ISSN:
0749-1581
Keywords:
NMR
;
1H NMR
;
13C NMR
;
15N NMR
;
27Al NMR
;
isothiocyanate
;
complexes
;
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
A multinuclear magnetic resonance (NMR) study of the complexes of aluminum(III) with isothiocyanate ion in water-acetone mixtures has been completed. At temperatures low enough to slow proton and ligand exchange, separate resonance signals are observed for coordinated and bulk H2O (1H) and NCS- (13C, 15N), and Al3+ (27Al) in each complex. The 1H NMR spectra reveal six sets of signals for the complexes, [Al(H2O)6]3+ through [Al(H2O)(NCS)5]2-, including isomers for three of the species. Signal area measurements show a decrease in the Al3+ hydration number with increasing NCS- concentration, as this anion replaces water in the solvation shell. In the 27Al NMR spectra of these systems, signals for seven complexes, [Al(H2O)6]3+ through [Al(NCS)6]3-, are observed, with chemical shifts increasing by about 6 ppm with each additional NCS-. Although broadened somewhat by the Al(III) quadrupole, the 13C and 15N NMR spectra also reveal coordinated NCS- signals for these complexes, including 27Al—N13CS J-coupling in [Al(NCS)6]3-. Area evaluations of the 15N NMR signals provide an excellent complement to the 1H hydration number data. These NMR results demonstrate that a multinuclear approach to the study of solution complexes can provide detailed structural information about the species being formed.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrc.1260330605
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