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金属络合物对弹性体老化的影响
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作者 D.Bruck St.David 王启生 《橡胶参考资料》 1997年第8期51-55,共5页
前言众所周知,重金属化合物通过催化氢过氧化物分解或与聚合物直接反应能引发橡胶的自动氧化。这种化合物对橡胶老化的作用能力到目前为止还无法推测。
关键词 金属铬合物 弹性体 老化
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Synthesis and Crystal Structure of a Cyano- bridged Bimetallic Complex[La(DMSO)_3(H_2O)_3- Cr(CN)_6]·H_2O (DMSO = Dimethylsulfoxide) with One-dimensional Chain Molecular Structure
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作者 梁淑惠 车云霞 郑吉民 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2004年第11期1226-1229,共4页
The title complex [La(DMSO)3(H2O)3Cr(CN)6]H2O was obtained by the reaction of LaCl37H2O, DMSO and K3[Cr(CN)6] in aqueous solution on a hot water bath. The crystal crystallizes in orthorhombic, space group P212121 with... The title complex [La(DMSO)3(H2O)3Cr(CN)6]H2O was obtained by the reaction of LaCl37H2O, DMSO and K3[Cr(CN)6] in aqueous solution on a hot water bath. The crystal crystallizes in orthorhombic, space group P212121 with a = 9.827(3), b = 15.037(4), c = 17.633(5) ? C12H26CrLaN6O7S3, Mr = 653.48, Z = 4, V = 2605.7(13) ?, Dc = 1.666 g/m3, (MoKa) = 2.314 mm-1, F(000) = 1300, R = 0.0205 and wR = 0.0481 for 5038 observed reflec- tions (I > 2s(I)). La3+ ion is eight-coordinated by three DMSO molecules, three H2O molecules and two [Cr(CN)6]3- units. The structure of the title complex possesses a cyano-bridged one- dimensional zigzag chain structure with alternating La(DMSO)3(H2O)3 and Cr(CN)6 moieties, which are linked by some hydrogen bonds to form a 3D network structure. 展开更多
关键词 crystal structure synthesis cyano-bridged bimetallic complex hydrogen bond
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Some Transition Metal Complexes Bearing Artemisinin Derivatives and (N-N-O) Tridentate Chromium (Ⅲ) Complexes Ligated by 2-benzolmidazo-yl-6-acetyl. pyridines for Catalytic Behaviour towards Ethylene
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作者 Joshua Ayoola Obaleye Saliu Alao Amolegbe +2 位作者 Sheriff Adewuyi Wenhua Sun Margaret Damilola Oshodi 《Journal of Chemistry and Chemical Engineering》 2010年第12期23-32,共10页
Interventions of metal complexes in the area of metallopharrneceutical and polymer sciences play a great economic importance to human challenges. Complexation behavior of some artemisinin derivatives with late transit... Interventions of metal complexes in the area of metallopharrneceutical and polymer sciences play a great economic importance to human challenges. Complexation behavior of some artemisinin derivatives with late transition metals and chromium-benzoimidazoylpyridine analogues have been investigated. The Fe(Ⅲ), Zn(Ⅱ) and Cd(Ⅱ) complexes of artesunate and artemether and that of chromium-benzimidazoyl pyridine were synthesized with molar ratio of metal to ligand between 1:1 and 1:2. Structural elucidation using X-ray analysis and other characterization of the complexes (AAS, IR, UV, E.A, NMR) were carried out to explore the coordination affinity of them viz-a viz bonding, geometries and elemental composition. The IR absorption revealed that artesunate acts as monodentate specie through carbonyl group on coordination. However, its bidentate mode was also observed with carboxylic group acting as C=O and C-O bonding when deprotonation happened. Artemether (L2) was synthesized using artesunate and its structure was confirmed by single crystal X-ray crystallography as well as its Zn(Ⅱ) complex exhibiting a square planar geometry. A series of 2-benzoimidazoylpyridine derivates (L3-L6) and their chromium complexes were synthesized and characterized. In the presence of methylaluminoxane (MAO), all chromium complexes show good activity for ethylene oligomerization and polymerization whereas with diethylaluminium chloride (Et2AlCl2) the complexes show moderate activity. The distribution of oligomers obtained follows Schulz- Flory rules with high selectivity for α-olefins. The combined productivity (meaning both activities of ethylene oligomerization and polymerization) are improved with increasing ethylene pressure. The results show that the reaction conditions greatly affect the properties of the polymer such as molecular weight distribution and melting point(Tm) with extremely broad molecular weight distributions. With elevating reaction temperature from 0 to 60 ℃, the melting point (Tin) of resultant polyethylene decreased rapidly from 134 ℃ to 70 ℃. 展开更多
关键词 Artemisinin pyridine ETHYLENE co-catalyst.
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