Cobalt Corroles: From Monomolecular Binding to Porous Organic Polymers (POPs) for the Selective Detection of Carbon Monoxide (CO)

Detection of carbon monoxide (CO) at few ppm levels is a critical point for quality control of domestic and industrial environment. CO is responsible for thousands of intoxications and hundreds of deaths per year in the world. Moreover, CO is a residual gas found in the industrial dihydrogen used for Proton Exchange Membrane fuel cell, and deactivates the fuel cell prematurely. Corroles have beenlargely used in sensing applications.[1] Cobalt corroles display high binding affinity for carbon monoxide even in the presence of nitrogen and dioxygen.[2] The affinity of the Co(III) metallocorroles for CO is directly correlated with the Lewis acid character of the metal center. Therefore, structural modifications on the aromatic ring have a direct influence on the reactivity of the metal complex. We have recently obtained very low CO detection level (ppm) using SAW devices functionalized by cobalt corrole deposited as a film on a guiding layer of silica or a gold surface.[3] Tetra-coordinated cobalt corroles were found to be not so stable over time. A new approach was developed, using labile axial ligands as a protective group of the tetra-coordinated metal complexes. We will present the e-chem and spectro e-chem properties of the cobalt complexes with different axial ligands. As our previous work on the synthesis of porous sol-gel materials functionalized by cobalt corroles gave us also encouraging results for CO sorption and detection[4], we have prepared new porous structured materials functionalized by corrole complexes for gas detection applications. Among all the methods of synthesis of porous architectures, organic materials belonging to the POP (Porous Organic Polymer) family are an appealing and original approach in this research field.[5] We will thus describe the synthesis of new POPs functionalized by cobalt corroles (Fig. 1). Their selective sorption properties for CO over N₂, O₂and CO₂will be also presented.

Authors would like to acknowledge the ANR program (CO³SENS project), the FEDER and the "Région Bourgogne" for financial support, and for the allocation of a PhD grant (JCE Program).

REFERENCES:[1] Paolesse, R.; Nardis,S.; Monti, D.; Stefanelli, M.; Di Natale, C., Chem. Rev.2017, 117, 2517–2583;[2] J.-M. Barbe, G. Canard, S. Brandès, F. Jerôme, G. Dubois, R. Guilard, Dalton Trans. 2004, 1208-1214; [3] M. Vanotti, C. Theron, S. Poisson, V. Quesneau, M. Naitana, V. Soumann, S. Brandès, N. Desbois, C. Gros, T.-H. Tran-Thi, V. Blondeau-Patissier, Proceedings 2017, 1, 444-447; [4] J. M. Barbe, G. Canard, S. Brandès, R. Guilard, Chem. Eur. J. 2007, 13, 2118-2129; [5] S. Brandès, V. Quesneau, O. Fonquernie, N. Desbois, V. Blondeau-Patissier, C. P. Gros, Dalton Trans. 2019, 48, 11651-11662 (Cover).

Figure 1