M II (qpy)(H 2 O) 2 ] 2+ (M = Fe, Co; qpy: 2,2′:6′,2″:6″,2‴-quaterpyridine) complexes efficiently catalyze the electrochemical CO 2 -to-CO conversion in acetonitrile solution in the presence of weak Bronsted acids. Upon performing cyclic voltammetry studies, controlled-potential electrolysis, and spectroelectrochemistry (UV−visible and infrared) experiments together with DFT calculations, catalytic mechanisms were deciphered. Catalysis is characterized by high selectivity for CO production (selectivity >95%) in the presence of phenol as proton source. Overpotentials as low as 240 and 140 mV for the Fe and Co complexes, respectively, led to large CO production for several hours. In the former case, the one-electron-reduced species binds to CO 2 , and CO evolution is observed after further reduction of the intermediate adduct. A deactivation pathway has been identified, which is due to the formation of a Fe 0 qpyCO species. With the Co catalyst, no such deactivation occurs, and the doubly reduced complex activates CO 2 . High scan rate cyclic voltammetry allows reaching kinetic conditions, leading to scan-rate-independent plateau-shaped voltammograms from which catalytic rate constant was obtained. The molecular catalyst is very active for CO production (turnover a frequency of 3.3 × 10 4 s −1 at 0.3 V overpotential), as confirmed by catalytic a Tafel plot showing a comparison with previous catalysts.

Achieving visible-light-driven carbon dioxide reduction with high selectivity control and durability while using only earth abundant elements requires new strategies. Hybrid catalytic material was prepared upon covalent grafting a Co−quaterpyridine molecular complex to semiconductive mesoporous graphitic carbon nitride (mpg-C 3 N 4) through an amide linkage. The molecular material was characterized by various spectroscopic techniques, including XPS, IR, and impedance spectroscopy. It proved to be a selective catalyst for CO production in acetonitrile using a solar simulator with a high 98% selectivity, while being remarkably robust since no degradation was observed after 4 days of irradiation (ca. 500 catalytic cycles). This unique combination of a selective molecular catalyst with a simple and robust semiconductive material opens new pathways for CO 2 catalytic light-driven reduction.

The photophysical, electrochemical, and optoelectronic properties of conjugated systems incorporating dibenzophosphole or phosphole moieties are described. Dibenzophosphole derivatives are not suitable materials for OLEDs due to their weak photoluminescence (PL) in the solid state and the instability of the devices. Variation of the substitution pattern of phospholes and chemical modification of their P atoms afford thermally stable derivatives, which are photo- and electroluminescent. Comparison of the optical properties of solution and thin film of thioxophospholes shows that these compounds do not form aggregates in the solid state. This property, which is also supported by an X-ray diffraction study of three novel derivatives, results in an enhancement of the fluorescence quantum yields in the solid state. In contrast, (phosphole)gold(I) complexes exhibit a broad emission in thin film, which is due to the formation of aggregates. Single- and multilayer OLEDs using these P derivatives as the emissive layer have been fabricated. The emission color of these devices and their performances vary with the nature of the P material. Interestingly, di(2-thienyl)thiooxophosphole is an efficient host for the red dopant DCJTB, and devices using the gold complexes have broad emission spectra.

Due to the continuously increasing demand for ultimate miniaturization of electronic and photonic systems, molecular electronics and plasmonic devices are currently booming as alternative technologies because of their very promising potential in writing, reading, storing, and processing information at the nanoscale. Conducting polymers or oligomers have been proposed and used as basic building blocks in molecular and plastic electronics since the end of the 80s. Plasmonics is, on the other hand, an emerging branch of photonics which uses nanostructured materials that support surface plasmons. Among plasmonic devices, active plasmonic devices are still lacking. In this work, we report on new active molecular plasmonic devices in which the electrochemical switching of a nanometric film of conductive polymer between its reduced and oxidized state is used in order to control, switch, and modulate localized surface plasmon (LSP) resonance of gold nanoparticle arrays.

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Exploiting the reactivity of the P-atom of phosphole-based oligomers, we have achieved access to the first organophosphorus-containing organic light-emitting diode (OLED) materials. The versatility of these P-materials is demonstrated with the synthesis of a corresponding gold complex that has also been used as an OLED material. Optimization of the OLED devices by doping the phosphole layer with a red fluorescent dye is described.

Control of the optical properties of oblate metallic nanoparticles (NP) is realized using an electrochemical switch consisting of a thin layer of conducting polymer (CP). Reversible modulation, moderate damping, and almost total quenching of the localized surface plasmon (LSP) resonance is achieved as a function of the thickness of the CP layer and the potential applied to the electrochemical systems, that is, the charge carrier density injected into the CP layer. These experimental results can be qualitatively reproduced using the single-particle model in the electrostatic approximation. We believe that combining an electroactive conducting polymer and NP will prove to be a general strategy for controlling the properties of various types of NP (fluorescent, magnetic, semiconducting) in many fields.

A new electrochemical methodology is reported for monitoring in homogeneous solution the enantiospecific binding of a small chiral analyte to an aptamer. The principle relies on the difference of diffusion rates between the targeted molecule and the aptamer/target complex, and thus on the ability to more easily electrochemically detect the former over the latter in a homogeneous solution. This electrochemical detection strategy is significant because, in contrast to the common laborious and time-consuming heterogeneous binding approaches, it is based on a simple and fast homogeneous binding assay which does not call for an aptamer conformational change upon ligand binding. The methodology is here exemplified with the specific chiral recognition of trace amounts of l- or d-tyrosinamide by a 49-mer d- or l-deoxyribooligonucleotide receptor. Detection as low as 0.1% of the minor enantiomer in a nonracemic mixture can be achieved in a very short analysis time (<1 min). The assay finally combines numerous attractive features including simplicity, rapidity, low cost, flexibility, low volume samples (few microliters), and homogeneous format.