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https://www.readbyqxmd.com/read/29793025/simultaneous-immobilization-of-borate-arsenate-and-silicate-from-geothermal-water-derived-from-mining-activity-by-co-precipitation-with-hydroxyapatite
#1
Keiko Sasaki, Yoshikazu Hayashi, Kenta Toshiyuki, Binglin Guo
The treatment of the geothermal water discharged through mining activity is a critical issue because the rate of discharge is 12,000 m3 per day and the discharge contains high concentrations of borate (>20 mg/L) and arsenate (ca. 0.4 mg/L) as well as silicate and carbonate. The simultaneous reduction of borate and arsenate concentrations to acceptable levels was successfully performed by co-precipitation with hydroxyapatite (HAp). Although the coexisting high concentrations of carbonate act as a disturbing element, the co-precipitation equilibrium of borate was shifted to lower values by adjusting the P/Ca molar ratio, and the removal rate of borate was accelerated by using Al3+ additives, resulting in the efficient reduction of borate within 1 h...
May 16, 2018: Chemosphere
https://www.readbyqxmd.com/read/29792418/self-assembled-pd-ii-6-molecular-spheroids-and-their-proton-conduction-property
#2
Rupak Saha, Aloke Kumar Ghosh, Rudra Narayan Samajdar, Partha Sarathi Mukherjee
A series of molecular spheroids (SP1-SP4) was synthesized using pseudolinear bisimidazole and bisbenzimidazole donors in combination with Pd(NO3 )2 acceptor via coordination-driven self-assembly. They were characterized by NMR and mass spectrometry, and the solid-state structures of SP1 and SP3 were confirmed by X-ray diffraction. Crystal packing revealed the presence of molecular channels with water molecules in the channels as proton source. All the systems showed proton conductivity across a wide range of temperature and relative humidity...
May 24, 2018: Inorganic Chemistry
https://www.readbyqxmd.com/read/29792320/modular-cavities-induced-fit-of-polar-and-apolar-guests-into-halogen-based-receptors
#3
Kentaro Aoki, Kazuya Otsubo, Garry S Hanan, Kunihisa Sugimoto, Hiroshi Kitagawa
Neutral triangular macrocyclic compounds, [PdX2 (4,7-phen)]3 ·(DMF)3 ·Et2 O (X = Cl, Br; 4,7-phen = 4,7-phenanthroline; DMF = N, N'-dimethylformamide; Et2 O = diethyl ether), were synthesized, and their molecular structures were characterized. Solution-state 1 H NMR results suggested the formation of metal-ligand bonds, and single-crystal X-ray crystallography revealed clear triangular structures. A detailed examination of the structures indicated the formation of two kinds of cavities in the solid state, where a triangular unit works as a halogen-based receptor for polar and apolar solvents through weak hydrogen-bonding and dipole-dipole interaction...
May 24, 2018: Inorganic Chemistry
https://www.readbyqxmd.com/read/29792028/in-situ-structural-elucidation-and-selective-pb2-ion-recognition-of-polydopamine-film-formed-by-controlled-electrochemical-oxidation-of-dopamine
#4
K S Shalini Devi, Sharu Jacob, Annamalai Senthil Kumar
Owing to the versatility and biocompatibility, a self-polymerized DA (in presence of air at pH 8.5 tris buffer solution) as a polydopamine (pDA) film has been used for a variety of applications. Indeed, instability under electrified condition (serious surface-fouling) and structural ambiguity of the pDA have been found to be unresolved problems. Previously, pDA films (has hygroscopic and insoluble property) prepared by various controlled chemical oxidation methods have been examined for the structural analysis using ex-situ solid-state NMR and Mass Spectroscopic techniques...
May 24, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/29791041/polymorphism-weak-interactions-and-phase-transitions-in-chalcogen-phosphorus-heterocycles
#5
Paula Sanz Camacho, Martin Stanford, David McKay, Daniel Dawson, Kasun Athukorala Arachchige, David Cordes, Alexandra Slawin, Derek Woollins, Sharon E Ashbrook
A series of novel P-E containing heterocycles with aromatic backbones were synthesised and characterized by single crystal and powder X-ray diffraction, microanalysis and mass spectrometry. 31P and 77Se solution- and solid-state NMR spectroscopy revealed significant differences between the NMR parameters in solution and in the solid state, related to conformational changes in the molecules. Many compounds were shown to exhibit a number of different polymorphic structures (identified by single-crystal XRD), although the bulk material studied by solid-state NMR often contained just one major polymorph...
