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https://www.readbyqxmd.com/read/28941414/synthesis-spectral-and-luminescence-study-crystal-structure-determination-and-dft-calculation-of-binuclear-palladium-ii-complexes
#1
S Seyfi, R Alizadeh, M Darvish Ganji, V Amani
Binuclear palladium(II) complexes with metal-metal (d(8)-d(8)) bonding interaction were synthesized by reactions of the 1-methyl-1H-1,2,3,4-tetrazole-5-thiol (Hmtzt) or a mixture of Hmtzt and 1,3-propanediamine (1,3-pda) ligands. Complex [Pd2(μ-mtzt)4]·2CH3CN (1) was synthesized by the reaction of Pd(OAc)2 with Hmtzt dissolved in acetonitrile and complex [Pd2(μ-mtzt)2(mtzt)2(1,3-pda)] (2) was synthesized by reaction of a mixture of Hmtzt and 1,3-propanediamine (dissolved in methanol) with PdCl2 (dissolved in acetonitrile) and were identified through elemental analysis, IR, UV-Vis, (1)H NMR, luminescence spectroscopy as well as single-crystal X-ray diffraction method...
September 14, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28939533/comparative-mapping-of-on-targets-and-off-targets-for-the-discovery-of-anti-trypanosomatid-folate-pathway-inhibitors
#2
Joanna Panecka-Hofman, Ina Pöhner, Francesca Spyrakis, Talia Zeppelin, Flavio Di Pisa, Lucia Dello Iacono, Alessio Bonucci, Antonio Quotadamo, Alberto Venturelli, Stefano Mangani, Maria Paola Costi, Rebecca C Wade
BACKGROUND: Multi-target approaches are necessary to properly analyze or modify the function of a biochemical pathway or a protein family. An example of such a problem is the repurposing of the known human anti-cancer drugs, antifolates, as selective anti-parasitic agents. This requires considering a set of experimentally validated protein targets in the folate pathway of major pathogenic trypanosomatid parasites and humans: (i) the primary parasite on-targets: pteridine reductase 1 (PTR1) (absent in humans) and bifunctional dihydrofolate reductase-thymidylate synthase (DHFR-TS), (ii) the primary off-targets: human DHFR and TS, and (iii) the secondary on-target: human folate receptor β, a folate/antifolate transporter...
September 20, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28938642/facile-total-synthesis-of-lysicamine-and-the-anticancer-activities-of-the-ru-ii-rh-iii-mn-ii-and-zn-ii-complexes-of-lysicamine
#3
Jiao-Lan Qin, Ting Meng, Zhen-Feng Chen, Xiao-Li Xie, Qi-Pin Qin, Xiao-Ju He, Ke-Bin Huang, Hong Liang
Lysicamine is a natural oxoaporphine alkaloid, which isolated from traditional Chinese medicine (TCM) herbs and has been shown to possess cytotoxicity to hepatocarcinoma cell lines. Reports on its antitumor activity are scarce because lysicamine occurs in plants at a low content. In this work, we demonstrate a facile concise total synthesis of lysicamine from simple raw materials under mild reaction conditions, and the preparation of the Ru(II), Rh(III), Mn(II) and Zn(II) complexes 1-4 of lysicamine (LY). All the compounds were fully characterized by elemental analysis, IR, ESI-MS, (1)H and (13)C NMR, as well as single-crystal X-ray diffraction analysis...
August 29, 2017: Oncotarget
https://www.readbyqxmd.com/read/28938138/continued-sar-exploration-of-1-2-4-thiadiazole-containing-scaffolds-in%C3%A2-the-design-of-free-fatty-acid-receptor-1-gpr40-agonists
#4
Mikhail Krasavin, Alexei Lukin, Anna Bakholdina, Nikolay Zhurilo, Oleksandra Onopchenko, Petro Borysko, Sergey Zozulya, Daniel Moore, Irina G Tikhonova
An earlier reported series of 1,2,4-thiadiazole-based agonists of FFA1 (GPR40) was evolved into two structurally distinct series of compounds. One of the series (structurally related to known FFA1 agonist GW9508) displayed low micromolar potency while the other (representing a truncated version of the earlier reported potent FFA1 agonists) was, surprisingly, found to be devoid of agonist potency. In silico docking of representative compounds into the crystal structure of FFA1 revealed possible structural grounds for the observed SAR...
