- Electronic and vibrational structure of copper dibromide
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Absorption and laser-induced fluorescence spectra of copper dibromide in a solid neon matrix are reported. Similar to those for copper dichloride, electronic transitions between the low-lying so-called ligand field states states are forbidden by the u?g rule, appear as a result of vibronic Herzberg-Teller coupling. The observed transition energies are in good agreement with the adiabatic state energies derived from a recent gas-phase photodetachment study by Wang and co-workers. The matrix study with its much higher resolution yields detailed information about the copper halide electronic states and their vibrational structures.
- Lorenz, Martin,Bondybey, Vladimir E.
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- Coordination driven or/and H-bonded Cu(II)-N,N-dialkylisonicotinamide frameworks
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Reactions of N,N-diisopropylisonicotinamide (L) with anhydrous CuCl 2, CuBr2 and Cu(ClO4)2· 6H2O yielded: (a) an ionic product with the molecular composition of [CuL2(H2O)4]·2[CuLCl3] 1; (b) a coordination polymer [CuL2Br2]n 2 and (c) a mononuclear complex [CuL4(C3H8O) 2]·(ClO4)2] 3, respectively. Similarly, the reaction of N,N-diisobutylisonicotinamide (L′) with Cu(NO 3)2·3H2O yielded a coordination polymer [{CuL′2(H2O)2}(NO3) 2]n 4. The ligands L and L′ coordinate in a monodentate fashion through the pyridine nitrogen atom to the metal centers in complexes 1 and 3. However, complexes 2 and 4 are coordination polymers in which the corresponding ligands (L and L′) act as bridging bidentate between metal centers to form 1D double chains. All the four complexes form networks through coordination polymerization and/or hydrogen bonding.
- Pannu, Ajay Pal Singh,Kapoor, Pratibha,Hundal, Geeta,Kapoor, Ramesh,Martinez-Ripoll, Martin,Butcher, Rayond J.,Hundal, Maninder Singh
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- Structural and chromotropism properties of copper(II) complexes containing a tridentate ligand
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Abstract: Two dinuclear complexes of [LCu(Cl)(μ-Cl)CuCl3][LCu(Cl)(μ-Cl)CuL(H2O)]Cl, 1 and [LCu(Br)(μ-Br)]2Br, 2, with a tridentate ligand of 3-((pyridin-2-ylmethyl)amino)propanamide, L, were prepared and characterized by physicochemical (elemental analyses, molar conductance measurements, thermogravimetry) and spectroscopic (IR, UV–vis) data. The crystal structures of compounds have been identified by single-crystal X-ray diffraction analyses and showed that the tridentate ligand L functions as an N2O-donor via the nitrogen atoms of the secondary amine and pyridyl moieties together with the oxygen atom of the amide group. The structural geometry about the copper(II) ions is a distorted square pyramid. The compounds are chromotropic and their reversible chromotropism was investigated by utilizing spectral analysis. The halochromism was due to structural change and followed by ionization of the coordinated water molecules and deprotonation of the secondary amine moiety. It was discovered that the solvatochromism of the compounds arisen from the structural change followed by the solvation of the vacant sites of the complexes. The compounds demonstrated ionochromism and sensitivity and selectivity towards CN? and N3? anions in the presence of other pseudo-halide anions. Graphic abstract: [Figure not available: see fulltext.].
- Motalebi, Motahareh,Golchoubian, Hamid,Rezaee, Ehsan
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- Copper (II) halide complexes with NNO tridentate ligand as chromotropic probes; synthesis, structural characterization and spectroscopic properties
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This study reports chromotropism of two newly synthesized copper(II) complexes of formula [CuLCl2] and [CuLBr2]?MeOH where L = N-(2-pyridylmethyl)-1-hydroxypropylamine. The structure of the complexes was investigated by infrared spectroscopy, electronic absorption spectroscopy, elemental analysis, molar conductance measurements, and thermal analysis. Single Crystal X-ray structure determination reveals both complexes to adopt a distorted square-pyramidal geometry. Their chromotropic properties were investigated using electronic absorption spectroscopy. The complexes are solvatochromic in solvents with different polarities. The aqueous solutions of the complexes exhibit a variety of colors in the pH range of 1.8 to 11.4 showing that the compounds are halochromic. The complexes are also thermochromic and show reversible color changes in different temperatures in dimethyl sulfoxide solutions. The solution study reveals that the observed chromotropism originates from structural changes of the complexes in different conditions.
- Bouwman, Elisabeth,Golchoubian, Hamid,Shirvan, Atie,Siegler, Maxime A.
