Structural identification of two differently coordinated heptamolybdate ligands in a hexamagnesium compound

517-525Dissolution of freshly prepared molybdenum trioxide in hot aqueous magnesium carbonate followed by crystallization results in the formation of an all-inorganic heptamolybdate compound viz. [Mg(H2O)6]3[Mg(H2O)5(Mo7O24)][(H2O)5Mg (µ2-Mo7O24)Mg(H2O)5]∙6H2O (1). The crystal structure, spectral characteristics, thermal and electrochemical properties of 1 are reported. Compound 1, which crystallizes in the acentric polar space group Cc, contains six unique Mg(II) ions. The two crystallographically independent heptamolybdate anions function as a monodentate (η1) and µ2-bridging bidentate ligand, respectively, forming the anionic [Mg(H2O)5(Mo7O24)]4− and [(H2O)5Mg(µ2-Mo7O24)Mg(H2O)5]2− species, which are charge balanced by three unique hexaaquamagnesium(II) cations. The electrochemical and conductivity studies of 1 reveal the presence of [Mg(H2O)6]2+ cations and uncoordinated (Mo7O24)6− anions in solution. Thermal decomposition of 1 leads to the formation of Mg2Mo3O11 via Mg6Mo14O48 and 3Mg2Mo3O11∙5MoO3

Synthesis and structure of a mixed ligand copper(II) compound based on a distorted {CuN2O3} square pyramid

499-505The synthesis, spectra, thermal study and crystal structure of a mixed ligand copper(II) compound viz. [Cu(biq)(acac)(NO3)] 1 (biq = 2,2′-biquinoline, acac = acetylacetonate) are reported. The {CuN2O3} coordination sphere is made up of two oxygen atoms of an unique acac ligand, an oxygen of the nitrate group and one N atom of biq ligand which form the basal plane {CuNO3} of a square pyramid. A second nitrogen atom of the biq ligand occupies the apical position resulting in a distorted square pyramidal {CuN2O3} polyhedron. In the crystal structure, each neutral square pyramidal copper(II) species is linked with two symmetry related molecules with the aid of intermolecular C-H...O hydrogen bonding interactions. A study of fifteen mixed ligand copper(II) acetylacetonates reveals that in this series of compounds, 1 exhibits maximum deviation of the {CuN2O3} polyhedron from square pyramidal towards trigonal bipyramidal geometry

Synthesis and structure of a mixed ligand copper(II) compound based on a distorted {CuN2O3} square pyramid

The synthesis, spectra, thermal study and crystal structure of a mixed ligand copper(II) compound viz. [Cu(biq)(acac)(NO3)] 1 (biq = 2,2′-biquinoline, acac = acetylacetonate) are reported. The {CuN2O3} coordination sphere is made up of two oxygen atoms of an unique acac ligand, an oxygen of the nitrate group and one N atom of biq ligand which form the basal plane {CuNO3} of a square pyramid. A second nitrogen atom of the biq ligand occupies the apical position resulting in a distorted square pyramidal {CuN2O3} polyhedron. In the crystal structure, each neutral square pyramidal copper(II) species is linked with two symmetry related molecules with the aid of intermolecular C-H×××O hydrogen bonding interactions. A study of fifteen mixed ligand copper(II) acetylacetonates reveals that in this series of compounds, 1 exhibits maximum deviation of the {CuN2O3} polyhedron from square pyramidal towards trigonal bipyramidal geometry.

