Coordination compound that by reaction with an activator or cocatalyst provides an active catalyst during
initialization of
coordination polymerization.
Examples: Catalyst precursors are certain transition metal or rare-earth metal complexes, such as titanium tetrachloride or bis(cyclopentadienyl)titanium chloride.
Source:
PAC, 2022, 94, 1093. 'Terminology for chain polymerization (IUPAC Recommendations 2021)' on page 1116 (https://doi.org/10.1515/pac-2020-1211)