Conformational analysis of cellobiose by electronic structure theories

Adiabatic ϕ/ψ maps for cellobiose were prepared with B3LYP density functional theory. A mixed basis set was used for minimization, followed with 6-31+G(d) single-point calculations, with and without SMD continuum solvation. Different arrangements of the exocyclic groups (38 starting geometries) were considered for each ϕ/ψ point. The vacuum calculations agreed with earlier computational and experimental results on the preferred gas phase conformation (anti-ϕH, syn-ψH), and the results from the solvated calculations were consistent with the (syn ϕH/ψH conformations from condensed phases (crystals or solutions). Results from related studies were compared, and there is substantial dependence on the solvation model as well as arrangements of exocyclic groups. New stabilizing interactions were revealed by Atoms-In-Molecules theory.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Nearly 38,000 B3LYP energies were calculated in vacuum and continuum solvents. ► Impacts of B3LYP versus HF theory, SMD versus COSMO solvation were reported. ► B3LYP and SMD helped agreement with vacuum and crystallographic experiments. ► Mixtures of clockwise and counter-clockwise OH groups can give lower energy. ► New non-bonded interactions were identified with Atoms-In-Molecules theory.