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Nadine Ritterskamp, Katherine Sharples, Emma Richards, Andrea Folli, Mario Chiesa, James A Platts, Damien M Murphy
The interaction of imidazole with a [Cu(acac)2] complex was studied using electron paramagnetic resonance (EPR), electron nuclear double resonance (ENDOR), hyperfine sublevel correlation spectroscopy (HYSCORE), and density functional theory (DFT). At low Im ratios (Cu:Im 1:10), a 5-coordinate [Cu(acac)2Imn=1] monoadduct is formed in frozen solution with the spin Hamiltonian parameters g1 = 2.063, g2 = 2.063, g3 = 2.307, A1 = 26, A2 = 15, and A3 = 472 MHz with Im coordinating along the axial direction. At higher Im concentrations (Cu:Im 1:50), a 6-coordinate [Cu(acac)2Imn=2] bis-adduct is formed with the spin Hamiltonian parameters g1 = 2...
September 21, 2017: Inorganic Chemistry
Eser S Akturk, Steven J Scappaticci, Rachel N Seals, Michael P Marshak
The synthesis of a sterically encumbered β-diketone ligand ((Ar)acac) substituted with 2,6-(2,4,6-Me3C6H2)2C6H3 is described. Coordination complexes of the type M((Ar)acac)2Cl(solv) (M = Ti, V, Cr; solv = THF, CH3CN) were prepared by the reaction of (Ar)acac with MCl3 (M = V, Cr) or with TiCl4 to generate Ti((Ar)acac)2Cl2, followed by reduction. These complexes show a trend of alternating the cis/trans geometric preference with increasing d(n) electron count (n = 0, 1, 2, 3), which is rationalized in part by the unusual ability of β-diketonates to behave as either a weak π donor or a π acceptor in the cis and trans geometries, respectively...
September 21, 2017: Inorganic Chemistry
Yanouk Cudré, Felipe Franco de Carvalho, Gregory R Burgess, Louise Male, Simon J A Pope, Ivano Tavernelli, Etienne Baranoff
A series of tris-heteroleptic iridium complexes of the form [Ir(C^N(1))(C^N(2))(acac)] combining 2-phenylpyridine (ppy), 2-(2,4-difluorophenyl)pyridine (dFppy), 1-phenylpyrazole (ppz), and 1-(2,4-difluorophenyl)pyrazole (dFppz) as the C^N ligands have been synthesized and fully characterized by NMR, X-ray crystallography, UV-vis absorption and emission spectroscopy, and electrochemical methods. It is shown that "static properties" (e.g., absorption and emission spectra and redox potentials) are primarily dictated by the overall architecture of the complex, while "dynamic properties" (e...
September 18, 2017: Inorganic Chemistry
Concetta Pironti, Raffaele Cucciniello, Federica Camin, Agostino Tonon, Oriana Motta, Antonio Proto
This paper is the first study focused on the innovative application of 13C NMR (Nuclear Magnetic Resonance) spectroscopy to determine the bulk 13C/12C carbon isotope ratio, at natural abundance, in inorganic carbonates and bicarbonates. In the past, 13C NMR spectroscopy (irm-13C NMR) was mainly used to measure isotope ratio monitoring with the potential of conducting 13C position-specific isotope analysis of organic molecules with high precision. The reliability of the newly developed methodology for the determination of stable carbon isotope ratio was evaluated in comparison with the method chosen in the past for these measurements, i...
September 13, 2017: Analytical Chemistry
Thomas Lee, Bertrand Caron, Martin Stroet, David Mark Huang, Paul L Burn, Alan Edward Mark
Atomistic non-equilibrium molecular dynamics simulations have been used to model the induction of anisotropy within the emission layer of an organic light-emitting diode (OLED) formed by vapor deposition. Two emitter species were compared: racemic fac-tris(2-phenylpyridine)iridium(III) (Ir(ppy)3) and trans-bis(2-phenylpyridine)(acetylacetonate) iridium(III) (Ir(ppy)2(acac)). The simulations show that the molecular symmetry axes of both emitters preferentially align perpendicular to the surface during deposition...
