Accurate, precise, and efficient theoretical methods to calculate anion-π interaction energies in model structures

Area of Science:

• Computational chemistry
• Supramolecular chemistry
• Chemical physics

Background:

• Anion-π interactions are vital for designing anion receptors and channels.
• Accurate and efficient computational methods for describing anion-π interactions are lacking.
• Understanding these interactions advances supramolecular chemistry.

Purpose of the Study:

• To establish benchmark interaction energies for anion-π complexes using high-level computational methods.
• To evaluate the accuracy and efficiency of various computational methods, including density functional theory (DFT) approximations.
• To provide reliable reference data for the anion-π interaction in binary and ternary complexes.

Main Methods:

• Calculated anion-π interaction energies for 20 binary and 30 ternary complexes.
• Used domain-based local-pair natural orbital coupled cluster (LPNO-CEPA) extrapolated to the complete basis set limit as reference.
• Employed symmetry-adapted perturbation theory (SAPT) to analyze interaction components.
• Assessed methods like direct random phase approximation (dRPA), SOSEX, LPNO-CEPA, and dispersion-corrected DFT functionals.

Main Results:

• LPNO-CEPA/1 provided the best agreement with reference values.
• Direct random phase approximation (dRPA) showed high accuracy and precision, being 6-17 times more efficient than LPNO-CEPA/1 for binary complexes.
• Dispersion-corrected double hybrid functionals performed better than GGA and meta-GGA functionals but were less accurate than dRPA.

Conclusions:

• Domain-based local-pair natural orbital coupled cluster energies serve as reliable reference values for anion-π interactions.
• Direct random phase approximation (dRPA) offers a computationally efficient and accurate alternative for large-scale studies.
• The study provides valuable insights into the performance of various computational methods for describing anion-π interactions.