Coordination Properties of Klaeui's Tripodal Oxygen Donor toward Zirconium(IV)

The coordination properties of [(η5-C5H5)Co{PR2(O)}3]- (R = OEt (LOEt-), Et (LEt-)) toward Zr(IV) have been investigated and compared to related cyclopentadienyl complexes. Addition of 2 equiv of LOEt- to [ZrCl4(THF)2] yields labile [Zr(LOEt)2Cl2] (2), which undergoes Arbuzov dealkylation to yield a dinuclear, seven-coordinate complex 1. Reaction of 2 with MeLi yields the metathesis product LiLOEt. Addition of 2 equiv of AgOTos to 2 affords octahedral [Zr(LOEt)2](OTos)2 (3). Reaction of [ZrCpCl3] with LOEt- leads to Cp- displacement to give [ZrLOEtCl3] (4). Addition of 2 equiv of LEt- to [ZrCl4(THF)2] yields octahedral [Zr(LEt)2](Cl)2 (5). Compounds 1, 3, 4, and 5 have been characterized by X-ray crystallography.