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91.
Copper(II) complexes were prepared with the new N(2)S(thioether) ligand 2-methylthio-N-(2-pyridylmethyl)acetamide (2-HL(N2S)). [Cu(2-L(N2S))Cl(MeOH)], which formed in the presence of excess triethylamine, is a distorted square pyramidal complex containing the ligand with the amide nitrogen deprotonated. The structurally analogous complex, [Cu(2-HL(N2S))Cl(2)], which formed in the absence of triethylamine, contains 2-HL(N2S) in the tautomeric imidic acid form. Neutral copper(II) N(2)S(thioether)S(thiolate) species were generated by addition of alkyl or aromatic thiolates to [Cu(2-L(N2S))Cl(MeOH)] and an unusual decomposition pathway was discovered. 相似文献
92.
The preparation and isolation in the solid state of five aryl 1,2,3,5-dithia- and diselenadiazolyls is reported. The structure of the dimer of 4-Cl? C6H4? CN2S2 in the solid state was obtained: monoclinic, C2/c with Z = 8, a = 20.982(10), b = 10.058(3), c = 15.867(6) Å, β = 93.34(4)°, R = 0.066, Rw = 0.053 for 1 099 data. Cyclic voltammetry shows reversible oxidation to a 6π cation for all 10 compounds in both CH2Cl2 and CH3CN; reversible reduction to an 8π anion is observed in CH2Cl2 for all except X = CF3, E = S. The reductions are only quasi-reversible in CH3CN for E = Se. The oxidation process is independent of chalcogen type; the reduction process is found to be about 0.2 V more negative for E = S vs E = Se. 相似文献
93.
Bhargava S Hou J Parvez M Sorensen TS 《Journal of the American Chemical Society》2005,127(11):3704-3705
The first X-ray crystal structures of two different bicyclo[1.1.0]butanones show a very long transannular bond of 1.69 A and a large carbonyl pyramidal distortion of 0.26 A out of the plane of the three carbons. These features are those expected of molecules with a hybrid cyclopropanone-oxyallyl structure, and these structures differ markedly from those of the parent bicyclo[1.1.0]butane skeleton. 相似文献
94.
Howard C. Clark George Ferguson Vimal K. Jain Masood Parvez 《Journal of organometallic chemistry》1984,270(3):365-373
Compounds of the types Me3PtX(NN) (where X = Cl, I, OAc, NO3; NN = bis(1-pyrazolyl)methane (pz2CH2), bis(3,5-dimethyl-1-pyrazolyl)methane ((Me2pz)2CH2), or bis(2-pyridyl)methane (py2CH2)), [Me3Pt(NNN)][PF6] (where NNN=tris(1-pyrazolyl)methane (pz3CH), or tris(2-pyridyl)methane (py3CH)), and [Me3Pt((Me2pz)2CH2(py)][PF6] have been prepared and characterized by elemental analyses and 1H and 13C NMR spectroscopy; the structure of Me6PtI[(Me2pz)2CH2] (1) has also been determined by X-ray crystallography. Crystals of 1 are orthorhombic, space group Pcmn with four molecules in a unit cell of dimensions a 11.936(5), b 14.462(4), c 10.138(5) Å. The structure was solved by the heavy-atom method and refined by full-matrix least-squares calculations to R = 0.022 for 1719 observed data. The molecule has crystallographic mirror symmetry. The Pt atom has octahedral geometry with one methyl group trans to iodine and two methyl groups trans to the N atoms of the bidentate ligand (Pt---I 2.843(1), Pt---N, 2.236(4), Pt---C 2.077(6) (trans to I) and 2.032(5) Å (trans to N)). 相似文献
95.
The self-assembly of supramolecular copper "tennis balls" that possess unusual magnetic properties using a small pyridyl amide ligand is described. Copper(II) complexes of N-(2-pyridylmethyl)acetamide (HL) were synthesized in methanol. In the absence of base, the mononuclear complex [Cu(HL)(2)](ClO(4))(2) (1) was prepared. The structure of 1, determined by X-ray crystallography, contains a copper(II) ion surrounded by bidentate HL ligands coordinated via the pyridyl N atom and the carbonyl O atom in a trans, square planar arrangement. Reactions carried out in the presence of triethylamine resulted in cluster complexes [Cu(8)L(8)(OH)(4)](ClO(4))(4) and [Cu(8)L(8)(OH)(4)](CF(3)SO(3))(4) [2(ClO(4))(4) and 2(OTf)(4), respectively]. The cationic portions of 2(ClO(4))(4) and 2(OTf)(4) are isostructural, containing eight copper(II) ions, eight deprotonated ligands (L(-)), and four mu(3)-hydroxide ligands. The top and bottom halves of the cluster are related by a pseudo-S(4) symmetry operation and are held together by bridging L(-) ligands. Solutions of 2(ClO(4))(4) and 2(OTf)(4), which were shown to contain the full [Cu(8)L(8)(OH)(4)](4+) fragment by electrospray mass spectrometry and conductance experiments, are EPR silent. Magnetic susceptibility measurements for 2(ClO(4))(4) as a function of temperature and magnetic field showed the Cu ions all to exhibit magnetic moments in the range expected for the d(9) configuration. At low temperatures, the magnetization was reduced due to predominantly antiferromagnetic interactions between ions. Analysis showed that partially frustrated interactions among the four Cu ions making up each half of the cluster gave good agreement with the data once a large molecular anisotropy was taken into account, with J(c) = 106 cm(-1), D = 27 cm(-1), and g = 2.17. 相似文献
96.
