共查询到20条相似文献,搜索用时 156 毫秒
1.
Triethylammonium fluorochromate(VI), (C2H5)3NHCrO3F, TriEAFC and triethylammonium chlorochromate(VI), (C2H5)3NHCrO3Cl, TriEACC were prepared, supported on silica gel and used to quantitatively oxidize a number of organic substrates. These supported triethylammonium halochromates are versatile reagents ensuring effective oxidation of organic compounds, in particular of alcohols, under mild conditions. The durability, ease of work up and efficiency of TriEAFC and TriEACC are considerably increased upon their absorption on silica gel. 相似文献
2.
Shahriare Ghammamy Monir Rahnama Baghy Wong Wing-Tak Kheiroallah Mehrani Saied Maleki 《Transition Metal Chemistry》2007,32(2):257-261
The complex of propyltriphenylphosphonium bromochromate(VI), PrPh3P[CrO3Br] is easily synthesized in nearly quantitative yield using a direct reaction of chromium(VI) oxide and propyltriphenylphosphonium
bromide. This compound is a versatile reagent for the efficient and selective oxidation of organic substrates, in particular
for alcohols to their corresponding aldehydes or ketones, under mild conditions. This compound was characterized by IR, UV/Visible,
13C-n.m.r. and 1H-n.m.r. techniques. It crystallized in the monoclinic form and its crystal and molecular structure have been determined by
X-ray crystallography. 相似文献
3.
Shahriare Ghammamy Monir Rahnama Baghy Moniralsadat Mirrahimi Massimo Di Vaira Zahra Javanshir Kheiroallah Mehrani Saied Maleki 《Transition Metal Chemistry》2009,34(5):565-570
Benzyltriphenylphosphonium chlorochromate(VI), [(PhCH2)Ph3P][CrO3Cl], BTriPPCC, is easily synthesized in a nearly quantitative yield by direct reaction of Cr(VI) oxide and benzyltriphenylphosphonium
chloride. The complex was characterized by physico-chemical and spectroscopic methods. The use of phosphonium counter ion,
improves the quality of the BTriPPCC crystals. The compound was indeed crystallized and structurally characterized by X-ray
diffraction at 170(2) K. This compound is a versatile reagent for the efficient and selective oxidation of organic substrates,
in particular of alcohols to the corresponding aldehydes or ketones, in mild conditions. Due to the stability and solubility
of BTriPPCC, the reactions can be performed at room temperature and the separation of the products is easy. 相似文献
4.
《Journal of Coordination Chemistry》2012,65(20):3225-3236
Tetraethylammonium chlorochromate(VI), Et4N[CrO3Cl] is easily synthesized in nearly quantitative yield using a direct reaction of chromium(VI) oxide and tetraethylammonium chloride and characterized by elemental analysis, IR, UV/Visible, 1H-NMR and 13C-NMR techniques and single-crystal X-ray diffraction analysis (monoclinic system, space group C2(#5), with a = 12.023(3), b = 7.998(2), c = 14.527(4) Å, β = 114.187(4)°, V = 1274.4(6) Å3 and Z = 4). X-ray data determined the CH ··· O hydrogen bond that forms between the ethyl hydrogen of the cation and oxygen of the anion. This compound is a versatile reagent for efficient and selective oxidation of organic substrates, in particular for alcohols to their corresponding aldehydes or ketones, under mild conditions. 相似文献
5.
Ion-associated halochromates (halo=F, Cl, Br) from tetraphenylphosphonium cation (Ph4P+) are synthesized by stepwise solvent extraction technique and characterized based on XRD, spectral and thermal studies. The
Ph4P+CrO3Br- crystal is tetragonal with a=b=12.368 and c=7.511 ∮A. Thermal stabilities of these complexes are found to be decreasing in
the order of Ph4P+CrO3F-> Ph4P+CrO3Cl-> Ph4P+CrO3Br-.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
6.
Ali Reza MahjoubMohammad Zaman Kassaee 《Tetrahedron letters》2003,44(24):4555-4557
Tetramethylammonium fluorochromate(VI), (CH3)4N+CrO3F− (TMAFC), was prepared and used for quantitative oxidation of several organic substrates. This new compound is more efficient and has certain advantages over similar oxidizing agents in terms of the amount of oxidant and solvent required, short reaction times and high yields. 相似文献
7.
