Olivier Galangau

Université de Rennes 1 | UR1 · Institut des Sciences Chimiques de Rennes (ISCR) - UMR CNRS 6226

In this work, we report our latest results regarding the self‐assembly properties of two Ru‐acetylides complexes and their corresponding free organic ligands, in the solid and the solution states. The four compounds show mesogenic properties, which we have rationalized thanks to extensive DSC, SAXS, POM, FTIR and molecular dynamic investigations. W...

We report on the first systematic transport study of alkynyl-ended oligophenyl-diethynyl (OPA) single-molecule junctions with direct Au-C anchoring scheme at low temperature using the mechanically controlled break junction technique. Through quantitative statistical analysis of opening traces, conductance histograms and density functional theory st...

Metal complexes associated with photochromic molecules are attractive platforms to achieve smart light-switching materials with innovative and exciting properties due to specific optical, electronic, magnetic or catalytic features of metal complexes and by perturbing the excited-state properties of both components to generate new reactivity and pho...

Molecular luminescent switches form a unique and fascinating class of compounds which luminescence response can be toggled with chemical or physical stimuli. Switchable Near InfraRed (NIR) emitters are of major interest since they are compatible with in vivo imaging and have potential for advanced materials such as security tags. Of particular inte...

This work describes a class of complex combining three dithienylethene units and a lanthanide ion used as an optical system displaying a double encryption method: i) a colorful code, drawn and erased under UV and visible irradiations respectively, due to coloration and discoloration of the photochromic entities, and ii) a concomitant gradual disapp...

We report the synthesis of an original ligand scaffold based on a dimethyl-cyclen platform Medo2pa with two dithienylethene units attached to each picolinate arms and the corresponding yttrium(III), europium(III) and ytterbium(III) complexes. All three compounds show reversible photochromism with high photo-conversions. Photoluminescence experiment...

The two mononuclear complexes of the formula [Dy(tta)3(L)] (1) and [Dy(hfac)3(L)] (2) (where tta- = 2-thenoytrifluoroacetylacetonate and hfac- = 1,1,1,5,5,5-hexafluoroacetylacetonate) were obtained from the coordination reaction of the Dy(tta)3·2H2O or Dy(hfac)3·2H2O units with the 1,10-phenantroline-5,6-dione ligand (L). Their structures have been...

We report the synthesis of an original ligand scaffold based on a dimethyl-cyclen platform Medo2pa with two dithienylethene units attached to each picolinate arms and the corresponding yttrium(III), europium(III) and ytterbium(III) complexes. All three complexes show reversible photochromism with high photo-conversions. Photoluminescence experiment...

With the help of a judicious association between DTE units, an ytterbium ion and a ruthenium carbon-rich complex, we describe (i) the efficient (on/off) switching of pure NIR luminescence with a photochromic unit absorbing in the UV range, and (ii) the associa-tion of electrochemical and photochemical control of this NIR emission in a single system...

The reaction between the 2-(1-(4′-[4-(methylphenyl]-2,2:6′,2″-terpyridyl)-4,5-(4,5-bis(propylthio)-tetrathiafulvalenyl)-1H-benzimidazol-2-yl)-pyridine (L) and 2 equivalents of Dy(hfac) 3 ·2H 2 O (hfac ⁻ = 1,1,1,5,5,5-hexafluoroacetyacetonate) metallic precursors leads to the formation of a dinuclear complex of formula [Dy 2 (hfac) 6 (L)]·C 6 H 14 (...

The efficient switching that can occur between two stable isomers of diarylethenes makes them particularly promising targets for opto‐ and molecular electronics. To examine these classes of molecules for electronics applications, they have been subjected to a series of scanning tunneling microscopy (STM) experiments which are the focus of this Revi...

Tetrathiafulvalene and 1,10-phenanthroline moieties present, respectively remarkable redox-active and complexation activities. In this work, we investigated the coordination reaction between the bis(1,10-phenanthro[5,6-b])tetrathiafulvalene triad (L) and the Dy(hfac)3·2H2O metallo precursor. The resulting {[Dy2(hfac)6(L)]·CH2Cl2·C6H14}3 (1) dinucle...

