METAL INSERTION INTO A CH BOND AS A ROUTE TO THE HETEROBIMETALLIC MU-METHYLIDENE COMPLEX C5H5(CO)2RE(MU-CH2)PT(PPH3)2

The reaction of C5H5(CO)2Re(CH3)-Li+.THF (5) with (Ph3P)3Pt[(E)-C(CH3)=CHCH3]+CF3SO3- (3E) in an attempt to prepare the heterobimetallic complex C5H5(CO)2(CH3)RePt[(E)-C(CH3)=CHCH3](PPh3)2 (B) led to the formation of the new heterobimetallic mu-methylene complex C5H5(CO)2Re(mu-CH2)Pt(PPh3)2 (4), which was characterized by X-ray crystallography. A mechanism involving initial generation of intermediate B followed by insertion of Pt into a C-H bond and reductive elimination is suggested. The related substituted alkylidene complexes C5H5(CO)2Re[mu-CH(E-CH3C=CHCH3)]Pt(PPh3)2 (9) and C5H5(CO)2Re(mu-CHCH3)Pt(PPh3)2 (11) were prepared from Pt(C2H4)(PPh3)2 and the appropriate rhenium alkylidene complexes C5H5(CO)2Re=CHR.