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The Affinity of Some Lewis Bases for Hexafluoroisopropanol as a Reference Lewis Acid: An ITC/DFT Study
Author(s) -
Milovanović Milan R.,
Dherbassy Quentin,
WencelDelord Joanna,
Colobert Françoise,
Zarić Snežana D.,
Djukic JeanPierre
Publication year - 2020
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.202000560
Subject(s) - lewis acids and bases , chemistry , solvation , isothermal titration calorimetry , implicit solvation , pyridine , density functional theory , chlorobenzene , gibbs free energy , enthalpy , computational chemistry , solvent , organic chemistry , thermodynamics , catalysis , physics
To figure out the possible role of 1,1,1,3,3,3‐hexafluoropropan‐2‐ol (HFIP) as well as to provide reference thermochemical data in solution, the formation of Lewis acid‐base complexes between HFIP (Lewis acid) and a series of 8 different Lewis bases (3 sulfoxides, 3 Nsp 2 pyridine derivatives, 1 aromatic amine, 1 cyclic aliphatic ether) was examined by isothermal titration calorimetry (ITC) experiments and static density functional theory augmented with Dispersion (DFT−D) calculations. Measured ITC association enthalpy values (Δ H a ) lie between −9.3 and −14 kcal mol −1 . Computations including a PCM implicit solvation model produced similar exothermicity of association of all studied systems compared to the ITC data with Δ H a values ranging from −8.5 to −12.7 kcal mol −1 . An additional set of calculations combining implicit and explicit solvation by chlorobenzene of the reactants, pointed out the relatively low interference of the solvent with the HFIP‐base complexation: its main effect is to slightly enhance the Gibbs energy of the HFIP‐Lewis base association. It is speculated that the interactions of bulk HFIP with Lewis bases therefore may significantly intervene in catalytic processes not only via the dynamic microstructuring of the medium but also more explicitly by affecting bonds’ polarization at the Lewis bases.