Synthesis, Characterization, and Heterobimetallic Cooperation in a Titanium–Chromium Catalyst for Highly Branched Polyethylenes

A heterobimetallic
catalyst, {Ti--Cr}, consisting
of a constrained-geometry titanium olefin polymerization center (CGCEtTi) covalently linked to a chromium bis­(thioether)­amine
ethylene trimerization center (SNSCr) was synthesized
and fully characterized. In ethylene homopolymerizations it affords
linear low-density polyethylene with molecular weights as high as
460 kg·mol–1 and exclusively n-butyl branches in conversion-insensitive densities of ∼18
branches/1000 carbon atoms, which are ∼17 and ∼3 times
(conversion-dependent), respectively, those achieved by tandem mononuclear CGCEtTi and SNSCr catalysts under
identical reaction conditions.