Synthesis, characterization and decomposition behavior of novel acyl(hydrido)platinum(IV) complexes

The platina-β-diketone [Pt2{(COMe)2H}2(μ-Cl)2] (1) easily reacts with chelating nitrogen ligands NN (2,2′-bipyridine (bpy) and 1,10-phenanthroline (phen) derivatives) to form novel acyl(hydrido)platinum(IV) complexes [Pt(COMe)2Cl(H)(NN)] (NN=bpy 2a, 6-n-Bubpy 2b, 6-sec-Bubpy 2c, 6-Phbpy 2d, 4,4′-Me2bpy 2e, 4,4′-tert-Bu2bpy 2f, 4,4′-tert-Bu2-6-n-Bubpy 2g, phen 2h, 5-Mephen 2i, 4-Mephen 2j, 5-Phphen 2k) with good to excellent yields (55–95%). The identities of 2a–k were determined by microanalysis, NMR (1H, 13C) and IR spectroscopies. The crystal structure of [Pt(COMe)2Cl(H)(4,4′-tert-Bu2-6-n-Bubpy)] (2g) has been determined. The PtH bond distance was found to be 1.79(2) Å. Complexes 2a–k show an astonishing thermal stability in the solid state (Tdec 140–180°C) and decompose with cleavage of acetaldehyde to form acylplatinum(II) complexes [Pt(COMe)Cl(NN)] (3). For 2f it was shown that in boiling solvents (chloroform, methylene chloride, acetone, methanol, toluene, dimethyl sulfoxide, tetrahydrofuran) this decomposition reaction proceeds as well. In boiling chlorinated solvents [PtCl2(NN)] (4) is formed as a side product.