From metallic cluster-based ceramics to nematic hybrid liquid crystals: a double supramolecular approach.

International audienceWe describe a new supramolecular approach combining host-guest and electrostatic interactions to design hybrid materials containing polyanionic bulky inorganic compounds and showing liquid crystalline properties

Liquid crystal properties resulting from synergetic effects between non-mesogenic organic molecules and a one nanometre sized octahedral transition metal cluster.

International audienceThis work presents the synthesis and studies of a red-NIR luminescent liquid crystal compound based on an octahedral metallic cluster core orthogonally bounded to six non-mesogenic organic ligands. It evidences synergetic effects between the organic and inorganic parts of the hybrid, resulting in the generation of liquid crystal properties on cooling from the isotropic melt

Deep red luminescent hybrid copolymer materials with high transition metal cluster content

Accepted 04 Dec 2013International audienceThe hybrid strategy is a powerful approach to design functional materials by combining inorganic dyes with an organic matrix. However, introducing high contents of inorganic species within the hybrid material is a real challenge that requires a perfect balance between the interactions of both components to avoid mainly phase segregation problems. Based on our demonstration on an anionic molybdenum cluster, we present a general method to introduce high contents of such class of nanometre sized inorganic molecular deep red dyes in a polymer matrix. Our strategy exploits the physical interactions between the organic and inorganic parts of the hybrid material and allows a high cluster rate to be introduced (up to 50 wt%) in the polymer matrix. The resulting hybrids are remarkably stable even after several months of ageing. Moreover, the Mo clusters maintain their intrinsic deep red luminescence properties while the polymer organic matrix fully maintains its processability, thanks to the di-anionic character of the Mo6 clusters. Such materials show promising prospects in applications needing deep red emitters

Nanocomposite polymère-clusters inorganiques pour la photonique intégrée : guides rubans et nanostructures-1D

National audienc

Supramolecular Anchoring of Octahedral Molybdenum Clusters onto Graphene and Their Synergies in Photocatalytic Water Reduction

"This document is the Accepted Manuscript version of a Published Work that appeared in final form in Inorganic Chemistry, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/10.1021/acs.inorgchem.9b02529"[EN] Dihydrogen (H-2) production from sunlight should become one of the most important energy production means in the future. To reach this goal, low-cost and efficient photocatalysts still need to be discovered. Here we show that red near-IR luminescent metal cluster anions, once combined with pyrene-containing cations, are able to photocatalytically produce molecular hydrogen from water. The pyrene moieties act simultaneously as energy transmitters and as supramolecular linkers between the cluster anions and graphene. This association results in a hybrid material combining the emission abilities of pyrene and cluster moieties with the electronic conduction efficiency of graphene. Hydrogen evolution reaction (HER) studies show that this association induces a significant increase of H 2 production compared to that produced separately by clusters or graphene. Considering the versatility of the strategy described to design this photocatalytic hybrid material, transition-metal clusters are promising candidates to develop new, environmentally friendly, and low-cost photocatalysts for HER.The Severo Ochoa Program (SEV-2016-0683), Ministerio de Ciencia, Innovation y Universidades (PGC2018-099744), Consejo Superior de Investigaciones Cientificas (I-Link1063), and University of Rennes are thanked for financial support. We thank Dr. Marta Puche for her technical assistance with the preparation of dispersed graphene solutions at the ITQ.Feliz Rodriguez, M.; Atienzar Corvillo, PE.; Amela-Cortes, M.; Dumait, N.; Lemoine, P.; Molard, Y.; Cordier, S. (2019). Supramolecular Anchoring of Octahedral Molybdenum Clusters onto Graphene and Their Synergies in Photocatalytic Water Reduction. Inorganic Chemistry. 58(22):15443-15454. https://doi.org/10.1021/acs.inorgchem.9b02529S1544315454582

Electroswitchable red-NIR luminescence of ionic clustomesogen containing nematic liquid crystalline devices.

