INFRARED SPECTRAL INVESTIGATION OF SOME COMPLEXES OF URANYL AND THORIUM SALTS WITH CROWN ETHERS

The infrared spectrometrec analysis of the 18-crown-6, benzo-15-crown-5 and dibenzo-18-crown-6, as well as their complexes with nitrate provide evidence that it is impossible to record real infrared spectra with KBr-pressed-disk technique, but it can be obtained by Nujol Mull technique. As crown ethers are converted to complexes with metal salts, shift of the characteristic frequencies in IR-spectrometry of the complex compounds might be observed. The fact that the IR spectra for complexes of 18CR6 with metal salts was simpler in comparison with the free 18CR6 and was similar to one another, as observed by R.M. Costes et al. in KBr pellets, is thus explained. Moreover, the reason for the occurence of the absorption peak at 1380cm-1 with the crown ether complexs of metal nitrates embedded in KBr pellets is also described. Our view differs from that in the literature on ascribing the absorption peak in the 1500-1560 cm-1 region of the IR spectra of the crown ether complexes with metal nitrates, and we think these strong absorptions should be ascribed to the absorption of NO3- in the complexes instead of absorption resulting from a large displacement of the scissoring vibration of CH2 of crown ethers.