NMR study of extracted compounds of trioctylalkylammonium with rare earth nitrates

¹H and ¹³C NMR was used to investigate the structure of ion pairs formed by trioctylalkylammonium (alkyl = CH₃-C₈H₁₇) cation and rare earth-containing anions in nitrobenzene. The cation-anion distance in the investigated compounds increases from trioctylmethyl to trioctylbutylammonium salt, remaining constant with further growth of the n-alkyl chain. The ion pair formation changes the conformation equilibrium of the cation alkyl radicals to make easier the cation-counter-ion contact.