Karm Hans Masood Parvez Sumera Mahboob Imtiaz‐ud‐Din Muhammad Mazhar Saqib Ali 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(11):m559-m562
The central Ge atoms in the structures of 3‐(2‐fluorophenyl)‐3‐(triphenylgermyl)propionic acid, [Ge(C6H5)3(C9H8FO2)], 3‐(2‐tolyl)‐3‐(tri‐4‐tolylgermyl)propionic acid, [Ge(C7H7)3(C10H11O2)], and 3‐(4‐tolyl)‐3‐(tribenzylgermyl)propionic acid, [Ge(C7H7)3(C10H11O2)], are four‐coordinate with slightly distorted tetrahedral geometry. The Ge—Csp3 distances [1.970 (3)–1.997 (3) Å] are significantly longer than the Ge—Caromatic distances [1.940 (3)–1.959 (2) Å]. In all three structures, the molecules form dimeric pairs about inversion centres through strong hydrogen‐bonding interactions between carboxylic acid groups. 相似文献
97.
The conjugate additions of (2-piperidyl)acetate esters to acetylenic sulfones, followed by LDA-promoted intramolecular acylations, afforded cyclic enaminones that were readily converted into the corresponding 4-substituted 2-keto- or 2-hydroxyquinolizidines by stereoselective reduction and desulfonylation. This procedure was applied to the total synthesis of (-)-lasubine II from methyl (S)-(2-piperidyl)acetate and 2-(3,4-dimethoxyphenyl)-1-(p-toluenesulfonyl)ethyne. Similarly, methyl (+/-)-(2-piperidyl)acetate and 1-(p-toluenesulfonyl)propyne provided (+/-)-myrtine. 相似文献
98.
99.
Eklund P Andersson HO Kamali-Moghaddam M Sundström L Flensburg J 《Journal of chromatography. A》2003,990(1-2):179-188
This work deals with zone electrophoresis (ZE) separations of proteins on a poly(methyl methacrylate) chip with integrated conductivity detection. Experiments were performed in the cationic mode of the separation (pH 2.9) with a hydrodynamically closed separation compartment and suppressed electroosmotic flow. The test proteins reached the detector in less than 10 min under these working conditions and their migration times characterized excellent repeatabilities (0.1–0.6% RSD values). The chip-to-chip agreements of the migration times, evaluated from the ZE runs performed on three chips, were within 1.5%. The conductivity detection provided for protein, loaded on the chip at 10–1000 μg/ml concentrations, detection responses were characterized by 1–5% RSD values of their peak areas. Such migration and detection performances made a frame for reproducible baseline separations of a five-constituent mixture (cytochrome c, avidin, conalbumin, human hemoglobin and trypsin inhibitor). On the other hand, a high sample injection channel/separation compartment volume ratio of the chip (500 nl/8500 nl) restricted the resolution of proteins of very close effective mobilities in spite of the fact that in the initial phase of the separation an electric field stacking was applied. A maximum macroconstituent/trace constituent ratio attainable for proteins on the chip was assessed for cytochrome c (quantifiable when its concentration in the loaded sample was 10 μg/ml) and apo-transferrin (containing a trace constituent migrating in the position of cytochrome c detectable when the load of apo-transferrin was 2000 μg/ml). This assessment indicated that a ratio of 1000:1 is attainable with the aid of conductivity detection on the present chip. 相似文献
100.
H. Masood S. Yaqub F. Ahmed S. Ali S. Shahzadi 《Journal of the Iranian Chemical Society》2006,3(2):151-156
The organotin complexes of the general formulae R2SnL2, R2SnLCl and R3SnL where R = C4H9, C6H5, and C7H7 and L = 2-[(2,6-dichlorodiphenyl)amino]benzene acetate, were subjected to thermal decomposition by thermogravimetric analysis (TGA). The decomposition of these compounds occurs mostly in two steps. Kinetic parameters such as order of reaction (n), activation energy (Ea), enthalpy (ΔH?) and entropy (ΔS?) of activation were calculated by using the Coats and Horowitz methods. The calculated values are in good agreement with observed TG values that confirm the structural integrity of the complexes. 相似文献