Showing papers in "Applied Organometallic Chemistry in 2010"
TL;DR: In this article, it was shown that the reaction does not involve hydroxyl radicals as main oxidizing species and apparently proceeds with the participation of osmyl species, ‘OsO’.
Abstract: Trinuclear carbonyl hydride cluster, Os3(CO)10(µ-H)2, catalyzes oxidation of cyclooctane to cyclooctyl hydroperoxide by hydrogen peroxide in acetonitrile solution. The hydroperoxide partly decomposes in the course of the reaction to afford cyclooctanone and cyclooctanol. Selectivity parameters obtained in oxidations of various linear and branched alkanes as well as kinetic features of the reaction indicated that the alkane oxidation occurs with the participation of hydroxyl radicals. A similar mechanism operates in transformation of benzene into phenol and styrene into benzaldehyde. The system also oxidizes 1-phenylethanol to acetophenone. The kinetic study led to a conclusion that oxidation of alcohols does not involve hydroxyl radicals as main oxidizing species and apparently proceeds with the participation of osmyl species, ‘OsO’. Copyright © 2010 John Wiley & Sons, Ltd.
136 citations
TL;DR: In this paper, the authors introduce an advance in iron-catalyzed hydrosilylation of olefins, aldehydes, ketones and amides.
Abstract: Iron-catalyzed hydrosilylation is one of the most popular reduction reactions owing to the high natural abundance, low cost and low toxicity of iron and silicon. This paper introduces an advance in iron-catalyzed hydrosilylation of olefins, aldehydes, ketones and amides. Some reactions exhibit good functional group tolerance and chemoselectivities. These protocols provide economical, sustainable and practical tools for organic chemists. Copyright © 2010 John Wiley & Sons, Ltd.
133 citations
TL;DR: In this article, the authors synthesize symmetrically substituted N-heterocyclic carbene (NHC) precursors from the reaction of 1H-imidazole (1a), 4,5-dichloro-1,3-bis(4-cyanobenzyl)imidazi-2-ylidene) with benzyl bromide (2), and NHC-silver complexes with NHC pre-precursor.
Abstract: From the reaction of 1H-imidazole (1a), 4,5-dichloro-1H-imidazole (1b) and 1H-benzimidazole (1c) with p-cyanobenzyl bromide (2), symmetrically substituted N-heterocyclic carbene (NHC) [(3a–c)] precursors, 1-methylimidazole (5a), 4,5-dichloro-1-methylimidazole (5b) and 1-methylbenzimidazole (5c) with benzyl bromide (6), non-symmetrically substituted N-heterocyclic carbene (NHC) [(7a–c)] precursors were synthesized. These NHCprecursors were then reacted with silver(I) acetate to yield the NHC-silver complexes [1,3-bis(4-cyanobenzyl)imidazole-2-ylidene] silver(I) acetate (4a), [4,5-dichloro-1,3-bis(4-cyanobenzyl)imidazole-2-ylidene] silver(I) acetate (4b), [1,3-bis(4-cyanobenzyl)benzimidazole-2-ylidene] silver(I) acetate (4c), (1-methyl-3-benzylimidazole-2-ylidene) silver(I) acetate (8a), (4,5-dichloro-1-methyl-3-benzylimidazole-2-ylidene) silver(I) acetate (8b) and (1-methyl-3-benzylbenzimidazole-2-ylidene) silver(I) acetate (8c) respectively. The four NHC-precursors 3a–c, 7c and four NHC–silver complexes 4a–c and 8c were characterized by single crystal X-ray diffraction. The preliminary antibacterial activity of all the compounds was studied against Gram-negative bacteria Escherichia coli, and Gram-positive bacteria Staphylococcus aureus using the qualitative Kirby-Bauer disc-diffusion method. All NHC–silver complexes exhibited medium to high antibacterial activity with areas of clearance ranging from 4 to 12 mm at the highest amount used, while the NHC-precursors showed significantly lower activity. In addition, all NHC–silver complexes underwent preliminary cytotoxicity tests on the human renal-cancer cell line Caki-1 and showed medium to high cytotoxicity with IC50 values ranging from 53 ( ± 8) to 3.2 ( ± 0.6) µM. Copyright © 2010 John Wiley & Sons, Ltd.
82 citations
TL;DR: In this article, the effect of constituents on structure, flow, and thermal properties of nanoscale ionic materials (NIMs) is discussed, and a new class of nanohybrids consisting of a nanometer-sized core, a charged corona covalently attached to the core, and an oppositely charged canopy is introduced.
