Solution structure and dynamics of lanthanide(III) complexes of diethylenetriaminepentaacetate: A two-dimensional NMR analysis

Journal Article · Wed Dec 28 04:00:00 EST 1988 · Inorganic Chemistry; (USA)

DOI:https://doi.org/10.1021/ic00299a011· OSTI ID:5305208

Jenkins, B G; Lauffer, R B ^[1]

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1. Massachusetts General Hospital, Boston (USA)

The solution structure and dynamics of lanthanide(III) complexes of diethylenetriaminepentaacetate (DTPA) have been investigated by {sup 1}H NMR. Two-dimensional (2D) exchange spectroscopy (EXSY) enables the determination of solution dynamics. At low temperatures (0-25{degree}C) the complexes Pr(DTPA){sup 2{minus}}, Eu(DTPA){sup 2{minus}}, and Yb(DTPA){sup 2{minus}} are in slow exchange on the NMR time scale, and all 18 proton chemical shifts are resolved. Raising the temperature causes the number of resonances to decrease from 18 to 9, consistent with exchange between two enantiomers. The rates of exchange of the complexes follow the order Pr(III) < Eu(III) < Yb(III). Utilization of 2D correlation spectroscopy (COSY) along with EXSY data as constraints enables assignments of the chemical shifts via calculations of the dipolar shifts. These calculations afford many reasonable solutions with low R factors, and only through the use of the 2D COSY and EXSY data can certain solutions be rejected. The calculations also confirm that the previously published crystal structure of Nd(DTPA){sup 2{minus}} can quite satisfactorily explain the solution structure. In addition , these data indicate that the central acetate moiety is coordinated to the metal in solution.

• OSTI ID: 5305208
• Journal Information: Inorganic Chemistry; (USA), Journal Name: Inorganic Chemistry; (USA) Vol. 27:26; ISSN 0020-1669; ISSN INOCA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102 -- Chemical &amp; Spectral Procedures
400201* -- Chemical &amp; Physicochemical Properties
ACETATES
CARBOXYLIC ACID SALTS
CHEMICAL SHIFT
COMPLEXES
CRYSTAL STRUCTURE
ELEMENTS
MAGNETIC RESONANCE
METALS
NUCLEAR MAGNETIC RESONANCE
PHYSICAL PROPERTIES
RARE EARTH COMPLEXES
RARE EARTHS
RESONANCE
STRUCTURAL CHEMICAL ANALYSIS
TEMPERATURE EFFECTS
THERMODYNAMIC ACTIVITY
THERMODYNAMIC PROPERTIES