A ‘Defective’ Conjugated Porous Poly-Azo as Dual Photocatalyst

A heterogeneous photocatalyst amenable to catalyze different chemical reactions is a highly enabling and sustainable material for organic synthesis. Herein we report the synthesis and characterization of an azobenzene-based organic π–conjugated porous polymer (AzoCPP) as heterogeneous dual photocatalyst manifesting net-oxidative bromination of arenes and dehydroxylation of boronic acids to corresponding phenols. Hierarchical porosity and high surface area of the nano-sized AzoCPP allowed superior catalyst-substrate contact during catalyses, whereas the inherent structural defect present in the CPP backbone resulted in low-energy sinks functioning as de facto catalytic sites. A combination of these two structure-property aspects of AzoCPP, in addition to the dielectric constant manipulation of the system, led to excellent catalytic performance. The protocols remained valid for a wide substrate scope and the catalyst was recycled multiple times without substantial loss in catalytic activity. With the aid of subsequent control experiments and analytical characterizations, mechanisms for each catalysis are proposed and duly corroborated.

A Practical Procedure for Regioselective Bromination of Anilines

Highly practical procedure for the preparation of bromoanilines has been developed using copper-catalyzed oxidative bromination. Treatment of free anilines with readiliy available NaBr and Na₂S₂O₈ in the presence of catalytic amount of CuSO₄·5H₂O enabled their regioselective bromination.

Bioinspired catalysis and bromoperoxidase like activity of a multistimuli-responsive supramolecular metallogel: supramolecular assembly triggered by pi–pi stacking and hydrogen bonding interactions

We report the synthesis and characterization of a new self-assembled VO2-L metallogel. Multi-responsive properties of the gel were also studied and can be used for sensing OH− anions. Bromoperoxidase-like activity of VO2-L metallogel for oxidative bromination reaction was also reported.

A metal-free aerobic oxidative bromination of anilines and aryl ketones with 2-methylpyridinium nitrate as a reusable ionic liquid

An aerobic oxidative bromination of anilines and aryl ketones catalyzed by recyclable 2-methylpyridinium nitrate ionic liquid is achieved in water using hydrobromic acid as the bromine source and molecular oxygen as the oxidant. The catalytic system shows good efficiency and atom economy.