ION-ION REACTIONS IN THE GAS-PHASE - PROTON-TRANSFER REACTIONS OF PROTONATED PYRIDINE WITH MULTIPLY-CHARGED OLIGONUCLEOTIDE ANIONS

Isolated triply and doubly charged anions of the single-stranded deoxy nucleotide 5'-d(AAAA)-3' were allowed to undergo ion-ion proton transf er reactions with protonated pyridine cations within a quadrupole ion trap mass number densities and spatial overlap of the oppositely charg ed ion clouds could be achieved to yield readily measurable rates. Thr ee general observations were made: (1) the ion-ion reaction rate const ants were estimated to be 10(-(7-8)) cm(3) ion(-1) s(-1); (2) the ion- ion reaction rates were found to be dependent on the reactant ion numb er density, which could be controlled by both the reactant ion number and the pseudopotential well depth, and (3) very little fragmentation, if any, was observed, as might normally be expected with highly exoth ermic proton transfer reaction.