Associative combination of lone pair–π, π–π and anion–π interactions observed in a ternary system comprising Mg(II)-malonate–2-aminopyridine–hexafluoridophosphate

One Mg(II) malonate complex with protonated 2-aminopyridine and hexafluoridophosphate as counterions, (C5H7N2)4[Mg(C3H2O4)2(H2O)2](PF6)2 (1) [C5H7N2 = protonated 2-aminopyridine, C3H4O4 = malonic acid] has been synthesized from purely aqueous media just by mixing the reactants in their stoichiometric proportion and its crystal structure has been determined by single-crystal X-ray diffraction. The role of weak forces like lone pair⋯⋯π and anion⋯⋯π interactions in influencing the self-assembly process appears to be of importance. A rare combination of lone pair⋯⋯π and anion⋯⋯π interactions in 1, of the type lone pair⋯⋯π/π⋯⋯π/π⋯⋯anion, is observed, and this unusual supramolecular network is fully described here.

Graphical abstractCombination of various weak forces of the type lone pair⋯⋯π/π⋯⋯π/π⋯⋯anion has been observed in the solid state structure of (C5H7N2)4[Mg(C3H2O4)2(H2O)2](PF6)2 [C5H7N2 = protonated 2-aminopyridine, C3H4O4 = malonic acid].Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Mg(II)-malonate–2-aminopyridine–hexafluoridophosphate system has been structurally analyzed. ► The compound has been synthesized from purely aqueous media. ► A rare combination of lone pair-π/π–π/π-anion type of interaction is observed.