Preparation of some cyclopentadienyl platinum (IV) complexes

Abstract

Two routes to the synthesis of (η5-C5H5)PtR1R2R3, where R1, R2, and R3 are not all CH3, were explored. The complexes [PtR1R2R3X]4, where R1 = R2 = CH3, R3 = C(O)CH3, C2H5; R1 = R2 = C2H5, R3 = CH3, C(O)CH3; R1 = CH3, R2 = C2H5, R3 = C(O)CH3; X = Cl or I, were prepared and treated with TlCp to give (η5-C5H5)PtR1R2R3. The latter are the first polyfunctionalized cyclopentadienyl platinum(IV) complexes. Conformational isomerism about the platinum to acetyl–carbon bond was detected by infrared spectroscopy. The cleavage of a Pt—CH3 or Pt—C(O)CH3 bond in CpPt(CH3)2R using the reagents HCl, HgCl2, or I2 was not successful; the appropriate [Pt(CH3),RX]4 being isolated instead. The chiral nature of (η5-C5H5)Pt(CH3)(C2H5)[C(O)CH3] is noted.