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Metal Complexes

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https://read.qxmd.com/read/30901691/role-of-apoplastic-calcium-during-germination-and-initial-stages-of-seedling-establishment-in-vigna-radiata-seeds
#1
Giti Verma, Sadaf Khan, Sudhir Kumar Agarwal, Samir Sharma
Calcium (Ca2+ ) is implicated in the initial phase of seed germination and seedling establishment. It is stored complexed with phytic acid during seed development and released by phytase action during germination. We observed phytase activity 18 h post-imbibition (PI) in Vigna seeds, while radicle protrusion occurred approximately 12 h PI. Cotyledon protein extracts prepared 4, 8, 16 and 24 h PI, subjected to Ca2+ immobilized metal affinity chromatography (Ca2+ IMAC), revealed the presence of Ca2+ binding proteins (CaBPs), while Ca2+ -dependent amylase activity peaked 18 h PI, implying Ca2+ presence before its release from Ca-phytate, indicating an alternative source of Ca2+ ...
February 28, 2019: Journal of Plant Physiology
https://read.qxmd.com/read/30901684/comparative-studies-on-pb-ii-biosorption-with-three-spongy-microbe-based-biosorbents-high-performance-selectivity-and-application
#2
Nana Wang, Yuyin Qiu, Tangfu Xiao, Jianqiao Wang, Yuxiao Chen, Xingjian Xu, Zhichao Kang, Lili Fan, Hongwen Yu
Lead pollution in industrial-derived water has become an increasingly serious concern. The development of adsorbents with excellent efficiency, selectivity and separability using diverse microorganisms is ideal for treating lead pollution. In this study, gram-negative bacteria Pseudomonas putida I3, gram-positive bacteria Microbacterium sp. OLJ1 and mycelial fungus Talaromyces amestolkiae Pb served as raw materials to facilely synthesize sponge-like biosorbents via a one-step method at room temperature. SEM, EDS, FTIR, 13 C NMR, XRD and XPS were used for investigating the morphology and surface properties of these three biosorbents...
March 15, 2019: Journal of Hazardous Materials
https://read.qxmd.com/read/30901655/zn-overaccumulating-russula-species-clade-together-and-use-the-same-mechanism-for-the-detoxification-of-excess-zn
#3
Tereza Leonhardt, Jan Borovička, Jan Sácký, Jiří Šantrůček, Jan Kameník, Pavel Kotrba
It has been firmly established that macrofungi can accumulate large amounts of heavy metals in their sporocarps. However, the mechanisms of the accumulation and storage are being uncovered only recently. We have previously documented that Russula bresadolae can accumulate over 1 g Zn kg-1 dry weight and that sequestration of a substantial proportion of overaccumulated Zn involves binding with peptides, RaZBPs, seen so far only in this species. In this work we examined Zn contents of 360 sporocarp collections from unpolluted environments covering 114 species of the genus Russula...
March 12, 2019: Chemosphere
https://read.qxmd.com/read/30901626/the-osmotic-effect-of-hyper-saline-hydraulic-fracturing-fluid-on-rainbow-trout-oncorhynchus-mykiss
#4
P L M Delompré, T A Blewett, K N Snihur, S L Flynn, D S Alessi, C N Glover, G G Goss
Flowback and produced water (FPW) is a complex, often brackish, solution formed during the process of hydraulic fracturing. Despite recent findings on the short-term toxicity of FPW on aquatic biota, longer-term impacts of FPW on fish have not yet been investigated and the mechanisms of chronic effects remain unknown. The aim of the present study was to observe the effect of a diluted FPW on ionoregulatory endpoints in the rainbow trout Oncorhynchus mykiss, following a 28-d sub-chronic exposure. A salinity-matched control solution (SW), recreating the salt content of the FPW, was used to differentiate the specific effect of the salts from the effects of the other FPW components (i...
March 14, 2019: Aquatic Toxicology
https://read.qxmd.com/read/30901511/validating-the-biphilic-hypothesis-of-nontrigonal-p-iii-compounds
#5
Kyounghoon Lee, Anastasia Blake, Akira Tanushi, Sean McCarthy, Daniel Kim, Sydney Loria, Courtney Donahue, Kyle Spielvogel, Jason Keith, Scott Daly, Alexander T Radosevich
Constraining σ3-P compounds in nontrigonal, entatic geometries has proven to be an effective strategy for promoting biphilic oxidative addition reactions more typical of transition metals. Although qualitative descriptions of the impact of structure and symmetry on σ3-P complexes have been proposed, electronic structure variations responsible for biphilic reactivity have yet to be elucidated experimentally. Here we report P K-edge XANES data and complementary TDDFT calculations for a series of structurally-modified P(N)3 complexes that both validate and quantify electronic structure variations proposed to give rise to biphilic reactions at phosphorus...
