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David R Diercks, Brian P Gorman, Johannes J L Mulders
Six precursors were evaluated for use as in situ electron beam-induced deposition capping layers in the preparation of atom probe tomography specimens with a focus on near-surface features where some of the deposition is retained at the specimen apex. Specimens were prepared by deposition of each precursor onto silicon posts and shaped into sub-70-nm radii needles using a focused ion beam. The utility of the depositions was assessed using several criteria including composition and uniformity, evaporation behavior and evaporation fields, and depth of Ga+ ion penetration...
October 17, 2016: Microscopy and Microanalysis
Benjamin E Van Kuiken, Anselm W Hahn, Dimitrios Maganas, Serena DeBeer
Spectroscopic probes of the electronic structure of transition metal-containing materials are invaluable to the design of new molecular catalysts and magnetic systems. Herein, we show that 2p3d resonant inelastic X-ray scattering (RIXS) can be used to observe both spin-allowed and (in the V(III) case) spin-forbidden d-d excitation energies in molecular vanadium complexes. The spin-allowed d-d excitation energies determined by 2p3d RIXS are in good agreement with available optical data. In V(acac)3, a previously undetected spin-forbidden singlet state has been observed...
October 12, 2016: Inorganic Chemistry
Mannar R Maurya, Bithika Sarkar, Fernando Avecilla, Isabel Correia
The ONO donor ligands obtained from the condensation of 4-benzoyl-3-methyl-1-phenyl-2-pyrazoline-5-one (Hbp) with benzoylhydrazide (H2bp-bhz I), furoylhydrazide (H2bp-fah II), nicotinoylhydrazide (H2bp-nah III) and isonicotinoylhydrazide (H2bp-inh IV), upon treatment with [V(IV)O(acac)2], lead to the formation of [V(IV)O(bp-bhz)(H2O)] 1, [V(IV)O(bp-fah)(H2O)] 2, [V(IV)O(bp-nah)(H2O)] 3 and [V(IV)O(bp-inh)(H2O)] 4, respectively. At neutral pH the in situ generated aqueous K[H2V(V)O4] reacts with ligands I and II, forming potassium salts, K(H2O)2[V(V)O2(bp-bhz)] 5 and K(H2O)2[V(V)O2(bp-fah)] 6, while ligands III and IV give neutral complexes, [V(V)O2(Hbp-nah)] 9 and [V(V)O2(Hbp-inh)] 10, respectively...
October 10, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Práxedes Sánchez, Martín Hernández-Juárez, Eleuterio Álvarez, Margarita Paneque, Nuria Rendón, Andrés Suárez
Coordination studies of new lutidine-derived hybrid NHC/phosphine ligands (CNP) to Pd and Ir have been performed. Treatment of the square-planar [Pd(CNP)Cl](AgCl2) complex 2a with KHMDS produces the selective deprotonation at the CH2P arm of the pincer to yield the pyridine-dearomatised complex 3a. A series of cationic [Ir(CNP)(cod)](+) complexes 4 has been prepared by reaction of the imidazolium salts 1 with Ir(acac)(cod). These derivatives exhibit in the solid state, and in solution, a distorted trigonal bipyramidal structure in which the CNP ligands adopt an unusual C(axial)-N(equatorial)-P(equatorial) coordination mode...
October 4, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Minzhi Peng, Yanna Cai, Xiefan Fang, Li Liu
A novel liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been established to quantify metabolic intermediates, including lactate (Lac), pyruvate (Pyr), acetoacetate (ACAC) and 3-hydroxybutyrate (3-HB) in blood. Samples were deproteinized with methanol-acetonitrile solution, and analytes were separated on an adamantyl group-bonded reverse phase column and detected in multiple reaction monitoring mode. Total analysis time was 4 min per sample. Method validation results displayed that limits of quantification were 10...
October 26, 2016: Analytica Chimica Acta
Anne E V Gorden, Michael L McKee
The stability of Th(4+) to reduction in water is studied by DFT methods. The standard reduction potential (SRP) of homoleptic complexes including Th(H2O)9(4+), Th(H2O)10(4+), Th(NO3)4, Th(NO2)6(2-), Th(NO3)6(2-), Th(COT)2, Th(acac)4, ThCp4, ThF4, and ThCl4 have been investigated. The values vary widely (from -3.50 V for Th(OH)4 to -0.62 V for Th(NO3)4 depending on whether the ligands are redox active (noninnocent) or not. Several additional topics of thorium chemistry are explored, including the hydrolysis mechanism of ThO2(H2O)n, n = 1, 2, 4, and the solution phase nonzero dipole moment of ThCp4...
October 7, 2016: Journal of Physical Chemistry. A
Lalita B Rane, Anup N Kate, Shefali N Ramteke, Bhupendra V Shravage, Prasad P Kulkarni, Anupa A Kumbhar
Two new zinc(ii) complexes, [Zn(l-His)(NIP)](+)(1) and [Zn(acac)2(NIP)](2) (where NIP is 2-(naphthalen-1-yl)-1H-imidazo[4,5-f][1,10]phenanthroline, acac = acetyl acetone), have been synthesized and characterized by elemental analysis, UV-vis, fluorescence, IR, (1)H NMR and electron spray ionization mass spectroscopies. Gel retardation assay, atomic force microscopy and dynamic light scattering studies show that 1 and 2 can induce the condensation of circular plasmid pBR322 DNA into nanometer size particles under ambient conditions...