September 13, 2017: European Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/28938074/native-electron-capture-dissociation-maps-to-iron-binding-channels-in-horse-spleen-ferritin
#5
Owen S Skinner, Michael O McAnally, Richard P Van Duyne, George C Schatz, Kathrin Breuker, Philip D Compton, Neil L Kelleher
Native electron capture dissociation (NECD) is a process during which proteins undergo fragmentation similar to that from radical dissociation methods, but without the addition of exogenous electrons. However, after three initial reports of NECD from the cytochrome c dimer complex, no further evidence of the effect has been published. Here, we report NECD behavior from horse spleen ferritin, a ~490 kDa protein complex ~20-fold larger than the previously studied cytochrome c dimer. Application of front-end infrared excitation (FIRE) in conjunction with low- and high-m/z quadrupole isolation and collisionally activated dissociation (CAD) provides new insights into the NECD mechanism...
September 22, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28937994/modeling-of-annexin-a2-membrane-interactions-by-molecular-dynamics-simulations
#6
Davit Hakobyan, Volker Gerke, Andreas Heuer
The annexins are a family of Ca2+-regulated phospholipid binding proteins that are involved in membrane domain organization and membrane trafficking. Although they are widely studied and crystal structures are available for several soluble annexins their mode of membrane association has never been studied at the molecular level. Here we obtained molecular information on the annexin-membrane interaction that could serve as paradigm for the peripheral membrane association of cytosolic proteins by Molecular Dynamics simulations...
2017: PloS One
https://www.readbyqxmd.com/read/28937933/what-s-in-a-name-correlates-of-ecstasy-users-knowing-or-agreeing-that-molly-is-ecstasy-mdma
#7
Joseph J Palamar
Ecstasy (MDMA) has regained popularity in powder and crystalline form, known as Molly. However, it is unknown whether all Molly users are aware that Molly is ecstasy. A total of 1045 nightclub/festival-attending adults in New York City were surveyed about ecstasy/MDMA/Molly use in 2016. Users were asked if they agreed that "Molly is (or is supposed to be) ecstasy/MDMA." Of the 43.5% reporting lifetime use, 84.6% agreed that Molly is ecstasy, 9.5% disagreed, and 5.9% reported not knowing that Molly is ecstasy...
September 22, 2017: Journal of Psychoactive Drugs
https://www.readbyqxmd.com/read/28937776/4-c-methoxy-2-deoxy-2-fluoro-modified-ribonucleotides-improve-metabolic-stability-and-elicit-efficient-rnai-mediated-gene-silencing
#8
Elise Malek-Adamian, Dale Guenther, Shigeo Matsuda, Saúl Martínez-Montero, Ivan Zlatev, Joel Harp, Mihai Burai Patrascu, Donald J Foster, Johans J Fakhoury, Lydia Perkins, Nicolas Moitessier, Rajar Manoharan, Nate Taneja, Anna Bisbe, Klaus Charisse, Martin A Maier, Kallanthottathil G Rajeev, Martin Egli, Muthiah Manoharan, Masad J Damha
We designed novel 4'-modified 2'-deoxy-2'-fluorouridine (2'-F U) analogues with the aim to improve nuclease resistance and potency of therapeutic siRNAs by introducing 4'-C-methoxy (4'-OMe) as the alpha (C4'α) or beta (C4'β) epimers. The C4'α epimer was synthesized by a stereoselective route in six steps; however, both α and β epimers could be obtained by a non-stereoselective approach starting from 2'-F U. (1)H-NMR analysis and computational investigation of the α-epimer revealed that the 4'-OMe imparts a conformational bias towards the North-East sugar pucker, due to intramolecular hydrogen bonding and hyperconjugation effects...
