Crystal structure determination of two pyridine derivatives: 4-[(E)-2-(4-meth-oxy-phen-yl)ethen-yl]-1-methyl-pyridin-1-ium hexa-fluoro-λ⁶-phosphane and 4-{(E)-2-[4-(di-methyl-amino)-phen-yl]ethen-yl}-1-phenyl-1λ⁵-pyridin-1-ylium hexa-fluoro-λ⁶-phosphane

The title mol-ecular salts, C₁₆H₁₆NO⁺·PF₆ ^-, (I), and C₂₁H₂₁N₂ ⁺·PF₆ ^-, (II), are pyridine derivatives. In compound (I), the cation comprises a methyl N-substituted pyridine ring and a meth-oxy-substituted benzene ring connected by a C=C double bond. The F atoms of the PF₆ ^- anion are disordered over two sets of sites with refined occupancy factors of 0.614 (7):0.386 (7). In compound (II), the cation comprises a pyridine ring attached to unsubstituted phenyl ring and a di-methyl-aniline ring, which are connected by a C=C double bond. The anion is PF₆ ^-. In both salts, the cation adopts an E configuration with respect to the C=C bond. The pyridine ring makes a dihedral angle of 9.86 (12)° with the meth-oxy-substituted benzene ring in compound (I) and 11.2 (3)° with the di-methyl-amine-substituted benzene ring in compound (II). In compound (I), the crystal packing is stabilized by weak C-H⋯F inter-molecular inter-actions which result in R ⁴ ₃(14) ring motifs, forming mol-ecular sheets running parallel to (03). These are further stabilized by weak P-F⋯π interactions. In compound (II), the crystal packing is stabilized by C-H⋯F inter-actions, which result in R ⁶ ₆(40) ring motifs, forming mol-ecular sheets running parallel to (101) and these are further connected by π-π inter-actions.