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Structural characterization of silver dialkylphosphite salts using solid‐state 109 Ag and 31 P NMR spectroscopy, IR spectroscopy and DFT calculations
Author(s) -
Chen Fu,
Wasylishen Roderick E.
Publication year - 2010
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.2572
Subject(s) - chemistry , tautomer , nmr spectra database , spectroscopy , nuclear magnetic resonance spectroscopy , dimer , crystallography , solid state nuclear magnetic resonance , analytical chemistry (journal) , chemical shift , phosphorus 31 nmr spectroscopy , spectral line , stereochemistry , nuclear magnetic resonance , organic chemistry , physics , quantum mechanics , astronomy
High‐resolution solid‐state 109 Ag and 31 P NMR spectroscopy was used to investigate a series of silver dialkylphosphite salts, Ag(O)P(OR) 2 (R = CH 3 , C 2 H 5 , C 4 H 9 and C 8 H 17 ), and determine whether they adopt keto, enol or dimer structures in the solid state. The silver chemical shift, CS, tensors and | J ( 109 Ag, 31 P)| values for these salts were determined using 109 Ag (Ξ = 4.652%) NMR spectroscopy. The magnitudes of J ( 109 Ag, 31 P) range from 1250 ± 10 to 1318 ± 10 Hz and are the largest reported so far. These values indicate that phosphorus is directly bonded to silver for all these salts and thus exclude the enol structure. All 31 P NMR spectra exhibit splittings due to indirect spin–spin coupling to 107 Ag ( I = 1/2, NA = 51.8%) and 109 Ag ( I = 1/2, NA = 48.2%). The 1 J ( 109 Ag, 31 P) values measured by both 109 Ag and 31 P NMR spectroscopy agree within experimental error. Analysis of 31 P NMR spectra of stationary samples for these salts allowed the determination of the phosphorus CS tensors. The absence of characteristic PO stretching absorption bands near 1250 cm −1 in the IR spectra for these salts exclude the simple keto tautomer. Thus, the combination of solid‐state NMR and IR results indicate that these silver dialkylphosphite salts probably have a dimer structure. Values of silver and phosphorus CS tensors as well as 1 J ( 109 Ag, 31 P) values for a dimer model calculated using the density functional theory (DFT) method are in agreement with the experimental observations. Copyright © 2010 John Wiley & Sons, Ltd.