Porphyrin-Based MOF Thin Film on Transparent Conducting Oxide: Investigation of Growth, Porosity and Photoelectrochemical Properties

[EN] Synthesizing metal-organic frameworks (MOFs) composites with a controlled morphology is an important requirement to access materials of desired patterning and composition. Since the last decade, MOF growth from sacrificial metal oxide layer is increasingly developed as it represents an efficient pathway to functionalize a large number of substrates. In this study, porphyrin-based Al-PMOF thin films were grown on conductive transparent oxide substrates from sacrificial layers of ALD-deposited alumina oxide. The control of the solvent composition and the number of atomic layer deposition (ALD) cycles allow us to tune the crystallinity, morphology and thickness of the produced thin films. Photophysical studies evidence that Al-PMOF thin films present light absorption and emission properties governed by the porphyrinic linker, without any quenching upon increasing the film thickness. Al-PMOF thin films obtained through this methodology present a remarkably high optical quality both in terms of transparency and coverage. The porosity of the samples is demonstrated by ellipsometry and used for Zn(II) insertion inside the MOF thin film. The multifunctional transparent, porous and luminescent thin film grown on fluorine-doped tin oxide (FTO) is used as an electrode capable of photoinduced charge separation upon simulated sunlight irradiation.This research was funded by the French National Research Agency grant (ANR-17-CE09- 0029-01 and ANR-10-LABX-0064), and the Region Auvergne Rhone Alpes for the Subvention SCUSI. The authors thank the French Ministry of National Education, Research and Technology, the University Lyon 1 and the CNRS for financial support. S.N. thanks the support of grant PID2021-123856OBI00 funded by MCIN/AEI/10.13039/501100011033 and by ERDF A way of making Europe.Gikonyo, B.; Liu, F.; Hawila, S.; Demessence, A.; Garcia-Baldovi, H.; Navalón Oltra, S.; Marichy, C.... (2023). Porphyrin-Based MOF Thin Film on Transparent Conducting Oxide: Investigation of Growth, Porosity and Photoelectrochemical Properties. Molecules. 28(15). https://doi.org/10.3390/molecules28155876281

Nouvelles chiroporphyrines bridées : synthèse et études de la flexibilité conformationnelle

New chiral porphyrins were designed and synthesized in order to obtain systems where a redox bistability is connected with a conformational switch. The synthesis was inspired by biocartol derived chiral porphyrins already studied in the laboratory: cyclohexyl or cyclopentyl meso-substituted porphyrins with bridles linking two adjacent meso substituents were examined. Thanks to an enzymatic procedure, a kinetic resolution of racemic compound was achieved and led to new chiral porphyrins in both their enantiomeric forms. First, simple systems were studied in order to give an idea of the energies implied in conformational changes. Then, bridled chiroporphyrins with variable bridle length were examined. ln this last case, the influence of bridle length and metallation of the porphyrin on the conformational equilibriums were studied by spectroscopic techniques: nuclear magnetic resonance and circular dichroism.De nouvelles porphyrines chirales ont été conçues et synthétisées dans le but d'accéder à des systèmes où une bistabilité redox pourrait être reliée à une bistabilité conformationnelle. La synthèse de porphyrines portant en méso des substituants cyclohexyl ou cyclopentyl liés deux à deux de façon chirale a été étudiée, en s'inspirant de la structure des porphyrines dérivées du biocartol, étudiées précédemment au laboratoire. La synthèse des nouvelles molécules chirales a pu être menée à bien grâce à la mise en œuvre d'une résolution cinétique du racémique par voie enzymatique. Ainsi, ces porphyrines chirales ont pu être synthétisées dans leurs deux formes énantiomériques. Dans un premier temps des systèmes de porphyrines simples ont été étudiés dans le but de connaitre les énergies de changements conformationnels de ces porphyrines. Dans un second temps nous avons caractérisé les chiroporphyrines bridées, de longueur de bride variable (de 5 à 10 groupements méthylènes). Pour ce cas, l'influence de la longueur de bride et de la métallation sur les équilibres conformationnels a été étudiée par des techniques spectroscopiques: résonance magnétique nucléaire et dichroïsme circulaire.GRENOBLE1-BU Sciences (384212103) / SudocSudocFranceF

Porphyrin and phthalocyanine-based metal organic frameworks beyond metal-carboxylates

International audienceGiven the ubiquitous role of porphyrins in natural systems, these molecules and related derivatives such as phthalocyanines are fascinating building units to achieve functional porous materials. Porphyrin-based MOFs have been developed since the past three decades, yet chemically robust frameworks, necessary for applications, have been achieved much more recently and this field is expanding. This progress is partially driven by the development of porphyrins and phthalocyanines bearing alternative coordinating groups (phosphonate, azolates, phenolates…) that allowed to move the related MOFs beyond metalcarboxylates and achieve new topologies and properties. In this perspective article we first give a brief outline of the synthetic pathways towards simple porphyrins and phthalocyanines bearing these complexing groups. The related MOF compounds are then described; their structural and textural properties are discussed, as well as their stability and physical properties. An overview of the resulting nets and topologies is proposed, showing both the similarities with metal-carboxylate phases and the peculiarities related to the alternative coordinating groups. Eventually, the opportunities offered by this recent research topic, both in term of synthesis pathways, modulation of pore size and shape, stability and physical properties, are discusse

