The crystal structures of phenylpropylpyridine-N-oxide and N-methyl-phenylpropylpyridinium iodide are compared, revealing that hydrogen bonding with the solvent molecule plays an important role in the N-oxide compound, whilst electrostatic interactions are predominant in controlling the solid-state orientation of the N-methylated compound. Fluorescence spectroscopy and NOESY indicate that in contrast to the previously reported pyridinium iodide, the N-oxide is not subject to intramolecular -stacking, as judged by excimer emission and a lack of corresponding cross peaks, respectively.
Richter, I., Warren, M. R., Minari, J., Elfeky, S. A., Chen, W., Mahon, M. F., Raithby, P., James, T. D., Sakurai, K., Teat, S. J., Bull, S. D., & Fossey, J. S. (2009). Solid-State Structures and Solution Analyses of a Phenylpropylpyridine N-Oxide and an N-Methyl Phenylpropylpyridine. Chemistry - An Asian Journal, 4(1), 194-198. https://doi.org/10.1002/asia.200800255