Development in Synthesis,Electrochemistry, LB Moieties of Phenothiazine Based Units

A convenient and higher yielding synthetic route to N‐alkyl‐bis(thiophene)phenothiazine derivatives is reported and their aggregation, electrochemical properties and polymerization are characterized. The key step in the synthesis of this group of compounds has been the Stille type coupling reaction between the N‐alkyldibromophenothiazine and tin derivatives of thiophene as the best way for preparation of conjugated N‐alkylphenothiazine derivatives. For this group of compounds we also present an electrochemical polymerization effect and widely adopted approach to prepare structurally ordered thin, electroconducting films by Langmuir–Blodgett technique.     

Imaging of tautomerism in a single molecule

Fluorescence imaging is used to visualize directly the transfer of two inner hydrogen atoms in single porphycene molecules. This reaction leads to a chemically equivalent but differently oriented structure and hence results in a rotation of the transition dipole moments. By probing single immobilized molecules with an azimuthally polarized laser beam in the focal spot of a confocal microscope we observe ring-like emission patterns, possible only for a chromophore with two nearly orthogonal transition dipole moments. Numerical simulations of the observed emission patterns yield a value of 72 degrees for the angle between the S0-S1 transition moments in the two tautomeric forms.     

Tetra­kis(1‐eth­yl‐1H‐1,2,4‐triazole‐κN4)bis­(nitrato‐κO)copper(II) and bis­(nitrato‐κO)tetra­kis­(1‐prop­yl‐1H‐1,2,4‐triazole‐κN4)copper(II)

The copper(II) environments for tetra­kis­(1‐eth­yl‐1,2,4‐triaz­ole)­dinitratocopper(II), [Cu(NO₃)₂(C₄H₇N₃)₄], and tetrakis­(1‐prop­yl‐1,2,4‐triazole)dinitratocopper(II), [Cu(NO₃)₂(C₅H₉N₃)₄], are distorted square bipyramidal. Both structures are centrosymmetric, with the copper(II) ions located at inversion centers coordinated by four N atoms of four triazole mol­ecules and by two O atoms of two nitrate ions in an elongated octa­hedral geometry. This elongation is a result of the Jahn–Teller effect. The largest distortion is that of the N—Cu—O angles, which differ from 90° by 5.68 (10)° in the eth­yl and 5.59 (8)° in the prop­yl derivative.     

Effect of crown-ether surfactants on flame atomic absorption and flame emission signals of some monovalent cations

Two surface-active and one surface-inactive 18-crown-6 derivatives were synthesized and evaluated for their abilities to enhance flame atomic absorption and flame emission signals of monovalent cations. Enhancement of potassium signals were noted for the surface-active compounds but not for the surface-inactive compound. The critical micelle concentration was determined and compared to the degree of enhancement. Surfactant-induced signal enhancements are not due to the slight or moderate decrease in the size of the aerosol first produced in the nebulizing chamber. Additional mechanistic considerations are discussed.     

Stoffwechselprodukte von Mikroorganismen. 237. Mitteilung. (2S, 3R, 4R, 6R)-2,3,4-Trihydroxy-6-methylcyclohexanon aus zwei Actinomyceten-Stämmen

(2S, 3R, 4R, 6R)-2,3,4-Trihydroxy-6-methylcyclohexanone from Two Strains of Actinomycetes A tetrazolium-blue positive compound was isolated from two strains of acinomycetes. Its constitution and relative configuration 1 were determined by spectroscopic methods, and the absolute configuration by degradation to (+)-(R)-methylsuccinic acid.