Pentazol‐Derivate und daraus entstehende Azide: [O3S—p‐C6H4—N5]— und [O3S—p‐C6H4—N3]— als Kalium‐Kronenether‐Salze |
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Authors: | Frank Biesemeier Klaus Harms Ulrich Müller |
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Abstract: | 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 KO3S—p‐C6H4—N5] and KO3S—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. |
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Keywords: | Pentazoles Azides Crown ether complexes Crystal structure Crystal packing |
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