Decamethyltitanocene dichloride explained

Decamethyltitanocene dichloride is an organotitanium compound with the formula Cp*₂TiCl₂ (where Cp* is C₅(CH₃)₅, derived from pentamethylcyclopentadiene). It is a red solid that is soluble in nonpolar organic solvents. The complex has been the subject of extensive research. It is a precursor to many organotitanium complexes. The complex is related to titanocene dichloride, which lacks the methyl groups.

Synthesis and reactions

The complex is prepared by the reaction of titanium tetrachloride with LiCp*. An intermediate in this synthesis is (pentamethylcyclopentadienyl)titanium trichloride.

Reduction of Cp*₂TiCl₂ in the presence of ethylene gives the adduct Cp*₂Ti(C₂H₄).^[1] The analogous Cp compound has not been prepared, a contrast that highlights the advantages of the Cp* ligand. This pentamethylcyclopentadienyl (Cp*) species undergoes many reactions such as cycloadditions of alkynes.^[2]

The dicarbonyl complex Cp*₂Ti(CO)₂ is prepared by reduction of Cp*₂TiCl₂ in the presence of carbon monoxide.^[3]

Further reading

• U.. Rosenthal. What Do Titano- and Zirconocenes Do with Diynes and Polyynes? . Chemical Reviews. 33 . 2000 . 2. 119–129 . 10.1021/ar9900109. 10673320. etal.

References

1. 10.1021/ja00343a012. Structure and Reactivity of Bis(pentamethylcyclopentadienyl)(ethylene)titanium(II), a Simple Olefin Adduct of Titanium. Journal of the American Chemical Society. 105. 5. 1136–1143. 1983. Cohen. Steven A.. Auburn. Pamela R.. Bercaw. John E..
2. • S. L. . Buchwald . R. B. . Nielsen . Group 4 Metal Complexes of Benzynes, Cycloalkynes, Acyclic Alkynes, and Alkenes . Chemical Reviews. 88 . 7 . 1988 . 1047–1058 . 10.1021/cr00089a004.
3. Book: 10.1002/9780470132593.ch64. Dicarbonylbis(η⁵ -Cyclopentadienyl) Complexes of Titanium, Zirconium, and Hafnium. Inorganic Syntheses. 248–257. 1990. 28. Sikora. David J.. Moriarty. Kevin J.. Rausch. Marvin D.. 9780470132593.