Xia Yiyin, Koenis Mark A J, Collados Juan F, Ortiz Pablo, Harutyunyan Syuzanna R, Visscher Lucas, Buma Wybren J, Nicu Valentin P
Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.
Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands.
Chemphyschem. 2018 Mar 5;19(5):561-565. doi: 10.1002/cphc.201701335. Epub 2018 Jan 29.
Experimental and theoretical studies of the vibrational circular dichroism (VCD) spectrum of 3-methyl-1-(methyldiphenlsilyl)-1-phenylbutan-1-ol, whose absolute configuration is key to elucidating the Brook rearrangement of tertiary benzylic α-hydroxylsilanes, are presented. It is found that the entire OH-bending region in this spectrum-a region that provides important marker bands-cannot be reproduced at all by standard theoretical approaches even though other regions are well described. Using a novel approach to disentangle contributions to the rotational strength of these bands, internal coordinates are identified that critically influence the appearance of this part of the spectrum. We show that the agreement between experiment and theory is greatly improved when structural dynamics along these coordinates are explicitly taken into account. The general applicability of the approach underlines its usefulness for structurally flexible chiral systems, a situation that is more the rule rather than the exception.
本文给出了3-甲基-1-(甲基二苯基硅基)-1-苯基丁-1-醇振动圆二色性（VCD）光谱的实验和理论研究，该化合物的绝对构型对于阐明叔苄基α-羟基硅烷的布鲁克重排至关重要。结果发现，尽管该光谱的其他区域能够被标准理论方法很好地描述，但其中整个OH弯曲区域（该区域提供重要的标记带）根本无法被标准理论方法重现。通过一种新颖的方法来解析这些谱带的转动强度贡献，确定了对该光谱这一部分外观有关键影响的内坐标。我们表明，当明确考虑沿这些坐标的结构动力学时，实验与理论之间的一致性得到了极大改善。该方法的普遍适用性突显了其对于结构灵活的手性体系的有用性，而这种情况在更多时候是普遍存在而非例外。