September 11, 2017: Nano Letters
Xi Yin, Miao Shi, Jianbo Wu, Yung-Tin Pan, Danielle L Gray, Jeffery A Bertke, Hong Yang
Well-defined metal nanocrystals play important roles in various fields, such as catalysis, medicine, and nanotechnology. They are often synthesized through kinetically controlled process in colloidal systems that contain metal precursors and surfactant molecules. The chemical functionality of surfactants as coordinating ligands to metal ions however remains a largely unsolved problem in this process. Understanding the metal-ligand complexation and its effect on formation kinetics at the molecular level is challenging but essential to the synthesis design of colloidal nanocrystals...
September 11, 2017: Nano Letters
O Kuzmina, N H Hassan, L Patel, C Ashworth, E Bakis, A J P White, P A Hunt, T Welton
Solvatochromic transition metal (TM)-complexes with weakly associating counter-anions are often used to evaluate traditional neutral solvent and anion coordination ability. However, when employed in ionic liquids (IL) many of the common assumptions made are no longer reliable. This study investigates the coordinating ability of weakly coordinating IL anions in traditional solvents and within IL solvents employing a range of solvatochromic copper complexes. Complexes of the form [Cu(acac)(tmen)][X] (acac = acetylacetonate, tmen = tetramethylethylenediamine) where [X](-) = [ClO4](-), Cl(-), [NO3](-), [SCN](-), [OTf](-), [NTf2](-) and [PF6](-) have been synthesised and characterised both experimentally and computationally...
September 28, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
S Carlotto, L Floreano, A Cossaro, M Dominguez, M Rancan, M Sambi, M Casarin
The occupied and unoccupied electronic structures of three high spin TM(acac)3 (TM = Cr, Mn, and Fe) complexes (I, II, and III, respectively) were studied by revisiting their literature vapour-phase He(i) and, when available, He(ii) photoemission (PE) spectra and by means of original near-edge X-ray absorption fine structure (NEXAFS) spectroscopic data recorded at the O K-edge ((O)K-edge) and TM L2,3-edges ((TM)L2,3-edges). The assignments of the vapour-phase He(i)/He(ii) PE spectra were guided by the results of spin-unrestricted non-relativistic Slater transition state calculations, while the (O)K-edge and (TM)L2,3-edge spectroscopic pieces of evidence were analysed by exploiting the results of spin-unrestricted scalar-relativistic time-dependent density functional theory (DFT) and DFT/ROCIS calculations, respectively...
September 20, 2017: Physical Chemistry Chemical Physics: PCCP
Andrey V Gavrikov, Nikolay N Efimov, Zhanna V Dobrokhotova, Andrey B Ilyukhin, Pavel N Vasilyev, Vladimir M Novotortsev
A series of novel isomorphic mononuclear complexes [Ln(PyrCOO)(acac)2(H2O)2] (Ln = Eu (1), Gd (2), Tb (3), Dy (4), Ho (5), Er (6), Tm (7), Yb (8), Y(9); acac(-) - acetylacetonate (pentane-2,4-dionate) anion, PyrCOOH is pyrazine-2-carboxylic acid) were prepared. Slow magnetic relaxation indicating SMM behavior was found in complexes 3, 4, 6 and 8. For 4 (Dy), the anisotropy barrier is Δeff/kB = 77 K under a dc field of 1500 Oe. For 8 (Yb), the anisotropy barrier is Δeff/kB = 54 K under a dc field of 2000 Oe which is the highest presently known value for molecular Yb carboxylate complexes and for Yb molecular complexes in general...
September 12, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Taro Sonehara, Shogo Murakami, Sae Yamazaki, Motoi Kawatsura
We demonstrate the iron-catalyzed intermolecular coupling of internal alkynes and thiosalicylic acid derivatives. The reaction was effectively catalyzed by the Fe(acac)2/1,10-phenanthroline catalyst in toluene/HFIP (hexafluoroisopropyl alcohol) as the reaction solvent and afforded several types of 1,3-oxathiine derivatives in moderate to high yields through the intermolecular hydrothiolation and sequential intramolecular cyclization.
