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https://www.readbyqxmd.com/read/29157816/effect-of-ipomoea-aquatica-ethanolic-extract-in-streptozotocin-stz-induced-diabetic-rats-via-1-h-nmr-based-metabolomics-approach
#1
Azliana Abu Bakar Sajak, Ahmed Mediani, Maulidiani, Nur Sumirah Mohd Dom, Chandradevan Machap, Muhajir Hamid, Amin Ismail, Alfi Khatib, Faridah Abas
BACKGROUND: Ipomoea aquatica (locally known as "kangkung") has previously been reported to have hypoglycemic activities on glucose level in diabetes patients. However, the effect of I. aquatica ethanolic extract on the metabolites in the body has remained unknown. PURPOSE: This study provides new insights on the changes of endogenous metabolites caused by I. aquatica ethanolic extract and improves the understanding on the therapeutic efficacy and mechanism of I...
December 1, 2017: Phytomedicine: International Journal of Phytotherapy and Phytopharmacology
https://www.readbyqxmd.com/read/29152363/a-new-lanthanum-iii-complex-containing-acetyl-acetone-and-1h-imidazole
#2
Atsuya Koizumi, Takuya Hasegawa, Atsushi Itadani, Kenji Toda, Taoyun Zhu, Mineo Sato
In the title complex, di-aqua-(1H-imidazole-κN(3))(nitrato-κ(2)O,O')bis-(4-oxo-pent-2-en-2-olato-κ(2)O,O')lanthanum(III), [La(C5H7O2)2(NO3)(C3H4N2)(H2O)2], the La atom is coordinated by eight O atoms of two acetyl-acetonate (acac) anions acting as bidentate ligands, two water mol-ecule as monodentate ligands, one nitrate anions as a bidentate ligand and one N atom of an imidazolate (ImH) molecule as a monodentate ligand. Thus, the coordination number of the La atom is nine in a monocapped square anti-prismatic polyhedron...
November 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
https://www.readbyqxmd.com/read/29147516/a-new-route-to-n-aromatic-heterocycles-from-the-hydrogenation-of-diesters-in-the-presence-of-anilines
#3
Yiping Shi, Paul C J Kamer, David J Cole-Hamilton, Michelle Harvie, Emma F Baxter, Kate J C Lim, Peter Pogorzelec
The hydrogenation of dicarboxylic acids and their esters in the presence of anilines provides a new synthesis of heterocycles. [Ru(acac)3] and 1,1,1-tris(diphenylphosphinomethyl)ethane (triphos) gave good to excellent yields of the cyclic amines at 220 °C. When aqueous ammonia was used with dimethyl 1,6-hexadienoic acid, ε-caprolactam was obtained in good yield. A side reaction involving alkylation of the amine by methanol was suppressed by using diesters derived from longer chain and branched alcohols. Hydrogenation of optically pure diesters (dimethyl (R)-2-methylbutanedioate and dimethyl (S)-2-methylbutanedioate) with aniline afforded racemic 3-methyl-1-phenylpyrrolidine in 78% yield...
October 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/29117587/potent-removal-of-cyanobacteria-with-controlled-release-of-toxic-secondary-metabolites-by-a-titanium-xerogel-coagulant
#4
Xiaomeng Wang, Xin Wang, Zhongbo Wei, Shujuan Zhang
Cyanobacteria blooming is a serious environmental issue throughout the world. Removal of cyanobacterial cells from surface water with controlled release of cyanobacterial organic matter (COM), especially toxic microcystins (MCs), would potentially reduce the processing burden in follow-up water treatment. Coagulation is a key technique in water treatment. Herein, the potential application of a novel titanium xerogel coagulant (TXC) was evaluated for the treatment of cyanobacteria-laden water in terms of cyanobacteria removal efficiency, variation of cell viability, the release and evolution of COM in the floc accumulation and storage process...
