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

Abstract

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. 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 m 2 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.

Gold Nanoparticles Stabilized by Molecular Fullerenols

“…We have also developed fabrication methods for highly oxygenated fullerenols (C 60 (OH) n ⋅xH 2 O, n=36, 40, and 44) that exhibited high water solubility (up to 64.9 mg/mL) with a molecularly dispersed state (particle size: 0.7–2.0 nm) . More recently, physical properties of fullerenols such as reversible sorption‐desorption behavior and dielectric response toward gaseous molecules (H 2 , CO 2 , N 2 , and CH 4 ), and vapor of H 2 O, MeOH and EtOH molecules has been revealed . In addition to the unique properties, fullerenols possess 3D network structural features connected by weak O−H⋅⋅⋅O hydrogen bond in solid state .…”

“…More recently, physical properties of fullerenols such as reversible sorption‐desorption behavior and dielectric response toward gaseous molecules (H 2 , CO 2 , N 2 , and CH 4 ), and vapor of H 2 O, MeOH and EtOH molecules has been revealed . In addition to the unique properties, fullerenols possess 3D network structural features connected by weak O−H⋅⋅⋅O hydrogen bond in solid state . Since fullerenols have a similar chemical motif to oxygenated carbon materials, such as graphene oxide (GO) and oxidized carbon nanotubes (Figure B).…”

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Polyhydroxylated fullerene derivatives (fullerenols: C 60 (OH) 12 and C 60 (OH) 36 ) exhibit excellent stabilizing matrices for gold nanoparticles. Au:C 60 (OH) 12 and Au:C 60 (OH) 36 form hydrophilic colloids and are well dispersed in H 2 O, even though C 60 (OH) 12 itself is barely dissolved in H 2 O. It was estimated that C 60 (OH) 12 forms a two-to three-layered structure with 3D OÀ H···O hydrogen-bonding networks, surrounding approximately 3 nm-sized Au NPs.

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“…The short induction period as well as kinetic and thermodynamic parameters indicated the dynamic mobility of the fullerenol matrix and the hydrophobic nature of the interface between the Au surface and the matrix. 12 : To a test tube (Φ = 30 mm) equipped with a magnetic stir bar were added C 60 (OH) 12 (0.025 mmol), water (19 mL), THF (25 mL) and aqueous HAuCl 4 solution (25 mmol/L, 1.0 mL, 25 μmol). After stirring for 15 min at 25°C, the mixture was cooled to 0°C, and then to this was added aqueous NaBH 4 solution (500 mmol/L, 5.0 mL, 2.5 mmol).…”

“…It would be a unique achievement if the weakly-coordinating unimolecules can be used as a stabilizing matrix because of their intrinsic dynamic behaviors, which includes providing a larger exposed surface and allowing reactants to access the metal surface more easily. In this paper, we report that polyhydroxylated fullerene derivatives (fullerenols: C 60 (OH) 12 used in variety of research fields, in particular, medicinal [10] and materials science. [9,11] We have also developed fabrication methods for highly oxygenated fullerenols (C 60 (OH) n ·xH 2 O, n = 36, 40, and 44) that exhibited high water solubility (up to 64.9 mg/mL) with a molecularly dispersed state (particle size: 0.7-2.0 nm).…”