September 22, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28937766/approach-toward-the-understanding-of-coupling-mechanism-for-edc-reagent-in-solvent-free-mechanosynthesis
#9
Aneta Wróblewska, Piotr Paluch, Ewelina Wielgus, Grzegorz Bujacz, Marta K Dudek, Marek J Potrzebowski
A unique approach in mechanosynthesis, joining solid-state NMR spectroscopy, X-ray crystallography, and theoretical calculations, is employed for the first time to study the mechanism of the formation of the C-N amide bond using EDC·HCl as a coupling reagent. It has been proved that EDC·HCl, which in the crystal lattice exists exclusively in the cyclic form (X-ray data), easily undergoes transformation to a pseudocyclic stable intermediate in reaction with carboxylic acid forming a low-melt phase (differential scanning calorimetry, solid-state NMR)...
September 22, 2017: Organic Letters
https://www.readbyqxmd.com/read/28937765/origin-of-substitution-mechanism-for-the-binding-of-organic-ligands-on-the-surface-of-cspbbr3-perovskite-nanocubes
#10
Vikash Kumar Ravi, Pralay K Santra, Niharika Joshi, Jeetender Chugh, Sachin Kumar Singh, Håkan Rensmo, Prasenjit Ghosh, Angshuman Nag
Optoelectronic properties of CsPbBr3 perovskite nanocubes (NCs) depend strongly on the interaction of the organic passivating molecules with the inorganic crystal. To understand this interaction, we employed a combination of synchrotron-based X-ray photoelectron spectroscopy (XPS), nuclear magnetic resonance (NMR) spectroscopy and first principles density functional theory (DFT) based calculations. XPS elucidated the internal structure of inorganic part in a layer-by-layer fashion, whereas, NMR characterized the organic ligands...
September 22, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28937763/hybrid-cis-trans-tetra-arylethenes-with-switchable-aie-and-reversible-photochromism-in-the-solution-pmma-film-solid-powder-and-single-crystal
#11
Qianfu Luo, Fei Cao, Chaochao Xiong, Qingyu Dou, Da-Hui Qu
How to efficiently design and synthesize multifunctional molecules is particularly challenging. Here we devote to constructing a kind of simple structures with composite functionalities through straightforward preparation. Starting from common commercially available materials, the titled cis/ tans-tetraarylethenes can be conveniently obtained by one-pot under mild conditions. The different configurations were confirmed by 1H NMR and single crystal data analysis. The trans-tetraarylethenes could be converted into cis-forms not only by photo-irradiation but also by microwave irradiation, which provided us a new choice for isomeric conversion, especially for which sensitive to light...
September 22, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28937756/direct-comparison-of-c-h-bond-amination-efficacy-through-manipulation-of-nitrogen-valence-centered-redox-imido-versus-iminyl
#12
Matthew J T Wilding, Diana A Iovan, Alexandra T Wrobel, James T Lukens, Samantha N MacMillan, Kyle M Lancaster, Theodore A Betley
Reduction of previously reported iminyl radical (ArL)FeCl(•N(C6H4-p-tBu)) (2) with potassium graphite furnished the corresponding high-spin (S = 5/2) imido (ArL)Fe(N(C6H4-p-tBu)) (3) (ArL = 5-mesityl-1,9-(2,4,6-Ph3C6H2)dipyrrin). Oxidation of the three-coordinate imido (ArL)Fe(NAd) (5) with chlorotriphenylmethane afforded (ArL)FeCl(•NAd) (6) with concomitant expulsion of Ph3C(C6H5)CPh2. The respective alkyl/aryl imido/iminyl pairs (3, 2; 5, 6) have been characterized by EPR, zero-field 57Fe Mössbauer, magnetometry, single crystal X-ray diffraction, XAS, and EXAFS for 6...
