Mixed-valence states of 11, 1111-dialkyl- and 11, 1111-bis(methylbenzyl)biferrocenium triiodides

It was found that the packing of cations and anions influences the electronic structures of mixed-valence binuclear ferrocene derivatives. Temperature-dependence of the mixed-valence state of 1¹, 1¹¹¹-diisobutylbiferrocenium triiodide was observed in a crystalline state, whereas only a trapped-valence state was found in a dispersed state. The packing effect was also observed for a series of 1¹, 1¹¹¹-dialkyl- and 1¹, 1¹¹¹-bis(methylbenzyl)biferrocenium triiodides by means of ESR spectroscopy.     

The norrish type II reaction of the cyclic thioimides with a benzylic hydrogen

On irradiation cyclic thioimides with N-ω-phenylalkyl substituents undergo the Norrish type II cyclization when benzylic hydrogen is available at the δ or ε-position of the thiocarbonyl group.     

Synthesis and evaluation of 3-methyl-4-oxo-6-phenyl-4,5,6,7-tetrahydrobenzofuran-2-carboxylic acid ethyl ester derivatives as potent antitumor agents

For the construction of new combinatorial libraries, a lead compound was created by replacing the core structure of a hit compound discovered by screening for cytotoxic agents against a tumorigenic cell line. The newly designed compound maintained biological activity and allowed alternative library construction for antitumor drugs.     

Rapid adsorption and entrapment of benzoic acid molecules onto mesoporous silica (FSM-16)

Changes in the molecular state of benzoic acid (BA) in the presence of folded sheet mesoporous material (FSM-16), which has uniformly sized cylindrical mesopores and a large surface area, were assessed with several analyses. When BA was blended with FSM-16 for 5 min (BA content=30%), the X-ray diffraction peaks of BA crystals disappeared, suggesting an amorphous state. Fluorescence analysis of the mixture showed a new fluorescence emission peak for BA at 386 nm after mixing with FSM-16. Fluorescence lifetime analysis of the BA component in the mixture at 386 nm showed a longer lifetime in comparison with that of BA crystals. The solid-state (13)C CP/MAS and PST/MAS NMR spectra of the mixture with FSM-16 showed a significantly different spectral pattern from the mixture with nonporous glass, whose NMR spectra were identical to those of BA crystals. These results indicate that BA molecules disperse quickly into the hexagonal channels of FSM-16 by a simple blending procedure and adsorbed BA molecules had clearly different physicochemical properties to BA crystals.     

A theory of the salt effects on the critical micelle concentration

Summary The previously proposed theory on the critical micelle concentration is extended and revised, considering the effects of coexisting small ions. Using the theory of the adsorption equilibrium instead of that of the flat electrical double layer, we obtain an equation for the salt effect on the c. m. c., which is of somewhat different form from the usual experimental formula. It is pointed out that the activities of ions should be used instead of the stoichiometric concentrations. Comparisons are made with available experimental works and the agreement is shown to be good.

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Zusammenfassung Die früher ver?ffentlichte Theorie (1) über die kritische Mizellkonzentration wurde erweitert und verbessert, indem wir die Wirkung der gleichzeitig anwesenden Ionen in Betracht zogen. Um den Effekt der Salze auf die kritische Mizellkonzentration zu untersuchen, benutzen wir die Theorie des Adsorptionsgleichgewichtes anstatt der Theorie der ebenen elektrischen Doppelschicht, und unsere Theorie führte zu einer von den üblichen experimentellen Formeln etwas verschiedenen Gleichung. Es wurde gezeigt, da? die Aktivit?t der Ionen anstatt der st?chiometrischen Konzentration gebraucht werden mu?. Unsere Theorie steht in guter übereinstimmung mit existierenden experimentellen Resultaten.

     

Solvation and dynamic behavior of cyclodextrins in dimethyl sulfoxide solution

High-frequency dielectric relaxation behavior up to 20 GHz was investigated for plain (alpha, beta, gamma) and (62 and 100%) methylated cyclodextrins, CDs, in dimethyl sulfoxide, DMSO, solution. Each hydrogen atom of OH groups of the CDs solvated a DMSO molecule for a residence time of 130-180 ps due to the hydrogen bond formation to an oxygen atom of DMSO, and a few DMSO molecules were included in cavities of the CDs for a while similar to the residence time. The overall rotational relaxation modes of solvated CDs were also observed depending on the effective sizes of the solvated CDs.