title: Oxorhenium phosphinophenolato complexes with model peptide fragments: synthesis, characterization, and stability considerations.
abstract: The synthesis and characterization of a series of mixed-ligand oxorhenium(V) complexes containing the o-diphenylphosphinophenolato ligand (HL) and model peptide fragments acting as the tridentate coligand are reported. Thus, by reacting equimolar amounts of tiopronin, Gly-Gly, Gly-L-Phe, or glutathione (GSH) peptides on the [(n-C4H9)4N][ReOCl3(L)] precursor in refluxing MeCN/MeOH or aqueous MeCN/MeOH mixtures, the following complexes were obtained: ReO([SC(CH3)CONCH2COO][L])[(n-C4H9)4N], 1, ReO([H2NCH2CONCH2COO][L]), 2, ReO)[H2NCH2CONCH(CH2C6H5)COO][L]), 3, and ReO([SCH2CH(NHCOCH2CH2CHNH2COOH)CONCH2COO][L])Na, 4. The compounds are closed-shell 18-electron oxorhenium species adopting a distorted octahedral geometry, as demonstrated by classical spectroscopical methods including multinuclear NMR. X-ray diffraction analyses for 1 and 2 are also reported. By comparative stability studies of complexes 1-3 against excess GSH it was shown that complex 3 containing the bulky C6H5CH2 substituent adjacent to the coordinated carboxylate group of Phe is the most stable complex.
authors.affiliation: Institute of Radioisotopes-Radiodiagnostic Products, National Centre for Scientific Research "Demokritos", 15310 Ag. Paraskevi, Athens, Greece.
authors.forename: B
authors.initials: B
authors.lastname: Nock
authors.forename: T
authors.initials: T
authors.lastname: Maina
authors.forename: F
authors.initials: F
authors.lastname: Tisato
authors.forename: C P
authors.initials: CP
authors.lastname: Raptopoulou
authors.forename: A
authors.initials: A
authors.lastname: Terzis
authors.forename: E
authors.initials: E
authors.lastname: Chiotellis
mesh_terms: D002614:Chelating Agents / Q000138:chemical synthesis / Q000737:chemistry*; D018360:Crystallography, X-Ray; D005978:Glutathione / Q000037:antagonists & inhibitors; D062385:Hydroxybenzoates / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000737:chemistry*; D012211:Rhenium / Q000737:chemistry*
chemical_list: D002614:Chelating Agents; D062385:Hydroxybenzoates; D010446:Peptide Fragments; D012211:Rhenium; D005978:Glutathione; C017616:phenolic acid