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https://www.readbyqxmd.com/read/28742967/molybdenum-0-dihapto-coordination-of-benzene-and-trifluorotoluene-the-stabilizing-and-chemo-directing-influence-of-a-cf3-group
#1
Jeffery T Myers, Jacob A Smith, Steven J Dakermanji, Justin H Wilde, Katy B Wilson, Philip J Shivokevich, W Dean Harman
The preparation of the complex TpMo(NO)(DMAP)(η2-PhCF3) (5) and TpMo(NO)(DMAP)(η2-benzene) (3) are described. The CF3 group is found to stabilize the metal-arene bond strength in 5 by roughly 3 kcal/mol, compared to 3, allowing the large-scale synthesis and isolation of the trifluorotoluene analog (5, 37 g, 70%). When a benzene solution of 5 is allowed to stand, clean conversion to the benzene analog 3 occurs, and this complex may be precipitated from solution upon the addition of pentane, and isolated...
July 25, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28742965/sequential-tandem-addition-reactions-to-a-tungsten-trifluorotoluene-complex-a-versatile-method-for-the-preparation-of-highly-functionalized-trifluoromethylated-cyclohexenes
#2
Katy B Wilson, Jeffery T Myers, Hannah S Nedzbala, Logan A Combee, Michal Sabat, W Dean Harman
The effects of an electron-withdrawing group on the organic chemistry of an η2-bound benzene ring are explored using the complex TpW(NO)(PMe3)(η2-PhCF3). This trifluorotoluene complex was found to undergo a highly regio- and stereoselective 1,2-addition reaction involving protonation of an ortho carbon followed by addition of a carbon nucleophile. The resulting 1,3-diene complexes can undergo a second protonation and nucleophilic addition with a range of nucleophiles including hydrides, amines, cyanide, and protected enolates...
July 25, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28741947/a-domino-azidation-c-h-amination-approach-towards-trifluoromethylsubstituted-imidazoles
#3
Haichao Ma, Xiaoyan Zhang, Liangliang Chen, Wei Yu
N-Alkyl enamines can be transformed into 2,4,5-trisubsituted imidazoles by reacting with (diacetoxyiodo) benzene and TMSN3 under the catalysis of a copper salt such as Cu(OAc)2. Tetrabutyl ammonium iodide was also capable of promoting the reaction. The transformations from N-alkyl enamines into 2,4,5-trisubsituted imidazoles took place in a domino azidation/intramolecular C(sp3)H amination pattern. The present reaction provides a new efficient method for the preparation of 5-(trifluoromethyl) imidazoles.
July 25, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28741860/autoinducer-sensing-microarrays-by-reporter-bacteria-encapsulated-in-hybrid-supramolecular-polysaccharide-hydrogels
#4
Ping Li, Xiaoqiu Dou, Mareike Müller, Chuanliang Feng, Matthew Wook Chang, Martin Frettlöh, Holger Schönherr
A generally applicable strategy to obtain mechanically robust hydrogels for the incorporation and containment of functional reporter bacteria for the microarray and microparticle-based detection and signaling of N-acyl homoserine lactone autoinducers (3OC12 HSL) at relevant concentrations is reported. For reinforcing hydrogels of 1,4-bi(phenylalanine-diglycol)-benzene (PDB), a hybrid hydrogel is formed by the combination of PDB self-assembly with Ca(2+) mediated alginate crosslinking. The different assembly mechanisms are shown not to interfere with each other and despite the more than four-fold increased moduli of the hydrogels, diffusion of autoinducers into the gels remains efficient and Escherichia coli pLuxR-green fluorescent protein (GFP) reporter bacteria are proliferating...
July 25, 2017: Macromolecular Bioscience
https://www.readbyqxmd.com/read/28738694/laccase-a-green-catalyst-for-the-biosynthesis-of-poly-phenols
#5
Jing Su, Jiajia Fu, Qiang Wang, Carla Silva, Artur Cavaco-Paulo
Laccases (benzene diol: oxidoreductases, EC 1.10.3.2) are able to catalyze the oxidation of various compounds containing phenolic and aniline structures using dissolved oxygen in water. Laccase structural features and catalytic mechanisms focused on the polymerization of aromatic compounds are reported. A description about the most recent research on the biosynthesis of chemicals and polymers is made. Selected applications of this technology are considered as well as the advantages, shortcomings and future needs related with the use of laccases...