Abstract: In this article we discuss the effect of constituents on structure, flow, and thermal properties of nanoscale ionic materials (NIMs). NIMs are a new class of nanohybrids consisting of a nanometer-sized core, a charged corona covalently attached to the core, and an oppositely charged canopy. The hybrid nature of NIMs allows for their properties to be engineered by selectively varying their components. The unique properties associated with these systems can help overcome some of the issues facing the implementation of nanohybrids to various commercial applications, including carbon dioxide capture, water desalinization and as lubricants. Copyright © 2010 John Wiley & Sons, Ltd.
79 citations
TL;DR: In this paper, the first heptacyclic laddersiloxanes and ladder polysilsesquioxane were synthesized and the spectral and thermal properties of these new compounds were investigated.
Abstract: As a continuation of our previous studies on thermostable materials, heptacyclic laddersiloxanes and ladder polysilsesquioxane were synthesized. The first heptacyclic laddersiloxanes were obtained by chlorination of pentacyclic laddersiloxanes prepared using our stereocontrolled synthesis procedure; thereafter, the heptacyclic laddersiloxanes were made to react with disiloxanediol. Ladder polysilsesquioxane was obtained from cis–trans–cis-tetrabromotetramethylcyclotetrasiloxane by spontaneous hydrolysis and dehydration. The spectral and thermal properties of these new compounds were investigated. It was observed that the thermal stability of these compounds increases with the ring number. Copyright © 2010 John Wiley & Sons, Ltd.
55 citations
TL;DR: In this article, arylsilanes and alkylfluorides are efficiently catalyzed by disilyl cation 1 and are found to give arenes with mostly rearranged alkyl substituents.
Abstract: CC coupling reactions between arylsilanes and alkylfluorides are efficiently catalyzed by disilyl cation 1. Primary as well as secondary alkylfluorides were quantitatively coupled with arylsilanes; however, in the case of tertiary fluorides, the hydrodefluorination reaction predominated. Primary alkylfluorides were found to give arenes with mostly rearranged alkyl substituents. In all cases subsequent Friedel–Crafts-type chemistry occurred. Copyright © 2010 John Wiley & Sons, Ltd.
53 citations
TL;DR: In this article, the authors introduce an advance on copper-catalyzed/mediated aromatic CH functionalization, which includes aromatic ring CH bond functionalization and heteroaromatic CH bondfunctionalization forming new carbon-carbon or carbon-heteroatom bonds.
Abstract: The CH functionalization strategy has received substantial attention because of its economic, sustainable and environmentally benign features. Most reports are on palladium, rhodium or ruthenium catalysis, and reports on copper catalysis are relatively fewer. Recently, many reports on copper-catalyzed/mediated CH functionalization have been published. Copper salts bear properties of cheapness and relatively low toxicity. This review introduces an advance on copper-catalyzed/mediated aromatic CH functionalization. The content includes aromatic ring CH bond functionalization and heteroaromatic CH bond functionalization forming new carbon–carbon or carbon–heteroatom bonds. Copyright © 2010 John Wiley & Sons, Ltd.
52 citations
TL;DR: In this paper, the chiral ligands N,N′-bis-[(1R)-1-ethyl-2-O-(diphenylphosphinite)ethyl]ethanediamide, 1, and the corresponding ruthenium complexes 3 and 4 were prepared and their structures were elucidated by a combination of multinuclear NMR spectroscopy, IR and elemental analysis.
Abstract: The new chiral ligands N,N′-bis-[(1R)-1-ethyl-2-O-(diphenylphosphinite)ethyl]ethanediamide, 1, and N,N′-bis-[(1S)-1-isobutyl-2-O-(diphenylphosphinite)ethyl]ethanediamide, 2, and the corresponding ruthenium complexes 3 and 4 were prepared and their structures were elucidated by a combination of multinuclear NMR spectroscopy, IR spectroscopy and elemental analysis. Following activation by NaOH, these chiral ruthenium complexes serve as catalyst precursors for the asymmetric transfer hydrogenation of acetophenone derivatives in iPrOH. The complexes 3 and 4 showed high catalytic activity but low selectivity in asymmetric transfer hydrogenation reactions. Copyright © 2009 John Wiley & Sons, Ltd.
48 citations
TL;DR: In this article, a hybrid consolidant based on tetraethoxysilane (TEOS) and fillers such as colloidal silica (200 nm in diameter) and hydroxy-terminated polydimethylsiloxane (PDMS-OH) was proposed.
