Synthesis, molecular structure, and properties of DABCO bromide based ionic liquid combining spectroscopic studies with DFT calculations

Through N-alkylation of 1,4-diazabicyclo [2.2.2] octane with 1-bromooctane a new ionic liquid, namely 1?octyl?1,4?diazabicyclo octan?1?ium Bromide [C8DABCO+][Br?] has been synthesized and characterized by FT-IR, FT-Raman 1H 13C-NMR spectroscopies. Three C-H•••Br bonds were predicted natural bond orbital (NBO), atoms in molecules (AIM) calculations orders but monodentate coordination between cation anion is suggested because only one them higher energy lower distance. The effect Br on properties IL clearly observed the change orientation direction dipole moment vector IL, as compared cation. NBO studies reveal that strongly stabilizes to form IL. complete vibrational assignments 129 132 vibration modes expected for its performed using two harmonic force fields SQMFF methodology transferable scaling factors. scaled constants also reported both species. confers reactivity [C8DABCO+][Br?], analyses frontier orbitals. Reasonable correlations found experimental IR, Raman NMR spectra corresponding theoretical ones.