8-氮鸟嘌呤与铜(Ⅱ)的络合吸附波

用单扫描极谱法研究了8-氮鸟嘌呤(8-AG)与Cu2+形成络合物的条件,测定了该络合物有关的特征常数。在pH 3.00的HAc-NH4Ac缓冲溶液中,8-AG与Cu2+可以形成1∶1的络合物。该络合物产生一个不可逆吸附还原波,有1个电子和1个质子参与了电极反应,该络合物的条件稳定常数为5.73×105,反应活化能为12.1 kJ/mol,电极反应速率常数为1.04×10-4cm/s。     

用微分脉冲伏安法测定铅(Ⅱ)-精氨酸及铅(Ⅱ)-丝氨酸络合物稳定常数

本文介绍了用微分脉冲伏安法以悬汞电极为工作电极测定铅(Ⅱ)-精氨酸及铅(Ⅱ)-丝氨酸络合物稳定常数。研究了仪器参数及实验条件对测定的影响,在20℃、离子强度为0.50M NaNO_3介质条件下,测得了铅(Ⅱ)-精氨酸及铅(Ⅱ)-丝氨酸络合物的累积稳定常数。     

用铅离子选择电极研究难溶化合物组分的络合平衡

难溶化合物组分络合平衡的研究是比较困难的,因为溶解度很小,在不产生沉淀的稀溶液中测定其平衡组分的方法必须足够灵敏和准确。截至目前为止,只是对少数这类物质的稳定常数作过测定。在所报导的离子选择电极测定法中电极的校正均采用分析浓度校正曲线,相对于金属离子浓度,配位体为不足量,因此只能测得一级络合物的稳定常数。由于研究络合平衡时所要求测定的正是自由离子浓度,因此本文提出用铅离子缓冲溶液作铅电极的校正曲线测定草酸铅和硫酸铅络合物的稳定常数。该法容许相对于铅离子浓度配位体大     

水溶性稀土卟啉络合物的合成及电化学行为

对水溶性稀土卟啉络合物的合成、结构、稳定性及其电化学特性进行了系统研究，测定了络合物的稳定常数，讨论了稀土卟啉络合物的电极反应机理；对于镧系卟啉络合物，从Ｔｂ到Ｙｂ随着原子序数的递增，重稀土卟啉络合物的稳定性及还原性不断增强，还原峰电位不断正移，并从理论上解释了该规律。     

海水中重金属离子络合形态的研究(Ⅰ)——二阶导数卷积悬汞电极溶出伏安法

本文推导了络合体系中悬汞电极二阶导数卷积阳极溶出峰电势与络合物累积稳定常数的关系式,在模拟海水离子强度溶液中,测定了一系列简单金属离子及其络合物的溶出峰电势差,用电子计算机进行数学回归分析作曲线拟合,求得了Cd(Ⅱ)-SO₄²络合体系的各级累积稳定常数,并对海水中镉(Ⅱ)的存在形态作了综合估算。     

阳离子交换法和溶解度法测定溶液中混合型络合物稳定常数的一般处理

离子交换法测定溶液中络合物稳定常数是近十几年来才开始的,溶解度法是测定络合物稳定常数的经典方法之一,均有专论。溶液中混合型络合物稳定常数的测定也是近十几年才开始的,国内有过评介。但用阳离子交换法和溶解度法测定溶液中混合型络合物的稳定常数还未见报导。最近徐光宪等用萃取法以作图外推法测得混合型络合物稳定常数。本文尝试推导了用阳离子交换法和溶解度测定单核双配位体络合物稳定常数的有关公式。     

溶液中络合物的分步稳定常数与配位数间的关系

自从本世纪初布德兰德(Bodlader)等首先测定了铜、银络合物的稳定常数起,迄今已有60余年的历史。目前已经积累了相当数量的各种络合物的稳定常数。但对络合物的分步稳定常数间关系的研究,或对络合物分步稳定常数随配位数增加而改变规律的研究为数不多。雅齐米尔斯基曾指出,络合物分步稳定常数间的关系是一个相当重要的问题。可以说     

电位法测定酸解离常数和络合物稳定常数的基本原理和方法(Ⅰ)

应广大读者的要求,本刊开辟了《基础知识讲座》。有机试剂、掩蔽剂等的解离常数和络合物稳定常数对它们的合理使用有很大指导意义,因而愈来愈引起分析化学工作者的重视。不过,测定方法种类繁多,繁简难易相差极大,似乎无所适从。为此,本刊约请北京医学院药学系王夔教授撰写了酸“解离常数和络合物稳定常数的测定”一文,试图向分析化学工作者介绍电位法及光度法测定有关平衡常数的原理和方法。全文分五部分:(Ⅰ)电位法测定酸解离常数和络合物稳定常数的基本原理和方法;(Ⅱ)电位法测定多元酸解离常数;(Ⅲ)电位法测定络合物稳定常数;(Ⅳ)光度法测定解离常数和稳定常数;(Ⅴ)几种特殊情况(易水解金属络合物、混合配体络合物、极稳定络合物等)。本刊将陆续刊载。     

离子交换平衡法测定络合物稳定常数

本文介绍和评价了测定络合物稳定常数的离子交换平衡法,特别注重了腐殖酸络合物稳定常数的测定。     

氟-铝络合滴定计算分析法测定乙醇-水溶液介质中的铝

导出了氟离子标准溶液滴定铝离子的络合滴定计算分析的数学模型。以氟离子选择性电极作指示电极,利用氟离子与铝离子在乙醇-水溶液中产生沉淀,仅形成3种络合物的现象,先计算出3个条件累积稳定常数,再计算出铝离子的分析浓度。通过氢氧化铝的条件溶度积常数,求出溶液控制的pH值约为4．7。讨论了滴定数据的位置对测定结果的影响。     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

Synthesis of phenolic components of Grains of Paradise

Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.     

Summary of development of the theory of stability of colloids and thin films

In this review, the research of the author in the field of colloidal systems is summarized. The factors influencing colloidal stability are systematized and analyzed. Examples are presented to illustrate the practical utilization of the theory of stability of colloids and thin films.This review was prepared on the basis of the works of the author, which were awarded the State Premium for 1991 in the field of science and technology, chemistry section.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1708–1717, August, 1992.     

Study of hydration of two cements of different strengths

Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, M_o, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700^oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.     

氯氧化镁生成热的研究

用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。     

Thermodynamics of the formation of oxosulfides of rare-earth elements

The enthalpies of solution of several oxosulfides of rare-earth elements and the high-temperature enthalpies of oxosulfides and oxosulfates of lanthanum and yttrium were measured using solution calorimetry and high-temperature microcalorimetry techniques. Standard enthalpies of formation and some thermodynamic properties of oxosulfides and oxosulfates were calculated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2 pp. 294–297, February, 1997.     

探究“铁的锈蚀条件”实验创新设计

设计了铁的锈蚀实验,说明了铁钉的处理方法,增加了温度、酸、碱的影响条件,实现了铁跟蒸馏水及空气中氧气快速反应而生锈,使实验在5 min左右就能够得到准确的结果。