Satoshi Kusakabe

Multiple-wavelength data treatment of ultraviolet—visible spectra for 1:1 electron donor—acceptor adducts of p-nitrophenol in heptane

Abstract The absorbances of solutions of p-nitrophenol and an electron donor in heptane are measured at 298 K over 240–400 nm at 1-nm intervals. The data are treated by a personal computer; on each spectrum, the differences between the measured absorbance and the absorbance calculated from an assumed formation constant are accumulated over the whole wavelength region, and divided by a normalizing factor which is obtained from the area under the measured spectrum. The optimal values of the constant for each spectrum are then averaged. The 1:1 adduct formation constants, log Kas, were 2.22 ± 0.17 for 4-methyl-2-pentanone, 3.95 ± 0.06 for N,N-dimethylacetamide, and 5.55 ± 0.13 for trioctylphosphine oxide. The method is applicable for various systems with this kind of equilibrium and has advantages over least-squares procedures.

Relationship Between Lewis Acidity of Organic Solvents and Europium(III) Extraction in a Synergistic System

Abstract To discuss the difference in magnitude of the synergistic effect among organic solvents, the extraction of europium(III) with pivaloyltrifluoroacetone and/or 1,10‐phenanthroline (phen) into chloroform (CHCl3), bromoform (CHBr3), pentachloroethane (C2HCl5), 1,1,2,2‐tetrachloroethane (C2H2Cl4), trichloroethylene (C2HCl3), and dichloromethane (CH2Cl2) has been measured. Further, the solubility of water in the organic solvents, the hydration number of the extracted species, and the interaction between the solvents and phen have been examined by Karl Fischer coulometric titration, by the luminescence lifetime of europium(III), and by IR spectra, successively. The effect of the Lewis acidity of organic solvents on the extractability of Eu ion has been explained in terms of the interaction between the Lewis bases and the organic solvents as well as the hydration of the chelates and water content in the organic solvents.