Identification and quantification of cis and trans isomers in aminophenyl double‐decker silsesquioxanes using 1 H– 29 Si gHMBC NMR

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. Copyright © 2013 John Wiley & Sons, Ltd.