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Nitrenium ions are important reactive intermediates in chemistry and biology. In this work, femtosecond and nanosecond transient absorption (fs-TA and ns-TA) along with nanosecond time-resolved resonance Raman (ns-TR³) experiments were employed to examine the photochemical pathways of <i>N</i>-(4,4&#8242;-dibromodiphenylamino)-2,4,6-trimethylpyridinium BF₄^&#8722; (salt (DN) from just absorption of a photon of light to the production of the important <i>N</i>,<i>N</i>-di(4-bromophenyl)nitrenium ion <b>2</b>. In acetonitrile (MeCN), the formation of halogenated diarylnitrenium ion <b>2</b> was observed within 4 ps, showing the vibrational spectra with strong intensity. The nucleophilic adduct reaction of ion <b>2</b> with H₂O was also examined in aqueous solutions. The direct detection of the unique ortho adduct intermediate <b>3</b> shows that there is an efficient and exclusive reaction pathway for <b>2</b> with H₂O. The results shown in this paper give new characterization of <b>2</b>, which can be used to design time-resolved spectroscopy investigations of covalent addition reactions of nitrenium ions with other molecules in future studies.