Novel 2-benzothiazole-, 4-pyridine-, and 2- and 4-quinoline-based styryl dyes containing an N-methylbenzoaza-15(18)-crown-5(6)-ether moiety were synthesized. A detailed electronic spectroscopy study revealed high performance of these compounds as optical molecular sensors for alkali and alkaline-earth metal cations. They were shown to considerably surpass analogous chromoionophores based on N-p...

INTRODUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ......... 582 ALKALI-CATION SELECTIVITY IN NONLIVING SySTEMS..... . . . . . . . . . . . . . . .. 583 ALKALI-CATION SELECTIVITY IN BIOLOGICAL SYSTEMS. . . . . . . . . . . . . . . . . . .. 587 THE ORIGIN OF ALKALI-CATION EQUILIBRIUM SELECTIVITY .. .. . .. . .... . " 589 ANION SELECTIVITY. . . • . . . . . ....

A series of adamantane functionalized diaza-lariat ethers 1–6 have been prepared and alkali metal picrate extraction profiles determined. The ability of aza-crown ethers 1–6 to extract the alkali metal picrates was compared with that of diaza-18-crown-6 (7) and N,N '-dibenzodiaza-18-crown-6 (8). Na and K transport across bulk liquid membrane was also measured. The results of alkali metal cation...

Human cytochrome P450 46A1 (CYP46A1) is one of the key enzymes in cholesterol homeostasis in the brain. The crystallization and heavy-atom structure solution of an active truncated CYP46A1 in complex with the high-affinity substrate analogue cholesterol-3-sulfate (CH-3S) is reported. The 2.6 angstroms structure of CYP46A1-CH-3S was solved using both anion and cation heavy-atom salts. In additio...

A new working principle for detecting inorganic cation binding by water-soluble calix[4]arenes involves the displacement of a fluorescent azoalkane as guest. Fluorescence regeneration is observed for various metal ions, and binding of monovalent cations (alkali and ammonium) to p-sulfonatocalix[4]arene is detected and quantified for the first time.

The potential range of the transition region between the diffusion-limited reduction to oxidation of hydrogen peroxide depends strongly on the nature of the cation of the supporting alkaline electrolyte. Non-covalent interactions between the hydrated alkali metal cations and chemisorbed OH species on platinum influence the potential-dependent reaction kinetics.

We report a multinuclear solid-state ( (23)Na, (39)K, (87)Rb, (133)Cs) NMR study of tetraphenylborate salts, M[BPh 4] (M = Na, K, Rb, Cs). These compounds are isostructural in the solid state with the alkali metal ion surrounded by four phenyl groups resulting in strong cation-pi interactions. From analyses of solid-state NMR spectra obtained under stationary and magic-angle spinning (MAS) cond...

The syntheses of two di(1,8-naphtho)-16-crown-4 compounds are described. In the X-ray structure of di(1,8-naphtho)-16-crown-4, the compound crystallizes in the orthorhombic space group Pna21 with four molecules per asymmetric unit. Alkali metal cation selectivities of the ionophores are assessed in solvent polymeric membrane electrodes.

A modified graphene oxide containing aza-9-crown-3 ether units covalently anchored has been prepared; aqueous suspensions of this material in the presence of Li(+), Na(+) and K(+) cations exhibit enhanced electrochemical response, enhanced photoinduced charge separation and longer lifetimes, facts that can be attributed to stabilization of electrons on graphene oxide by the nearby alkali metal ...