Abstract: The consolidation of materials concept, which consists of introducing a chemical substance (consolidant) into degraded stone, has been applied to architectural conservation. Silicon compounds such as tetraethoxysilane (TEOS) are frequently used as a base for commercial consolidant formulations due to their ability to form a siloxane polymer such as SiO2. However, the silica xerogels deposited into the stone show poor performance and the gels obtained are non-porous and tend to crack during the drying stage. In order to avoid the fractures and to improve gel properties, we propose the synthesis of a hybrid consolidant based on TEOS and fillers such as colloidal silica (200 nm in diameter) and hydroxy-terminated polydimethylsiloxane (PDMS-OH). Both additives enhance gel properties such as porosity and elasticity, leading to the formation of non-fractured and permeable gels. Characterization of the hybrid xerogel was carried out by nitrogen adsorption and 29Si MAS-NMR. The properties of the hybrid xerogels were compared with those prepared from a formulation based on TEOS (T-ME) with a composition similar to a commercial product. In order to evaluate the effectiveness of the hybrid consolidant, it was applied to tuff-stone of historical monuments in the city of Guanajuato, Mexico. The tuff-stone was also treated with the formulation T-ME. Both treatments were studied by determining the percentage of consolidant deposited, evaluating changes in porosity and hardness of the treated stone. The applicability of the hybrid consolidant for the decayed tuff-stone is under study. Copyright © 2010 John Wiley & Sons, Ltd.
44 citations
TL;DR: In this article, a series of chiral bis(azolium) salts have been prepared following a synthetic pathway, starting from L-valinol and the modular buildup allows the structural variation of the ligand precursors.
Abstract: The common use of NHC complexes in transition-metal mediated C–C coupling and metathesis reactions in recent decades has established N-heterocyclic carbenes as a new class of ligand for catalysis. The field of asymmetric catalysis with complexes bearing NHC-containing chiral ligands is dominated by mixed carbene/oxazoline or carbene/phosphane chelating ligands. In contrast, applications of complexes with chiral, chelating bis(NHC) ligands are rare. In the present work new chiral iridium(I) bis(NHC) complexes and their application in the asymmetric transfer hydrogenation of ketones are described. A series of chiral bis(azolium) salts have been prepared following a synthetic pathway, starting from L-valinol and the modular buildup allows the structural variation of the ligand precursors. The iridium complexes were formed via a one-pot transmetallation procedure. The prepared complexes were applied as catalysts in the asymmetric transfer hydrogenation of various prochiral ketones, affording the corresponding chiral alcohols in high yields and moderate to good enantioselectivities of up to 68%. The enantioselectivities of the catalysts were strongly affected by the various, terminal N-substituents of the chelating bis(NHC) ligands. The results presented in this work indicate the potential of bis-carbenes as stereodirecting ligands for asymmetric catalysis and are offering a base for further developments. Copyright © 2010 John Wiley & Sons, Ltd.
42 citations
TL;DR: In this article, the tridentate binding of the Schiff base ligand involving azomethine nitrogen, naphthol oxygen and carboxylato oxygen atoms was confirmed by elemental analysis, IR, electronic spectra, conductance measurements, magnetic measurements and powder XRD.
Abstract: Novel zinc(II), copper(II), and cobalt(II) complexes of the Schiff base derived from 2-hydroxy-1-naphthaldehyde and D, L-selenomethionine were synthesized and characterized by elemental analysis, IR, electronic spectra, conductance measurements, magnetic measurements and powder XRD. The analytical data showed the composition of the metal complex to be ML(H2O), where L is the Schiff base ligand and M = Co(II), Cu(II) and Zn(II). IR results confirmed the tridentate binding of the Schiff base ligand involving azomethine nitrogen, naphthol oxygen and carboxylato oxygen atoms. 1H NMR spectral data of lithium salt of the Schiff base ligand [Li(HL)] and ZnL(H2O) agreed with the proposed structures. The conductivity values of complexes between 12.50 and 15.45 S cm2 mol−1 in DMF suggested the presence of non-electrolyte species. The powder XRD studies indicated that Co(II) complex is amorphous, whereas Cu(II) and Zn(II) complexes are crystalline. The results of antibacterial and antifungal screening studies indicated that Li(HL) and its metal complexes are active, but CuL(H2O) is most active among them. Copyright © 2010 John Wiley & Sons, Ltd.
TL;DR: In this article, the feasibility of using phosphite as an alternative source of reducing equivalents was demonstrated, which combines the catalytic activities of hydrogenases, formate and phosphite dehydrogenases in one catalyst.
