Disordered crystal structure of the potassium thiocyanate complex with 1,10-diaza-18-crown-6

The crystal structure of the potassium thiocyanate complex with 1,10-diaza- 18-crown-6, C12H26N2O4 . KSCN (I), was newly studied by X-ray diffraction a nalysis: space group P (1) over bar, a = 7.517, b = 8.040, c = 8.271 Angstr om, alpha = 101.84 degrees, beta = 91.29 degrees, gamma = 105.24 degrees, Z = 1. The disordered structure of I is refined by the full-matrix least-squ ares method in the anisotropic (isotropic for Il atoms) approximation for a ll 1978 unique reflections (CAD-4 automated diffractometer, lambda CuKalpha ); R = 0.064 for 1850 reflections with 1 greater than or equal to 2 sigma(l ). In structure I, the K+ cation is noticeably [by 0.190(2) Angstrom] offse t from the inversion center (center of the macrocycle) and is disordered ab out it. The SCN- anion is disordered about another inversion center. Owing to the disorder of the K+ cation, the crystal and molecular structures of I significantly differ from those reported in previous works.