Mixed-valent diruthenium (II,III) aliphatic carboxylates: columnar mesophases in dodecylsulfate and octylsulfonate derivatives

Two series of polymeric mixed-valent diruthenium (II,III) aliphatic carboxylates of formula Ru₂O₂C(CH₂)_n-2CH₃]₄X (where X=dodecylsulfate (DOS) anion and n=8, 9, 16 and 18, or X=octylsulfonate (OS) anion and n=8, 10, 12, 14 and 18) were synthesized and characterized. Their liquid crystalline properties and crystalline (Cr) structures were analysed; the Cr phases are lamellar in all cases. For long chain DOS derivatives (n=16 and 18) hexagonal and rectangular columnar mesophases (Col_h and Col_r) with melting temperatures close to 140°C were observed. For long chain OS derivatives (n≥10) a Col_h mesophase was observed, with melting temperatures between 140 and 190°C.