Herein, we discuss how, why, and when cascade complexation reactions produce stable, mononuclear, luminescent ternary complexes, by considering the binding of hexafluoroacetylacetonate anions (hfac(-) ) and neutral, semi-rigid, tridentate 2,6-bis(benzimidazol-2-yl)pyridine ligands (Lk) to trivalent lanthanide atoms (Ln(III) ). The solid-state structures of [Ln(Lk)(hfac)(3) ] (Ln=La, Eu, Lu) showed that [Ln(hfac)(3) ...

Bacillus cereus sphingomyelinase (Bc-SMase) belongs to the Mg(2+)-dependent neutral sphingomyelinase (nSMase) which hydrolyzes sphingomyelin (SM) to produce phosphocholine and ceramide, and acts as an extracellular hemolysin. Bc-SMase has two metal ion-binding sites in a long horizontal cleft across the molecule, with one Mg(2+) in the central region of the cleft ...

In this study, the aim was to examine bioethanol production of wheat straw residues using an alternative chemical, sodium borohydrate (NaBH(4)) in chemical pretreatment step. The obtained results showed that sodium hydroxide (NaOH) and NaBH(4) treated straw resulted in 87.8% and 83.3% glucan conversion in enzymatic hydrolysis, but hydrogen peroxide ...

Cockayne syndrome protein A is one of the main components in mammalian transcription coupled repair. Here, the overproduction, purification and crystallization of human Cockayne syndrome protein A in complex with its interacting partner DNA damage binding protein 1 are reported. The complex was coproduced in insect cells, copurified and crystallized ...

Hydrolytically stable silanethiol tris(2,6-diisopropylphenoxy)silanethiol (TDST) has been synthesized and reacted with sodium metal. In solid state TDST exhibits π-interactions between the S-H unit and the π-system of the arene, replaced by cation-π interactions in its sodium salts. The interactions are documented by crystal structures and FT-IR spectroscopy.

Dihydrodipicolinate synthase (DHDPS) catalyses the first committed step of the lysine-biosynthesis pathway in bacteria, plants and some fungi. This study describes the cloning, expression, purification and crystallization of DHDPS from the grapevine Vitis vinifera (Vv-DHDPS). Following in-drop cleavage of the hexahistidine tag, cocrystals of Vv-DHDPS with the substrate pyruvate were grown ...

Amorphous nickel powder (Ni(0)) was utilised as a catalyst under mild, aqueous, basic conditions for enhancing the sodium borohydride-mediated reduction of C-N multiple bonds such as oximes, imines, hydrazones and nitriles to produce the corresponding amines in good to excellent yields.

Kinetic and computational studies on the amidation of esters with mixtures of formamide and sodium methoxide are described. Rate studies are consistent with a fast deprotonation of formamide followed by two reversible acyl transfers affected by solvent participation. MP2 calculations suggest that the first acyl transfer between the ester and ...

The treatment of triaminoguanidinium chloride with two equivalents of sodium nitrite under acidic conditions, followed by the cyclization with stoichiometric amounts of either sodium hydroxide solution or solid sodium carbonate yielded 1-amino-5-azidotetrazole (1), 5-azido-1-diazidocarbamoyltetrazole (2), and 1-(aminoazidocarbamoyl)-5-azidotetrazole (3). The three novel compounds could be isolated by short-column liquid chromatography by ...

A robust palladium NHC complex was synthesized and exhibits exceptional activity and selectivity as a precatalyst in the amination of aryl chlorides and tolerates a wide range of substrates at low catalyst loadings.

Cyclometallated gold(iii) complexes containing functionalised (2-dimethylaminomethyl)phenyl ligands have been prepared by transmetallation from boroxines to sodium tetrachloroaurate.

The iridium phosphoramidite complex-promoted regio- and enantioselective reaction of allylic carbonates with sodium triisopropylsilanethiolate produced allylic sulfides in 40-77% yields with up to 97 : 3 (branched : linear) and 89% ee, which were readily transformed into chiral thiol in 68% yield with 87% ee or disulfides with two chiral C-S bond centers in ...

Three sodium thiosulfonate salts, NaMeS(2)O(2)·H(2)O, NaPhS(2)O(2) and NaMeC(6)H(4)S(2)O(2) have been prepared by the direct reaction of the sodium sulfinate salts with elemental sulfur, a clean, benign route that produces no by-products. The structures of the phenyl (which crystallised as a hydrate, NaPhS(2)O(2)·1.5H(2)O) and p-tolyl compounds were determined by X-ray crystallography. ...