July 24, 2017: Critical Reviews in Biotechnology
https://www.readbyqxmd.com/read/28738510/degradation-kinetics-and-mechanism-of-sulfadiazine-and-sulfamethoxazole-in-an-agricultural-soil-system-with-manure-application
#6
Yu Zhang, Shuangqing Hu, Hongchang Zhang, Genxiang Shen, Zhejun Yuan, Wei Zhang
Recently, under the application of waste-water, manure and biosolids, antibiotics have been used massively in agriculture resulted in antibiotic resistance and potential environmental risks. In the present study, the removal of sulfadiazine (SDZ) and sulfamethoxazole (SMX) in an agricultural soil system was explored. All the experiments were conducted under different incubation conditions for 49days. The experimental results indicated that all the degradation processes could effectively follow a first-order kinetic model...
July 18, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28738505/rethinking-aqueous-phase-diffusion-related-isotope-fractionation-contrasting-theoretical-effects-with-observations-at-the-field-scale
#7
Shu Xu, Barbara Sherwood Lollar, Brent E Sleep
Aqueous phase diffusion-related isotope fractionation (DRIF) was investigated through modelling to determine under what subsurface conditions carbon isotope DRIF effects would be observable using typical sampling approaches. A dispersive enrichment factor was defined based on heavy and light isotopologue dispersion coefficients. For a given ratio of source concentration (C0) to method detection limit (MDL), the maximum DRIF in a system increased linearly with transverse dispersive enrichment factor. Using this linear relationship, the critical dispersion enrichment factor for which DRIF would not be observable was quantified...
July 18, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28738265/ground-state-charge-transfer-complex-formation-of-some-metalloporphyrins-with-aromatic-solvents-further-theoretical-and-experimental-investigations
#8
Biswajit Roy, Mihir Ghosh, Prajna Mukherjee, Somnath Chowdhury, Bikash C Gupta, Koushik Majhi, Subrata Sinha
In our earlier work (Chem. Phys. Letts. 592 (2014) 149-154), a new broad band was observed in the near infrared region (700-900nm) of the steady state absorption spectra of some metalloporphyrins (zinc tetraphenylporphyrin, zinc octaethylporphyrin and magnesium octaethylporphyrin) in aromatic solvents (chlorobenzene, 1,2-dichlorobenzene, benzonitrile, benzene and toluene) at high concentrations (~10(-4)molL(-1)). The band was ascribed to be due to ground state charge transfer complexation between solute and solvent molecules...
July 19, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28737180/direct-arylation-of-inactivated-benzene-with-aryl-acyl-peroxides-toward-biaryls
#9
Changduo Pan, Jiawei Zhu, Rongzhen Chen, Jin-Tao Yu
A direct arylation of inactivated benzene with acyl peroxides was developed, affording biaryls in good to excellent yields. This transformation underwent a radical pathway under metal-free, base-free and additive-free conditions with good functional group compatibility.
July 24, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28736823/distinct-alignment-of-benzene-derivatives-in-stretched-polystyrene-and-polybutylacrylate-gels-specific-polymer-solute-interactions
#10
Thomas Niklas, Christian Steinmetzger, Franziska Rüttger, Dietmar Stalke, Michael John
We have measured the alignment of a range of benzene derivatives in cross-linked polystyrene (PS) and poly(butyl acrylate) (PBA) using a small number of residual dipolar couplings (RDCs) and simple geometric considerations. For apolar solutes in PS and protic solutes in PBA, the preferred molecular orientation does not coincide with the longest molecular axis (steric aligment). This behaviour may be explained by specific π-π and hydrogen bonding interactions between solute and polymer, respectively, the latter being confirmed by molecular dynamics (MD) simulations...
July 23, 2017: Magnetic Resonance in Chemistry: MRC
https://www.readbyqxmd.com/read/28735536/five-electronic-state-beyond-born-oppenheimer-equations-and-their-applications-to-nitrate-and-benzene-radical-cation
#11
Soumya Mukherjee, Bijit Mukherjee, Satrajit Adhikari
We present explicit form of Adiabatic to Diabatic Transformation (ADT) equations and expressions of non-adiabatic coupling terms (NACTs) for a coupled five-state electronic manifold in terms of ADT angles between electronic wavefunctions. ADT matrices eliminate the numerical instability arising from singularity of NACTs and transform the adiabatic Schrödinger equation to its diabatic form. Two real molecular systems NO3 and C6H6(+) (Bz(+)) are selectively chosen for the demonstration of workability of those equations...
