posted on 2021-06-14, 15:04authored byEkaterina N. Ovchenkova, Arshak A. Tsaturyan, Nataliya G. Bichan, Tatyana N. Lomova
The
basicity thermodynamic parameters of pyridyl/imidazole-substituted
fullero[60]/[70]pyrrolidines with respect to N heteroatoms in dichloromethane,
which are necessary both to deepen insight into aromaticity “neque
levia” and to create supramolecular chemical structures for
application, are obtained and discussed in this work. Because of the
presence of a chromophore in the molecules, the acid–base reactions
of three C60 derivatives functionalized in different ways
and one C70 derivative are studied using spectrophotometric
titration with trifluoroacetic acid. The dependence of the pK values determined using the data on Hammett’s acidity
functions, H0, for a binary nonaqueous
solvent on the molecule’s chemical structure is shown. Density
functional theory (DFT) and time-dependent DFT (TD-DFT) at the B3LYP/6-311G(d,p)
level were used for the optimization of the fullerene derivative structures
and modeling of their UV–vis spectra. The pKBH+ values of substituted fullero[60]/[70]pyrrolidines
are predicted by quantum-chemical calculations.