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Steric Control of Electron Transfer. Changeover from Outer-Sphere to Inner-Sphere Mechanisms in Arene/Quinone Redox Pairs
| Content Provider | Semantic Scholar |
|---|---|
| Author | Hubig, Stephan M. Rathore, And Rajendra Kochi, Jay K. |
| Copyright Year | 1999 |
| Abstract | The various aromatic hydrocarbons (Chart 2) constitute a sharply graded series of sterically encumbered (unhindered, partially hindered, and heavily hindered) donors in electron transfer (ET) to quinones (Chart 1). As such, steric effects provide the quantitative basis to modulate (and differentiate) outer-sphere and inner-sphere pathways provided by matched pairs of hindered and unhindered donors with otherwise identical electron-transfer properties. Thus the hindered donors are characterized by (a) bimolecular rate constants (k2) that are temperature dependent and well correlated by Marcus theory, (b) no evidence for the formation of (discrete) encounter complexes, (c) high dependency on solvent polarity, and (d) enhanced sensitivity to kinetic salt effectsall diagnostic of outer-sphere electron-transfer mechanisms. Contrastingly, the analogous unhindered donors are characterized by (a) temperature-independent rate constants (k2) that are 102 times faster and rather poorly correlated by Marcus theory, (... |
| Starting Page | 617 |
| Ending Page | 626 |
| Page Count | 10 |
| File Format | PDF HTM / HTML |
| DOI | 10.1021/ja9831002 |
| Volume Number | 121 |
| Alternate Webpage(s) | http://www.mu.edu/chem/documents/38.pdf |
| Alternate Webpage(s) | https://doi.org/10.1021/ja9831002 |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |