Thermal properties of complexes of amaranthus starch with selected metal salts

Metal cations (Cu(II), Fe(III), Mn(II), and Ni(II)) are ligated by amaranthus starch as proven by EPR spectra and conductivity measurements. The hydroxyl groups of starch are the coordination sites. The acetate and nitrate anions of the metal salts behave as bidentate ligands and reside in the inner coordination sphere of resulting polycenter Werner complexes. There is only a weak degeneration of orbitals of central metal ions caused by a shift of unpaired spin from the central atom to the ligand. The ligation of the central metal atoms resulted in a variation of the thermal stability, pathway, and rate of thermal decomposition of starch as proven by thermogravimetric (TG) and differential scanning calorimetric (DSC) measurements.     

Emissive Properties and Intramolecular Charge Transfer of Pyrazoloquinoline Derivatives

The fluorescence properties of several pyrazoloquinoline derivatives were performed by stationary as well as by time-resolved spectrosopy. Non-donor-substituted compounds show a high quantum yield; transition dipole moments of absorption and fluorescence as well as experimental and calculated lifetimes are in excellent agreement. The donor-substituted compound DMA-DPPQ exhibits a charge transfer fluorescence in polar solvents. Additionally, dual fluorescence appears in polar protic solvents. The nature of the charge transfer state is discussed with respect to the the TICT model.     

Xanthan gum-gelatin complexes

Gelatin (G) and xanthan gum (X) formed complexes either on bringing their blends to pH 2.3 or carrying out the electrode process in aqueous blends of X and G at pHs from 9 to 11. X carboxylic groups and G peptide moieties were involved in the interactions between the partners. Also non-coulombic interactions with involvement of NH and OH groups, as well as hydrophobic interactions were involved, as proved by FTIR and thermal analyses, respectively. The reaction yield declined with increase of concentration of G in the blends. Simultaneously, the thermal stability of the complexes slightly increased with increase in G content in the blend. The latter increased with its concentration in the reaction mixture. Slow formation by electrosynthesis provided more an organised matrix.     

The Polarized Light-Induced Enzymatic Formation and Degradation of Biopolymers

Summary: White, linearly polarized transformed starch amylopectin into amylose. Moreover, it activated α-amylolysis of starch, hydrolysis of xylane with xylanase, hydrolyses of chitin with chitinase, chitosan with chitosanase, and, interestingly, influenced production of cyclodextrins with cyclodextrin glycosyltransferase. Effect of duration of illumination of cyclodextrin glucosyltransferase with polarized light had certain effect upon the yield and isomer ration of three isomeric cyclodextrins. Application of the polarized light required 1–2 hour illumination of the enzymes in a small reaction vessel followed by admixture of so activated enzymes to a bioreactor. Further reactions did not require any illumination.     

The direct acylamination of pyridine 1-oxides. Effect of substituents in N-phenylarylimidoyl chloride. Trapping with thiols

The effect of a para-substituent in the benzoic acid portion of the arylimidoyl chloride on the nature and yield of products in the reaction with pyridine 1-oxide has been studied. When an electron-withdrawing substituent is present no acylamination product is formed and only 2- and 3-chloropyridine are isolated. When benzenethiol is added a respectable yield of 3-phenylthiopyridine is obtained, but alkanethiols gave low yields of 3-alkylthiopyridines.     

Oxidation of pyridines with copper sulfate

Oxidation of pyridine, 3-picoline, 3,5-lutidine, quinoline, isoquinoline and acridine with hydrated copper sulfate at high temperatures gives the corresponding pyridones, possibly via the intramolecular reaction of a base - Cu(II) complex. Overall conversions are rather poor. 2- And 4-picolines and their methyl homologues undergo some demethylation under these conditions and some picolinic acid is isolated from 2-picoline. 2- And 4-ethylpyridines give both pyridine and 2- and 4-picoline, respectively.     

Katz Fractal Dimension of Geoelectric Field during Severe Geomagnetic Storms

We are concerned with the time series resulting from the computed local horizontal geoelectric field, obtained with the aid of a 1-D layered Earth model based on local geomagnetic field measurements, for the full solar magnetic cycle of 1996–2019, covering the two consecutive solar activity cycles 23 and 24. To our best knowledge, for the first time, the roughness of severe geomagnetic storms is considered by using a monofractal time series analysis of the Earth electric field. We show that during severe geomagnetic storms the Katz fractal dimension of the geoelectric field grows rapidly.     

Spectroscopic Measurements of Plasma Temperatures in a Radio Frequency Discharge

Argon and mixtures of argon with CH₄, C₂H₂ and N₂ have been excited in a 27.2 MHz radio frequency discharge at pressures of 10 and 5 Torr. Plasma spectra have been recorded and analyzed. The excitation temperatures of Ar I and H, the C₂ and CN vibrational temperatures and the N₂ and CN rotational temperatures have been determined and discussed.     

Synthesis and characterization of three new thermally stable N-heterocyclic germylenes

Three new stable germylenes, rac-1,3-di-tert-butyl-4,5-dimethyl-1,3-diaza-2-germacyclopentane-2-ylide (1), 1,3-di-tert-butyl-4,4-dimethyl-1,3-diaza-2-germacyclopentane-2-ylide (2), and rac-1,3,4-tri-tert-butyl-1,3-diaza-2-germacyclopentane-2-ylide (3) have been synthesized by the reaction of their corresponding germyl dichlorides with elemental lithium. Full synthetic procedures and characterizations are described.