May 23, 2018: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29786921/room-temperature-ferroelectricity-in-an-organic-cocrystal
#6
Adam J Matzger, Ren A Wiscons, Nagula Rajesh Goud, Joshua T Damron
Ferroelectric materials exhibit switchable remanent polarization due to reversible symmetry breaking under an applied electric field. Previous research has leveraged temperature-induced neutral-ionic transitions in charge-transfer (CT) cocrystals to access ferroelectrics that operate through displacement of molecules under an applied field. However, displacive ferroelectric behavior is rare in organic CT cocrystals and achieving a Curie temperature (TC) above ambient has been elusive. Here a cocrystal between acenaphthene and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane is presented that shows switchable remanent polarization at room temperature (TC = 68°C)...
May 22, 2018: Angewandte Chemie
https://www.readbyqxmd.com/read/29786717/comparison-of-hydroxycarboxylato-imidazole-molybdenum-iv-complexes-and-nitrogenase-protein-structures-indirect-evidence-for-the-protonation-of-homocitrato-femo-cofactors
#7
Si-Yuan Wang, Wan-Ting Jin, Hong-Bin Chen, Zhao-Hui Zhou
Glycolato and R,S-lactato imidazole molybdenum(iv) complexes [Mo3SO3(glyc)2(im)5]·im·H2O (1), Na2[Mo3SO3(R,S-lact)3(im)3]·10H2O (2), and [Mo6O10(R,S-lact)2(im)10]·16H2O (3) have been isolated and characterized (H2glyc = glycolic acid, H2lact = lactic acid, im = imidazole). α-Alkoxy coordination with molybdenum [Mo-Oα-alkoxy 1.993(7)av Å] in 1 and 2 showed obvious differences to their counterpart with α-hydroxy coordination [MoIV3S4(PPh3)3(Hlact)2(lact)] [2.204(4)av Å] as shown in M. N. Sokolov, S. A...
May 22, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/29785460/rapid-measurement-of-long-range-distances-in-proteins-by-multidimensional-13-c-19-f-redor-nmr-under-fast-magic-angle-spinning
#8
Alexander A Shcherbakov, Mei Hong
The ability to simultaneously measure many long-range distances is critical to efficient and accurate determination of protein structures by solid-state NMR (SSNMR). So far, the most common distance constraints for proteins are 13 C-15 N distances, which are usually measured using the rotational-echo double-resonance (REDOR) technique. However, these measurements are restricted to distances of up to ~ 5 Å due to the low gyromagnetic ratios of 15 N and 13 C. Here we present a robust 2D 13 C-19 F REDOR experiment to measure multiple distances to ~ 10 Å...
May 21, 2018: Journal of Biomolecular NMR
https://www.readbyqxmd.com/read/29785431/slow-magnetic-relaxation-and-luminescence-properties-in-lanthanide-iii-anil-complexes
#9
Diamantoula Maniaki, Ioannis Mylonas-Margaritis, Julia Mayans, Aikaterini Savvidou, Catherine P Raptopoulou, Vlasoula Bekiari, Vassilis Psycharis, Albert Escuer, Spyros P Perlepes
The initial use of anils, i.e. bidentate Schiff bases derived from the condensation of anilines with salicylaldehyde or its derivatives, in 4f-metal chemistry is described. The 1 : 1 reactions between Ln(NO3)3·xH2O (Ln = lanthanide) or Y(NO3)3·6H2O and N-(5-bromosalicylidene)aniline (5BrsalanH) in MeCN has provided access to complexes [Ln(NO3)3(5BrsalanH)2(H2O)]·MeCN (Ln = Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb) and [Y(NO3)3(5BrsalanH)2(H2O)]·MeCN, respectively, in good yields. The structures of the isomorphous complexes with Ln = Pr(1·MeCN), Sm(3·MeCN), Gd(5·MeCN), Dy(7·MeCN) and Er(9·MeCN) have been determined by single-crystal X-ray crystallography...
May 22, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/29783734/void-formation-elimination-and-viscoelastic-response-of-polyphenylsilsesquioxane-monolith
#10
Yusuke Daiko, Yuki Oda, Sawao Honda, Yuji Iwamoto
Polyphenylsilsesquioxane (PhSiO3/2 ) particles as an organic-inorganic hybrid were prepared using sol-gel method, and monolithic samples were obtained via a warm-pressing. The reaction mechanism of particles' polymerization and transformation to the monolith under the warm-press were investigated using solid state 29 Si nuclear magnetic resonance (NMR) spectrometer, thermal gravimetric-differential thermal analyzer (TG-DTA), mass spectrometer (MS) and scanning electron microscope (SEM). Transparent and void-free monoliths are successfully obtained by warm-pressing above 180 °C...
May 19, 2018: Materials
https://www.readbyqxmd.com/read/29783633/butyrylation-of-maize-and-potato-starches-and-characterization-of-the-products-by-nuclear-magnetic-resonance-and-in-vitro-fermentation
#11
Tina Skau Nielsen, Nuria Canibe, Flemming Hofmann Larsen
Intake of butyrylated starches may increase colonic butyrate supply, which can be of public health and clinical benefit by maintaining colonic health. The objective was to investigate if an organocatalytic method with tartaric acid as a catalyst could be applied to produce butyrylated products from different starch sources and to characterize their chemical structure and fermentation capability by using solid-state 13 C MAS NMR (magic angle spinning nuclear magnetic resonance) spectroscopy and an in vitro fermentation model, respectively...
