Enhancing Phase Transition Temperature in Novel Crown Inclusion Materials through Anion-Substitution Engineering

Graphical The phase transition temperature was enhanced through anion-substitution engineering in two novel crown inclusions. Intermolecular interactions and hydrogen bond were used to explain the increase of phase transition temperature. Host-guest inclusion materials serve as an ideal model for designing phase transition materials. The typical host molecule, 18-crown-6 (1, 4, 7, 10, 13, 16-hexaoxacyclo-octadecane), is known for its strong coordination with amino compounds through N−H⋅⋅⋅O hydrogen-bonding interactions, attracting the attention of numerous scientific researchers. This study presented the successful synthesis and characterization of two host-guest inclusion materials, [(trans-4-aminocyclohexanol)(18-crown-6)][ClO 4 ] ( 1 ) and [(trans-4-aminocyclohexanol)(18-crown-6)][BF 4 ] ( 2 ). Both compounds 1 and 2 underwent reversible phase changes at temperatures of 312 K/305 K and 322 K/314 K, respectively. In this article, crystal structures, thermal properties, optical properties and analyses of intermolecular interactions were discussed in details. Our endeavors are believed to have made a contribution to the advancement of phase change materials.