Characterization of Biaryl Torsional Energetics and its Treatment in OPLS All-Atom Force Fields

The frequency of biaryl substructures
in a database of approved
oral drugs has been analyzed. This led to designation of 20 prototypical
biaryls plus 10 arylpyridinones for parametrization in the OPLS all-atom
force fields. Bond stretching, angle-bending, and torsional parameters
were developed to reproduce the MP2 geometries and torsional energy
profiles. The transferability of the new parameters was tested through
their application to three additional biaryls. The torsional energetics
for the 33 biaryl molecules are analyzed and factors leading to preferences
for planar and nonplanar geometries are identified. For liquid biphenyl,
the computed density and heat of vaporization at the boiling point
(255 °C) are also reported.