Synthesis and properties of Zr–Co heterodinuclear complexes with a bridging bis(cyclopentadienyl) ligand

[(η5-C5H5)ZrCl2(η5-C5H4)CMe2(C5H5)] reacted with Co2(CO)8 to produce a heterodinuclear Zr(IV)–Co(I) complex [(η5-C5H5)ZrCl2(η5-C5H4)CMe2(η5-C5H4)Co(CO)2] (3). Complex 3 underwent oxidative addition of I2 to give [(η5-C5H5)ZrCl2(η5-C5H4)CMe2(η5-C5H4)CoI2(CO)] (4) having Zr(IV) and Co(III) centers. The carbonyl ligand of 4 was easily replaced with P(OMe)3 and PPh3 to afford [(η5-C5H5)ZrCl2(η5-C5H4)CMe2(η5-C5H4)CoI2(L)] (5: L = P(OMe)3, 6: L = PPh3). Structures of 5 and 6 were determined by X-ray crystallography. These Zr–Co heterodinuclear complexes catalyzed polymerization of ethylene and propylene.