2.1 Chemicals and Reagents
Methanol and dichloromethane (DCM) were purchased from Merck KGaA (Darmstadt, Germany). All of the samples were provided by Jianwei Han research group at East China University of Science and Technology, Shanghai. The preparation methods could be referred to relevant articles.37-39 Some structures of the diaryliodonium salts (M ) were given in Scheme 2 , while the rest structures were shown in Scheme S1 , and they were labeled for convenience as 1 to 54 . Salts 24 , 33and 34 contained OTs as counter anion, the rest diaryliodonium salts contained OTf as counter anion. DCM was a suitable aprotic solvent for preparing the solution of diaryliodonium salts. In most cases, the diaryliodonium salts were dissolved in DCM to prepare the sample solution at concentration of 1~10 µg/mL for mass spectrometric analysis.
Scheme 2 Chemical structures of some diaryliodonium salts (1 ~16 ) in this study, Mes = mesitylene.