October 30, 2017: Water Research
https://www.readbyqxmd.com/read/29115722/hydrogen-atom-transfer-initiated-radical-cyclization-of-alkene-tethered-ketones
#5
Josep Bonjoch, Ben Bradshaw, Mar Saladrigas, Caroline Bosch, Gisela V Saborit
An unprecedented hydrogen atom transfer-based C-C coupling reaction between alkenes and ketones using Fe(acac)3 and PhSiH3 in EtOH is described. This mild protocol features high site-selectivity and allows for the construction of sterically congested structures containing tertiary alcohols and quaternary centers. The overall process introduces a novel strategic bond disconnection for ring-closing reactions.
November 8, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/29114677/half-sandwich-complexes-of-ir-iii-rh-iii-and-ru-ii-with-the-maxphos-ligand-metal-centred-chirality-and-cyclometallation
#6
Juan Téllez, Albert Gallen, Joaquina Ferrer, Fernando J Lahoz, Pilar García-Orduña, Antoni Riera, Xavier Verdaguer, Daniel Carmona, Arnald Grabulosa
The reaction of the acetylacetonates [(η(5)-C5Me5)M(acac)Cl] with (SP)-[HMaxPhos][BF4] afforded cationic complexes with the formula (SM,RP)-[(η(5)-C5Me5)MCl(MaxPhos)][BF4] (M = Rh (1), Ir (2)). The reaction of (SP)-MaxPhos with [RuCl(μ-Cl)(η(6)-p-MeC6H4(i)Pr)]2 and NH4X afforded (SRu,RP)-[(η(6)-p-MeC6H4(i)Pr)RuCl(MaxPhos)][X] (X = BF4 (3), PF6 (3')). The complexes have been completely characterized by analytical and spectroscopic means, including the determination of the crystal structures of 1, 2 and 3'...
November 21, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/29099522/behaviour-of-dft-based-approaches-to-the-spin-orbit-term-of-zero-field-splitting-tensors-a-case-study-of-metallocomplexes-m-iii-acac-3-m-v-cr-mn-fe-and-mo
#7
Kenji Sugisaki, Kazuo Toyota, Kazunobu Sato, Daisuke Shiomi, Takeji Takui
Spin-orbit contributions to the zero-field splitting (ZFS) tensor (D(SO) tensor) of M(III)(acac)3 complexes (M = V, Cr, Mn, Fe and Mo; acac = acetylacetonate anion) are evaluated by means of ab initio (a hybrid CASSCF/MRMP2) and DFT (Pederson-Khanna (PK) and natural orbital-based Pederson-Khanna (NOB-PK)) methods, focusing on the behaviour of DFT-based approaches to the D(SO) tensors against the valence d-electron configurations of the transition metal ions in octahedral coordination. Both the DFT-based approaches reproduce trends in the D tensors...
November 3, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29094746/non-innocence-and-mixed-valency-in-tri-and-tetranuclear-ruthenium-complexes-of-a-heteroquinone-bridging-ligand
#8
Mohd Asif Ansari, Abhishek Mandal, Katharina Beyer, Alexa Paretzki, Brigitte Schwederski, Wolfgang Kaim, Goutam Kumar Lahiri
The redox-active ligand 5,7,12,14-tetraazapentacene-6,13-quinone = L forms structurally characterised compounds with three (1) or four (2) [Ru(acac)2] complex fragments in which each of the metals is N,O-chelated. The new tris- and tetrakis-bidentate chelate compounds exhibit ruthenium centres bridged at about 4 Å by quinone O atoms which are then situated across the pentacene π system at about 6-8 Å distance. Several electron transfer processes were observed by voltammetry (CV, DPV) and the intermediates identified by EPR and UV-Vis-NIR spectroelectrochemistry...
November 14, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/29083184/iron-catalyzed-hydroboration-of-aldehydes-and-ketones
#9
Sem Raj Tamang, Michael Findlater
We report an operationally convenient room temperature hydroboration of aldehydes and ketones employing Fe(acac)3 as precatalyst. The hydroboration of aldehydes and ketones proceeded efficiently at room temperature to yield, after work up, 1° and 2° alcohols; chemoselective hydroboration of aldehydes over ketones is attained under these conditions. We propose a sigma bond metathesis mechanism in which an Fe-H intermediate is postulated to be a key reactive species.
