title: Rhenium diazenide ternary complexes with dithiocarbamate ligands: towards new rhenium radiopharmaceuticals.
abstract: The reaction of the mono-diazenide core, [ReCl2(NNC6H(4)-4-OCH3)(NCCH3)(PPh3)2], with four equivalents of the sodium or potassium salts of dithiocarbamate (dtc) ligands gives neutral complexes of the formula [Re(NNC6H(4)-4-OCH3)(dtc)2(PPh3)]. It is possible to use a wide range of dithiocarbamate ligands (S2CNRR') with a variety of R groups (R=R'=methyl, phenyl or ethyl; R=methyl, R'=phenyl and R=R'=morpholino). Substitution reactions with dtc ligands on the mono-diazenide derived from 2-hydrazinopyridine, [ReCl2(NNC5H4N)(PPh3)2, give the analogous complexes, [Re(NNC6H5N)(dtc)2(PPh3)]. The new complexes have been characterised by a combination of NMR spectroscopy, mass spectrometry and X-ray crystallography. Cyclic voltammetry measurements in dimethyl formamide show that the rhenium diazenido-dtc complexes undergo a quasi-reversible oxidation tentatively assigned to a ReIII/ReIV oxidation. Since the parent complex, [ReCl2(NNC6H(4)-4-R)(NCCH3)(PPh3)2] can be prepared directly from perrhenate and readily derivatised with dtc ligands these complexes have potential relevance to the development of new therapeutic rhenium radiopharmaceuticals.
authors.affiliation: Chemical Crystallography, University of Oxford, 12 Mansfield Road, Oxford, UK OX1 3TA.
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Cowley
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Dilworth
authors.forename: Paul S
authors.initials: PS
authors.lastname: Donnelly
authors.forename: Susan J
authors.initials: SJ
authors.lastname: Ross
mesh_terms: D018360:Crystallography, X-Ray; D006834:Hydrazines / Q000737:chemistry*; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008958:Models, Molecular; D008968:Molecular Conformation; D009941:Organomercury Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D019275:Radiopharmaceuticals / Q000138:chemical synthesis* / Q000737:chemistry; D012211:Rhenium / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013237:Stereoisomerism; D013859:Thiocarbamates / Q000737:chemistry*
chemical_list: D006834:Hydrazines; D008024:Ligands; D009941:Organomercury Compounds; D019275:Radiopharmaceuticals; D013859:Thiocarbamates; D012211:Rhenium