结晶十六烷基三甲基溴化铵烷基链构象的红外光谱研究

在290-400K的温度范围内用红外光谱法在分子水平上考察了结晶十六烷基三甲基溴化铵的分子链构象随温度的变化。结果表明:在343K以下分子烷基链主要以全反式构象相互平行排列,仅在链末端有少量TG式构象存在;当温度高于343K时,分子链中有GTG′式构象出现且链间相互作用开始减弱,但分子链轴仍保持相互平行排列;当温度高于373K时,TG和GTG′式构象数量显著增加,同时GTG和GG式构象大量出现,烷基链轴的线性结构被破坏且分子链间相互作用变得很弱。

ELECTROCHEMICAL-BEHAVIOR OF N-METHYL-N'-HEXADECYLVIOLOGEN MONOLAYERS ON SILVER ELECTRODES - EFFECTS OF COUNTERIONS

N-Methyl-N'-hexadecylviologen (C16MV) has been the subject of several electrochemical and spectroelectrochemical studies which characterized the species present in various redox states for C16MV monolayers on silver electrode surfaces. Both self-assembled monolayers (SA) and Langmuir-Blodgett (LB) transferred systems have been studied. These indicated inconsistencies regarding the presence or absence of splitting of the first reduction peak in its cyclic voltammogram (CV). The present study demonstrates the important influence of the specific anionic species present in the supporting electrolyte. Splitting may or may not take place, depending on the size and relative strength of the adsorption of specific anions contributed by the supporting electrolyte. Small, strongly adsorbing anions such as iodide produced peak splitting in the CV of C16MV monolayers; bulky but weakly adsorbing anions such as perchlorate may disrupt the ordered structure of monolayers but produce no splitting. Ancillary data provided by surface enhanced Raman spectroscopy (SERS) was consistent with the electrochemical measurements.

THERMAL ANALYSIS AND INFRARED SPECTRA OF DIALKYLAMMONIUM TETRAC HLOROCUPRATE

The thermal stability and the solid solid phase transitions in Ills compounds with n = 7-12 have been studied by DSC and TG methods. Comparision with CnZn compounds want made. The nature of three phases of CnCu has been discussed in terms of infrared spectroscopy and the assignment of the phase transitions has been given. The thermal stability of CnCu is lower than that of CnZn and presents an obvious odd even effect. All of these compounds exhibit two solid solid phase transitions in the temperature range of 248-337 K. The peak tempe nature of phase transitions changes regularly. The peak temperature or the main phase transition increases with the chain length. The total transition enthalpies and entropies increase with increasing chain length. When n <= 9, the high temperature phase exists in a partial disorder state. When n >= 10, the high temperature phase exists in a conformational disorder state. The main phase transition and the phase transition at 307.7 K of CnCu may mainly are from the change of the packing structure and the change of the partial conformational order-disorder of alkyl chain, respectively.

对-(二乙氨基)苯基锗倍半氧化物的合成及对体外培养癌细胞的作用

β-羧乙基锗倍半氧化物(Ge-132)的无毒广谱抗癌作用以及潜在的治疗艾滋病的功能~[1～3]促进了Ge-132及其衍生物合成及生物活性研究~[4～6],而对锗原子直接与苯环及其衍生物连接的有机锗倍半氧化物的研究则相对较少.我们曾报道了~[7]p-(二甲氨基)苯基锗倍半氧化物的合成、结构及对癌细胞的作用,p-(二乙氨基)苯基锗倍半氧化物的研究尚未见报道.本文采用改进的方法合成了p-(二乙氨基)苯基锗倍半氧化物(Ge-164).通过元素分析、IP、XPS和TG-DTA确定了组成和结构,观察了它对体外培养人乳腺癌细胞有丝分裂的影响.

月桂胺盐酸盐结构相变机理的红外光谱研究

月桂胺盐酸盐晶体的红外光谱研究表明,标题化合物两个结构相变的起始温度分别为327和339K。在327K以下晶体中分子以TT构象存在并以分子链相互平行的叉指状形式填充,339K以上分子以TG构象和部分GTG'构象存在并以非叉指状的六方形式填充,在327～339K之间则是一个分子构象由有序到无序、链填充由叉指状到非叉指状转变的中间过渡相。

四氯合铜酸二烷基铵相变的热分析和红外光谱

用DSC和TG研究了(n-C_nH_(2n+1)NH_3)_2CuCl_4(n=7-12)(记为C_nM)配合物的热稳定性和固-固相变。由红外光谱讨论了C_9Cu三个相的性质。发现C_nM的热稳定性呈奇偶效应;主相变峰温随链长增长而升高;相变总ΔH和ΔS也随链增长而加大;当n≤9时,高温相为部分无序相;而n≤10时,高温相为构象无序相。C_9Cu的主相变主要源自链间堆积结构变化。而在307.7K的相变主要与烃链有序-无序变化有关。

四氯合钴酸二(正十六烷基铵)层状配合物结构相变的红外光谱研究

用红外光谱和差示扫描量热法(DSC)研究了具有钙钛矿型层结构标题配合物的固-固相变。在340K处发现一个新的相变。实验证明了结构相变与烷基铵链动力学和氢键有关。在374K的主相变主要来源于烷基铵链构象的有序-无序变化,该变化可能与NH_3极性头的重定向运动偶合。在高温相在烷基铵链中产生了GTG+GTG’和GG以及临近端甲基的TG结构,因而形成了构象完全无序态。