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Bimetallic nanoparticles, particularly those based on copper, have recently attracted a great deal of attention for the development of low cost and highly active catalysts due to the synergistic interaction between individual metal components. In this work, bimetallic Ag–Cu alloy nanoparticles were explored as a highly active and reusable catalyst for the enamination of 1,3-dicarbonyls using diverse amines. The nanocatalysts were intensively characterized by ultraviolet-visible (UV-Vis) spectroscopy, X-ray diffraction (XRD), high-resolution transmission electron microscopy-energy-dispersive spectroscopy (HRTEM-EDS) and valence band and core level X-ray photoelectron spectroscopy (XPS) to study the effect of the bimetallic structure and composition. In comparison to monometallic Ag and Cu nanoparticles, the alloyed Ag–Cu nanoparticles showed a high catalytic performance and the resultant catalytic activity was dependant on the Ag to Cu ratio. This enhanced catalytic activity should be related to the electronic interaction between Ag and Cu nanoparticles formed due to the intimate contact between them. Our study may serve as a foundation for designing efficient alloyed nanocatalysts for fine chemical synthesis via enamination reactions.

A tandem one pot reaction involving gem-dichlorination, hydrolysis and nitrile oxide generation from 7-alkoxy-4-chloro-2,2-dimethyl-2H-chromene-6-carbaldehyde oxime followed by olefin/alkyne cycloaddition has been carried out in good yield at ambient temperature using open flask chemistry. The synthesized 4-chromanone derivatives show conformational isomerism as determined by VT 1H-NMR, confirmed by X-ray crystallography and explained by DFT calculations. This can be a general method for C-3 electrophilic chlorination of benzopyran derivatives.

Aprocess for the assembly of carbazole alkaloids has been developed on the basis of ring-closing metathesis (RCM) and ringrearrangement-aromatization (RRA) as the key steps. This method is based on allyl Grignard addition to isatin derivatives to provide smooth access to 2,2-diallyl 3-oxindole derivatives through a 1,2-allyl shift. The diallyl derivatives were used as RCM precursors to afford a novel class of spirocyclopentene-3-oxindole derivatives, which underwent a novel RRA reaction to afford carbazole derivatives. The synthetic sequence to carbazoles was shortened by combining the RCM and RRA steps in an orthogonal tandem catalytic process. The utility of this methodology was further demonstrated by the straightforward synthesis of carbazole alkaloids, including amukonal derivative, girinimbilol, heptaphylline, and bis(2-hydroxy-3-methylcarbazole).

This paper highlights recent developments in the design and construction of functional materials such as supramolecular hydrogels and ion channels using a guanine motif as a self-assembling building block.

The potential medicinal applications of boron-based compounds have been well established. Among the medicinal applications of boron, its use for the treatment of cancer via boron neutron capture therapy (BNCT) is the most promising. Although a variety of approaches have been evaluated for adequate boron delivery to the cancer tissues for successful cancer therapy, this review focuses on the synthesis of carbohydrate-based boron delivery platforms. Recent advances in the synthesis and utilization of glycoconjugates for boron delivery has been reported.

Potassium tert-butoxide acts as a nucleophilic oxygen source during the hydration of nitriles to give the corresponding amides under anhydrous conditions. The reaction proceeds smoothly for a broad range of substrates under mild conditions, providing an efficient and economically affordable synthetic route to the amides in excellent yields. This protocol does not need any transition-metal catalyst or any special experimental setup and is easily scalable to bulk scale synthesis. A single-electron-transfer radical mechanism as well as an ionic mechanism have been proposed for the hydration process.

Tubuvalin derivatives are prepared by a regio- and enantioselective L-proline-catalyzed aldol reaction of thiazole carbaldehydes with acetone and a corresponding prolinamide-catalyzed transformation of 2-formylthiazole-4-carboxylate with methylisopropyl ketone on water.

An uncatalyzed aldol reaction of N-substituted thiazolidinediones with isatin derivatives has been developed “on water” to afford a new class of pharmacologically important thiazolidinedione–isatin conjugates in excellent yields and diastereoselectivities. The isatin–thiazolidine conjugate undergoes a catalyst-free stereoselective transfer aldol reaction on water. Single-crystal X-ray studies reveal that the aldol products can self-assemble to form supramolecular DNA “zipper” like structures through intermolecular hydrogen bonds and aromatic π–π interactions.