October 30, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/29083165/ultrafast-intersystem-crossing-in-acetylacetone-via-femtosecond-x-ray-transient-absorption-at-the-carbon-k-edge
#10
Aditi Bhattacherjee, Chaitanya Das Pemmaraju, Kirsten Schnorr, Andrew R Attar, Stephen R Leone
Molecular triplet states constitute a crucial gateway in the photochemical reactions of organic molecules by serving as a reservoir for the excess electronic energy. Here, we report the remarkable sensitivity of soft X-ray transient absorption spectroscopy for following the intricate electronic structure changes accompanying the non-adiabatic transition of an excited molecule from the singlet to the triplet manifold. Core-level X-ray spectroscopy at the carbon-1s K-edge (284 eV) is applied to identify the role of the triplet state (T1, (3)ππ*) in the ultraviolet-induced photochemistry of pentane-2,4-dione (acetylacetone, AcAc)...
November 9, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29071441/kinetic-characterization-of-the-inhibition-of-protein-tyrosine-phosphatase-1b-by-vanadyl-vo-2-chelates
#11
Jason Hon, Michelle S Hwang, Meara A Charnetzki, Issra J Rashed, Patrick B Brady, Sarah Quillin, Marvin W Makinen
Protein tyrosine phosphatases (PTPases) are a prominent focus of drug design studies because of their roles in homeostasis and disorders of metabolism. These studies have met with little success because (1) virtually all inhibitors hitherto exhibit only competitive behavior and (2) a consensus sequence H/V-C-X5-R-S/T characterizes the active sites of PTPases, leading to low specificity of active site directed inhibitors. With protein tyrosine phosphatase-1B (PTP1B) identifed as the target enzyme of the vanadyl (VO(2+)) chelate bis(acetylacetonato)oxidovanadium(IV) [VO(acac)2] in 3T3-L1 adipocytes [Ou et al...
December 2017: Journal of Biological Inorganic Chemistry: JBIC
https://www.readbyqxmd.com/read/29052984/complex-structural-landscape-of-titanium-organophosphonates-isolation-of-structurally-related-ti4-ti5-and-ti6-species-and-mechanistic-insights
#12
Kamna Sharma, Rajendran Antony, Alok Ch Kalita, Sandeep Kumar Gupta, Paul Davis, Ramaswamy Murugavel
[Ti(acac)2(O(i)Pr)2] reacts with tert-butylphosphonic acid to yield a series of titanium organophosphonates such as tetranuclear [Ti4(acac)4(μ-O)2(μ-(t)BuPO3)2(μ-(t)BuPO3H)4]·2CH3CN (1), pentanuclear [Ti5(acac)5(μ-O)2(O(i)Pr)(μ-(t)BuPO3)4(μ-(t)BuPO3H)2] (2), hexanuclear [Ti6(acac)6(μ-O)2(O(i)Pr)2(μ-(t)BuPO3)6] (3), or [Ti6(acac)6(μ-O)3(O(i)Pr)(μ-(t)BuPO3)5(μ-(t)BuPO3H)]·2CH3CN (4). The isolation of each of these products in pure form depends on the molar ratio of the reactants or the solvent medium...
November 6, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/29048908/co-catalyzed-direct-addition-of-allylic-c-sp-3-h-bonds-to-ketones
#13
Tsuyoshi Mita, Satoshi Hanagata, Kenichi Michigami, Yoshihiro Sato
By using Co(acac)2/Xantphos with AlMe3, the C(sp(3))-H bonds of allylarene derivatives were cleaved for reaction with various ketones, affording the homoallylic alcohols in moderate to good yields. The branch/linear selectivity depended on the steric and electronic factors of the ketone electrophiles. The intermediate in this reaction is thought to be a low-valent allylcobalt(I) species, which exhibits high nucleophilicity toward ketones.
