Related Experiment Videos
Benchmark study of DFT functionals for late-transition-metal reactions
Miriam M Quintal1, Amir Karton, Mark A Iron
1Department of Organic Chemistry, Weizmann Institute of Science, 76100 Rehovot, Israel.
The Journal of Physical Chemistry. A
|January 13, 2006
Summary
DFT functionals perform differently for transition metals. General-purpose functionals like PBE0, B1B95, and PW6B95 are recommended for late-transition-metal reactions, outperforming specialized "kinetics" functionals.
Area of Science:
- Computational Chemistry
- Quantum Chemistry
- Materials Science
Background:
- Density Functional Theory (DFT) is crucial for modeling chemical reactions.
- Accurate prediction of transition metal catalysis requires reliable exchange-correlation functionals.
- Previous studies often focused on main-group elements, leaving transition metal systems less explored.
Purpose of the Study:
- To evaluate the performance of various DFT exchange-correlation functionals for late-transition-metal reaction profiles.
- To establish benchmark ab-initio reference data for key prototype reactions involving palladium.
- To identify optimal functionals for modeling transition metal catalysis.
Main Methods:
- Ab-initio calculations were performed for prototype reactions (e.g., Pd + H2, Pd + CH4, Pd + C2H6, Pd + CH3Cl).
- Lesser quality ab-initio data were obtained for acetone hydrogenation and the Heck reaction.
- Performance of DFT functionals was assessed against benchmark data, considering both transition-metal and main-group reactions.
Main Results:
- "Kinetics" functionals showed poor performance for late-transition-metal reactions compared to general-purpose ones.
- A cluster of functionals (PBE0, B1B95, PW6B95, TPSS25B95) demonstrated comparable, good performance.
- B1B95 and PW6B95 emerged as top performers when main-group thermochemistry was also considered.
- TPSS25B95 and TPSS33B95 offer compromises for specific needs like weak interactions or main-group barrier heights.
- Basis set superposition errors (BSSE) were reduced by ensuring radial flexibility in the metal spd shell.
- Optimal HF percentages in hybrid functionals vary with system charge and type.
Conclusions:
- No single "best" DFT functional exists for all late-transition-metal reactions; a group of functionals performs well.
- General-purpose functionals are superior to "kinetics" functionals for these systems.
- Specific functionals like B1B95 and PW6B95 are recommended for broad applicability.
- Careful basis set selection and understanding HF percentage effects are important for accurate ab-initio calculations.