Regioselective dimerization of terminal aryl alkynes to produce conjugated enynes has been achieved using FeCl3 and KO(t)Bu in the presence of either DMEDA or dppe. The reaction proceeds smoothly in toluene at 145 °C for 2 h to give the corresponding head-to-head dimers in good to excellent yields (54 to 99%) with high E-selectivity (67 : 33 to 83 : 17 E/Z). Both strongly electron-donating and electron-withdrawing groups are compatible with this procedure. The bidentate phosphine (dppe) ligand exhibits better catalytic activity than the bidentate amine (DMEDA). The aliphatic acetylene fails to react under this catalytic system which suggests that potassium tertiary butoxide activates the conjugated system of aryl acetylene through cation-pi interaction and pi-pi interaction. A radical inhibitor (galvinoxyl or TEMPO) completely suppresses the reaction. Employing FeCl2 as a catalyst instead of FeCl3, only phenyl acetylene afforded the corresponding head to head dimer in good yield. Mechanistic pathways for both FeCl3 catalyzed dimerization of aryl alkynes and FeCl2 catalyzed dimerization of phenyl acetylene have been proposed.

Several strategies for the effective separation of (99m)Tc from (99)Mo have been developed and validated. Due to the success of column chromatographic separation using acidic alumina coupled with high specific activity fission (99)Mo (F (99)Mo) for production of (99)Mo/(99m)Tc generators, however, most technologies until recently have generated little interest. The reduced availability of F (99)Mo and consequently the shortage of (99)Mo/(99m)Tc column generators in the recent past have resurrected interest in the production of (99)Mo as well as (99m)Tc by alternate routes. Most of these alternative production processes require separation techniques capable of providing clinical grade (99m)Tc from low specific activity (99)Mo or irradiated Mo targets. For this reason there has been renewed interest in alternate separation routes. This paper reviews the reported separation technologies which include column chromatography, solvent extraction, sublimation and gel systems that have been traditionally used for the fabrication of (99)Mo/(99m)Tc generator systems. The comparative advantage, disadvantage, and technical challenges toward adapting the emerging requirements are discussed. New developments such as solid-phase column extraction, electrochemical separation, extraction chromatography, supported liquid membrane (SLM) and thermochromatographic techniques are also being evaluated for their potential application in the changed scenario of providing (99m)Tc from alternate routes. Based on the analysis provided in this review, it appears that some proven separation technologies can be quickly resurrected for the separation of clinical grade (99m)Tc from macroscopic levels of reactor or cyclotron irradiated molybdenum targets. Furthermore, emerging technologies can be developed further to respond to the expected changing modes of (99m)Tc production.

In the reactions of 2,3-pyrazinedicarboxylic anhydride with amines and anilines, pyrazine carboxamides are formed in good to excellent yields. A mechanism is proposed involving ring opening of the anhydride and decarboxylation of the heterocyclic ring. Based on other similar heterocyclic decarboxylations, this suggests the involvement of an N-heterocyclic carbene intermediate leading to the product.

The novel prolinamide catalyst shows excellent isolated yields, enantioselectivities, and diastereoselectivities for the title reaction.

Thiazolidinediones have been used as aldol donors with aromatic aldehydes “on water” and in DMSO without using any catalyst to give the corresponding β-hydroxy carbonyl compounds in high yield and purity. The p-cyano and p-nitro substituted aldol products undergo syn/anti isomerization via an enolization mechanism providing an “on water” diastereoselectivity switch. Water molecules play a significant role in stabilizing the syn aldol products of pyridine and thiazole containing aldehydes.

Melithiazole G (VII) is prepared via a sequence involving cross-metathesis of alkenes (I) and (II), asymmetric transfer hydrogenation of olefin (IV), and Stille coupling reaction of bromide (III) as the key steps.

Selective N- and C-alkenylation of hydantoin followed by metathesis allows an easy and efficient access to various spirocyclic and fused bicyclic hydantion derivatives.

The last decade has witnessed enormous research focused on cationic polymers. Cationic polymers are the subject of intense research as non-viral gene delivery systems, due to their flexible properties, facile synthesis, robustness and proven gene delivery efficiency. Here, we review the most recent scientific advances in cationic polymers and their derivatives not only for gene delivery purposes but also for various alternative therapeutic applications. An overview of the synthesis and preparation of cationic polymers is provided along with their inherent bioactive and intrinsic therapeutic potential. In addition, cationic polymer based biomedical materials are covered. Major progress in the fields of drug and gene delivery as well as tissue engineering applications is summarized in the present review.

