Chromophore Quench Labeling: Simulated Snapshots of Molar Mass Distributions for the Rapid Mechanistic Analysis of Catalytic Alkene Polymerization

Herein, a kinetic simulation analysis of catalytic alkene polymerization reactions using the chromophore quench-labeling (CQL) technique is presented. Through this analysis, snapshots of simulated molar mass distributions (MMDs), as observed via gel permeation chromatography (GPC), are provided under several different polymerization scenarios, including living polymerization, β-H elimination, slow initiation, irreversible chain transfer, reversible chain transfer, and select combinations of these scenarios. Importantly, the simulated snapshots of MMDs in this study account for both the refractive index and UV-GPC traces generated under each polymerization scenario, where the UV-GPC traces directly probe the MMDs of catalyst-bound polymeryl species. Thus, this analysis provides unique insights into the kinetic and mechanistic study of polymerization reactions studied via CQL. Also highlighted are the insights gained into reversible chain transfer such as estimates of the minimum rate constants of exchange required to achieve so-called Poisson MMDs and how slow initiation impacts the MMDs obtained during reversible chain transfer. Overall, this manuscript yields a framework for the rapid assessment of polymerization mechanisms. As such, mechanistic analysis of catalytic polymerization reactions using the CQL technique can be conducted in a minimal number of experiments by comparing the experimentally produced MMDs to the simulated MMDs provided herein.