Chemical Engineering and Materials Science, Michigan State University, East Lansing, MI, United States.
Magn Reson Chem. 2013 Aug;51(8):490-6. doi: 10.1002/mrc.3962. Epub 2013 May 27.
Cis and trans isomers of a series of double-decker silsesquioxanes (DDSQ) were characterized by two-dimensional NMR techniques. The (1)H NMR spectra of these species have not previously been assigned to a degree that allows for quantification. Thus, (1)H-(29) Si HMBC correlations were applied to facilitate (1)H spectral assignment and also to confirm previous (29)Si assignments for this class of silsesquioxanes. With the ability to identify all the pertinent resonances of the (1)H NMR spectrum, (29)Si NMR is no longer required for quantification and required only for characterization. This not only saves time and material but also provides a more accurate quantification, thus allowing for the ratio of cis and trans isomers present in each compound to be determined. A more accurate measure of the cis/trans ratio enables the investigation of its influence on the physical and chemical properties of DDSQ nanostructured materials.
一系列双层笼型倍半硅氧烷（DDSQ）的顺式和反式异构体通过二维 NMR 技术进行了表征。这些物质的（1）H NMR 谱以前尚未进行到可以定量的程度。因此，应用（1）H-（29）Si HMBC 相关来促进（1）H 谱的分配，并确认该类笼型倍半硅氧烷的先前（29）Si 分配。通过能够识别（1）H NMR 谱的所有相关共振，可以不再需要（29）Si NMR 进行定量，而仅用于表征。这不仅节省了时间和材料，而且还提供了更准确的定量，从而可以确定每个化合物中顺式和反式异构体的比例。对顺/反比的更准确测量可以研究其对 DDSQ 纳米结构材料的物理和化学性质的影响。
