Evaluation of density functionals and semiempirical methods for highly fluorinated amines and hydrocarbons

Highly fluorinated solvent compounds are used in a wide variety of applications including lubricant technology, organic synthesis, heat transfer, and battery technology. Our laboratory has developed and validated databases of geometries, dipole moments and potential energy curves for a series of highly fluorinated solvents, including trialkylamines and hydrocarbons, using a large selection of density functional theory levels, coupled-cluster calculations and semiempirical methods. Geometries obtained from high-level DFT help to elucidate the coordinative properties of such solvents, confirming that perfluorinated trialkylamines have nearly perfectly planar geometry at their nitrogen centers, and owe their inertness primarily to negligible basicity and a vanishing dipole moment. The MPW1B95, TPSSh and B97-2 functionals performed especially well against experiment for our compound set and should prove useful for analyzing perfluorinated solvents of industrial, environmental and biological importance.