An members of the methylated tropylium perchlorates have been synthesized and their properties (UV absorptions, 1H NMRspectra, and charge-transfer spectra with pyrene) determined. The methylated tropylium ions other than the hexa- and hepta-methyl homologues have been prepared by abstracting a hydride ion with trityl perchlorate from the corresponding methylated tropilidenes. The preparation of the
已合成了一部分甲基化的高氯酸对苯二铵盐及其性质(紫外线吸收,11 H NMR光谱,和带有pyr的电荷转移光谱)被确定。除了六甲基和七甲基同系物外,甲基化的tropylium离子是通过从相应的甲基化的对苯二甲酰亚胺中提取高碘酸三苯酯的氢化物离子而制得的。通过使用五氯化磷作为氢化物吸收剂,已经完成了六甲基和七甲基甲基trop离子的制备。通过以下三种已知途径之一制备甲基化对苯二甲腈,即甲基化苯与重氮甲烷(途径1)或重氮乙酸乙酯(途径2)的环扩环,以及环丙烯或甲基环丙烯与甲基化噻吩1,1-的环加成反应。二氧化硫,并排除二氧化硫(路线3)。甲基1已经部分地借助Me 13 C NMR化学位移数据指定了H NMR化学位移值,该数据是在连续的环碳(3a,4a,5a,6和7)上包含Me基的对苯二甲基离子。pyr与with的离子的电荷转移带的跃迁能随Me基团数量的增加而增加,表明对yl离子甲基化程度越高,离子越稳定。
The one-electron reduction of carbonium ions. Part 14. Effect of successive introduction of methyl substituents on the reducibility of tropylium ion in chromium(II) ion and cathodic reductions
The second-order rate constants (k2) of one-electron reduction with CrII ion of methylated tropylium ions [C7H7 –n(CH3)n+ClO4–, n= 0–7] were determined in 10% hydrochloric acid at 25.0°C. Reduction peak potentials determined by means of triangular wave cyclic voltammetry and charge transfer energies with pyrene were compared with the rates of CrII ion reduction in terms of the effect of methyl substituents
Heptamethyltropylium perchlorate has been synthesized via the reaction of 1,2,3,4,5,6,7-heptamethyltropilidene with phosphoruspentachloride and subsequent treatment with perchloric acid. The advantage of phosphoruspentachloride over triphenylcarbenium ion as a hydride-abstraction reagent is discussed.