ИСТИНА

Halogen bonding (XB) is a non-covalent attractive interaction between heavy halogen atoms (Cl, Br, I) and donors of electron density such as carbonyl oxygen or unsaturated bonds. It complements traditional interaction patterns allowing construction of directional bonds in hydrophobic environment and thus provides new prospective approaches in drug design [1]. However broad application of XB in drug design is now hampered due to the lack of fast and reliable schemes of its description. A focused set of drug-like aromatic fragments with different halogens and substituents was compiled. Several multipole models were fitted to RHF/6-31G* reference MEP. Atomic charges and atomic quadrupole moment on halogen atom as well as electrostatic potential in σ-hole area were studied. Free-Wilson analysis was carried out for additivity tests, and Hansch QSPR models with Hammett constants as descriptors were built. We showed that both inductive and resonance effects are essential for quantitative description of atomic charges. In contrast to charges, atomic quadrupoles are not influenced by resonance interaction. We showed that atomic dipole moment has negligible contribution to XB anisotropy description. This work constitutes the first step to construct an empirical scheme for XB description, which makes possible further rational development aimed at using in scoring functions for virtual screening and QSAR studies.