Molecular dynamics in comb-like ionene as studied by NMR

Proton and fluorine second moment and spin-lattice relaxation timesT ₁ andT _lρ have been employed to study molecular dynamics in the comb-like I-6,6-16-Me-BF₄ ionene in the temperature range from 110 up to 300 K. The existence of motions of methyl groups, trans-gauche isomerization, and/or rotation of the main- and side-chain méthylene groups, as well as isotropic reorientation of tetrafluoroborate ions were established. The observed relaxation behaviors are explained by motional models which assume Davidson-Cole asymmetrical distribution of correlation times. The best-fit motional parameters are given.