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A series of compact azobenzene derivatives were investigated as phase-transition molecular solar thermal energy storage compounds that exhibit maximum energy storage densities around 300 J g?1. The relative size and polarity of the functional g

Aromatic azo compounds, which play an important role in pharmaceutical and industrial applications, still face great challenges in synthesis. Herein, we report a molybdenum oxide compound, [N(C4H9)4]2[Mo6O19] (1), catalyzed selective oxidation of anilines with hydrogen peroxide as green oxidant. The oxidation of anilines can be realized in a fully selectively fashion to afford various symmetric/asymmetric azobenzene and azoxybenzene compounds, respectively, by changing additive and solvent, avoiding the use of stoichiometric metal oxidants. Preliminary mechanistic investigations suggest the intermediacy of highly active reactive and elusive Mo imido complexes.

A highly efficient, metal-free, chemical oxidation of hydrazines has been implemented using environmentally friendly TCCA as oxidant. This benign protocol provides straightforward access to a wide range of azo compounds in THF in excellent yield. Altogether, 35 azo compounds were obtained in this way and scale-up preparations were performed. Additionally, a plausible mechanism was also proposed. Step-economical process, mild reaction conditions, operational simplicity, high reaction efficiency, and easy scale-up highlight the practicality of this methodology.

A strategy for the electrochemical dehydrogenation of hydrazine compounds is disclosed under ambient conditions. This protocol proceeded smoothly in ethanol by employing electrons as clean oxidants. Its synthetic value is well demonstrated by the highly efficient synthesis of symmetric and unsymmetric azo compounds. It is an environmentally friendly transformation and the present protocol was effective on a large scale.

In this report, we describe the application of palladium-based oxidative addition complexes (OACs) as effective precatalysts for C-N, C-O, and C-F cross-coupling reactions with a variety of (hetero)arenes. These complexes offer a convenient alternative to previously developed classes of precatalysts, particularly in the case of the bulkiest biarylphosphine ligands, for which palladacycle-based precatalysts do not readily form. The precatalysts described herein are easily prepared and stable to long-term storage under air.

A novel strategy for the dehydrogenation of the NH?NH bond is disclosed using potassium tert-butoxide (tBuOK) in liquid ammonia (NH3) under air at room temperature. Its synthetic value is well demonstrated by the highly efficient synthesis of aromatic azo compounds (up to 100 % yield, 3 min), heterocyclic azo compounds, and dehydrazination of phenylhydrazine. The broad application of this strategy and its benefit to chemical biology is proved by a novel, convenient, one-pot synthesis of aliphatic diazirines, which are important photoreactive agents for photoaffinity labeling.

A straightforward palladium-catalyzed oxidative hydroxylation of azobenzenes is reported. The developed methodology tolerates various functional groups and allows the synthesis of diverse unsymmetrical azophenols under mild conditions in good to excellent yields. A complementary procedure was also investigated by in situ generation of PIFA. This study represents the first general method for the synthesis of o-hydroxyazobenzenes starting from simple azoarenes.

Pd(II)-catalyzed C-H sulfonylation of azobenzenes with arylsulfonyl chlorides has been developed. The sulfonylazobenzenes were obtained in moderate to excellent yields for 28 examples. This protocol features high efficiency, wide functional group tolerance, and atom economy.