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991.
Late transition metal (nickel, cobalt) complexes (1, 2) with β‐ketoamine ligand (L) based on the pyrazolone derivative are synthesized by condensing 1‐phenyl‐3‐methyl‐4‐benzoyl‐5‐pyrazolone with p‐fluoroaniline, and then treating the β‐ketoamine (L) produced with the respective metal halide. The bis(β‐ketoamine)metal complexes can act as catalyst precursors for norbornene polymerization with activation by methylaluminoxane. The effects of the central metal variation in the complex on catalyst activities and polymer microstructure are described. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
992.
Xiao‐Hui Liu Gui‐Bao Zhang Xian‐Feng Lu Jing‐Yu Liu Ding Pan Yue‐Sheng Li 《Journal of polymer science. Part A, Polymer chemistry》2006,44(1):490-498
Reversible addition–fragmentation chain transfer polymerization has been successfully applied to polymerize acrylonitrile with dibenzyl trithiocarbonate as the chain‐transfer agent. The key to success is ascribed to the improvement of the interchange frequency between dormant and active species through the reduction of the activation energy for the fragmentation of the intermediate. The influence of several experimental parameters, such as the molar ratio of the chain‐transfer agent to the initiator [azobis(isobutyronitrile)], the molar ratio of the monomer to the chain‐transfer agent, and the monomer concentration, on the polymerization kinetics and the molecular weight as well as the polydispersity has been investigated in detail. Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry and 1H NMR analyses have confirmed the chain‐end functionality of the resultant polymer. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 490–498, 2006 相似文献
993.
Gui‐Hua Lin 《Mathematical Methods in the Applied Sciences》2007,30(17):2179-2195
In this paper, we suggest a new relaxation method for solving mathematical programs with complementarity constraints. This method can be regarded as a modification of a method proposed in a recent paper (J. Opt. Theory Appl. 2003; 118 :81–116). We show that the main results remain true for the modified method and particularly, some conditions assumed in the previous paper can be removed. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
994.
Li Gui CHEN Zhi Lan LIU Ying Jun CHEN Ren Xi ZHUO 《中国化学快报》2005,16(12):1652-1654
Konjac glucomannan (KGM) was crosslinked with sodium tripolyphosphate (STPP) to synthesize hydrogels. The crosslinking reaction was confirmed by FT-IR. The results of degradation test show that the hydrogels retain the enzymatic degradation character of KGM and can be degraded for 74.45% in 5 days by cellulase E0240. 相似文献
995.
Zhen‐Feng Zhang Jian‐Ge Wang Si‐Qian Wang Gui‐Rong Qu 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(10):o565-o567
In each of methyl 2‐methyl‐5‐oxo‐2‐pyrroline‐3‐carboxylate, C7H9NO3, and 3‐acetyl‐2‐methyl‐2‐pyrrolin‐5‐one, C7H9NO2, the pyrrolinone ring is planar. In each structure, molecules are linked into simple chains by way of a single N—H...O hydrogen bond. 相似文献
996.
997.
Sufficient conditions are obtained for the existence and global exponential stability of a unique periodic solution of a class of neural networks with impulses by using Mawhin’s continuation theorem of coincidence degree theory and constructing Lyapunov functions. An illustrative example is given to demonstrate the effectiveness of the obtained results. 相似文献
998.
本文合成了新型的含有乙酰氧基的2-苯乙烯基苯并噻唑。研究了此类化合物在固态和溶液中的荧光特性。结果表明,乙酰氧基是一种很有趣的取代基,在甲苯溶液中具有给电子特性,而在多晶粉末中由于分子间相互作用使之具有吸电子特性,导致发射谱和激发谱中的长波带蓝移。 相似文献
999.
本文报道新合成的五种Schiff碱四齿螯合剂,二种五齿Schiff碱螯合剂及相应的钴(Ⅰ)螯合物。并在-20℃下进行了可逆载氧功能试验,得到了组成为Co(Ⅱ)L·O_2和Co(Ⅱ)L·PY·O_2的两类分子氧加合物。并用元素分析,电子光谱,IR,~1H NMR,TGA,磁化率和分子量测定等方法,确定了化合物的组成和分子结构式。还讨论了影响1:1钴氧加合物的稳定性及可逆载氧速度的因素。 相似文献
1000.
Summary 2-Thenoyltrifluoroacetone isonicotinoyl hydra/one (H2L), made by condensation of 2-thenoyltrifluoroacetone(TTA) with isonicotinic acid hydrazide, and its transition metal complexes were prepared. H2L functions as a tetradentate ligand for divalent metal ions, but as a tridentate ligand for trivalent metal ions, taking part in coordination in both mono- and divalent anions. Antioxidative tests were made to examine the elimination action for H2L and the complexes towards superoxide O
inf2
sup–.
and hydroxyl OH. radicals, which confirmed the efficient antioxidative action towards these radicals. 相似文献