Stereochemistry,tautomerism, and reactions of acridinyl thiosemicarbazides in the synthesis of 1,3‐thiazolidines

Acridin‐9‐yl hydrazine upon treatment with various isothiocyanates (RNCS, R = methyl, allyl, phenyl, p‐methoxy phenyl, and p‐nitro phenyl) yielded the corresponding thiosemicarbazides with acridine substituted on the carbazide‐type side. The alkyl‐substituted compounds were present in solution as equilibria consisting of the major H‐10, H‐12 tautomer (either E or Z or both about the C₁₃‐N₁₄ bond) and the minor H‐10, SH tautomer (either E or Z or both). The major species for the aromatic‐substituted compounds was the H‐10, H‐12 E tautomer, with the evident minor species being the H‐10, H‐12 Z tautomer. The thiosemicarbazides were each quantitatively converted into the analogous semicarbazides upon treatment with mesitylnitrile oxide wherein all structures were present in solution as the H‐10 tautomers with Z conformation about the C₁₃‐N₁₄ bond. Methylation of the compounds with methyl iodide yielded S‐methylated compounds wherein the Z configuration dominated in each case over the E configuration along the N₁₂‐C₁₃ double bond. Treatment of the thiosemicarbazides with methyl bromoacetate resulted in the formation of 1′,3′‐thiazolidin‐4′‐ones wherein the Z configuration predominated in each case over the E configuration along the N₁₂? C₁₃ double bond. With bromoacetonitrile as the bifunctional electrophile, the initial 1′,3′‐thiazolidin‐4′‐imines that formed spontaneously underwent Dimroth‐type rearrangement to the regiosiomeric 1′,3′‐thiazolidin‐4′‐imines.     

Cu–Ni hetero-bimetallic compounds,Part 1: Preparation,structure and properties of [Cu0.05Ni0.95(bpy)2(ox)]·4H2O

New bimetallic compound [Cu_xNi_1?x(bpy)₂(ox)]·4H₂O (x = 0.05, ox = oxalato, bpy = 2,2′-bipyridine) was synthesized and chemically characterized. Its crystal structure is molecular. The octahedron around the metal central atom is deformed due to coordination by one bidentate oxalate anion and two bpy ligands. There are four uncoordinated water molecules in the asymmetric unit. The metal site is occupied by both Cu(II) and Ni(II) atoms in the 5:95 ratio. The complex molecules interact with water molecules through hydrogen bonds and, moreover, π–π interactions between aromatic rings lead to a 1D arrangement of molecules. The susceptibility data measured down to 2 K were analyzed using strong-coupling theory and the best agreement with the experimental data were found for g = 2.1, D/k = 5.6, E/k = 0.35, J/k = 0.2. The dehydration starts at 30 °C. As a final product of its thermal decomposition a solid solution of Cu_xNi_1?xO was detected by X-ray powder diffraction.     

X‐Treme beamline at SLS: X‐ray magnetic circular and linear dichroism at high field and low temperature

X‐Treme is a soft X‐ray beamline recently built in the Swiss Light Source at the Paul Scherrer Institut in collaboration with École Polytechnique Fédérale de Lausanne. The beamline is dedicated to polarization‐dependent X‐ray absorption spectroscopy at high magnetic fields and low temperature. The source is an elliptically polarizing undulator. The end‐station has a superconducting 7 T–2 T vector magnet, with sample temperature down to 2 K and is equipped with an in situ sample preparation system for surface science. The beamline commissioning measurements, which show a resolving power of 8000 and a maximum flux at the sample of 4.7 × 10¹² photons s^?1, are presented. Scientific examples showing X‐ray magnetic circular and X‐ray magnetic linear dichroism measurements are also presented.     

Tetracyanometallates with Complex Dien Cations: [Ni(dien)2][Ni(CN)4]·2H2O and [Ni(dien)2][Pd(CN)4]

The crystal structures of two square tetracyanocomplexes were determined. [Ni(dien)₂][Ni(CN)₄]·2H₂O (NDNCH) and [Ni‐(dien)₂][Pd(CN)₄] (NDPC) (dien = diethylene triamine) exhibit ionic structures consisting of mer‐[Ni(dien)₂]²⁺ cations and [Ni(CN)₄]^2‐ or [Pd(CN)₄]^2‐ anions, respectively. Moreover, the structure of NDNCH is completed by two water molecules of crystallisation. In both compounds hydrogen bonds contribute to the stabilisation of the structure. NDNCH dehydrates on air quickly yielding anhydrous [Ni(dien)₂][Ni(CN)₄] (NDNC). Its thermal decomposition proceeds in a complicated process followed by aerial oxidation of metallic nickel to NiO.     

New materials with high π conjugation by reaction of 2-oxazoline containing phenols with polyamidines and inorganic base

The non-covalent interactions between 2-oxazoline containing phenols and an aliphatic polyamidines as well as an inorganic base were studied. The reaction of a weak acid with a strong base results in the formation of the deprotonated species and subsequently in the formation of a new electronic structure. A bathochromic shift of the wavelength of the absorption maxima of the chromophores bounded to polyamidine was observed. Depending on the structure of the chromophore, the shift of the absorption maxima is 40-100 nm. The changes in photochemical behavior can be explained by the higher portion of quinoid structures in the conjugated π-system. The degree of deprotonation is dependent on the molar ratio of the chromophore and the polymeric base. Analogous results were obtained with an inorganic base.     

Properties of polystyrene/poly(butyl acrylate) core/shell polymers modified with N‐methylol acrylamide

Polystyrene/poly(butyl acrylate) PS/PBA polymer dispersions with core/shell particles functionalized by N‐methylol acrylamide (N‐MA) were prepared through two‐step emulsion polymerization. The influence of N‐MA situated in shell and/or in core/shell of particles on the crosslinking reaction was studied to relate its mechanical properties and organic solvent resistance of films cast from basic and modified PS/PBA latexes. The changes in the phase arrangement of functionalized and unfunctionalized films after treatment with solvent and annealing were monitored. It was found that at the presence of N‐MA the crosslinking reaction occured already during the polymerization. Films from functionalized dispersions exhibit improved tensile strength and higher resistance against organic solvent.     

Azo‐group labelled polyesters by end‐capping with 2‐oxazoline derivatives – preparation

Two azobenzene containing 2‐oxazolines were used for labelling of polyesters with carboxylic end groups by the end‐capping method. The reaction proceeded under the conditions of reactive processing, and in a solution. High conversions in melt were achieved in several minutes. The coupling of the modifiers was proved by NMR spectroscopy.