Classical and Advanced Chemical Sciences
The crystal structure is reported for 2,7-dimethoxy-3-(1-naphthoyl)naphthalene (1), C23H17O3, one of β-aroylated naphthalene compounds. In crystal, two naphthalene ring moieties of respective molecules are non-coplanarly located to each other, and two molecules are nested inside one another through a pair of C–H···π hydrogen-bonding interactions (C–H···Cg = 2.73 Å) forming a dimeric molecular aggregate. Each dimeric molecular aggregate is linked with four adjacent dimers by regular-squarely directed four (sp3)C–H···OCH3 hydrogen bonds between the methoxy groups (C–H···O = 2.50 Å) forming two-dimensionally spread plane. The planes are stacked into piles of layers along ac diagonal. On the other hand, the β-aroylated naphthalene homologues, 3-benzoylated naphthalene derivative I and 3-(2-naphthoylated) one II, are proved to take unidimensional molecular accumulation. Though each dimeric molecular aggregate has four identical interactions between adjacent dimeric molecular aggregates in crystal of homologue I, the rectangular, i.e., non-regular-square aligned situation of four interactions makes the linkage of each aggregate with only two adjacent dimers resulting in ribbon structure. In crystal of homologue II, molecules are stacked without formation of dimeric aggregates in columnar structure. On the basis of the results of systematic comparison of molecular packing structure and effective noncovalent-bonding interactions among title compound 1 and the β- aroylated naphthalene homologues I and II, the presence of large difference in strength of intermolecular interactions, i.e., predominant or apparently sole functioning of either C–H···O hydrogen bond or C–H···π hydrogen-bonding interaction induces only unidimensional molecular accumulation, e.g., ribbon-like alignment composed of dimeric molecular aggregates or columnar assembling of molecules. 1H NMR spectra suggest that conformational interconversion behaviour of title compound 1 through rotation around two kinds of C–C bonds in solution is disturbed rather largely compared to two homologous compounds I and II. Spatial organization characteristics of single molecular and molecular packing structures of β-aroylated naphthalene homologues in crystal are comparatively analyzed along with those in solution for the sake of elucidation of relationship among spatial organization, noncovalent bonding intermolecular interaction in crystal, and steric factors in solution.
Keywords: Non-classical hydrogen-bonding interaction, molecular motif, dimeric molecular aggregates, two-dimensionally spread layer
A series of Cu-Ni tartarate composites at various compositions is prepared and used as green catalyst for the synthesis of quinoline and dihydropyrimidine derivatives. Time required for the completion of reaction using such new catalyst is comparatively less and affording high percentage yield of products.
Keywords: Cu-Ni-Tartarate, composites, catalysts, quinolines, Biginelli reaction, dihydropyrimidines
7-Methyltetrazolo[1,5-a]quinoline-4-carbaldehyde (1) was reacted with thiosemicarbazide to give the appropriate thiosemicarbazone (2). Compound (2) was reacted with different α-halocarbonyl compounds such as phenacyl bromide, hydrazonoyl chlorides and α-chloroacetic acid to afford thiazoles (4), aryldiazenylthiazoles (6), and thiazolidin-4-one (8), respectively. A series of 7-methyltetrazolo[1,5-a]quinoline derivatives, such as 2-imino-2H-chromene (11), arylacrylohydrazides (13), (15) and (17) and (heteroarylethylidene) acrylohydrazides (19), (21) and (23) has been synthesized. The structures of the newly synthesized compounds have been confirmed by spectral and elemental analyses.
Keywords: Tetrazolo[1,5-a]quinoline-4-carbaldehyde, hydrazonoyl chlorides, thiazole, chromene
Materials and Environmental Chemistry
Biomasses have significant impact on the development of new solid phase extraction methods for metal analysis. Adsorbent, prepared by incorporating dried biomass (Aspergillus oryzae) immobilized on activated silica, was presently developed for Au(III) enrichment. The main factors affecting the adsorption-desorption process like pH, sample volume, eluent and eluent flow rate were optimized. Under the optimum conditions, good recovery was obtained at about 99.4 ± 0.1 %, performed by Flame Atomic Absorption Spectrometry. At optimized pH 2.0, Au(III) was quantitatively sorbed and recovered with 1:1 mixture of 0.2 M HCl mixed with 0.2 M thiourea. The enrichment factor was found as 125, and the limit of detection is 0.88 μg L-1 whereas limit of quantification is 2.93 μg L-1. The proposed method was successfully applied in the analysis of tap water, pharmaceutical formulated product and synthetically prepared dummy sample. Equilibrium data also were fitted by linear regression methods through Langmuir, Freundlich, Temkin, Dubinin and Radushkevich (D–R) and Harkin –Jura isotherm models.
