Reactivity of Cyclopentadienes Modified by Bis（3,5- dimethylpyrazol-l-yl）methyl Group to W（CO）5THF

The reactions of the mixture of 1- and 2-[2,2-bis（3,5-dimethylpyrazol-l-yl）-1-phenylethyl]-1,3-cyclopentadiene （bpzpcpH） and mixture of 1- and 2-[2,2-bis（3,5-dimethylpyrazol-l-yl）-I,l-diphenylethyl]-l,3-cyclopentadiene （bpzdpcpH） with W（CO）sTHF have been carried out. The former yields complex （bpzpcpH）W（CO）4, in which the bpzpcpH acts as a k2-（N,N） bidentate ligand, and the cyclopentadiene moiety does not participate in the coordination to the tungsten atom. While the latter gives complex （bpzdpcpH）W（CO）3, in which the cyclopentadiene moiety coordinates to the tungsten atom in η2-fashion instead of general η5-coordinated mode, causing bpzdpcpH to act as a tridentate k3-（π,N,N） ligand,