Molecular Electrostatic Potential and Noncovalent Interactions in Derivatives of Group 8 Elements

This communication reports experimental and theoretical evidences of sigma-hole interactions in adducts between nitrogen or oxygen nucleophiles and tetroxides of osmium or other group 8 elements. Cocrystals between pyridine or pyridine N-oxide derivatives and osmium tetroxide are characterized through various techniques and rationalized as sigma-hole interactions using DFT calculations and several other computational tools. We propose the term "osme bond" (OmB, Om=Fe, Ru, Os, (Hs)) for naming the noncovalent interactions wherein group 8 elements have the role of the electrophile. The word osme is the transcription of the ancient Greek word for smell that was used to name the heaviest group 8 element in relation to the smoky odor of its tetroxide.