Abstract: The organometallic compound [Cp*Rh(bpy)(H2O)]2+ is a versatile catalyst for the in situ regeneration of reduced nicotinamides and flavins by catalyzing the electron transfer between the cathode or formate to the oxidized cofactors and prosthetic groups. In the present contribution we demonstrate the feasibility of phosphite as an alternative source of reducing equivalents. Thus, [Cp*Rh(bpy)(H2O)]2+ combines the catalytic activities of hydrogenases, formate and phosphite dehydrogenases in one catalyst. The catalytic properties of this novel regeneration approach are investigated, demonstrating that the general catalytic properties of [Cp*Rh(bpy)(H2O)]2+ are preserved. The principal applicability to promote alcoholdehydrogenase-catalyzed reduction reactions is demonstrated. Copyright © 2010 John Wiley & Sons, Ltd.
TL;DR: In this paper, the benzimidazol-2-ylidene carbene complexes of Ag(I) were prepared by interaction of the corresponding benzimideazolium salt with Ag2O in dichloromethane, and the new complexes were found to be effective antimicrobial activity against a series of bacteria and fungi.
Abstract: Novel benzimidazol-2-ylidene carbene complexes of Ag(I) were prepared by interaction of the corresponding benzimidazolium salt with Ag2O in dichloromethane. Their structures were characterized by elemental analyses, 1H-NMR, 13C-NMR and IR spectroscopy techniques. All compounds studied in this work were screened for their in vitro antimicrobial activities against the standard strains: Enterococcus faecalis (ATCC 29212), Staphylococcus aureus (ATCC 29213), Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853) and the fungi Candida albicans and Candida tropicalis. The new complexes were found to be effective antimicrobial activity against a series of bacteria and fungi. Copyright © 2010 John Wiley & Sons, Ltd.
TL;DR: In this article, a ligand BDPPZ (9a,13a,dihydro-4,5,9,14-tetraaza-benzo[b]triphenylene-11-yl)-phenyl-methanone) and its polypyridyl hetero- and homoleptic Ru(II) metal complexes were synthesized and characterized by elemental analysis, UV-vis, FT-IR, 1H and 13C-NMR spectra (for ligand), molar conductivity measurements and X
Abstract: Based on the a ligand BDPPZ [(9a,13a-dihydro-4,5,9,14-tetraaza-benzo[b]triphenylene-11-yl)-phenyl-methanone] (1) and its polypyridyl hetero- and homoleptic Ru(II) metal complexes, [Ru(bpy)2L](PF6)2 (2), [Ru(phen)2L](PF6)2 (3), [Ru(dafo)2L](PF6)2 (4), [Ru(dcbpy)2L](PF6)2 (5) and [RuL3](PF6)2 (6) (where, L = ligand, bpy = 2,2′-bipyridine, phen = 1,10-phenantroline, dafo = 4,5-diazafluoren-9-one and dcbpy = 3,3′-dicarboxy-2,2′-bipyridine), have been synthesized and characterized by elemental analysis, UV–vis, FT-IR, 1H and 13C-NMR spectra (for ligand), molar conductivity measurements and X-ray powder techniques The electrochemical parameters of the substituted ligand and its polypyridyl hetero- and homoleptic Ru(II) metal complexes are reported by cyclic voltammetry UV–vis spectroscopy is used to compare the differences between the conjugated π systems in this ligand and its Ru(II) metal complexes The polypyridyl hetero- and homoleptic Ru(II) metal complexes also tested as catalysts for the formation of cyclic organic carbonates from carbon dioxide and liquid epoxides which served as both reactant and solvent The results showed that the [Ru(L)3](PF6)2 (6) complex is more efficient than the other Ru(II) complexes for the formation of cyclic organic carbonates from carbon dioxide Copyright © 2010 John Wiley & Sons, Ltd
TL;DR: In this article, an efficient and convenient three-component A3 coupling reaction of aldehyde, amine and alkyne via CH activation with CuI alone as the catalyst in PEG is developed, providing a wide range of propargylamines with yields ranging from moderate to excellent.
Abstract: An efficient and convenient three-component A3 coupling reaction of aldehyde, amine and alkyne via CH activation with CuI alone as the catalyst in PEG is developed, providing a wide range of propargylamines with yields ranging from moderate to excellent. Additionally, the catalyst system was recovered and reused several times without evident loss in activity. Copyright © 2010 John Wiley & Sons, Ltd.
TL;DR: In this paper, a high-energy ball milling process was used to synthesize silicon nanoparticles with a variety of covalently bonded surfaces depending on the nature of the organic liquid used in the milling processes.
