Vibrational and Nuclear Magnetic Resonance Properties of 2,2′-Biquinolines: Experimental and Computational Spectroscopy Study

Abstract

Experimental (IR, Raman and NMR) techniques and quantum chemical (DFT) methods have been applied to investigate the vibrational and NMR properties of a new ligand based on 2,2′-biquinoline (bq) functionalized with polar hydrophilic tetraethylene glycol monomethylether (TEG) chains (bq_TEG). Vibrational and NMR spectra of the ligand have been explained based on DFT computational data obtained at B3LYP/6-311+G(d,p) level of theory. For the spectroscopic analysis we started from the parent molecule 2,2′-biquinoline and explained the changes in the spectra of bq_TEG in close relation to the corresponding spectra of bq. Our data point to a trans conformation of bq_TEG in solid state, as wells as in liquid phase. The excellent agreement between the experimental and computed data allowed for a reliable assignment of the vibrational and NMR spectra, both for bq and bq_TEG.