September 22, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28937755/stability-and-superconductivity-of-k-p-compounds-under-pressure
#13
Yunxian Liu, Chao Wang, Xiangmu Kong, Defang Duan
We explore the phase diagram, structures, electron properties, and potential superconductivity of the K-P system at pressures of up to 200 GPa through unbiased structure searching techniques and first-principles calculations. Five stable chemical stoichiometries (K4P, K3P, K2P, KP, and KP2) have been theoretically predicted. In particular, P2 units or P-chains are uncovered in K2P, KP, and KP2 compounds with the existence of covalent bonds by analyzing the electron localization functions. And the Bader analysis demonstrates that charges transfer from K atoms to P atoms...
September 22, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28937753/facile-substitution-of-bridging-so2-2-ligands-in-re12-bioctahedral-cluster-complexes
#14
Yakov M Gayfulin, Anton I Smolentsev, Svetlana G Kozlova, Igor N Novozhilov, Pavel E Plyusnin, Nikolay B Kompankov, Yuri V Mironov
Selective substitution of μ-SO2(2-) groups by either O(2-) or Se(2-) ions occurs upon heating the bioctahedral rhenium cluster complex K6[Re12CS14(μ-SO2)3(CN)6] in air atmosphere or in the presence of a Se source, respectively, manifesting the remarkable lability of SO2(2-) ligands bound to a transition-metal cluster. A series of compounds based on the new mixed-ligand anions, [Re12CS14(μ-O)3(CN)6](6-), [Re12CS14(μ-Se)3(CN)6](6-), and [Re12CS14(μ-O)3(OH)6](6-), were isolated and their solid-state structures were elucidated by single-crystal X-ray diffraction analysis...
September 22, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28937749/heterooctamolybdate-based-clusters-h3-cp-rh-4pmo8o32-and-h5-na2-cp-ir-4pmo8o34-and-derived-hybrid-nanomaterials-with-efficient-electrocatalytic-hydrogen-evolution-reaction-activity
#15
Vikram Singh, Pengtao Ma, Michael G B Drew, Jingyang Niu, Jingping Wang, Guo-Xin Jin
Polyoxometalates (POMs), emerging as a new class of porous molecular materials, play a promising role in homo- and heterogeneous catalysis. Among them, noble-metal-decorated POMs have a profound impact as catalytic materials. Thus, it is imperative to design and structurally explore new catalysts including noble metals. Herein, two new clusters, H3[(Cp*Rh)4PMo8O32]·14H2O (1) and H5[Na2(Cp*Ir)4PMo8O34]·13H2O (2) (Cp* = pentamethylcyclopentadienyl), based on a heterooctamolybdate anionic core were successfully obtained via a one-pot reaction using [Cp*MCl2]2 [M = Rh (1) and Ir (2)] and Na2MoO4 in acidic conditions...
September 22, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28937745/mononuclear-fe-ii-complexes-based-on-the-methylpyrazinyl-diamine-ligand-chemical-thermo-and-photocontrol-of-their-magnetic-switchability
#16
Xue Liu, Jian Zhou, Xin Bao, Zheng Yan, Guo Peng, Mathieu Rouzières, Corine Mathonière, Jun-Liang Liu, Rodolphe Clérac
Two new mononuclear Fe(II) complexes, [Fe((2Me)Lpz)(NCX)2] (L = N,N'-dimethyl-N,N'-bis((pyrazin-2-yl)methyl)-1,2-ethanediamine and X = S (1), BH3 (2)), have been synthesized and characterized by single-crystal X-ray diffraction, magnetic, optical reflectivity, and photomagnetic measurements. They have similar FeN6 coordination environments offered by the tetradentate ligand with a cis-α conformation and two NCX(-) coligands in cis positions. However, 1 and 2 have different molecular arrangements and crystal packings, and are isolated in orthorhombic Pbnb and monoclinic C2/c space groups, respectively...
