Ring-Opening Reactions of Tetrahydrofuran versus Alkyne Complexation by Group 4 Metallocene Complexes Leading to General Consequences for Synthesis and Reactions of Metallocene Complexes

• Published in: Organometallics Vol. 26; no. 12; pp. 3000 - 3004
• Main Authors: Beweries, Torsten, Jäger-Fiedler, Ulrike, Bach, Marc A, Burlakov, Vladimir V, Arndt, Perdita, Baumann, Wolfgang, Spannenberg, Anke, Rosenthal, Uwe
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 04.06.2007; Amer Chemical Soc
• Subjects: Chemistry; Chemistry, Inorganic & Nuclear; Chemistry, Organic; Physical Sciences; Science & Technology; BIS(TRIMETHYLSILYL)ACETYLENE; ETHYLENE; ZIRCONIUM; CARBON-OXYGEN; CHEMISTRY; CRYSTAL-STRUCTURES; TITANOCENE; BOND-CLEAVAGE; DERIVATIVES; CHLORIDE
• ISSN: 0276-7333; 1520-6041
• DOI: 10.1021/om0702173

The reduction of certain group 4 metallocene dichlorides by magnesium or lithium in the presence or absence of Me3SiC2SiMe3 in THF or toluene was investigated, giving in the case of titanium the dinuclear Ti(III) complex [rac-(ebthi)Ti(μ-Cl)]2 (1). For zirconium the 1-oxa-2-zirconacyclohexane 2 was formed by ring-opening reaction of rac-(ebthi)Zr(η2-Me3SiC2SiMe3) with THF. As a byproduct from the synthesis of Cp*2Zr(η2-Me3SiC2SiMe3) starting from Cp*2ZrCl2 another 1-oxa-2-zirconacyclohexane (3) was obtained by ring-opening reaction of THF via the dinuclear complex Cp*2Zr(Cl)-(CH2)4O−Zr(Cl)Cp*2 (4). In the case of hafnium the analogous dinuclear complex Cp*2Hf(Cl)−(CH2)4O−Hf(Cl)Cp*2 (5) and 1-oxa-2-hafnacyclohexane (6) were the main products of the reaction, inhibiting the synthesis of Cp*2Hf(η2-Me3SiC2SiMe3) (7). The tendency for ring opening of THF initiated by metallocenes increases in the series Ti, Zr, Hf, thus leading to consequences for the synthesis of metallocene complexes.