A Quantum Chemical Study of the Acidity of Acetylene and 1,2-Dihydrobuckminsterfullerene Derivatives

Abstract

DFT PBE0/cc-pVDZ method and the polarizable continuum model were used to determine pK_a values for buckminsterfullerene-acetylene hybrids C₆₀HCCH, C₆₀HCN, tert-butylacetylene, and propyne relative to tert-BuC₆₀H in a vacuum, carbon disulfide, tetrahydrofuran, and dimethyl sulfoxide. The energies of the СH-acid molecule and the carbanion (fulleride- or acetylide anion) were calculated using the same number of Gaussian orbitals. The surfaces of cavities formed by molecules and anions in a solvent are composed of spheres encompassing both atomic nuclei and lone electron pairs. An additional sphere excludes the solvent from the inner cavity of the fullerene.