Carbon-13 nuclear magnetic resonance study of metal complexes of ethylenedinitrilo-NNN′N′-tetra-acetic acid (H4edta)
- 1 January 1974
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in J. Chem. Soc., Dalton Trans.
- No. 20,p. 2271-2276
- https://doi.org/10.1039/dt9740002271
Abstract
1 H-Decoupled 13C n.m.r. spectra of ZnII, CdII, HgII, PbII, TlI, AlIII, and CoIII complexes of edta4– and Hedta3– are reported. The results confirm and extend earlier studies of the labile complexes of ZnII, CdII, HgII, and PbII, and reveal averaged hyperfine couplings between the carboxylate carbon atoms and IIICd or 113Cd [2J(C–Cd) 12·1 Hz] or 199Hg [2J(C–Hg) 35 Hz]. Aluminium(III) gives an unsymmetrical complex at high pH. Spectra of complex ions of the type [CoIII(edta)X]n– or [CoIII(Hedta)X](n–1)–(X = Cl, Br, NO2, OH, or OH2) confirm the expected quinquedentate co-ordination of edta4– and reveal that only one (‘equatorially’ substituted) isomer is present, except when X = Br where two distinct isomers (‘axial’ and ‘equatorial’) exist. A previously reported single isomer of [CoIII(edta) Br]2– is tentatively assigned an axial structure instead of the expected equatorial configuration.Keywords
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