The difference in reactivity between the activated 2-bromomethyl-1-tosylaziridine and the non-activated 1-benzyl-2-(bromomethyl)aziridine with respect to sodium methoxide was analyzed by means of DFT calculations within the supermolecule approach, taking into account explicit solvent molecules. In addition, the reactivity of epibromohydrin with regard to sodium methoxide was assessed as well. The ...

A series of new sodium and mixed sodium/manganese clusters have been formed using p-tert-butylcalix[8]arene as a support. In all cases the calixarene adopts the pleated-loop conformation, and the resulting complexes show interesting self-assembly properties depending on the ligated solvent molecules around individual cluster cores.

A palladium-catalyzed direct desulfitative C-arylation of a benzo[d]oxazole C-H bond with arene sulfonyl chlorides is described. The procedure tolerates halo, cyano, nitro, trifluoromethyl, acetyl and acetylamino groups on the phenyl ring of sulfonyl chlorides, providing the arylation products in moderate to good yields. It represents a practical and attractive alternative ...

This paper examines vanadium chloride solutions as electrolytes for an all-vanadium redox flow battery. The chloride solutions were capable of dissolving more than 2.3 M vanadium at varied valence states and remained stable at 0-50 °C. The improved stability appeared due to the formation of a vanadium dinuclear [V(2)O(3)·4H(2)O](4+) or ...

A series of sodium and aluminum atrane complexes of Na(3)L(THF)(5) (1), [AlLMe][Na(4)L(THF)(6)] (2), AlL(THF) (3), AlNaLMe(THF)(2) (4), and AlNaLOBn(THF)(2) (5), wherein L = tris(2-oxy-4,6-di-tert-butyl-benzyl)amine, were synthesized and characterized by NMR, X-ray crystallography, and elemental analysis. The trinuclear sodium atrane complex of Na(3)L(THF)(5) (1) is labile at room temperature; however, the ...

Valuable information on the active sites of molybdenum enzymes has been provided from both Mo(V) electron paramagnetic resonance (EPR) spectroscopy and X-ray absorption spectroscopy (XAS). One of three major categories of Mo(V) EPR signals from the molybdenum enzyme sulfite oxidase is the low-pH signal, which forms in the presence of ...

Evidence for the formation of a unique, six-coordinate cobalamin(ii) complex with the anion-radical SO(2)(-) during the reduction of aquacobalamin(iii) by sodium dithionite, was obtained from spectrophotometric and EPR measurements. The pK(a) value of the weakly coordinated dimethylbenzimidazole group was found to be 4.8 ± 0.1 at 25 °C.

After more than a decade of intense research on NaAlH(4) doped with transition metals as hydrogen storage material, the actual mechanism of the decomposition and rehydrogenation reaction is still unclear. Early on, monomeric AlH(3) was named as a possible transport shuttle for aluminium, but never observed experimentally. Here we report ...

The toxicity of sodium benzoate to trypsin was investigated by fluorescence spectroscopy, synchronous fluorescence spectroscopy, UV-visible absorption spectroscopy and circular dichroism (CD) spectroscopy under mimic physiological conditions. Sodium benzoate could unfold trypsin by decreasing the β-sheet structure, which leads to more exposure of internal amino acid groups and the obvious ...

4-Phenyl-1H-1,5-benzodiazepin-2(3H)-one reacts in the pres-ence of a concentrated aqueous solution of sodium hydroxide and a quaternary ammonium salt (as catalyst) in benzene (phase transfer catalysis) with propargyl bromide, affording the title benzodiazepine derivative, C(18)H(14)N(2)O. In the mol-ecule, the mean plane of the propargyl substituent is almost perpendicular with that of ...

A ferrocene functionalised redox-active [3]rotaxane which contains two interlocked anion recognition sites has been prepared by chloride anion templation. With chloride two equivalents of anion are bound, one in each of the interlocked cavities, while sulfate forms a 1 : 1 stoichimetric sandwich type complex; the rotaxane can also electrochemically sense the ...

The asymmetric unit of the title compound, Na(+)·C(6)H(10)NS(2) (-)·2H(2)O, is composed of a sodium cation, a piperidine-dithio-carbamate anion which exhibits positional disorder, and two lattice water mol-ecules. The atoms of the piperidine ring are divided over two sites with occupancy factors of 0.554 (6) and 0.446 (6). In the crystal, the sodium ...

