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本文报道铋(III)与不对称变色酸双偶氮衍生物之间的一类特殊反应──β型反应, 研究了试剂分子结构与反应性能的关系, 着重探讨铋(III)与偶氮氯膦-pN的β-型反应行为, 在高氯酸介质中, 铋(III)与上述试剂形成灵敏度很高的稳定β型配合物, λmax=713nm, εmax=9.84×10^4L·mol^-^1·cm^-^1, 并考察了反应酸度、显色剂浓度、有机溶剂(或表面活性剂)、显色温度及显色时间等对反应的影响, 测定了α和β型配合物的组成, 初步探索了α和β型配合物之间相互转化的规律。 相似文献
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The synergistic extractic extraction of lithium with a solution of o-phenylazophenols (HAX) and trioctylphosphine oxide (TOPO) or other trialkylphosphine oxide (TRPO, R = C8-10) in o-dichlorobenzene from aqueous solution of lithium hydroxide was reported. The structural effect of o-phenylazophenols on extraction of lithium has been examined. In the case of 1-(p-X-phenylazo)-2-naphthols, the HMO calculation shows that the charge density of azo nitrogen atom(the donor atom, denote azo N) and hydroxyl oxygen atom does not very apparently, so that the stability of their chelates with lithium has no obvious variations as well. In this case their ability to extract lithium is chiefly governed by the pKa. of the compound. The results of extraction prove that there is a linear correlation between the extraction constant Kex and pKa. However, for the second group of chelating agents, the change of their structure leads to the change of the change of both pKa and stability of chelates. The results of extraction and HMO calculation show that the stability of chelates is mainly influenced by the strength of the coordination bond, i.e. the larger the charge density of azo N (qN), the more stable the chelate will be. Therefore, their ability to extract lithium is roughly directly proportional to the stability of chelates and inversely to the pKa. the strength of coordination bond for the chelates can be experimentally measured by means of the strength of intramolecular hydrogen bond of chelating agent, ΔδOH (the diference of chemical shift of hydroxyl proton in free and bonded state). Therefore, the ratio, ΔδOH/pKa, can be used to evaluate the extraction ability of chelating agents to lithium. We find that it is approximately proportional to the distribution ratio (D). 相似文献
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Franco Cristiant Francesco A. Devillanova Angelo Diaz Francesco Isaia Gaetano Verani 《光谱学快报》2013,46(8):767-777
The 15N NMR chemical shifts and 1(15N-1H) coupling constants of a series of imidazolidine-2,4-dichalcogen (O, S) derivatives are reported.The 15N NMR chemical shifts show a linear correlatlon wlth the vNH stretchlng vlbratlons. The influence of the substitution of the oxygen at C2 and/or C4 with the sulphur, and of the hydrogen at C5 wlth the methyls and phenyls has been considered. The 1J(15N-1H)'s found In thls serles of molecules agrees well with the expected values. 相似文献
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采用Si(OCH~3)~4化学气相沉积方法精细调变HZSM-5孔径,焙烧后在沸石外表面上沉积一薄层氧化硅,使沸石孔口有控制地被缩小。制备了一系列氧化硅沉积量不同的SiHZSM-5沸石,并用红外光谱,NH~3-TPD和吸附方法对其进行表征,结果表明沸石骨架结构,内孔孔容和内表面性质基本不变。测定了SiHZSM-5沸石对于二甲苯和甲酚异构体的择形吸附性能,发现在沉积量适当的SiHZSM-5沸石上能够成功地实现对二甲苯和对甲酚的择形选择吸附分离,因为复合孔口缩小后将大的间位异构体排除在外,而沸石总吸附容量仍保持较高水平。 相似文献
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DNA碱基的电子相关效应 总被引:3,自引:0,他引:3
分别在Hartree-Fock和二级Moller-Plesset微扰理论MP2的电子相关校正水平, 用6-31G^*^*基函数对四种DNA碱基胞嘧啶、胸腺嘧啶、鸟嘌呤和腺嘌呤的能量、偶极矩、电荷分布和分子静电势等性质进行了系统的从头计算研究。其中, 采用Z矢量方法在波函数中加入MP2级别的电子相关校正; 分别用Mulliken布居分析、静电势导出电荷CHELPG以及自然布居分析NPA方法计算分子中原子电荷。在上述计算结果的基础上, 系统地分析了DNA碱基的电子相关效应。 相似文献
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羿喹啉及其衍生物的电子结构与缓蚀性能关系的研究 总被引:6,自引:0,他引:6
本文在30℃, 1.0mol.dm^-3 HCl溶液中用电化学方法测定了异喹啉及其羟基,羧基衍生物对Fe电极的缓蚀效率。并用HMO和CNDO/2方法计算了这些化合物的量子化学参数, 发现异喹啉及其衍生物分子中氮原子电荷和π净电荷越小, 缓蚀性能越好; 随着这些化合物异喹啉环中吡啶环上原子电荷之和的增大, 缓蚀性能提高; 吡啶环亲核前沿电荷与缓蚀效率有很好的线性关系, 提出了这类缓蚀剂分子可能呈平卧方式吸附于金属电极表面, 从而起缓蚀作用, 预测了五个新分子的缓蚀性能。 相似文献
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对完全型硼烷BnHn^2^-(n=4-12)及其全卤代分子BnCln^2^-作了EH系列的计算.通过能级比较,讨论了卤代硼烷以中性价态稳定存在的原因;根据HOMO-LUMO差,排列了稳定性次序,并由重叠布居计算值,对比了B-B键长数据的变化趋势,估计了未知产物的各类B-B键长. 相似文献