Collect. Czech. Chem. Commun. 2011, 76, 177-191
Published online 2011-02-15 10:37:41

Dehydrocoupling of SiMe2H substituents in permethylated zirconocene complexes

Jiří Pinkasa, Róbert Gyepesb,c, Ivana Císařováb, Jiří Kubištaa, Karel Macha and Michal Horáčeka,*

a J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, v.v.i., Dolejškova 3, 182 23 Prague 8, Czech Republic
b Department of Inorganic Chemistry, Charles University, Hlavova 2030, 128 40 Prague 2, Czech Republic
c Present address: J. Selye University, Pedagogical Faculty, Bratislavská cesta 3322, 945 01 Komárno, Slovak Republic,


Complex [Zr{η5-C5Me4(SiMe2H)}2Cl2] (1) was prepared by the reaction of lithium salt of 2,3,4,5-tetramethyl-1-(dimethylsilyl)cyclopenta-2,4-diene with [ZrCl4] in boiling THF. The reduction of 1 with excess magnesium in THF in the presence of excess bis(trimethylsilyl)acetylene (btmsa) afforded the bivalent metal ansa-disilylene complex with π-coordinated btmsa [Zr(η2-btmsa){η5-C5Me4(SiMe2)}2] (2). The dehydrocoupling of SiMe2H groups was accompanied by a hydrogen transfer to releasing btmsa to give a mixture of cis- and trans-1,2-bis(trimethylsilyl)ethene. Chlorination of 2 with PbCl2 afforded ansa-[Zr{η5-C5Me4(SiMe2)}2Cl2] (3) and liberated btmsa. The crystal structures of complexes, 1, 2 and 3 have been determined by X-ray crystallography.

Keywords: Metallocenes; Zirconium; Bridging ligands; Zirconocene; Dimethylhydrosilyl substituent; Dehydrocoupling; Bis(trimethylsilyl)acetylene complex; ansa-Zirconocene; Bis(dimethylsilylene) bridge; Crystal structure.

References: 62 live references.