Dinuclear copper complexes with cyanamide derivatives as bridging ligands
摘要:
Three mixed-valence copper complexes [{Cu(phen)(2)}(2)(mu-L)](PF6)(2) (where phen = 1, 10-phenanthroline, L = 1,4-dicyanamidobenzene (dicyd)), 1,4-dicyanamido-2,5-dimethylbenzene (Me(2)dicyd) and 1,4-dicyanamido-2,5-dichlorobenzene (Cl(2)dicyd), and one dinuclear Cu(II) complex [{Cu(phen)(2)}(2)(mu-apc)](PF6)(3) (where ape = monoanion of 4-azo(phenyleyanamido)benzene) have been prepared and characterized by elemental analysis, IR and electronic absorption spectroscopies and cyclic voltammetry. [{Cu(phen)(2)}(2)(mu-apc)](PF6)(3) center dot 2CH(3)COCH(3) crystallized in the triclinic system and both five-coordinate Cu(II) ions in the dinuclear unit are linked through a bridging 4-azo(phenylcyanamido)benzene (apc) ligand. The cyanamide group (NCN) of the bridging ligand is coordinated to Cu(II) ions through the cyano-nitrogen and amido-nitrogen. The bond length between Cu(1) and cyano-nitrogen is slightly larger than that formed by Cu(2) and amido-nitrogen. The angular structural index parameters, tau, for Cu(1) and Cu(2) are 0.9 and 0.5, respectively. The copper(II) atoms display a different geometry with a N-5 chromophore group. The intra Cu...Cu separation is 5.156(1) angstrom. All of the dicyd dinuclear copper complexes show radical anion absorption. (C) 2008 Elsevier Ltd. All rights reserved.
Crystal structures, electronic properties and structural pathways of four [Cu(phen)2Cl][Y] complexes (phen = 1,10-phenanthroline; Y = BF4−·0.5H2 O, PF6−, CF3SO3−·H2O or BPh4−)
摘要:
[Cu(phen)₂Cl][BF₄]·0.5H₂O(phen = 1,10-菲啰啉)、[Cu(phen)₂Cl][PF₆]、[Cu(phen)₂Cl][CF₃SO₃]·H₂O和[Cu(phen)₂Cl][BPh₄]的晶体结构已通过X射线晶体学确定。三个配合物1-3包含一个CuN₄Cl色团,具有基于正方形的金字塔失真三方双锥立体化学,而4则涉及一个三方双锥失真基于正方形的金字塔立体化学。通过散点图分析比较了1-4中CuN₄Cl色团的几何形状与已知结构的四个[Cu(phen)₂Cl][Y]配合物的几何形状。这八个阳离子失真异构体的散点图表明,所有配合物都涉及CuN₄Cl色团的 -A + B途径失真,其中-A(约60%)和+B(约40%)。线性和并行关联的观察可以替代性地解释为对CuN₄Cl色团的对称模式ν_sym和非对称模式ν_asym振动混合的振动耦合的直接观察。这强调了在一系列阳离子失真异构体中确定多个配合物结构的必要性,其中配体的立体化学范围的极限由电子反射光谱的测量指示。
Copper complexes with 1,10-phenanthrolines as efficient catalysts for oxidation of alkanes by hydrogen peroxide
摘要:
The Copper complexes with 1,10-phenanthrolines and 1,10- phenanthrolines-5,6-diones were synthesized and characterized by elemental analysis and spectra. One complex was characterized by X-ray analysis. The complexes turned out to be active in oxidations of cyclic, branched and linear alkanes. Hydrogen peroxide (50%) was used as an oxidant. The reactions were carried out in solvent acetonitrile at relatively the low temperatures (40-60 degrees C). Alkyl hydroperoxides are the primary products which partly decompose in the course of the reaction to produce mainly ketones (aldehydes) and alcohols. Treating the reaction mixture with PPh3 leads to the transformation of alkyl hydroperoxides (ROOH) to corresponding alcohols (ROH).