INOR 668 |
| To understand the coordination chemistry of DO3A-xy-TPP (1-[a-(triphenylphosphonium)methyl-4-benzyl)]-1,4,7,10-tetraazacyclododecane-4,7,10-triacetic acid) with diagnostically important metal ions, its In(III), Ga(III) and Mn(II) complexes were synthesized and characterized by spectroscopic methods (IR, ESI-MS, and NMR), elemental analysis and X-ray crystallography. Both In(DO3A-xy-TPP)+ and Ga(DO3A-xy-TPP)+ were isolated as cations while Mn(DO3A-xy-TPP) was obtained in its Zwitterion form. The solid state structure of In(DO3A-xy-TPP)+ is very similar to that of Mn(DO3A-xy-TPP) with DO3A as a heptadentate ligand in bonding to In(III) and Mn(II) in the capped octahedron geometry. Due to smaller size of Ga(III), the coordinated DO3A in Ga(DO3A-xy-TPP)+ is hexadentate with four amine-N and two carboxylate-O atoms bonding to Ga(III). The coordination geometry of Ga(DO3A-xy-TPP)+ is best described as distorted octahedron. 1H NMR data of In(DO3A-xy-TPP)+ showed that the coordinated DO3A in In(DO3A-xy-TPP)+ is fluxional in aqueous solution; but there is no dissociation of the three carboxylic groups. This is consistent with the high solution stability of 111In(DO3A-xy-TPP)+. 1H NMR data of Ga(DO3A-xy-TPP)+ showed that one carboxylate group in the coordinated DO3A was deprotonated while there is no dissociation of the other two opposite carboxylate group which is consistent with the solid state structure.
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Characterization and Applications of Coordination Compounds
7:00 PM-10:00 PM, Tuesday, August 21, 2007 BCEC -- Exhibit Hall - B2, Poster
Division of Inorganic Chemistry |
