Aliphatic C-H/pi interactions: Methane-benzene, methane-phenol, and methane-indole complexes

Area of Science:

• Biochemistry
• Computational Chemistry
• Molecular Interactions

Background:

• Noncovalent C-H/pi interactions are fundamental in biological systems, influencing molecular recognition.
• Understanding these interactions is key to deciphering complex biochemical processes.

Purpose of the Study:

• To investigate the potential energy curves of methane-aromatic complexes as models for C-H/pi interactions.
• To provide accurate interaction energies for systems mimicking interactions involving phenylalanine, tyrosine, and tryptophan.

Main Methods:

• Utilized second-order Møller-Plesset perturbation theory (MP2) with augmented correlation-consistent basis sets (aug-cc-pVDZ and aug-cc-pVTZ).
• Employed coupled-cluster theory with perturbative triples [CCSD(T)] for higher-order electron correlation corrections.
• Applied symmetry-adapted perturbation theory (SAPT) to dissect the components of the interaction energy.

Main Results:

• Calculated potential energy curves for methane-benzene, methane-phenol, and methane-indole complexes.
• Estimated highly accurate interaction energies at the CCSD(T)/aug-cc-pVTZ level through additive approximations.
• Decomposed interaction energies into physically meaningful components using SAP তত্ত্ব.

Conclusions:

• The study provides valuable quantitative data on C-H/pi interactions relevant to biochemistry.
• The computational methods employed offer a robust framework for studying similar noncovalent interactions.
• Findings contribute to a deeper understanding of molecular recognition in biological systems.