Hydrogen bonds between hydrogen halides and unsaturated hydrocarbons

Abstract

Ab initio molecular orbital theory is used to study geometrics and energies of hydrogen-bonded complexes between hydrogen fluoride, hydrogen chloride (as proton donors) and acetylene, ethylene (as proton acceptors). Symmetrical T-shaped structures are found to be equilibrium structures for all four complexes. The strengths of the hydrogen bonds are found to be less than for conventional hydrogen bonds involving lone pairs of electrons.