473907-48-1Relevant academic research and scientific papers
Synthesis, characterization, properties and structures of rhenium(II), -(III), and -(V) complexes containing amino acids conjugated with a 2-aminothiazole ligand
Lazzaro, Antonio,Vertuani, Gianni,Bergamini, Paola,Mantovani, Nicoletta,Marchi, Andrea,Marvelli, Lorenza,Rossi, Roberto,Bertolasi, Valerio,Ferretti, Valeria
, p. 2843 - 2851 (2002)
The one-step reaction of KReO4 with benzoylhydrazine in the presence of concentrated HCl and PPh3 afforded [ReV(NNC(Ph)O)(PPh3)2Cl2]1 which was converted with carbon monoxide into the dinitrogen Re(I) complex [ReN2(CO)2(PPh3)2Cl]2 in good yield. A new class of ligands, of general formula HLn (n = 1-5), was obtained by conjugation of N-protected amino acids and benzoic acid with 2-aminothiazole. Complex 2 reacted with HLn to give neutral Re(II) chelate complexes [Re(Ln)(CO)(PPh3)2Cl]5-9 (n = 1-5), by substitution of N2 and CO groups. The molecular structure of complex 9 was determined by X-ray diffraction. When reactions between [Re(NNC-(Ph)O)(PPh3)2Cl2]1 and HLn (n = 2, 5) were carried out in different stoichiometric ratios, neutral mono- and di-substituted Re(III) organodiazenido complexes [Re(NNCOPh)(L2,5)(PPh3)2Cl]10, 11 and [Re(NNCOPh)(L5)2-(PPh3)]12 were obtained. In these complexes the organodiazenido Re-N-N moiety adopts a linear conformation, as has been authenticated by X-ray diffraction analysis for 11 and12. Treatment of Re(I) dinitrogen precursors [ReN2(P)4Cl] (P= PMe2Ph, 3 and PMePh2,4) with ligands resulted in interesting dinuclear oxo-(μ-oxo)-Re(V) species [Re2(O)3(Ln)2(P)2] (P = PMe2Ph, n = 1, 13; n = 2, 14; n = 4, 15. P = PMePh2, n = 2, 16). Suitable crystals for an X-ray analysis have been obtained for complex 14. The structure represents one of the few cases where, for steric reasons, the Re-O-Re bridging unit is not linear but rather bent. All the compounds have been characterized by elemental analyses, IR and NMR spectroscopy. The Re(II) complexes 5-7 and9 were further characterized by electrochemical measurements.
