Nonpolar graphene oxide (GO-NP): a heterogeneous liquid crystalline alignment medium for anisotropic NMR in nonpolar organic solvents

Abstract

This study reports the development of a novel nonpolar variant of graphene oxide (GO-NP) as a heterogeneous NMR alignment medium for less polar organic solvents such as CDCl₃. GO-NP was obtained through a stepwise derivatisation of polar GO with C₁₀ and C₁₈ alkyl amines, incrementally enhancing its dispersive character. The resulting doubly functionalised GO-NP exhibits liquid crystalline properties in CDCl₃, enabling anisotropic NMR characterisation of small molecules. This represents the first GO-based system effectively suitable as a heterogeneous, dispersive alignment medium for nonpolar solvents, facilitating RDC investigations with background-free NMR spectra and complete analyte recovery.