Zur Struktur von (Pyrazolinonyl)-(hydroxypyrazolylium)methanperchloraten NMR-, IR-spektroskopische Studien und Kristallstruktur / The Structure of (Pyrazohnonyl)-(hydroxypyrazolyhum)methaneperchlorates NMR, IR Spectroscopic Studies and Crystal Structure

The structures of 1a-1d were investigated by spectroscopic methods and in the case of la in addition by X-ray diffraction, 1a, vicarious for the compounds 1, is stabilized in solution and in the crystal by an intramolecular hydrogen bond in an eight-membered ring. The IR and NMR spectra show that 1 exhibit a symmetrical structure. In the case of 1 a the molecular structure is affected by unsymmetrical packing and electrostatic effects in the crystal and is therefore approximated best between the forms I and II.