August 7, 2017: Organic Letters
Farshad Beshkar, Hossein Khojasteh, Masoud Salavati-Niasari
In this work we have demonstrated a facile formation of CuO nanostructures on copper substrates by the oxidation of copper foil in ethylene glycol (EG) at 80 °C. On immersing a prepared CuO film into a solution containing 0.1 g Zn(acac)₂ in 20 mL EG for 8 h, ZnO flower-like microstructures composed of hierarchical three-dimensional (3D) aggregated nanoparticles and spherical architectures were spontaneously formed at 100 °C. The as-synthesized thin films and 3D microstructures were characterized using XRD, SEM, and EDS techniques...
June 25, 2017: Materials
Da-Hua Wei, Ko-Ying Pan, Sheng-Kai Tong
The chemical reduction of ferric acetylacetonate (Fe(acac)₃) and platinum acetylacetonate (Pt(acac)₂) using the polyol solvent of phenyl ether as an agent as well as an effective surfactant has successfully yielded monodispersive FePt nanoparticles (NPs) with a hydrophobic ligand and a size of approximately 3.8 nm. The present FePt NPs synthesized using oleic acid and oleylamine as the stabilizers under identical conditions were achieved with a simple method. The surface modification of FePt NPs by using mercaptoacetic acid (thiol) as a phase transfer reagent through ligand exchange turned the NPs hydrophilic, and the FePt NPs were water-dispersible...
February 15, 2017: Materials
Seyyed Muhammad Salili, Matthew Worden, Ahlam Nemati, Donald W Miller, Torsten Hegmann
A room temperature reduction-hydrolysis of Fe(III) precursors such as FeCl₃ or Fe(acac)₃ in various lyotropic liquid crystal phases (lamellar, hexagonal columnar, or micellar) formed by a range of ionic or neutral surfactants in H₂O is shown to be an effective and mild approach for the preparation of iron oxide (IO) nanomaterials with several morphologies (shapes and dimensions), such as extended thin nanosheets with lateral dimensions of several hundred nanometers as well as smaller nanoflakes and nanodiscs in the tens of nanometers size regime...
August 2, 2017: Nanomaterials
Xia Jiang, Guang-Hui Chen, Min-Qiang Gu, Qiang Wang, Di Wu
Density functional theory (DFT) and time-dependent DFT calculations were performed to evaluate the influence of substituent effect of (1) R = 4-Me, (2) R = 4-OMe, and (3) R = 2,3-OC6H4 on the phenyl ring of (C(∧)C*)Pt(II)(acac) (C(∧)C* = phenylimidazole, acac = acetylacetone), respectively, on absorption and phosphorescent spectra properties, as well as the radiative and nonradiative processes. We found that emissions of complexes 2 and 3 originate from the Kasha-like T1 state, whereas that of complex 1 originates from non-Kasha T2 state...
August 15, 2017: Journal of Physical Chemistry. A
Syed Awais Rouf, Vibe Boel Jakobsen, Jiří Mareš, Nicholai Daugaard Jensen, Christine J McKenzie, Juha Vaara, Ulla Gro Nielsen
Recent advances in computational methodology allowed for first-principles calculations of the nuclear shielding tensor for a series of paramagnetic nickel(II) acetylacetonate complexes, [Ni(acac)2L2] with L = H2O, D2O, NH3, ND3, and PMe2Ph have provided detailed insight into the origin of the paramagnetic contributions to the total shift tensor. This was employed for the assignment of the solid-state (1,2)H and (13)C MAS NMR spectra of these compounds. The two major contributions to the isotropic shifts are by orbital (diamagnetic-like) and contact mechanism...
