title: Site-resolved (2)H relaxation experiments in solid materials by global line-shape analysis of MAS NMR spectra.
abstract: We investigate a way one can achieve good spectral resolution in (2)H MAS NMR experiments. The goal is to be able to distinguish between and study sites in various deuterated materials with small chemical shift dispersion. We show that the (2)H MAS NMR spectra recorded during a spin-relaxation experiment are amenable to spectral decomposition because of the different evolution of spectral components during the relaxation delay. We verify that the results are robust by global least-square fitting of the spectral series both under the assumption of specific line shapes and without such assumptions (COmponent-REsolved spectroscopy, CORE). In addition, we investigate the reliability of the developed protocol by analyzing spectra simulated with different combinations of spectral parameters. The performance is demonstrated in a model material of deuterated poly(methacrylic acid) that contains two (2)H spin populations with similar chemical shifts but different quadrupole splittings. In (2)H-exchanged cellulose containing two (2)H spin populations with very similar chemical shifts and quadrupole splittings, the method provides new site-selective information about the molecular dynamics.
authors.affiliation: Division of Applied Physical Chemistry, Department of Chemistry, KTH Royal Institute of Technology, SE-10044 Stockholm, Sweden; Wallenberg Wood Science Center, KTH Royal Institute of Technology, SE-10044 Stockholm, Sweden; Innventia AB, Box 5604, SE-114 86 Stockholm, Sweden.
authors.forename: E L
authors.initials: EL
authors.lastname: Lindh
authors.affiliation: Division of Applied Physical Chemistry, Department of Chemistry, KTH Royal Institute of Technology, SE-10044 Stockholm, Sweden.
authors.forename: P
authors.initials: P
authors.lastname: Stilbs
authors.affiliation: Division of Applied Physical Chemistry, Department of Chemistry, KTH Royal Institute of Technology, SE-10044 Stockholm, Sweden. Electronic address: furo@kth.se.
authors.forename: I
authors.initials: I
authors.lastname: Furó
keywords: Chemical shift; Longitudinal relaxation; Magic angle spinning; Solid state NMR; Spectral resolution