Dimeric W3SO3 cluster complexes: synthesis, characterization, and potential applications as X-ray contrast agents.
Our continued research on the use of heavy metal cluster complexes as a new class of X-ray contrast agents in medical diagnostic imaging is described. A series of 2:3 cluster-ligand complexes, [(W(IV)3SO3)2L3]4- (L = linear polyaminopolycarboxylate ligands), were isolated from the reaction of aqua ion [W(IV)3SO3(H2O)9]4- (prepared in large quantities through an improved literature process) with respective ligands in refluxing DMF. The salts of [(W(IV)3SO3)2L3]4- complex anions were fully characterized using routine techniques such as elemental analysis, MS, HPLC, UV-vis, IR, and NMR. The solid structures of two complex anions, [(W(IV)3SO3)2(PDTA)3]4- and [(W(IV)3SO3)2(HO-PDTA)3]4-, were determined by X-ray crystallography. They are the first examples wherein two W(IV)3SO3 clusters are complexed and linked by three ligands that contain two terminal iminodiacetate (bis-IDA) groups. Complexation of the unstable aqua ion [W(IV)3SO3(H2O)9]4- with ligands has imparted desired biological compatibility to the tungsten metal cluster. These complexes are stable and highly soluble in H2O. The potential utility of such tungsten cluster complexes as X-ray contrast agents was evaluated in both in vitro and in vivo animal studies. In addition, the syntheses of several new linear polyaminopolycarboxylate ligands used in this study are reported.
Torsten Almén Research Center, Nycomed Amersham Imaging, 466 Devon Park Drive, Wayne, Pennsylvania 19087, USA.
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Yu
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Droege
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Downey
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Segal
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Newcomb
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Sanderson
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Crofts
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Suravajjala
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Bacon
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Earley
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Delecki
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Watson
D000818:Animals; D003287:Contrast Media / Q000138:chemical synthesis* / Q000737:chemistry / Q000627:therapeutic use*; D018360:Crystallography, X-Ray; D019281:Dimerization; D066298:In Vitro Techniques; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D015394:Molecular Structure; D051381:Rats; D017973:Tungsten Compounds / Q000138:chemical synthesis* / Q000737:chemistry / Q000627:therapeutic use*; D014965:X-Rays
D003287:Contrast Media; D017973:Tungsten Compounds