PLATINUM(IV) ORGANOMETALLICS .1. SYNTHESES OF 1,2-DIAMINE-CIS-BIS(PENTAFLUOROPHENYL)PLATINUM(IV) COMPLEXES AND THE X-RAY CRYSTAL-STRUCTURE OF THE N-BUTANOATO DERIVATIVE

The complex Pt(C6F5)(2)(OH)(2)(en) (en = ethane-1,2-diamine) has been prepared by oxidation of Pt(C6F5)(2)(en) with hydrogen peroxide in ace tone. Treatment of the platinum(IV) complex with acid anhydrides, (RCO )(2)O (R = Me, Et, Pr-n, or Pr-i), in ether yields cis, trans-Pt(C6F5) (2)(O(2)CR)(2)(en) complexes. The stereochemistry was established by a n X-ray diffraction study of Pt(C6F5)(2)((O2CPr)-Pr-n)(2)(en), which h as an octahedral arrangement involving trans unidentate butanoate liga nds and cis-C6F5 groups, and by spectroscopic similarities between the complexes. There is hydrogen bonding between uncoordinated carboxyl o xygens and NH groups, and between one ortho-fluorine of each C6F5 grou p and an NH group. The F-19 NMR spectra show five fluorine resonances at -50 degrees C, indicative of unsymmetrical C6F5 groups with restric ted rotation, and this is consistent with features of the solid state structure of cis, trans-Pt(C6F5)(2)((O2CPr)-Pr-n)(2)(en). Preliminary examination of the biological activity of the complexes against L1210 and L1210/DDP mouse leukemia cells in culture has been made.