Abstract: Silicon nanoparticles are useful materials for optoelectronic devices, solar cells and biological markers. The synthesis of air-stable nanoparticles with tunable optoelectronic properties is highly desirable. The mechanochemical synthesis of silicon nanoparticles via high-energy ball milling produces a variety of covalently bonded surfaces depending on the nature of the organic liquid used in the milling process. The use of the C8 reactants including octanoic acid, 1-octanol, 1-octaldehyde and 1-octene results in passivated surfaces characterized by strong SiC bonds or strong SiO bonds. The surfaces of the nanoparticles were characterized by infrared spectroscopy and nuclear magnetic resonance spectroscopy. The nanoparticles were soluble in common organic solvents and remarkably stable against agglomeration and air oxidation. The luminescence and optical properties of the nanoparticles were very sensitive to the nature of their passivating surface. Copyright © 2009 John Wiley & Sons, Ltd.
TL;DR: The polar phosphinyl carboxamide, 1'-(diphenylphosphino)-1-[N-(2-hydroxyethyl)carbamoyl]-ferrocene [I; Z = null; (1)], reacts readily with H2O2 and elemental S to give the corresponding phosphine oxide I [Z = O (2)] and phosphine sulfide I [S = S (3)], resp., and with Pt(II) and Pd(II)-precursor to afford various bis(phosphine) complexes [
Abstract: The polar phosphinyl carboxamide, 1'-(diphenylphosphino)-1-[N-(2-hydroxyethyl)carbamoyl]ferrocene [I; Z = null; (1)] , reacts readily with H2O2 and elemental S to give the corresponding phosphine oxide I [Z = O (2)] and phosphine sulfide I [Z = S (3)], resp., and with Pt(II) and Pd(II) precursors to afford various bis(phosphine) complexes [MCl2(1-κP)2] (M = trans-Pd, trans-Pt and cis-Pt). The structures of 2 and 3 were detd. by x-ray crystallog. The anticancer activity of the compds. was evaluated in vitro with the complexes showing moderate cytotoxicities towards human ovarian cancer cells. Also, the biol. activity is strongly influenced by the stereochem., with trans-[PtCl2(1-κP)2] being an order of magnitude more active than the corresponding cis isomer. Copyright © 2010 John Wiley and Sons, Ltd.
TL;DR: In this article, it was shown that ethanol can promote the Pd/C-catalyzed reductive homocoupling of aryl iodides and bromides efficiently in the presence of base.
Abstract: Homocoupling reactions of aryl bromides or iodides proceeded smoothly with palladium on carbon (Pd/C) catalyst, ethanol and base in dimethyl sulfoxide (DMSO) to afford exclusively symmetric biaryls in good to excellent yields. Ethanol was first used as a reducing agent in situ to reduce the Pd2+/C species into Pd0/C active species to complete the catalytic redox cycle. It was found that ethanol can promote the Pd/C-catalyzed reductive homocoupling of aryl iodides and bromides efficiently in the presence of base. A reaction mechanism has been put forward and discussed. Copyright © 2010 John Wiley & Sons, Ltd.
TL;DR: In this paper, the authors investigated the activity of [Pd(C6H4CH2 NH2-κ2-C-N)PPh3MOBPPY]OTf complex in the Heck-Mizoroki CC cross-coupling reaction under conventional heating and microwave irradiation conditions.
Abstract: The activity of [Pd(C6H4CH2 NH2-κ2-C-N)PPh3MOBPPY]OTf complex, A (MOBPPY = 4-methoxybenzoylmethylenetriphenyl- phosphoraneylide), was investigated in the Heck–Mizoroki CC cross-coupling reaction under conventional heating and microwave irradiation conditions. The complex is an active and efficient catalyst for the Heck reaction of aryl halides. The yields were excellent using a catalytic amount of [Pd(C6H4CH2 NH2-κ2-C-N)PPh3MOBPPY]OTf complex in N-methyl-2-pyrrolidinone (NMP) at 130 °C and 600 W. In comparison to conventional heating conditions, the reactions under microwave irradiation gave higher yields in shorter reaction times. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd.
TL;DR: In this article, a bi-dentate ligand 4-amino-N′-[(8-hydroxyquinoline-5-yl)methyl] benzenesulfonohydrazide (AHQMBSH) having above both moieties within a single molecular framework was synthesized by the reaction of N-acetamidobenzene sulfonhydrazide with 5-chloromethyl-8-hexoxyquinoline hydrochloride.
