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971.
972.
973.
《Journal of Coordination Chemistry》2012,65(10):1664-1675
Three coordination polymers, {[Co(C10H5N3O5)(H2O)2]·H2O}n (1), {[Mn3(C10H5N3O5)2Cl2(H2O)6]·2H2O}n (2), and {[Cu3(C10H4N3O5)2(H2O)3]·4H2O}n (3), based on a T-shaped tripodal ligand 4-(4,5-dicarboxy-1H-imidazol-2-yl)pyridine 1-oxide (H3DCImPyO), were synthesized under hydrothermal conditions. The polymers showed diverse coordination modes, being characterized by elemental analysis, infrared spectroscopy, and single-crystal X-ray structure analysis. In 1, the HDCImPyO2? generated a 1-D chain by adopting a μ2-kN, O : kN′, O′ coordination mode to bridge two Co(II) ions in two bis-N,O-chelating modes. In 2, the HDCImPyO2? adopted a μ3-kN, O : kO′, O′′ : O′′′ coordination mode to bridge two crystallographically independent Mn(II) ions, forming a 2-D hcb network with {63} topology. In 3, by adopting μ4-kN, O : kO′, O′′ : kN′′, O′′′ : O′′′′ coordination, DCImPyO3? bridged three crystallographically independent Cu(II) ions to form a 3-D framework having the stb topology. 相似文献
974.
《Journal of Coordination Chemistry》2012,65(15):2702-2711
Under hydrothermal conditions, reaction of Cu(II)/Cd(II) salts with 1,5-naphthalenedisulfonate (1,5-NDS) and 4,5-diazafluoren-9-one (dafo) afforded [Cu(dafo)2(1,5-NDS)]n (1) and [Cd(dafo)2(1,5-NDS)]n (2), respectively. The compounds were characterized by elemental analysis, IR, PXRD, TG-DSC, and single-crystal X-ray diffraction. Both 1 and 2, which are the first M(II)-1,5-NDS-dafo systems, exhibit 3-D supramolecular structures generated by 1-D chains via C–H?O hydrogen bonds and π–π interactions. Solid-state photoluminescence properties of both 1 and 2 were investigated with emission bands at 426–496?nm (λ ex?=?280, 270?nm for 1 and 2, respectively). 相似文献
975.
For solving large-scale unconstrained minimization problems, the nonlinear conjugate gradient method is welcome due to its simplicity, low storage, efficiency and nice convergence properties. Among all the methods in the framework, the conjugate gradient descent algorithm — CG_DESCENT is very popular, in which the generated directions descend automatically, and this nice property is independent of any line search used. In this paper, we generalize CG_DESCENT with two Barzilai–Borwein steplength reused cyclically. We show that the resulting algorithm owns attractive sufficient descent property and converges globally under some mild conditions. We test the proposed algorithm by using a large set of unconstrained problems with high dimensions in CUTEr library. The numerical comparisons with the state-of-the-art algorithm CG_DESCENT illustrate that the proposed method is effective, competitive, and promising. 相似文献
976.
977.
《Journal of Coordination Chemistry》2012,65(10):1737-1743
A 2-D coordination polymer with mixed ligands, [Zn2(BDC)(4,4′-bipy) (HCOO)2] (1) (BDC, 1,4-benzenedicarboxylate; 4,4′-bipy, 4,4′-bipyridine), has been synthesized by solvothermal reaction. Compound 1 provides the first coordination polymer structure constructed by bridging BDC, 4,4′-bipy, and formate. Both BDC and 4,4′-bipy link zincs alternatively, resulting in a zigzag coordination chain; adjacent chains are further linked by formates to form an infinite extended 2-D folding screen layer. The synthesis mechanism and fluorescence property are discussed. 相似文献
978.
This paper is devoted to the blow-up properties of solutions to the porous medium equations with a nonlocal boundary condition and a moving localized source.Conditions for the existence of global or bl... 相似文献
979.
研究了三维可压等熵Euler方程Cauchy问题光滑解的整体存在性.如果初值是一个常状态的小扰动并且初速度的旋度等于零,证明了三维可压等熵Euler方程Cauchy问题光滑解的整体存在性. 相似文献
980.