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Lauren E VanGelder, Brittney E Petel, Olaf Nachtigall, Gabriel Martinez, William W Brennessel, Ellen M Matson
The success of nonaqueous redox flow battery technology requires synthetic advances in charge carrier design to increase compatibility with organic solvents. Herein, we build upon our previous discoveries related to the development of multimetallic charge carriers, with the report of high yielding syntheses of ether-functionalized polyoxovanadate-alkoxide clusters, [V6O7(OR)9(OCH2)3CR'], R = CH3, C2H5; R' = CH3, CH2OCH3, CH2OC2H4OCH3. Like their homoleptic congeners, [V6O7(OR)12] (R = CH3, C2H5), these clusters exhibit four redox events, spanning nearly a two-volt window, and demonstrate rapid electron transfer kinetics...
October 15, 2018: ChemSusChem
Xingzhou Peng, Marc Behl, Pengfei Zhang, Magdalena Mazurek-Budzyn Ska, Yakai Feng, Andreas Lendlein
Well-defined dihydroxy telechelic oligodepsipeptides (oDPs), which have a high application potential as building blocks for scaffold materials for tissue engineering applications or particulate carrier systems for drug delivery applications are synthesized by ring-opening polymerization (ROP) of morpholine-2,5-diones (MDs) catalyzed by 1,1,6,6-tetra-n-butyl-1,6-distanna-2,5,7,10-tetraoxacyclodecane (Sn(IV) alkoxide). In contrast to ROP catalyzed by Sn(Oct)2 , the usage of Sn(IV) alkoxide leads to oDPs, with less side products and well-defined end groups, which is crucial for potential pharmaceutical applications...
October 14, 2018: Macromolecular Bioscience
Britta Glowacki, Roman Pallach, Michael Lutter, Fabian Roesler, Hazem Alnasr, Cederic Thomas, Dieter Schollmeyer, Klaus Jurkschat
The syntheses of the novel amino alcohols MeN(CH2CH2CMe2OH)2 (1), MeN(CMe2CH2OH) (CH2CMe2OH) (2), MeN(CH2CH2CH2OH)(CH2CMe2OH) (3), MeN(CH2CH2CMe2OH)(CH2CMe2OH) (4), MeN (CH2CH2CMe2OH)(CH2CH2OH) (5) and MeN(CH2CH2OH) (CH2CH2CH2OH) (6) as well as of the spirocyclic tin (IV) alkoxides spiro-[n-BuN(CH2CMe2O)2]2Sn (7), spiro-[MeN (CH2CH2CMe2O)2]2Sn (8, spiro-[para-FC6H4N (CH2CMe2O)2]2Sn (9), spiro-[MeN(CMe2CH2O) (CH2CMe2O)]2Sn (10), spiro-[MeN (CH2CH2CH2O) (CH2CMe2O)]2Sn (11), spiro-[MeN(CH2CH2CMe2O) (CH2CMe2O)]2Sn (12), spiro-[MeN(CH2CH2CMe2O) (CH2CH2O)]2Sn (13) and spiro-[MeN(CH2CH2O) (CH2CH2CH2O)]2Sn (14) are reported...
October 13, 2018: Chemistry: a European Journal
F Li, R L Meyer, S H Carpenter, L E VanGelder, A W Nichols, C W Machan, M L Neidig, E M Matson
A series of NO-bound, iron-functionalized polyoxovanadate-alkoxide (FePOV-alkoxide) clusters have been synthesized, providing insight into the role of multimetallic constructs in the coordination and activation of a substrate. Upon exposure of the heterometallic cluster to NO, the vanadium-oxide metalloligand is oxidized by a single electron, shuttling the reducing equivalent to the {FeNO} subunit to form a {FeNO}7 species. Four NO-bound clusters with electronic distributions ranging from [VV3VIV2]{FeNO}7 to [VIV5]{FeNO}7 have been synthesized, and characterized via 1 H NMR, infrared, and electronic absorption spectroscopies...