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- X-ray Absorption and Electron Paramagnetic Resonance Guided Discovery of the Cu-Catalyzed Synthesis of Multiaryl-Substituted Furans from Aryl Styrene and Ketones Using DMSO as the Oxidant
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The first example of DMSO serving not only as a solvent but also as an oxidant to promote the oxidation of Cu(I) to Cu(II) has been demonstrated. X-ray absorption and electron paramagnetic resonance evidence revealed a single-electron redox process where DMSO could oxidize Cu(I) to Cu(II). The novel discovery guided the rational design of copper-catalyzed oxidative cyclization of aryl ketones with styrenes to furans, providing a new method for the synthesis of multiaryl-substituted furans from cheap and readily available starting materials.
- Wu, Yong,Huang, Zhiyuan,Luo, Yi,Liu, Dong,Deng, Yi,Yi, Hong,Lee, Jyh-Fu,Pao, Chih-Wen,Chen, Jeng-Lung,Lei, Aiwen
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supporting information
p. 2330 - 2333
(2017/05/12)
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- Aqueous copper-mediated living polymerization: Exploiting rapid disproportionation of CuBr with Me6TREN
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A new approach to perform single-electron transfer living radical polymerization (SET-LRP) in water is described. The key step in this process is to allow full disproportionation of CuBr/Me6TREN (TREN = tris(dimethylamino)ethyl amine to Cu(0) powder and CuBr2 in water prior to addition of both monomer and initiator. This provides an extremely powerful tool for the synthesis of functional water-soluble polymers with controlled chain length and narrow molecular weight distributions (polydispersity index approximately 1.10), including poly(N-isopropylacrylamide) , N,N-dimethylacrylamide, poly(ethylene glycol) acrylate, 2-hydroxyethyl acrylate (HEA), and an acrylamido glyco monomer. The polymerizations are performed at or below ambient temperature with quantitative conversions attained in minutes. Polymers have high chain end fidelity capable of undergoing chain extensions to full conversion or multiblock copolymerization via iterative monomer addition after full conversion. Activator generated by electron transfer atom transfer radical polymerization of N-isopropylacrylamide in water was also conducted as a comparison with the SET-LRP system. This shows that the addition sequence of l-ascorbic acid is crucial in determining the onset of disproportionation, or otherwise. Finally, this robust technique was applied to polymerizations under biologically relevant conditions (PBS buffer) and a complex ethanol/water mixture (tequila).
- Zhang, Qiang,Wilson, Paul,Li, Zaidong,McHale, Ronan,Godfrey, Jamie,Anastasaki, Athina,Waldron, Christopher,Haddleton, David M.
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supporting information
p. 7355 - 7363
(2013/07/11)
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- Microwave-assisted carbohydrohalogenation of first-row transition-metal oxides (M = V, Cr, Mn, Fe, Co, Ni, Cu) with the formation of element halides
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The anhydrous forms of first-row transition-metal chlorides and bromides ranging from vanadium to copper were synthesized in a one-step reaction using the relatively inexpensive element oxides, carbon sources, and halogen halides as starting materials. The reactions were carried out in a microwave oven to give quantitative yields within short reaction times.
- Berger, Matthias,Neumeyer, Felix,Auner, Norbert
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supporting information
p. 11691 - 11693
(2013/11/19)
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- Ultrafast synthesis of ultrahigh molar mass polymers by metal-catalyzed living radical polymerization of acrylates, methacrylates, and vinyl chloride mediated by SET at 25 °C
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Conventional metal-catalyzed organic radical reactions and living radical polymerizations (LRP) performed in nonpolar solvents, including atom-transfer radical polymerization (ATRP), proceed by an inner-sphere electron-transfer mechanism. One catalytic system frequently used in these polymerizations is based on Cu(I)X species and N-containing ligands. Here, it is reported that polar solvents such as H2O, alcohols, dipolar aprotic solvents, ethylene and propylene carbonate, and ionic liquids instantaneously disproportionate Cu(I)X into Cu(0) and Cu(II)X2 species in the presence of a diversity of N-containing ligands. This disproportionation facilitates an ultrafast LRP in which the free radicals are generated by the nascent and extremely reactive Cu(0) atomic species, while their deactivation is mediated by the nascent Cu(II)X2 species. Both steps proceed by a low activation energy outer-sphere single-electron-transfer (SET) mechanism. The resulting SET-LRP process is activated by a catalytic amount of the electron-donor Cu(0), Cu2Se, Cu2Te, Cu2S, or Cu2O species, not by Cu(I)X. This process provides, at room temperature and below, an ultrafast synthesis of ultrahigh molecular weight polymers from functional monomers containing electron-withdrawing groups such as acrylates, methacrylates, and vinyl chloride, initiated with alkyl halides, sulfonyl halides, and N-halides.
