Crystal structures of the hexa-fluorido-phosphate salts of the isomeric 2-, 3- and 4-cyano-1-methyl-pyridinium cations and determination of solid-state inter-action energies.

The synthesis and crystal structures of the isomeric mol-ecular salts 2-, 3- and 4-cyano-1-methyl-pyridinium hexa-fluorido-phosphate, CHN·PF, are reported. In 2-cyano-1-methyl-pyridinium hexa-fluorido-phosphate, C-H⋯F hydrogen bonds form chains extending along the -axis direction, which are associated through C-H⋯F hydrogen bonds and P-F⋯π(ring) inter-actions into stepped layers. For 3-cyano-1-methyl-pyridinium hexa-fluorido-phosphate, corrugated sheets parallel to [001] are generated by C-H⋯F hydrogen bonds and P-F⋯π(ring) inter-actions.