通过高分辨率的1H和13C固态NMR光谱学识别天然同位素丰度的瓜诺辛自我组合
Amy L Webber1, Stefano Masiero, Silvia Pieraccini
1Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom.
Journal of the American Chemical Society
|November 1, 2011
概括
固态NMR可以识别瓜诺衍生物的自我组装结构,如带和四重奏. 这种方法可以区分NH···N和NH··O的键,有助于在没有晶体的情况下进行结构分析.
科学领域:
- 固态核磁共振 (NMR) 光谱学 固态核磁共振 (NMR) 光谱学
- 超分子化学 超分子化学
- 瓜诺辛衍生物自组合器
背景情况:
- 瓜诺衍生物可以形成自我组装的结构,但在没有单晶的情况下确定这些结构是具有挑战性的.
- 之前的研究利用同位素标记和衍射进行结构阐明.
- 区分不同的自组装图案 (例如,带状与四重奏状) 需要敏感的分析方法.
研究的目的:
- 开发和应用非同位素标记的固态NMR方法来识别瓜诺衍生物的自组装结构.
- 根据光谱特征来区分带状和四重奏状的自组装.
- 为了将NMR发现与已知的结构数据和计算预测相关联.
主要方法:
- 使用质子双量子 (DQ) 联合旋转和多脉冲光谱学 (CRAMPS) 固态NMR相关性光谱识别了质子-质子相邻.
- 分析 (1) H 化学转移,特别是 NH 和 NH (2) 共振.
- 测量器包括投射器增强波 (GIPAW) 化学转移计算用于光谱分配.
- (14) 在快速魔法角旋转 (MAS) 下使用N-(1) H相关性光谱.
主要成果:
- 在未标记的瓜诺辛衍生物中观察到明显的光谱指纹,用于带状和四重奏状的自我组装.
- 带状结构中NH的较高 (1) H化学转移 (13-15 ppm) 表明NH··O结,而四重奏状结构 (NH···N) 的10-11 ppm.
- 逆顺序的NH(2) (1)H化学转移区分两个组件类型.
- 使用GIPAW计算和 (14) N-(1) H相关性光谱证实了分配,揭示了更长距离的近距离.
结论:
- 固态NMR,特别是DQ CRAMPS,对于识别无同位素标记的瓜诺辛衍生物的自我组装结构是有效的.
- 核磁共振的光谱特征,包括NH化学转移和NH(2) 共振排序,可靠地区分了带状和四重奏状的排列.
- 这项研究提供了一个强大的工具,用于在单晶无法使用的情况下,在具有挑战性的情况下确定超分子结构.
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