October 3, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Cristina Trejo-Solis, Mayra A Alvarez-Lemus, Dolores Jiménez-Farfán, Isabel Anaya-Rubio, Rosendo López-González, Guadalupe Palencia, Dora M Frías-Márquez, Gerardo González-García, Carmen Rubio-Osornio, Minerva Calvillo-Velasco, Guadalupe Márquez-Chablé
Phenanthroline derivatives have been reported as potential bioactive compounds because of their ability to interact with DNA. In order to evaluate the antiproliferative effect of bis(acetylacetonate-k(2) O,O)(1,10-phenanthroline-k(2) N,N)Zn(II) or Zn(acac)2 (phen) complex, the compound was obtained in a simple manner and further characterized to determine crystal structure, thermal behavior, morphology and spectroscopic properties. The structure of the complex was confirmed by X-Ray single structure as well as by solution solid-state (13) C CP/MAS NMR...
October 2, 2016: Chemical Biology & Drug Design
Xiaoxia Shi, Dangdang Li, Qinghua Deng, Zhicheng Peng, Chenxu Zhao, Xiaobing Li, Zhe Wang, Xinwei Li, Guowen Liu
Dairy cows with fatty liver or ketosis exhibit hyperketonemia, oxidative stress, and a low rate of very low density lipoprotein (VLDL) assembly, and there may be a potential link among these characteristics. Therefore, the objective of this study was to determine the effect of acetoacetic acid (AcAc) on the assembly of VLDL in cow hepatocytes. Cultured cow hepatocytes were treated with different concentrations of AcAc with or without N-acetylcysteine (NAC, an antioxidant). AcAc treatment decreased the mRNA expression and activities of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px), and significantly increased malondialdehyde (MDA) content, indicative of oxidative stress...
October 3, 2016: Journal of Dairy Research
Shanghua Xia, Lu Gan, Kailiang Wang, Zheng Li, Dawei Ma
The combination of Cu(acac)2 and N,N'-bis(4-hydroxyl-2,6-dimethylphenyl)oxalamide (BHMPO) provides a powerful catalytic system for hydroxylation of (hetero)aryl halides. A wide range of (hetero)aryl chlorides bearing either electron-donating or -withdrawing groups proceeded well at 130 °C, delivering the corresponding phenols and hydroxylated heteroarenes in good to excellent yields. When more reactive (hetero)aryl bromides and iodides were employed, the hydroxylation reactions completed at relatively low temperatures (80 and 60 °C, respectively) at low catalytic loadings (0...
October 5, 2016: Journal of the American Chemical Society
Jiahui Kong, Qiong Zhang, Mathew Savage, Minzhi Li, Xin Li, Sihai Yang, Xu Liang, Weihua Zhu, Hans Ågren, Yongshu Xie
By oxidation of an alternately N-confused bilane in CH2Cl2, a C-N fused tetrapyrrin was synthesized that bears a 5.5.5-tricyclic ring generated from an intramolecular C-N linkage. When CH3CN was used as the reaction medium, a multiply C-N-fused octapyrrolic dimer was also obtained that contained two moieties and a bipyrrole unit generated from the intramolecular C-N linkage and intermolecular C-C linkage, respectively. This could be coordinated with Ni(acac)2 to afford a mixed-ligand complex...
October 7, 2016: Organic Letters
Miika Mattinen, Jani Hämäläinen, Feng Gao, Pasi Jalkanen, Kenichiro Mizohata, Jyrki Räisänen, Riikka L Puurunen, Mikko Ritala, Markku Leskelä
Nucleation and conformality are important issues, when depositing thin films for demanding applications. In this study, iridium and iridium dioxide (IrO2) films were deposited by atomic layer deposition (ALD), using five different processes. Different reactants, namely, O2, air, consecutive O2 and H2 (O2 + H2), and consecutive O3 and H2 (O3 + H2) pulses were used with iridium acetylacetonate [Ir(acac)3] to deposit Ir, while IrO2 was deposited using Ir(acac)3 and O3. Nucleation was studied using a combination of methods for film thickness and morphology evaluation...
October 6, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Feng-Min Li, Xiao-Qian Wang
Cancer is one of the main causes of threats to human life. Identification of anticancer peptides is important for developing effective anticancer drugs. In this paper, we developed an improved predictor to identify the anticancer peptides. The amino acid composition (AAC), the average chemical shifts (acACS) and the reduced amino acid composition (RAAC) were selected to predict the anticancer peptides by using the support vector machine (SVM). The overall prediction accuracy reaches to 93.61% in jackknife test...