May 18, 2018: Foods (Basel, Switzerland)
https://www.readbyqxmd.com/read/29782805/maintaining-supersaturation-of-nimodipine-by-pvp-with-or-without-the-presence-of-sodium-lauryl-sulfate-and-sodium-taurocholate
#12
Yipshu Pui, Yuejie Chen, Huijun Chen, Shan Wang, Chengyu Liu, Wouter Tonnis, Linc Chen, Peter Serno, Stefan Bracht, Feng Qian
Amorphous solid dispersion (ASD) is one of the most versatile supersaturating drug delivery system to improve the dissolution rate and oral bioavailability of poorly water soluble drugs. PVP based ASD formulation of nimodipine (NMD) has been marketed and effectively used in clinic for nearly 30 years, yet the mechanism by which PVP maintains the supersaturation and subsequently improves the bioavailability of NMD was rarely investigated. In this research, we first studied the molecular interactions between NMD and PVP by solution NMR using CDCl3 as the solvent, and drug-polymer Flory-Huggins interaction parameter...
May 21, 2018: Molecular Pharmaceutics
https://www.readbyqxmd.com/read/29782692/the-influence-of-chemical-modification-on-linker-rotational-dynamics-in-metal-organic-frameworks
#13
Joshua Damron, Jialiu Ma, Ricardo Kurz, Kay Saalwaechter, Adam Matzger, Ayyalusamy Ramamoorthy
The robust synthetic flexibility of metal-organic frameworks (MOFs) offers a promising class of tailorable materials, for which, the ability to tune specific physicochemical properties is highly desired. This is achievable only through a thorough description of the consequences for chemical manipulations both in structure and dynamics. Magic angle spinning solid-state NMR spectroscopy offers many modalities in this pursuit, particularly for dynamic studies. Herein, we employ a separated-local-field NMR approach to show how specific intra-framework chemical modifications to MOF UiO66 heavily modulate the dynamic evolution of the organic ring moiety over several orders of magnitude...
May 21, 2018: Angewandte Chemie
https://www.readbyqxmd.com/read/29781190/in-situ-study-of-the-functions-of-bacterioruberin-in-the-dual-chromophore-photoreceptor-archaerhodopsin-4
#14
Chao Sun, Xiaoyan Ding, Haolin Cui, Yanan Yang, Sijin Chen, Anthony Watts, Xin Zhao
While certain archaeal ion pumps have been shown to contain two chromophores, retinal and carotenoid bacterioruberin, the functions of the bacterioruberin have not been well explored. To address this research gap, the recombinant archaerhodopsin-4 (aR4), either with retinal chromophore only or with both retinal and bacterioruberin chromophores, was successfully expressed together with endogenous lipids in H. salinarum L33 and MPK409 respectively. In situ solid-state NMR, supported by molecular spectroscopy and functional assays, revealed for the first time that the retinal thermal equilibrium in the dark-adapted state is modulated by bacterioruberin binding via a cluster of aromatic residues on helix E...
May 20, 2018: Angewandte Chemie
https://www.readbyqxmd.com/read/29780509/self-complementary-nickel-halides-enable-multifaceted-comparisons-of-intermolecular-halogen-bonds-fluoride-ligands-vs-other-halides
#15
Vargini Thangavadivale, Pedro M Aguiar, Naseralla A Jasim, Sarah J Pike, Dan A Smith, Adrian C Whitwood, Lee Brammer, Robin N Perutz
The syntheses of three series of complexes designed with self-complementary motifs for formation of halogen bonds between an iodotetrafluorophenyl ligand and a halide ligand at square-planar nickel are reported, allowing structural comparisons of halogen bonding between all four halides C6 F4 I···X-Ni (X = F, Cl, Br, I). In the series trans -[NiX(2,3,5,6-C6 F4 I)(PEt3 )2 ] 1pX and trans -[NiX(2,3,4,5-C6 F4 I)(PEt3 )2 ] (X = F, Cl, Br, I) 1oX , the iodine substituent on the benzene ring was positioned para and ortho to the metal, respectively...
