Cirić-Marjanović Gordana, Trchová Miroslava, Konyushenko Elena N, Holler Petr, Stejskal Jaroslav
Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11158 Belgrade, Serbia.
J Phys Chem B. 2008 Jun 12;112(23):6976-87. doi: 10.1021/jp710963e. Epub 2008 May 20.
The course of oxidation of 4-aminodiphenylamine with ammonium peroxydisulfate in an acidic aqueous ethanol solution as well as the properties of the oxidation products were compared with those of 2-aminodiphenylamine. Semiconducting oligomers of 4-aminodiphenylamine and nonconducting oligomers of 2-aminodiphenylamine of weight-average molecular weights 3700 and 1900, respectively, were prepared by using an oxidant to monomer molar ratio of 1.25. When this ratio was changed from 0.5 to 2.5, the highest conductivity of oxidation products of 4-aminodiphenylamine, 2.5 x 10 (-4) S cm (-1), was reached at the molar ratio [oxidant]/[monomer] = 1.5. The mechanism of the oxidative polymerization of aminodiphenylamines has been theoretically studied by the AM1 and MNDO-PM3 semiempirical quantum chemical methods combined with the MM2 molecular mechanics force-field method and conductor-like screening model of solvation. Molecular orbital calculations revealed the prevalence of N prim-C10 coupling reaction of 4-aminodiphenylamine, while N prim-C5 is the main coupling mode between 2-aminodiphenylamine units. FTIR and Raman spectroscopic studies confirm the prevalent formation of linear N prim-C10 coupled oligomers of 4-aminodiphenylamine and suggest branching and formation of phenazine structural units in the oligomers of 2-aminodiphenylamine. The results are discussed with respect to the oxidation of aniline with ammonium peroxydisulfate, leading to polyaniline, in which 4-aminodiphenylamine is the major dimer and 2-aminodiphenylamine is the most important dimeric intermediate byproduct.
在酸性乙醇水溶液中，将4-氨基二苯胺用过硫酸铵氧化的过程以及氧化产物的性质与2-氨基二苯胺的进行了比较。分别使用氧化剂与单体的摩尔比为1.25，制备了重均分子量分别为3700的4-氨基二苯胺半导体低聚物和重均分子量为1900的2-氨基二苯胺非导电低聚物。当该比例从0.5变为2.5时，4-氨基二苯胺氧化产物的最高电导率为2.5×10⁻⁴ S cm⁻¹，在[氧化剂]/[单体] = 1.5的摩尔比下达到。采用AM1和MNDO-PM3半经验量子化学方法，结合MM2分子力学力场方法和导体类溶剂化筛选模型，对氨基二苯胺的氧化聚合机理进行了理论研究。分子轨道计算表明，4-氨基二苯胺的N'-C10偶联反应占主导，而N'-C5是2-氨基二苯胺单元之间的主要偶联模式。傅里叶变换红外光谱（FTIR）和拉曼光谱研究证实了4-氨基二苯胺线性N'-C10偶联低聚物的普遍形成，并表明2-氨基二苯胺低聚物中存在支化和吩嗪结构单元的形成。结合苯胺用过硫酸铵氧化生成聚苯胺的情况对结果进行了讨论，其中4-氨基二苯胺是主要二聚体，2-氨基二苯胺是最重要的二聚体中间副产物。