September 27, 2016: Scientific Reports
Jin-Xian Lei, Jing Wang, Yang Huo, Zhonglu You
A hydrated hydrazone compound, 4-fluoro-N'-(2-hydroxy-3-methoxybenzylidene)benzohydrazide monohydrate (H2L · H2O), was prepared and characterized by elemental analysis, HRMS, IR, UV-Vis and 1H NMR spectroscopy. Reaction of H2L, kojic acid (5-hydroxy-2-(hydroxymethyl)-4H-pyran-4-one; Hka) and VO(acac)2 in methanol afforded a novel oxidovanadium(V) complex, [VO(ka)L]. The complex was characterized by elemental analysis, IR, UV-Vis and 1H NMR spectroscopy. Thermal analysis was also performed. Structures of H2L and the complex were further confirmed by single crystal structural X-ray diffraction...
2016: Acta Chimica Slovenica
Alexandre Courchesne-Loyer, Etienne Croteau, Christian-Alexandre Castellano, Valérie St-Pierre, Marie Hennebelle, Stephen C Cunnane
Ketones (principally β-hydroxybutyrate and acetoacetate (AcAc)) are an important alternative fuel to glucose for the human brain, but their utilisation by the brain remains poorly understood. Our objective was to use positron emission tomography (PET) to assess the impact of diet-induced moderate ketosis on cerebral metabolic rate of acetoacetate (CMRa) and glucose (CMRglc) in healthy adults. Ten participants (35 ± 15 y) received a very high fat ketogenic diet (KD) (4.5:1; lipid:protein plus carbohydrates) for four days...
September 14, 2016: Journal of Cerebral Blood Flow and Metabolism
Jing-Xuan Wu, Yi-Hua Hong, Xiao-Gai Yang
In this study, the antiproliferative effect of bis(acetylacetonato)-oxidovanadium(IV) and sodium metavanadate and the underlying mechanisms were investigated in human pancreatic cancer cell line AsPC-1. The results showed that both exhibited an antiproliferative effect through inducing G2/M cell cycle arrest and can also cause elevation of reactive oxygen species (ROS) levels in cells. Moreover, the two vanadium compounds induced the activation of both PI3K/AKT and MAPK/ERK signaling pathways dose- and time-dependently, which could be counteracted with the antioxidant N-acetylcysteine...
September 10, 2016: Journal of Biological Inorganic Chemistry: JBIC
Kathleen M Fleming, Jennifer C Pekar, Brian D Leskiw
RATIONALE: While much of the interest and application of beta-diketonate complexes has focused predominately on the condensed phases, we report on the prevalence of gas-phase ligand exchange reactions leading to the formation of novel species. METHODS: Gas-phase ligand exchange reactions of Mg(eeac)2 and Mg(tftm)2 complexes with Cu(acac)2 , Cu(tftm)2 , Cu(dbm)2 , and Cu(eeac)2 were investigated using a direct insertion electron impact triple quadrupole mass spectrometer...
November 30, 2016: Rapid Communications in Mass Spectrometry: RCM
Tao Xu, Weiling Li, Xicun Gao, Chang Sun, Guo Chen, Xiaowen Zhang, Chunya Li, Wenqing Zhu, Bin Wei
This paper demonstrates the influence of temperature, exciton concentration, and electron transportation layers on the excimer emission of a novel deep-blue material: 4,4'-bis(4''-triphenylsilyl) phenyl-1,1'-binaphthalene (SiBN), by studying the photoluminescence and electroluminescence spectra of SiBN-based film. We have further developed sunlight-like and warm-light white organic light-emitting diodes (WOLEDs) with high efficiency and wide-range spectra, using SiBN and bis(2-phenylbenzothiozolato-N,C2')iridium(acetylacetonate) (bt2Ir(acac)) as the blue excimer and yellow materials, respectively...
December 2016: Nanoscale Research Letters
Tobias Parchomyk, Konrad Koszinowski
Iron-catalyzed cross-coupling reactions have an outstanding potential for sustainable organic synthesis, but remain mechanistically poorly understood. Here, we use electrospray-ionization (ESI) mass spectrometry to identify the ionic species formed in these reactions and characterize their reactivity. Transmetalation of Fe(acac) (acac = acetylacetonato) with PhMgCl in tetrahydrofuran (THF) produces anionic iron ate complexes, whose nuclearity (1 to 4 Fe centers) and oxidation state (ranging from -I to +III) crucially depend on the presence of additives or ligands...
August 24, 2016: Chemistry: a European Journal
Huifang Li, Lisheng Zhang, Lvyin Zheng, Xun Li, Xiaolin Fan, Yi Zhao
Phototriggered intramolecular isomerization in a series of ruthenium sulfoxide complexes, [Ru(L)(tpy)(DMSO)](n+) (where tpy=2,2':6',2''-terpyridine; DMSO=dimethyl sulfoxide; L=2,2'-bipyridine (bpy), n=2; N,N,N',N'-tetramethylethylenediamine (tmen) n=2; picolinate (pic), n=1; acetylacetonate (acac), n=1; oxalate (ox), n=0; malonate (mal), n=0), was investigated theoretically. It is observed that the metal-centered ligand field ((3) MC) state plays an important role in the excited state S→O isomerization of the coordinated DMSO ligand...
September 26, 2016: Chemistry: a European Journal
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