Predicting Enthalpies of Formation of Geminal Dicationic Ionic Liquids Using High Level Quantum Chemistry Calculations

In recent years many experimental and theoretical investigations on the ionic liquids (ILs) have beenpublished. Most of these investigations are concentrated on the monocationic ionic liquids. The geminaldicationic ionic liquids is a new generation of ILs which introduced by Armstrong et al. [1]. At the present,theoretical studies of the dicationic ILs are scarce.In this work, quantum mechanical calculations are used to predict enthalpies of formation, Hfo, ofdicationic ionic liquids by Gaussian-3 theory using reduced Moller-Plesset order (G3(MP2)) [2], one of themost successful and widely used composite methods in calculating the enthalpies of formations ofdifferent classes of compounds. The cations considered are pyrrolidinium, [mpyC3mpy] +2, imidazolium,[mimC3mim] +2, triazolium, [triC3tri] +2, tetrazolium, [tetC3tet] +2, and pentazolium, [penC3pen] +2,dications. Two cations were joined via a propane linkage chain. The Hfo of dications are predicted byatomization and isodesmic reaction approaches using G3(MP2). Gaussian09 [3] is used forthermochemistry calculations. The all enthalpies of formation are large and positive. A good agreementbetween the atomization and isodesmic approaches is evident. The magnitude of the Hfo follows thetrends [mpyC3mpy] +2 < [mimC3mim] +2 < [triC3tri] +2 < [tetC3tet] +2 < [penC3pen] +2. As we seen, withincreasing the nitrogen content of the five membered rings, enthalpies of formation of the dications areincreased.

کلیدواژه ها:

Thermochemistry ، Enthalpy of Formation ، Dicationic Ionic Liquids ، Computational Study ، G3MP2