Description
9-Bromophenanthrene is a luminescent material that fluoresces at short wavelengths and can be used as a molecular probe to detect the presence of other compounds and the mechanism of reaction, among other things.
Chemical Properties
light yellow powder. soluble in toluene, and chloroform (50 mg/ml).
Uses
9-Bromophenanthrene is used as halogenated building block. Isotope labelled 9-Bromophenanthrene (B687200), a halogenated polycyclic aromatic hydrocarbon that has been seen to have a room temperature phosphorescence that can be induced by β-cyclodextrin (β-CD) in the presence of cyclohexane; however, trace Fe(III) causes a decrease of the RTP emission.
Preparation
9-Bromophenanthrene (90-94%) is produced by adding bromine to a refluxing solution of phenanthrene in carbon tetrachloride. This is the starting-point of 9-substituted phenanthrenes, e.g, when heated with cuprous cyanide at 260℃, 9-bromophenanthrene forms the corresponding cyano-compound; this may be hydrolysed to phenanthrene-9-carboxylic acid. Phenanthrene undergoes the Friedel-Crafts reaction mainly in the 3-, and to a small extent, in the 2-position. It is chloromethylated in the 9-position. When nitrated, phenanthrene gives a mixture of three mononitro-derivatives, the 3-isomer predominating. Sulphonation of phenanthrene gives a mixture of 1-, 2-, 3- and 9-phenanthrenesulphonic acids, and the ratio of these isomers depends on the temperature.
Synthesis
The general procedure for the synthesis of 9-bromophenanthrene from phenanthrene was as follows: a 50 mL round-bottomed flask was charged with a magnetic stirrer, followed by the addition of a solvent mixture of acetic acid and water (9:1, 10 mL, by volume). Phenanthrene (514 mg, 2 mmol) and potassium bromide (215 mg, 1.8 mmol) were added sequentially to the flask and allowed to dissolve completely under magnetic stirring. Zinc-aluminum bromate layered double hydroxide (ZnAl-BrO3-LDH, 1.2 g, containing 1.2 mmol BrO3) was added slowly in batches over a period of half an hour, and the reaction temperature was maintained at 40 °C with continuous stirring for 4 hours. The progress of the reaction was monitored by thin-layer chromatography (TLC) during the reaction using ethyl acetate and petroleum ether (1:15, v/v) as the unfolding agent. Upon completion of the reaction, the reaction mixture was extracted with dichloromethane (3 × 10 mL), and the combined organic phases were washed with distilled water (3 × 10 mL). The organic phase was dried over anhydrous sodium sulfate and filtered, and purified by column chromatography (eluent ratio of petroleum ether to ethyl acetate 15:1, v/v) to obtain the final white crystalline product in 91% yield.
References
[1] Organic Letters, 2003, vol. 5, # 18, p. 3317 - 3319
[2] Journal of Organic Chemistry, 1988, vol. 53, # 9, p. 2093 - 2094
[3] Phosphorus, Sulfur and Silicon and the Related Elements, 2005, vol. 180, # 2, p. 533 - 536
[4] Patent: CN107151197, 2017, A. Location in patent: Paragraph 0018; 0019; 0021-0024; 0025-0028
[5] Bulletin of the Chemical Society of Japan, 1994, vol. 67, # 7, p. 1918 - 1921
