mediating agent

synonym: mediator
https://doi.org/10.1351/goldbook.08964
Species that mediates polymerization in reversible-deactivation polymerization.

Examples: The aminoxyl radical in aminoxyl-mediated radical polymerization (AMRP) and the RAFT agent in RAFT polymerization.

Source:
PAC, 2022, 94, 1093. (Terminology for chain polymerization (IUPAC Recommendations 2021)) on page 1124 [Terms] [Paper]