The reduction of platinum(IV) and palladium(IV) ions by 2,6-pyridinedihydroxamic acid
作者:Darren Griffith、Atish Chopra、Helge Müller-Bunz、Celine J. Marmion
DOI:10.1039/b809584a
日期:——
Reaction of K2[PtIVCl6] and K2[PdIVCl6] with 2,6-pyridinedihydroxamic acid (2,6-pyha) and its disodium salt, 2,6-pyhaNa2, 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-[PtII(2,6-pycaH−1)2]·2H2O and trans-[PdII(2,6-pycaH−1)2]·2H2O 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-pyhaNa2·8H2O, trans-[PtII(2,6-pycaH−1)2]·2H2O and trans-[PdII(2,6-pycaH−1)2]·2H2O 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.
K2[PtIVCl6]和 K2[PdIVCl6]与 2,6-吡啶二羟肟酸(2,6-pyha)及其二钠盐 2,6-pyhaNa2 反应,得到的不是所需的铂(IV)和钯(IV)2,6-吡啶二羟肟配合物,而是铂(II)和钯(II)2,6-吡啶二羧酸配合物,即反式-[PtII(2,6-pycaH-1)2]-2H而是铂(II)和钯(II)2,6-吡啶二甲酸配合物,分别为反式-[PtII(2,6-pycaH-1)2]-2H2O 和反式-[PdII(2,6-pycaH-1)2]-2H2O(2,6-pyca = 2,6-吡啶二甲酸)。因此,在铂(IV)和钯(IV)的存在下,二羟肟酸被冒险水解为相应的二羧酸,而铂(IV)和钯(IV)则被原位还原为铂(II)和钯(II)。报告了 2,6-pyha、2,6-pyhaNa2-8H2O、反式[PtII(2,6-pycaH-1)2]-2H2O 和反式[PdII(2,6-pycaH-1)2]-2H2O 的 X 射线晶体结构,以及金属辅助水解二羟肟酸并将 Pt(IV) 和 Pd(IV) 分别还原为 Pt(II) 和 Pd(II) 的可能机制。