Ligand radicals tune LPMO activity in model complex.
NETTO, Caterina Gruenwaldt Cunha Marques; PANDEY, Ritika; CASTRO, Caio Bezerra de; MORENO, Larissa; FERREIRA, Millena Pereira; RODRIGUES, Lullie Gomes; GUIMARÃES JÚNIOR, Walber Gonçalves; DE ARAUJO NETO, João Honorato; CONCIANI, Gabrielle Rodrigues; DYER, Richard Brian; JANNUZZI, Sergio Augusto Venturinelli; MOURA, André Farias de; SOUZA, Dulce Helena Ferreira de; NASCIMENTO, Otaciro Rangel.
NETTO, Caterina Gruenwaldt Cunha Marques; PANDEY, Ritika; CASTRO, Caio Bezerra de; MORENO, Larissa; FERREIRA, Millena Pereira; RODRIGUES, Lullie Gomes; GUIMARÃES JÚNIOR, Walber Gonçalves; DE ARAUJO NETO, João Honorato; CONCIANI, Gabrielle Rodrigues; DYER, Richard Brian; JANNUZZI, Sergio Augusto Venturinelli; MOURA, André Farias de; SOUZA, Dulce Helena Ferreira de; NASCIMENTO, Otaciro Rangel.
Abstract: Radicals are essential to the catalytic chemistry of metalloenzymes, enabling reactivity and self-protection through controlled redox processes. In copper-dependent LPMOs, amino acid radicals mediate oxidative transformations via hole hopping. However, the generation and role of ligand-centered radicals in synthetic copper models remain poorly understood. Here we show that an l-proline-based N,N,O,O-coordinated copper complex (4) generates stable carbon-centered ligand-radicals. A markedly higher population of these ligand radicals was observed in this complex than in the N,N,N-coordinated analogues (complexes 1-3). Catalytically, complex 4 outperforms complexes 1-3, effectively degrading 4-nitrophenyl-ß-d-glucopyranoside, cellobiose, and cellulose using either H2O2 or O2. The superior performance of complex 4 is linked to its lower steric hindrance, a key factor in LPMO mimicry. These results establish ligand-centered radicals as key functional analogues of enzymatic redox pathways and offer a blueprint for designing self-protecting copper oxidation catalysts.
@article={003294335,author = {NETTO, Caterina Gruenwaldt Cunha Marques; PANDEY, Ritika; CASTRO, Caio Bezerra de; MORENO, Larissa; FERREIRA, Millena Pereira; RODRIGUES, Lullie Gomes; GUIMARÃES JÚNIOR, Walber Gonçalves; DE ARAUJO NETO, João Honorato; CONCIANI, Gabrielle Rodrigues; DYER, Richard Brian; JANNUZZI, Sergio Augusto Venturinelli; MOURA, André Farias de; SOUZA, Dulce Helena Ferreira de; NASCIMENTO, Otaciro Rangel.},title={Ligand radicals tune LPMO activity in model complex},journal={Inorganic Chemistry},note={v. 65, n. 10, p. 5357-5373 + supporting information},year={2026}}