In silicon spintronics, the unique qualities of ferromagnetic materials are combined with those of silicon, aiming at creating an alternative, energy-efficient information technology in which digital data are represented by the orientation of the electron spin. Here we review the cornerstones of silicon spintronics, namely the creation, detection and manipulation of spin polarization in silicon. Ferromagnetic tunnel contacts are the key elements and provide a robust and viable approach to induce and probe spins in silicon, at room temperature. We describe the basic physics of spin tunneling into silicon, the spin-transport devices, the materials aspects and engineering of the magnetic tunnel contacts, and discuss important quantities such as the magnitude of the spin accumulation and the spin lifetime in the silicon. We highlight key experimental achievements and recent progress in the development of a spin-based information technology.

Syntheses of cyanines: a review Mallika Panigrahi , Sukalyan Dash , Sabita Patel , Bijay K. Mishra a,* Centre of Studies in Surface Science and Technology, School of Chemistry, Sambalpur University, Jyoti Vihar, Burla 768 019, India Department of Chemistry, Veer Surendra Sai University of Technology, Burla 768 018, India Department of Chemistry, National Institute of Technology, Rourkela 769 008, India

The preparation of Pd-nanoparticles embedded into the polymer matrix of poly(1,4-phenylene sulfide) via the thermolysis of palladium acetate is described.

A novel synthetic route to spirocyclic thiazolidinediones is reported by utilizing ring-closing metathesis (RCM). A selective cross metathesis (CM) of N-allyl azaspiro derivatives with different olefins has been demonstrated to prepare substituted azaspiro-[4.4]nonenediones. The X-ray crystal structure of a spirocyclic thiazolidinedione dimer is described, which has been prepared in two steps from thiazolidinedione using a one-pot sequential ring-closing and self metathesis. Cross metathesis proceeds smoothly with both electron rich and poor olefins. The symmetrical bis-thiazolidinedione spirocyclic system can be used as CM coupling partner with olefins. One-pot sequential RCM-CM has been developed for the synthesis of substituted spirocyclic compounds. The methodology allows a quick access to thia-azaspiro-[4.4]nonene and -[4.5]decene-dione ring systems from readily available starting materials which are not otherwise accessible.

Iron can catalyze head-to-head dimerization of terminal aryl alkynes to give the corresponding (E) selective conjugated enynes in high yields. A variety of substituted aryl acetylenes underwent smooth dimerization using catalytic FeCl3 and DMEDA in the presence of KOtBu.

Review: overview of the medicinal chemistry of carboranes emphasizing the use of nanoparticles, dendrimers, porphyrins, and carbohydrates as boron carriers; 80 refs.

The present new three-component reactions of lithiated alkoxyallene (I) and (XIX) with nitriles and carboxylic acids provide highly functionalized -alkoxy--ketoenamides (IV) and (X) which are further cyclized into different pyridine derivatives.

The oxidation of N-alkyl substituted styrylpyridinium bromides in both KMnO4 and cetyltrimethylammonium permanganate (CTAP) results in the formation of corresponding substituted benzaldehydes. The oxidation in aqueous medium is catalyzed by acid whereas in chloroform medium the reaction proceeds at neutral condition. However, the reaction proceeds through the same mechanism in both the media. The faster rate of oxidation in aqueous medium by KMnO4 than that in chloroform medium by CTAP has been rationalized through hydrophobic effect. The overall rate equation can be represented as rate = k[Substrate]1.5[Oxidant]−0.75 in aqueous medium and rate = k[Substrate]0.5[Oxidant]−1 in chloroform medium. From the substituent effect a transition state with low electron density at the olefinic carbon has been proposed.

The standard molar Gibbs energy of formation of BaMoO 4 (s) has been determined by measuring e.m.f. of the cell: Pt/BaMoO 3 (s)+BaMoO 4 (s))/CSZ/air ( p (O 2 )=21.21 kPa)/Pt where CSZ represents 15 mol% CaO stabilized zirconia. E.m.f. measurements were carried out in the temperature range 1091 to 1309 K and its dependence on temperature could be represented by: E (V)±0.001=1.482−3.600×10 −4 T (K). Using the Gibbs energy data on BaMoO 3 (s) from our previous study along with the above e.m.f. data, the Δ f G m o ( T ) for BaMoO 4 (s) was calculated to be: Δ f G o m ( BaMoO 4 , s , T)( kJ mol −1 )±4.7=−1542.0+0.3552T( K ) Δ f H m o (298.15 K) is calculated by the second-law method using the relevant heat capacity data and the variation of Δ f G m o (BaMoO 4 , s, T ) with temperature and the value is −(1557.5±3.6) kJ mol −1 . The third-law values of Δ f H m o (298.15 K) at each experimental temperature were also calculated from free enthalpy functions −{( G o ( T )− H o (298.15 K))/ T } reported in the literature. The mean Δ f H m o (298.15 K) value by this method is −(1536.8±5.2) kJ mol −1 .

