title: Reactivity of the [M(PS)2](+) building block (M = Re(III) and (99m)Tc(III); PS = phosphinothiolate) toward isopropylxanthate and pyridine-2-thiolate.
abstract: The coordination properties of isopropylxanthate (i-Pr-Tiox) and pyridine-2-thiolate (PyS) toward the [M(PS)2](+) moiety (M = Re and (99m)Tc; PS = phosphinothiolate) were investigated. Synthesis and full characterization of [Re(PS2)2(i-Pr-Tiox)] (Re1), [Re(PSiso)2(i-Pr-Tiox)] (Re2), [Re(PS2)2(PyS)] (Re3), and [Re(PSiso)2(PyS)] (Re4), where PS2 = 2-(diphenylphosphino)ethanethiolate and PSiso = 2-(diisopropylphosphino)ethanethiolate, and the structural X-ray analysis of complex Re3 were carried out. (99m)Tc analogues of complexes Re2 ((99m)Tc2) and Re4 ((99m)Tc4) were obtained in high radiochemical yield following a simple one-pot procedure. The chemical identity of the radiolabeled compounds was confirmed by chromatographic comparison with the corresponding rhenium complexes and by dual radio/UV HPLC analysis combined with ESI(+)-MS of (99g/99m)Tc complexes prepared in carrier-added conditions. The two radiolabeled complexes were stable with regard to trans chelation with cysteine, glutathione, and ethylenediaminotetraacetic acid and in rat and human sera. This study highlights the substitution-inert metal-fragment behavior of the [M(PS)2](+) framework, which reacts with suitable bidentate coligands to form stable hexacoordinated asymmetrical complexes. This feature makes it a promising platform on which to develop a new class of Re/Tc complexes that are potentially useful in radiopharmaceutical applications.
authors.affiliation: Dipartimento di Scienze Chirurgiche, Oncologiche e Gastroenterologiche, Università degli Studi di Padova , via Gattamelata 64, 35138 Padua, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Salvarese
authors.forename: Alessandro
authors.initials: A
authors.lastname: Dolmella
authors.forename: Fiorenzo
authors.initials: F
authors.lastname: Refosco
authors.forename: Cristina
authors.initials: C
authors.lastname: Bolzati
mesh_terms: D018360:Crystallography, X-Ray; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010720:Phosphines / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry*; D012211:Rhenium / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013667:Technetium / Q000737:chemistry*; D013871:Thiones / Q000737:chemistry*
chemical_list: D009942:Organometallic Compounds; D010720:Phosphines; D011725:Pyridines; D013438:Sulfhydryl Compounds; D013871:Thiones; C118698:propylxanthate; C000602191:pyridine-2-thiolate; D012211:Rhenium; D013667:Technetium