Abstract : We built a broadband Electron Paramagnetic Resonance (EPR) spectrometer capable of field- and frequency sweep experiments under field-, microwave amplitude- and microwave frequency-modulation detection modes (HM, AM, and FM, respectively). The spectrometer is based on a coplanar waveguide (CPW) architecture, with the sample being deposited on top of the transmission line. We tested...[En savoir plus]
Abstract : Recent reports have identified Cp*Co-based complexes to be powerful catalysts for aromatic C–H bond activation under oxidative conditions. However, little is known about the speciation of Cp*Co species during catalysis. We now show that key intermediates, Cp*CoIII metallacycles derived from 2-phenylpyridine (phpy-H), react swiftly in solution with one-electron oxidants to irreversibly...[En savoir plus]
Abstract Silicon vacancy (VSi) color centers in bulk SiC are excellent electron spin qubits. However, most spin based quantum devices require shallow spin qubits, whose dynamics is often different from that of bulk ones. Here, we demonstrate (i) a new method for creating shallow VSi (V2) spin qubits below the SiC surface by low energy ion implantation through a sacrificial SiO2 layer, (ii) that...[En savoir plus]
Abstract : Single-molecule junctions (SMJs) have been fabricated using layers generated by diazonium electroreduction. This process creates a C–Au covalent bond between the molecule and the electrode. Rigid oligomers of variable length, based on porphyrin derivatives in their free base or cobalt complex forms, have been grafted on the surface. The conductance of the oligomers has been studied by...[En savoir plus]
Abstract : Quantum embedding based on the (one-electron-reduced) density matrix is revisited by means of the unitary Householder transformation. While being exact and equivalent to (but formally simpler than) density matrix embedding theory (DMET) in the noninteracting case, the resulting Householder-transformed density matrix functional embedding theory (Ht-DMFET) preserves, by construction,...[En savoir plus]
Summary : Gold(I) catalysts enable the chemoselective addition of tailor-made N-sulfonylated azetidine derivatives onto alkynes, affording bicyclic vinyl-ammonium gold intermediates. Intramolecularly intercepted by an adequately positioned nucleophilic carbonate or ester function, these ammoniums efficiently lead to ring-expanded azepine products, which are important pharmacophore fragments....[En savoir plus]
Abstract : Chalcogen bonding results from non-covalent interaction occurring between electrodeficient chalcogen atoms and Lewis bases. Among the chalcogens, tellurium is the strongest Lewis acid but Te-based compounds are scarcely used as organocatalyst. For the first time, telluronium cations demonstrated impressive catalytic property at low loading in three benchmark reactions: the...[En savoir plus]