August 14, 2018: Chemical Science
Antoine Douchez, Azade Geranurimi, William D Lubell
γ,δ-Unsaturated ketones, so-called homoallylic ketones, have served as versatile building blocks for the synthesis of a variety of heterocycles, carbocycles, natural products, and reactive intermediates. Procured by a variety of processes, including conjugate addition of vinyl organometallic reagents to unsaturated ketones, allylation of silyl enol ethers, and rearrangements, homoallylic ketones are often synthesized by step-intensive methods. The cascade addition of 2 equiv of vinyl Grignard reagent to a carboxylate was reported by the Lubell laboratory in 2003 to give effective access to homoallylic ketones from a variety of aromatic, aliphatic, and α-amino methyl esters...
October 5, 2018: Accounts of Chemical Research
Lin Fang, Belén Albela, Boting Yang, Yuting Zheng, Peng Wu, Mingyuan He, Laurent Bonneviot
The reaction between titanium alkoxides, [Ti(OR)4], and surface silanol groups is widely used to generate grafted oxo-hydroxo titanium species, the size of which is difficult to control. Partial capping of the surface silanols in the presence of the masking pattern of self-repulsing tetramethylammonium ions allows us to isolate surface silanol islets, on which isolated titanium ions and dimeric oxo titanium species can be generated up to 2 Ti/Si mol%. Above this loading, and up to ~ 8 Ti/Si mol%, higher oligomers (trimers, hexamers, octamers, and so on) are formed, reaching the size obtained at much lower loadings (<1 Ti/Si mol%) on a non-modified silica surface...
October 3, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Fabrizio Monda, Robert Madsen
Zinc oxide has been developed as a catalyst for the dehydrogenation of primary alcohols into carboxylic acids and hydrogen gas. The reaction is performed in mesitylene solution in the presence of potassium hydroxide followed by workup with hydrochloric acid. The transformation can be applied to both benzylic and aliphatic primary alcohols and the catalytically active species was shown to be a homogeneous compound by a hot filtration test. Dialkylzinc and strongly basic zinc salts also catalyze the dehydrogenation with similar results...
October 1, 2018: Chemistry: a European Journal
Mark Abubekerov, Vojtěch Vlček, Junnian Wei, Matthias E Miehlich, Stephanie M Quan, Karsten Meyer, Daniel Neuhauser, Paula L Diaconescu
Neutral zinc alkoxide complexes show high activity toward the ring-opening polymerization of cyclic esters and carbonates, to generate biodegradable plastics applicable in several areas. Herein, we use a ferrocene-chelating heteroscorpionate complex in redox-switchable polymerization reactions, and we show that it is a moderately active catalyst for the ring-opening polymerization of L-lactide, ɛ-caprolactone, trimethylene carbonate, and δ-valerolactone. Uniquely for this type of catalyst, the oxidized complex has a similar polymerization activity as the corresponding reduced compound, but displays significantly different rates of reaction in the case of trimethylene carbonate and δ-valerolactone...
September 28, 2018: iScience
Johannes Teichert, Thomas Doert, Michael Ruck
The mechanisms of the polyol reduction of copper(ii) compounds were investigated by various systematic experiments. The course of the reduction in ethylene glycol strongly depends on the anion present in solution. Elemental copper can only be obtained in high yields starting from Cu(NO3)2, Cu(OAc)2, or Cu(OH)2; but not from CuCl2 or CuSO4. Intermediate compounds were observed, namely Cu2O, and the alkoxide compounds Cu(C2H4O2) and Cu3(OAc)2(C2H4O2)2. Cu3(OAc)2(C2H4O2)2 was characterised by single-crystal X-ray diffraction...
October 9, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Cecilia Agustín-Sáenz, Maider Machado, Agnieszka Tercjak
Porous silica layers with outstanding antireflective properties have been prepared by acid-catalyzed sol-gel process in presence of organic phases as structure directing agents (SDA) and excess water, with the aim of offering a cost-competitive, easy up-scaling and high efficiency process that contributes to reduce current levelized cost of energy (LCOE) of concentrating photovoltaics (CPV). The process has been optimized by controlling the water/alkoxide ratio, which is an important structure-regulating tool, having a strong influence in the structural properties of sol-gel synthesized materials...
