TY - JOUR

T1 - Se-77 solid-state NMR of inorganic and organoselenium systems

T2 - a combined experimental and computational study

AU - Griffin, John M.

AU - Knight, Fergus R.

AU - Hua, Guoxiong

AU - Ferrara, Jeanette S.

AU - Hogan, Simon W. L.

AU - Woollins, J. Derek

AU - Ashbrook, Sharon E.

PY - 2011/6/2

Y1 - 2011/6/2

N2 - Experimental Se-77 NMR parameters for 17 selenium-containing compounds have been determined by analysis of Se-77 solid-state NMR spectra. These are compared to values obtained from first-principles gauge including projector augmented wave (or GIPAW) calculations performed on geometry-optimized crystal structures. Good agreement is observed between experimental and calculated values across a wide chemical shift range, enabling assignment of the experimental Se-77 NMR spectra for compounds containing more than one crystallographically distinct selenium site. Calculations for isolated molecules extracted from the optimized structure reveal that intermolecular interactions have a relatively small effect on isotropic shifts in general, but larger effects on the chemical shift anisotropy are observed for some compounds. Further calculations for a model structure give insight into the effects of local bonding geometry on the Se-77 chemical shift in a diselenide linkage. The Se-77 chemical shift is found to be highly sensitive to torsional angles that define the geometry of the diselenide linkage, and this leads to an understanding of the origins of the large chemical shift differences observed between chemically equivalent selenium sites for one of the compounds studied in this work.

AB - Experimental Se-77 NMR parameters for 17 selenium-containing compounds have been determined by analysis of Se-77 solid-state NMR spectra. These are compared to values obtained from first-principles gauge including projector augmented wave (or GIPAW) calculations performed on geometry-optimized crystal structures. Good agreement is observed between experimental and calculated values across a wide chemical shift range, enabling assignment of the experimental Se-77 NMR spectra for compounds containing more than one crystallographically distinct selenium site. Calculations for isolated molecules extracted from the optimized structure reveal that intermolecular interactions have a relatively small effect on isotropic shifts in general, but larger effects on the chemical shift anisotropy are observed for some compounds. Further calculations for a model structure give insight into the effects of local bonding geometry on the Se-77 chemical shift in a diselenide linkage. The Se-77 chemical shift is found to be highly sensitive to torsional angles that define the geometry of the diselenide linkage, and this leads to an understanding of the origins of the large chemical shift differences observed between chemically equivalent selenium sites for one of the compounds studied in this work.

KW - NUCLEAR-MAGNETIC-RESONANCE

KW - CHEMICAL-SHIFT TENSORS

KW - CRYSTAL-STRUCTURE

KW - 1ST-PRINCIPLES CALCULATIONS

KW - SHIELDING TENSORS

KW - X-RAY

KW - RELAXATION-TIME

KW - SPECTROSCOPY

KW - SELENIUM

KW - O-17

U2 - 10.1021/jp202550f

DO - 10.1021/jp202550f

M3 - Journal article

VL - 115

SP - 10859

EP - 10872

JO - The Journal of Physical Chemistry C

JF - The Journal of Physical Chemistry C

SN - 1932-7447

IS - 21

ER -