We have performed NMR linebroadening and stopped-flow kineticstudies of the rates of both true- and pseudo- electron-transfer self-exchangereactions of rutheniumpentaamminepyridyl complexes of the formulation (NH3)5Ru(II/III)(pyX)2+/3+where pyX represents a range of variously substituted pyridine ligands.  Expected behaviors such as rate vs. driving force for the pseudo-selfexchange reactions and near-constancy of rate with pyX for the true self-exchangerates (NMR) were generally observed, but there were notable exceptions forcomplexes bearing both the 3-phenylpyridine and 4-phenylpyridine ligands.  The clear rate acceleration for these complexes is most likely due to favorable p- p stacking type interactions in the encounter complex.  It is unclear at this point whether the acceleration arises from a simple increase in the bimolecular association constant to form the encounter complex, or if it is due to enhanced electronic coupling relative to the other substituted pyridines studied.

Bimolecular electron-transfer rate enhancement due to Pi-stacking type interactions in the encounter complex between ruthenium pentaammine pyridyl complexes in aqueous solution specific to 3- and 4-phenylpyridine ligands

239th National Meeting (2010)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.