The relative strength and role in crystal packing of I⁻⋯π and CH⋯I⁻interactions in iminium salts

Abstract

The relative energy and importance of Hal À /p and CH/Hal À interactions were studied basing on the crystal structures of iminium salts with different I/C distances. DFT calculations of the corresponding cations and ionic pairs were performed in an isolated state, accompanied by PW-DFT calculations of the crystals. The QTAIM methods in conjunction with the Espinosa-Lecomte correlation scheme were used to estimate the energies of C/I and H/I interactions both in isolated and in solid state. A detailed CSD survey was performed to estimate the relative abundance of these interactions in iminium salts.

Relationships between interaction energy, intermolecular distance and electron density properties in hydrogen bonded complexes under external electric fields

“…From all the properties p that can be used for the estimation of E HB ; V b has become popular because of the simple estimator E HB ¼ À0:5V b derived from a combination of experimental data and theoretical calculations [5]. This estimator, initially derived for HÁ Á ÁO hydrogen bonds, has been applied to many other intermolecular interactions, as for example AuÁ Á ÁH [7] or IÁ Á Áp [37] interactions.…”