Abstract: Looking at the pharmacological importance of 8-hydroxyquinolines and sulfonamides, in the present study, a novel bi-dentate ligand 4-amino-N′-[(8-hydroxyquinoline-5-yl)methyl] benzenesulfonohydrazide (AHQMBSH) having above both moieties within a single molecular framework was synthesized by the reaction of N-acetamidobenzene sulfonohydrazide with 5-chloromethyl-8-hydroxyquinoline hydrochloride. Its metal(II) oxinates were also prepared with Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II) salts. All the above compounds were investigated by physicochemical analyses, thermogravimetric analysis and spectroscopic techniques. Antimicrobial activities for the above prepared compounds were carried out using the agar-plate method against various strains of bacteria (Staphylococcus aureus, Bacillus subtillis, Pseudomonas aerugionsa, Escherichia coli) and fungi (Aspergillus niger and Aspergillus flavous). The results show a significant increase in antimicrobial and antifungal activities of AHQMBSH compared with the parent 8-hydroxyquinoline and sulfonamides. Copyright © 2010 John Wiley & Sons, Ltd.
TL;DR: Li-doped TiO2 nanoparticles were synthesized using the sol-gel process and solid-state sintering, and their potential use as a photocatalyst for degradation under sunlight excitation of different organic model compounds in aqueous solution was investigated in this paper.
Abstract: This work reports on the synthesis of Li-doped TiO2 nanoparticles using the sol–gel process and solid-state sintering, and investigates their potential use as a photocatalyst for degradation under sunlight excitation of different organic model compounds in aqueous solution. The structure of the nanocrystals was examined by X-ray diffraction, UV-vis ground state diffuse reflectance absorption spectra and X-ray photoelectron emission spectroscopy. Results showed that samples prepared by sol–gel process and calcined at 400 °C are composed of a mixture of anatase and rutile phases, in contrast to the one prepared by solid-state sintering, which exhibits an anatase phase with Li being involved in a spinel phase. The photocatalytic degradation of aqueous solutions of different aromatic compounds was successfully achieved under sunlight excitation in presence of Li-doped TiO2 prepared via sol–gel process. It was shown that the calcination temperature and the preparation mode greatly affect the photocatalytic efficiency. Copyright © 2010 John Wiley & Sons, Ltd.
TL;DR: Azobenzene-containing silanol dyes were synthesized and their applicability to dye-sensitized solar cells was investigated in this article, where they showed better effectiveness when compared with conventional carboxy-substituted azobenzenes dyes.
Abstract: Azobenzene-containing silanol dyes were synthesized, and their applicability to dye-sensitized solar cells was investigated. Silanol dyes showed better effectiveness when compared with conventional carboxy-substituted azobenzene dyes. Moreover, silanol dyes showed better durability than carboxyl dyes; ∼90% of silanol dyes remained intact on the TiO2 electrode of the solar cell after being immersed in water for 96 h, whereas in the case of carboxy dyes this figure was less than 20%. Copyright © 2010 John Wiley & Sons, Ltd.
TL;DR: An efficient method for preparation of aryl nitriles using [Pd{C6H2(CH2CH2 NH2)-(OMe)2,3,4} (µ-Br)]2 complex as an efficient catalyst and K4[Fe(CN)6] as a green cyanide source was reported in this paper.
Abstract: An efficient method for preparation of aryl nitriles—using [Pd{C6H2(CH2CH2 NH2)-(OMe)2,3,4} (µ-Br)]2 complex as an efficient catalyst and K4[Fe(CN)6] as a green cyanide source—from aryl bromides, aryl iodides and aryl chlorides under microwave irradiation has been reported. This complex has been demonstrated to be an active and efficient catalyst for this reaction. Using a catalytic amount of this synthesized palladium complex in DMF at 130 °C led to production of the cyanoarenes in excellent yields in short reaction times. Copyright © 2010 John Wiley & Sons, Ltd.
TL;DR: Novel palladium(II)-N-(2-pyridyl)-N′-(5-R-salicylidene) hydrazine triphenylphosphine complexes were synthesized and characterized by UV, IR, 1H NMR and 31P NMR spectral analysis, C, H, N analysis and magnetic susceptibility measurements as discussed by the authors.
Abstract: Novel palladium(II)-N-(2-pyridyl)-N′-(5-R-salicylidene) hydrazine triphenylphosphine complexes were synthesized and characterized by UV, IR, 1H NMR and 31P NMR spectral analysis, C, H, N analysis and magnetic susceptibility measurements. The complexes were effective in the catalytic oxidation of primary and secondary alcohols in presence of N-methyl-morpholine-N-oxide as oxidant. The oxidation reactions were carried out in dichloromethane. A mechanistic study of the above reactions has been proposed. Copyright © 2010 John Wiley & Sons, Ltd.