Insightful contribution of 57Fe Mössbauer spectrometry (and of Jean-Marc Grenèche) to the field of iron metal organic frameworks

International audienceWe describe here the relevant input of Mossbauer spectrometry for the investigation of porous coordination polymers, or metal organic frameworks (MOFs) containing iron cations. We specifically focus on selected examples taken from the long-lasting collaboration between the physicist Jean-Marc Greneche and French MOF chemists issued from the group of late Gerard Ferey. After a brief historical recall, we discuss the expected inputs of Mossbauer spectrometry for chemists working on the synthesis and characterization of new MOFs materials. Two examples are thoroughly described: a series of flexible MOFs presenting the MIL-53 topology, and MOFs based on porphyrin ligands. Through these examples, we will show how the combination of characterization tools (notably X-ray diffraction and Mossbauer spectrometry) is mandatory to achieve a thorough and accurate description of these complex porous hybrid materials and their properties

Post-synthetic functionalization and ligand exchange reactions in gold(i) phenylthiolate-based coordination polymers

SSCI-VIDE+CDFA+ADMInternational audienceGold thiolate coordination polymers (CPs) are anisotropic materials with 1D or 2D networks exhibiting a large palette of photoluminescence properties. In this paper, we show that, from both lamellar acid and ester, [Au(p-SPhCO2X)]n CPs (X = H, Me), it is possible to perform post-synthesis esterification or saponification reactions. Three new 2D phases with X = Na, K and Cs were isolated. In addition, ligand exchange reactions were carried out from 1D [Au(p-SPh)]n CP and 2D [Au(p-SPhCO2X)]n CPs (X = H, Me) and the transformations from 1D to 2D structures and vice versa point out a mechanism of dissolution and recrystallization that is governed by the nature of the ligands and the presence of weak interactions. The obtained compounds exhibit solid state and RT photoemission characteristic of their structure

Confinement of Fe–Al-PMOF catalytic sites favours the formation of pyrazoline from ethyl diazoacetate with an unusual sharp increase of selectivity upon recycling

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Synthesis and Conformational studies of chiral meso-(a,b-unsaturated)-porphyrins

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Flexible and luminescent fibers of a 1D Au( i )–thiophenolate coordination polymer and formation of gold nanoparticle-based composite materials for SERS

International audienceShaping of functional materials is of tremendous importance for applications. Among coordination polymer compounds, one of the challenges is to get fibers that can be self-standing and flexible, while maintaining their crystallinity and properties. Here, the synthesis and characterization of free-standing fibers of a Au(I)-based coordination polymer (CP) are reported. The flexible fibers of the 1D gold(I)–thiophenolate [Au(SPh)]n CP have an average diameter of 270 nm and length of a few micrometers. They are hydrophobic because of the presence of phenyl rings and exhibit high chemical stability in harshly acidic and basic conditions due to the strong Au(I)–S interactions. These fibers are red-emissive at room temperature because of the presence of aurophilic interactions. In addition, a composite material can be easily obtained through calcination, resulting in the formation of gold nanoparticles (AuNPs) on the CP fiber surface. Owing to the plasmonic resonance of AuNPs, this composite material exhibits good sensitivity towards the detection of molecules as observed through surface enhanced Raman scattering (SERS)

A New Lamellar Gold Thiolate Coordination Polymer, [Au(m-SPhCO2H)]n, for the Formation of Luminescent Polymer Composites

SSCI-VIDE+CDFA+OVE:ADMInternational audienceThe photoluminescence of gold thiolate clusters brings about many potential applications, but its origin is still elusive because of its complexity. A strategy in understanding the structure-properties relationship is to study closely related neutral gold thiolate coordination polymers (CPs). Here, a new CP is reported, [Au(m-SPhCO 2 H)] n. Its structure is lamellar with an inorganic layer made of Au-S-Au-S helical chains, similar to the [Au(p-SPhCO 2 H)] n analog. An in-depth study of its photophysical properties revealed that it is a bright yellow phosphorescent emitter with a band centered at 615 nm and a quantum yield (QY) of 19% at room temperature and in a solid state. More importantly, a comparison to the para-analog, which has a weak emission, displayed a strong effect of the position of the electron withdrawing group (EWG) on the luminescent properties. In addition, [Au(m-SPhCO 2 H)] n CPs were mixed with organic polymers to generate transparent and flexible luminescent thin films. The ability to tune the emission position with the appropriate contents makes these nontoxic polymer composites promising materials for lighting devices

Supramolecular assemblies of phenolic metalloporphyrins: Structures and electrochemical studies

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