Synthesis, characterization, and crystal structures of M(DO3A) (M = Fe, Gd) and Na[M(DOTA)] (M = Fe, Y, Gd)

Journal Article · Wed Aug 04 00:00:00 EDT 1993 · Inorganic Chemistry; (United States)

DOI:https://doi.org/10.1021/ic00068a020· OSTI ID:5110644

Chang, C A; Francesconi, L C; Malley, M F; Kumar, K; Gougoutas, J Z; Tweedle, M F ^[1]; Lee, D W; Wilson, L J ^[2]

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1. Bristol-Meyers Squibb Pharmaceutical Research Institute, Princeton, NJ (United States)
2. William Marsh Rice Univ., Houston, TX (United States)

Macrocyclic amino carboxylate (DOTA and DO3A, where DOTA is 1,4,7,10-tetrakis(carboxymethyl)-1,4,7,10-tetraazacyclododecane and DO3A is 1,4,7-tris(carboxymethyl)-1,4,7,10-tetraazacyclododecane) complexes of Gd(III) and Fe(III) have been synthesized, characterized, and evaluated for use as potential contrast agents for magnetic resonance imaging (MRI). X-ray single-crystal analyses reveal four nitrogens and three oxygens coordinated to the iron in both Na[Fe(DOTA)][center dot]5H[sub 2]O and Fe(DO3A)[center dot]3H[sub 2]O. None of the waters are coordinated to iron atoms; the former iron complex has an uncoordinated carboxylate arm. Magnetic susceptibility and Moessbauer data confirm that both of the Fe(III) complexes are high spin (S = 5/2) compounds. Enneacoordination about the metal in the crystallographically isostructural series Na[M(DOTA)(H[sub 2]O)][center dot]4H[sub 2]O (M = Gd, Y, Eu) involves the four nitrogen atoms, an oxygen from each carboxyl arm, and one water molecule. Gd(DO3A) has been crystallized as a novel hydrated complex [(Gd(DO3A))Na[sub 2]CO[sub 3]][sub 3][center dot]17H[sub 2]O in which each enneacoordinate Gd atom is coordinated to the four nitrogens and an oxygen from each carboxyl arm of the ligand, as well as two oxygens of the carbonate ion. No water molecule is coordinated to the Gd atoms in the crystal structure. The Gd(DO3A) and Gd(DOTA)-species are more effective water proton relaxation agents than the Fe(III) chelates.

• OSTI ID: 5110644
• Journal Information: Inorganic Chemistry; (United States), Vol. 32:16; ISSN 0020-1669
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
GADOLINIUM COMPLEXES
CRYSTAL STRUCTURE
IRON COMPLEXES
YTTRIUM COMPLEXES
AMINES
CARBOXYLIC ACIDS
CHELATES
CHEMICAL PREPARATION
HYDRATES
MOESSBAUER EFFECT
NUCLEAR MAGNETIC RESONANCE
X-RAY DIFFRACTION
COHERENT SCATTERING
COMPLEXES
DIFFRACTION
MAGNETIC RESONANCE
ORGANIC ACIDS
ORGANIC COMPOUNDS
RARE EARTH COMPLEXES
RESONANCE
SCATTERING
SYNTHESIS
TRANSITION ELEMENT COMPLEXES
400201* - Chemical & Physicochemical Properties