Probing the Dynamics of Layered Double Hydroxides by Solid-State (27)AI NMR Spectroscopy

摘要

In order to shed light,on molecular dynamics and structure in layered materials, (27)AI NMR spectra of layered double hydroxides (LDHs) were investigated by varying the layer charge density, the cations of the sheets, the interlayer anions, the hydration state, and the temperature. This study reveals that most of the broadening of (27)AI satellite transitions in LDHs is due to dynamics within the interlayer space rather than the chemical environment of (27)AI in the sheets, i.e., cation disorder. This finding provides a new solid-state NMR tool to probe dynamics in aluminum-bearing layered materials which does not require tensor calculations, which is based on direct acquisition spectra and which provides long-range information as the (27)AI spectra are sensitive to dynamics that occur 3-5 angstrom away from the observed nuclei.