429-42-5Relevant articles and documents
Electrochemical studies of the nickel catecholate complexes for detection of sulphur dioxide gas
Tembwe, Inonge,Ngila, J. Catherine,Kgarebe, Boitumelo,Darkwa, James,Iwuoha, Emmanuel
, p. 4314 - 4318 (2010)
Nickel catecholate complexes, bis(diphenylphosphino)ethanenickelcatecholate [(dppe)NiO2C6H34-R1] R1 = CH3 (1), C(CH3)3 (2), H (3) and F (4)] were studied using CV and
External oxidant-free cross-coupling: Electrochemically induced aromatic C-H phosphonation of azoles with dialkyl-: H -phosphonates under silver catalysis
Yurko,Gryaznova,Kholin,Khrizanforova,Budnikova
, p. 190 - 196 (2018)
A convenient external oxidant-free method of phosphorylation of azole derivatives (benzo-1,3-azoles, 3-methylindole, 4-methyl-2-acetylthiazole) by using dialkyl-H-phosphonates through the catalytic oxidation of their mixture under electrochemical mild conditions (room temperature, normal pressure) in the presence of silver salts or oxide (1%) is proposed. This method allows us to obtain the desired azole dialkylphosphonates with good yield (up to 75%). The transformations of silver and phosphorus precursors and intermediates using cyclic voltammetry, ESR, and NMR spectroscopy were investigated, and a radical process mechanism was proposed. It has been found that AgP(O)(OEt)2 is oxidized earlier than other components of the reaction mixture with the elimination of a radical. The ESR spectrum of this radical's adduct was obtained in the presence of the radical trap PBN. Ag2+ is out of the catalytic cycle.
Controlling Metal-to-Oxygen Ratios via M=O Bond Cleavage in Polyoxovanadate Alkoxide Clusters
Petel, Brittney E.,Fertig, Alex A.,Maiola, Michela L.,Brennessel, William W.,Matson, Ellen M.
, p. 10462 - 10471 (2019)
In this manuscript, we further investigate the use of Lindqvist polyoxovanadate alkoxide (POV-alkoxide) clusters as homogeneous molecular models of reducible metal oxides (RMO), focusing on the structural and electronic consequences of forming one or two oxygen-deficient sites. We demonstrate the reactivity of a neutral POV-alkoxide cluster, [V6O7(OCH3)12]0, with a reductant, revealing routes for controlling metal-to-oxygen ratios in self-assembled polynuclear ensembles through post-synthetic modification. The outlook of this science is bolstered by the fact that, in both cases, O-atom removal reveals reduced V ions at the surface of the cluster. Extending our entry into small-molecule activation mediated by surface defect sites, we report the reactivity of mono- and divacant clusters with a model substrate, tert-butyl isocyanide, demonstrating the electronic consequences of small-molecule coordination to reduced ions in RMO materials.
Halogen-free ionic liquids: Effect of chelated orthoborate anion structure on their lubrication properties
Gusain, Rashi,Khatri, Om P.
, p. 25287 - 25294 (2015)
In transportation vehicles, a large portion of energy is consumed to overcome friction in the engine and associated components. An efficient lubricant system has a direct impact on saving energy and material loss by reducing the friction, wear, and corrosion. Herein, halogen-free chelated orthoborate ionic liquids were designed, synthesized and then evaluated as potential lubricant additives. The effect of the orthoborate anion structure on the thermal stability, corrosion, friction, and wear properties of ionic liquids were studied. The copper strip tests revealed the non-corrosiveness of bis(mandalato)borate (BMdB), bis(salicylato)borate (BScB), and bis(malonato)borate (BMlB) anion constituted ionic liquids. Whereas, the bis(oxalato)borate (BOxB) anion, eventually developed micro-pits of corrosion owing to its lower stability and acidic nature of the decomposed product. These ionic liquids as additives to the synthetic lube base oil significantly reduced both friction and wear. The degree of friction and wear reduction was influenced by the structure of associated anions. BMdB and BScB anion constituted ionic liquids exhibited excellent thermal stability, friction-reduction, and antiwear properties, which are attributed to their compact and chemically stable structure driven by higher intermolecular interactions and rigidity of aromatic rings. The chemical analysis of tribo-interfaces suggested the formation of an ionic liquid composed tribochemical product and that enhanced the lubrication properties. Being halogen-free, these ionic liquids could be energy efficient and environmentally-friendly substitutes to the conventional friction-reducing and antiwear additives. This journal is
Assessing the Electrocatalytic Properties of the (Cp*RhIII)2+-Polyoxometalate Derivative [H2PW11O39(RhIIICp*(OH2))]3- towards CO2 Reduction
Girardi, Marcelo,Platzer, Dominique,Griveau, Sophie,Bedioui, Fethi,Alves, Sandra,Proust, Anna,Blanchard, Sébastien
, (2018)