July 17, 2017: Solid State Nuclear Magnetic Resonance
Craig M Lieberman, Matthew C Barry, Zheng Wei, Andrey Yu Rogachev, Xiaoping Wang, Jun-Liang Liu, Rodolphe Clérac, Yu-Sheng Chen, Alexander S Filatov, Evgeny V Dikarev
A series of mixed-valent, heterometallic (mixed-transition metal) diketonates that can be utilized as prospective volatile single-source precursors for the low-temperature preparation of MxM'3-xO4 spinel oxide materials is reported. Three iron-cobalt complexes with Fe/Co ratios of 1:1, 1:2, and 2:1 were synthesized by several methods using both solid-state and solution reactions. On the basis of nearly quantitative reaction yields, elemental analyses, and comparison of metal-oxygen bonds with those in homometallic analogues, heterometallic compounds were formulated as [Fe(III)(acac)3][Co(II)(hfac)2] (1), [Co(II)(hfac)2][Fe(III)(acac)3][Co(II)(hfac)2] (2), and [Fe(II)(hfac)2][Fe(III)(acac)3][Co(II)(hfac)2] (3)...
July 31, 2017: Inorganic Chemistry
Long-Fei Wang, Jiang-Zhen Qiu, Jun-Yu Hong, Yan-Cong Chen, Quan-Wen Li, Jian-Hua Jia, Jesús Jover, Eliseo Ruiz, Jun-Liang Liu, Ming-Liang Tong
The dimeric molecule [Dy2(acac)6(MeOH)2(bpe)]·bpe·2MeOH (1, acac = acetylacetonate, bpe = 1,2-bis(4-pyridyl)ethylene) undergoes a solid-state ligand substitution reaction upon heating, leading to the one-dimensional chain [Dy(acac)3(bpe)]n (2). This structural transformation takes advantage of the potential coordination of the guest bpe molecules present in 1. In both complexes the Dy(III) ions adopt similar octacoordinated D4d geometries. However, the different arrangement of the negatively charged and neutral ligands alters the direction of magnetic anisotropy axis and the energy states, thus resulting in largely distinct magnetization dynamics, as revealed by the CASSCF/RASSI calculations...
August 7, 2017: Inorganic Chemistry
E Croteau, C A Castellano, M Fortier, C Bocti, T Fulop, N Paquet, S C Cunnane
INTRODUCTION: Deteriorating brain glucose metabolism precedes the clinical onset of Alzheimer's disease (AD) and appears to contribute to its etiology. Ketone bodies, mainly β-hydroxybutyrate and acetoacetate, are the primary alternative brain fuel to glucose. Some reports suggest that brain ketone metabolism is unchanged in AD but, to our knowledge, no such data are available for MCI. OBJECTIVE: To compare brain energy metabolism (glucose and acetoacetate) and some brain morphological characteristics in cognitively healthy older adult controls (CTL), mild cognitive impairment (MCI) and early AD...
July 12, 2017: Experimental Gerontology
Antonella Muscella, Carla Vetrugno, Luca Giulio Cossa, Giovanna Antonaci, Amilcare Barca, Sandra Angelica De Pascali, Francesco Paolo Fanizzi, Santo Marsigliante
Mesothelioma cancer cells have epithelioid or sarcomatoid morphology. The worst prognosis is associated with sarcomatoid phenotype and resistance to therapy is affected by cells heterogeneity. We recently showed that in ZL55 mesothelioma cell line of epithelioid origin [Pt(O,O'-acac)(γ-acac)(DMS)] (Ptac2S) has an antiproliferative effect in vitro and in vivo. Aim of this work was to extend the study on the effects of Ptac2S on ZL34 cell line, representative of sarcomatoid mesothelioma. ZL34 cells were used to assay the antitumor activity of Ptac2S in a mouse xenograft model in vivo...
2017: PloS One
U Suyasunanont, M Nakkuntod, S Mirasena
The lower northern part of Thailand contains various genetically diverse ethnic populations. The sequences of the mitochondrial DNA hypervariable region were studied in three ethnic populations inhabiting Phitsanulok Province. One hundred and nine nucleotide sequences - 53, 29, and 27 from Hmongs (Hill tribe), Lao Songs, and Thai-Siams, respectively - were collected. The haplotypes were generated from 1130 nucleotides of the entire control region. Eighty-six haplotypes were found in the three ethnic populations, and no shared haplotypes were found between populations...
July 6, 2017: Genetics and Molecular Research: GMR
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