17th International Mass Spectrometry Conference :: Prague, 2006
> Go to contents (site navigation)
|Session:||LATE-BREAKING/Gas Phase Ion Chemistry|
|Presentation date:||Tue, Aug 29, 2006|
|Presentation time:||14:30 – 16:00|
Ruth Mary Burke1, William Edward Boxford1, Caroline E. H. Dessent11 University of York, York, United Kingdom
Correspondence address: Ruth Mary Burke, University of York, Chemistry, Heslington, York, YO10 5DD United Kingdom.
Keywords: Collision Induced Dissociation (CID)/Collision Activated; Electrospray Ionization (ESI); Negative Ion; Salts.
Novel aspect: The first application of ESI-MS and resonance excitation within a quadrupole ion-trap to explore the ground-state potential energy surfaces of contact ion-pair complexes that contain multiply charged anions (MCAs).
We report the first application of ESI-MS and resonance excitation within a quadrupole ion-trap to explore the ground-state potential energy surfaces of contact ion-pair complexes that contain multiply charged anions (MCAs). Low energy excitation of model systems such as K+·Pt(CN)42- and K+·Pt(CN)62- results in fragmentation products associated with decay of the isolated constituent dianions, revealing that the ground state ion-pair surfaces are dominated by the intrinsic characteristics of the MCA. This observation is important since it indicates that counter-ion complexation only weakly perturbs the electronic structure of an MCA, and that the cation-dianion clusters can therefore accurately be described as isolated ion-pair complexes.
For K+·Pt(CN)42-, where the Pt(CN)42- dianion decays with production of two ionic fragments, we observe evidence for the existence of a novel exit-channel complex corresponding to a polar KCN salt unit bound to the Pt(CN)3- anion. Further results are presented for a series of gas-phase cation-dianion clusters, e.g. M+·Pt(CN)62-, M+·Pd(CN)42-, and M+·PtCl62- (where M= Na, K, Rb), to illustrate their generality. Density functional theory calculations are also presented to support the experimental results.
The results described provide a basis for understanding the potential energy surfaces and fragmentation characteristics of other ion-pair complexes that involve MCAs. Such species represent important features of the ESI-MS of common biomolecular ions. Towards this goal, we present new results extending our work to larger, more flexible systems such as K+·H3P3O102- and counter-ion complexes of Adensoine 3'-triphosphate.