Exploring the Molecular Structure of Imidazolium-Silica-Based Nanoparticle Networks by Combining Solid-State NMR Spectroscopy and First-Principles Calculations

• Published in: Chemistry : a European journal Vol. 20; no. 46; pp. 15188 - 15196
• Main Authors: Neouze, Marie-Alexandra, Kronstein, Martin, Litschauer, Marco, Puchberger, Michael, Coelho, Cristina, Bonhomme, Christian, Gervais, Christel, Tielens, Frederik
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 10.11.2014; WILEY‐VCH Verlag; Wiley Subscription Services, Inc; Wiley-VCH Verlag
• Subjects: Chemical Sciences; Chemistry; Density; density functional calculations; Inns; luminescence; Material chemistry; Mathematical models; Molecular structure; Nanoparticles; Nanostructure; Networks; NMR; NMR spectroscopy; Nuclear magnetic resonance; Principles; Sourcing; surface chemistry; density functional calculations; luminescence; nanoparticles; surface chemistry; NMR spectroscopy
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201403730

A DFT‐based molecular model for imidazolium–silica‐based nanoparticle networks (INNs) is presented. The INNs were synthesized and characterized by using small‐angle X‐ray scattering (SAXS), NMR spectroscopy, and theoretical ab initio calculations. 11B and 31P HETCOR CP MAS experiments were recorded. Calculated 19F NMR spectroscopy results, combined with the calculated anion–imidazolium (IM) distances, predicted the IM chain density in the INN, which was also confirmed from thermogravimetric analysis/mass spectrometry results. The presence of water molecules trapped between the nanoparticles is also suggested. First considerations on possible π–π stacking between the IM rings are presented. The predicted electronic properties confirm the photoluminescence emissions in the correct spectral domain. Sourcing luminescence: Imidazolium–silica‐based nanoparticle networks (INNs) have been synthesized and characterized (see picture). A molecular model for the imidazolium–silica network is presented and described. The presence of water near the silica surface and its influence on the position of the counteranions in the INN has been shown.