Selective trapping of carbon monoxide with cobalt corroles to aim the development of a gas sensor

Ces travaux de thèse ont pour objectif la synthèse de nouveaux corroles de cobalt pour la détection à des concentrations sub-ppm de CO. La détection du monoxyde de carbone à de telles concentrations représente des enjeux de santé publique et industriel.Lors de ces travaux de thèse, les corroles de cobalt tétra-coordinés synthétisés se sont révélés instables dans le temps. Une nouvelle stratégie a été utilisée en se servant de ligands axiaux labiles comme groupements protecteurs des corroles de cobalt. Cette stratégie a permis d’élaborer un capteur détectant le monoxyde de carbone à des seuils de l’ordre du ppb.Enfin la dernière partie de ce travail concerne le développement de nouveaux matériaux poreux à base de corroles de cobalt dont les résultats se révèlent prometteurs pour la détection et le stockage du monoxyde de carbone.This work aims to develop cobalt corroles for sub-ppm carbon monoxide detection. Surnamed “the silent killer”, detection at low-level of this gas represents a public health and an industrial challenge.During this work, synthesized tetra-coordinated cobalt corroles were found to be not stable over time. A new approach was developed, using labile axial ligands as protective groups of the tetra-coordinated cobalt corrole. This strategy leads to a ppb level detection sensor.The synthesis of new porous organic polymer based on cobalt corroles represents the last part of this work. Gas sorption measurement of these new materials are encouraging for their development for carbon monoxide detection or storage

Reinvestigation of the synthesis of “covalent-assembly” type probes for fluoride ion detection. Identification of novel 7-(diethylamino)coumarins with aggregation-induced emission properties

International audienceAn unprecedented C-3 functionalization of 4-(diethylamino)salicylaldehyde through a Friedel-Crafts type alkylation reaction has been discovered during the synthesis of “covalent-assembly”-based fluorescent probes for detection of fluoride ions. The resulting Friedel-Crafts adduct was successfully used for the preparation of two novel 8-substituted 7-(diethylamino)coumarin dyes. The photophysical study of these fluorophores has enabled us to highlight their remarkable aggregation-induced emission (AIE) properties characterized by a yellow-orange emission of aggregates in water. Therefore, 4-(tert-butyldimethylsilyloxy)benzyl substituent was identified as a novel AIE-active moiety which could be seen as a possible alternative to popular tetraphenylethylene (TPE)

Reinvestigation of the Synthesis of "Covalent-Assembly" Type Probes for Fluoride Ion Detection. Identification of Novel 7-(Diethylamino)coumarins with Aggregation-Induced Emission Properties

An unprecedented C-3 functionalization of 4-(diethylamino)salicylaldehyde through a Friedel-Crafts type alkylation reaction has been discovered during the synthesis of "covalent-assembly"-based fluorescent probes for detection of fluoride ions. The resulting Friedel-Crafts adduct was successfully used for the preparation of two novel 8-substituted 7-(diethylamino)coumarin dyes. The photophysical study of these fluorophores has enabled us to highlight their remarkable aggregation-induced emission (AIE) properties characterized by a yellow-orange emission of aggregates in water. Therefore, 4-(tert butyldimethylsilyloxy)benzyl substituent was identified as a novel AIE-active moiety which could be seen as a possible alternative to popular tetraphenylethylene (TPE)

N-Alkylation of 2-Methoxy-10H-Phenothiazine Revisited. A Facile Entry to Diversely N-substituted Phenothiazine-Coumarin Hybrid Dyes

N-Alkylation of 2-methoxy-10H-phenothiazine, a valuable building block for the synthesis of bioactive compounds and reaction-based fluorescent probes, has been revisited aimed at introducing a substituent easily convertible into cationic or zwitterionic side chains. We focused our attention on the 3-dimethylaminopropyl group since its derivatization through reactions with various alkyl halides or sultones is a well-established and effective way to enhance polarity of diverse hydrophobic molecular scaffolds. This two-step functionalization approach was applied to the synthesis of novel phenothiazine-coumarin hybrid dyes whose spectral features, especially their NIR-I emission, have been determined in aqueous media with the ultimate goal of identifying novel fluorescent markers for bioanalytical applications, including fluorogenic detection of reactive oxygen species (ROS) through selective S-oxidation reaction of phenothiazine scaffold. </div

Porous organic polymers based on cobalt corroles for carbon monoxide binding

International audiencePorous 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 incorporatingcobalt 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 temporarilyprotected 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 CO

Cobalt corroles for selective detection of carbon monoxide

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Porous Organic Polymers (POPs) based on cobalt corroles for the detection of carbon monoxide

International audienceDetection of carbon monoxide (CO) at few ppm levels is a critical point for quality control of domestic and<br&gtindustrial environment. CO is responsible for thousands of intoxications and hundreds of deaths per year in the<br&gtworld. Moreover, CO is a residual gas found in the industrial dihydrogen used for Proton Exchange Membrane<br&gtfuel cell, and deactivates the fuel cell prematurely. Corroles have been largely used in sensing applications.[1]<br&gtCobalt corroles display high binding affinity for carbon monoxide even in the presence of nitrogen and<br&gtdioxygen.[2] The affinity of the Co(III) metallocorroles for CO is directly correlated with the Lewis acid character<br&gtof the metal center. Therefore, structural modifications on the aromatic ring have a direct influence on the<br&gtreactivity of the metal complex. We have recently obtained very low CO detection level (ppm) using SAW<br&gtdevices functionalized by cobalt corrole deposited as a film on an alumina or a gold surface.[3] Our previous work<br&gton the synthesis of porous sol-gel materials functionalized by cobalt corroles gave us encouraging results for CO<br&gtsorption and detection[4] and prompted us to prepare new porous structured materials functionalized by corrole<br&gtcomplexes for gas detection applications. Among all the methods of synthesis of porous architectures, organic<br&gtmaterials belonging to the POP (Porous Organic Polymer) family are an appealing and original approach in this<br&gtresearch field.[5] Herein, we describe the synthesis of new POPs functionalized by cobalt corroles (Fig. 1). Their<br&gtselective sorption properties for CO over N2, O2 and CO2 will be also presented

Design, synthesis and evaluation of enzyme-responsive fluorogenic probes based on pyridine-flanked diketopyrrolopyrrole dyes

International audienceThe ever-growing demand for fluorogenic dyes usable in the rapid construction of analyteresponsive fluorescent probes, has recently contributed to a revival of interest in the chemistry of diketopyrrolopyrrole (DPP) pigments. In this context, we have explored the potential of symmetrical and unsymmetrical DPP derivatives bearing two or one 4-pyridyl substituents acting as optically tunable group(s). The unique fluorogenic behavior of these molecules, closely linked to N-substitution/charge state of their pyridine unit (i.e., neutral pyridine or cationic pyridinium), has been used to design DPP-based fluorescent probes for detection of hypoxia-related redox enzymes and penicillin G acylase (PGA). In this paper, we describe synthesis, spectral characterization and bioanalytical validations of these probes. Dramatic differences in terms of aqueous stability and enzymatic fluorescence activation were observed. This systematic study enables to delineate the scope of application of pyridine-flanked DPP fluorophores in the field of enzyme biosensing