Polymerization on activated ligands

In studies of cyclic monomer opening on transition metal derivatives, particularly on TiCl4, we have observed a peculiar kind of propagation. It occurs at activated ligands (chloromethyloxirane, acetylchloride) coordinated to Ti by chloride atoms. 

We assume that contact of the ligands with the monomer (methyloxirane, tetrahydrofuran) leads to bond redistribution and monomer insertion between the atoms of the growing ligand [347] 

The proposed mechanism plausibly explains the observed facts. An independent, direct proof of its validity is not yet available. 

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