Crystallinity-dependence of ionic conductivity in the ion pairs of a multi-interactive anion

Abstract

Ammonium and sodium salts (ion pairs) of a multi-interactive tri(4-pyridyl)hexaazaphenalenyl anion (TPHAP⁻) showed completely different ion-conductive properties depending on the crystal structure. TPHAP columnar crystals showed a high conductivity of 10⁻³ S cm⁻¹ while retaining their structures even under humid conditions, whereas TPHAP dimer crystals exhibited a conductivity of ∼10⁻⁵ S cm⁻¹ with crystallinity deterioration. The main unit structures induced by multi-interactivity realized different water accessibility, which explains the differences in their ion conductivity and stability against humidity.