Oxidative addition-reductive elimination reactions of mon- and bis(aryl)platinum(II) complexes with two amino ligands in fixed trans positions. X-ray crystal structures of (2,6-bis[{dimethylamino}methyl]phenyl)(4-tolyl)Pt(IV) diiodide and (2,6-bis[{dimethyl-amino}methyl]phenyl)Pt(IV) trichloride