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31.
Russian Journal of General Chemistry - The present study is devoted to functionalization of ethyl 2-{[3-cyano-6-(4-cyanophenyl)-4-(2,4-dichlorophenyl)pyridin-2-yl]oxy}acetate (1) by triazole-,...  相似文献   
32.
From the EtOAc and 1-BuOH fractions, three new ursane-type and four new lupane-type triterpenes, along with nine known glycosides and glycosyl esters of lupane-type were isolated from the leaves of Schefflera actinophylla. All the isolated compounds were obtained for the first time from this plant. The structures of the new triterpenes were determined through a combination of spectroscopic and chemical analyses.  相似文献   
33.
34.
Small hydrogen-bonded water clusters have received much attention and are the subject of both theoretical and chemical research. The crystalline molecular host provides an environment for the stabilization of various topologies of water clusters. The present article deals with (H2O) n clusters, identified/observed crystallographically in respective crystalline hydrates. The structural details of water decamers, octamers, hexamers, tetramers, and dimers are described systematically.  相似文献   
35.
The extract of Casimiroa edulis was investigated for antihypertensive activity. The ethanol and total alkaloids (in chloroform) extracts were found to have antihypertensive properties at doses of 500 and 200 mg/kg, respectively. Four quinolinone alkaloids were isolated and identified as: 2-(2′-hydroxy-4′-methoxyphenyl)-5,8-dimethoxy-3-propyl-1H-quinolin-4-one (1), 5,8-dimethoxy-2-(3′-methoxyphenyl)-3-propyl-1H-quinolin-4-one (2), 5,8-dimethoxy-2-(3′,4′-dimethoxyphenyl)-3-propyl-1H-quinolin-4-one (3), and 5,6-dimethoxy-2-(2′,5′,6′-trimethoxyphenyl)-1H-quinolin-4-one (4). Interestingly, compounds 1, 2, and 3 were found to be new alkaloids. The four isolated alkaloids showed antihypertensive activity at doses of 50, 100, 200, and 300 mg/kg, respectively. Published in Khimiya Prirodnykh Soedinenii, No. 5, pp. 473–476, September–October, 2007.  相似文献   
36.
A tetra-nuclear copper(II) complex [Cu4(C54H46N4O14)(OH)2] · 10H2O (1) has been synthesized starting from l-tyrosine, NaOH, 2,6-diformyl-4-methylphenol (dfp) and CuSO4 · 5H2O. Compound 1 crystallizes from an ethanol–water mixture in triclinic space group. In the crystal of 1, two binuclear copper units, related by a center of symmetry, are bridged by two hydroxo bridges and results in the formation of a tetra-nuclear {Cu4} structure. Five lattice water molecules, located in the asymmetric unit, interact among themselves and form an unusual form of a water nonamer. In the crystal, the water nonamer is again hydrogen bonded to the next nonamer forming a chainlike polymer. Each {Cu4} complex unit attaches four such water nonamer chains. Variable temperature magnetic data fit to the Bleaney–Bower’s equation with a Curie type of impurity of S = 0.5. The best fit of the magnetic data to this equation yielded 2J = −217, g = 2.019 and a TIP value of 60 × 10−6 cm3 mol−1.  相似文献   
37.
Shivaiah V  Das SK 《Inorganic chemistry》2005,44(24):8846-8854
Two Anderson-type heteropolyanion-supported copper phenanthroline complexes, [Al(OH)6Mo6O18[Cu(phen)(H2O)2]2]1+ (1c) and [Al(OH)6Mo6O18[Cu(phen)(H2O)Cl]2]1- (1a) complement their charges in one of the title compounds [Al(OH)6Mo6O18[Cu(phen)(H2O)2]2][Al(OH)6Mo6O18[Cu(phen)(H2O)Cl]2].5H2O [1c][1a].5 H2O 1. Similar charge complementarity exists in the chromium analogue, [Cr(OH)6Mo6O18[Cu(phen)(H2O)2]2][Cr(OH)6Mo6O18[Cu(phen)(H2O)Cl]2].5 H2O [2c][2a].5 H2O 2. The chloride coordination to copper centers of 1a and 2a makes the charge difference. In both compounds, the geometries around copper centers are distorted square pyramidal and those around aluminum/chromium centers are distorted octahedral. Three lattice waters, from the formation of intermolecular O-H.....O hydrogen bonds, have been shown to self-assemble into an "acyclic water trimer" in the crystals of both 1 and 2. The title compounds have been synthesized in a simple one pot aqueous wet-synthesis consisting of aluminum/chromium chloride, sodium molybdate, copper nitrate, phenanthroline, and hydrochloric acid, and characterized by elemental analyses, EDAX, IR, diffuse reflectance, EPR, TGA, and single-crystal X-ray diffraction. Both compounds crystallize in the triclinic space group P. Crystal data for 1: a = 10.7618(6), b = 15.0238(8), c = 15.6648(8) angstroms, alpha = 65.4570(10), beta = 83.4420(10), gamma = 71.3230(10), V = 2182.1(2) angstroms3. Crystal data for 2: a = 10.8867(5), b = 15.2504(7), c = 15.7022(7) angstroms, alpha = 64.9850(10), beta = 83.0430(10), gamma = 71.1570(10), V = 2235.47(18) angstroms3. In the electronic reflectance spectra, compounds 1 and 2 exhibit a broad d-d band at approximately 700 nm, which is a considerable shift with respect to the value of 650-660 nm for a square-pyramidal [Cu(phen)2L] complex, indicating the coordination of [M(OH)6Mo6O18]3- POM anions (as a ligand) to the monophenanthroline copper complexes to form POM-supported copper complexes 1c, 1a, 2c, and 2a. The ESR spectrum of compound 1 shows a typical axial signal for a Cu2+ (d9) system, and that of compound 2, containing both chromium(III) and copper(II) ions, may reveal a zero-field-splitting of the central Cr3+ ion of the Anderson anion, [Cr(OH)6Mo6O18]3-, with an intense peak for the Cu2+ ion.  相似文献   
38.
