Three-Dimensional CH/π and CH/N Interactions from Quantum-Mechanical and Database Analyses.

Quantum mechanical (QM)-level molecular interaction fields (MIFs) are three-dimensional potential maps that describe the intermolecular interactions surrounding a target molecule, derived through QM calculations. This study employs QM-level MIFs (MIFs(QM)) and analyses of the Cambridge Structural Database (CSD) to uncover the three-dimensional characteristics of CH/π and CH/N interactions in typical nitrogen-containing heterocyclic compounds. Our findings confirm the reliability and applicability of MIF(QM) calculations for analyzing CH/π and CH/N interactions. Additionally, we propose approximation functions of MIFs(QM) and demonstrate that the resulting MIFs(func) are effective for studying CH/π and CH/N interactions in protein/ligand systems.