A nuclear magnetic resonance study of molecular motion and ‘guest’ structure in the clathrate hydrates of (i-C5H11)4NF and (n-C4H9)4NF

Abstract

The proton magnetic resonance linewidth and second moments between 77°k and 286°k for i-amyl groups of molecules included as guests in the clathrate hydrate of (i-C₅H₁₁)₄NF have been interpreted in terms of simple motional models of these guest moieties. The results complement the reported details of crystal structure of this clathrate. For the analogous hydrate containing guest n-butyl groups, proton magnetic resonance second moments in the same temperature range have supported the disordered guest structure reported from a previous x-ray diffraction study. In addition, hysteresis has been found in the second moment curve of this clathrate beyond 248°k, and this has been ascribed to a phase transition.