Archépolis. Archéologie et histoire de l’espace public à Thasos

Données scientifiques produites : WebSIG de ThasosGuillaume Biard, Julien Fournier, Marjolaine Imbs, « L’autel des Césars sur l’agora de Thasos », BCH 142, 2018, p. 725‑769Natacha Trippé, « Nouvelles recherches sur l’agora de Thasos : de la topographie à l’histoire », BCH 143.1, 2019, p. 195-224 Natacha Trippé, Marjolaine Imbs, « L’autel du sanctuaire de Zeus sur l’agora de Thasos », BCH 145.2, 2021, p. 15-41. Natacha Trippé, « L’articulation de l’espace religieux et de l’espace civique : l’..

Tetrathiafulvalene-Based Architectures: From Guests Recognition to Self-Assembly

The tetrathiafulvalene (TTF) unit has been successfully used for an incredibly broad range of applications. Beyond the well-established conducting properties of the corresponding cation-radical salts, this unit has appeared as a key redox-active component for various applications supported by its remarkable redox properties: a high π-donating ability and occurrence of three stable redox states. This article reviews the main contribution of the group of Angers to this field, highlighting results obtained in terms of redox-sensing as well as efforts carried out to reach new self-assembled TTF-based architectures

4,6,7,9,10,12-Hexahydro-1,3-dithiolo[4,5-f][1,4,9]oxadithia­cyclo­undecine-2-thione

In the title mol­ecule, C9H12S5O, the five-membered ring and attached S atom are essentially coplanar [mean deviation from the mean plane = 0.020 (1) Å]. The two S atoms belonging to the macrocycle deviate from this plane by 1.005 (1) and 1.337 (2) Å. In the crystal, π–π inter­actions link the mol­ecules into centrosymmetric dimers with a short distance of 3.753 (5) Å between the centroids of the five-membered rings

Methyl 2,3-(3,6,9-trioxaundecane-1,11-diyldithio)-1,4,5,8-tetra­thia­fulvalene-6-carboxyl­ate

In the title mol­ecule, C16H20O5S6, the two five-membered rings form a dihedral angle of 4.7 (3)°. The crystal packing exhibits weak inter­molecular C—H⋯O hydrogen bonds, which link the mol­ecules into chains propagating in [10], and π–π inter­actions, indicated by the short distances [3.756 (5) Å] between the centroids of five-membered rings from mol­ecules related by translation along the b axis

An extended tetrathiafulvalene redox-ligand incorporating a thiophene spacer

An extended tetrathiafulvalene derivative incorporating a thiophene spacer and a fused crown-ether unit has been synthesized. This highly delocalized system exhibits remarkable electrochemical recognition properties for Na+ and Ba2+ as shown by cyclic voltammetry in methylene chloride. This result is attributed to the proximity between the guest metal cation and the positive charge of the oxidized ligand, which is located on the central conjugated thiophenic part

Taming Friedrich-Wintgen interference in resonant metasurface: vortex laser emitting at on-demand tilted-angle

Friedrich-Wintgen (FW) interference is an atypical coupling mechanism that grants loss exchange between leaky resonances in non-Hermitian classical and quantum systems. Intriguingly, such an mechanism makes it possible for destructive interference scenario in which a radiating wave becomes a bound state in the continuum (BIC) by giving away all of its losses. Here we propose and demonstrate experimentally an original concept to tailor FW-BICs as polarization singularity at on-demand wavevectors in optical metasurface. As a proof-of-concept, using hybrid organic-inorganic halide perovskite as active material, we empower this novel polarization singularity to obtain lasing emission exhibiting both highly directional emission at oblique angles and polarization vortex in momentum space. Our results pave the way to steerable coherent emission with tailored polarization pattern for applications in optical communication/manipulation in free-space, high-resolution imaging /focusing and data storage

Multinuclear NMR as a tool for studying local order and dynamics in CH3NH3PbX3 (X = Cl, Br, I) hybrid perovskites

International audienceWe report on Pb, Br, N, H, C and H NMR experiments for studying the local order and dynamics in hybrid perovskite lattices. Pb NMR experiments conducted at room temperature on a series of MAPbX compounds (MA = CHNH; X = Cl, Br and I) showed that the isotropic Pb NMR shift is strongly dependent on the nature of the halogen ions. Therefore Pb NMR appears to be a very promising tool for the characterisation of local order in mixed halogen hybrid perovskites. Pb NMR on MAPbBrI served as a proof of concept. Proton, C and N NMR experiments confirmed the results previously reported in the literature. Low temperature deuterium NMR measurements, down to 25 K, were carried out to investigate the structural phase transitions of MAPbBr. Spectral lineshapes allow following the successive phase transitions of MAPbBr. Finally, quadrupolar NMR lineshapes recorded in the orthorhombic phase were compared with simulated spectra, using DFT calculated electric field gradients (EFG). Computed data do not take into account any temperature effect. Thus, the discrepancy between the calculated and experimental EFG evidences the fact that MA cations are still subject to significant dynamics, even at 25 K