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81.
D. Ramírez K. Álvarez G. Riveros M. Tejos M. G. Lobos 《Journal of Solid State Electrochemistry》2014,18(10):2869-2884
This study was focused in the electrodeposition of both compact and nanostructured extrinsic n-type doped ZnO films, which was achieved with aluminum, gallium, and indium. These elements were directly added into a Zn(II) rich electrolyte with molecular oxygen acting as an oxide precursor in aqueous perchlorate media. This way, the use of nitrate ions, whose by-products are accumulated in the aqueous electrolyte, and chloride ions, an electrically active element in ZnO, was therefore avoided. Speciation diagrams, conditional solubility diagrams and a potentiodynamic study were used to explain the way in which extrinsic n-type ZnO can be prepared by electrochemical deposition. Relatively compact films with a highly preferred orientation along the c-axis were suitable for impedance measurements, thus allowing the measurement of their doping levels. Al- and Ga-doped lamellar nanostructures were successfully prepared when the nature of the anion was changed from perchlorate to sulfate. Under specific conditions, the structure of these films changed from opened and isolated nanosheets to interconnected ones. Morphological, optical, and crystallographic properties of these films were also analyzed. Results and discussion presented here should provide a better understanding toward the study of alternative materials in fields such as photovoltaics and photocatalysis. 相似文献
82.
83.
Ángela Martínez‐Peragón Dr. Delia Miguel Rocío Jurado Dr. José Justicia Prof. José M. Álvarez‐Pez Dr. Juan M. Cuerva Dr. Luis Crovetto 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(2):447-455
9‐Alkyl xanthenones with different aliphatic pendant groups have been easily prepared by means of nucleophilic addition of the corresponding Grignard derivative to a tert‐butyldimethylsilyl ether (TBDMS)‐protected 3,6‐dihydroxy‐xanthenone. The photophysical behavior of the new dyes has been explored by using absorption, steady‐state‐, and time‐resolved fluorescence measurements. We determined the equilibrium constants, visible spectral characteristics, fluorescence quantum yield, and decay times. Remarkably, they retain similar fluorescent properties of fluorescein including the characteristic phosphate‐mediated excited‐state proton‐transfer (ESPT) reaction. 6‐Hydroxy‐9‐isopropyl‐3H‐xanthen‐3‐one ( 5 ) was investigated in living cells; it presented a good permeability and efficient accumulation inside the cytosol. For the first time, we reported that the requirement of an aryl group at C‐9 is no longer needed and new fluorescent sensors can be therefore easily developed. 相似文献
84.
Coordination Chemistry of Cyclopropenylidene‐Stabilized Phosphenium Cations: Synthesis and Reactivity of Pd and Pt Complexes
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Ágnes Kozma Tobias Deden Dr. Javier Carreras Christian Wille Dr. Jekaterina Petuškova Jörg Rust Dr. Manuel Alcarazo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(8):2208-2214
A straightforward synthesis of cyclopropenylidene‐stabilized phosphenium cations 1 a – g through the reaction of [(iPr2N)2C3+Cl]BF4 with secondary phosphines is described. Their donor ability was evaluated by analysis of the CO stretching frequency in Rh complexes [RhCl(CO)L2](BF4)2 and electrochemical methods. The cyclopropenium ring induces a phosphite‐type behavior that can be tuned by the other two substituents attached to the phosphorus atom. Despite of the positive charge that they bear, phosphenium cations 1 a – g still act as two‐electron donor ligands, forming adducts with PdII and PtII precursors. Conversely, in the presence of Pd0 species, an oxidative insertion of the Pd atom into the Ccarbene–phosphorus bond takes place, providing dimeric structures in which each Pd atom is bonded to a cyclopropenyl carbene while two dialkyl/diaryl phosphide ligands serve as bridges between the two Pd centers. The catalytic performance of the resulting library of PtII complexes was tested; all of the cationic phosphines accelerated the prototype 6‐endo‐dig cyclization of 2‐ethynyl‐1,1′‐biphenyl to afford pentahelicene. The best ligand 1 g was used in the synthesis of two natural products, chrysotoxene and epimedoicarisoside A. 相似文献
85.
The π‐Back‐Bonding Modulation and Its Impact in the Electronic Properties of CuII Antineoplastic Compounds: An Experimental and Theoretical Study
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Juan Carlos García‐Ramos Dr. Rodrigo Galindo‐Murillo Araceli Tovar‐Tovar Ana Luisa Alonso‐Saenz Virginia Gómez‐Vidales Dr. Marcos Flores‐Álamo Dr. Luis Ortiz‐Frade Dr. Fernando Cortes‐Guzmán Dr. Rafael Moreno‐Esparza Prof. Antonio Campero Prof. Lena Ruiz‐Azuara 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(42):13730-13741
86.
