排序方式: 共有128条查询结果,搜索用时 178 毫秒
71.
在25℃, I=0.1mol.dm^-^3NaClO4的条件下,在混合溶剂[50%(υ/υ)二氧六环和70%(υ/υ)乙醇]中用pH法测定了N,N'-双(对位取代苯基)乙二胺的质子化常数及其与铜(II),镍(II)生成二元配合物的生成常数.结果表明:在配位体的质子化常数与配合物的生成常数之间,在配位体的σ'值与Hammett方程中的取代基常数σ之间,以及稳定化因子S~f与σ值之间,均存在着良好的线性关系.从实验进一步验证了在配位化学中直线自由能关系存在的普遍性. 相似文献
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The kinetics of enantioselective hydrogenation of methyl acetoacetate using Raney nickel modified by (2R,3R)-(+)-tartaric acid were studied, thereby focusing on the effects of the reaction conditions on the enantioselectivity. Reactions were carried out in a liquid phase under atmospheric and increased hydrogen pressure. The reaction course was described by the exponential kinetics model and by Langmuir-Hinshelwood kinetics assuming the existence of two types of active sites on the catalyst surface, selective and non-selective. Using Langmuir-Hinshelwood kinetics, the acquired parameters were used for discussion of the effects of the reaction conditions on the enantioselectivity and the mechanism of the enantioselective hydrogenation. 相似文献
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Cu-Ni-Mg-Al-CO3四元水滑石的合成及结构分析 总被引:10,自引:0,他引:10
以Cu(NO3)2·2H2O,Ni(NO3)2·6H2O,Mg(NO3)2·6H2O和Al(NO3)3·9H2O为原料 ,以NaOH和Na2CO3为沉淀剂,采用成核/晶化隔离法合成了Cu-Ni-Mg-Al-CO3四元 水滑石,通过XRD,FT-IR,TG-DTA,ICP等手段对样品进行测试和表征,并且对 水滑石结构的层板和层间阴离子相互作用进行分析和讨论。结果表明,控制Cu^2+ 离子与其它二价金属离子的配比,可制备晶体结构规整的M(Ⅱ)4M(Ⅲ)2(OH) 12CO3·4H2O型水滑石;Cu^2+离子的引入导致了明显的Jahn-Teller效应;且随 Mg^2+量的增加,使得这种效应更加显著,另一方面Mg^2+量的增加有利于Cu-Ni- Mg-Al-CO3四元水滑石晶体在a方向上生长,增强其热稳定性。 相似文献
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邻香兰素甘氨酸三吡啶合Ni(II)的合成、性质、晶体结构及热分解动力学 总被引:5,自引:0,他引:5
本文报道了邻香兰素甘氨酸三吡啶合Ni(II)的合成、性质、晶体结构及热分解动力学。晶体的X射线分析结果表明, 该晶体为单斜晶系, 空间群为C2/c,a=3.3549(6), b=1.1396(4), c=1.4555(5)nm, β=113.96(3)°, v=5.086.nm^3,Mr=526.21, z=8, Do=1.37g.cm^-^3, μ=806cm^-^1, F=(000)=2200。对配合物第一步热分解过程进行了非等温动力学研究, 其机理为球对称的三维扩散。 相似文献
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11,12,13-三甲基-1,4,7,10-四氮杂十三环-10,13-二烯-镍(II)配合物催化的新型振荡化学反应 总被引:3,自引:0,他引:3
本文报道了一种新型振荡化学反应体系--BrOˉ~3-MA-H2SO4-[Ni(L-H)]X(X为配阴离子)体系, 其中MA为丙二酸, L代表题给大环11,12,13-三甲基-1,4,7,10-四氮杂十三 环-10, 13-二烯。测得了该体系发生振荡的组分浓度范围; 研究了各物浓度、自由基抑制剂和还原剂对振荡反应的影响; 还测得了振荡的轨迹为螺旋线而非极限环, 由于催化剂消耗振荡衰减; 初步提出了振荡反应发生的可能机理。 相似文献
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含二茂铁基为臂的三角架型过渡金属配合物的研究 总被引:2,自引:0,他引:2
本文利用2,2',2'-三氨基三乙胺(tren)与二茂铁甲醛(FcCHO)的Schiff碱缩合产物(L)为配体合成了十个三角型过渡金属配合物:[MLX]^2+/1+,M=Zn^2+,Cu^2+,Ni^2+,Co^2+=和MN^2+,X=H~2O或OAc^-,并用电子光谱、红外光谱和顺磁=共振光谱对配合物的结构进行了表征.测定了四个化合物的变温磁化率,实验结果表明二茂铁中磁性的Fe(Ⅱ)离子对配合物的磁性影响很小,整个化合物只显示中心离子的磁性. 相似文献
80.
Qi-xingZhang Shao-quanLin Zhi-yongWu Hai-huaWang 《高分子科学》2004,(4):313-319
(α-Diimine)nickel(Ⅱ) {[C6H5 -N = C(CH3)-C(CH3) = N -C6H5]NiBr2}-TiCl4 abbreviated as NiL-TiCl4 combined catalyst which is supported on MgCl2-SiO2 carrier has been prepared, by using alkyl aluminum (AIR3) as the cocatalyst in place of methylaluminoxane (MAO) to catalyze ethylene oligomerization and copolymerization in situ. The influences of procedure for supporting NiL-TiCI4, the molar ratio of NiL to TiCI4, cocatalyst type and polymerization temperature on the catalytic performance were studied. The degree of branching and the composition of the branched chain of polymers produced have been investigated by IR and ^13C-NMR spectra. The results show that the combined catalyst can synthesize the branched polyethylene with various banched chains .The polymerization reaction was monitored by gas chromatography and mass spectrometry (GC-MS). The results show that this catalyst promotes the oligomerization and copolymerization in situ for ethylene. 相似文献