The thermodynamic selectivity for Gd(3+) relative to Ca(2+), Zn(2+), and Fe(3+) of two ligands of potential interest as magnetic resonance imaging (MRI) contrast agents has been determined by NMR spectroscopy and potentiometric and spectrophotometric titration. The two hexadentate ligands TREN-6-Me-3,2-HOPO (H(3)L2) and TREN-bisHOPO-TAM-EA (H(4)L3) incorporate 2,3-dihydroxypyridonate and 2,3-di...

We report the syntheses of six new salts of the iron(III) complexes of four hexadentate Schiff bases of the saltrien-type derived from 1,8-diamino-3,6-diazaoctane and 2 equiv. of the appropriate salicylaldehyde derivative. Three of these new compounds undergo gradual spin-transitions centred between 155-204 K in the solid state, that proceed to 35-50% completeness. One of the other compounds re...

The effect of bidentate 3-hydroxypyridin-4-one (HPO) iron chelators on cell cycle arrest with subsequent cycle synchronization has been compared with that of the hexadentate desferrioxamine (DFO) in K562 and Daudi cells. The relationships between chelator concentration and inhibition of growth, DNA synthesis and ribonucleotide reductase, and phase of cell cycle arrest have also been explored. H...

Copper(II) complexes of hexadentate ethylenediaminetetracarboxylic acid type ligands H(4)eda3p and H(4)eddadp (H(4)eda3p = ethylenediamine-N-acetic-N,N',N'-tri-3-propionic acid; H(4)eddadp = ethylenediamine-N,N'-diacetic-N,N'-di-3-propionic acid) have been prepared. An octahedral trans(O(6)) geometry (two propionate ligands coordinated in axial positions) has been established crystallographical...

The synthesis of the new potentially hexadentate ligands N,N'-bis(2,2'-bipyridin-6-ylmethyl)butane-1,4-diamine (bmbu), N,N'-bis(2,2'-bipyridin-6-ylmethyl)pentane-1,5-diamine (bmpt) and N,N'-bis(2,2'-bipyridin-6-ylmethyl)octane-1,8-diamine (bmot) from the condensation of 2,2'-bipyridine-6-carbaldehyde with the appropriate diamine (butane-1,4-diamine, pentane-1,5-diamine and octane-1,8-diamine, r...

Reprint requests to Dr. B. Kersting. E-mail: [email protected] Z. Naturforsch. 55 b, 1179-1187 (2000); received August 17, 2000 Cobalt Complexes, Amine-Thiolate Ligands, Sulfinate Complexes The reactivity of Co111 amine-thiolate complexes with terminal and bridging thiolate func­ tions towards oxidizing agents has been investigated. The mononuclear Co N3S3 complex [Coni(L1)] (2)...

PURPOSE To identify the most effective multidentate 1,2-HOPO and Me-3,2-HOPO ligands for chelation of Pu(IV) in vivo. MATERIALS AND METHODS Two sets of ligands with four identical backbones were prepared containing two, three or four bidentate 1,2-HOPO or Me-3,2-HOPO groups, and 3,4,3-LI(1,2-HOPO) was resynthesized in a higher yielding procedure. They were evaluated in mouse for acute toxicit...