The standard molar Gibbs energies of formation of the ternary oxide compounds; LaCoO3(s), La4Co3O10(s) and La2CoO4(s) in the La-Co-O system have been determined by a solid oxide galvanic cell method using 15 mole% calcia stabilized zirconia as the solid electrolyte. The corresponding expressions for the ΔfGm°(T) are given as: Δ f G m °(LaCoO 3 , s, T) (kJ mol −1 ) (±0.6)=−1234.2+0.272T ( K ) (1002 K ≤T≤1204 K ), Δ f G m °(La 4 Co 3 O 10 , s, T) (kJ mol −1 ) (±3.2)=−4663.8+0.969T (K) (1009 K≤T≤1238 K) and Δ f G m °(La 2 CoO 4 , s, T) (kJ mol −1 )(±1.1)=−2017.1+0.347T (K) (1004 K≤T≤1171 K).

Gibbs energies of formation of UPd 4 (s) have been determined by measuring the equilibrium CO(g) pressures over a UO 2 (s)+C(s)+U 0.15 Pd 0.85 (s)+UPd 4 (s) mixture in the temperature range 1202 to 1306 K and are represented as: Δ f G m o ( UPd 4 , s , T)±4.5 ( kJ mol −1 )=−528.1+0.1223T ( K ) (1202≤T ( K )≤1306).

Enthalpy increment measurements on UMoO6(s) have been carried out using a high-temperature Calvet micro-calorimeter in the temperature range 299 to 1000 K. The enthalpy increments were least squares analyzed using Shomate’s method. The complete thermodynamic information for UMoO6(s) has been computed. The enthalpy increment expression for UMoO6(s) as a function of temperature is given by H o (T)−H o (298.15 K )( J mol −1 )=−53928.8+158.65T( K )+21.443×10 −3 T 2 ( K )+14.077×10 5 /T( K ).

Ternary oxides CeTe2O6(s), La2TeO6(s), Nd2TeO6(s), Dy2TeO6(s) and Y2TeO6(s) have been prepared by solid-state reaction technique and characterized by X-ray powder diffraction method. The standard molar Gibbs energy of formation of these compounds have been determined by measuring TeO2(g) over required biphasic equilibrium mixture using a transpiration technique. The standard molar Gibbs energy of formation of these compounds were calculated from the measured TeO2(g) pressures and are given as: { Δ f G ° m ( CeT e 2 O 6 , s , T ) ± 9 } /kJ mo l − 1 = − 1683.0 + 0.4944 ( T /K ) ( 922 ≤ T /K ≤ 1074 ) , { Δ f G ° m ( L a 2 Te O 6 , s , T ) ± 8 } /kJ mo l − 1 = − 2308.6 + 0.5776 ( T /K ) ( 993 ≤ T /K ≤ 1158 ) , { Δ f G ° m ( N d 2 Te O 6 , s , T ) ± 7 } /kJ mo l − 1 = − 2309.1 + 0.5802 ( T /K ) ( 983 ≤ T /K ≤ 1213 ) , { Δ f G ° m ( D y 2 Te O 6 , s , T ) ± 6 } /kJ mo l − 1 = − 2343.7 + 0.5852 ( T /K ) ( 944 ≤ T /K ≤ 1089 ) , { Δ f G ° m ( Y 2 Te O 6 , s , T ) ± 7 } /kJ mo l − 1 = − 2391.2 + 0.5694 ( T /K ) ( 1017 ≤ T /K ≤ 1102 ) . The Gibbs energies of formation of La2TeO6(s), Dy2TeO6(s) and Y2TeO6(s) have been reported for the first time.