- Percec, Virgil,Guliashvili, Tamaz,Ladislaw, Janine S.,Wistrand, Anna,Stjerndahl, Anna,Sienkowska, Monika J.,Monteiro, Michael J.,Sahoo, Sangrama
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p. 14156 - 14165
(2008/02/10)
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- Thermal, vibrational and EPR studies of Cu(II) bromide bis(p-methylaniline) and bis(m-methylaniline) complexes.
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[CuBr(2)(pMA)(2)] and [CuBr(2)(mMA)(2)] complexes (pMA: p-methylaniline, mMA: m-methylaniline) have been prepared and characterized by elemental analyses, thermogravimetric analyses, magnetic moment measurements, and IR, Raman and EPR spectroscopic studies. Coordination effects on the vibrational spectra of the ligands have been investigated. The room temperature EPR spectra of the complexes and their simulated spectra are also discussed in detail. The vibrational and EPR spectral studies suggest that the coordination sphere around Cu(II) consist of a distorted tetragonal structure.
- Golcuk,Altun,Guner,Kumru,Aktas
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p. 303 - 309
(2007/10/03)
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- Pyridine-type complexes of transition-metal halides XIV. Part III. Complexes with 2,4-, 2,6-, 3,4- and 3,5-lutidines
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Compounds obtained by a solid-gas phase reactions between copper(II) chloride and bromide and 2,4-, 2,6-, 3,4- and 3,5-lutidines were studied using thermogravimetry, far-infrared, electronic spectroscopy and X-ray diffraction. The results were compared with the corresponding data for the similar compounds with methylpyridines and 2,4,6-collidine. A special attention was paid to the host-guest phenomenon, a new structural feature of transition-metal halide complexes.
- Meszaros Szecsenyi,Wadsten,Carson,Bencze,Liptay
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- Pyridine-type complexes of transition-metal halides XIII: Solid state studies of copper(II) chloride and bromide complexes with methylpyridines - Part II: Complexes with 2- and 4-methylpyridine and 2,4,6-collidine
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This study is concerned with the reactions between copper(II) chloride and bromide with 2- and 4-methylpyridine and 2,4,6-collidine. The effects of the methyl groups(s)' position in a series of methylpyridines on the host-guest phenomenon in the formed copper(II) halide compounds were studied using thermogravimetry, far-infrared and electronic spectroscopy and X-ray diffraction. Copper(II) halide complexes with 4-methylpyridine and the copper(II) chlorido complex with 2,4,6-collidine exhibit zeolite properties. The reaction of copper(II) halides with 2-methylpyridine resulted in complex formation but no host-guest phenomenon was detected in these complexes. No complex formation was observed between 2,4,6-collidine and copper(II) bromide.
- Szécsényi, K. Mészáros,Wadsten,Carson,Bencze, é.,Kenessey,Liptay
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p. 255 - 261
(2008/10/09)
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- Pyridine-type complexes of transition-metal halides XII. Solid-state studies of copper(II)-chloride and bromide complexes with methylpyridines. Part I: Complexes with 3-methylpyridine
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The structural characteristics and thermal behaviour of the copper(II)-chloride and bromide complexes of 3-methylpyridine synthesised by a solid-gas phase technique are described. Far-IR spectra and results of the X-ray studies of the parent compounds and the intermediates indicate a host-guest phenomenon, a new structural feature of transition-metal halide complexes.
- Szecsenyi, K. Meszaros,Wadsten, T.,Carson, B.,Bencze, E.,Kenessey, G.,et al.
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- Synthesis and Transformations of the Copper(II) N-(2-Aminoethyl)aziridine and N-(2-Haloethyl)ethylenediamine Complexes
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The copper(II) complexes with N-(2-aminoethyl)aziridine (L') and N-(2-haloethyl)ethylenediamine (L'') with the molecular compositions [CuLX2] and [CuL2X2], where L is L' or L'', X is Cl or Br, were synthesized. According to the IR spectra, the compounds [CuLX2] are coordination polymers consisting of tetrahedrally distorted hexacoordinated species. The complex [CuL''Br2] disproportionates in water to form [CuL''2Br2]. Refluxing of [CuL''X2] and [CuL''2X2] in n-butanol results in intraspheric transformation of their L'' ligands into piperazine. Reaction of all the obtained copper(II) derivatives with formaldehyde initiates formation of the piperazine ring.
- Ukraintsev,Esikov,Krasnov,Potekhin
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p. 1832 - 1834
(2007/10/03)
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- Synthesis of some 3d-Metal Complexes of 2,6-Diacetylpyridine(benzyl and acetone)hydrazone
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2,6-Diacetylpyridine bis(benzyl and acetone)hydrazone and some 3d-metal complexes have been prepared. These complexes are five-coordinated trigonal bipyramidal. The ligand coordinates through the pyridine-N and amide-N. Formation of two chelate rings by one molecule of ligand, is a feature that undoubtedly enhances the stability of the complexes.