Experimental and Theoretical Studies on Arene‐Bridged Metal–Metal‐Bonded Dimolybdenum Complexes
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Dr. Mario Carrasco Natalia Curado Dr. Eleuterio Álvarez Dr. Celia Maya Dr. Riccardo Peloso Prof. Dr. Manuel L. Poveda Dr. Amor Rodríguez Prof. Dr. Eliseo Ruiz Prof. Dr. Santiago Álvarez Prof. Dr. Ernesto Carmona 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(20):6092-6102
The bis(hydride) dimolybdenum complex, [Mo2(H)2{HC(N‐2,6‐iPr2C6H3)2}2(thf)2], 2 , which possesses a quadruply bonded Mo2II core, undergoes light‐induced (365 nm) reductive elimination of H2 and arene coordination in benzene and toluene solutions, with formation of the MoI2 complexes [Mo2{HC(N‐2,6‐iPr2C6H3)2}2(arene)], 3?C6H6 and 3?C6H5Me , respectively. The analogous C6H5OMe, p‐C6H4Me2, C6H5F, and p‐C6H4F2 derivatives have also been prepared by thermal or photochemical methods, which nevertheless employ different Mo2 complex precursors. X‐ray crystallography and solution NMR studies demonstrate that the molecule of the arene bridges the molybdenum atoms of the MoI2 core, coordinating to each in an η2 fashion. In solution, the arene rotates fast on the NMR timescale around the Mo2‐arene axis. For the substituted aromatic hydrocarbons, the NMR data are consistent with the existence of a major rotamer in which the metal atoms are coordinated to the more electron‐rich C?C bonds. 相似文献
87.
Susana Araceli Carrizales Álvarez Anna Ilyina Karla Monzerratt Gregorio Jáuregui José Luis Martínez Hernández Brenda Berenice Vazquez Gutiérrez Elda Patricia Segura Ceniceros Alejandro Zugasti Cruz Hened Saade Caballero Raúl Guillermo López Campos 《Applied biochemistry and biotechnology》2014,174(5):1945-1958
Avian influenza viruses preferentially bind to sialic acid alpha-2,3-galactose (N-SA-α-2,3-Gal) receptors on epithelial cells. Herein, we describe a procedure we have developed for isolation of N-SA-α-2,3-Gal receptors from porcine trachea using magnetic nanoparticles (NPs) coated with chitosan (NP-Ch) and functionalized with Maackia amurensis lectin (NP-lectin). Magnetic nanoparticles were coated with chitosan in a one-step co-precipitation, and then M. amurensis lectin was immobilized covalently using glutaraldehyde. Lectin coated nanoparticles were incubated with sialic acid enriched fraction of tracheal homogenate, and N-SA-α-2,3-Gal receptor was extracted under magnetic field in two cycles. The presence of 66.4 kDa protein was determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The interaction of immobilized receptor (NP-Ch-R) with M. amurensis lectin (NP-Ch-R-L) was demonstrated by Fourier transform infrared spectrometry (FTIR) and thermogravimetric analysis (TGA). 相似文献
88.
Álvaro Dávila García Sylvain Bernès Fernando Sartillo-Piscil Rosa Luisa Meza-León 《Journal of heterocyclic chemistry》2020,57(12):4373-4379
The enantiopure synthesis of a truncated tetradenolide is presented. Starting from the versatile Chiron 7,3-lactone-xylofuranose derivative (7,3-LXF), the enantiomerically pure synthesis of the title compound is obtained in six steps with a 40% overall yield. 相似文献
89.
Dr. Luis Martín-Gomis Sairaman Seetharaman David Herrero Prof. Dr. Paul A. Karr Prof. Dr. Fernando Fernández-Lázaro Prof. Dr. Francis D'Souza Prof. Dr. Ángela Sastre-Santos 《Chemphyschem》2020,21(20):2254-2262
The effect of donor-acceptor distance in controlling the rate of electron transfer in axially linked silicon phthalocyanine-C60 dyads has been investigated. For this, two C60-SiPc-C60 dyads, 1 and 2 , varying in their donor-acceptor distance, have been newly synthesized and characterized. In the case of C60-SiPc-C60 1 where the SiPc and C60 are separated by a phenyl spacer, faster electron transfer was observed with kcs equal to 2.7×109 s−1 in benzonitrile. However, in the case of C60-SiPc-C60 2 , where SiPc and C60 are separated by a biphenyl spacer, a slower electron transfer rate constant, kcs=9.1×108 s−1, was recorded. The addition of an extra phenyl spacer in 2 increased the donor-acceptor distance by ∼4.3 Å, and consequently, slowed down the electron transfer rate constant by a factor of ∼3.7. The charge separated state lasted over 3 ns, monitoring time window of our femtosecond transient spectrometer. Complimentary nanosecond transient absorption studies revealed formation of 3SiPc* as the end product and suggested the final lifetime of the charge separated state to be in the 3–20 ns range. Energy level diagrams established to comprehend these mechanistic details indicated that the comparatively high-energy SiPc.+-C60.− charge separated states (1.57 eV) populated the low-lying 3SiPc* (1.26 eV) prior returning to the ground state. 相似文献