The interaction of uranyl ion with acetic, glycolic, malic, tartaric, tricarballylic, and citric acids in aqueous solution has been investigated by means of IR and 13C NMR spectroscopy. The complex formation is reflected in the IR frequency shifts for the COO-stretching vibrations (yM(COO) and vs(COO)) and the asymmetric 0=U=0 stretching mode 03). The possible coordination structures of COO groups to the uranyl ion in the individual systems are discussed in terms of the IR frequencies of the vas(COO) and ys(COO) modes. The model calculation of the nas(COO) and vs(COO) frequencies based on a normal-coordinate treatment has indicated that the carboxylate coordination in the uranyl acetate and tricarballylate complexes is assigned to a bidentate structure in which both the two oxygen atoms in a given COO group take part in the coordination and that in the uranyl glycolate, lactate, malate, tartrate, and citrate complexes only one of the two oxygen atoms in a given carboxylate of the individual ligands coordinates to the uranyl ion. The carboxylate 13C NMR signals for all the systems examined have experienced significant shifts going from the individual free ligands to the complex species, which suggests the coordination of the carboxylate groups to the uranyl ion. Consideration of the alcoholic 13C NMR signals of the uranyl complexes involving glycolate, lactate, malate, tartrate, and citrate has indicated that the uranyl ion interacts with the alcoholic oxygen as well as the carboxylate oxygen of the individual ligands. The presence of some uranyl complex species, in which the alcoholic oxygen in a given -COH group coordinates to uranyl ion with dissociation of protons, was revealed by the observation of an unusually large lower magnetic field shift of the alcoholic carbon signal. The possible structures of the main uranyl complex species present in aqueous solution, compatible with the IR and 13C NMR evidence, are proposed and discussed.

The infrared spectra of CH3CH2COONa and its 13C-labeled modifications (1-13C, 2-13C, and 3-13C) suspended in KBr disks were measured in the region 4000 -200 cm-1 at room temperature and liquid nitrogen temperature. Overlapping complex band contours appeared in some regions of the room temperature spectrum, most notably in the region 1500 -1350 cm-1, where 5 fundamentals having contributions from the methyl deformation, methylene bending, and carboxylate stretching modes should occur. In contrast to this, excellent resolution was reached at the low temperature, from which all 22 fundamentals expected in the whole spectral region investigated were detected. A complete assignment of the fundamentals is proposed mainly on the basis of the characteristic isotopic shifts of the three 13C substituted sodium propionate species. A fair number of the fundamentals were found to feature coupled modes having contributions from several group vibrations.

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The infrared spectra (4000-100 cm " 1) of the a-form crystal of glycine (NH 3 -CH, -COO ") and of thirteen isotopic modifications comprising D, 13C, 1SN, and O were measured at 80 and 290 K. Excellent resolution was reached at the low temperature. In the low temperature spectra the fine structure of the nearly degenerate NH3 and ND3 antisymmetric deformational modes and the C02-torsional bands in the vicinity of 200 cm-1 for each of the isotopic molecules, which in the low-frequency region are strongly overlapped by a number of lattice modes, clearly showed up. Based upon the frequency data of the 14 isotopic analogs and the precisely known structure of the molecule, a normal coordinate analysis was carried out. 307 observed frequencies were utilized to derive a new empirical valence force field reduced to a set of 50 force constants by a number of restrictive assumptions. The resulting force field reproduced the 307 frequencies with a root-meansquare deviation of 3.32 cm-1. This force field emphasizes the importance of interaction force constants of the in-plane C 02-rocking and C 02-deformational coordinates with the CH2-twisting coordinate, which can come form a significant deviation of this molecule from an ideal Cs-symmetry. The composition of normal vibrations from generally accepted local-symmetry coordinates is given in terms of the potential energy distribution (PED). The PED results indicate that almost all the normal modes below 1600 cm' 1 are extensively intermixed group modes, thus precluding a simple normal vibrational decription. Interestingly the PED description for several vibrations associated with the NHj -CH2 -C fragment exhibits strong mixing between quasi-,4' symmetric and -A" antisymmetric coordinates with respect to a pseudo molecular symmetry (CCN) plane in this molecule.

Separation of rubidium isotopes (