Synthesis, structure and properties of a hexarubidium heptamolybdate with bridging aqua ligands

The synthesis, single crystal structure, spectral, thermal and electrical properties of a hexarubidium heptamolybdate [Rb6(H2O)4(Mo7O24)] 1 is reported. The bridging binding modes of the unique (Mo7O24)6- ion and the four crystallographically independent coordinated water molecules results in coordination numbers ranging from 8 to 10 for the six unique Rb(I) ions in 1. Thermal decomposition of 1 results in the formation of an anhydrous residue of composition 7MoO3·3Rb2O. The cyclic voltammogram of an aqueous solution of 1 exhibits a single redox event characteristic of (Mo7O24)6- anion. Solution conductivity studies reveal the presence of hydrated Rb+ cations and uncoordinated (Mo7O24)6- anions. A comparative study of several alkali-metal heptamolybdates reveals a rich structural chemistry in terms of the binding modes of the (Mo7O24)6- anion

Photo-tautomerization of acetaldehyde as a photochemical source of formic acid in the troposphere

Organic acids play a key role in the troposphere, contributing to atmospheric aqueous-phase chemistry, aerosol formation, and precipitation acidity. Atmospheric models currently account for less than half the observed, globally averaged formic acid loading. Here we report that acetaldehyde photo-tautomerizes to vinyl alcohol under atmospherically relevant pressures of nitrogen, in the actinic wavelength range, λ = 300–330 nm, with measured quantum yields of 2–25%. Recent theoretical kinetics studies show hydroxyl-initiated oxidation of vinyl alcohol produces formic acid. Adding these pathways to an atmospheric chemistry box model (Master Chemical Mechanism) demonstrates increased formic acid concentrations by a factor of ~1.7 in the polluted troposphere and a factor of ~3 under pristine conditions. Incorporating this mechanism into the GEOS-Chem 3D global chemical transport model reveals an estimated 7% contribution to worldwide formic acid production, with up to 60% of the total modeled formic acid production over oceans arising from photo-tautomerization

Response of cowpea [Vigna unguiculata (L.) Walp] genotypes under residual moisture condition in rice-fallow area of Goa state, India.

Not Availablefield experiment was conducted during rabi season 2018-19 to study the response of 23 cowpea genotypes grown under residual moisture condition in rice-fallow situation of Goa state. Analysis of variance revealed significant differences among the genotypes for all the eleven characters, justifying the selection of genotypes for the study. The estimate of Phenotypic Coefficient of Variation (PCV) and Genotypic Coefficient of Variation (GCV) were high (>20%) for seed yield, straw yield, pods per plant and 100 seed weight. Heritability and genetic advance as per cent mean estimates were high for most of the characters except for days to 50 per cent flowering, days to maturity and plant height. Characters plant height, pods per plant, straw yield and harvest index showed positive and significant association with seed yield. Path analysis based on seed yield, as a dependent variable, revealed that straw yield and harvest index had the highest positive direct effect on seed yield. Therefore, maximum importance should be given to these traits during the selection for achieving the higher seed yield under rice-fallow situation. Three promising genotypes identified from this study viz., PCP-1131, SKAU-C- 407 and RC 101 would serve as dual-purpose cowpea under rice-fallow areas due to their high seed yield and straw yield.Not Availabl

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Not AvailableThe present investigation was undertaken to assess the hybridity of experimental F1 plants derived from the crossing of salinity and/or submergence tolerant landraces with the high-yielding popular varieties of the west coast region of India. Seven microsatellite markers were utilized for confirming the hybridity of the 16 F1 plants developed from four cross combinations, viz. Karjat-3 X KS-19-2 (Cross 1), Goa dhan-3 X Jaddubatta (Cross 2), Jaya X KS-19-2 (Cross 3) and Karjat-3 X Jaddubatta (Cross 4). Polymorphism survey using above seven markers between the parents of all the four crosses revealed that six of them were polymorphic, whereas one marker was monomorphic. The marker RM21539 was found to be polymorphic in all the four cross combinations, followed by RM493, RM3412, RM206 and RM10843 exhibiting polymorphism in three crosses, while marker RM25181 was polymorphic in two crosses. The screening of F1s with polymorphic markers revealed that the F1s from Cross 3 exhibited heterozygosity (showing alleles from both the parents) at six marker loci, whereas the F1s from Cross 1 and Cross 4 at five loci and Cross 2 at two marker loci, thereby confirming hybridity in all the 16 tested F1 plants.Not Availabl