September 22, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28937695/trinuclear-complexes-of-palladium-ii-with-chalcogenated-n-heterocyclic-carbenes-catalysis-of-selective-nitrile-primary-amide-interconversion-and-sonogashira-coupling
#17
Pooja Dubey, Sonu Gupta, Ajai K Singh
3-Methyl-1-(2-(phenylthio/seleno)ethyl)-1H-benzo[d]imidazol-3-ium iodide (L1/L2), a precursor of sulfated/selenated N-heterocyclic carbene, was synthesized by the reaction of benzimidazole with 1,2-dichloroethane followed by treatment with PhS/SeNa and MeI. The reaction of L1/L2 with Ag2O followed by treatment with [Pd(CH3CN)2Cl2] (metal to ligand ratio 3 : 2), i.e. transmetallation, resulted in trinuclear palladium(ii) complexes [Pd3(L1/L2-HI)2(CH3CN)Cl6] (1-2). The complexes were characterized with (1)H, (13)C{(1)H} and (77)Se{(1)H} NMR (2 only), elemental analyses, HR-MS and single-crystal X-ray diffraction...
September 22, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28937678/anionic-silicate-organic-frameworks-constructed-from-hexacoordinate-silicon-centres
#18
Jérôme Roeser, Dragica Prill, Michael J Bojdys, Pierre Fayon, Abbie Trewin, Andrew N Fitch, Martin U Schmidt, Arne Thomas
Crystalline frameworks composed of hexacoordinate silicon species have thus far only been observed in a few high pressure silicate phases. By implementing reversible Si-O chemistry for the crystallization of covalent organic frameworks, we demonstrate the simple one-pot synthesis of silicate organic frameworks based on octahedral dianionic SiO6 building units. Clear evidence of the hexacoordinate environment around the silicon atoms is given by (29)Si nuclear magnetic resonance analysis. Characterization by high-resolution powder X-ray diffraction, density functional theory calculation and analysis of the pair-distribution function showed that those anionic frameworks-M2[Si(C16H10O4)1...
October 2017: Nature Chemistry
https://www.readbyqxmd.com/read/28937675/coherent-singlet-fission-activated-by-symmetry-breaking
#19
Kiyoshi Miyata, Yuki Kurashige, Kazuya Watanabe, Toshiki Sugimoto, Shota Takahashi, Shunsuke Tanaka, Jun Takeya, Takeshi Yanai, Yoshiyasu Matsumoto
Singlet fission, in which a singlet exciton is converted to two triplet excitons, is a process that could be beneficial in photovoltaic applications. A full understanding of the dynamics of singlet fission in molecular systems requires detailed knowledge of the relevant potential energy surfaces and their (conical) intersections. However, obtaining such information is a nontrivial task, particularly for molecular aggregates. Here we investigate singlet fission in rubrene crystals using transient absorption spectroscopy and state-of-the-art quantum chemical calculations...
October 2017: Nature Chemistry
https://www.readbyqxmd.com/read/28937665/a-reductive-aminase-from-aspergillus-oryzae
#20
Godwin A Aleku, Scott P France, Henry Man, Juan Mangas-Sanchez, Sarah L Montgomery, Mahima Sharma, Friedemann Leipold, Shahed Hussain, Gideon Grogan, Nicholas J Turner
Reductive amination is one of the most important methods for the synthesis of chiral amines. Here we report the discovery of an NADP(H)-dependent reductive aminase from Aspergillus oryzae (AspRedAm, Uniprot code Q2TW47) that can catalyse the reductive coupling of a broad set of carbonyl compounds with a variety of primary and secondary amines with up to >98% conversion and with up to >98% enantiomeric excess. In cases where both carbonyl and amine show high reactivity, it is possible to employ a 1:1 ratio of the substrates, forming amine products with up to 94% conversion...
October 2017: Nature Chemistry
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