Isolation of a Self-Activating Ethylene Trimerization Catalyst of a Cr-SNS System

Two pyridine-SNS ligands (2,6-CH2SR)2C5H5N (R = t-Bu (a), n-decyl (b)) were prepared and tested for the possibility of forming active and selective chromium trimerization catalyst precursors. The two trivalent derivatives [(2,6-CH2SR)2C5H5N]CrCl3 (1a,b), and the divalent [(2,6-CH2S(t-Bu)2C5H5N]CrCl2·THF (2a) were isolated and characterized. Upon treatment of 1a with Me3Al, the self-activating, single-component, highly selective chromium trimerization catalyst [2,6-CH2S(t-Bu)2C5H5N]CrMe[(μ-Cl)AlMe3)]2 (3a) was obtained and fully characterized.