The effect of counterion, solvent, and temperature on the proton nmr spectrum of the cyclononatetraenyl anion, cyclooctatetraene dianion, and tropylium cation have been investigated. In DME and THF, the lithium and sodium salts of the cyclononatetraenyl anion exist as an equilibrium mixture of contact and solvent-separated ion pairs whereas the potassium, rubidium, and cesium salts exist only as contact ion pairs. Salts of cyclooctatetrene dianion exist as contact ion pairs in all solvents examined. Lithium-7 nmr shifts support this view. The nmr spectrum of several tropylium salts shows the chemical shift of the tropylium cation to be independent of counterion but solvent dependent. These results suggest that the tropylium salts exist in solution as free solvated ions and solvent-separated ion pairs.

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