Remote halogen switch of amine hydrophilicity

Abstract

Bromide and iodide anions switch hydrogen-bonding patterns in otherwise isostructural dimethanol solvates N-methyl-1,4-diazabicyclo[2.2.2]octanium bromide (dabcoCH₃Br·2CH₃OH) and analogous iodide (dabcoCH₃I·2CH₃OH), both synthesized in the high-pressure version of the Menshutkin reaction at 1.2 and 2.4 GPa, respectively. The magnitudes of the high pressure triggering these reactions correspond to identical molecular volumes of both solvates.