NMR spectral simplification with imidazolium ionic liquid-coated silica nanoparticles

Abstract

NMR spectral simplification is a powerful strategy for facilitating the analysis and structural characterization of complex mixtures. In this work, we present a nanoparticle-assisted protocol that employs positively charged imidazolium ionic liquid-coated silica nanoparticles (1) to selectively interact with analytes. π-π interactions, electrostatic attractions, and hydrogen-bonding between the nanoparticles and target molecules extend the rotational correlation time, thereby accelerating relaxation processes. As a result, NMR signals from aromatic and negatively charged species undergo pronounced attenuation or even complete disappearance. In contrast, signals from positively charged analytes or compounds lacking π-bond systems remain largely unaffected. This selective suppression of resonances enables effective spectral simplification and highlights the potential of nanoparticle-based editing approaches for practical applications in the analysis and structural determination of complex mixtures.