Dielectric and Sorption Responses of Hydrogen-Bonding Network of Amorphous C₆₀(OH)₁₂ and C₆₀(OH)₃₆

Hydrophilic fullerene derivatives of C₆₀(OH)₁₂ (1) and C₆₀(OH)₃₆ (2) bearing different numbers of −OH groups formed amorphous solids of 1·x(H₂O) (x = 5–10) and 2·x(H₂O) (x = 15–22), respectively, according to the humidity. The thermally activated dynamic molecular motion of polar H₂O was confirmed in the DSC and dielectric spectra. Three-dimensional O–H···O hydrogen-bonding networks in amorphous 1 and 2 produced extrinsic adsorption–desorption pores with a hydrophilic environment posed by −OH groups, where N₂, CO₂, H₂, and CH₄ gases vapors and polar H₂O, MeOH, and EtOH molecules reversibly adsorbed into the networks. The molecular motion of polar H₂O was directly observed in dielectric enhancement and protonic conductivity in three-dimensional O–H···O hydrogen-bonding networks. The Brunauer–Emmett–Teller (BET) specific surface areas of amorphous 1 and 2 were 315 and 351 m² g^–1, respectively, from the CO₂ sorption isotherms. Reversible vapor sorption behaviors with structural changes of amorphous 1 and 2 were also confirmed for the polar H₂O, MeOH, and EtOH.