October 19, 2017: Organic Letters
https://www.readbyqxmd.com/read/29043334/efficient-orange-red-electroluminescence-of-iridium-complexes-with-1-2-6-bis-trifluoromethyl-pyridin-4-yl-isoquinoline-and-4-2-6-bis-trifluoromethyl-pyridin-4-yl-quinazoline-ligands
#14
Hua-Bo Han, Rong-Zhen Cui, Guang-Zhao Lu, Zheng-Guang Wu, You-Xuan Zheng, Liang Zhou, Hongjie Zhang
Two novel iridium(iii) complexes, Ir(tfmpiq)2(acac) (tfmpiq = 1-(2,6-bis(trifluoromethyl)pyridin-4-yl)isoquinoline, acac = acetylacetone) and Ir(tfmpqz)2(acac) (tfmpqz = 4-(2,6-bis(trifluoromethyl)pyridin-4-yl)quinazoline), were synthesized and thoroughly investigated. Both complexes emit orange-red photoluminescence with high quantum yields (Ir(tfmpiq)2(acac): λmax: 587 nm, ηPL: 42%; Ir(tfmpqz)2(acac): λmax: 588 nm, ηPL: 91%). Furthermore, the complex containing quinazoline shows higher electron mobility than that with isoquinoline...
November 7, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/29035811/moving-towards-fast-characterization-of-polymorphic-drugs-by-solid-state-nmr-spectroscopy
#15
Rosalynn Quiñones, Robbie J Iuliucci, Grayce Behnke, Ryanne Brown, Deben Shoup, Taylor M Riedel, Christine Plavchak, Brooke E Lininger, Jonathan M Spehar
Solid-state nuclear magnetic resonance (SS-NMR) spectroscopy has become a common technique to study polymorphism in pharmaceutical solids at high-resolution. However, high-throughput application of high resolution SS-NMR spectroscopy is severely limited by the long (1)H spin-lattice relaxation (T1) that is common to solid phase compounds. Here, we demonstrate the use of paramagnetic relaxation reagents such as chromium (III) acetylacetonate (Cr(acac)3) and nickel (II) acetylacetonate (Ni(acac)2) for fast data acquisition by significantly reducing the T1 value for carbamazepine Forms I, II, III, and dihydrate, cimetidine Forms A and B, nabumetone Form I, and acetaminophen Form I polymorphs...
October 3, 2017: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/28991299/amidine-functionalized-phosphines-tuneable-ligands-for-transition-metals
#16
Lewis C Wilkins, Rebecca L Melen, James A Platts, Paul D Newman
Attachment of racemic 1,3,5,7-tetramethyl-2,4,6-trioxa-8-phosphatricyclo[3.3.1.1(3,7)]decane (α,β-CgP) to (1R,5S)-1,8,8-trimethyl-2,4-diazabicyclo[3.2.1]oct-2-ene gave a diastereomeric mixture of a novel amidine-phosphine ligand, α,β-CgPAm. The phosphination was completely selective for the 4-position of the bicyclic amidine and there was no subsequent 1,2-migration of the α,β-CgP group. Methylation of the non-phosphinated nitrogen gave the amidinium salt [α,β-CgPAmMe]BF4 as a diastereomeric mixture...
October 24, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28980420/the-structure-of-mn-acac-3-a-rare-experimental-evidence-of-a-static-jahn-teller-effect-in-the-gas-phase
#17
Raphael Johann Friedrich Berger, Georgiy V Girichev, Nina I Giricheva, Angelika A Petrova, Natalya V Tverdova
The structure of free manganese(III) tris(acetylacetonate) [Mn(acac)3] was determined by mass-spectrometrically controlled gas-phase electron diffraction. The vapor of Mn(acac)3 at 125(5)°C is composed of a single conformer of Mn(acac)3 in C2 symmetry with the central structural motif of a tetragonal elongated MnO6 octahedron and 47(2) Mol% of acetylacetone (Hacac) formed by partial thermal decomposition of tris(acetylacetonate). Three types of Mn-O distances have been refined (rh1 = 2.157(16), 1.946(5) and 1...