March 22, 2019: Angewandte Chemie
https://read.qxmd.com/read/30901228/pyridazine-n-oxides-as-precursors-to-2-aminofurans-scope-and-limitations-in-complexity-building-cascade-reactions
#6
Maribel Borger, James H Frederich
A method to transform pyridazine N-oxides into 2-aminofurans using a combination of UV light and transition metal catalysis has been developed. These electron-rich species exhibit a surprising range of useful reactivity, including the ability to participate in complexity building cascade processes when reacted with dienophiles. This study also establishes 2-aminofurans as valuable synthons that support modular synthetic entry to the shared heterocyclic core of certain aspidosperma and amaryllidaceae alkaloids...
March 22, 2019: Organic Letters
https://read.qxmd.com/read/30901216/chiral-cyclopentadienyl-cobalt-iii-complexes-enable-highly-enantioselective-3d-metal-catalyzed-c-h-functionalizations
#7
Kristers Ozols, Yun-Suk Jang, Nicolai Cramer
The synthesis of a set of cobalt(III)-complexes equipped with trisubstituted chiral cyclopentadienyl ligands is reported and their steric and electronic parameters are mapped. The application potential of these complexes for asymmetric C-H functionalizations with 3d-metals is shown by the synthesis of dihydroisoquinolones from N-chlorobenzamides with a broad range of alkenes. The transformation proceeds with excellent enantioselectivities of up to 99.5:0.5 er and high regioselectivities. The observed values outperform the best rhodium(III)-based methods for this reaction type...
March 22, 2019: Journal of the American Chemical Society
https://read.qxmd.com/read/30901200/control-by-metals-of-staphylopine-dehydrogenase-activity-during-metallophore-biosynthesis
#8
Christine Hajjar, Roberto Fanelli, Clémentine Laffont, Catherine Brutesco, Gregorio Cullia, Mathilde Tribout, Didier Nurizzo, Elise Borezée-Durant, Romé Voulhoux, David Pignol, Jérôme Lavergne, Florine Cavelier, Pascal Arnoux
Enzymatic regulations are central processes for the adaptation to changing environments. In the particular case of metallophore-dependent metal uptake, there is a need to quickly adjust the production of these metallophores to the metal level outside the cell, to avoid metal shortage or overload, as well as waste of metallophores. In Staphylococcus aureus, CntM catalyzes the last biosynthetic step in the production of staphylopine, a broad-spectrum metallophore, through the reductive condensation of a pathway intermediate (xNA) with pyruvate...
March 22, 2019: Journal of the American Chemical Society
https://read.qxmd.com/read/30901122/luminescent-rhenium-i-polypyridine-complexes-appended-with-a-perylene-diimide-or-benzoperylene-monoimide-moiety-photophysics-intracellular-sensing-and-photocytotoxic-activity
#9
Alex Man-Hei Yip, Justin Shum, Hua-Wei Liu, Huipeng Zhou, Meiqi Jia, Niu Niu, Yongxin Li, Cong Yu, Kenneth Kam-Wing Lo
This communication reports novel luminescent rhenium(I) polypyridine complexes appended with a perylene diimide (PDI) or benzoperylene monoimide (BPMI) moiety via a non-conjugated linker. The photophysical and photochemical properties originating from the interactions of the metal polypyridine and perylene units were exploited to afford new cellular reagents with thiol-sensing capability and excellent photocytotoxic activity.
March 22, 2019: Chemistry: a European Journal
https://read.qxmd.com/read/30900885/electrophilic-organoiridium-iii-pincer-complexes-on-sulfated-zirconia-for-hydrocarbon-activation-and-functionalization
#10
Zoha Syed, David Kaphan, Frédéric A Perras, Marek Pruski, Magali S Ferrandon, Evan C Wegener, Gokhan Celik, Jianguo Wen, Cong Liu, Fulya Dogan, Karen I Goldberg, Massimiliano Delferro
Single-site supported organometallic catalysts bring together the favorable aspects of homogeneous and heterogeneous ca-talysis while offering opportunities to investigate the impact of metal-support interactions on reactivity. We report a (dmPhebox)Ir(III) (dmPhebox = 2,6-bis(4,4-dimethyloxazolinyl)-3,5-dimethylphenyl) complex chemisorbed on sulfated zirco-nia, the molecular precursor for which was previously applied to hydrocarbon functionalization. Spectroscopic methods such as diffuse reflectance infrared Fourier transformation spectroscopy (DRIFTS), dynamic nuclear polarization (DNP)-enhanced solid-state nuclear magnetic resonance (SSNMR) spectroscopy, and X-ray absorption spectroscopy (XAS) were used to characterize the supported species...
