Mechanistic studies on the aliphatic ligand hydroxylation in a copper complex of tridentate ligand 1a {N,N-bis[2-(2-pyridyl)ethyl]-2-phenylethylamine} by O2 have been performed in order to shed light on the structure and reactivity of the active oxygen species of our functional model for copper monooxygenases (Itoh, S.; et al. J. Am. Chem. Soc. 1995, 117, 4714). When the copper complex [CuII(1a)(ClO4)2] was treated with an equimolar amount of benzoin and triethylamine in CH2Cl2 under O2 atmosphere, efficient hydroxylation occurred selectively at the benzylic position of the ligand to provide oxygenated product 2a {N,N-bis[2-(2-pyridyl)ethyl]-2-phenyl-2-hydroxyethylamine} quantitatively. An isotope labeling experiment using 18O2 confirms that the oxygen atom of the OH group in 2a originates from molecular oxygen. Spectroscopic analyses using UV−vis, resonance Raman, and ESR on the reaction of [CuI(1a)]+ and O2 at low temperature show that a μ-η2:η2-peroxodicopper(II) complex is an initially formed intermediate. Kinetic analysis on the peroxo complex formation indicates that the reaction of the Cu(I) complex and the monomeric superoxocopper(II) species is rate-determining for the formation of the μ-η2:η2-peroxodicopper(II) intermediate. When ligand 1a is replaced by 1,1,2,2-tetradeuterated phenethylamine derivative 1a- d 4, a relatively small kinetic deuterium isotope effect (k H/k D = 1.8 at −40 °C) is observed for the ligand hydroxylation step. The rate of the hydroxylation step is rather insensitive to the p-substituent of the ligand [(PyCH2CH2)2NCH2CH2Ar, 1a Ar = C6H5; 1b Ar = p-CH3C6H4, 1c Ar = p-ClC6H4, and 1d Ar = p-NO2C6H4)], but it varies depending on the solvent (THF > acetone > CH3OH > CH2Cl2). The p-substituent, the solvent, and the kinetic deuterium isotope effects suggest that O−O bond homolysis of the μ-η2:η2-peroxodicopper(II) intermediate is involved as a rate-determining step in the aliphatic ligand hydroxylation process. Based on the results of the kinetics and the crossover experiments, we propose a mechanism involving intramolecular C−H bond activation in a bis-μ-oxodicopper(III) type intermediate for the ligand hydroxylation reaction.

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LysPE40 is a modified form of Pseudomonas exotoxin that lacks the cell-binding domain and has a chemically reactive lysine residue near the amino terminus. LysPE40 is made in Escherichia coli and secreted into the medium from which it is readily purified. Two immunotoxins were constructed by coupling LysPE40 to an antibody to the human transferrin receptor (TFR) or to an antibody to the human interleukin-2 receptor. These immunotoxins were selectively cytotoxic to receptor-bearing cells in tissue culture. Anti-TFR-LysPE40 given intraperitoneally to mice appeared rapidly in the blood and caused regression of A431 tumors growing as subcutaneous xenografts. These results show that it is possible to cause regression of a solid carcinoma by an immunotoxin if proper targeting can be achieved.

Liquid ZrO 2 is one of the most important materials involved in severe accident analysis of a light-water reactor. Despite its importance, the physical properties of liquid ZrO 2 are scarcely reported. In particular, there are no experimental reports on the viscosity of liquid ZrO 2 . This is mainly due to the technical difficulties involved in the measurement of thermo-physical properties of liquid ZrO 2 , which has an extremely high melting point. To address this problem, an aerodynamic levitation technique was used in this study. The density of liquid ZrO 2 was calculated from its mass and volume, estimated based on the recorded image of the sample. The viscosity was measured by a droplet oscillation technique. The density and viscosity of liquid ZrO 2 at temperatures ranging from 2753 K to 3273 K, and 3170 K–3471 K, respectively, were successfully evaluated. The density of liquid ZrO 2 was found to be 4.7 g/cm 3 at its melting point of 2988 K and decreased linearly with increasing temperature, and the viscosity of liquid ZrO 2 was 13 mPa at its melting point.