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Not AvailableSoil quality (SQ) under any agriculture system is greatly influenced by source of nutrients, type of soil, crop, and their management practices. In this regard, a field experiment was conducted under lowland rice production system for 5 years to assess the effect of nutrient management with organic and inorganic nutrient on soil quality. The nutrient management practices studied were: FYM: farmyard manure (10 t ha−1), Verm: vermicompost (5 t ha−1), GE: Gliricidia and Eupatorium (each 5 t ha−1), PW: Paddy straw and water hyacinth (each 5 t ha−1), SR: Dhaincha (10 t ha−1), RDF-NPK: recommended dose of fertilizers (100:50:50 NPK kg ha−1), and control. The effect of different nutrient management practices on the soil properties, grain yield, sustainable yield index, and soil quality index were evaluated. The nutrient management practices affected the soil properties, rice grain yield, and sustainable yield index significantly. Phosphatase activity, soil organic carbon, microbial biomass carbon, available phosphorus, and nitrogen were selected for minimum data set using principal component analysis. Their corresponding average contribution to the soil quality index was 70.7, 7.92, 8.67, 1.69, and 10.9%, respectively. The soil quality index obtained by integrating the minimum data set and employing non-linear scoring function varied from 0.72 (SR) to 0.99 (FYM) and it was minimum in the control (0.68). The FYM improved the SQ by 28.5 and 45.5% over RDF-NPK and control, respectively. Using organic sources of nutrients under transplanted rice improves the soil quality and sustainability by improving plant growth and soil functions.Indian Council of Agricultural Researc

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Not AvailableSalt stress is a major abiotic stress affecting the productivity of rice crop worldwide. This study screened a set of 71 rice genotypes collected from coastal parts of Goa and Karnataka states in India for seedling stage salinity tolerance to identify genotypes alternative to standard salt-tolerant donors Pokkali, FL478, etc. Phenotyping for seedling stage tolerance was carried out under micro plots at an induced salinity of 12 dS/m. For haplotyping, 14 Saltol QTL linked simple sequence repeat (SSR) markers on chromosome 1 were utilized. On the basis of the response to salt stress, 10 genotypes were found tolerant, 16 moderately tolerant, 29 sensitive and 15 as highly sensitive. Among the SSR markers, marker RM10871 was the most polymorphic with a polymorphic information content of 0.90, exhibiting 14 different alleles followed by RM10793 (0.84) and RM3412 (0.80) with 8 and 7 alleles, respectively. These markers also exhibited high values for the effective number of alleles (Ne) and gene diversity (I). The haplotype analysis revealed that the allelic constitution of the Saltol region of 10 tolerant genotypes from our study varied in comparison to the reference tolerant check FL478. Further, the haplotype of three tolerant genotypes, namely, Goa Dhan 2, Panvel 1 and Goa wild rice (GWR) 005 appears to be completely different from the FL478 haplotype indicating tolerance in these genotypes is controlled by genomic region other than Saltol. These three genotypes with probable novel regions for seedling stage salt tolerance can be considered for enhancing salinity tolerance of rice cultivars.Not Availabl

Synthesis, structure and properties of a hexarubidium heptamolybdate with bridging aqua ligands

601-609The synthesis, single crystal structure, spectral, thermal and electrical properties of a hexarubidium heptamolybdate [Rb6(H2O)4(Mo7O24)] 1 is reported. The bridging binding modes of the unique (Mo7O24)6- ion and the four crystallographically independent coordinated water molecules results in coordination numbers ranging from 8 to 10 for the six unique Rb(I) ions in 1. Thermal decomposition of 1 results in the formation of an anhydrous residue of composition 7MoO3·3Rb2O. The cyclic voltammogram of an aqueous solution of 1 exhibits a single redox event characteristic of (Mo7O24)6- anion. Solution conductivity studies reveal the presence of hydrated Rb+ cations and uncoordinated (Mo7O24)6- anions. A comparative study of several alkali-metal heptamolybdates reveals a rich structural chemistry in terms of the binding modes of the (Mo7O24)6- anion