April 21, 2018: Chemical Science
https://www.readbyqxmd.com/read/29780484/exploiting-the-interactions-between-the-ruthenium-hoveyda-grubbs-catalyst-and-al-modified-mesoporous-silica-the-case-of-sba15-vs-kcc-1
#16
Baraa Werghi, Eva Pump, Mykyta Tretiakov, Edy Abou-Hamad, Andrei Gurinov, Pradeep Doggali, Dalaver H Anjum, Luigi Cavallo, Anissa Bendjeriou-Sedjerari, Jean-Marie Basset
Immobilization of the 2nd generation Hoveyda-Grubbs catalyst HG-II onto well-ordered 2D hexagonal (SBA15) and 3D fibrous (KCC-1) mesostructured silica, which contained tetra-coordinated Al, has been investigated through the Surface Organometallic Chemistry (SOMC) methodology. The main interest of this study lies in the peculiarity of the silica supports, which display a well-defined tetrahedral aluminum hydride site displaying a strong Lewis acid character, [( 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 11111111111111111 11111111111111111 00000000000000000 00000000000000000 00000000000000000 00000000000000000 11111111111111111 11111111111111111 00000000000000000 00000000000000000 00000000000000000 00000000000000000 11111111111111111 11111111111111111 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 Si-O-Si 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 11111111111111111 11111111111111111 00000000000000000 00000000000000000 00000000000000000 00000000000000000 11111111111111111 11111111111111111 00000000000000000 00000000000000000 00000000000000000 00000000000000000 11111111111111111 11111111111111111 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 )( 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 11111111111111111 11111111111111111 00000000000000000 00000000000000000 00000000000000000 00000000000000000 11111111111111111 11111111111111111 00000000000000000 00000000000000000 00000000000000000 00000000000000000 11111111111111111 11111111111111111 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 Si-O-)2 Al-H]...
April 14, 2018: Chemical Science
https://www.readbyqxmd.com/read/29779379/phase-segregation-in-potassium-doped-lead-halide-perovskites-from-39k-solid-state-nmr-at-21-1-t
#17
Dominik J Kubicki, Daniel Prochowicz, Albert Hofstetter, Shaik Mohammed Zakeeruddin, Michael Grätzel, Lyndon Emsley
Organic-inorganic lead halide perovskites are a promising family of light absorbers for a new generation of solar cells, with reported efficiencies currently exceeding 22%. A common problem of solar cells fabricated using these materials is that their efficiency depends on their cycling history, an effect known as current-voltage (J-V) hysteresis. Potassium doping has recently emerged as a universal way to overcome this adverse phenomenon. While the atomistic origins of J-V hysteresis are still not fully understood, it is essential to rationalize the atomic-level effect of protocols that lead to its suppression...
May 21, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29775589/better-together-a-hybrid-amyloid-signals-necroptosis
#18
Dan Li, Cong Liu
A new solid-state NMR study determines the high-resolution hetero-amyloid structure of the RIPK1-RIPK3 signaling complex that is involved in mediating necroptosis. The structure demonstrates specific formation of hetero-amyloids over homo-amyloids and the structural basis for a functional amyloid to act as a platform to recruit and activate downstream partners in intracellular signaling.
May 17, 2018: Cell
https://www.readbyqxmd.com/read/29775053/uranyl-tri-bis-silyl-amide-alkali-metal-contact-and-separated-ion-pair-complexes
#19
Philip J Cobb, David J Moulding, Fabrizio Ortu, Simon Randall, Ashley J Wooles, Louise S Natrajan, Stephen T Liddle
We report the preparation of a range of alkali metal uranyl(VI) tri- bis(silyl)amide complexes [{M(THF) x }{(μ-O)U(O)(N″)3 }] (1M) (N″ = {N(SiMe3 )2 }- , M = Li, Na, x = 2; M = K, x = 3; M = K, Rb, Cs, x = 0) containing electrostatic alkali metal uranyl-oxo interactions. Reaction of 1M with 2,2,2-cryptand or 2 equiv of the appropriate crown ether resulted in the isolation of the separated ion pair species [U(O)2 (N″)3 ][M(2,2,2-cryptand)] (3M, M = Li-Cs) and [U(O)2 (N″)3 ][M(crown)2 ] (4M, M = Li, crown = 12-crown-4 ether; M = Na-Cs, crown = 15-crown-5 ether)...
May 18, 2018: Inorganic Chemistry
https://www.readbyqxmd.com/read/29774644/storage-of-co%C3%A2-into-porous-coordination-polymer-controlled-by-molecular-rotor-dynamics
#20
Munehiro Inukai, Masanori Tamura, Satoshi Horike, Masakazu Higuchi, Susumu Kitagawa, Koichi Nakamura
Design to store gas molecules, such as CO₂, H₂, and CH₄, under low pressure is one of the most important challenges in chemistry and materials science. Herein, we describe the storage of CO₂ in the cavities of a porous coordination polymer (PCP) using molecular rotor dynamics. Owing to the narrow pore windows of PCP, CO₂ was not adsorbed at 195 K. As the temperature increased, the rotors exhibited rotational modes; such rotations dynamically expanded the size of the windows, leading to CO₂ adsorption...
May 18, 2018: Angewandte Chemie
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