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[PtI
VCl6]和 K2[PdI
VCl6]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。