The blue mixed-crystal title compound Na15[MoMoO462H14 (H2O)70]0.5[MoMoO457H14 · (H2O)68]0.5 · ca. 400 H2O ≡ Na15[ 1 a ]0.5[ 1 b ]0.5 · ca. 400 H2O 1 , which crystallizes in the triclinic space group P 1 (a = 30.785(2), b = 32.958(2), c = 47.318(3) Å, α = 90.53(1), β = 89.86(1), γ = 96.85(1)°, V = 47665(6) Å3, Z = 2, Dcalc = 2.149 g cm–3), precipitates within one day when an acidic (pH ≈ 1) aqueous solution of sodium molybdate (because of the extremely high solubility of the reaction product used in relatively high concentration) is reduced by sodium dithionite. 1 contains hitherto unknown pure molybdenum-oxide based, nanosized, ring-shaped, crystallographically independent cluster anions of the type {Mo154} 1 a and {Mo152} 1 b , the lacunary-type analogue of 1 a . Using the same reducing agent but in the presence of a reagent with a high affinity to the specific {Mo2}-type building unit (also a leaving group) of 1 a , such as formic acid, the compound Na22[MoMoO442H14(H2O)58] · ca. 250 H2O 2 (space group P 1, a = 24.724(1), b = 35.726(2), c = 44.608(3) Å, α = 93.25(1), β = 93.51(1), γ = 106.72(1)°, V = 37552(4) Å3, Z = 2, Dcalc = 2.401 g cm–3) is obtained in which the giant rings, having four missing {Mo2} units compared to 1 a , are linked to chains. Until now, similar chain-type compounds could only be obtained using a non-well-defined synthetic method.  相似文献   
39.
New Pb(II), Mn(II), Hg(II), and Zn(II) complexes, derived from 4-(4-chlorophenyl)-1-(2-(phenylamino)acetyl)thiosemicarbazone, were synthesized. The compounds with general formulas, [Pb(H2L)2(OAc)2]ETOH.H2O, [Mn(H2L)(HL)]Cl, [Hg2(H2L)(OH)SO4], and [Zn(H2L)(HL)]Cl, were characterized by physicochemical and theoretical studies. X-ray diffraction studies showed a decrease in the crystalline size of compounds that were exposed to gamma irradiation (γ-irradiation). Thermal studies of the synthesized complexes showed thermal stability of the Mn(II) and Pb(II) complexes after γ-irradiation compared to those before γ–irradiation, while no changes in the Zn(II) and Hg(II) complexes were observed. The optimized geometric structures of the ligand and metal complexes are discussed regarding density functional theory calculations (DFT). The antimicrobial activities of the ligand and metal complexes against several bacterial and fungal stains were screened before and after irradiation. The Hg(II) complex has shown excellent antibacterial activity before and after γ-irradiation. In vitro cytotoxicity screening of the ligand and the Mn(II) and Zn(II) complexes before and after γ-irradiation disclosed that both the ligand and Mn(II) complex exhibited higher activity against human liver (Hep-G2) than Zn(II). Molecular docking was performed on the active site of MK-2 and showed good results.  相似文献   
40.
A dynamic model for optimal design quality and return policies   总被引:1,自引:0,他引:1  
A clearly explained and generous return policy has been established as a competitive weapon to enhance sales. From the firm’s point of view, a generous return policy will increase sales revenue, but will also increase cost due to increased likelihood of return. Design quality of the product has been used as a competitive weapon for a long time. This paper recognizes the relationship between design quality and price of the product, and the firm’s return policy. Quality level in the product would influence the amount of return directly. When the product quality is higher, the customer satisfaction rate will increase and the probability of return will decrease. We develop a profit-maximization model to jointly obtain optimal policies for the product quality level, price and the return policy over time. The model presented in this paper is dynamic in nature and considers the decisions as the product moves through the life cycle. We obtain a number of managerial guidelines for using marketing and operational strategy variables to obtain the maximum benefit from the market. We mention several future research possibilities.  相似文献   
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