| Abstract
| - The rate constants for bond shift (kBS) and intramolecular charge transfer (kCT) in alkali metal saltsof bicyclooctatetraenyl dianions (12-) in THF-d8 were determined by dynamic NMR spectroscopy. The valuesof kBS and kCTincrease in the order K < Na ≤ Rb < Cs and K < Rb < Na < Cs ≪ Li, respectively. It isconcluded that the K, Rb, and Cs salts react as contact ion pairs (CIPs) while the Li and Na salts react assolvent-separated ion pairs (SSIPs). Increases in kBS and kCT are observed in 12-/2K+ on going to more polarsolvents (NH3/CH3NH2 and THF-d8/DMEU). Comparison with kinetic studies of four other dianions has ledto the conclusion that 12-/2Na+ is the first example of a Na salt of a dianion to undergo charge transfer bySSIPs. This is attributed to the difficulty in forming a Na-bridged CIP transition structure in 12-/2Na+ thatcan compete with an SSIP transition structure.
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