Vibrational analyses with harmonic oscillator approximation were used to confirm the energy-minimum character of the obtained stationary point geometries and to calculate the thermodynamic corrections to the electronic energy at 0, 273.15, 298.15, and 373.15 K (ideal gas at 101.325 kPa and rigid rotor approximations). The structures were first optimized by B3LYP-D3 and the resulting geometries were used as inputs for the optimizations by PBE0-D3 to minimize the conformational variations between the two optimized geometries. Additional single-point energy calculations using the double-and quadruple-ζ cc-pVxZ + aug-cc-pVxZ-PP (Sn) (x = D, Q) basis sets were conducted with the corresponding method. The exponential complete basis set limit (CBS) extrapolation scheme developed by Halkier et at. was then used to obtain refined electronic energies (ECBS) with decreased effects of the Basis Set Superposition Error (BSSE) and the fitting parameters B and α according to eq. 1-3.