Intermolecular photoinduced electron-transfer processes between C60 and aniline derivatives in benzonitrile

The quenching behavior of the triplets of C₆₀ by various aniline derivatives (1a-d and 2a-e) was investigated by means of laser flash photolysis in benzonitrile at 293 K. Electron transfer process was proposed to be the main mechanism because of the direct detection of radical ions of aniline derivatives and C₆₀ in time-resolved transient absorption spectra. The quenching rate constants (k_q) of by different substrates determined at 740 nm approach or reach the diffusion-controlled limit. DFT method was employed to calculate the unknown oxidation potentials of substrates in solution. With these E_ox values, free energy changes (ΔG) were obtained through Rehm-Weller equation. Dependence of observed quenching rate constants on the free energy changes further indicates the photoinduced reactions between ³C₆₀^* and substrates proceed through an electron transfer mechanism. Obtained k_q values for the aniline derivatives are impacted obviously by ground-state configurations and the kinds substituents quantified by Hammett σ constant. Good correlation between log k_q and σ values conforms to the empirical Hammett equation. A more negative ρ value (−3.356) was gained for anilines (2a-e) than that of N,N-dimethylanilines (1a-d) (−1.382), which suggests a more susceptible reactivity for the former substrates. Charge density distribution of reaction center “N” originated from quantum calculation supports this suggestion. In addition, a relationship between quenching rate constants and solvent viscosity was gained from C₆₀/dimethyl-p-toluidine system in altered mixtures of acetonitrile and toluene.     

气相色谱-质谱法测定汽油中8种醚类和苯胺类添加剂

采用气相色谱-质谱法同时测定汽油8种醚类和苯胺类化合物。采用强极性离子液体色谱柱(SLB-1L 111毛细管色谱柱)分离样品,质谱中选择电喷雾离子源-选择离子监测模式,以苯乙酮为内标物进行定量分析。8种化合物的质量分数在10~10 000 mg·kg-1范围内与其峰面积呈线性关系,检出限(3S/N)在0.2~2.0 mg·kg-1之间。加标回收率在91.2%~111%之间,测定值的相对标准偏差(n=7)在0.18%~3.0%之间。     

苯酚苯胺共聚物在304不锈钢电极表面的电化学合成及成膜微观结构分析

苯酚和苯胺在304不锈钢阳极表面实现了电化学共聚,反应在中性水溶液中进行,电解质为硫酸钠. 比较不同苯酚苯胺浓度下共聚成膜耐点蚀能力,当苯酚为0.09 mol/L和苯胺为0.01 mol/L时最佳.红外光谱分析证实苯胺结构出现在苯酚苯胺的共聚物中,且共聚物膜比聚苯酚膜含有更多支链. 利用苯酚苯胺共聚物膜在四氢呋喃中的部分溶解性,使用扫描电子显微镜分析四氢呋喃清洗前后的成膜,观察到网状聚苯胺结构. 将共聚物膜与聚苯酚膜微观结构进行推测和比较,解释在电聚合反应中适量加入苯胺能提升成膜防腐能力原因.     

几种聚合物改性硅胶对苯胺的吸附性能研究

研究了聚乙烯基吡啶改性硅胶(PVP/SiO2)、聚苯乙烯改性硅胶(PS/SiO2)、胺化聚苯乙烯改性硅胶(PS-NH2/SiO2)等3种有机-无机复合材料吸附剂对苯胺的吸附行为。吸附动力学研究表明,3种吸附剂对苯胺的吸附均符合准二级动力学方程。对其粒内扩散模型模拟的结果表明,在3种吸附过程中液膜扩散为主要速率控制步骤。用Langmuir等温吸附方程式和Freundlich等温吸附方程式对其吸附等温线进行了拟合,结果表明,PVP/SiO2、PS/SiO2对苯胺的吸附符合Freundlich等温吸附方程式。     

One step synthesis of azo compounds from nitroaromatics and anilines

A general and efficient method for synthesis of both symmetric and asymmetric aromatic azo compounds in one single step has been developed. The nitro compounds were reduced and the substituted anilines were oxidized by each other without any metal in the base condition. Various azo compounds with halogen, methyl and methoxy functional group were obtained by using available, cheap nitro compounds and substituted anilines. In addition, the electronic effect and substituent effect of the compounds have been discussed.     

