NOBr

Nitrosyl bromide (NOBr) is a nitrosyl halide consisting of a nitrosyl (NO) moiety bonded to bromine. It is a highly reactive, moisture-sensitive compound that exists mainly as a short‑lived gas or in dry solutions at low temperature.

Preparation and occurrence: NOBr is typically generated in situ in dry solvents under inert atmosphere by reacting appropriate nitrosyl sources with brominating agents or bromine under controlled conditions. Due to its reactivity and tendency to hydrolyze, isolating pure, stable NOBr is challenging, and it is often used immediately after generation.

Properties and reactivity: NOBr functions as a nitrosating agent, capable of transferring the NO+ group to nucleophiles such as amines to form N-nitrosamines under suitable conditions. It hydrolyzes readily in water to form nitrous acid (HNO2) and hydrobromic acid (HBr). In organic synthesis, it is employed to introduce nitroso functionality into substrates and participates in reactions characteristic of nitrosyl halides, including various electrophilic and radical processes.

Applications: In chemical research, NOBr is used as a reagent for nitrosation and for generating other nitrosyl compounds. Its high reactivity and instability mean it is typically used in situ rather than as a storable material, contributing to studies in nitrogen-oxide chemistry and related areas.

Safety: NOBr is toxic and corrosive, with potential to release NO and other hazardous species. It is moisture sensitive and reacts with water to form acidic byproducts. Handling requires a fume hood, dry inert atmosphere, and appropriate personal protective equipment. Proper storage emphasizes protection from moisture and light and typically involves short-term use or immediate utilization after generation.