Cationic Divalent Metal Sites (M = Mn, Fe, Co) Operating As Both Nitrene-Transfer Agents And Lewis Acids Toward Mediating The Synthesis Of Three- And Five-Membered N-Heterocycles

The tripodal compounds [(TMG3trphen)MII-solv](PF6)2 (M = Mn, Fe, Co; solv = MeCN, DMF) and bipodal analogues [(TMG2biphen)MII(NCMe)x](PF6)2 (x = 3 for Mn, Fe; x = 2 for Co) and [(TMG2biphen)MIICl2] have been synthesized with ligands that feature a triaryl- or diarylmethyl-amine framework and superbasic tetramethylguanidinyl residues (TMG). The dicationic M(II) sites mediate catalytic nitrene-transfer reactions between the imidoiodinane PhI═NTs (Ts = tosyl) and a panel of styrenes in MeCN to afford aziridines and low yields of imidazolines (upon MeCN insertion) with an order of productivity that favors the bipodal over the tripodal reagents and a metal preference of Fe \u3e Co ≥ Mn. In CH2Cl2, the more acidic Fe(II) sites favor formation of 2,4-diaryl-N-tosylpyrrolidines by means of an in situ (3 + 2) cycloaddition of the initially generated 2-aryl-N-tosylaziridine with residual styrene. In the presence of ketone, 1,3-oxazolidines can be formed in practicable yields, involving a single-pot cycloaddition reaction of alkene, nitrene, and ketone (2 + 1 + 2). Mechanistic studies indicate that the most productive bipodal Fe(II) site mediates stepwise addition of nitrene to olefins to generate aziridines with good retention of stereochemistry and further enables aziridine ring opening to unmask a 1,3-zwitterion that can undergo cycloaddition with dipolarophiles (MeCN, alkene, ketone) to afford five-membered N-heterocycles

Effect of a three-component bacterial consortium in white shrimp farming for growth, survival and water quality management

The effect of a bacterial consortium containing Rhodopseudomonas palustris SUP-2, Bacillus subtilis SUP-3, and Bacillusfirmus SUP-1 strains for white shrimp (Penaeus vannamei) farming were investigated. Shrimp growth, water quality, survival rate and enzymatic activities were followed at different stages of farming. Consortium developed using equal proportion of each bacterium was added to shrimp ponds at different concentrations. Dosages were adjusted in three different stages, first 40 days (10 l/ha), second 40 days (15 l/ha) and then continued up to harvest (20 l/ha). Consortium was used in the experiment ponds and no consortium was used in the control ponds. The mean survival rates were significantly lower, 65.1 ± 1.4% and 67.8 ± 2.2% in control ponds BPC-1 and BPC-2 (P˂0.001), respectively. The statistical analysis showed significant differences (P<0.05) in the weight of the animals between the treatment (34.98 ± 0.1 in BTP 1 and 35.26 ± 0.1 g in BTP 2) and control (29.23 ± 0.1 in BCP 1 and 30.41 ± 0.1 in BCP 2) groups

What Explains India's Real Appreciation?

We examine the evolution of nontradable and tradable prices in the Indian economy over 1980-2002 and find widening differentials: the real exchange rate has been appreciating. This might seem unsurprising, since India''s rapid per capita income growth suggests Balassa-Samuelson factors at play. However, after 1990, the tradable-nontradable labor productivity gap, the driver of real appreciation according to Balassa-Samuelson, virtually disappeared. So what explains the real appreciation? Assessing the role of both demand and supply factors, we find that demand pressures arising from higher income growth accounted for much of the relative price increase during the post-reform period. Falling import prices also contributed significantly, along with an increase in government spending.Productivity;Real effective exchange rates;inflation, relative price, per capita income, terms of trade, nontradable goods, inflation rates, inflation rate, relative prices, import prices, real exchange rates, exchange rate regime, import liberalization, export growth, price liberalization, tradable goods, import price, accession countries, export share, exchange rate policy, export shares, metal products, trade liberalization, terms of trade shocks, price of imports, transition economies, real output, price level, political economy, transport equipment, gdp deflator, trade reforms, export prices, domestic price, imported inputs, trade shocks, rate of inflation, factor markets, value of exports, impact of trade liberalization, trade performance, price fluctuations, inflation convergence, export sectors, perfect integration, price inflation, oil shock, exchange rate movements, perfect competition, intermediate goods, aggregate consumption, impact of trade, producer price index, increasing competition, value of imports, increasing competitiveness, nontariff barriers, export industries, export price, import duty, domestic production, imported goods, effective exchange rates, monetary union

Facile synthesis of anion dependent versatile Cu¹ and mixed-valent porous Cu¹/Cu² frameworks

