Complexation of cyclic polyethers of the "crown" type to ion pairs of fluorenyl alkali salts was studied in ethereal solvents and pyridine by nmr and by uv-visible spectroscopy. The absorption spectra of these complexes are identical with the spectra of the solvent-separated ion pairs of the fluorenyl alkali salts. The complexing with the ion pairs leads to strong upfield shifts in the nmr spectrum of the polyether ring protons. The binding of fluorenylsodium with dimethyldibenzo-18-crown-6 is so strong that a slow exchange process with free cyclic polyether is observed, with an activation energy of 12.5 kcal/mole. The selectivity of this particular cyclic polyether with respect to alkali ions in THF was found to be Na+ » K+ > Cs+ > Li+, but this sequence is dependent on the solvent medium. In oxetane, the cyclic polyether prefers the fluorenylpotassium above the sodium salt. The complexing with some other cyclic polyethers was also investigated.

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Aus kinetischen Untersuchungen der Acetolyse der Titelverbindung (I), die zu den Produkten (II)‐(VI) führt, wird gefolgert, daß die anti‐Doppelbindung die Dissoziation nur geringfügig, wenn überhaupt, beschleunigt.

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