteristics of the P-heterocyclic biradical skeleton and aromatic substituent effects on the sp2-C atoms in the 4-membered ring. Introduction of the methoxymethyl group in the P2C2 biradical moiety gave more stabilized 1,3-diphosphacyclobutane-2,4-diyl derivatives. In comparison with considerably unstable biradicals bearing propargyl substituents, relatively higher lowest unoccupied molecular orbital energies suggest reluctant oxidation of the P-heterocyclic skeleton. Copyright © 2011 John Wiley & Sons, Ltd.

Synthesis of (−)-Cephalosporolide D Using an Iterative Acetylene–Epoxide Coupling Strategy

Abstract The synthesis of an eight-membered lactone, cephalosporolide D is described using an iterative acetylene–epoxide coupling strategy. The terminal triple bond compound prepared in situ from the known epoxy chloride was coupled with (R)-methyloxirane to afford the propargyl alcohol. The selective protection of the propargylic hydroxy group as TBS ether followed by reduction of the triple bond gave the saturated alcohol. Removal of THP group followed by selective oxidation of the primary hydroxy group was achieved using BAIB–TEMPO to furnish the aldehyde, which was converted to the corresponding acid by Pinnick oxidation, followed by Yamaguchi lactonization and finally removal of the TBS group afforded the target molecule. A concise synthesis of (−)-cephalosporolide D is described. The salient features are the utilization of acetylene–epoxide coupling strategy and Yamaguchi lactonization.

Functional electrolytes: Synergetic effect of electrolyte additives for lithium-ion battery

We have found that certain combinations of specific additives show a very interesting behavior in Li-ion batteries. During the course of investigating further improvements in the performance of the triple-bonded compounds, which we very recently reported, a novel and unique effect of an additive combination was observed. The combination of the triple-bonded compounds and the double-bonded compounds has proven to show a much improved battery performance, especially in cycleability and gas evolution than the case when they are singly used. Especially, the synergetic effect of propargyl methanesulfonate and vinylene carbonate is remarkable. To clarify the synergetic effect, the electrochemical properties of the additives and the electrode analyses were investigated. It is assumed that the higher battery performance of the combination effect resulted not only from the thin and dense SEI on the negative electrode but also from the positive electrode surface co-polymerized film produced by the synergetic decomposition of the additives. We suggest that the keys for producing the synergetic functions are (1) a structural difference in the unsaturated moiety, and (2) a greater difference in the reduction potential.

Functional Electrolytes: Triple-Bonded Compound as an Additive for Negative Electrode

We have found that certain triple-bonded compounds show a very interesting behavior in Li-ion batteries. These novel types of additives have proven to improve battery performance, especially in cycleability. Propargyl methanesulfonate and propargyl methyl carbonate show good performance among several triple-bonded compounds. These triple-bonded compounds are investigated in contradistinction with previously known double-bonded compounds (allyl methanesulfonate and allyl methyl carbonate). We used molecular orbital calculations for the selection of the additives and have proved that the calculated lowest unoccupied molecular orbital and highest occupied molecular orbital values agree well with the measured reduction and oxidation potentials, respectively. To clarify the performance of the triple-bonded compounds, electrochemical properties and cycleability were investigated. The triple-bonded compounds were found to be deliberately decomposed on the negative electrode to produce a dense solid electrolyte interphase (SEI), showing an excellent improvement of cycleability. The nature and the component of the derived SEI were studied by X-ray photoelectron spectroscopy and Auger electron spectroscopy. It was concluded that these triple-bonded compounds contribute to the improved cycleability, because the SEI derived from the triple-bonded compounds has a thinner and denser morphology than previously known additives.

Reaction Mechanism of Cathodic Crossed Coupling of Acetone with Unsaturated Compounds in Acidic Solution

Abstract It was confirmed that the cathodic crossed coupling of acetone with unsaturated compounds in aqueous sulfuric acid could proceed smoothly, when the compounds which had radical-acceptable double bonds and were adsorbed on a mercury cathode were used. From this fact, it was concluded that the coupling occurs via the addition of a radical intermediate formed by the one-electron reduction of acetone to the double bonds on the cathode surface. Possibility of the addition of an anionic intermediate derived from acetone was excluded by no occurrence of the coupling of acetone with a polar acetylenic triple bond compound adsorbed on the cathode.

Dielectric dispersion studies of some unsaturated compounds in dilute solutions

The dielectric permittivity and dielectric loss of solutions of four unsaturated triple-bonded compounds were measured as a function of frequency (10 kHz, 8.43, 11.3 and 35.6 GHz), temperature (33–70 °C) and concentration (0.07–0.01 weight fraction). The data are analysed in terms of a double relaxation process. The most probable relaxation time, the overall molecular relaxation time and the group relaxation time were calculated. The dipole moments were also calculated along with the thermodynamic parameters. The results are discussed in terms of association effects in these compounds and the dielectric data are correlated with the infrared spectral data.

Molecular effects in the energy loss of alpha particles in gaseous media

Abstract Previous measurements in gaseous hydrocarbon and carbon-oxygen compounds in the range 0.3 ≦ E α ≦ 2.0 MeV revealed that the Bragg additive rule failed to give molecular stopping cross sections e α from the measured atomic solid carbon stopping cross section e(C) and diatomic e expt (H 2 ) or e expt (o 2 ). For example, when hydrogen was present in the compound, the molecular data could be fitted either by using e(C) and an e'(H) which was higher than 1 2 e expt (H 2 ) by as much as 21%, or by using 1 2 e expt (H 2 ) and another e'(C) which was greater than e(C) by as much as 22%. A similar difficulty has also been encountered in interpreting the stopping cross sections recently measured for C-H-F and C-H-O compounds. e(C), e expt (H 2 ) and e expt (O 2 ) can be used to fit (CH 3 ) 2 O, but it is necessary to use e'(C) and e expt (H 2 ) for C 2 H 2 F 2 . Nevertheless, a closer examination of the stopping cross sections for eight hydrocarbon compounds reveals a correlation between the stopping cross sections of atomic hydrogen and carbon which are required to satisfy the Bragg rule, and the type of bond associated with the atomic carbon in the molecule. The stopping cross section of a carbon atom is greater when the atom is bound by a triple bond than a single bond, whereas that of a hydrogen atom is less in a triple-bond compound than in a single-bond compound. Double-bonded compounds yield a carbon stopping cross section between the single-bond and triple-bond values at lower energies and closer to the triple-bond values at higher energies.

Biological Specificities of 4,5-Dehydro Analogues of Isoleucine and Alloisoleucine

The synthesis of 2-amino-3-methyl-4-pentynoic acid with a configuration corresponding to alloisoleucine has been reported (4), and a partial hydrogenation of this compound would afford a method of obtaining w-dehydroalloisoleucine. However, in the method of synthesis of 2-amino-3-methyl-4-pentynoic acid herein reported, a mixture of both of the diastereoisomeric forms of the acetylenic derivatives was obtained. Subsequent fractional recrystallization of the mixture separated the isomers into the two racemic forms. Partial hydrogenation of the appropriate triple bond compound produced either w-dehydroisoleucine or w-dehydroalloisoleucine, and complete hydrogenation yielded the anticipated nn-isoleucine or nn-alloisoleucine. The ethylenic analogues are more effective growth inhibitors than the acetylenic deriviatives for Escherichia coli, but for Lactobacillus arabinosus the relative inhibitory activity depends upon whether the antagonism of isoleucine or of valine is being determined. Under appropriate conditions, antagonism of both isoleucine and valine by these analogues can be demonstrated with both organisms.