Enthalpy increment measurements on Th(MoO 4 ) 2 (s) and Tl 2 MoO 4 (s) have been carried out using a high temperature Calvet micro-calorimeter. The enthalpy increments for Th(MoO 4 ) 2 (s) were least-squares analyzed using Shomate’s method. The constraints used are H o ( T )− H o (298.15 K) is zero at 298.15 K and C o p,m (298.15 K) equal 211.1 J K −1 mol −1 . The resulting expressions is given below: H o (T)−H o (298.15 K ) ( J mol −1 )=−66782+193.73 T ( K )+53.245×10 −3 T 2 ( K )+12.785×10 5 /T ( K ) ( Th(MoO 4 ) 2 (s) , 299≤T ( K )≤1000) Thallium molybdate shows two phase changes in the experimental temperature range 299–800.1 K. Thus, H o ( T )− H o (298.15 K) data for Tl 2 MoO 4 (s) were analyzed in the temperature range 400.3–669.9 (single phase) using origin program version 5 and the constraint used is H o ( T )− H o (298.15 K)=0. The corresponding expression is given as follows: H o (T)−H o (298.15 K ) ( J mol −1 )=−30169+95.99 T ( K )+54.060×10 −3 T 2 ( K ) (Tl 2 MoO 4 (s) , 400.3≤T ( K )≤699.9) The complete thermodynamic functions for Th(MoO 4 ) 2 (s) and Tl 2 MoO 4 (s) have been computed for the first time.

A three-component reaction with lithiated alkoxyallenes, nitriles, and perfluorinated carboxylic acids as precursors led to a series of perfluoroalkyl- or perfluoroaryl-substituted 4-hydroxypyridine derivatives. These compounds were converted into 4-pyridyl nonaflates which can be employed as versatile building blocks for the synthesis of π-conjugated compounds with use of palladium-catalyzed couplings. Suzuki reactions at C-4 and C-3 of the pyridine ring proceeded with moderate to high yields. In addition, Suzuki−Miyaura, Stille, or Buchwald−Hartwig coupling reactions have also been studied and afforded the corresponding highly substituted pyridine derivatives. Starting from an arylated propargylic ether the three-component reaction led to a pentasubstituted 4-hydroxypyridine derivative that could also be employed in palladium-catalyzed processes at C-4 and at C-3 of the pyridine core. With this simple approach the sterically highly crowded 3,4,5-triphenyl-substituted pyridine derivative 37a could be pre...

A simple Diels–Alder route leading to methyl 2,3,4-trihalo-5-hydroxybenzoates via thermal Grob-type rearrangement of easily accessible 1,4,5,6-tetrahalo-7,7-dimethoxybicyclo[2.2.1]hept-5-en-2-one with concomitant methyl halide elimination is described.

[reaction: see text] Alpha-diketones are efficiently reduced with indium metal in methanol-water in the presence of NH(4)Cl, LiCl, or NaCl to give regio- and diastereoselectively the corresponding acyloins in good to excellent yield. The cleavage of the acyloins under Pb(OAc)(4)/MeOH-PhH condition provides a convenient and regioselective access to highly functionalized cyclopentane carboxaldehydes, potential building blocks in organic syntheses.

The tricyclic alpha-keto hemiacetals 3a,b and 8a-d obtained from ruthenium-catalyzed oxidation of tetrahalonorbornyl derivatives possessing a pendant hydroxymethyl group were cleaved using Pb(OAc)(4) or alkaline H(2)O(2) to give gamma-lactone-fused cyclopentane derivatives 5a,b and 9a-d. The alpha-keto hemiacetal 3b has also been elaborated to spiroepoxide derivative 25. The stable hydrate 4 formed from ruthenium-catalyzed oxidation of acrolein adduct 10 furnished an intramolecular hemiacetal 11 upon cleavage with Pb(OAc)(4). The alpha-halo ester moiety in 5a was transformed smoothly in a highly regio- and stereoselective manner to alpha-hydroxy esters through a lactone-assisted intermediate to furnish 18.

Solid state reactions of SrUO4 and TeO2 in 1:1 and 1:2 molar ratio led to the formation of two new quaternary compounds SrUTeO6 and SrUTe2O8. The compounds were characterised by X-ray and thermal methods. X-ray powder diffraction data of both the compounds were indexed on the monoclinic system. The standard Gibbs free energy of formation (ΔfG°, T) data of SrUTeO6(s) and SrUTe2O8(s) were obtained by the vapour pressure measurement of TeO2(g) over these systems by employing the Knudsen effusion mass loss (KEML) technique and could be represented by the relation: Δ f G° SrUTeO 6 (s)=(−2180.7+0.4263 T (K))±30 kJ mol −1 [1080–1162 K] Δ f G° SrUTe 2 O 8 (s)=(−2502.6+0.5816 T (K))±30 kJ mol −1 [955–1041 K]

Some monomeric and dimeric surfactants with functional head groups have been synthesized from di- and triethanolamine synthons. The treatment of alkyl bromide with triethanolamine resulted in simultaneous N-alkylation and O-alkylation products. However, with diethanolamine, N-alkylated products were obtained, which were further used to synthesize various double-tailed surfactants and gemini surfactants.