ESR Spectra of the System of the Transition Metal Compound and Trialkyl Aluminum. II. The System of the Vanadium Compound and Trialkyl Aluminum

Abstract

Abstract The ESR spectra of the homogeneous organometallic catalyst system of VOA2-AlEt3 (I) and VCl4-AlEt3 (II) were measured in benzene, toluene, n-hexane and tetrahydrofuran solutions. A superhyperfine structure of nine lines with a g-value of 1.9917, and with a hyperfine splitting of 4.2 gauss on each eight line due to the 51V nucleus, was observed in the systems of I and II in the aromatic solvents at any Al/V ratio from 1 to 15. The same type of spectrum was observed in the VA3-Al(isoBut)3 system in a benzene solution at Al/V ratios higher than 3. In the system of II, the single line was observed at Al/V ratios up to 5. At higher ratios the superhyperfine structure appeared to overlap on the single line. On the basis of these facts, it may be considered that the vanadium atom was reduced to the zerovalent state and was then complexed with aromatic solvents in these systems. This suggests the presence of a sandwich complex such as (Remark: Graphics omitted.) where X=H or CH3.