Gently warming the η6,η5-bis(indenyl) zirconium dimethoxyethane compound (η6-C9H 5-1,3-(SiMe3)2)-(η5-C 9H5-1,3-(SiMe3)2)Zr(DME) (1-DME) to 45°C resulted in C-O bond scission to yield an equimolar mixture of the zirconocene ethylene compound (η5-C9H 5-1,3-(SiMe3)2)2Zr(η 2-CH2=CH2) and the corresponding zirconium bis(methoxide) complex (η5-C9H5-1,3- (SiMe3)2)2Zr(OMe)2. Monitoring the relative rates of 1-DME versus 1-DME-d10 cleavage by 1H NMR spectroscopy established no kinetic isotope effect (kH/k D = 1.0(1)), eliminating the possibility of C-H activation in or prior to the rate-determining step. Computational studies support a pathway involving rate-determining DME dissociation from the η6, η5-bis(indenyl)zirconium complex followed by facile η6 to η5 indenyl haptotropic rearrangement and C-O bond scission. Corresponding C-S bond cleavage chemistry has been investigated for three thioethers and the mechanism of bond activation compared to the oxygen congeners.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry