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https://www.readbyqxmd.com/read/29791041/polymorphism-weak-interactions-and-phase-transitions-in-chalcogen-phosphorus-heterocycles
#1
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/29782148/accelerated-bone-regeneration-by-nitrogen-doped-carbon-dots-functionalized-with-hydroxyapatite-nanoparticles
#2
Deepak Kumar Khajuria, Vijay Bhooshan Kumar, Dana Gigi, Aharon Gedanken, David Karasik
We investigated the osteogenic potential of nitrogen doped carbon dots (NCDs) conjugated with hydroxyapatite (HA) nanoparticles on the MC3T3-E1 osteoblast cell functions and in a zebrafish (ZF) jaw bone regeneration (JBR) model. The NCDs-HA nanoparticles were fabricated by hydrothermal cum co-precipitation technique. The surface structures of NCDs-HA nanoparticles were characterized by XRD, FTIR, UV-Vis, and laser fluorescent spectroscopy, SEM, TEM, EDS, and NMR analysis. The TEM data confirmed that the NCDs are well conjugated on the HA nanoparticle surfaces...
May 21, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29767654/hydrosoluble-cu-i-dapta-complexes-synthesis-characterization-luminescence-thermochromism-and-catalytic-activity-for-microwave-assisted-three-component-azide-alkyne-cycloaddition-click-reaction
#3
Abdallah G Mahmoud, M Fátima C Guedes da Silva, Jerzy Sokolnicki, Piotr Smoleński, Armando J L Pombeiro
New hydrosoluble and air-stable Cu(i) halide compounds, viz. [CuX(DAPTA)3] (1) and (2), and [Cu(μ-X)(DAPTA)2]2 (3) and (4) (X = Br or I, in this order), have been prepared by reacting Cu(i) halide (i.e., bromide or iodide) with 3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane (DAPTA) under mild conditions. They represent the first examples of Cu(i) halide complexes bearing the DAPTA ligand, which have been fully characterized by elemental analysis, IR, 1H, 13C{1H} and 31P{1H} NMR spectroscopies, ESI-MS+ and, for 4, also by single-crystal X-ray diffraction (SCXRD) analyses...
May 16, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/29746124/stereoelectronic-effects-on-the-binding-of-neutral-lewis-bases-to-cdse-nanocrystals
#4
Nicholas C Anderson, Peter E Chen, Aya K Buckley, Jonathan De Roo, Jonathan S Owen
Using 31P nuclear magnetic resonance (NMR) spectroscopy, we monitor the competition between tri-n-butylphosphine (Bu3P) and various amine and phosphine ligands for the surface of chloride terminated CdSe nanocrystals. Distinct 31P NMR signals for free and bound phosphine ligands allow their surface coverages to be directly measured. Ligands with a small steric profile achieve higher surface coverages (Bu3P = 0.5 nm-2, Me2P-n-octyl = 2.0 nm-2, NH2Bu = > 3 nm-2) and have greater relative binding affinity (Krel) for the nanocrystal (Krel: Me3P > Me2P-n-octyl ~ Me2P-n-octadecyl > Et3P > Bu3P)...
May 10, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29736950/hypophosphites-as-eco-compatible-fuel-for-membrane-free-direct-liquid-fuel-cells
#5
Renhe Wang, Mengjia Wu, Servane Haller, Pascal Métivier, Yonggang Wang, Yongyao Xia
Crossover of liquid fuel remains a severe problem for conventional direct liquid fuel cells even when polymer electrolyte membranes are applied. Herein, we report for the first time a membrane-free direct liquid fuel cell powered by alkaline hypophosphite solution. The proof-of-concept fuel cell yields a peak power density of 32 mW cm-2 under air flow at room temperature. The removal of the polymer electrolyte membrane is attributed to the high reactivity and selectivity of Pd and α-MnO2 towards the hypophosphite oxidation on anode and oxygen reduction on the cathode, respectively...
May 7, 2018: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29730667/investigating-muscle-function-after-stroke-rehabilitation-with-31p-mrs-a-preliminary-study
#6
Shuai Zhang, Min Chen, Lei Gao, Ying Liu
BACKGROUND New evidence reveals significant metabolic changes in skeletal muscle after stroke. However, it is unknown if 31P magnetic resonance spectroscopy (31P-MRS) can evaluate these metabolic changes. Our objective here was to investigate: (a) if muscle energy metabolism changes in the affected side; (b) if muscle energy metabolism changes after rehabilitation; and (c) if energy metabolism measured by 31P-MRS can reflect changes in the Modified Modified Ashworth Scale (MMAS) and Fugl-Meyer assessment-lower extremity (FMA-LE) scores after rehabilitation...