Jun-ichi Tamura Shigeo Koike Toshisada Shimadate 《Journal of carbohydrate chemistry》2013,32(4):531-535
Abstract The benzyl group is often used in organic synthesis, especially in carbohydrate chemistry, as one of the most useful of the hydroxyl protecting groups. Benzyl ethers are stable to basic conditions and the benzyl group is removed easily by hydrogenolysis or under Birch reduction conditions. Alternatively, the benzyl ether group is oxidized to benzoyl ester and removed under basic conditions. A few oxidation methods have been reported using more than a stoichiometric amount of chromium reagents such as CrO3-H2SO4 (Jones reagent)1 or CrO3-AcOH2. Here we report a new and mild oxidation of benzyl ether to benzoyl ester with a catalytic amount of RuO4 derived from RuCl3 and NaIO4. This method has proved effective in removing benzyl ether groups chemoselectively in the presence of benzylidene acetal and benzyl glycosidic functions. 相似文献
8.
Jacques Muzart A. N'ait Ajjou G. V. Nizova G. B. Shul'pin 《Russian Chemical Bulletin》1991,40(6):1294-1296
Cyclohexane, indane, and styrene was oxidized by H2O2 in the presence of CrO3 or (Bu3SnO)2CrO2 in a two-phase system or in an organic solvent with the formation of cyclohexanone, indanone, and benzaldehyde, respectively, as the major products. The oxidation of indane by the adduct of H2O2 with urea upon catalysis by CrO3 in acetone proceeds most efficiently.Université de Reims Champagne-Ardenne.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1454–1457, June, 1991. 相似文献
9.
Rational Syntheses of CdII and PbII Metal‐Organic Frameworks for Luminescence Sensing of Nitroaromatics,Ferric and Chromate Ions 下载免费PDF全文
Yu Wu Yulong Li Like Zou Jianshen Feng Jianqiang Liu Miaomiao Luo Jingwen Xu Reena Yadav Abhinav Kumar 《无机化学与普通化学杂志》2017,643(2):214-219
The metal‐organic frameworks (MOFs), {[Cd(L)(H2O)] · CH3OH · DMF} ( 1 ) and [Pb(L)(DMF)] ( 2 ) (L = 2,4‐dihydroxybenzaldehyde nicotinoylhydrazone), were synthesized and characterized using microanalyses, IR spectroscopy, and single‐crystal X‐ray diffraction. Single crystal X‐ray analyses revealed that both 1 and 2 exhibit 2D grid networks. The photoluminescence investigation indicates that 1 and 2 could be a prospective candidate for developing luminescencent sensors for the selective sensing of nitrobenzene, which is used as a precursor for explosives. The luminescent properties of 1 and 2 in different solvents were investigated and corroborated by theoretical calculations. Additionally compounds 1 and 2 also show selective sensing ability for Fe3+ as well as for CrO42– ions. 相似文献
10.
A. O. Okhlobystin I. V. Smolyaninov A. V. Okhlobystina N. T. Berberova Yu. Yu. Koldaeva V. F. Abdulaeva 《Russian Journal of Coordination Chemistry》2013,39(1):33-36
The chromium(III) tris-o-semiquinolate complex Cr(LSQ)3 (LSQ is 3,6-di-tert-butyl-o-semiquinone) and the monoanionic paramagnetic nickel(II) complex [n-Bu4N][Ni(L S SQ )(L S DT )] (L S SQ is o-thiosemiquinone, L S DT is benzene-1,2-dithiolate) are considered as electromediators of hydrogen sulfide oxidation in the presence of various organic substrates (hex-1-ene, oct-1-ene, benzene, toluene, and benzoic acid). It is revealed that the electrolysis of hydrogen sulfide at the oxidation potential of the mediators in the presence of the substrates affords the corresponding aliphatic and aromatic thiols in a yield of 62–75%. 相似文献
11.
Mihir K. Chaudhurp Shiv K. Chettri Gagan C. Mandal Pradip C. Paul Satya B. Paul Pendyala Srinivas 《Journal of Chemical Sciences》1995,107(4):305-316
An interpretative account of the results of reactions in aqueous medium of a highly peroxygenated vanadium(V) complex, K [V(O2
3]·3H2O, with different organic and inorganic substrates is presented. The reactions were monitored by solution EPR spectroscopy
and isolation of products at different stages of the reactions. Redox reactions between diperoxide, K[VO(O2)2(H2O)] and VOSO4 were conducted. The results of the investigation suggest that secondary oxygen exchange-reaction occurs which not only depends
on but also utilises the intermediates in the primary reaction during diperoxovanadate-dependent oxidation of VOSO4.
