Porous organic polymers based on cobalt corroles for carbon monoxide binding
Résumé
Porous organic polymers (POPs), known for their high surface area and porosity, were prepared starting
from tetraphenyl tetrahedral-shaped building blocks and corrole macrocyclic linkers either as free bases
or cobalt complexes. This synthetic method allowed us to construct new porous frameworks with high
carbon monoxide adsorption properties. Two synthetic strategies were developed for incorporating
cobalt corroles into the porous matrix. The first method is based on the copper-free Sonogashira crosscoupling
reaction between a free base diodo-corrole with a tetrahedral shaped derivative followed by
cobalt complexation of the resulting material, leading to POP-CorCo-1. The second strategy consists of
preparing POP-CorCo-2 by directly using in the coupling reaction the metalated cobalt corrole temporarily
protected by two ammine ligands at the axial position. The design principles as well as the relationship
between the structure and the selective CO adsorption performance are presented. The adsorption
capacities and selectivities of CO were calculated from a multisite Langmuir isotherm model and using IAST
theory. Spectroscopic studies (NMR, FTIR, UV-visible), kinetic sorption measurements and microscopic analyses
made possible to provide a fairly complete description of the structure of the POPs, their porosity and
the nature of solid–gas interactions. The POPs prepared by both methods show a high permanent porosity
and outstanding CO sorption properties with a high selectivity over N2, O2 and CO2, up to 15700, 4000
and 1800, respectively. The two POP-CorCo therefore offer confined molecular spaces for ascertaining a
high accessibility of the metallocorrole active sites for gas binding on the cobalt atom, thus featuring high
potential for applications in selective capture or sensing of CO versus N2, O2 and CO2.
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