A Potassium Complex of a Fluorine-Containing Macrocyclic Cage Compound: Interactions between Fluorine Atoms and Metal Ions

A new donor , the C−F unit, can be added to the field of host–guest chemistry. The interaction between fluorine atoms and a potassium ion was proven with the fluorine-containing cage compound 1 as a host. The six fluorine atoms of K⁺⊂ 1 are coordinated to K⁺ in a distorted octahedral fashion.     

Recent advances in the synthesis of N-alkenyl carbazoles

N-Alkenyl carbazoles are important building blocks of poly(vinylcarbazole), which is used in photosensitive materials, semiconductors, electroluminescent devices, and non-linear optical materials. Recently, a CN bond formation reaction using transition-metal-catalyzed amination and transition-metal-catalyzed vinylation was successfully extended to the synthesis of N-alkenyl carbazoles. In this paper, I discuss recent examples of the synthesis of N-alkenyl carbazoles, including palladium and copper-catalyzed cross-coupling reactions of carbazoles with alkenes/alkenyl halides, and iridium-catalyzed vinylation of carbazole using vinyl acetate.     

One-dimensional Kalman filter in a robot system for total analysis of solid dosage formulations

A one-dimensional Kalman filter for peak resolution is applied to a totally automated robot system for liquid chromatographic analysis of solid dosage formulations. Sample solutions were prepared from four tablets of clemastine fumarate (1 mg/tablet) and injected automatically at regular, short intervals onto the column by the robot system. The overlapped peaks in the resulting complicated chromatogram were resolved and evaluated quantitatively by the one-dimensional filter. The peak-resolving powers are shown to be reliable by comparison with a multidimensional Kalman filter. The applicability of the whole analytical system with the linear Kalman filter is discussed.     

Nickel-catalyzed carboxylation of aryl and vinyl chlorides employing carbon dioxide

Nickel-catalyzed carboxylation of aryl and vinyl chlorides employing carbon dioxide has been developed. The reactions proceeded under a CO(2) pressure of 1 atm at room temperature in the presence of nickel catalysts and Mn powder as a reducing agent. Various aryl chlorides could be converted to the corresponding carboxylic acid in good to high yields. Furthermore, vinyl chlorides were successfully carboxylated with CO(2). Mechanistic study suggests that Ni(I) species is involved in the catalytic cycle.     

Visualization of transient interfacial waves induced by spin-up of two immiscible fluid layers

Abstract  

Interfacial waves of two immiscible layers in a spin-up container were investigated using experimental visualization. While the interface near the central part rose up, instability waves propagated in an azimuthal direction on the interface. These waves were mainly caused by Kelvin–Helmholtz instability for the velocity difference between two layers during spin-up, but had complicated transient characteristics owing to the rotation in a closed system. We visualized the structure of the interfacial waves by the use of three types of optical characteristics of the interface. Image processing provided the detailed factors of the interfacial waves that were classified in four life stages from their generation to disappearance. The initial generation process involved many frequency modes due to a large velocity difference, and then a low mode stood out during the growth, and disappeared with an ellipsoidal sloshing mode to achieve the rigid rotation in both layers.     

A Redox-Active Microporous Organosiloxane Containing a Stable Neutral Radical,Trioxotriangulene

A new silyl-substituted trioxotriangulene ( TOT ) neutral radical and corresponding porous organosiloxanes (POSs) were synthesized. The neutral radical exhibited a peculiarly high stability and formed a diamagnetic π-dimer characteristic to TOT neutral radicals stabilized by the strong multiple SOMO-SOMO interaction in both solution and solid states. POSs including TOT units within the organosiloxane-wall were prepared by polycondensation of the silyl groups and formed microporous structures with ∼1 nm-size diameters. Redox ability of TOT units in the POS was demonstrated by the treatment of oxidant/reductant in heterogeneous suspension condition, where the TOT units were reversibly converted between reduced and neutral radical species. Furthermore, the solid-state electrochemical measurements of the POS revealed the reversible multi-stage redox ability of TOT units involving polyanionic species within the organosiloxane-wall.