March 22, 2019: Journal of the American Chemical Society
https://read.qxmd.com/read/30900879/synthesis-of-mo-3-s-4-clusters-from-half-sandwich-molybdenum-v-chlorides-and-their-application-as-platforms-for-mo-3-s-4-fe-cubes
#11
Yasuhiro Ohki, Ryota Hara, Kenichiro Munakata, Mizuki Tada, Tsutomu Takayama, Yoichi Sakai, Roger E Cramer
Triangular [Mo3 S4 ] clusters are known to serve as platforms to accommodate a metal atom M, furnishing cubic [Mo3 S4 M] clusters. In this study, three [Mo3 S4 ] clusters supported by η5 -cyclopentadienyl (CpR ) ligands, [CpR 3 Mo3 S4 ]+ (CpR = C5 Me4 SiMe3 , C5 Me4 SiEt3 , and C5 Me4 H), were synthesized via half-sandwich molybdenum chlorides CpR MoCl4 . In the cyclic voltammogram of the [Mo3 S4 ] cluster having C5 Me4 H ligands, a weak feature appeared in addition to the [CpR 3 Mo3 S4 ]0/- redox process, indicating the interaction between [CpR 3 Mo3 S4 ]- and the [Nn Bu4 ] cation of the electrolyte, while such a feature was less significant for the C5 Me4 SiR3 variants...
March 22, 2019: Inorganic Chemistry
https://read.qxmd.com/read/30900443/optics-of-perovskite-solar-cell-front-contacts
#12
Mohammad Ismail Hossain, Aswin Hongsingthong, Wayesh Qarony, Porponth Sichanugrist, Makoto Konagai, Alberto Salleo, Dietmar Knipp, Yuen Hong Tsang
The front contact has a major impact on the electrical and optical properties of perovskite solar cells. The front contact is part of the junction of the solar cell, must provide lateral charge transport to the terminals, should allow for an efficient light incoupling, while having low optical losses. The complex requirements of perovskite solar front contact will be described, and the optics of the front contact will be investigated. It will be shown that the front contact has a distinct influence on the short circuit current and energy conversion efficiency...
March 22, 2019: ACS Applied Materials & Interfaces
https://read.qxmd.com/read/30899927/synthesis-characterization-and-reactivity-of-dinuclear-organo-rare-earth-metal-alkyl-complexes-supported-by-2-amidate-functionalized-indolyl-ligands-substituent-effects-on-coordination-and-reactivity
#13
Dongjing Hong, Xiancui Zhu, Shaowu Wang, Yun Wei, Shuangliu Zhou, Zeming Huang, Shan Zhu, Ruru Wang, Wenrun Yue, Xiaolong Mu
Two series of new dinuclear organo-rare-earth-metal alkyl complexes supported by 2-amidate-functionalized indolyl ligands with different haptic modes were synthesized and characterized. The treatment of [RE(CH2SiMe3)3(THF)2] with 1 equiv. of 2-(2,6-iPr2C6H3NHC[double bond, length as m-dash]O)C8H5NH (H2L1) and 2-(2-tBuC6H4NHC[double bond, length as m-dash]O)C8H5NH (H2L2) in toluene yielded the dinuclear organo-rare-earth-metal alkyl complexes {[η1:(μ2-η1:η1)-L1]RE(CH2SiMe3)(THF)2}2 [RE = Gd (1a), Dy (1b), Y (1c), Er (1d), and Yb (1e)] and {[η1:(μ2-η1:η1):η1-L2]RE(CH2SiMe3)(THF)2}2 [RE = Gd (2a), Dy (2b), Y (2c), Er (2d), and Yb (2e)] in good yields...
March 22, 2019: Dalton Transactions: An International Journal of Inorganic Chemistry
https://read.qxmd.com/read/30899248/nucleotide-second-messenger-based-signaling-in-extreme-acidophiles-of-the-acidithiobacillus-species-complex-partition-between-the-core-and-variable-gene-complements
#14
Ana Moya-Beltrán, Camila Rojas-Villalobos, Mauricio Díaz, Nicolás Guiliani, Raquel Quatrini, Matías Castro
Cyclic and linear nucleotides are key elements of the signal transduction networks linking perception of the environment to specific cellular behavior of prokaryotes. These molecular mechanisms are particularly important in bacteria exposed to different, and frequently simultaneous, types of extreme conditions. This is the case in acidithiobacilli, a group of extremophilic bacteria thriving in highly acidic biotopes, that must also cope with significant variations in temperature, osmotic potentials and concentrations of various transition metals and metalloids...