Differential scanning calorimetry (DSC), circular dichroism (CD), difference spectroscopy (UV-vis), Raman spectroscopy, and small-angle X-ray scattering (SAXS) measurements have been performed in the present work to provide a quantitatively comprehensive physicochemical description of the complexation between bovine fibrinogen and the sodium perfluorooctanoate, sodium octanoate, and sodium dodecanoate in glycine buffer ...

The title compound, Na(+)·C(7)H(7)O(2)S(-)·4H(2)O, is the hydrate of the sodium salt of para-toluene-sulfinic acid. The mol-ecular geometry around the sulfur atom is tetra-hedral with X-S-Y angles spanning a range of 102.23 (6)-110.04 (6)°. In the crystal, the water mol-ecules connect the sodium cations into chains along the b axis via O-H⋯O hydrogen ...

We report on the time evolution of the sodium tetrachloroaurate (NaAuCl(4)) chemical properties as a function of soft X-ray exposure in a dried sample on a silicon surface using X-ray photoelectron spectroscopy (XPS). Our investigations provide mechanistic insight into the photoreduction kinetics from Au(III) to Au(I) and then Au(I) to ...

One pot asymmetrical double allylations of sodium sulfide catalyzed by an iridium complex along with a combination of caesium fluoride and water in dichloromethane have been realized and the double allylation products with two C-S bond chiral centers were obtained in 67-99% yields with b/l 81/19-99/1, dr 85/15-99/1, and 96-99% ...

{Mo(132)} Keplerate anion reacts with tellurites to give a soluble precursor to produce in hydrothermal conditions single-phase M1 MoVTeO light-alkanes oxidation catalyst. Characterization of this Te-containing intermediate by single-crystal X-ray diffraction, (125)Te NMR, UV-visible and redox titration reveals a molybdotellurite anion as a crown-capped Keggin derivative.

Crystalline complexes of d-ribose, d-ribono-1,4-lactone and methyl β-d-ribopyranoside with sodium halides were synthesized and some of their crystal structures determined. Crystal structures of two lactone complexes and a methyl β-d-ribopyranoside reveal the mode of the salt binding and the intricate interplay of cation coordination and hydrogen bonding in these complexes. ...

Ternary Gd(5-x)Zr(x)Si(4) silicides were synthesized by arc melting of the constituent elements and subsequent heat treatments. The Gd(5-x)Zr(x)Si(4) phases adopt the orthorhombic Gd(5)Si(4)-type (space group Pnma) structure for x≤ 0.25 and the tetragonal Zr(5)Si(4)-type (space group P4(1)2(1)2) structure for x≥ 1.0, respectively. The samples with intermediate compositions contain two phases. ...

Trickle-bed air biofilters (TBABs) are suitable for treatment of hydrophilic volatile organic compounds, but they pose a challenge for hydrophobic compounds. Three laboratory-scale TBABs were used for the treatment of an airstream contaminated with different ratios of n-hexane and benzene mixtures. The ratios studied were 1:1, 2:1, and 1:3 n-hexane:benzene ...

In the course of studies on hybrid antibacterials incorporating 2-aryl-5-nitro-1H-indole moieties as potential bacterial NorA efflux pump inhibitors, the compound 1-[2-(5-nitro-1H-indol-2-yl)phenyl]methylpyridinium chloride (2) was synthesized and structurally characterized. This pyridinium chloride salt crystallized in the monoclinic space group P2(1)/c with the following unit cell dimensions: a 10.274(3) Å, b 13.101(4) ...

Dipalladium(I) and diruthenium(I) compounds bridged by two [{(5,7-dimethyl-1,8-naphthyridin-2-yl)amino}carbonyl]ferrocene (L) ligands have been synthesized. The X-ray structures of [Pd(2)L(2)][BF(4)](2) (1) and [Ru(2)L(2)(CO)(4)][BF(4)](2) (2) reveal dinuclear structures with short metal-metal distances. In both of these structures, naphthyridine bridges the dimetal unit, and the site trans to the metal-metal bond is occupied by ...

Phosphine ligands have been demonstrated to have an effect on reactivity and selectivity in the competitive intramolecular palladium-catalysed Suzuki-Miyaura coupling of dibromo sulfoxide 1a possessing two different hybridised electrophilic carbons. It was found that the bromine bond to the sp(3)-hybridised carbon is selectively replaced in the presence of unhindered phosphines ...

A method for the cross-coupling of alkyl electrophiles with various potassium aryl- and heteroaryltrifluoroborates has been developed. Nearly stoichiometric amounts of organoboron species could be employed to cross-couple a large variety of challenging heteroaryl nucleophiles. Several functional groups were tolerated on both the electrophilic and the nucleophilic partners. Chemoselective reactivity ...