Zinc triflate-catalyzed intermolecular hydroamination of vinylarenes and anilines: scopes and limitations

Intermolecular hydroamination of vinylarenes and anilines was studied using zinc triflate as catalyst. NMR experiments supported a Lewis acid activation of the CC double bond. Electronic/steric effect study indicated that Lewis acidity of the catalyst as well as the coordination property of the amine were the governing factors for successful hydroamination of the substrates. More nucleophilic amine would bind more tightly to the central metal, leading to an unproductive coordination. Approach of bulky amine to CC bond would be hindered, and an alternative electrophilic substitution on benzene ring of the amine would become the major reaction. Electrophilic substitution would become predominant when strong electron-donating group is presented on aniline benzene ring.     

Electrochemical properties of 3,5-diphenylaniline units encapsulated within a crown ether. Effects of the macrocycle’s aromatic functionality and ring size

This Letter describes a series of [2]rotaxanes featuring a 3,5-diphenylaniline terminus in their dumbbell-shaped component and crown ethers as the macrocyclic component, prepared through imine formation and hydrogen bond—guided self-assembly. Electrochemical studies of these [2]rotaxanes revealed that the oxidation potential of the aniline moiety when positioned within the cavity of a crown ether was shifted negatively relative to that of the corresponding dumbbell-shaped compound, and that a crown ether possessing a small cavity and a large number of aromatic rings had a more negative effect on the oxidation potential of the aniline moiety than did a large-cavity crown ether featuring no aromatic rings. UV experiments showed that absorption band of the rotaxanes bearing small crowns shifted to longer wavelengths as compared to those of the rotaxanes having large crowns.     

Coordination of bidentate aniline derivatives to the fac-[Re(CO)3] core

A series of rhenium(I) tricarbonyl complexes, containing bidentate derivatives of aniline, was synthesized and structurally characterized. With 1,2-diaminobenzene (Hpda) the ‘2+1’ complex salt fac-[Re(CO)₃(Hpda)₂]Br was isolated. The neutral complex [Re(CO)₃(Hapa)Br] was formed with 2-aminodiphenylamine (Hapa) as ligand. 2-Aminophenol (Hopa) also produced the neutral ‘2+1’ complex [Re(CO)₃(opa)₂(Hopa)], but with 2-mercaptophenol (Hspo) the bridged dimer [Re₂(CO)₇(spo)₂] was found. In the complex [Re(CO)₃(Htpn)Br] (Htpn = N′-{(2-methylthio)benzylidene}benzene-1,2-diamine) the potentially tridentate ligand Htpn is coordinated via the methylthio sulfur and imino nitrogen atoms only, with a free amino group.     

Thermo acoustic and spectral investigations of charge transfer interaction between aromatic amine and ketones

Ultrasonic velocity (u), density (ρ) and coefficient of viscosity (η) were measured for ternary mixtures containing aniline (ANI) as common component and acetophenone (ACP), 4-chloroactophenone (ClACP) and 4-methylacetophenone (MACP) as other components in n-hexane medium in the concentration range 0.025-0.2 M. The measurements were made at four different temperatures, namely, 293, 298, 303 and 308 K and at atmospheric pressure. The experimental results have been used to calculate various acoustical parameters and excess parameters. The trend in these parameters with concentration establishes that (i) strong intermolecular interactions exist in these mixtures and (ii) formation of charge transfer complexes through hydrogen bonding between primary amine and aromatic ketones. The formation of complexes has also been confirmed by optical spectroscopy at 303 K. The formation constants of the charge transfer complexes determined using Benesi-Hildebrand equation (spectroscopic method) are comparable with those obtained using Kannappan equation (ultrasonic method). It is observed that the stability of the complexes is influenced by the structure of the component molecules. In order to assess the thermodynamic stability of the complexes, free energy of formation (ΔG), enthalpy of formation (ΔH) and entropy changes (ΔS) are computed.     

闭路循环动态针捕集-气相色谱法分析地下水中的硝基苯和苯胺

动态针捕集(Needle trap,NT)是一种集采样、提取、浓缩、进样于一体的免溶剂分析技术,适于痕量有机目标组分的采样分析.本研究通过对比6种采样技术,研究了基于超声的闭路循环动态顶空-NT分析地下水中的硝基苯及苯胺的方法,确定了NT对地下水目标物顶空采样的最佳条件;通过对比GC普通分流/不分流进样口和一种多模式OPTIC2进样口,优化NT的解吸条件,得出的OPTIC2进样口对目标物响应值高且峰形尖锐.填充一层吸附剂的NT对目标物的残留低于0.79％,苯胺的检出限为2.9～3.7μg/L,硝基苯的检出限为0.7～1.9 μg/L.苯胺和硝基苯的回收率在83％～113％之间.