In an interesting reactiontris(acetylacetonato)-manganese(III), Mn(acac)3, on being reacted with a hydrogen peroxide adduct, KF·H2O2, and bpy and phen afforded crystalline [Mn(acac)2(bpy)] and [Mn(acac)2(phen)], respectively. The X-ray structural analysis of [Mn(acac)2(phen)] showed that the compound crystallised in orthorhombic space groupPbcn. The structure consists of a pseudooctahedral Mn(II) ion being bound to two acac−(C5H5O
2
−
) and a phen ligand with the molecule lying on two-fold axis.
Reactivity profiles of two new chromium(VI) reagents viz., pyridinium fluorochromate, C5H5NH[CrO3F] (PFC), and quinolinium fluorochromate C9H7NH [CrO3F] (QFC), have been presented. The compounds are capable of acting as both electron-transfer and oxygen-atom-transfer agents.
The X-ray analysis of PFC crystals reveals that the compound crystallises in the orthorhombic space group CmcZ1. The structure consists of discrete pyridinium cations and CrO3 F anions with no significant hydrogen bonding. This results in total disorder of the pyridinium cation. The tetrahedral [CrO3 F]− ion lies on a crystallographic mirror plane. 相似文献
12.
Molecular‐Level Understanding of the Photocatalytic Activity Difference between Anatase and Rutile Nanoparticles 下载免费PDF全文
Dr. Wooyul Kim Prof. Takashi Tachikawa Gun‐hee Moon Prof. Tetsuro Majima Prof. Wonyong Choi 《Angewandte Chemie (International ed. in English)》2014,53(51):14036-14041
The generation of oxidants on illuminated photocatalysts and their participation in subsequent reactions are the main basis of the widely investigated photocatalytic processes for environmental remediation and selective oxidation. Here, the generation and the subsequent diffusion of .OH from the illuminated TiO2 surface to the solution bulk were directly observed using a single‐molecule detection method and this molecular phenomenon could explain the different macroscopic behavior of anatase and rutile in photocatalysis. The mobile .OH is generated on anatase but not on rutile. Therefore, the photocatalytic oxidation on rutile is limited to adsorbed substrates whereas that on anatase is more facile and versatile owing to the presence of mobile .OH. The ability of anatase to generate mobile .OH is proposed as a previously unrecognized key factor that explains the common observations that anatase has higher activity than rutile for many photooxidative reactions. 相似文献
13.
This paper describes the oxidation of benzylic and allylic alcohols under non-aqueous and aprotic conditions or microwave conditions using benzyltriphenylphosphonium chlorochromate (1) PhCH2PPh3CrO3.HCl which has been prepared by mixing an aqueous solution of benzyltriphenylphosphonium chloride with CrO3 in 6 N HCl at room temperature. This reagent is stable orange powder which may be stored for months without loss of its activity. This compound is readily soluble in organic solvents such as acetonitrile, chloroform and dichloromethane and slightly soluble in carbon tetrachloride, ether and hexane. the oxidation under microwave conditions is much more faster. 相似文献
14.
This work is focused on the role of gold and Al3CrO6 support for physicochemical properties, and catalytic activity of supported nickel catalysts in partial oxidation of methane
(POM). Catalysts, containing 5% Ni and 5% Ni-2% Au active phases dispersed on mono- (Al2O3, Cr2O3) and bi-oxide Al3CrO6 support, were investigated by TPR, BET and XRD methods, and the activity tests in POM reaction were carried out. Bimetallic
Ni-Au catalysts dispersed on Al3CrO6 support remained highly stable and active. The amorphous binary oxide Al3CrO6 can stabilize considerable amount of Cr4+, Cr5+, and Cr6+ species in Ni-Au/Al3CrO6 catalyst network during its calcination in the air. Nickel supported on binary oxide Ni/Al3CrO6 can form Ni(III)CrO3 bi-oxide phase in reductive conditions. During TPR H2 reduction of Ni-Au/Al3CrO6 catalyst chromium(II) oxide Cr(II)O phase is observed. After POM reaction the existence of bimetallic Au-Ni alloy was experimentally
confirmed on mono-oxide Al2O3 support surface, but its formation was not identified on bioxide Al3CrO6 support.
Published in Russian in Kinetika i Kataliz, 2009, Vol. 50, No. 1, pp. 149–156.
The article is published in the original.
Based on a report at the VII Russ. Conf. on Mechanisms of Catalytic Reactions (with international participation), St. Petersburg,
July 2–8, 2006. 相似文献
15.