May 6, 2018: Medical Science Monitor: International Medical Journal of Experimental and Clinical Research
https://www.readbyqxmd.com/read/29667556/ultrasound-promoted-green-synthesis-docking-study-of-indole-spliced-thiadiazole-%C3%AE-amino-phosphonates-as-anticancer-agents-and-anti-tyrosinase-agents
#7
Anna Pratima G Nikalje, Pramod Gawhane, Shailee Tiwari, Jaiprakash Sangshetti, Manoj Damale
In this work, a new series of diethyl ((1H-indole-3-yl)((5-phenyl-1,3,4-thiadiazole-2- yl)amino)methyl)phosphonate derivatives 6(a-j) were designed and synthesized in Ultrasound by green protocol using Kabachnik-Fields reaction. The structures of the synthesized compounds were confirmed by spectral analysis such as elemental analyses, IR, 1H NMR, 13C NMR, 31P NMR and mass spectra. The synthesized compounds 6(a-j) were appraised for their in vitro anticancer activity against human cancer cell lines such as SK-MEL-2 (melanoma), IMR-32 (Neuroblastoma), HT-29(Colon) and also on normal murine embryonic fibroblast NIH/3T3 by Sulforhodamine B (SRB) assay, using Adriamycin as a standard drug...
April 17, 2018: Anti-cancer Agents in Medicinal Chemistry
https://www.readbyqxmd.com/read/29660195/enantiopure-phospha-1-ferrocenophanes-textbook-examples-for-through-space-nuclear-spin-spin-coupling
#8
Saeid Sadeh, My P T Cao, J Wilson Quail, Jianfeng Zhu, Jens Müller
Three enantiopure phospha[1]ferrocenophanes (2R) equipped with either a phenyl, an isopropyl, or a tert-butyl group at the bridging phosphorus atom were synthesized by a salt-metathesis approach in isolated yields between 52 and 63%. The chirality in these strained sandwich compounds stems from the planar-chiral ferrocene moiety, which is symmetrically equipped with two iPr groups adjacent to phosphorus. Surprisingly, all three phospha[1]ferrocenophanes show an uncommon through-space nuclear 1H-31P coupling...
April 16, 2018: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29644834/31p-mr-spectroscopy-of-patients-with-mild-and-serious-lower-limb-ischemia
#9
Petr Sedivy, Miloslav Drobny, Monika Dezortova, Vit Herynek, Karel Roztocil, Helena Cermakova, Andrea Nemcova, Michal Dubsky, Milan Hajek
BACKGROUND: 31P MR spectroscopy is a technique for undertaking a comprehensive evaluation of muscle metabolism. The goal of this study was to compare patients with mild and severe lower limb ischemia measured by 31P MR spectroscopy at rest and during exercise. METHODS: 16 nondiabetic mild peripheral arterial occlusive disease (PAOD) patients, 23 diabetic PAOD patients with severe ischemia and 19 healthy controls were examined by rest and dynamic 31P MR spectroscopy with a 3T MR system equipped with an MR-compatible home-made pedal ergometer...
April 11, 2018: International Angiology: a Journal of the International Union of Angiology
https://www.readbyqxmd.com/read/29616252/synthesis-structural-characterization-and-transformation-of-an-eight-electron-superatomic-alloy-au-ag-19-s-2-p-opr-2-12
#10
Yan-Ru Lin, Pilli V V N Kishore, Jian-Hong Liao, Samia Kahlal, Yu-Chiao Liu, Ming-Hsi Chiang, Jean-Yves Saillard, C W Liu
Controlling the metal nanoclusters with atomic precision is highly difficult and further studies on their transformation reactions are even more challenging. Herein we report the controlled formation of a silver alloy nanocluster [AuAg19{S2P(OnPr)2}12] (1) from an Ag20 template via a galvanic exchange route. X-ray structural analysis reveals that the alloy structure comprises of a gold-centered Ag12 icosahedron, Au@Ag12, capped by seven silver atoms. Interestingly upon reacting with one equiv. of silver(i) salt, (1) can transform into a higher nuclearity nanocluster, [Au@Ag20{S2P(OnPr)2}12]+ (2)...
