{"doi":"10.1021/acs.macromol.0c00552","title":"Quantitative Validation of the Living Coordinative Chain-Transfer Polymerization of 1-Hexene Using Chromophore Quench Labeling","abstract":"In this report, we apply the chromophore quench-labeling (CQL) technique to living, homogeneous polymerization catalysts and living coordinative chain-transfer polymerization (LCCTP) conditions. We observe 100% active site counts via CQL for 1-hexene polymerization as catalyzed by two different cyclopentadienyl amidinate (CPAM) group 4 metal complexes, both previously reported to be living polymerization catalysts. We obtain a rate constant for the propagation of 1-hexene catalyzed by the CPAM hafnium complex. Selective iodinolysis and 1H NMR analysis of polymer chain ends enable the quantification of Zn–polymeryls; at low conversions (∼10% conversion), nearly 2 polymer chains per Zn are observed. Through Mayo analysis and kinetic simulations, we estimate the rate of Hf–polymeryl for Zn–ethyl exchange in polymerization. Beyond active site counting, the chromophore quench-labeling method enables the observation of catalyst-bound polymeryl molecular mass distributions (MMDs) using gel permeation chromatography (GPC) with an inline UV detector (UV-GPC). Comparison of the MMDs of catalyst-bound polymeryls and all polymer chains (measured using refractive index detection, RI-GPC) reveals important mechanistic details. With the exception of early time points in the reaction, we observe excellent overlap between the UV-GPC and the RI-GPC traces. These results reveal that equilibration of polymer chains on Hf and Zn occurs rapidly in the LCCTP of 1-hexene using the CPAM hafnium complex as the catalyst and diethyl zinc as the chain-transfer agent. Kinetic simulations indicate that the Hf–polymeryl for Zn–polymeryl exchange leads to the good overlap between UV-GPC and RI-GPC traces and a crude estimate for the rate constant of this process.","journal":"Macromolecules","year":2020,"id":98596,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":31,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9575,"is_data_producer":false,"deposit_databanks":null,"is_oa":false,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2020-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":486373,"name":"Lawrence R. Sita","orcid":"0000-0002-9880-1126","position":1,"is_corresponding":false},{"id":486374,"name":"Clark R. Landis","orcid":"0000-0002-1499-4697","position":2,"is_corresponding":false},{"id":486372,"name":"Eric S. Cueny","orcid":"0000-0003-1244-2407","position":0,"is_corresponding":true}],"reference_count":66,"raw_metadata":null,"created_at":"2026-07-18T22:36:58.511143Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}