A charge-transfer compound [(CH3)3CNH3]3[PMo12O40] · 2H2O was synthesized and characterized by IR, UV, ESR, diffusion reflectance electronic spectrum, cyclic voltammogram and X-ray
crystallography. Oxygen atoms of the polyoxometalate anion, N atoms of organic substrates (CH3)3CNH2 and O atoms of water molecules are involved in hydrogen bonding. The solid reflectance electronic spectra and IR data indicate
the presence of interaction between the [PMo12O40]3− and the organic substrates in the solid state. Photosensitivity to ultraviolet light was assessed for the compound, showing
that charge-transfer resulted from oxidation of the organic substrates and the reduction of the heteropolyanion. 相似文献
16.
J. M. Lo C. L. Tseng S. J. Yeh 《Journal of Radioanalytical and Nuclear Chemistry》1988,123(2):683-693
We have recently developed a new method of measuring the initial51Cr(III) produced from nuclear recoil of K2CrO4. In our method, K2CrO4 was mixed with MgO in the presence of a small amount of water, and the mixture was irradiated in a nuclear reactor. After irradiation, the mixture was dissolved in water, and MgO precipitate was separated from the solution. The yield of recoil51Cr(III) could be calculated from the51Cr activity in the precipitate measured. On the other hand, the yield of retention of51Cr as chromate could be calcualted from the activity found in the supernatant. The51Cr(III) yield thus obtained is almost a factor of 2 higher than observed in pure K2CrO4 without mixing with MgO, irradiated under the same condition. Another important observation is that the51Cr(III) yield is independent of irradiation time in the presence of MgO. Without MgO, the observed51Cr(III) yield decreases with increasing irradiation time, suggesting possible oxidation of Cr(III) to chromate during irradiation. This variation is not observed in the system of K2CrO4 containing MgO, indicating that the initial Cr(III) is adsorbed immediately after nuclear recoil by MgO and is protected from oxidation by gamma radiation. 相似文献
17.
Andrei V. Bekish 《Tetrahedron letters》2012,53(24):3082-3085
α-Carbon–carbon bond cleavage is shown to be a general side reaction accompanying the oxidation of unbranched primary alcohols to the corresponding carboxylic acids using HNO3, CrO3/H2SO4/H2O/acetone, CrO3/CH3COOH, PDC/DMF, H5IO6/CrO3, KMnO4/H+, KMnO4/HO?, NiCl2/NaClO, TEMPO/PhI(OAc)2. Therefore, the product formed is always contaminated with a carboxylic acid containing one carbon atom less. Systems such as PhI(OAc)2/TEMPO or H5IO6/CrO3/CH3CN reduce to a minimum the content of this impurity. Temperature, the order of reagent addition, and additives such as oxalic acid or cerium salts produce a profound effect on the formation of the undesirable impurity during the Jones oxidation of primary alcohols. 相似文献
18.
J. de Pascual Teresa J.G. Urones A.Montaña Pedrero P.Basabe Barcala 《Tetrahedron letters》1985,26(46):5717-5720
Oxidative cyclization of Labdanediol (XII) and methyl Labdanolate (Ib) with Pb(OAc)4, and subsequent oxidation with reagents as RuO4, O3, CrO3, or (But)2 CrO4 affords, in excellent yield, the natural diterpenic lactones II, III, VII, VIII, XI and XIII, isolated from 相似文献
19.
Dalma Gyepesov Vratislav Langer 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(2):111-113
The structure analysis of so‐called 9CaO·4CrO3·Cr2O3 proved it to be the title compound, decacalcium hexakis[chromate(V)] chromate(VI), with the simultaneous presence of unusual chromium oxidation states. The structure determination was carried out on a crystal that had inversion twinning. The CrVIO4 tetrahedron is situated on a threefold axis and is disordered over two possible orientations that share three O atoms, while the CrVO4 tetrahedra are in general positions and are ordered. The charge is balanced by Ca2+ cations, one of which is located on a threefold axis. The Ca2+ ions are coordinated by six, seven or eight O atoms. The compound is a significant phase in the CaO–CrOx system and its formation reduces the refractoriness of calcium‐rich compositions in an oxidizing atmosphere. 相似文献
20.
Ahmad R. Bekhradnia Forohe Zahir Sattar Arshadi 《Monatshefte für Chemie / Chemical Monthly》2008,35(3):521-523
Efficient selective oxidation of primary, secondary, and benzylic alcohols to the corresponding carbonyl compounds by a new
chromium oxidizing reagent, pyridinium-1-sulfonate fluorochromate, C5H5NSO3H [CrO3F] (PSFC) is reported. Various cholesterol derivatives were easily converted to related oxocholesterol from allylic oxidation at lower
temperature in comparison to other general oxidants. This oxidation procedure is simple and affords good yields. 相似文献