The reaction of Cp ∗ CpTiCl 2 ∗ (Cp ∗ : C 5 (CH 3 ) 5 ; Cp: C 5 H 5 ) with two equivalents of vinyllithium enables the first isolation of a titanium(IV)-divinyl complex Cp ∗ CpTi(CHCH 2 ) 2 11. In a molar ratio of 1:1 Cp ∗ CpTi(CH=CH 2 )Cl (15) can be obtained and converted into Cp ∗ CpTi(CHCH 2 )CH 3 16 through further alkylation. In solution at a temperature above 0°C a quantitative isomerisation of 11 to the methylidenemetallacyclobutane occurs as a consequence of characteristic α-H-transfer. The influence on the stability of 11 and 16 through Cp∗/Cp exchance will be discussed in comparison to Cp 2 ∗ Ti derivatives on the basis of NMR data.
The reaction of Cp ∗ CpTiCl 2 ∗ (Cp ∗ : C 5 (CH 3 ) 5 ; Cp: C 5 H 5 ) with two equivalents of vinyllithium enables the first isolation of a titanium(IV)-divinyl complex Cp ∗ CpTi(CHCH 2 ) 2 11. In a molar ratio of 1:1 Cp ∗ CpTi(CH=CH 2 )Cl (15) can be obtained and converted into Cp ∗ CpTi(CHCH 2 )CH 3 16 through further alkylation. In solution at a temperature above 0°C a quantitative isomerisation of 11 to the methylidenemetallacyclobutane occurs as a consequence of characteristic α-H-transfer. The influence on the stability of 11 and 16 through Cp∗/Cp exchance will be discussed in comparison to Cp 2 ∗ Ti derivatives on the basis of NMR data.