2019: Frontiers in Microbiology
https://read.qxmd.com/read/30898078/gold-sensing-with-rhodamine-immobilized-hydrogel-based-colorimetric-sensor
#15
Sastiya Kampaengsri, Banchob Wanno, Thawatchai Tuntulani, Buncha Pulpoka, Chatthai Kaewtong
A highly sensitive and selective optical membrane for determination of Au3+ was synthesized by immobilization of a rhodamine derivative on agarose hydrogel. The sensing dye was synthesized by solvatochromism of rhodamine B via rhodamine lactone-zwitterion equilibrium. UV-vis spectroscopy, scanning electron microscopy (SEM), thermal gravimetric analysis (TGA) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) were employed to confirm that the rhodamine-lactone (RhoL) was incorporated into the agarose hydrogel...
March 21, 2019: Environmental Technology
https://read.qxmd.com/read/30897327/discovery-and-elucidation-of-counteranion-dependence-in-photoredox-catalysis
#16
Elliot P Farney, Steven J Chapman, Wesley B Swords, Marco D Torelli, Robert J Hamers, Tehshik P Yoon
Over the past decade, there has been a renewed interest in the use of transition metal polypyridyl complexes as photoredox catalysts for a variety of innovative synthetic applications. Many derivatives of these complexes are known, and the effect of ligand modifications on their efficacy as photoredox catalysts has been the subject of extensive, systematic investigation. However, the influence of the photocatalyst counteranion has received little attention, despite the fact that these complexes are generally cationic in nature...
March 21, 2019: Journal of the American Chemical Society
https://read.qxmd.com/read/30897189/synthesis-of-organometallic-pentalenide-complexes
#17
Stuart M Boyt, Niko A Jenek, Ulrich Hintermair
While a number of reports have established the unique structures and electronic properties of mono- and dinuclear pentalenide complexes of s, p, d and f block elements, access to these intriguing compounds is restricted by synthetic challenges. Here we review various strategies for the synthesis, functionalisation and (trans)metalation of pentalenide complexes from a practical point of view, pointing out promising avenues for future research that may allow wider access to novel pentalenide complexes for application in many different areas...
March 21, 2019: Dalton Transactions: An International Journal of Inorganic Chemistry
https://read.qxmd.com/read/30896919/graphene-oxide-enabled-synthesis-of-metal-oxide-origamis-for-soft-robotics
#18
Haitao Yang, Bok Seng Yeow, Ting-Hsiang Chang, Kerui Li, Fanfan Fu, Hongliang Ren, Po-Yen Chen
Origami structures have been widely applied in various technologies especially in the fields of soft robotics. Metal oxides (MOs) have recently emerged as unconventional backbone materials for constructing complex origamis with distinct functionalities. However, the MO origami structures reported in the literature were rigid and not deformable, thus limiting their applications from soft robotics. Herein, we reported a graphene oxide (GO)-enabled templating synthesis to produce complex MO origami structures from their paper origami templates with high structural replication...
March 21, 2019: ACS Nano
https://read.qxmd.com/read/30896918/on-controllability-and-applicability-of-surface-molecular-self-assemblies
#19
Lingbo Xing, Zhantao Peng, Wentao Li, Kai Wu
Molecular self-assembly (MSA) refers to spontaneous arrangement of molecular building blocks into ordered structures governed by weak interactions. Due to its high versatility and reversibility, MSA has been widely employed as a robust bottom-up approach to fabricating low-dimensional functional nanostructures, which are used in various applications in nanoscience and technology. To date, tremendous effort has been devoted to constructing various MSAs at surfaces, ranging from self-assembled monolayers and two-dimensional (2D) nanoporous networks to complex 2D quasicrystals and Sierpiński triangle fractals...
March 21, 2019: Accounts of Chemical Research
https://read.qxmd.com/read/30896292/spontaneous-reduction-of-low-potential-silver-i-dithiosulfate-complex-in-bioelectrochemical-systems-for-recovery-of-silver-and-simultaneous-electricity-production
#20
N A D Ho, S Babel
Waste fixer solutions generated from photographic processing are silver-rich effluents, in which silver exists in the form of a dithiosulfate complex ([Ag(S2 O3 )2 ]3- ), a stable and water-soluble chemical compound. This study investigated the electrochemical reduction of [Ag(S2 O3 )2 ]3- at different initial concentrations for silver recovery, combined with electricity production in a two-chamber bio-electrochemical system using a cation exchange membrane as the separator. During the biological oxidation of acetate to produce electrons in the anode chamber, [Ag(S2 O3 )2 ]3- was reduced spontaneously by acting as an electron acceptor in the cathode chamber, despite its low standard redox potential ([Ag(S2 O3 )2 ]3- /Ag0 , E0 = 0...
March 21, 2019: Environmental Technology
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