Platinum(IV) complexes of primary amines via oxidative addition

• Square planar Pt(II) complexes and their octahedral Pt(IV) derivatives.
• Iodination and bromination of cycloplatinated primary amines.
• cis oxidative addition.
• Structural characterization of potentially cytostatic compounds.

Oxidative addition allows to synthesize the first cycloplatinated primary amines in which the platinum adopts oxidation state +IV: Square planar organoplatinum(II) complexes can be converted with elementary diiodine and dibromine to the corresponding pseudo-octahedral Pt(IV) derivatives. The reaction may be monitored with the help of NMR spectroscopy and five of the target products have been characterized by single crystal X-ray diffraction. Two of these Pt(IV) complexes provide structural evidence for cis addition of the halogen and for the pronounced trans effect of the Pt–C bond. The latter is also reflected in a substitution reaction promoted by AgBF4: The halide substituent trans to the C in the coordination sphere can be selectively replaced by the pseudohalide cyanate. In the absence of a suitable silver salt, the pseudo-octahedral Pt(IV) complexes are inert in substitution reactions.

Square planar divalent complexes of cycloplatinated primary amines can be oxidized in presence of iodine, bromine and methyliodide to octahedral Pt(IV) derivatives.Figure optionsDownload as PowerPoint slide