Dendrimers are branched polymers that can be tuned for size, shape, andfunctionality. This relatively new class of compound has shown potential for useful host-guest chemistries including site-specific drug delivery via molecular recognition, catalysis, and nonlinear optics. Gas-phase dissociation studies have been initiated to probe the structure and stability of the half and first generation polypropylene dendrimer complexes and to develop an analytical framework for their characterization. These dissociation studies result in fragmentation products of mass-to-charge ratios that can be assigned to multiple possible isomers formed by potentially competing mechanisms. Since these reactions are under kinetic control we will present  theoretical density functional results for modeling the dissociation mechanisms for the most abundantly produced fragments from the protonated dendrimers. Several functionals in conjunction with a moderately-sized basis has been chosen for their utility in determining transition state energies and kinetic parameters. A novel proton-switching mechanism will be presented for these fragmentations.

DFT comparison of the fragmentation pathways of first generation protonated  nitrile and amine terminated PPI dendrimers

243rd National Meeting (2012)

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