A central issue in molecular electronics in order to build functional devices is to assess whether changes in the elec-tronic structure of isolated compounds by chemical derivatization are retained once the molecules are inserted into molecular junctions. Recent theoretical studies have suggested that this is not always the case due to the occurren...

This work reports synthesis and characterizations of two new electron-poor “oligo(phenyleneethynylene) (OPE) type” molecular wires for fundamental studies of electron transport in molecular junctions. These OPE derivatives display three aromatic rings functionalized (i) with NO2 (OPN) or fluorine (OPF) groups on the central aryl core and (ii) with...

Photoswitching materials are building blocks of next generation optoelectronic devices which may require molecule deposition on a solid substrate. However, molecule properties change upon adsorption due to surface-molecule interactions and symmetry considerations. Scanning tunneling microscopy (STM) and density functional theory (DFT) offer techniq...

Bottom-up approaches allow for molecular-level control of engineering new nanostructures. For the next generation molecular circuits, machines, and phase-change materials, supramolecular structure formation and interactions must be investigated on a two-dimensional solid substrate. Scanning tunneling microscopy (STM) provides not only a method to a...

In the field of extreme miniaturization of electronic devices, it is necessary to study candidate molecules at the single molecular level by scanning tunneling microscopy (STM). This necessitates molecules to harbor specific functionalization to control molecule-surface interactions to avoid molecular diffusion on the surface and molecule-molecule...

In this manuscript, we present a novel concept for “smarter” photo-labile organic compounds combining not one but two caged functions. As proof of principle, this diarylethene-based compound possesses two inhibited chemical groups (OMe and OAc) and its efficient release in different solvents is reported. In low to medium polar media, both MeOH and...

A series of highly sensitive neutral photoacid generators (PAGs) based on photochromic terarylenes was prepared. Like the example presented herein, these compounds show a subsequent thermal elimination of a Brønsted acid after a light-triggered 6π-electrocyclization, concomitant with the hexatriene aromatization. A novel type of molecular systems w...

Many nanomachines with controlled molecular motions have been studied, mainly on metallic surfaces, which are easy to obtain very clean, and are stable over months. However, the studies of mechanical properties of nanomachines are mainly performed at very low temperature (5 to 80K) which prevents any kind of applications. In this paper, we will pre...

The high reactivity of 6π-electrocyclization in polar solvents has remained one of the important challenges for diarylethenes because of the emergence of a twisted intramolecular charge transfer (TICT) state at the excited state in such polar media, which usually quenches the photocyclization reaction. Herein we report on the preparation and highly...

We herein propose a new type of efficient neutral photoacid genera-tor. A photoinduced 6-electrocyclization reaction of photochromic triangle terarylenes triggers subsequent release of a Brønsted acid, which took place from the photocyclized form. A hydrogen atom and its conjugate base were introduced at both sides of a 6-system to form the self-...

Five diarylethene photochromic derivatives, the structures of which incorporate a central benzothiophene unit, a left-hand thiazole group, and a right-hand benzothiophene group, have been prepared. The compound with a thiazole unit with no substituent on the reaction-center carbon atom reveals an unprecedented transformation upon light irradiation....

Photosensitivity of molecules is one of the central subjects of organic photochemistry. In this article, we present how and why a benzothiophene moiety impacts the photochromic quantum yield for the photochemical pericyclic ring closing of the hexatriene moiety. Two compounds were prepared: a symmetrical one incorporating two fluorenylthiophene uni...

A new synthesis of [3]ferrocenophan-1-one has been developed, and a Trofimov reaction has been applied to its ketoxime. The novel subsequent N-vinyl pyrrole ferrocenophane displays reversible electrochemical behavior centered on the ferrocene, without any participation of the pyrrole. Unexpected byproduct was also isolated, in which the α-pyrrolic...