Grajewski Jakub, Mądry Tomasz, Kwit Marcin, Warżajtis Beata, Rychlewska Urszula, Gawroński Jacek
Department of Chemistry, Adam Mickiewicz University, Umultowska 89B, 61-614, Poznań, Poland.
Chemphyschem. 2017 Aug 18;18(16):2197-2207. doi: 10.1002/cphc.201700332. Epub 2017 Jun 20.
The benzhydryl (diphenylmethyl) group is a molecular propeller that can act as a chirality reporter if it is introduced nearby a stereogenic center by making an ether bond. The hydrophobic character of the benzhydryl group allows transformation of insoluble natural tartaric acid derivatives into soluble entities in a nonpolar environment. Electronic circular dichroism spectra, recorded within the short-wavelength region of the phenyl B transitions (190-200 nm) shows strong bisignate Cotton effects. The signs and magnitudes of these Cotton effects are a function of absolute configuration and conformation of the molecule and do not primarily arise from exciton coupling of chiral benzhydryl chromophores. In crystals, the main-chain conformation is stabilized by intramolecular hydrogen bonds and CH-CO dipolar interactions. The number of the donor NH groups has a pronounced effect on the preferred conformations and inclusion properties of benzhydryl-(R,R)-tartaric acid diamides. Evidence is shown for the solvent dependency of the conformations of NH amides of tartaric acid diphenylmethyl ethers.
二苯甲基（二苯基甲基）基团是一种分子螺旋桨，如果通过形成醚键将其引入到立体中心附近，它可以作为手性报告基团。二苯甲基基团的疏水特性使得不溶性天然酒石酸衍生物在非极性环境中转化为可溶实体。在苯基B跃迁的短波长区域（190 - 200 nm）记录的电子圆二色光谱显示出强烈的双符号科顿效应。这些科顿效应的符号和大小是分子绝对构型和构象的函数，并非主要源于手性二苯甲基发色团的激子耦合。在晶体中，主链构象通过分子内氢键和CH - CO偶极相互作用得以稳定。供体NH基团的数量对二苯甲基 - (R,R) - 酒石酸二酰胺的优选构象和包合性质有显著影响。有证据表明酒石酸二苯甲基醚的NH酰胺构象存在溶剂依赖性。
