He Jin-Hao, Cheng Wei-Wei, Zhang Ai-Qing, Qin Si-Yong
Hubei Engineering Technology Research Centre of Energy Polymer Materials, South-Central Minzu University, Wuhan 430074, P. R. China.
Hubei Engineering Technology Research Centre of Energy Polymer Materials, Key Laboratory of Analytical Chemistry of the State Ethnic Affairs Commission, South-Central Minzu University, Wuhan 430074, P. R. China.
Anal Chem. 2024 Jul 23;96(29):11881-11889. doi: 10.1021/acs.analchem.4c01558. Epub 2024 Jul 8.
Both solitary and tandem applications of residual chemical shift anisotropy (RCSA) and residual dipolar coupling (RDC) show great potential for the structural and configurational determination of organic molecules. A critical component of both RDC and RCSA methodologies is the alignment medium, whose availability is limited, especially for RCSA measurement. Moreover, reported RDC and RCSA acquisitions mainly rely on two experiments conducted under two different conditions, which are relatively time-consuming and easily cause experimental errors. Herein, a biphasic supramolecular lyotropic liquid crystalline (LLC) system was developed through the self-assembly of CH-CONH-VK-CONH, which could act as an alignment medium for not only RDC but also RCSA extraction in DMSO-. Notably, the RCSA extraction was easily achieved via one-shot measurement from a single one-dimensional C NMR experiment, with no need for special instruments, devices, and correction. Relying on the biphasic LLC medium, meanwhile, RDC data were simply extracted from a single F1-coupled HSQC experiment, different from the standard protocol that requires two spectral acquisitions corresponding to the isotropic and anisotropic conditions. Collectively, the biphasic LLC medium is applicable for tandem RCSA and RDC measurements in one single sample, advancing the stereochemical elucidation of molecules of interest.
残余化学位移各向异性(RCSA)和残余偶极耦合(RDC)的单独及串联应用在有机分子的结构和构型测定方面均显示出巨大潜力。RDC和RCSA方法的一个关键组成部分是取向介质,其可用性有限,尤其是对于RCSA测量。此外,已报道的RDC和RCSA采集主要依赖于在两种不同条件下进行的两个实验,这相对耗时且容易导致实验误差。在此,通过CH-CONH-VK-CONH的自组装开发了一种双相超分子溶致液晶(LLC)体系,其不仅可以作为RDC的取向介质,还可以用于在DMSO-中提取RCSA。值得注意的是,通过单次一维碳核磁共振实验的单次测量即可轻松实现RCSA提取,无需特殊仪器、设备和校正。同时,依托双相LLC介质,只需从单个F1耦合的HSQC实验中简单提取RDC数据,这与需要对应各向同性和各向异性条件进行两次光谱采集的标准方案不同。总体而言,双相LLC介质适用于在单个样品中进行串联RCSA和RDC测量,推动了目标分子的立体化学阐释。