A Programmable KillSwitch in NewTAML Catalysts Decouples Oxidative Reactivity from Catalyst Lifetime.
4 affiliations
- 1Institute of Green Science (IGS), Carnegie Mellon University, Pittsburgh, Pennsylvania15213, United States.
- 2Carnegie Mellon University, Pittsburgh, Pennsylvania15213, United States.
- 3Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Ciudad Universitaria, Ciudad de México04510, Mexico.
- 4Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland21218, United States.
Abstract
Bis-amido-bis-sulfonamido, [Fe{4-NO2C6H3-1,2-(NCOCMe2NSO2)2CR1R2}(OH2)]- [2; R1/R2 = H/H (2a), H/CH3 (2b), CH3/CH3 (2c)], are NewTAML (NT) iron(III) oxidation catalysts. Herein we identify and mechanistically characterize a ligand-centered, catalyst-lifetime-controlling site (CR1R2), termed a KillSwitch (KS), that enables balancing technical performance with potential safety constraints in NT/Oxidant process design. Under catalytic conditions, CR1R2 sites containing two or one hydrogen(s), (2a, 2b, respectively), undergo deprotonation to form electron-rich ylides that accelerate NT oxidative degradation. The 2a-c series defines a KS susceptibility gradient arising from differential C-H bond acidities controlling the ylide-forming deprotonation─2a, 2b, and 2c represent high-susceptibility-, intermediate-susceptibility-, and null-susceptibility KS states, respectively, thereby providing substantial catalyst functional lifetime control with 2a < 2b ≪ 2c. Kinetic analysis gives similar 2a-c rate constants for H2O2 activation (kI) and substrate oxidation (kII), while catalyst inactivation rate constants (ki) increase markedly and differentially with increasing pH for 2a and 2b, but remain pH-independent for 2c, which degrades more slowly through a separate pathway. Access to null-KS 2c─essential for testing the KS hypothesis─required a decade-long synthetic effort culminating in the quantitative methylation of deprotonated 2b. The KS is expected to be transferable to other NTs with oxidative reactivities distinct from 2a-c, enabling a new dimension in catalyst design that broadly decouples catalytic oxidative aggression from catalyst lifetime. The KS thus provides a practical, safe, and sustainable by design strategy for balancing technical performances against catalyst lifetimes, should shorter-lived NTs become desirable in response to discoveries of postrelease NT adverse environmental effects.
Related
- Understanding Programmable Catalysts Versus Dynamic Reactors
- Oxidative C–C Bond Cleavage of 1,2-Diols by Mn-Doped CeO2 Catalysts
- Hydrogen Pretreatment Programs Oxidative Surface Reconstruction for Enhanced Lattice-Oxygen Reactivity in Co3O4
- The reactivity of coordinated and uncoordinated chromate ions in the quasi-intramolecular redox reactions of [pentaamminechromatocobalt(iii)] chloride and chromate resulting in tuneable cobalt-chromium spinel oxide catalysts.
- Template-Derived Nickel Oxide Catalysts for Reproducible Oxidative Dehydrogenation of Ethane
BibTeX
@article{chakraborty2026programmable,
title = {{A Programmable KillSwitch in NewTAML Catalysts Decouples Oxidative Reactivity from Catalyst Lifetime.}},
author = {Debojyoti Chakraborty and Minerva G Schafer and Xiaowei Ma and Chris Birch and Carlos Felipe Mejía and Rubén A Toscano and Ronan Le Lagadec and Maxime A Siegler and Kevin Noonan and Alexander D Ryabov and Terrence J Collins},
journal = {Journal of the American Chemical Society},
year = {2026},
month = oct,
doi = {10.1021/jacs.6c11419},
url = {https://europepmc.org/article/MED/42912295},
note = {CC BY},
}
RIS
TY - JOUR
TI - A Programmable KillSwitch in NewTAML Catalysts Decouples Oxidative Reactivity from Catalyst Lifetime.
AU - Debojyoti Chakraborty
AU - Minerva G Schafer
AU - Xiaowei Ma
AU - Chris Birch
AU - Carlos Felipe Mejía
AU - Rubén A Toscano
AU - Ronan Le Lagadec
AU - Maxime A Siegler
AU - Kevin Noonan
AU - Alexander D Ryabov
AU - Terrence J Collins
PY - 2026
DA - 2026/10/01
JO - Journal of the American Chemical Society
DO - 10.1021/jacs.6c11419
UR - https://europepmc.org/article/MED/42912295
AB - Bis-amido-bis-sulfonamido, [Fe{4-NO2C6H3-1,2-(NCOCMe2NSO2)2CR1R2}(OH2)]- [2; R1/R2 = H/H (2a), H/CH3 (2b), CH3/CH3 (2c)], are NewTAML (NT) iron(III) oxidation catalysts. Herein we identify and mechanistically characterize a ligand-centered, catalyst-lifetime-controlling site (CR1R2), termed a KillSwitch (KS), that enables balancing technical performance with potential safety constraints in NT/Oxidant process design. Under catalytic conditions, CR1R2 sites containing two or one hydrogen(s), (2a, 2b, respectively), undergo deprotonation to form electron-rich ylides that accelerate NT oxidative degradation. The 2a-c series defines a KS susceptibility gradient arising from differential C-H bond acidities controlling the ylide-forming deprotonation─2a, 2b, and 2c represent high-susceptibility-, intermediate-susceptibility-, and null-susceptibility KS states, respectively, thereby providing substantial catalyst functional lifetime control with 2a < 2b ≪ 2c. Kinetic analysis gives similar 2a-c rate constants for H2O2 activation (kI) and substrate oxidation (kII), while catalyst inactivation rate constants (ki) increase markedly and differentially with increasing pH for 2a and 2b, but remain pH-independent for 2c, which degrades more slowly through a separate pathway. Access to null-KS 2c─essential for testing the KS hypothesis─required a decade-long synthetic effort culminating in the quantitative methylation of deprotonated 2b. The KS is expected to be transferable to other NTs with oxidative reactivities distinct from 2a-c, enabling a new dimension in catalyst design that broadly decouples catalytic oxidative aggression from catalyst lifetime. The KS thus provides a practical, safe, and sustainable by design strategy for balancing technical performances against catalyst lifetimes, should shorter-lived NTs become desirable in response to discoveries of postrelease NT adverse environmental effects.
SN - 0002-7863
SN - 1520-5126
ER -