title: The reduction of platinum(IV) and palladium(IV) ions by 2,6-pyridinedihydroxamic acid.
abstract: Reaction of K(2)[Pt(IV)Cl(6)] and K(2)[Pd(IV)Cl(6)] with 2,6-pyridinedihydroxamic acid (2,6-pyha) and its disodium salt, 2,6-pyhaNa(2), yielded not the desired Pt(IV) and Pd(IV) 2,6-pyridinedihydroxamato complexes, but rather the Pt(II) and Pd(II) 2,6-pyridinedicarboxylato complexes, trans-[Pt(II)(2,6-pyca(H-1))(2)].2H(2)O and trans-[Pd(II)(2,6-pyca(H-1))(2)].2H(2)O respectively (2,6-pyca = 2,6-pyridinedicarboxylic acid). Thus in the presence of Pt(IV) and Pd(IV), the dihydroxamic acid was adventitiously hydrolysed to the corresponding dicarboxylic acid and Pt(IV) and Pd(IV) reduced to Pt(II) and Pd(II) in situ. The X-ray crystal structures of 2,6-pyha, 2,6-pyhaNa(2).8H(2)O, trans-[Pt(II)(2,6-pyca(H-1))(2)].2H(2)O and trans-[Pd(II)(2,6-pyca(H-1))(2)].2H(2)O are reported, together with a possible mechanism for the metal-assisted hydrolysis of the dihydroxamic acid and reduction of Pt(IV) and Pd(IV) to Pt(II) and Pd(II) respectively.
authors.affiliation: Centre for Synthesis & Chemical Biology, Department of Pharmaceutical & Medicinal Chemistry, Royal College of Surgeons in Ireland, Dublin 2, Ireland. dgriffith@rcsi.ie
authors.forename: Darren
authors.initials: D
authors.lastname: Griffith
authors.forename: Atish
authors.initials: A
authors.lastname: Chopra
authors.forename: Helge
authors.initials: H
authors.lastname: Müller-Bunz
authors.forename: Celine J
authors.initials: CJ
authors.lastname: Marmion
mesh_terms: D018360:Crystallography, X-Ray; D006877:Hydroxamic Acids / Q000138:chemical synthesis / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry; D010084:Oxidation-Reduction; D010165:Palladium / Q000737:chemistry*; D010984:Platinum / Q000737:chemistry*; D012492:Salts / Q000737:chemistry; D012964:Sodium / Q000737:chemistry; D012995:Solubility; D014867:Water / Q000737:chemistry
chemical_list: D006877:Hydroxamic Acids; D009942:Organometallic Compounds; D012492:Salts; D014867:Water; C024588:2,6-pyridinedicarbohydroxamic acid; D010984:Platinum; D010165:Palladium; D012964:Sodium