FRAGMENTATION OF COLLISIONALLY ACTIVATED HYDROXYPHENOXIDE ANIONS IN THE GAS-PHASE

Low-energy collisionally activated dissociation of O-deprotonated dihy droxybenzenes (catechol, resorcinol, hydroquinone) in the gas phase ca uses both fragmentation to form [C6H4O2]- ions by loss of the remainin g oxygen-bound hydrogen atom and intramolecular hydrogen atom migratio n from 0 to C. The rearranged anions then undergo ring-cleavage reacti ons which are different in each case. Both catechol and hydroquinone p roduce fragments which are the result of the loss of two carbon atoms and both oxygen atoms but the proposed mechanisms are different. Resor cinol also produces a fragment which derives from the loss of carbon d ioxide. For this process a mechanism is proposed which involves a 6-me thylpyranone anion intermediate.