July 24, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28735314/gene-expression-during-btex-biodegradation-by-a-microbial-consortium-acclimatized-to-unleaded-gasoline-and-a-pseudomonas-putida-strain-hm346961-isolated-from-it
#12
Jesus A Morlett-Chavez, Jose A Ascacio-Martinez, William E Haskins, Karim Acuña-Askar, Hugo A Barrera-Saldaña
Pseudomonas putida strain (HM346961) was isolated from a consortium of bacteria acclimatized to unleaded gasoline-contaminated water. The consortium can efficiently remove benzene, toluene, ethylbenzene and xylene (BTEX) isomers, and a similar capability was observed with the P. putida strain. Proteome of this strain showed certain similarities with that of other strains exposed to the hydrocarbon compounds. Furthermore, the toluene di-oxygenase (tod) gene was up-regulated in P. putida strain when exposed to toluene, ethylbenzene, xylene, and BTEX...
July 6, 2017: Polish Journal of Microbiology
https://www.readbyqxmd.com/read/28734877/enzymatic-and-free-radical-formation-of-cis-and-trans-epoxyeicosatrienoic-acids-in-vitro-and-in-vivo
#13
Theresa Aliwarga, Brianne S Raccor, Rozenn N Lemaitre, Nona Sotoodehnia, Sina A Gharib, Libin Xu, Rheem A Totah
Epoxyeicosatrienoic acids (EETs) are metabolites of arachidonic acid (AA) oxidation that have important cardioprotective and signaling properties. AA is an ω -6 polyunsaturated fatty acid (PUFA) that is prone to autoxidation. Although hydroperoxides and isoprostanes are major autoxidation products of AA, EETs are also formed from the largely overlooked peroxyl radical addition mechanism. While autoxidation yields both cis- and trans-EETs, cytochrome P450 (CYP) epoxygenases have been shown to exclusively catalyze the formation of all regioisomer cis-EETs, on each of the double bonds...
July 19, 2017: Free Radical Biology & Medicine
https://www.readbyqxmd.com/read/28734245/azaphenothiazines-promising-phenothiazine-derivatives-an-insight-into-nomenclature-synthesis-structure-elucidation-and-biological-properties
#14
REVIEW
Krystian Pluta, Małgorzata Jeleń, Beata Morak-Młodawska, Michał Zimecki, Jolanta Artym, Maja Kocięba, Ewa Zaczyńska
For the last two decades, classical phenothiazines have attracted attention of researchers, as the hitherto investigations have revealed many significant biological activities within this class of compounds, other than originally discovered neuroleptic ones. Important, new pharmaceutical results on phenothiazines, as 10-substituted dibenzothiazines, were recently highlighted in several reviews. Azaphenothiazines are structurally modified phenothiazines by substitution of one or both benzene rings in the phenothiazine ring system with the azine rings, such as: pyridine, pyridazine, pyrimidine, pyrazine, 1,2,4-triazine, quinoline, quinoxaline, benzoxazine and benzothiazine...
July 8, 2017: European Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/28733890/down-regulation-of-mirna-451a-and-mirna-486-5p-involved-in-benzene-induced-inhibition-on-erythroid-cell-differentiation-in-vitro-and-in-vivo
#15
Boxuan Liang, Yuncong Chen, Weixin Yuan, Fei Qin, Qian Zhang, Na Deng, Xuexing Liu, Xiaoju Ma, Xue Zhang, Bo Zhang, Qifei Deng, Ming Huang, Huanwen Tang, Linhua Liu, Wen Chen, Yongmei Xiao
Exposure to high-dose benzene leads to the inhibition of erythroid differentiation. However, whether lower doses of benzene exposure resemble high-dose effects in erythroid differentiation, as well as the underlying mechanisms, remains largely unknown. To identify the microRNAs (miRNAs) specifically responsible for benzene exposure and their regulatory role in erythroid differentiation, we performed miRNA microarray in CD34(+) hematopoietic progenitor cells isolated from human umbilical cord blood after treatment with hydroquinone (HQ), a metabolite of benzene at concentrations of 0, 1...
