The reaction of pyrrole-2-carboxaldehyde with cyclopentadiene in MeOH and pyrrolidine gives a fulvene compound, (Cp)CH(Py) $(Cp= C_5H_5, Py=C_4H_4N)$ $\textbf{1a}$. A pyrrole ligand, (Cp)$CH_2$(Py) $(\textbf{1b})$, has been prepared from the reaction of $\textbf{1a}$ with $LiAlH_4$ in THF. The reaction of \textbf{1b} with Ti(NMe$_2$)$_4$ affords a bisamido complex, [(Cp)CH$_2$(Py)]Ti(NMe$_2$)$_2$ $\textbf{1c}$.
The methods of preparation of $(t-BuCp)CH_2(Py)$ $(\textbf{2b})$ and $(Ind)CH_2(Py)$ $\textbf{3b}$ from t-butylcyclopentadiene and indene, respectively, are similar to that of $\textbf{1a}$. The reaction of $\textbf{2b}$ or $\textbf{3b}$ with Ti(NMe$_2$)$_4$ produces bisamidotitanium(IV) complexes, $[(t-BuCp)CH_2 (Py)]$ $(NMe_2)_2$ (\textbf{2c}) and $[(Ind)CH_2(Py)]$ $Ti(NMe_2)_2$ (\textbf{3c}), respectively.
The structure of $\textbf{1c}$ has been determined by a single-crylstal X-ray diffraction study. The titanium atom is coordinated to the cyclopentadiene in an $\eta^5$ -fashion. This molecule has no crystallographic mirror plane in the solid state. The short Ti-NMe$_2$ bond distances (1.887 and 1.898A) and the planar geometries for the nitrogen atoms indicate an $sp^2$ -hybridization, with the nitrogen lone pairs used in the $N(p_\pi)\toM(d_\pi)$ interactions. The electron rich Ti metal induces the pyrrole group to behave as one electron donor, which is indicated by a long Ti-Py bond distance (2.039 Å).
