19740-81-9Relevant academic research and scientific papers
Electronic structure and catalytic aspects of [Ru(tpm)(bqdi)(Cl/H 2O)]n, tpm = tris(1-pyrazolyl)methane and bqdi = o-benzoquinonediimine
Agarwala, Hemlata,Ehret, Fabian,Chowdhury, Abhishek Dutta,Maji, Somnath,Mobin, Shaikh M.,Kaim, Wolfgang,Lahiri, Goutam Kumar
, p. 3721 - 3734 (2013)
The diamagnetic complexes [Ru(tpm)(bqdi)(Cl)]ClO4 ([1]ClO 4) (tpm = tris(1-pyrazolyl)methane, bqdi = o-benzoquinonediimine) and [Ru(tpm)(bqdi)(H2O)](ClO4)2 ([2](ClO 4)2) have been synthesized. The valence state-sensitive bond distances of coordinated bqdi [C-N: 1.311(5)/1.322(5) A in [1]ClO4; 1.316(7)/1.314(7) A in molecule A and 1.315(6)/1.299(7) A in molecule B of [2](ClO4)2] imply its fully oxidised quinonediimine (bqdi0) character. DFT calculations of 1+ confirm the {RuII-bqdi0} versus the antiferromagnetically coupled {RuIII-bqdi-} alternative. The 1H NMR spectra of [1]ClO4 in different solvents show variations in chemical shift positions of the NH (bqdi) and CH (tpm) proton resonances due to their different degrees of acidity in different solvents. In CH3CN/0.1 mol dm-3 Et4NClO 4, [1]ClO4 undergoes one reversible RuII ? RuIII oxidation and two reductions, the reversible first electron uptake being bqdi based (bqdi0/bqdi-). The electrogenerated paramagnetic species {RuIII-bqdi0}(1 2+) and {RuII-Q-}(1) exhibit Ru III-type (12+: = 2.211/Δg = 0.580) and radical-type (1: g = 1.988) EPR signals, respectively, as is confirmed by calculated spin densities (Ru: 0.767 in 12+, bqdi: 0.857 in 1). The aqua complex [2](ClO4)2 exhibits two one-electron oxidations at pH = 7, suggesting the formation of {RuIVO} species. The electronic spectral features of 1n (n = charge associated with the different redox states of the chloro complex: 2+, 1+, 0) in CH3CN and of 22+ in H2O have been interpreted based on the TD-DFT calculations. The application potential of the aqua complex 2 2+ as a pre-catalyst towards the epoxidation of olefins has been explored in the presence of the sacrificial oxidant PhI(OAc)2 in CH2Cl2 at 298 K, showing the desired selectivity with a wide variety of alkenes. DFT calculations based on styrene as the model substrate predict that the epoxidation reaction proceeds through a concerted transition state pathway.
Iron-Catalyzed Epoxidation of Linear α-Olefins with Hydrogen Peroxide
Beller, Matthias,Budweg, Svenja,Junge, Kathrin,Li, Yong-Wang,Mao, Shuxin,Spannenberg, Anke,Wen, Xiaodong,Yang, Yong
, (2022/01/26)
The combination of Fe(OTf)2 with N-methyl bis(picolylamine) (Me-bpa) L7 enables epoxidation of linear olefins including terminal, internal, and cyclic ones, using hydrogen peroxide as terminal oxidant under mild conditions. In the presence of picolinic acid as additive improved yields of epoxides up to 75 % have been achieved.
Olefin epoxidation with ionic liquid catalysts formed by supramolecular interactions
Ding, Bingjie,Hou, Zhenshan,Li, Difan,Ma, Wenbao,Yao, Yefeng,Zhang, Ran,Zheng, Anna,Zhou, Qingqing
, (2020/12/29)
This work demonstrated that the specific ionic liquids (ILs) have been designed via the supramolecular complexation between 18-crown-6 (CE) and ammonium peroxoniobate (NH4-Nb). The resultant ILs have been characterized by elemental analysis, FT-IR, Raman, NMR, DSC, conductivity measurement and MALDI-TOF, etc. The IL (CE-1) consisting of CE and ammonium peroxoniobate can be further coordinated with GLY to generate a new IL (CE-2), which showed both high catalytic activity in epoxidation with H2O2 and good recyclability. The characterization of 93Nb NMR spectra revealed that the peroxoniobate anions has demonstrated a structural evolution in the presence of hydrogen peroxide, in which Nb[dbnd]O species can be easily oxidized into the catalytically active niobium?peroxo species. Especially, the supramolecular complexation can provide suitable hydrophobicity, which ensured that the hydrophobic olefins and allylic alcohols were easily accessible to the catalytically active anions, and thus facilitated the epoxidation reaction. Notably, the supramolecular IL catalysts in this work exhibited a huge advantage of the easy availability, as compared with the previously reported peroxoniobate-based ILs. As far as we know, this is the first example of the highly selective epoxidation of olefins and allylic alcohols by using supramolecular ILs as catalysts.