CuX<SUB>2</SUB> (X = ClO<SUB>4</SUB><SUP>-</SUP>, NO<SUB>3</SUB><SUP>-</SUP>, 0.5 SO<SUB>4</SUB><SUP>2−</SUP>, Cl<SUP>-</SUP>) and 2,3-dihydroxyfumaric acid (dhfa) undergo redox reaction in slightly basic aqueous solution forming Cu<SUP>I</SUP>X and 2,3-diketosuccinic acid. Pyrazine (pyz) and 1,2-bis(4-pyridyl)ethylene (bpee) linkers have been used for stabilizing and isolating the Cu<SUP>I</SUP> state in this reaction. The three different Cu<SUP>I</SUP>-frameworks, {Cu(pyz)<SUB>1.5</SUB>(ClO<SUB>4</SUB>)}<SUB>n</SUB> (1), u(pyz)(NO<SUB>3</SUB>)}<SUB>n</SUB> (2), and {[Cu(bpee)Cl]·2H<SUB>2</SUB>O}<SUB>n</SUB> (3) with different anions have been synthesized and structurally characterized. The framework topology and dimensionality depends upon the anions. This is a one step synthesis of Cu<SUP>I</SUP> coordination frameworks with 1:2 stoichiometry in relation to dhfa and Cu<SUP>II</SUP>. By controlling the concentration of dhfa, a mixed-valent porous Cu<SUP>I</SUP>/Cu<SUP>II</SUP> framework, [Cu<SUP>II</SUP>Cu<SUP>I</SUP><SUB>2</SUB>(2,4-pyrdc)<SUB>2</SUB>(pyz)<SUB>3</SUB>]·2H<SUB>2</SUB>O}<SUB>n</SUB> (4) has been synthesized and characterized by XPS and magnetic studies. Dehydrated frameworks of 3 and 4 exhibit interesting sorption properties with different solvent molecules. In a similar reaction CuCl<SUB>2</SUB> and pyz without dhfa produced the corresponding Cu<SUP>II</SUP>-compound, {Cu(pyz)Cl<SUB>2</SUB>}<SUB>n</SUB> (5), suggesting the reducing role of dhfa. Therefore by this simple reaction, it is possible to control the oxidation state as well as the coordination number and geometry of Cu ions. This is a novel synthetic methodology for the stabilization of the Cu +1 state in aqueous solution and open atmosphere

Green synthesis of catalytic and ferromagnetic gold nanoparticles

A facile and green method has been developed to synthesize gold nanoparticles using a novel reducing agent 2,3-dihydroxyfumaric acid (DHFA). PVP stabilized gold nanoparticles show excellent catalytic activity for controlled and complete aerial oxidation of hydroxybenzylalcohols to hydroxybenzaldehydes. Uncapped gold nanoparticles are ferromagnetic in nature at room temperature

Magnetically Frustrated Quaternary Chalcogenides with Interpenetrating Diamond Lattices

A series of quaternary sulfides of the composition Na3MGaS4 (M = Mn (1), Fe (2), and Co (3)) have been synthesized in sealed quartz ampules. In these compounds, divalent transition metal and Ga occupy the same crystallographic site in the Ga-S network, forming a supertetrahedral, T2 (adamantane) unit, through the corner-sharing of four M/GaS4 tetrahedra. The corner sulfur atoms of the T2 clusters are further connected to similar T2 units to form an open continuous three-dimensional (3D) anionic framework of composition {[Ga2M2S8]n}6-. The framework resembles a zinc blende structure type if each T2 cluster is considered as a single tetrahedron and two such frameworks are intertwined to generate channels wherein reside the extra-framework Na+ ions. Placement of transition metals (Mn or Fe or Co) in the corner of a perfect supertetrahedron, adamantane building unit, generates an ideal lattice for geometrical magnetic frustration, which, on dilution with nonmagnetic metal (Ga), creates an ideal case for random frustration. Preliminary magnetic measurements indicate high negative values of the Weiss constant (-200 to -400 K) and the absence of any magnetic ordering, reinforcing the presence of magnetic frustration in all of these compounds

Temperature-Dependent Semiconducting Behavior of an Organic Cocrystal Driven by the Stacking Mode of Interaction of a 4,4′-Bipyridine Molecule

Organic cocrystals based on H-bonding as well as π-stacking interactions between 4,4′-bipyridine–pyromellitic acid (1) and 4,4′-bipyridine–phthalic acid (2) are reported. Cocrystals 1 and 2 were fully characterized by single-crystal X-ray diffraction and NMR and IR spectroscopy. The single-crystal X-ray diffraction shows the H stacking pattern of the adjacent 4,4′-bipyridine molecules in the construction of a 3D chain structure for cocrystal 1. Cocrystal 2, however, formed a zigzag 3D chain where the adjacent 4,4′-bipyridyl molecules are involved in a J-stacking mode. Experimental conductivity measurements of the cocrystals 1 and 2 with a Keithley 4200 SCS parameter analyzer showed the temperature-dependent semiconducting behavior in the case of cocrystal 1, whereas cocrystal 2 remained as an insulator. The favorable H-stacking interaction of 4,4′-bipyridine molecules which is the prime origin of semiconductivity in cocrystal 1 may become out of phase due to the free rotation along the C–C bond of 4,4′-bipyridine with an increase in temperature. Although the semiconducting behavior of a material increases with increasing temperature and decreases in resistivity, in the case of cocrystal 1 due to the probable phase transition of the 4,4′-bipyridyl molecules the material became an insulator with an increase in temperature from 20 °C to higher temperature, whereas the semiconducting behavior was restored after cooling the crystals to 20 °C again. The theoretical study conducted with the optimized structures of 1 and 2 showed the higher electron hopping rate in the case of cocrystal 1 as compared to 2 which can account for the charge conduction in the case of 1

A Series of Trifacial Pd6 Molecular Barrels with Porphyrin Walls

supramolecular chemistr