Orthogonal dipolar interactions between amide carbonyl groups.

ABSTRACT: Orthogonal dipolar interactions between amide C=O bond dipoles are commonly found in crystal structures of small molecules, proteins, and protein-ligand complexes. We herein present the experimental quantification of such interactions by employing a model system based on a molecular torsion balance. Application of a thermodynamic double-mutant cycle allows for the determination of the incremental energetic contributions attributed to the dipolar contact between 2 amide C=O groups. The stabilizing free interaction enthalpies in various apolar and polar solvents amount to -2.73 kJ mol(-1) and lie in the same range as aromatic-aromatic C-H...pi and pi-pi interactions. High-level intermolecular perturbation theory (IMPT) calculations on an orthogonal acetamide/N-acetylpyrrole complex in the ga

SUBMITTER: Fischer FR 

PROVIDER: S-EPMC2582285 | biostudies-literature | 2008 Nov

REPOSITORIES: biostudies-literature