Efficient and region-selective conversion of octanes to epoxides under ambient conditions: Performance of tri-copper catalyst, [Cu3I(L)]+1 (L=7-N-Etppz)
Krupadam, Reddithota J.,Nagababu, Penumaka,Paul, Perala Sudheer,Reddy, Thatiparthi Byragi
, p. 742 - 745 (2021/09/28)
In this paper, is described the conversion of the octane group of hydrocarbons into industrially important epoxides using tri-copper catalyst, [Cu3I(L)]+1 (L=7-N-Etppz). The role of hydrogen peroxide as a sacrificial oxygen donor during catalytic conversion to epoxides has been investigated. The performance of the catalyst has been evaluated in terms of turnover numbers (TON) and turnover frequencies (TOF) reported in this article.
2,4,4,6,8,8-Hexanitro-2,6-diazaadamantane: A High-Energy Density Compound with High Stability
Zhang, Jian,Hou, Tianjiao,Zhang, Lin,Luo, Jun
supporting information, p. 7172 - 7176 (2018/11/25)
A novel high-performance energetic compound of the polynitroazaadamantane family, 2,4,4,6,8,8-hexanitro-2,6-diazaadamantane, was designed and synthesized from 1,5-cyclooctadiene by two routes. Based on the experimental and calculated results, it exhibits a surprisingly high density (1.959 g cm-3), high thermal stability (onset decomposition temperature of 235 °C), high positive heat of formation, and excellent detonation properties. These fascinating properties, which are comparable to those of CL-20, show great promise for potential applications as a high-energy density material.
Electronic Structure and Multicatalytic Features of Redox-Active Bis(arylimino)acenaphthene (BIAN)-Derived Ruthenium Complexes
Singha Hazari, Arijit,Ray, Ritwika,Hoque, Md Asmaul,Lahiri, Goutam Kumar
, p. 8160 - 8173 (2016/08/24)
The article examines the newly designed and structurally characterized redox-active BIAN-derived [Ru(trpy)(R-BIAN)Cl]ClO4 ([1a]ClO4-[1c]ClO4), [Ru(trpy)(R-BIAN)(H2O)](ClO4)2 ([3a](ClO4)2-[3c](ClO4)2), and BIAO-derived [Ru(trpy)(BIAO)Cl]ClO4 ([2a]ClO4) (trpy = 2,2′:6′,2′′-terpyridine, R-BIAN = bis(arylimino)acenaphthene (R = H (1a+, 3a2+), 4-OMe (1b+, 3b2+), 4-NO2 (1c+, 3c2+), BIAO = [N-(phenyl)imino]acenapthenone). The experimental (X-ray, 1H NMR, spectroelectrochemistry, EPR) and DFT/TD-DFT calculations of 1an-1cn or 2an collectively establish {RuII-BIAN0} or {RuII-BIAO0} configuration in the native state, metal-based oxidation to {RuIII-BIAN0} or {RuIII-BIAO0}, and successive electron uptake processes by the α-diimine fragment, followed by trpy and naphthalene π-system of BIAN or BIAO, respectively. The impact of the electron-withdrawing NO2 function in the BIAN moiety in 1c+ has been reflected in the five nearby reduction steps within the accessible potential limit of -2 V versus SCE, leading to a fully reduced BIAN4- state in [1c]4-. The aqua derivatives ({RuII-OH2}, 3a2+-3c2+) undergo simultaneous 2e-/2H+ transfer to the corresponding {RuIV-O} state and the catalytic current associated with the RuIV/RuV response probably implies its involvement in the electrocatalytic water oxidation. The aqua derivatives (3a2+-3c2+) are efficient and selective precatalysts in transforming a wide variety of alkenes to corresponding epoxides in the presence of PhI(OAc)2 as an oxidant in CH2Cl2 at 298 K as well as oxidation of primary, secondary, and heterocyclic alcohols with a large substrate scope with H2O2 as the stoichiometric oxidant in CH3CN at 343 K. The involvement of the {RuIV-O} intermediate as the active catalyst in both the oxidation processes has been ascertained via a sequence of experimental evidence.