April 4, 2018: Nanoscale
https://www.readbyqxmd.com/read/29589933/structural-characterization-of-biocompatible-reverse-micelles-using-small-angle-x-ray-scattering-31-p-nuclear-magnetic-resonance-and-fluorescence-spectroscopy
#11
Emmanuel Odella, Ruben Dario Falcone, Marcelo Ceolin, Juana J Silber, N Mariano Correa
The most critical problem regarding the use of reverse micelles (RMs) in several fields is the toxicity of their partial components. In this sense, many efforts have been made to characterize non-toxic RMs formulations based on biological amphiphiles and/or different oils. In this contribution, the microstructure of biocompatible mixed RMs formulated by sodium 1,4-bis-2-ethylhexylsulfosuccinate (AOT) and tri-n-octylphosphine oxide (TOPO) surfactants dispersed in the friendly solvent methyl laurate was studied by using SAXS, 31P NMR and, following the solvatochromic behavior of the molecular probe 4-aminophthalimide (4-AP)...
March 28, 2018: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/29575317/measuring-spin-relaxation-rates-using-satellite-exchange-nmr-spectroscopy
#12
Gerard P Robertson, Barbara Odell, Ilya Kuprov, Darren J Dixon, Tim David Claridge
An approach to the indirect measurement of nuclear spin relaxation rates of low-magnetogyric ratio (γ) nuclei using the process of satellite exchange is described. The method does not require the observation of, or even the ability to provide radio-frequency pulses to, the low-γ nucleus, but requires this to be scalar coupled to an NMR observable nucleus, such as 31P or 1H, making it especially attractive for the study of diamagnetic transition metals. In situations where spin relaxation is dominated by chemical shift anisotropy (CSA), the determination of the longitudinal spin relaxation time constant (T1) of the metal becomes possible, as illustrated for 195Pt and 107/109Ag...
March 25, 2018: Angewandte Chemie
https://www.readbyqxmd.com/read/29557170/substantial-decrease-in-plasmalogen-in-the-heart-associated-with-tafazzin-deficiency
#13
Tomohiro Kimura, Atsuko K Kimura, Mindong Ren, Bob Berno, Yang Xu, Michael Schlame, Richard M Epand
Tafazzin is the mitochondrial enzyme that catalyzes transacylation between a phospholipid and a lysophospholipid in remodeling. Mutations in tafazzin cause Barth syndrome, a potentially life-threatening disease with the major symptom being cardiomyopathy. In the tafazzin-deficient heart, cardiolipin (CL) acyl chains become abnormally heterogeneous unlike those in the normal heart with a single dominant linoleoyl species, tetralinoleoyl CL. In addition, the amount of CL decreases and monolysocardiolipin (MLCL) accumulates...
April 10, 2018: Biochemistry
https://www.readbyqxmd.com/read/29546906/cobalt-complexes-of-biginelli-derivatives-as-fluorescent-probes-for-selective-estimation-and-degradation-of-organophosphates-in-aqueous-medium
#14
Gaganpreet Kaur, Amanpreet Singh, Ajnesh Singh, Navneet Kaur, Narinder Singh
The unregulated use of organophosphates (OPs) as pesticides and toxic chemical warfare agents demands their continuous monitoring from a human health perspective. This study describes a fluorescence turn-on sensing assay for the selective quantification of OPs in aqueous medium. Metal complexes of two different Biginelli derivatives were processed in water through a reprecipitation technique. The engineered self-assembly of the pyridyl-2-cobalt complex (L1·Co(II)) was employed to selectively detect malathion while the pyridyl-4-cobalt complex (L2·Co(II)) could estimate azamethiphos fluorimetrically up to a detection limit of 9...
April 24, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/29533492/synthesis-and-identification-of-aryl-and-alkyl-gem-dilithium-phosphido-boranes-a-boost-to-the-chemistry-of-phosphandiides
#15
Jie Guang, Romain Duwald, Jacques Maddaluno, Hassan Oulyadi, Sami Lakhdar, Annie-Claude Gaumont, Anne Harrison-Marchand
The synthesis and identification of unprecedented gem-dianionic phosphorus compounds, that is, gem-dilithium phosphido-boranes Li2 [RP⋅BH3 ], with R=Ph or Cy, are reported in THF solution. These were obtained by double deprotonation of the corresponding primary phosphine-borane precursors RPH2 ⋅BH3 . Their in-depth structural study, based on multinuclear (1 H, 6 Li, 7 Li, 11 B, 13 C, 31 P) mono- and bi-dimensional NMR analyses, indicates a strong influence of the phosphorus substituent on the structure of the gem-dianionic phosphorus structure; a monomeric arrangement was obtained when R=phenyl, whereas a cyclic oligomer was observed for R=cyclohexyl...
