The reduction of platinum(IV) and palladium(IV) ions by 2,6-pyridinedihydroxamic acid?

Dalton Transactions Pub Date: 2008-10-23 DOI: 10.1039/B809584A

Abstract

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.

Graphical abstract: The reduction of platinum(IV) and palladium(IV) ions by 2,6-pyridinedihydroxamic acid
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