Dissecting the Flash Chemistry of Electrogenerated Reactive Intermediates by Microdroplet Fusion Mass Spectrometry

A novel mass spectrometric method for probing the flash chemistry of electrogenerated reactive intermediates was developed based on rapid collision mixing of electrosprayed microdroplets by using a theta-glass capillary. The two individual microchannels of the theta-glass capillary are asymmetrically or symmetrically fabricated with a carbon bipolar electrode to produce intermediates in situ. Microdroplets containing the newly formed intermediates collide with those of the invoked reactants at sub-10 microsecond level, making it a powerful tool for exploring their ultrafast initial transformations. As a proof-of-concept, we present the identification of the key radical cation intermediate in the oxidative dimerization of 8-methyl-1,2,3,4-tetrahydroquinoline and also the first disclosure of previously hidden nitrenium ion involved reaction pathway in the C-H/N-H cross-coupling between N,N '-dimethylaniline and phenothiazine.

Automated summary

A novel mass spectrometric method was developed to probe the flash chemistry of electrogenerated reactive intermediates through rapid collision mixing of electrosprayed microdroplets. This method allows for fast identification and exploration of ultrafast initial transformations in the reaction process.