Preparation, characterization and activity of CuZn and Cu2 superoxide dismutase mimics encapsulated in mesoporous silica

Matías Patriarca (1) , Veronica Daier (1) , Gerardo Camí (1) , Eric Rivière (2) , Christelle Hureau (3) , Sandra Signorella (1)

1 IQUIR - Instituto de Química Rosario
2 ICMMO - Institut de Chimie Moléculaire et des Matériaux d'Orsay
3 LCC - Laboratoire de chimie de coordination

Encapsulation of three superoxide dismutase (SOD) functional mimics, [CuZn(dien)2(μ-Im)(ClO4)2]ClO4 (1), [Cu2(dien)2(μ-Im)(ClO4)2]ClO4 (2) (Im = imidazolate, dien = diethylenetriamine), and [CuZn(salpn)Cl2] (3) (H2salpn = 1,3-bis(salicylideneamino)propane) in mesoporous MCM-41 silica afforded three hybrid catalysts 1@MCM-41, 2@MCM-41 and 3@MCM-41. Spectroscopic and magnetic analyses of these materials confirmed the metal centers of the complexes keep the coordination sphere after insertion into the MCM-41 silica matrix. For the imidazolate-bridged complexes the silica channels restraint the relative orientation of the two metal ions. While 3@MCM-41 shows SOD activity significantly lower than the host-free complex, insertion of the imidazolate-bridged CuZn or Cu2 complexes by ion exchange onto mesoporous MCM-41 silica affords durable and recoverable supported catalysts with much better SOD activity than the free complexes. For confined imidazolate-bridged complexes, 1@MCM-41 and 2@MCM-41, the small pore size of the silica matrix improves the SOD activity more than a host with larger pores. This high SOD activity is attributed to the close-fitting of the complexes into the nanochannels of MCM-41 silica that favors the Cu active site and HImZn(or Cu) group stay in close proximity during catalysis.

Mots clés: Biomimics; encapsulated CuZn complexes; mesoporous MCM-41 silica; SOD activity

Domaines: Chimie de coordination

Matías Patriarca, Veronica Daier, Gerardo Camí, Eric Rivière, Christelle Hureau, et al.. Preparation, characterization and activity of CuZn and Cu2 superoxide dismutase mimics encapsulated in mesoporous silica. Journal of Inorganic Biochemistry, 2020, 207, pp.111050. ⟨10.1016/j.jinorgbio.2020.111050⟩. ⟨hal-02611146⟩