ISSN:
0749-1581
Keywords:
Metalloporphyrins
;
Aromatic compounds
;
Molecular complexes
;
Stability constants
;
Paramagnetic NMR shifts
;
Paramagnetic relaxation
;
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
1H NMR shifts and 13C spin-lattice relaxation rates were measured for various aromatic π-acceptors (S) in solutions containing paramagnetic cobalt(II) and iron(III) porphyrins (P). The stability constants of P · S molecular complexes and limiting values of substrate chemical shifts in the complexes were determined from the concentration dependence of chemical shifts. The abilities of different substituents to promote complexation of aromatics with metalloporphyrins are discussed. The preferred substrate orientation in molecular complexes were derived using relative values of chemical shifts and relaxation rates induced by metalloporphyrins. Both monocyclic (benzene and pyridine derivatives) and bicyclic (naphthalene derivative) substrates tend to form ‘axially symmetric’ adducts with parallel π-planes and the centre of the aromatic system situated in the vicinity of the porphyrin z-axis.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrc.1260290711
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