Self-association in {2-[3,4-alkylenedioxy-5-(3-pyridyl)]-thienyl}alkanols: an NMR, IR, and single-crystal X-ray study
作者:John S. Lomas、Christine Cordier、Alain Adenier、François Maurel、Jacqueline Vaissermann
DOI:10.1002/poc.1166
日期:2007.6
self-associate both in the solid state and in solution. Single-crystal X-ray diffraction study of the 3,4-ethylenedioxythiophene (EDOT) derivative shows that it exists as a centrosymmetric head-to-tail, syn dimer in the solid state. The IR spectra of the solids display only a broad OH absorption around 3300 cm−1, corresponding to a hydrogen-bonded species. 1H Nuclear Overhauser Effect Spectroscopy (NOESY) NMR
syn -2,2,4,4-四甲基-3- 2- [3,4-亚烷基二氧基-5-(3-吡啶基)]噻吩基}戊三-3-醇在固态和溶液中均自缔合。3,4-乙撑二氧噻吩(EDOT)衍生物的单晶X射线衍射研究表明,它以中心对称的头对尾顺式二聚体形式存在。固体的红外光谱仅在3300 cm -1附近显示宽的OH吸收,相当于氢键结合的物质。1 H核磁共振极化效应光谱(NOESY)的苯NMR实验揭示之间的相互作用叔-丁基和吡啶基的H2和H6质子。基于(i)顺式/反式比率和(ii)顺式旋转异构体的OH质子位移的浓度依赖性,已采用两种方法通过NMR滴定法确定EDOT衍生物的缔合常数。从298 K到323 K(在298 K分别为3.6和3.9 M -1)获得了合理一致的结果。从3,4-亚甲基二氧噻吩(MDOT)衍生物的顺式OH质子位移变化中获得了相似的值。所述的浓度有关的变化反在后者的OH质子移表明抗异构体以开放的,