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Low Temperature 1 H‐, 19 F‐, and 31 P‐PGSE Diffusion Measurements. Applications to Cationic Alcohol Complexes
Author(s) -
MartínezViviente Eloísa,
Pregosin Paul S.
Publication year - 2003
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.200390190
Subject(s) - chemistry , cationic polymerization , diffusion , trifluoromethanesulfonate , alcohol , analytical chemistry (journal) , tungsten , polymer chemistry , organic chemistry , thermodynamics , catalysis , physics
The problems associated with low‐temperature pulsed‐gradient spin‐echo (PGSE) NMR diffusion measurements are discussed. The influence of convection is overcome by employing a coaxial insert inside a normal 5 mm NMR tube. By means of this configuration, correct diffusion constants and temperature‐independent hydrodynamic radii can be obtained. Low‐temperature 1 H‐, 19 F‐, and 31 P‐PGSE measurements on unstable cationic alcohol complexes of palladium and tungsten (in MeOH and CH 2 Cl 2 ) are reported. For [W(Cp)(adamant‐1‐ol)(CO) 3 ](CF 3 SO 3 ), a strong hydrogen bond between the alcohol OH group and the trifluoromethanesulfonate anion is demonstrated.