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Solid‐state 109 Ag CP/MAS NMR spectroscopy of some diammine silver(I) complexes
Author(s) -
Bowmaker Graham A.,
Harris Robin K.,
Assadollahzadeh Behnam,
Apperley David C.,
Hodgkinson Paul,
Amornsakchai Pornsawan
Publication year - 2004
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1427
Subject(s) - chemistry , nmr spectra database , anisotropy , selenate , spectral line , analytical chemistry (journal) , crystallography , solid state nuclear magnetic resonance , nuclear magnetic resonance spectroscopy , magic angle spinning , nuclear magnetic resonance , stereochemistry , selenium , physics , organic chemistry , chromatography , quantum mechanics , astronomy
Solid‐state cross‐polarization magic‐angle spinning (CP/MAS) NMR spectra were recorded for the compounds [Ag(NH 3 ) 2 ] 2 SO 4 , [Ag(NH 3 ) 2 ] 2 SeO 4 and [Ag(NH 3 ) 2 ]NO 3 , all of which contain the linear or nearly linear two‐coordinate [Ag(NH 3 ) 2 ] + ion. The 109 Ag CP/MAS NMR spectra show centrebands and associated spinning sideband manifolds typical for systems with moderately large shielding anisotropy, and splittings due to indirect 1 J ( 109 Ag,14N) spin–spin coupling. Spinning sideband analysis was used to determine the 109 Ag shielding anisotropy and asymmetry parameters Δσ and η from these spectra, yielding anisotropies in the range 1500–1600 ppm and asymmetry parameters in the range 0–0.3. Spectra were also recorded for 15 N and (for the selenate) 77 Se. In all cases the number of resonances observed is as expected for the crystallographic asymmetric units. The crystal structure of the selenate is reported for the first time. One‐bond ( 107, 109 Ag, 15 N) coupling constants are found to have magnitudes in the range 60–65 Hz. Density functional calculations of the Ag shielding tensor for model systems yield results that are in good agreement with the experimentally determined shielding parameters, and suggest that in the solid compounds Δσ and η are reduced and increased, respectively, from the values calculated for the free [Ag(NH 3 ) 2 ] + ion (1920 ppm and 0, respectively), primarily as a result of cation–cation interactions, for which there is evidence from the presence of metal‐over‐metal stacks of [Ag(NH 3 ) 2 ] + ions in the solid‐state structures of these compounds. Copyright © 2004 John Wiley & Sons, Ltd.