Experimental and Theoretical Spectroscopic Studies on Selected Igepals

Several nonionic igepals characterized by the formula (C$\text{}_{m}$H$\text{}_{2m+1}$)-C$\text{}_{6}$H$\text{}_{4}$ (OCH$\text{}_{2}$CH$\text{}_{2}$)$\text{}_{n}$OH were investigated by high resolution NMR and IR spectroscopy. Gauge invariant atomic orbital density functional theory NMR calculations on model molecules in the gas phase additionally supported the assignment of experimental carbon signals. Different orientations of individual sub-units of an aliphatic chain relative to external magnetic field and trans-gauche transitions were assumed to explain complex patterns of carbon spectra in the aliphatic region of igepals with linear alkyl chain.