Deuterium and carbon-13 NMR study of a banana mesogen: Molecular structure and order
Deuterium and carbon-13 NMR study of a banana mesogen: Molecular structure and order
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DOI：
10.1021/jp0498264
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发表时间：
2004-06-10
影响因子：
3.3
通讯作者：
Veracini, CA
中科院分区：
文献类型：
--
作者：
Dong, RY;Fodor-Csorba, K;Veracini, CA
本文用H-2和C-13 NMR研究了香蕉液晶分子4-氯-1，3-亚苯基双{4，4 ′-（11-十一烯氧基）苯甲酰氧基}苯甲酸酯在反相的取向顺序和分子结构。详细讨论了整个分子核或选择性氘代片段的取向序参数，以及分子刚性核的几何特征。特别是，估计每个侧翼的芳环的帕拉轴和长分子轴之间的角度θ 1。采用B3 LYP密度泛函方法对中心五个芳环组成的刚性核心进行量子化学计算，支持由核磁共振结果推导出的分子结构。这项研究表明，如何重要的是H-2和C-13 NMR之间的比较，以更好地了解真实的结构的香蕉形化合物在其中间相，并进一步揭示了有关香蕉分子的手性或非手性的悬而未决的问题。
The orientational order and the molecular structure of the banana mesogen 4-chloro-1,3-phenylene bis{4,4'-(11-undecenyloxy)benzoyloxy}benzoate have been studied in its nematic phase by means of H-2 and C-13 NMR. A detailed discussion of orientational order parameters for either the entire molecular core or the selectively deuterated fragments, and geometrical features concerning the rigid core of the molecule is given. In particular, the angles thetai between the para axis of the aromatic ring and the long molecular axis for each lateral wing are estimated. Quantum chemical calculations on the rigid core made by the central five aromatic rings, employing the B3LYP density functional method, support the molecular structure derived from the NMR results. This study shows how important is the comparison between H-2 and C-13 NMR to better understand the real structure of banana-shaped compounds in their mesophases and further sheds light on the open question about chirality or achirality of banana molecules.