July 21, 2017: Archives of Toxicology
https://www.readbyqxmd.com/read/28732988/sonochemical-synthesis-of-two-nanostructured-silver-i-coordination-polymers-based-on-semi-rigid-bis-benzimidazole-ligands
#16
Shao Yun Hao, Yue Hua Li, Zeng Chuan Hao, Guang Hua Cui
Nanoparticles of two silver(I) coordination polymers (CPs), [Ag2(L1)2(DCTP)]n (1) and [Ag2(L2)(DCTP)]n (2) (L1=1,3-bis(5,6-dimethylbenzimidazol-1-ylmethyl)benzene, L2=1,4-bis(benzimidazol-1-yl)-2-butene, H2DCTP=2,5-dichloroterephthalic acid), were synthesized by the sonochemical approach and hydrothermal method. Both CPs were characterized by elemental analysis, IR spectra, single-crystal X-ray diffraction, scanning electron microscopy (SEM), and thermogravimetric analyses (TGA). CP 1 exhibits a 2D 4-connected sql net with the point symbol {4(4)...
November 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28732966/effect-of-ultrasonic-waves-on-the-water-turbidity-during-the-oxidation-of-phenol-formation-of-hydro-peroxo-complexes
#17
Natalia Villota, Jose M Lomas, Luis M Camarero
Analysis of the kinetics of aqueous phenol oxidation by a sono-Fenton process reveals that the via involving ortho-substituted intermediates prevails: catechol (25.0%), hydroquinone (7.7%) and resorcinol (0.6%). During the oxidation, water rapidly acquires color that reaches its maximum intensity at the maximum concentration of p-benzoquinone. Turbidity formation occurs at a slower rate. Oxidant dosage determines the nature of the intermediates, being trihydroxylated benzenes (pyrogallol, hydroxyhydroquinone) and muconic acid the main precursors causing turbidity...
November 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28732322/effects-of-environmental-pollutants-on-signaling-pathways-in-rat-pituitary-gh3-adenoma-cells
#18
Nicoletta Fortunati, Federica Guaraldi, Valentina Zunino, Federica Penner, Valentina D'Angelo, Francesco Zenga, Francesca Pecori Giraldi, Maria Graziella Catalano, Emanuela Arvat
An increased rate of acromegaly was reported in industrialized areas, suggesting an involvement of environmental pollutants in the pathogenesis and behavior of GH-secreting pituitary adenomas. Based on these premises, the aim of the study was to evaluate the effects of some widely diffused pollutants (i.e. benzene, BZ; bis(2-ethylhexyl) phthalate, DEHP and polychlorinated biphenyls, PCB) on growth hormone secretion, the somatostatin and estrogenic pathways, viability and proliferation of rat GH-producing pituitary adenoma (GH3) cells...
July 18, 2017: Environmental Research
https://www.readbyqxmd.com/read/28732290/synergistic-effect-of-uv-pretreated-fe-zsm-5-catalysts-for-heterogeneous-catalytic-complete-oxidation-of-voc-a-technology-development-for-sustainable-use
#19
Abdul Aziz, Kwang Soo Kim
In this work, the performance of benzene, toluene, ethylbenzene, and xylene (BTEX) removal and degradation from gas, air streams on UV pretreated Fe-ZSM-5 in a batch reactor at room temperature were studied. The Fe-ZSM-5 zeolite catalyst was prepared by hydrothermal reaction method. The influence of UV pre-irradiation time on the removal of BTEX were assessed by varying the time, ranging from 15min to 60smin. Then, sustainability of the activation of the catalyst resulted by UV pretreatment was studied by the four-cycle experiment with one time UV irradiation and after each cycle irradiation followed by BTEX removal after every cycle respectively...
July 10, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28731742/semiclassical-divide-and-conquer-method-for-spectroscopic-calculations-of-high-dimensional-molecular-systems
#20
Michele Ceotto, Giovanni Di Liberto, Riccardo Conte
A new semiclassical "divide-and-conquer" method is presented with the aim of demonstrating that quantum dynamics simulations of high dimensional molecular systems are doable. The method is first tested by calculating the quantum vibrational power spectra of water, methane, and benzene-three molecules of increasing dimensionality for which benchmark quantum results are available-and then applied to C_{60}, a system characterized by 174 vibrational degrees of freedom. Results show that the approach can accurately account for quantum anharmonicities, purely quantum features like overtones, and the removal of degeneracy when the molecular symmetry is broken...
July 7, 2017: Physical Review Letters
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