Regioselective addition of bifunctional oximehydroxamic acid by the hydroxamic group to Pt(IV)-coordinated nitriles

The metal-mediated coupling between the nitriles RCN in the platinum(IV) complexes trans-[PtCl4(RCN)2] (RMe, Et, CH2Ph, Ph), cis/trans-[PtCl4(MeCN)(Me2SO)] and the newly synthesized bifunctional oximehydroxamic acid, viz. N,2-dihydroxy-5-(1-hydroxyiminoethyl)benzamide, proceeds smoothly in CH2Cl2 at 40–45 °C to accomplish the new metallaligands HNC(R)ONHC(O)C6H3(2-OH)(5-C(Me)NOH) with pendant oxime functionalities due to the regioselective addition of the reagent via its hydroxamic groups. The obtained iminoligands exist in hydroxamic/hydroximic tautomeric equilibrium in solution. The structures of the isolated compounds are based on elemental analyses (C, H, N), IR, 1D 1H, 13C{1H}, and 2D NMR correlation experiments, i.e. 1H,13C-COSY, 1H,13C long range COSY, 1H,15N-COSY, and 1H,15N long range COSY.