Storage of electricity produced intermittently by renewable energy sources is a societal issue. Besides the use of batteries and supercapacitors, conversion of excess electricity into chemical energy is also actively investigated. The conversion of CO2 to fuel or fuel precursors is an option that requires the use of a catalyst to overcome the high activation energy barrier. Of molecular catalysts, metal complexes with polypyridyl ligands are well represented, among which the [Cp*Rh(bpy)Cl]+ and [M(bpy)(CO)3X] (M = Re, Mn) complexes. As redox non-innocent ligand, the bipyridine ligand is generally involved in the reduction mechanisms. It is thus tempting to replace it by other redox non-innocent ligands such as vacant polyoxometalates (POMs). We have thus prepared [α-H2PW11O39(RhIIICp*(OH2))]3- which is closely related to [Cp*RhIII(bpy)Cl]+ by substitution of the monovacant [PW11O39]7- Keggin-type POM for the bipyridine ligand. Its activity towards CO2 reduction has been assessed in acetonitrile in the presence of water. Compared to [Cp*Rh(bpy)Cl]+ that produces formate selectively over CO and H2, the POM derived catalyst favors proton reduction over CO2 reduction.
Transition-metal Complexes of Crown Ether Benzodithiolenes. Part 2. The Effects of Alkali-metal Cation Binding
Lowe, Nigel D.,Garner, C. David
, p. 3333 - 3340 (1993)
The binding of Li(+), Na(+) and K(+) cations to the crown ether rings of a series of transition-metal complexes with crown ether benzodithiolene ligands has been monitored.Fast atom bombardment mass spectrometry and UV/VIS spectroscopy have been used to demonstrate the binding of the cations to the complexes, and cyclic voltammetric studies provide a quantitative measure of the perturbations which result upon cation binding.The results support the view that the electronic transitions arise primarily from sulfur-to-metal charge-transfer transitions, provide information concerning the dithiolate(2-) or dithioketonic form of the dithiolene ligand, and indicate whether a particular redox process is primarily metal- or ligand-based.Some selectivity within the series Li(+), Na(+) and K(+) is observed, with the benzo-15-crown-5 ring showing a preference for the first two and the benzo-18-crown-6 ring preferring K(+).Tris(crown ether benzodithiolene) complexes of molybdenum and tungsten show the most promise as sensors for alkali-metal cations.
Charge-Assisted phosph(v)azane anion receptors
Bond, Andrew D.,Goodman, Jonathan M.,Lee, Sanha,Plajer, Alex J.,Wright, Dominic S.
, p. 3403 - 3407 (2020/04/02)
Coordination of Cu(i) or Pd(ii) to seleno-cyclodiphosph(v)azanes of the type [RNH(Se)P(μ-NtBu)]2 results in positively charged anion receptor units which have increased anion affinity over the neutral seleno-phosph(v)azanes, due to the increase in electrostatic interactions between the receptor and the guest anions. The same effect is produced by replacement of one of the PSe units by a P-Me+ unit.
Lewis Acidity Scale of Diaryliodonium Ions toward Oxygen, Nitrogen, and Halogen Lewis Bases
Legault, Claude Y.,Mayer, Robert J.,Mayr, Herbert,Ofial, Armin R.
supporting information, (2020/03/13)
Equilibrium constants for the associations of 17 diaryliodonium salts Ar2I+X- with 11 different Lewis bases (halide ions, carboxylates, p-nitrophenolate, amines, and tris(p-anisyl)phosphine) have been investigated by titrations followed by photometric or conductometric methods as well as by isothermal titration calorimetry (ITC) in acetonitrile at 20 °C. The resulting set of equilibrium constants KI covers 6 orders of magnitude and can be expressed by the linear free-energy relationship lg KI = sI LAI + LBI, which characterizes iodonium ions by the Lewis acidity parameter LAI, as well as the iodonium-specific affinities of Lewis bases by the Lewis basicity parameter LBI and the susceptibility sI. Least squares minimization with the definition LAI = 0 for Ph2I+ and sI = 1.00 for the benzoate ion provides Lewis acidities LAI for 17 iodonium ions and Lewis basicities LBI and sI for 10 Lewis bases. The lack of a general correlation between the Lewis basicities LBI (with respect to Ar2I+) and LB (with respect to Ar2CH+) indicates that different factors control the thermodynamics of Lewis adduct formation for iodonium ions and carbenium ions. Analysis of temperature-dependent equilibrium measurements as well as ITC experiments reveal a large entropic contribution to the observed Gibbs reaction energies for the Lewis adduct formations from iodonium ions and Lewis bases originating from solvation effects. The kinetics of the benzoate transfer from the bis(4-dimethylamino)-substituted benzhydryl benzoate Ar2CH-OBz to the phenyl(perfluorophenyl)iodonium ion was found to follow a first-order rate law. The first-order rate constant kobs was not affected by the concentration of Ph(C6F5)I+ indicating that the benzoate release from Ar2CH-OBz proceeds via an unassisted SN1-type mechanism followed by interception of the released benzoate ions by Ph(C6F5)I+ ions.
