Reactivity of Cyclopentadienes Modified by Bis(3,5‐dimethylpyrazol‐1‐yl)methyl Group to W(CO) 5 THF

The reactions of the mixture of 1‐ and 2‐[2,2‐bis(3,5‐dimethylpyrazol‐1‐yl)‐1‐phenylethyl]‐1,3‐cyclopentadiene (bpzpcpH) and mixture of 1‐ and 2‐[2,2‐bis(3,5‐dimethylpyrazol‐1‐yl)‐1,1‐diphenylethyl]‐1,3‐cyclopentadiene (bpzdpcpH) with W(CO) 5 THF have been carried out. The former yields complex (bpzpcpH)W(CO) 4 , in which the bpzpcpH acts as a κ 2 ‐(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 η 2 ‐fashion instead of general η 5 ‐coordinated mode, causing bpzdpcpH to act as a tridentate κ 3 ‐(π,N,N) ligand.