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401.
Ayta Gürhan Gke Süleyman Gülcemal Muhittin Aygün Bekir etinkaya Orhan Büyükgüngr 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(11):m535-m537
The title compound, [PdBr2(C21H13F5N2)2], crystallizes with two independent centrosymmetric conformational isomers having a square‐planar coordination at the Pd atom. The conformational isomers differ by the ligands having a cis or trans orientation of their benzyl and pentafluorobenzyl rings with respect to the benzimidazole ring plane. The benzimidazole rings are rotated with respect to the coordination plane of the metal by 79.1 (2) and 75.2 (1)° for molecules A and B, respectively. The Pd—Br bond lengths are 2.4218 (8) and 2.4407 (10) Å for molecules A and B, respectively, and the Pd—C bond lengths are 2.030 (8) and 2.018 (9) Å. The crystal structure contains two types of C—H⋯F and one type of C—H⋯Br intramolecular contact, as well as C—H⋯π interactions. 相似文献
402.
Synthesis, structure, and catalytic oxidation chemistry from the first oxo-imido Schiff base metal complexes 总被引:1,自引:0,他引:1
The molybdenum oxo-imido complex, [Mo(O)(NtBu)Cl2(dme)] (1), was obtained from the reaction between [MoO2Cl2(dme)] and [Mo(NtBu)2Cl2(dme)]. Reactions between [Mo(O)(NR)Cl2(dme)] (where R = tBu or 2,6-iPr2C6H3) and the disodium Schiff base compounds Na(2)(3,5-tBu2)2salen, Na(2)(3,5-tBu2)2salpen, and Na(2)(7-Me)2salen afforded the first oxo-imido transition metal Schiff base complexes: [Mo(O)(NtBu)[(3,5-tBu2)2salen]] (2), [Mo(O)(NtBu)[(3,5-tBu2)2salpen]] (3), and [Mo(O)(N-2,6-iPr2C6H3)[(7-Me)2salen]] (4), respectively. The compounds [Mo(NtBu)2[(3,5-tBu2)2salpen]] (5) from [Mo(NtBu)2(NHtBu)2] and [Mo(N-2,6-iPr2C6H3)(2)[(7-Me)2salen]](6) from [Mo(N-2,6-iPr2C6H3)(2)(NHtBu)2] (7) are also reported. Compounds 1-7 were characterized by NMR, IR, and FAB mass spectroscopy while compounds 3, 4, and 5 were additionally characterized by X-ray crystallography. In conjunction with tBuOOH as oxidant, compound 3 is a catalyst for the oxidation of benzyl alcohol to benzaldehyde and cis-cyclooctene and 1-octene to the corresponding epoxides. 相似文献
403.
Muharrem Diner Namk
zdemir Süleyman Gülcemal Bekir etinkaya Orhan Büyükgüngr 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(6):m252-m254
The title complex, [RhBr(C8H12)(C24H19F5N2)], has a distorted pseudo‐square‐planar geometry. The Rh—C bond distance between the N‐heterocyclic ligand and the metal atom is 2.022 (3) Å. The angle between the carbene heterocycle and the coordination plane is 75.60 (11)°. It is shown that the average Rh—C(cyclooctadiene) distance is linearly dependent on the Rh—C(imidazole) distance in this type of compound. The crystal structure contains one intramolecular and two intermolecular types of C—H⋯F interactions, as well as one type of π–π stacking interaction. 相似文献
404.
The dithizone-anchored poly (EGDMA-HEMA) microbeads were prepared for the removal of heavy metal ions (i.e. cadmium, mercury, chromium and lead) from aqueous media containing different amounts of these ions (25-500 ppm) and at different pH values (2.0-8.0). The maximum adsorptions of heavy metal ions onto the dithizone-anchored microbeads from their solutions was 18.3, Cd(II); 43.1, Hg(II); 62.2, Cr(III) and 155.2 mg g(-1) for Pb(II). Competition between heavy metal ions (in the case of adsorption from mixture) yielded adsorption capacities of 9.7, Cd(II); 28.7, Hg(II); 17.6, Cr(III) and 38.3 mg g(-1) for Pb(II). The same affinity order was observed under non-competitive and competitive adsorption, i.e. Cr(III)>Pb(II)>Hg(II)>Cd(II). The adsorption of heavy metal ions increased with increasing pH and reached a plateaue value at around pH 5.0. Heavy metal ion adsorption from artificial wastewater was also studied. The adsorption capacities are 4.3, Cd(II); 13.2, Hg(II); 7.2, Cr(III) and 16.4 mg g(-1) for Pb(II). Desorption of heavy metal ions was achieved using 0.1 M HNO(3). The dithizone-anchored microbeads are suitable for repeated use (for more than five cycles) without noticeable loss of capacity. 相似文献
405.