September 14, 2018: Journal of Colloid and Interface Science
Francesca Becherini, Caterina Durante, Elsa Bourguignon, Mario Li Vigni, Vincent Detalle, Adriana Bernardi, Patrizia Tomasin
BACKGROUND AND METHODS: Wall paintings and architectural surfaces in outdoor environments are exposed to several physical, chemical and biological agents, hence they are often treated with different products to prevent or slow down their deterioration. Among the factors that have to be taken into account in the selection of the most suitable treatment for decorated surfaces, the aesthetic compatibility with the substrate is of great importance in the cultural heritage field; minimizing colour variation after treatment application is a crucial issue in particular for painted surfaces...
September 21, 2018: Chemistry Central Journal
Josiah J Newton, Robert Britton, Chadron M Friesen
Here we report a convenient synthesis of thionoesters by base-catalyzed transesterification. Benzyl and alkyl thionobenzoates and thionoheterobenzoates were efficiently prepared using various alcohols catalyzed by the corresponding sodium alkoxide. This methodology features a broad substrate scope, good to excellent yields, short reaction times, while simultaneously driving the reaction toward completion through the removal of the methanol byproduct. We also report the conversion of a small collection of thionobenzoates into the corresponding α,α-difluorobenzyl ethers to demonstrate the conversion of alcohols into difluorobenzyl or difluoroheterobenzyl ethers, a process that could prove useful for lead optimization in medicinal chemistry...
October 4, 2018: Journal of Organic Chemistry
Surja B Ghale, Jerry G Lanorio, Alex A Nickel, Kent M Ervin
The competitive threshold collision-induced dissociation technique is used to examine conformational effects on the relative gas-phase acidities of selected alcohols. By use of HF and H2 O as reference acids in a local thermochemical network to obtain absolute acidities, the measured 0 K gas-phase acidities for the propanol and pentanol isomers are Δacid H0 (CH3 CH2 CH2 O-H) = 1563.9 ± 2.9 kJ/mol, Δacid H0 ((CH3 )2 CHO-H) = 1568.2 ± 2.7 kJ/mol, Δacid H0 (CH3 (CH2 )4 O-H) = 1556.4 ± 2.9 kJ/mol, and Δacid H0 ((CH3 )2 CHCH2 CH2 O-H) = 1556...
October 4, 2018: Journal of Physical Chemistry. A
Zhe-Chen Wang, Ya-Ke Li, Sheng-Gui He, Veronica M Bierbaum
The strategy of synthesizing diazeniumdiolates (X-N(O)=NO- ) through the coexistence of nitric oxide and alkoxides (RO- ) was introduced by Wilhelm Traube 120 years ago. Today, despite the wide use of diazeniumdiolate derivatives to release nitric oxide in the treatment of cancer, the first step of the reaction mechanism for diazeniumdiolate synthesis remains a mystery and is thought to be complex. We have studied the gas-phase reactions of nitric oxide with alkoxides at room temperature. An electron-coupled hydrogen transfer is observed, and the radical anion HNO- is the only ionic product in these reactions...
September 6, 2018: European Journal of Mass Spectrometry
Fujia Wang, Kostiantyn Turcheniuk, Baolin Wang, Ah-Young Song, Xiaolei Ren, Ashok Vallamattam, Angela Park, Kolby Hanley, Ting Zhu, Gleb Yushin
Fabrication and applications of lightweight, high load-bearing, thermally stable composite materials would benefit greatly from leveraging the high mechanical strength of ceramic nanowires (NWs) over conventional particles or micrometer-scale fibers. However, conventional synthesis routes to produce NWs are rather expensive. Recently we discovered a novel method to directly convert certain bulk bimetallic alloys to metal-organic NWs at ambient temperature and pressure. This method was demonstrated by a facile transformation of polycrystalline aluminum-lithium (AlLi) alloy particles to aluminum alkoxide NWs, which can be further transformed to mechanically robust aluminum oxide (Al2 O3 ) NWs...
October 3, 2018: Journal of the American Chemical Society
Xiaoyu Wu, Guangni Ding, Liqun Yang, Wenkui Lu, Wanfang Li, Zhaoguo Zhang, Xiaomin Xie
An alkoxide-catalyzed hydrosilylation of cyclic imides to isoquinolines was realized via tandem reduction and rearrangement. Using TMSOK as the catalyst and (EtO)2 MeSiH as the reductant, a series of cyclic imides containing different functional groups were reduced to the corresponding 3-aryl isoquinolines in moderate to good yields. The scenario of the reaction pathway was supposed to involve the reduction of imides to ω-hydroxylactams, which underwent rearrangement in the presence of a base catalyst, and then the carbonyl reduction, followed by siloxy elimination...