Stereoelectronic and Resonance Effects on the Rate of Ring Opening of N-Cyclopropyl-Based Single Electron Transfer Probes
Grimm, Michelle L.,Suleman, N. Kamrudin,Hancock, Amber N.,Spencer, Jared N.,Dudding, Travis,Rowshanpour, Rozhin,Castagnoli, Neal,Tanko, James M.
supporting information, p. 2640 - 2652 (2020/02/18)
N-Cyclopropyl-N-methylaniline (5) is a poor probe for single electron transfer (SET) because the corresponding radical cation undergoes cyclopropane ring opening with a rate constant of only 4.1 × 104 s-1, too slow to compete with other processes such as radical cation deprotonation. The sluggish rate of ring opening can be attributed to either (i) a resonance effect in which the spin and charge of the radical cation in the ring-closed form is delocalized into the phenyl ring, and/or (ii) the lowest energy conformation of the SET product (5a￠+) does not meet the stereoelectronic requirements for cyclopropane ring opening. To resolve this issue, a new series of N-cyclopropylanilines were designed to lock the cyclopropyl group into the required bisected conformation for ring opening. The results reveal that the rate constant for ring opening of radical cations derived from 1′-methyl-3′,4′-dihydro-1′H-spiro[cyclopropane-1,2′-quinoline] (6) and 6′-chloro-1′-methyl-3′,4′-dihydro-1′H-spiro[cyclopropane-1,2′-quinoline] (7) are 3.5 × 102 s-1 and 4.1 × 102 s-1, effectively ruling out the stereoelectronic argument. In contrast, the radical cation derived from 4-chloro-N-methyl-N-(2-phenylcyclopropyl)aniline (8) undergoes cyclopropane ring opening with a rate constant of 1.7 × 108 s-1, demonstrating that loss of the resonance energy associated with the ring-closed form of these N-cyclopropylanilines can be amply compensated by incorporation of a radical-stabilizing phenyl substituent on the cyclopropyl group. Product studies were performed, including a unique application of EC-ESI/MS (Electrochemistry/ElectroSpray Ionization Mass Spectrometry) in the presence of 18O2 and H218O to elucidate the mechanism of ring opening of 7a￠+ and trapping of the resulting distonic radical cation.
METHOD FOR PRODUCING IONIC LIQUID AND METHOD FOR PRODUCING INTERMEDIATE BODY FOR PRODUCTION OF IONIC LIQUID
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Paragraph 0117, (2018/02/22)
PROBLEM TO BE SOLVED: To provide a method for producing an ionic liquid for synthesizing a desired ionic liquid with high purity, and to provide a method for producing an intermediate body for synthesizing the ionic liquid. SOLUTION: A method for producing an ionic liquid which produces a desired ionic liquid Q+Z- formed from cation Q+ and anion Z- includes: a step of purifying a high-melting point intermediate body Q+Y- that is formed from the cation Q+ and the anion Z- and has such a melting point as to be recrystallized, by recrystallization; and a step of obtaining the ionic liquid Q+Z- directly or indirectly from the purified high-melting point intermediate body Q+Y-. A method for producing a strongly acidic intermediate body and a super-hydrophilic intermediate body includes: a step of obtaining a strongly acidic intermediate body or a super-hydrophilic intermediate body from the purified high-melting point intermediate body Q+Y- by a double decomposition precipitation method or obtaining the strongly acidic intermediate body from the purified high-melting point intermediate body Q+Y- by a double decomposition precipitation method, or a step of obtaining the super-hydrophilic intermediate body from the strongly acidic intermediate body by a neutralization method. SELECTED DRAWING: Figure 1 COPYRIGHT: (C)2018,JPOandINPIT