Pd(II)-catalyzed β-C(sp(3))-H carbonylation of N-arylamides under CO (1 atm) has been achieved. Following amide-directed C(sp(3))-H cleavage and insertion of CO into the resulting [Pd(II)-C(sp(3))] bond, intramolecular C-N reductive elimination gave the corresponding succinimides, which could be readily converted to 1,4-dicarbonyl compounds. This method was found to be effective with substrates ...

Sodium tert-butoxide mediates the coupling of aryl halides with benzene derivatives without the aid of transition metal catalysts but with a catalytic 1,10-phenanthroline derivative.

The trichlorophenyl-, dichlorodiphenyl-, and chlorotriphenylgermanes undergo Pd-catalyzed cross-couplings with aryl bromides and iodides in the presence of tetrabutylammonium fluoride in toluene with addition of the measured amount of water. One chloride ligand on the Ge center allows efficient activation by fluoride to promote transfer of one, two, or three phenyl ...

A new acetate-bridged dinuclear palladacycle with unsubstituted N-phenylpyrazole [{Pd(phpz)(μ-AcO)}(2)] 1 has been isolated and characterised, including an X-ray diffraction study. A survey of the Cambridge Structural Database (CSD) v. 5.31 looking for analogous dimeric C^N cyclopalladated complexes has been done, exploring the incidence of cisoid/transoid arrangements, the preferred conformation of ...

A cross-coupling reaction of a variety of aryl, heteroaryl, and benzyl chlorides with ArMgX is catalyzed by 2 mol % of a nickel-phosphine complex prepared in situ from an equimolar amount of Ni(CH(3)CN)(2)Cl(2) and ligand (L2) to yield products in excellent yield in THF at room temperature. This new bidentate ...

Tetravinylbenzene 4 was prepared in nearly quantitative yield from commercially available tetrabromobenzene; the improved, one-step procedure now employs Suzuki-Miyaura cross-coupling conditions. Intermolecular cyclopropanation of 4 with dibromocarbene gave a series of gem-dibromide adducts. Intramolecular cyclopropanation of monoadduct 5, putatively by its methyllithium-generated cyclopropylidene(oid), produced compound 11, which features a highly ...

Mechanistic studies revealed ruthenium-catalyzed direct arylations to proceed through reversible C-H bond activation and subsequent rate-limiting oxidative addition with aryl halides, which led to the development of widely applicable well-defined ruthenium(II) carboxylate catalysts.

Dihydrobenzisoxazoles are readily prepared in good yields by the [3 + 2] cycloaddition of oxaziridines and arynes. The reaction involves an unusual cleavage of the C-O bond of the oxaziridine and tolerates a variety of substituents on the oxaziridine and the o-(trimethylsilyl)aryl triflate to form aryl-, heteroaryl-, alkyl-, and naphthyl-substituted ...

The reaction mechanism of Pd(0)-catalyzed methylacetylene bisselenation reaction is investigated by using the density functional method. The overall reaction mechanism involves the oxidative addition, insertion, and reductive elimination steps. The regioselectivity has been investigated for the methylacetylene insertion into Pd--Se bond of both cis and trans palladium complexes. It is ...

The reduction of diazonium salts has recently been proposed as a robust covalent modification scheme for graphene surfaces. While preliminary studies have provided indirect evidence that this strategy decorates graphene with aryl moieties, the molecular ordering and conformation of the resulting adlayer have not been directly measured. In this Article, ...

A mild Negishi cross-coupling of 2-heterocyclic organozinc reagents and aryl chlorides is described. The use of Pd(2)(dba)(3) and X-Phos as a ligand provides high yields for many examples. An efficient method to generate the organozinc reagents at room temperature is also demonstrated.

Ligand effects in bimetallic high oxidation state systems containing a X-Pd-Pd-Y framework have been explored with density functional theory (DFT). The ligand X has a strong effect on the dissociation reaction of Y to form [X-Pd-Pd](+) + Y(-). In the model system examined where Y is a weak σ-donor ligand ...

A simple, highly reproducible protocol for the hydrogenation of alkenes and alkynes and for the hydrogenolysis of O-benzyl ethers has been developed. The method features the in situ preparation of an active Pd(0)/C catalyst from Pd(OAc)(2) and charcoal, in methanol. The mild reaction conditions (25°C) and low catalyst loading required ...