- Singh,Ansari,Rana
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p. 448 - 451
(2007/10/03)
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- 1-phenyl-6-one-pyrimidine derivatives
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A compound of formula (I): STR1 wherein R1 and R2 are independently selected from hydrogen, halogen, haloalkyl, alkoxy or nitro, provided that R1 and R2 are not both nitro; R3 and R4 are independently selected from hydrogen, halogen, alkyl or cycloalkyl; R5 is halogen, nitro, haloalkyl, haloalkoxy or --S(O)n R10 ; R6 is halogen, nitro, haloalkyl, haloalkoxy or --S(O)n R10 ; R7 is hydrogen, halogen, hydroxyalkyl, cyano, nitro, alkoxy, --S(O)n R10, NR11 R12, haloalkyl or formyl; R8 is hydrogen, halogen, NR11 R12, alkyl, cycloalkyl or S(O)n R10 ; and R9 is oxygen or sulphur; where n is 0, 1 or 2; and R10 is alkyl, haloalkyl or cycloalkyl; and R11 and R12 are independently selected from hydrogen, alkyl or cycloalkyl or R11 and R12 together with the nitrogen to which they are attached form a heterocyclic group; provided that when R5 is trifluoromethyl at least one of the following applies: (i) R1 or R2 is haloalkyl or alkoxy; (ii) R3 or R4 are alkyl or cycloalkyl; (iii) R6 is haloalkoxy, nitro or --S(O)n R10 ; (iv) R7 is nitro, hydroxyakyl, alkoxy, S(O)n R10, NR11 R12, formyl or haloalkyl; (v) R8 is other than hydrogen; (vi) R9 is sulphur; and further provided that (a) R1, R2, R3 and R4 are not all fluorine and (b) when R5 is chlorine, R1 and R2 are both halogen.
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- Process for making and for polymerizing chromenes and products thereof
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This invention relates to a solvent process for the conversion of aromatic propargyl ethers into chromenes. The process can be catalyzed with copper or zinc salts. The preferred salt is cuprous chloride. The most preferred solvent is dichlorobenzene. The invention also relates to chromene products formed using the process and to the polymerization of that chromene product and its polymerized product, the latter product having substantially improved flexural modulus and flexural strength properties. The polymerized product is also moisture insensitive.
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- Detailed spectrophotometric study of copper(II) halides in anhydrous methanol
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A spectrophotometric study of the copper(II) chlorides and the copper(II) bromides in anhydrous methanol was carried out at 25°C and at constant ionic strength (1 mol·L-1). A matrix rank treatment of the experimental data followed by the testing of different theoretical models confirmed the presence of four mononuclear complexes for both systems, viz. CuX+, CuX2, CuX3-, and CuX42-. Overall stability constants calculated for the chlorocuprates are β1 = 2.8 × 102, β2 = 1.6 × 104, β3 = 2.3 × 105, and β4 = 4.5 × 105 and for the bromocuprates are β1 = 5.2 × 103, β2 = 3.9 × 105, β3 = 2.0 × 106, and β4 = 2.1 × 106. Individual electronic spectra of all species in methanol are reported for the first time. In this solvent the tetracoordinated chloro complex exhibits a calculated absorption maximum in the near-IR region consistent with a square-planar structure, in contrast to the structure in the solid state, while for the tetrabromocuprate the structure of a flattened tetrahedron is confirmed.
- Khan,Meullemeestre,Schwing,Vierling
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p. 3306 - 3309
(2008/10/08)
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- STUDIES ON TRANSITION-METAL PICOLINE COMPLEXES - I. PREPARATION AND THERMOANALYTICAL INVESTIGATIONS.
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A large number of transition-metal picoline halides were prepared, and their thermal decompositions were investigated by TG, DTG, DTA and thermomicroscopy. The compounds were classified on the basis of their thermal properties and two possible mechanisms of thermal decomposition were established.
- Liptay,Borbely-Kuszmann,Nagy
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- Oxidation process for alkylaromatics
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A process is provided for oxygenating alkyl-substituted aromatic compounds. Alkyl-substituted aromatic compounds in the liquid phase are contacted with molecular oxygen at a temperature below 200° C. in the presence of a catalyst system which is substantially insoluble in the reaction mixture at reaction conditions. The catalyst components are a suspended copper compound and a suspended bromine compound which preferably are associated with a major quantity of a suitable catalyst support material. Optionally, the reaction can be carried out in the presence of minor amounts of acetic acid, acetic anhydride or suitable inorganic nitrate compounds.
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