Inorganic-organic hybrid materials based on the intercalation of radical cations: 2-(4-N-methylpyridinium)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-oxyl-3-N-oxide in fluoromica clay

Abstract

Abstract A systematic structural study on the intercalation of the radical cation 2-(4-N-methylpyridinium)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-oxyl-3-N-oxide (p-MPYNN) into a synthetic fluoromica clay named Somasif® ME 100, Na2x Mg3.0−x Si4O10(F y OH1−y )2 (x = 0.33, y = 0.98), has been carried out. The guest–host interactions in these intercalation compounds have been characterized by X-ray powder diffraction and solid-state NMR of the constituent nuclei (23Na, 19F, 27Al and 29Si) of the Somasif lattice. The intercalation process can be quantitatively monitored using 23Na MAS-NMR. As a function of radical ion loading, different kinds of stacking arrangements can be realized, which modify the intermolecular interactions between the electron spins of the guest species, as probed by electron spin resonance (EPR) and 1H solid state nuclear magnetic resonance (NMR). The results are discussed in relation to previous literature data on similar systems.