TL;DR: In this article, a decomposition mechanism was proposed for each complex based on electrospray ionization tandem mass spectrometric results, and the result relates well to that in the literature for SnS, 1.3 eV.
Abstract: Preparation of tin(II) sulfide, semiconductor material, has been accomplished by thermal decomposition of easily prepared organotin dithiocarbamate complexes: [Sn{S2CNEt2}2Ph2] (1), [Sn{S2CNEt2}Ph3] (2), [Sn{S2CNEt2}3Ph] (3) and [Sn{S2CN(C4H8)}2Bu2] (4). Phase-pure tin(II) sulfide has been obtained by pyrolysis of these precursors at 350 °C in N2. Thermogravimetric analysis, X-ray powder diffraction, scanning electron microscopy, X-ray electron probe microanalysis and 119Sn Mossbauer spectroscopy revealed that the complexes decompose in a single and sharp step (1 and 2), or in pseudo-single stage (3 and 4), to produce SnS. We have also measured the bandgap energies of the residues using electronic spectroscopy in the solid state and the result relates well to that in the literature for SnS, 1.3 eV. A decomposition mechanism was also proposed for each complex based on electrospray ionization tandem mass spectrometric results. The synthetic method used in this work might be useful for the preparation of pure SnS on a large scale. Copyright © 2010 John Wiley & Sons, Ltd.
TL;DR: A number of organosilicon precursors for silicon carbide and silicon carbonitride thin-film coatings, such as silanes, carbosilanes, aminosilanes and disilazane, were characterized in terms of their reactivity in a remote microwave plasma chemical vapor deposition process, which was induced using hydrogen as plasma generating gas as discussed by the authors.
Abstract: A number of organosilicon precursors for silicon carbide and silicon carbonitride thin-film coatings, such as silanes, carbosilanes, aminosilanes, and disilazane, respectively, were characterized in terms of their reactivity in a remote microwave plasma chemical vapor deposition process, which was induced using hydrogen as plasma generating gas. The process displayed high selectivity with respect to the activating species and the chemical bonds in the molecular structure of the precursors. In view of very short life times of excited hydrogen plasma species the activation step takes place with an exclusive contribution of ground-state hydrogen atoms. The CH, CC, SiC, SiN, CN and NH bonds present in the molecules of the precursors are non-reactive and only the SiH or SiSi bonds play a key role in the activation step. The reactivity of the precursors was characterized in a quantitative way by the yield of the film growth parameter. The yield parameter expressing the mass of film per unit mass of the precursor fed to the reactor was calculated from the slopes of linear plots of time dependencies of film mass and precursor mass, which were determined for each investigated precursor. The reactivity of the precursors was found to be strongly dependent on the number of the SiH units present in their molecules and those containing two SiH units appeared to be most reactive. Copyright © 2009 John Wiley & Sons, Ltd.
TL;DR: In this article, the authors summarize the results in fuel cell catalyst preparation applying triorganohydroborate chemistry, "reductive particle stabilization" using organoaluminum compounds, and the controlled decomposition of organometallic complexes.
Abstract: During the last few decades organometallic methodologies have generated a number of highly effective electrocatalyst systems based on mono- and bimetallic nanosparticles having controlled size, composition and structure. In this microreview we summarize our results in fuel cell catalyst preparation applying triorganohydroborate chemistry, ‘reductive particle stabilization’ using organoaluminum compounds, and the controlled decomposition of organometallic complexes. The advantages of organometallic catalyst preparation pathways are exemplified with RuPt nanoparticles@C as promising anode catalysts to be used in direct methanol oxidation fuel cells (DMFC) or in polymer electrolyte fuel cells (PEMFC) running with CO-contaminated H2 as the feed. Recent findings with highly efficient PtCo3@C fuel cell catalysts applied for the oxygen reduction reaction (ORR) and with the effect of Se-doping on Ru@C ORR catalysts clearly demonstrate the benefits of organometallic catalyst synthesis. Copyright © 2010 John Wiley & Sons, Ltd.
TL;DR: In this article, three pyridyl functionalized bis(pyrazol-1-yl)methanes were synthesized by the reactions of (2-hydroxyphenyl)bis(Pyrazol 1-yl)-methane with chloromethylpyridine.
