We introduce the novel fluoroalkoxy molybdenum(V) reagent 1 which has superior reactivity and selectivity in comparison to MoCl5 or the MoCl5 /TiCl4 reagent mixture in the oxidative coupling reactions of aryls. Common side reactions, such as chlorination and/or oligomer formation, are drastically diminished creating a powerful and useful reagent for oxidative coupling. Theoretical treatment of the reagent interaction with 1,2-dimethoxybenzene-type substrates indicates an inner-sphere electron transfer followed by a radical cationic reaction pathway for the oxidative-coupling process. EPR spectroscopic and electrochemical studies, X-ray analyses, computational investigations, and the experimental scope provide a highly consistent picture. The substitution of chlorido ligands by hexafluoroisopropoxido moieties seems to boost both the reactivity and selectivity of the metal center which might be applied to other reagents as well.

The oxidative cyclization reaction of 2-aryl cinnamates and derivatives thereof can be easily performed with MoCl5 as the oxidant. This powerful reagent allows oxidative coupling reactions for which other reagents fail. The best results are obtained when the 2-phenyl substituent of the cinnamate is equipped with two methoxy groups. Even iodo moieties in the bay region of phenanthrene are tolerated under the reaction conditions. If naphthalene moieties are involved, a rearrangement of the skeleton occurs, providing an elegant route to highly functionalized angular arenes. The cyclization is demonstrated for 15 example substrates with isolated yields of up to 99 % for the phenanthrene derivative. The broad scope of the reaction underlines the usefulness of MoCl5 and MoCl5 /TiCl4 in the oxidative coupling reaction.

The oxidative treatment of (m)ethyl 2‐aryl cinnamates equipped with methoxy groups in position 4 of the phenyl moiety promote the formation of cyclohexadienone substructures. This dealkylative oxidative C–C coupling gives access to spirocyclic compounds and avoids the construction of the corresponding phenanthrenes. Furthermore, the transformation can be expanded to other spirocyclic systems.

Protonated species of the nucleobase cytosine (C), namely the monoprotonated CH+ and the hemiprotonated CHC+, were used to obtain four charge‐transfer complexes of [Ni(dmit)2] (dmit: 1,3‐dithiole‐2‐thione‐4,5‐dithiolate). Diffusion methods afforded two semiconducting [Ni(dmit)2]− salts; (CH)[Ni(dmit)2](CH3CN) (1) and (CHC)[Ni(dmit)2] (2). In salt 1, the [Ni(dmit)2]− ions with a S=1/2 spin construct a uniform one‐dimensional array along the molecular long axis, and the significant intermolecular interaction along the face‐to‐face direction results in a spin‐singlet ground state. In contrast, salt 2 exhibits the Mott insulating behavior associated with uniform 1D arrays of [Ni(dmit)2]−, which assemble a two‐dimensional layer that is sandwiched between the layers of hydrogen‐bonded CHC+ ribbons. Multiple hydrogen bonds between CHC+ and [Ni(dmit)2]− seem to result in the absence of structural phase transition down to 0.5 K. Electrooxidation of [Ni(dmit)2]− afforded the polymorphs of the [Ni(dmit)2]0.5− salts, (CHC+)[{Ni(dmit)2}0.5−]2 (3 and 4), which are the first mixed‐valence salts of nucleobase cations with metal complex anions. Similar to 2, salt 3 contains CHC+ ribbons that are sandwiched between the 2D [Ni(dmit)2]0.5− layers. In the layer, the [Ni(dmit)2]0.5− ions form dimers with a S=1/2 spin and the narrow electronic bandwidth causes a semiconducting behavior. In salt 4, the CHC+ units form an unprecedented corrugated 2D sheet, which is sandwiched between the 2D [Ni(dmit)2]0.5− layers that involve ring‐over‐atom and spanning overlaps. In contrast to 3, salt 4 exhibits metallic behavior down to 1.8 K, associated with a wide bandwidth and a 2D Fermi surface. The ability of hydrogen‐bonded CHC+ sheets as a template for the anion radical arrangements is demonstrated.

Powerful Fluoroalkoxy Molybdenum(V) Reagent for Selective Oxidative Arene Coupling Reaction. -A novel dinuclear fluoroalkoxy Mo(V)-complex is efficient as reagent for the oxidative arene coupling of electron-rich arenes with superior reactivity compared to MoCl 5 and MoCl5/TiCl4. -(SCHUBERT, M.; LEPPIN, J.; WEHMING, K.; SCHOLLMEYER, D.; HEINZE, K.; WALDVOGEL*, S. R.; Angew. Chem., Int. Ed. 53 (2014) 9, 2494-2497, http://dx.