The reaction of 1‐alkylbenzimidazole derivatives with o‐/p‐di(chloromethyl)benzene results in the formation of the new o‐/p‐xylyl‐linked bis(benzimidazolium) salts, 1 and 2, respectively. The salts were characterized by NMR spectroscopy and elemental analysis. The in situ prepared complexes derived from Pd(OAc)2–1 and 2 exhibit catalytic activity (61–98%), to give the Heck coupling products of aryl bromides and styrene. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
406.
In this paper, we have investigated the real-world task of recognizing biological concepts in DNA sequences. Recognizing promoters in strings that represent nucleotides (one of A, G, T, or C) has been performed using a novel approach based on combining feature selection (FS) and least square support vector machine (LSSVM). Dimensionality of Escherichia coli promoter gene sequences dataset has 57 attributes and 106 samples including 53 promoters and 53 non-promoters. The proposed system consists of two parts. Firstly, we have used the FS process to reduce the dimensionality of E. coli promoter gene sequences dataset that has 57 attributes. So the dimensionality of this dataset has been reduced to 4 attributes by means of FS process.Secondly, LSSVM classifier algorithm has been run to estimation the E. coli promoter gene sequences. In order to show the performance of the proposed system, we have used the success rate, sensitivity and specificity analysis, 10-fold cross validation, and confusion matrix. Whilst only LSSVM classifier has been obtained 80% success rate using 10-fold cross validation, the proposed system has been obtained 100% success rate for same condition. These obtained results indicate that the proposed approach improve the success rate in recognizing promoters in strings that represent nucleotides. 相似文献
407.
Four crown ether substituted cofacial bis-phthalocyanines were prepared by the cyclic condensation of dihydroxy groups of pentaerythritol moieties of phthalocyanine with tetraethyleneglycol ditosylate in the presence of NaH as base in refluxing THF. 相似文献
408.
Reaction of ortho‐xylylbis(N‐2,4,6‐trimethylbenzylimidazolinium); xylylbis(N‐butylimidazolinium) and para‐xylylbis(N‐2,4,6‐trimethylbenzylimidazolinium); xylylbis(N‐butylimidazolinium) salts with KOBut and [RhCl(COD)]2 yields ortho‐ and para‐xylylbis{(N‐alkylimidazolidin‐2‐ylidene)chloro(η4‐1,5‐cyclooctadiene) rho dium(I)} complexes (2a–d). All compounds synthesized were characterized by elemental analysis and NMR spectroscopy, and the molecular structures of the 2a and 2d were determined by X‐ray crystallography. Triethylsilane reacts with acetophenone derivatives in the presence of catalytic amount of the new rhodium(I)–carbene complexes (2a–d), to give the corresponding silylethers in good yields (83–99%). Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
409.
In this study, black cumin seed cake was transformed into liquid and solid products via pyrolysis method at 300, 400 and 500?°C with Ca(OH)2, Al2O3, SnCl4.5H2O catalysts and without catalyst. The obtained liquid and solid products were examined with GC-MS, Elemental, FT-IR, 1H NMR and SEM analysis methods. The highest liquid product yield was obtained as 30% in the presence of Al2O3 catalyst. All catalysts were found to be effective on conversion. According to the results of the elemental analysis of the liquid products obtained at the end of the experiments, HHV values were found between 32.44 and 36.19?Mj/kg. According to the results of GC-MS analysis of the liquid products, in total, 77, 61 and 66 pieces of compounds consist of monoaromatics, aliphatics, oxygenated compounds with different properties were obtained at 300, 400 and 500?°C reaction temperatures respectively. The results of the FT-IR and 1H NMR that are used to examine the liquid products support the results of GC-MS. 相似文献
410.
A new method of determining elastoplastic properties of a beam from an experimentally given value T?T(φ) of torque (or torsional rigidity), during the quasistatic process of torsion, given by the angle of twist φ∈[φ*,φ*], is proposed. The mathematical model leads to the inverse problem of determining the unknown coefficient g=g(ξ2), ξ?|∇u|, of the non-linear differential equation −∇(g(|∇u|2)∇u)=2φ, x∈Ω⊂R2. The inversion method is based on the parametrization of the unknown coefficient, according to the discrete values of the gradient ξ?|∇u|. Within the range of J2-deformation theory, it is shown that the considered inverse coefficient problem is an ill-conditioned one. A numerical reconstruction algorithm based on parametrization of the unknown coefficient g=g(ξ2), with optimal selection of the experimentally given data Tm?T(φm), is proposed as a new regularization scheme for the considered inverse problem. Numerical results with noise free and noisy data illustrate applicability and high accuracy of the proposed method. 相似文献