May 7, 2018: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29522325/a-rational-design-of-highly-controlled-suzuki-miyaura-catalyst-transfer-polycondensation-for-precision-synthesis-of-polythiophenes-and-their-block-copolymers-marriage-of-palladacycle-precatalysts-with-mida-boronates
#16
Kyeong-Bae Seo, In-Hwan Lee, Jaeho Lee, Inho Choi, Tae-Lim Choi
Herein, we report a highly efficient Suzuki-Miyaura catalyst-transfer polycondensation (SCTP) of 3-alkylthiophenes using bench-stable but highly active Buchwald dialkylbiarylphospine Pd G3 precatalysts and N-methylimidodiacetic (MIDA)-boronate monomers. Initially, the feasibility of the catalyst-transfer process was examined by screening various dialkylbiarylphospine-Pd(0) species. After optimizing a small molecule model reaction, we identified both RuPhos and SPhos Pd G3 precatalysts as excellent catalyst systems for this purpose...
March 28, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29521092/designed-synthesis-of-mesoporous-solid-supported-lewis-acid-base-pairs-and-their-co-2-adsorption-behaviors
#17
Maria V Zakharova, Nima Masoumifard, Yimu Hu, Jongho Han, Freddy Kleitz, Frédéric-Georges Fontaine
Conventional amines and phosphines, such as diethylenetriamine, diphenylpropylphosphine, triethylamine, and tetramethylpiperidine, were grafted or impregnated on the surface of metalated SBA-15 materials, such as Ti-, Al-, and Zr-SBA-15, to generate air-stable solid-supported Lewis acid-base pairs. The Lewis acidity of the metalated materials before and after the introduction of Lewis bases was verified by means of pyridine adsorption-Fourier transform infrared spectroscopy. Detailed characterization of the materials was achieved by solid-state 13 C and 31 P MAS NMR spectroscopy, low-temperature N2 physisorption, X-ray photoelectron spectroscopy, and energy-dispersive X-ray mapping analyses...
April 18, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29513536/quantum-chemical-approach-to-nmr-chemical-shifts-in-paramagnetic-solids-applied-to-lifepo-4-and-licopo-4
#18
Arobendo Mondal, Martin Kaupp
A novel protocol to compute and analyze NMR chemical shifts for extended paramagnetic solids, accounting comprehensively for Fermi-contact (FC), pseudocontact (PC), and orbital shifts, is reported and applied to the important lithium ion battery cathode materials LiFePO4 and LiCoPO4 . Using an EPR-parameter-based ansatz, the approach combines periodic (hybrid) DFT computation of hyperfine and orbital-shielding tensors with an incremental cluster model for g- and zero-field-splitting (ZFS) D-tensors. The cluster model allows the use of advanced multireference wave function methods (such as CASSCF or NEVPT2)...
April 5, 2018: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/29498848/tunable-thermosetting-epoxies-based-on-fractionated-and-well-characterized-lignins
#19
Claudio Gioia, Giada Lo Re, Martin Lawoko, Lars Berglund
Here we report the synthesis of thermosetting resins from low molar mass Kraft lignin fractions of high functionality, refined by solvent extraction. Such fractions were fully characterized by 31 P NMR, 2D-HSQC NMR, SEC, and DSC in order to obtain a detailed description of the structures. Reactive oxirane moieties were introduced on the lignin backbone under mild reaction conditions and quantified by simple 1 H NMR analysis. The modified fractions were chemically cross-linked with a flexible polyether diamine ( Mn ≈ 2000), in order to obtain epoxy thermosets...
March 21, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29498505/molecular-engineered-safer-organic-battery-through-the-incorporation-of-flame-retarding-organophosphonate-moiety
#20
Hyun Ho Lee, Dongsik Nam, Choon-Ki Kim, Koeun Kim, Yongwon Lee, Young Jun Ahn, Jae Bin Lee, Ja Hun Kwak, Wonyoung Choe, Nam-Soon Choi, Sung You Hong
Here, we report the first electrochemical assessment of organophosphonate-based compound as a safe electrode material for lithium-ion batteries, which highlights the reversible redox activity and inherent flame retarding property. Dinickel 1,4-benzenediphosphonate delivers a high reversible capacity of 585 mA h g-1 with stable cycle performance. It expands the scope of organic batteries, which have been mainly dominated by the organic carbonyl family to date. The redox chemistry is elucidated by X-ray absorption spectroscopy and solid-state 31 P NMR investigations...
March 28, 2018: ACS Applied Materials & Interfaces
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