Abstract: Three pyridyl functionalized bis(pyrazol-1-yl)methanes, namely 2-[(4-pyridyl)methoxyphenyl] bis(pyrazol-1-yl)methane (L1), 2-[(4-pyridyl)methoxyphenyl]bis(3,5-dimethylpyrazol-1-yl)methane (L2) and 2-[(3-pyridyl)methoxyphenyl]bis(pyrazol-1-yl)methane (L3) have been synthesized by the reactions of (2-hydroxyphenyl)bis(pyrazol-1-yl)methanes with chloromethylpyridine. Treatment of these three ligands with R2SnCl2 (R = Et, n-Bu or Ph) yields a series of symmetric 2:1 adducts of (L)2SnR2Cl2 (L = L1, L2 or L3), which have been confirmed by elemental analysis and NMR spectroscopy. The crystal structures of (L2)2Sn(n-Bu)2Cl2·0.5C6H14 and (L3)2SnEt2Cl2 determined by X-ray crystallography show that the functionalized bis(pyrazol-1-yl)methane acts as a monodentate ligand through the pyridyl nitrogen atom, and the pyrazolyl nitrogen atoms do not coordinate to the tin atom. The cytotoxic activity of these complexes for Hela cells in vitro was tested. Copyright © 2010 John Wiley & Sons, Ltd.
TL;DR: In this paper, mixed sulfur donor ligand complexes of the type bismuth(III) bis(N,N-dialkyldithiocarbamato) alkylenedithiophosphate, [R2NCS2]2BiS2POGO [where R = CH3 and C2H5; G = -CH2-C(C 2H5)2-CH2-, -CH 2 -C(CH3)5) 2-CH3)-CH 3]-and -CH 3)-2-
Abstract: Mixed sulfur donor ligand complexes of the type bismuth(III) bis(N,N-dialkyldithiocarbamato) alkylenedithiophosphate, [R2NCS2]2BiS2POGO [where R = CH3 and C2H5; G = -CH2-C(C2H5)2-CH2-, -CH2-C(CH3)2-CH2-, -CH(CH3)-CH(CH3)- and -C(CH3)2-C(CH3)2-] were synthesized in 1:1 molar ratio of bismuth(III) bis(N,N-dialkyldithiocarbamate) chloride and ammonium alkylenedithiophosphate in refluxing benzene and characterized by melting point, molecular weight determinations, elemental analysis (C, H, N, Bi and S) and spectral [UV, IR,NMR (1H,13C and 31P) and powder X ray diffraction] studies; all these studies were in good agreement with the synthesized complexes. These newly synthesized derivatives are yellow and brown colored solids and are soluble in common organic solvents like benzene, chloroform, dichloromethane and DMF. Based on the physicochemical and spectral studies, a tentative structure of these newly synthesized complexes was assigned and the average particle size of the synthesized complexes determined by powder XRD, showing that nano range polycrystalline particles were formed with a monoclinic crystal system. These complexes were also screened for their antimicrobial activities using the well diffusion method. The free ligands as well as their mixed metal complexes were tested in vitro against four bacterial strains: two Gram-positive, Staphylococcus aureus (ATCC 9144) (G+) and Bacillus subtilis (ATCC 6051), (G+) and two Gram-negative, Escherichia coli (ATCC 9637) (G−) and Pseudomonas aeruginosa (ATCC 25619) (G−) to assess their antimicrobial properties. The results were indeed positive and exhibited good antibacterial effects. Chloroamphenicol used as a standard for comparison and synthesized complexes showed good antibacterial effects over chloroamphenicol. On the basis of these studies, the synthesized complexes help to understand the different structural and biological properties of main group elements with sulfur donor ligands. Copyright © 2010 John Wiley & Sons, Ltd.
TL;DR: A mixture of bis-benzimidazole salts (1−7), Pd(OAc)2 and K2CO3 in DMF H2O catalyzes, in high yield, the Suzuki and Heck cross-coupling reactions assisted by microwave irradiation in a short time, were found to be nearly quantative as mentioned in this paper.
Abstract: A mixture of bis-benzimidazole salts (1–7), Pd(OAc)2 and K2CO3 in DMF H2O catalyzes, in high yield, the Suzuki and Heck cross-coupling reactions assisted by microwave irradiation in a short time. In particular, the yields of the Heck and Suzuki reactions with aryl bromides were found to be nearly quantative. The synthesized bis-benzimidazole salts (1–7) were identified by 1H13C NMR, IR spectroscopic methods and micro analysis. Copyright © 2010 John Wiley & Sons, Ltd.