Coordination chemistry of bis-thiohydroxamic acids: synthesis and characterization of their lead(II) complexes and stability constant determination

Autor: Stefan Rupprecht, James McCormick, Klaus Langemann, Thomas Lügger, Kenneth N. Raymond
Rok vydání: 1996
Předmět:
Zdroj: Inorganica Chimica Acta. 243:79-90
ISSN: 0020-1693
DOI: 10.1016/0020-1693(95)04894-4
Popis: The synthesis of a number of bis-thiohydroxamic acids with linking groups of varying lengths and rigidities are reported as potential Pb2+-specific chelating agents. In contrast to the predictions of CaChe® and CAVAET© molecular mechanics programs, the most rigid ligands of this series do not form discreet Pb2+ complexes, but rather polymers. The less rigid aliphatic linking groups do form discreet complexes with Pb2+, which are characterized by 1H, 13C and 207Pb NMR. The synthesis and X-ray crystal structure of the first water-soluble bis-thiohydroxamic acid, N-hydroxy-3{2-[2-(hydroxy-methyl-thio-carbamoyl)ethoxy]ethoxy}-N-methy thiopropionamide (11) is described. The structure of 11 shows that the thiohydroxamic groups in the molecule adopt a Z configuration and form weak intermolecular hydrogen bonds resulting in a chain structure in the solid state. The formation constant of 11 with Pb2+ in 50% methanol/water is found to be 1012.53.
Databáze: OpenAIRE