title: Imidazole-based [2 + 1] Re(I)/99mTc(I) complexes as isostructural nuclear and optical probes.
abstract: The synthesis, stability, and photophysical properties of [2 + 1] Re(I)/Tc(I) complexes derived from bipyridine and a series of imidazole derivatives were investigated as a means of identifying complexes suitable for creating targeted isostructural optical/nuclear molecular imaging probes. To prepare the desired complexes, [Re(CO)3(H2O)3]Br was combined with 2,2'-bipyridine (bipy) to give [Re(CO)3(bipy)Br], which in turn was converted to the desired complexes by treatment with functionalized imidazoles, yielding crystal structures of two new Re complexes. The corresponding (99m)Tc complexes [(99m)Tc(CO)3(bipy)(L)](+) (L = imidazole derivatives) were prepared by combining [(99m)Tc(CO)3(bipy)(H2O)]Cl with the same series of ligands and heating at 40 or 60 °C for 30 min. Quantitative transformation to the final products was confirmed in all cases by HPLC, and the nature of the complexes was verified by comparison to the authentic Re standards. Incubation in saline and plasma, and amino acid challenge experiments showed that N-substituted imidazole derivatives, bearing electron donating groups, exhibited superior stability to analogous metal complexes derived from less basic ligands. Imaging studies in mice revealed that with the appropriate choice of monodentate ligand, it is possible to prepare robust [2 + 1] Tc complexes that can be used as the basis for preparing targeted isostructural optical and nuclear probes.
authors: Department of Chemistry and Chemical Biology, McMaster University , 1280 Main Street West, Hamilton, Ontario L8S 4M1, Canada.
authors: Abdolreza
authors: A
authors: Yazdani
authors: Nancy
authors: N
authors: Janzen
authors: Laura
authors: L
authors: Banevicius
authors: Shannon
authors: S
authors: Czorny
authors: John F
authors: JF
authors: Valliant
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid; D018360:Crystallography, X-Ray; D003500:Cyclization; D006801:Humans; D007093:Imidazoles / Q000008:administration & dosage / Q000737:chemistry; D061986:MCF-7 Cells; D051379:Mice; D008807:Mice, Inbred BALB C; D008958:Models, Molecular; D008968:Molecular Conformation; D015335:Molecular Probes / Q000008:administration & dosage / Q000737:chemistry; D009942:Organometallic Compounds / Q000008:administration & dosage / Q000737:chemistry; D012211:Rhenium / Q000008:administration & dosage / Q000737:chemistry; D013667:Technetium / Q000008:administration & dosage / Q000737:chemistry
chemical_list: D007093:Imidazoles; D015335:Molecular Probes; D009942:Organometallic Compounds; D012211:Rhenium; D013667:Technetium; C029899:imidazole