October 5, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28972220/polypyridyl-functionalizated-alkynyl-gold-i-metallaligands-supported-by-tri-and-tetradentate-phosphanes
#18
Montserrat Ferrer, Leticia Giménez, Albert Gutiérrez, João Carlos Lima, Manuel Martínez, Laura Rodríguez, Avelino Martín, Rakesh Puttreddy, Kari Rissanen
A series of alkynyl gold(i) tri and tetratopic metallaligands of the type [Au3(C[triple bond, length as m-dash]C-R)3(μ3-triphosphane)] (R = 2,2'-bipyridin-5-yl or C10H7N2, 2,2':6',2''-terpyridin-4-yl or C15H10N3; triphosphane = 1,1,1-tris(diphenylphosphanyl)ethane or triphos, 1,3,5-tris(diphenylphosphanyl)benzene or triphosph) and [Au4(C[triple bond, length as m-dash]C-R)4(μ4-tetraphosphane)] (R = C10H7N2, C15H10N3; tetraphosphane = tetrakis(diphenylphosphanylmethyl)methane or tetraphos, 1,2,3,5-tetrakis(diphenylphosphanyl)benzene or tpbz, tetrakis(diphenylphosphaneylmethyl)-1,2-ethylenediamine or dppeda) were obtained in moderate to good yields...
October 17, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28956601/high-nuclearity-lanthanide-titanium-oxo-clusters-as-luminescent-molecular-thermometers-with-high-quantum-yields
#19
Dong-Fei Lu, Zi-Feng Hong, Jing Xie, Xiang-Jian Kong, La-Sheng Long, Lan-Sun Zheng
Three heterometallic lanthanide-titanium oxo clusters (LnTOCs) formulated as Eu2Ti4(μ3-O)4(tbba)12(acac)2 (Eu2Ti4, 1, Hacac = acetylacetone), Eu5Ti4(μ3-O)6(tbba)20(Htbba)(THF)2 (Eu5Ti4, 2), and Eu8Ti10(μ3-O)14(Ac)2(tbba)34(H2O)4(THF)2(Htbba)2 (Eu8Ti10, 3) were prepared through the reactions of 4-tert-butylbenzoate (Htbba), rare-earth salts, and Ti(O(i)Pr)4. The solution luminescence investigation discovered a size-dependent quantum yield phenomenon in solution. A solid-state luminescence study showed that these three LnTOCs display temperature-dependent photoluminescent properties...
September 28, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28949144/highly-efficient-solution-processed-deep-red-organic-light-emitting-diodes-based-on-an-exciplex-host-composed-of-a-hole-transporter-and-a-bipolar-host
#20
Manli Huang, Bei Jiang, Guohua Xie, Chuluo Yang
With the aim to achieve highly efficient deep-red emission, we introduced an exciplex forming cohost, 4,4',4″-tris(3-methylphenylphenylamino)triphenylamine (m-MTDATA): 2,5-bis(2-(9H-carbazol-9-yl)phenyl)-1,3,4-oxadiazole (o-CzOXD) (1:1). Due to the efficient triplet up-conversion processes upon the exciplex forming cohost, excellent performances of the devices were achieved with deep-red emission. Using the heteroleptic iridium complexes as the guest dopants, the solution-processed deep-red phosphorescent organic light-emitting diodes (PhOLEDs) with the iridium(III) bis(6-(4-(tert-butyl)phenyl)phenanthridine)acetylacetonate [(TP-BQ)2Ir(acac)]-based phosphorescent emitter exhibited an electroluminescent peak at 656 nm and a maximum external quantum efficiency (EQE) of 11...
September 28, 2017: Journal of Physical Chemistry Letters
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