The first observation and structural characterization of (formamide)platinum(IV) complexes

The reaction of trans-[PtCl4 (EtCN)(2)] and two equivalents of the formamid es RR'NCHO (R/R' = Me/Me, Me/H, tBu/H) in CH2Cl2 led to the formation of th e compounds cis-[PtCl4{(O=)-CHNRR'}(2)], two of which (R/R' = Me/H, tBu/H) were characterized by X-ray single-crystal diffractometry, as well as by el emental analysis, FAB(+)-MS, and IR, H-1, C-13 and Pt-195 NMR spectroscopy (including NOE, HMQC and INEPT experiments). The X-ray structures and IR sp ectroscopic data indicate the coordination of the formamides through the O atom and significant contribution of the bipolar structure O--C(H)=+NHR in the resonance hybrid of the ligands. The complexes cis-[PtCl4[(O=)CHNRR'](2 )] represent the first example of (formamide)Pt-IV species and also a rare case of platinum(IV) complexes with neutral O-donor ligands.