Collision‐induced dissociation of MCl + adducts (M = Mg, Mn, Zn, Co, Ni and Cu) and Cu + and Ag + adducts of dithioalkyl ketene acetals

Electrospray ionization mass spectra of equimolar solutions of dithioalkyl ketene acetals 1 and 2 and metal chlorides (MgCl 2 , MnCl 2 , ZnCl 2 , CoCl 2 , NiCl 2 and CuCl 2 ) produced abundant ligated metal ion adducts [ 1  + MCl] + and [ 2  + MCl] + . In addition, CuCl 2 also gave rise to Cu + adducts. The ligated metal ion adducts upon collision‐induced dissociation (CID) showed characteristic fragmentation pathways reflecting the favoured site of coordination. The results show that MgCl + prefers oxygen over sulfur, whereas the reverse is true for ZnCl + adducts, exemplified by the preferred fragmentation of [ 1  + MgCl] + as elimination of MgCl(OH), while that of [ 1  + ZnCl] + is expulsion of ZnCl(SCH 3 ). Co and Ni chloride adducts tend to give stable metal coordinated species. Cleavage of the dithiolane ring followed by elimination of C 2 H 4 S is the preferred pathway during the CID of [ 2  + MCl] + adducts. The CuCl + adducts of 1 and 2 showed reduction of Cu (I) to Cu (0) resulting in the M +· ions of 1 and 2 . Abstraction of . CH 3 resulting in elimination of CuCH 3 was observed during CID of Cu + adducts of 1 and 2 . A comparative study of the corresponding Ag + adducts revealed a similar behaviour. Copyright © 2001 John Wiley & Sons, Ltd.