September 21, 2018: Organic Letters
Danilo Stinghen, Matteo Atzori, Caprici M Fernandes, Ronny R Ribeiro, Eduardo L de Sá, Davi F Back, Siddhartha O K Giese, David L Hughes, Giovana G Nunes, Elena Morra, Mario Chiesa, Roberta Sessoli, Jaísa F Soares
The distorted tetrahedral [V(OAd)4 ] alkoxide (OAd = 1-adamantoxide, complex 1) is the first homoleptic, mononuclear vanadium(IV) alkoxide to be characterized in the solid state by X-ray diffraction analysis. The compound crystallizes in the cubic P4̅3 n space group with two highly disordered, crystallographically independent molecules in the asymmetric unit. Spin Hamiltonian parameters extracted from low temperature X- and Q-band electron paramagnetic resonance (EPR) experiments performed for polycrystalline samples of 1, both in the concentrated (bulk) form and diluted in the diamagnetic [Ti(OAd)4 ] analogue, reveal a fully axial system with g z < g x , g y and A z ≫ A x , A y ...
September 17, 2018: Inorganic Chemistry
Tetsuo Umegaki, Yoshifumi Yamamoto, Qiang Xu, Yoshiyuki Kojima
This work reports the influence of the water/titanium alkoxide ratio during the preparation of titania-nickel composite particles on their morphology and catalytic activity toward the hydrolysis of ammonia borane. The titania-nickel composite particle catalysts were fabricated by using a sol-gel method, followed by an activation process in aqueous solution containing sodium borohydride and ammonia borane. From the scanning electron microscopy images and pore-size distributions calculated from nitrogen sorption data, the particle dispersion was significantly enhanced at ratios above 6000, and increased with increasing water/titanium alkoxide ratio...
August 2018: ChemistryOpen
Timothy J Boyle, Joshua Farrell, Daniel T Yonemoto, Jeremiah M Sears, Jessica M Rimsza, Diana Perales, Nelson S Bell, Roger E Cramer, LaRico J Treadwell, Peter Renehan, Casey J Adams, Michael T Bender, William Crowley
The impact on the morphology nanoceramic materials generated from group 4 metal alkoxides ([M(OR)4 ]) and the same precursors modified by 6,6'-(((2-hydroxyethyl)azanediyl)bis(methylene))bis(2,4-di- tert-butylphenol) (referred to as H3 -AM-DBP2 (1)) was explored. The products isolated from the 1:1 stoichiometric reaction of a series of [M(OR)4 ] where M = Ti, Zr, or Hf; OR = OCH(CH3 )2 (OPr i ); OC(CH3 )3 (OBu t ); OCH2 C(CH3 )3 (ONep) with H3 -AM-DBP2 proved, by single crystal X-ray diffraction, to be [(ONep)Ti( k4 ( O,O',O'',N)-AM-DBP2 )] (2), [(OR)M(μ( O)- k3 ( O',O'',N)-AM-DBP2 )]2 [M = Zr: OR = OPr i , 3·tol; OBu t , 4·tol; ONep, 5·tol; M = Hf: OR = OBu t , 6·tol; ONep, 7·tol]...
September 4, 2018: Inorganic Chemistry
Álvaro García-Romero, Alex J Plajer, Lucía Álvarez-Miguel, Andrew D Bond, Dominic S Wright, Raúl García-Rodríguez
Postfunctionalization of the aluminate anion [EtAl(6-Me-2-py)3 ]- (1) (2-py=2-pyridyl) with alkoxide ligands can be achieved by the selective reactions of the lithium salt 1 Li with alcohols in the appropriate stoichiometry. This method can be used to introduce 3- and 4-py functionality in the form of 3- and 4-alkoxymethylpyridyl groups, while maintaining the integrity of the aluminate framework, thereby giving entry to new supramolecular chemistry. Chirality can be introduced either by using a chiral alcohol as a reactant or by the stepwise reaction of 1 Li with two different nonchiral alcohols...
August 9, 2018: Chemistry: a European Journal
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