Pentazol‐Derivate und daraus entstehende Azide: [O3S—p‐C6H4—N5]— und [O3S—p‐C6H4—N3]— als Kalium‐Kronenether‐Salze

Pentazole Derivates and Azides Formed from them: Potassium‐Crown‐Ether Salts of [O₃S—p‐C₆H₄—N₅]^— and [O₃S—p‐C₆H₄—N₃]^{— —}O₃S—p‐C₆H₄—N₂⁺ was reacted with sodium azide at —50 °C in methanol, yielding a mixture of 4‐pentazolylbenzenesulfonate and 4‐azidobenzenesulfonate (amount‐of‐substance ratio 27:73 according to NMR). By addition of KOH in methanol at —50 °C a mixture of the potassium salts K[O₃S—p‐C₆H₄—N₅] and K[O₃S—p‐C₆H₄—N₃] was precipitated (ratio 60:40). A solution of this mixture along with 18‐crown‐6 in tetrahydrofurane yielded the crystalline pentazole derivate [THF‐K‐18‐crown‐6][O₃S—p‐C₆H₄—N₅]·THF by addition of petrol ether at —70 °C. From the same solution upon evaporation and redissolution in THF/petrol ether the crystalline azide [THF‐K‐18‐crown‐6][O₃S—p‐C₆H₄—N₃]·THF was obtained. A solution of the latter in chloroform/toluene under air yielded [K‐18‐crown‐6][O₃S—p‐C₆H₄—N₃]·1/3H₂O. According to their X‐ray crystal structure determinations [THF‐K‐18‐crown‐6][O₃S—p‐C₆H₄—N₅]·THF and [THF‐K‐18‐crown‐6][O₃S—p‐C₆H₄—N₃]·THF have the same kind of crystal packing. Differences worth mentioning exist only for the atomic positions of the pentazole ring as compared to the azido group and for one THF molecule which is coordinated to the potassium ion; different orientations of the THF molecule take account for the different space requirements of the N₅ and the N₃ group. In [K‐18‐crown‐6][O₃S—p‐C₆H₄—N₃]·1/3H₂O there exists one unit consisting of one [K‐18‐crown‐6]⁺ and one [O₃S‐C₆H₄—N₃]^— ion and another unit consisting of two [O₃S‐C₆H₄—N₃]^— ions joined via two [K‐18‐crown‐6]⁺ ions and one water molecule. The rate constants for the decomposition [O₃S‐C₆H₄—N₅]^— → [O₃S‐C₆H₄—N₃]^— + N₂ in methanol were determined at 0 °C and —20 °C.