International audienceWe describe in this work several polyionic hybrid mol. compds. combining, by electrostatic interactions, liq. cryst. ammonium cations and tailor made molybdenum hexanuclear dianionic cluster units. All hybrids show nematic liq. cryst. behavior below 100 °C, no matter the nature of the metallic cluster apical and inner ligands. They also retain the shiny deep red photoluminescence properties of their parent cluster in the nematic phase. This nematic phase remains however quite viscous for all compds. and mixing them with com. available nematic LCs seems mandatory to integrate them into electroswitchable devices. This particularity conducted us to insert the best candidate in terms of homogeneity and stability of the clustomesogen/com. LC mixt. into a LC cell and study the behavior toward the application of an elec. stimulus. We show that the application of 30 V AC voltage allows observing a reversible modulation of the photoluminescence signal by about 52%. This work presents the first deep red photoluminescent transition metal cluster contg. device directed towards optoelectronic applications

SYNTHESIS AND CHARACTERIZATION OF NANOCOMPOSITES COATING BASED ON INORGANIC OCTAHEDRAL CLUSTER UNITS FABRICATED BY ELECTROPHORETIC DEPOSITION PROCESS

Composite nanoarchitectures represent a new class of nanostructured entities that integrate various dissimilar nanoscale building blocks including clusters, particles, wires and films [1]. The heterogeneous composite nanostructured materials are composed by definition of multi-(nano)components, each tailored to address different requirements. As one of the nanocomponents, nanometer sized transition metal clusters (\u3c2 nm), which consist of less than a few dozens of metal atoms, could be defined as a link between atom and nanoparticle [2-7]. In this presentation, the first preparation of functional thin films based on octahedral molybdenum metal clusters deposited on ITO glass substrate by EPD will be discussed in detail [8]. More generally, we will focus on our recent results on thin films for optical and energy applications [9-10]. References [1] R. Liu et al., Chem. Commun., 2011, 47, 1384 [2] F. A. Cotton, Inorg. Chem., 1964, 3, 1217 [3] A. Perrin et al., C. R. Chimie, 2012, 15, 815 [4] Y. Luab et al., Chem. Soc. Rev., 2012, 41, 3594 [5] V. Fedorov, J. Clust. Sci., 2015, 26, 3 [6] S. Cordier et al., J. Inorg. Organomet. Polym., 2015, 25 189 [7] F. Grasset et al., Adv. Mater., 2008, 20, 1710 [8] T.K.N Nguyen et al., ECS J. Solid State Sci. Technol., 2016, (10) R178-R186 [9] T. G. Truong et al., Sci. Technol. Adv. Mat., 2016, 17(1), 443 [10] A. Renaud et al., ChemistrySelect, 2016, 1, 228

Octahedral molybdenum cluster as a photoactive antimicrobial additive to a fluoroplastic

Finding methods that fight bacterial infection or contamination, while minimising our reliance on antibiotics is one of the most pressing needs of this century. Although the utilisation of UV-C light and strong oxidising agents, such as bleach, are still efficacious methods for eliminating bacterial surface contamination, both methods present severe health and/or environmental hazards. Materials with intrinsic photodynamic activity (i.e. a material's ability upon photoexcitation to convert molecular oxygen into reactive oxygen species such as singlet oxygen), which work with light within the visible photomagnetic spectrum could offer a significantly safer alternative. Here we present a new, bespoke molybdenum cluster (Bu4N)2[Mo6I8(n-C7F15COO)6], which is both efficient in the generation of singlet oxygen upon photoirradiation and compatible with the fluoropolymer (F23-L) known for its good oxygen permeability. Thus, (Bu4N)2[Mo6I8(n-C7F15COO)6]/F23-L mixtures have been solution-processed to give homogenous films of smooth and fibrous morphologies and which displayed high photoinduced antibacterial activity against four common pathogens under visible light irradiation. These materials thus have potential in applications ranging from antibacterial coatings to filtration membranes and air conditioners to prevent spread of bacterial infections

Synthesis and physical properties of unsymmetric main-chain liquid crystal elastomers

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Flexible and Transparent Luminescent Cellulose-Transition Metal Cluster Composites

International audienceRed-NIR luminescent polymers are principally obtained from petroleum-based derivatives in which emitters, usually a critical raw material such as rare-earth or platinum group metal ions, are embedded. Considering the strong ecological impact of their synthesis and the major risk of fossil fuel energy shortage, there is an urgent need to find alternatives. We describe a luminescent nanocomposite based on red-NIR phosphorescent molybdenum nanoclusters, namely Cs(2)Mo(6)I(8)(OCOC(2)F(5))(6), embedded in an eco-friendly cellulose biopolymer matrix that is obtained by a simple solvent casting technique. While homogeneity is kept up to 20 wt% of cluster complex doping, annealing hybrids leads to a large increase of their emission efficiency, as demonstrated by quantum yield measurements