Keywords: Pharmaceutical formulated product, Aspergillus oryzae, immobilization, atomic absorption spectroscopy, solid phase extraction
In this study the assessment of water quality of two water resources (depth 10-50 meters) in the municipality of Kamenica have been investigated. Concentrations of some ions are determined using UV-VIS spectrometry. Statistical studies have been carried out by calculating of basic statistical parameters and anomalies (extremes and outliers). By comparing with available results of three similar water -samples in Kosovo, it can be summarized that water quality of two water-samples in the municipality of Kamenica is similar to the well waters of Mirosala. From the results of field work and laboratory analyses it was found out that the well water does not fulfil the criteria set by the WHO. The high value of Fe, Mn and turbidity pollutants indicated pollution by natural pollutants and from anthropogenic sources like waste waters.
Keywords: Quality assessment, well water, outliers, Kamenica, UV-VIS spectrometry
The indiscriminate land disposal of wastewater sludge in Lesotho poses an environmental and health concern since sludge typically contains a myriad of hazardous chemicals. This study characterised the physico-chemical properties of the sludge generated at the Ratjomose Wastewater Treatment Plant in Maseru, the capital city of Lesotho and its chemical safety for application on land as an organic fertilizer. The sludge was slightly acidic and had considerable amounts of macronutrients The heavy metal concentrations are less than the maximum limits recommended by the Food and Agricultural Organization and the South African standards for sludge applied to agricultural land and are slightly higher than those recommended in the national industrial effluent discharge standards in Lesotho. Principal component analysis did not reveal any major differences between the different cells used in the treatment plant. Since the nutrients and chemical composition of this sludge match the guidelines for an organic-mineral soil conditioner, it can be concluded that this sludge is safe for use in agricultural soils with no expected negative effects.
Keywords: Waste water sludge, chemical toxicity, nutrient content, bio-fertilizer, soil application, Lesotho
Chemical and Biological Aspects of Life
Effects of short-term seed treatments with multi-walled carbon nanotubes (MWCNTs) on seedling development in soil culture and of rootexposure in hydroponics were studied on soybean, considered as model plant system. At 8 days after sowing and in later stages of seedling development, stunted growth and poor fine root production were detected. More detailed investigations revealed zinc (Zn) deficiency as a major growth-limiting factor. The growth of affected plants was recovered by foliar application of ZnSO4 or by cultivation in nutrient solution supplied with soluble ZnSO4. Since Zn is an important co-factor of enzymes involved in detoxification of reactive oxygen species (ROS), such as copper-zinc superoxide dismutases, stunted plant growth in response to MWCNTs treatments may be related to oxidative damage associated with lipid peroxidation and excessive oxidative degradation of auxin as growth hormone important for lateral root formation and leaf expansion.
Keywords: soybean, common bean, maize, seedling development, nutrient availability, multi-walled carbon nanotubes, nanomaterials
Hypothalamic neurosecretory cytokine, proline-rich peptide-1 (PRP-1) may protect against myocardial dysfunction and hypocalcemia induced by experimental pancreatic necrosis (PN) and/or crush syndrome (CS). 24 and 48 h after initiation of experimental PN, effective doses of PRP-1 were administered to adult Wistar male rats divided into groups corresponding to early, reparative, chronic, and chronic recurrent stages of PN. Similarly age and sex matched rats were immediately administered PRP-1 after 2 h of compression injury. The PRP-1 normalized the histopathological changes in cardiac tissues in the dynamics of both PN and CS. Study of 45Ca++ binding to the membrane proteins of cardiomyocyte sarcoplasmic reticulum (SR) showed that PRP-1 could prevent an impairment in the calcium binding ability of the Ca2+ depot proteins caused under pathological conditions. Besides, PRP-1 suppresses a PN and/or CS-induced compensatory manifestation the affinity to calcium of the 32-kDa SR membrane protein and restores its native properties. The results highlight new prospects over the functional implications of PRP-1 and its possible therapeutic potential for the treatment of patients at high risk of cardiovascular disease associated with different pathologies.
Keywords: Calcium binding proteins, cardiomyocytes, crush syndrome, hypothalamic proline rich peptide-1, pancreatic necrosis, sarcoplasmic reticulum