title: Pyridine-tert-nitrogen-phenol ligands: N,N,O-Type tripodal chelates for the [M(CO)3]+ core (M = Re, Tc).
abstract: The design rationale, synthesis, and preliminary radiolabeling evaluation of new N,N,O-type pyridyl- tert-nitrogen-phenol ligands for the [M(CO) 3] (+) core, where M = (99m)Tc or Re, are described. The capability of the ligands to bind this technetium core is initially demonstrated by using the cold surrogate [Re(CO) 3] (+). NMR studies of the relevant rhenium tricarbonyl complexes indicate the formation of either a monomeric or a possible dimeric complex with each phenolic O atom bridging between two metal centers. Labeling with [ (99m)Tc(CO) 3] (+) provided further insight into the differences in complex formation on the dilute, no carrier added, level compared to the macroscopic scale at which the Re (I) counterparts were made. These new tridentate, monoanionic ligands are competent chelates in binding the [ (99m)Tc(CO) 3] (+) core because radiolabeling yields ranged from 85 to 99% and the resulting complexes were stable to cysteine and histidine challenges for as long as 24 h.
authors.affiliation: Medicinal Inorganic Chemistry Group, Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada.
authors.forename: Nathaniel C
authors.initials: NC
authors.lastname: Lim
authors.forename: Charles B
authors.initials: CB
authors.lastname: Ewart
authors.forename: Meryn L
authors.initials: ML
authors.lastname: Bowen
authors.forename: Cara L
authors.initials: CL
authors.lastname: Ferreira
authors.forename: Cheri A
authors.initials: CA
authors.lastname: Barta
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Adam
authors.forename: Chris
authors.initials: C
authors.lastname: Orvig
mesh_terms: D001665:Binding Sites; D002614:Chelating Agents / Q000737:chemistry*; D018360:Crystallography, X-Ray; D003545:Cysteine / Q000737:chemistry; D019281:Dimerization; D006639:Histidine / Q000737:chemistry; D007553:Isotope Labeling; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D009584:Nitrogen / Q000737:chemistry; D009942:Organometallic Compounds / Q000138:chemical synthesis*; D010100:Oxygen / Q000737:chemistry; D019800:Phenol / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry*; D019275:Radiopharmaceuticals / Q000138:chemical synthesis*; D012211:Rhenium / Q000737:chemistry*; D013667:Technetium / Q000737:chemistry*; D013997:Time Factors
chemical_list: D002614:Chelating Agents; D008024:Ligands; D009942:Organometallic Compounds; D011725:Pyridines; D019275:Radiopharmaceuticals; D019800:Phenol; D006639:Histidine; D012211:Rhenium; D013667:Technetium; D003545:Cysteine; D009584:Nitrogen; C023666:pyridine; D010100:Oxygen