Characterization of tetramethyl guanidinium ۴-nitro phenoxide (TMG-NP) and tetraphenyl guanidinium ۴-nitro phenoxide (TPG-NP) as new ionic liquids (ILs) using DFT and ab initio

Here, we have been evaluated the geometrical, electronic and spectroscopic characters of TMG-NP and TPG-NP, at DFT vs. ab initio. Assessment of these ILs have been done via the optimized structures using B۳PW۹۱, ωb۹۷xd and HF/۶-۳۱۱++G(d,p). The spectral analysis of both ILs is containing IR, Raman, ۱H NMR,۱۳C NMR, and UV–Vis. Both TMG-NP & TPG-NP with high polarizability, hyperpolarizability (βtot) and polarity are proposed as molecules with high NLO character. These characters are comparable with those of the related standards to urea structure. The calculated βtot values for TMG-NP, especially TPG-NP structure are found to be about ۳۱.۵ - ۴۵.۵ times greater than the βtot value of urea, leading us to consider these structures as the suitable candidates for NLO materials. Both systems display differentially Eg (band gap), global reactivity, charge delocalization and DOS plot that are realized via NBO analysis. The electron density transfers from the electropositive atoms to the electronegative atoms, because of electronegative difference of them that is recognized via MEP analysis. Less stability and more reactivity of TPG-NP than TMG-NP arising from less hyperconjugation, more π-stacking and more steric effect of TPG-NP than TMG-NP. Finally, in order to reduction in friction along with wear, TPG-NP with higher nucleophilicity and lower electrophilicity than TMG-NP, is suggested as better noncorrosive lubricant additive for tribological performance.

کلیدواژه ها:

ILs ، TPG-NP ، TMG-NP ، ωb۹۷xd ، HF