The 1 : 1 complexes of lanthanide(III) ions such as La(III), Pr(III), Nd(III), Gd(III) and Er(III) with tris-(salicylidene amino)-triethylenetetramine have been prepared. Among these complexes, the lanthanum(III) complex is unique in infrared spectra and solubility to the solvents; it is soluble in chloroform and nitrobenzene and found to be dimeric in chloroform solution. The other lanthanide(III) complexes are practically insoluble in any available solvents, and are assumed to be polymeric.

The reduction mechanism of bis 2,2′,2″-terpyridine complexes of manganese(II), cobalt(II), nickel(II) and europium (III) were investigated in acetonitrile by means of DC and AC polarograph and Kalousek polarograph at DME and cyclic voltammetry at an HDME. It was found that univalent metal complex anions, such as [M-(terpy)2]− (M=manganese and nickel), were formed at the electrode surface in acetonitrile. For the europium(III) complex, the standard rate constant of the second reduction step was estimated.

Copper(II) complexes with some natural amino acids were prepared, and their powder ESR spectra were measured. The pattern types of the ESR spectra of these Cu(II) complexes with amino acids were classified into four types, and by the pattern type, the cis- or trans-isomer was estimated.

The infrared spectra of tris-(acetylacetonato) complexes of praseodymium(III), neodymium-(III), europium(III), gadolinium (III), dysprosium(III), and erbium(III) have been measured in the range between 4000 and 100 cm-1 in order to obtain information about the nature of lanthanide metal-oxygen bond; some properties of these complexes were studied, also. The calculated frequencies and assignments were used to elucidate the complex spectra and to show the relations between the calculated force constants and some physicochemical properties. Although the molecules of each complex were 1 : 3 complexes, the calculation of the vibrational frequencies was made by using a simplified model of the 1 : 1 complex (C2v), because it may be supposed that this tris-(acetylacetonato) complex does not always have a regular octahedral symmetry in spite of the composition of Ln(acac)3. The calculated frequencies were in good agreement with the observed ones; the lanthanide metal-oxygen stretching vibrations were found at 420-432 cm-1 (A1-v5) and 304-322 cm -1 (B1-v14). The lanthanide metal-oxygen stretching force constant increases with an increase in the atomic number, while the corresponding C=O stretching frequency (A1-v1) decreases in the same order. For example, the values of K(Pr-O) and K(Er-O) are 2.10 and 2.29 and/A respectively. As the result of the lanthanide contraction, the force constant of the lanthanide metal-oxygen bond increases with a decrease in the M-O The preparations and infrared spectra of acetylacetonate complexes of various metal ions,1-13) especially of the first transition metal ions, have been studied by many investigators.In this paper, some systematic studies of tris-(acetylacetonato) lanthanide(III) complexes, Ln(acac)3, that is, their preparations, the measurements of the infrared spectra in the 4000-100 cm-1 region, the calculation of the stretching force constants of the metal-oxygen bonds of these complexes, and some physico-chemical properties, will be presented. Furthermore, the relations of the overall stability constants, the electronegativities of lanthanide metal ions, and the M-O bond distances to the band shifts and the force constants of metaloxygen bonds will be discussed.

When Luteo salt was added to beryllium carbonate complex solution, the precipitate [Co(NH3)6] [(H2O)2Be2(CO3)2(OH)3]·3H2O was obtained. In this experiment, the indirect determination of beryllium was tried by the titration of the cobalt content in the precipitate with EDTA. The following procedures were examined mainly; the formation of the precipitate II, the decomposition of the precipitate and titration of cobalt in the presence of beryllium. In the optimum conditions, 0.70 to 3.50 mg. of beryllium were determined quantitatively. This method could be applied to separation and determination of beryllium from iron(III), aluminum and magnesium by using EDTA as a masking agent.