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Determination of polyaminocarboxylate ligand denticity by 13 C NMR paramagnetic line broadening
Author(s) -
Popov K.,
Vendilo A.,
Djatlova N.
Publication year - 1991
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.1260290403
Subject(s) - chemistry , denticity , paramagnetism , ethylenediaminetetraacetic acid , ligand (biochemistry) , selectivity , crystallography , inorganic chemistry , chelation , nuclear magnetic resonance , crystal structure , catalysis , organic chemistry , receptor , biochemistry , physics , quantum mechanics
The 13 C NMR characteristics of sodium acetate and complexes of ethylenediaminetetraacetic acid (EDTA, H 4 edta) with La 3+ and VO 2 + in the presence of the paramagnetic relaxant [Gd(H 2 O) n edta] − are reported. The observed selective paramagnetic line broadening of the uncoordinated glycinate arms in [VO 2 edta] 3− permits an assignment of the 13 C resonances and independent ligand denticity determination. For COO resonances the selectivity was found to be ca . 18. A large difference was also observed between the 13 C transverse relaxation times for the uncoordinated COO groups of CH 3 COO − and the coordinated COO groups of [La(H 2 O) 3 edta] − . The magnitude of the selectivity provides clear advantages in aiding the 13 C NMR assignment and the establishment of the true denticity for the complexes of polydentate ligands.