METHOD FOR PRODUCING EPOXY COMPOUND AND CATALYST COMPOSITION FOR EPOXIDATION REACTION
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Paragraph 0491; 0492; 0493; 0494; 0495, (2015/02/18)
A method of producing an epoxy compound, which comprises reacting hydrogen peroxide with a compound having a carbon-carbon double bond, in the presence of at least one of a tungsten compound and a molybdenum compound; and an onium salt comprising 20 or more carbon atoms and one or more of substituents convertible to a functional group containing an active hydrogen or a salt thereof.
Epoxidation of strained alkenes catalysed by (1,2-dimethyl-4(1H)pyridinone-3-olate)2MnIIICl
Robinson-Miller, Adam P.,Wyatt, Mark F.,Tétard, David
, p. 376 - 390 (2015/01/30)
The mild epoxidation of strained alkenes using (DMPO)2MnCl catalyst (DMPO = 1,2-dimethyl-4(1H)-pyridinone-3-olate) in the presence of various oxidants was studied. Hydrogen peroxide and monopersulfate were found to be the best oxidants when used with imidazole in acetonitrile at 4 °C, with up to 94% conversion. Dismutation of hydrogen peroxide was also observed when used as an oxidant. The epoxidation using hydrogen peroxide or monoperoxysulfate appears to be mild and very selective for strained alkenes. A mechanism is proposed where imidazole is required for activation of the oxidant and where a detected MnV = O species is proposed as the active species. Competitive reaction between H2O2 and the substrate for the active species is proposed and homolytic vs heterolytic scissions of the OO bond of the oxidant are discussed.
Silica microspheres containing high density surface hydroxyl groups as efficient epoxidation catalysts
Chandra, Prakash,Doke, Dhananjay S.,Umbarkar, Shubhangi B.,Vanka, Kumar,Biradar, Ankush V.
, p. 21125 - 21131 (2015/03/30)
Uniformly sized silica microspheres were synthesized by a hydrolysis-condensation method. The obtained material was etched with a mild aqueous potassium hydroxide solution for different periods of time to break their Si-O-Si bonds and increases the density of hydroxyl groups on their surfaces. The resulting materials were then used as transition metal-free catalysts for oxidation of olefins in the presence of hydrogen peroxide as a green oxidant. The materials were thoroughly characterized using various physicochemical techniques. These highly populated hydroxyl groups on the surface of silica microspheres were proven to be responsible for excellent conversion (up to 93%) and epoxide selectivity (up to 100%) for various olefins. Quantum mechanical calculations also corroborate the experimental findings. Furthermore, both experimental and theoretical studies show that tertiary silanols were present at the active sites of the catalyst surface and were responsible for olefin epoxidation.
METHOD FOR PRODUCING EPOXY COMPOUND AND CATALYST COMPOSITION FOR EPOXIDATION REACTION
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Paragraph 0214-0216, (2017/08/29)
PROBLEM TO BE SOLVED: To provide a method for producing an epoxy compound without needing a cumbersome purification process and the like where, in production of the epoxy compound, a content of heavy metals such as tungsten is extremely small, further preferably a content of a nitrogen-containing compound derived from an onium salt is small, and further more preferably a content of chlorine is small. SOLUTION: Provided is a method for producing an epoxy compound comprising epoxidizing a carbon-carbon double bond of a compound having a carbon-carbon double bond by reacting the same with hydrogen peroxide in the presence of at least either of a tungsten compound and a molybdenum compound, and an onium salt. The onium salt has four or more acyloxy groups of 1 to 4 carbon atoms and a total carbon number of the onium salt is 20 or more. COPYRIGHT: (C)2015,JPOandINPIT
