Role of Anions (Tetrafluoroborate, Perchlorate) of Tetrabutylammonium Salts in Determining Solvation Effects Prevailing in Industrially Essential Solvents Probed by Conductance and FT-IR Spectra

Abstract

Molecular interactions of tetrabutylammonium salts prevailing in organic solvent media have been analyzed, both qualitatively and quantitatively, using conductometric studies and validating the results with Fourier transform infrared (FT-IR) measurements. From conductometric studies of tetrabutylammonium tetrafluoroborate [Bu4NBF4] and tetrabutylammonium perchlorate [Bu4NClO4] in nitromethane (NM), N-methyl formamide (NMF), and formamide (FA) at 298.15 K, it is revealed that high molecular interaction is mainly because of ion–dipole interactions, which is evidenced from the FT-IR measurements. The 1978 Fuoss conductance-concentration equation in terms of the limiting molar conductance (Λo), the association constant (KA), and the association diameter (R) was used to interpret the conductance data. Tetrabutylammonium tetraphenylborate [Bu4NBPh4] as the “reference electrolyte” was used to estimate the ionic contributions to the limiting molar conductance. The degree of interaction is articulated in terms of the association constant (KA), which illustrates that viscosity of the solvent plays an important role in the ion–dipole interaction.The ionic interaction obtained is highest in the case of [Bu4NBF4] and FA in comparison to the other systems. The consequences have been considered in terms of dipole–dipole interactions, hydrogen bond formation, structural feature, and configurational theory. The FT-IR spectroscopic studies of the variational intensity of characteristic bands of the solvents have been undertaken, and the solvation phenomenon is evidenced by the change of band intensities owing to the occurrence of the electrolytes.