Raman,FT‐IR,and DFT studies of 3,5‐pyrazoledicarboxylic acid and its Ce(III) and Nd(III) complexes

3,5‐Pyrazoledicarboxylic acid was used as a ligand for the synthesis of its Ce(III) and Nd(III) complexes. The complexes of Ce(III) and Nd(III) with 3,5‐pyrazoledicarboxylic acid were synthesized and their compositions were determined by elemental analysis. Vibrational study in the solid state of 3,5‐pyrazoledicarboxylic acid and its new Ce(III) and Nd(III) complexes was performed by IR and Raman spectroscopy. The changes observed between the IR and Raman spectra of the ligand and of the complexes allowed us to establish the coordination mode of the metal in both complexes. The comparative vibrational analysis of the free ligand and its lanthanide(III) complexes gave evidence that 3,5‐pyrazoledicarboxylic acid binds Ln(III) through the deprotonated carboxylic oxygens. The density functional theory (DFT) calculated geometries, harmonic vibrational modes and Raman scattering activities of the ligand were in good agreement with the experimental data, and a complete vibrational assignment is being proposed. The experimental IR and Raman bands of the ligand were assigned to normal modes on the basis of DFT calculations. The effect of the intramolecular hydrogen bonds in the ligand on vibrational mode positions is also discussed. The characteristic IR and Raman bands of 3,5‐pyrazoledicarboxylic acid and its lanthanide complexes were specified and discussed. Copyright © 2006 John Wiley & Sons, Ltd.     

Estrone derived 2-naphthol analogue in the diastereoselective one-pot Betti-condensation

Molecular Diversity - The utility of deoxy-isoequilenine synthesized from estrone as valuable 2-naphthol analogue is demonstrated in the three components Betti-condensation. A simple, efficient and...     

Synthesis,Structure and Impact of 5-Aminoorotic Acid and Its Complexes with Lanthanum(III) and Gallium(III) on the Activity of Xanthine Oxidase

The superoxide radical ion is involved in numerous physiological processes, associated with both health and pathology. Its participation in cancer onset and progression is well documented. Lanthanum(III) and gallium(III) are cations that are known to possess anticancer properties. Their coordination complexes are being investigated by the scientific community in the search for novel oncological disease remedies. Their complexes with 5-aminoorotic acid suppress superoxide, derived enzymatically from xanthine/xanthine oxidase (X/XO). It seems that they, to differing extents, impact the enzyme, or the substrate, or both. The present study closely examines their chemical structure by way of modern methods—IR, Raman, and ¹H NMR spectroscopy. Their superoxide-scavenging behavior in the presence of a non-enzymatic source (potassium superoxide) is compared to that in the presence of an enzymatic source (X/XO). Enzymatic activity of XO, defined in terms of the production of uric acid, seems to be impacted by both complexes and the pure ligand in a concentration-dependent manner. In order to better relate the compounds’ chemical characteristics to XO inhibition, they were docked in silico to XO. A molecular docking assay provided further proof that 5-aminoorotic acid and its complexes with lanthanum(III) and gallium(III) very probably suppress superoxide production via XO inhibition.     

Structure of white cement mortars with high content of marble powder

In this study, three types of cementitious composites based on (i) white Portland cement and sand (cement-to-aggregate 1:3, and water-to-cement 0.50), (ii) white Portland cement and marble powder (cement-to-aggregate 1:2, and water-to-cement 0.60), and (iii) white Portland cement and marble powder with polycarboxylate-based admixture (HRWR) (cement-to-aggregate 1:2, and water-to-cement 0.40?+?HRWR) were studied. Their states after 28 and 120?days of water curing were evaluated by measurement of physical?Cmechanical properties, such as density, compressive strength and porosity. Thermal analysis, X-ray diffraction analysis and scanning electron microscopy were used to identify the crystal phases and their morphology. The experimental data show that the white cement mortars with higher water content exhibit larder variety of newly formed phases, like hydration products of the C?CS?CH type. The structure of mortars with polycarboxylate-based admixture is so dense that there is no possibility of crystal hydrates development at late curing ages. The use of marble as filler leads to a partial inclusion of carbonate ions in the newly formed hydrated phases (carbo-aluminates).     

Extraction-spectrophotometric study of the system manganese(VII)-methyl violett-water-chloroform and its application

The system manganese(VII)-methyl violet(MV)-water-chloroform has been studied. The composition of the complex is established as MV: MnO₄⁻=1:1. The molar absorptivity of the complex is (2.67 ± 0.09) × 10⁴ l mol⁻¹ cm⁻¹ at 300 nm, limit of detection is 0.027 μg ml⁻¹ and the system obeys Beer’s law in the range 0.22–1.6 μg ml⁻¹ Mn(VII). The characteristic values for the extraction equilibrium and the equilibrium in the aqueous phase was determined. The influence of foreign ions on the accuracy of the results is investigated. Extraction investigations of the system discussed were carried out. A new rapid, selective, simple and sensitive extractive-spectrophotometric method for the determination of trace amounts of manganese(VII) in plants, soils and steels were developed.     

1-Norbornyllithium as a Precursor for the Synthesis of Novel Organic 1-Bicyclo[2.2.1]Heptane Derivatives and for the Improved Preparation of 1-Chloro-Bicyclo[2.2.2]octane

An improved strategy for synthesis of 1-chloro-bicyclo[2.2.2]octane is described in which the key compounds 1-norborny substituted ethyl formate(3) or 1-norbornylcarbaldehyde (7) were prepared from 1-norbornyllithium(1). The latter appeared as a useful precursor for the synthesis of various organic bridgehead substituted derivatives.     

Extraction-spectrophotometric and radiometric investigation of the ternary ion-association complex of niobium(V) with pyrocatechol and triphenyl-tetrazolium chloride

The optimum conditions for extraction of niobium(V) as a ternary ion-association complex with pyrocatechol and triphenyltetrazolium chloride(TTC) have been determined. The investigation of the composition has shown that the ratio Nb:proocatechol:TTC is 1:2:1 K_ex, K_D and have been determined radiometrically, using the chemical model. The influence of foreign ions on the extraction of the ion-association complex has been studied. A method for artifical mixture and steel containing niobium has been used.     

Lifetime measurements and particle-core coupling calculations in144Sm

Applying the generalized centroid shift method in the¹⁴²Nd(α, 2n)¹⁴⁴Sm reaction the following half-lives have been measured:T _1/2(3,376 keV)=(1.6±0.2) ns,T _1/2(3,460 keV) =(0.5±0.2) ns andT _1/2(5,150 keV)≦0.3 ns. Level energies and electromagnetic transition rates have been calculated within a particle-core coupling approach that is based on the shell model with configuration mixing. The persistence ofl-forbiddenness of M1 transitions between rather complex configurations could be confirmed.     

Synthese von Tetradecano-14-lacton durch Ringerweiterung

Synthesis of Tetradecano-14-lactone by Ring Enlargement The aldehyde 3 , prepared by ozonolysis of 2-allyl-2-nitrocyclododecanone, gave the ring-enlargement product 5 (85%) by treatment with (i-Bu)₂AlH. Its transformation to the tetradecano-14-lactone ( 8 ) via the aldol ester 6 and other routes (best is reduction with Bu₃SnH, AlBN, toluene) was difficult. Remarkable is the smooth denitrification of 3 (loss of HNO₂) to the conjugated dione 4 by chromatography on silica gel or base treatment.