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101.
Adrián Schwarzenberg Farid Ichou Richard B. Cole Xavier Machuron‐Mandard Christophe Junot Denis Lesage Jean‐Claude Tabet 《Journal of mass spectrometry : JMS》2013,48(5):576-586
Organophosphorus compounds have played important roles as pesticides, chemical warfare agents and extractors of radioactive material. Structural elucidation of phosphonates poses a particular challenge because their initial forms can be hydrolyzed, thus, degradation products may predominate in samples acquired in the field. The analysis of non‐volatile organophosphorus compounds and their degradation products is possible using electrospray tandem mass spectrometry ESI‐MS/MS. Here, we present a generic strategy that allows the unambiguous identification of substituents for two families of organophosphorus compounds: the phosphonates and phosphates. General fragmentation rules were deduced based on the study of decomposition pathways of 55 organophosphorus esters, including examples found in the literature. Multistage MS (MSn) experiments at high resolution in a hybrid mass spectrometer provide accurate mass measurements, whereas collision‐induced dissociation experiments in a triple quadrupole give access to small fragment ions. The creation of a specific nomenclature for each possible structure of organophosphorus compound, depending on the alkyl side chain linked to the oxygen, was achieved by applying these fragmentation rules. This led to the creation of an ‘identification tree’ based upon the unique consecutive decomposition pathways uncovered for each individual compound. Hence, seven structural motifs were created that orient an unequivocal identification using the ‘identification tree’. Despite the similar structures of the ensemble of phosphate and phosphonate esters, distinct identifications based upon characteristic neutral losses and diagnostic fragment ions were possible in all cases. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
102.
Vadim A. Dubskikh Anna A. Lysova Denis G. Samsonenko Alexander N. Lavrov Konstantin A. Kovalenko Danil N. Dybtsev Vladimir P. Fedin 《Molecules (Basel, Switzerland)》2021,26(5)
Three new 3D metal-organic porous frameworks based on Co(II) and 2,2′-bithiophen-5,5′-dicarboxylate (btdc2−) [Co3(btdc)3(bpy)2]·4DMF, 1; [Co3(btdc)3(pz)(dmf)2]·4DMF·1.5H2O, 2; [Co3(btdc)3(dmf)4]∙2DMF∙2H2O, 3 (bpy = 2,2′-bipyridyl, pz = pyrazine, dmf = N,N-dimethylformamide) were synthesized and structurally characterized. All compounds share the same trinuclear carboxylate building units {Co3(RCOO)6}, connected either by btdc2– ligands (1, 3) or by both btdc2– and pz bridging ligands (2). The permanent porosity of 1 was confirmed by N2, O2, CO, CO2, CH4 adsorption measurements at various temperatures (77 K, 273 K, 298 K), resulted in BET surface area 667 m2⋅g−1 and promising gas separation performance with selectivity factors up to 35.7 for CO2/N2, 45.4 for CO2/O2, 20.8 for CO2/CO, and 4.8 for CO2/CH4. The molar magnetic susceptibilities χp(T) were measured for 1 and 2 in the temperature range 1.77–330 K at magnetic fields up to 10 kOe. The room-temperature values of the effective magnetic moments for compounds 1 and 2 are μeff (300 K) ≈ 4.93 μB. The obtained results confirm the mainly paramagnetic nature of both compounds with some antiferromagnetic interactions at low-temperatures T < 20 K in 2 between the Co(II) cations separated by short pz linkers. Similar conclusions were also derived from the field-depending magnetization data of 1 and 2. 相似文献
103.
Bernard Lavielle Bertrand Thomas Eric Gilabert Gregory Canchel Denis Horlait Sylvain Topin Fabien Pointurier Christophe Moulin 《Journal of mass spectrometry : JMS》2016,51(10):908-913
A double focusing sector field mass filter used in Nier–Johnson geometry has been built in order to perform Kr isotope enrichment for 81Kr and 85Kr isotopes. The principle consists in implanting Kr+ ions accelerated at 7 keV in Al foils after separation using the magnetic sector. A specific ion source has been designed capable of generating high Kr+ ion beams (>0.5 μA) to transfer into the collecting Al foils in 3 to 5 h significant fractions of large Kr samples (1015 to 1016 atoms) initially introduced in the instrument. Implanted Kr isotopes can be further selectively released from the Al foil by surface ablation using an infrared laser beam. Implantation yields and enrichment factors are measured using a conventional mass spectrometer. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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106.
A new approach to caerulomycins A and E via a 6-methyl-2-(2-pyridyl)-4H-pyran-4-one is described. The pyranone precursor is prepared by Claisen condensation of acetylacetone enol ether with ethyl picolinate. 相似文献
107.
Charge transport and contact resistance in coplanar devices based on colloidal polyaniline dispersion 下载免费PDF全文
Appan Merari Masillamani Nikola Peřinka Milena Hajná Jaroslav Stejskal Denis Tondelier Yvan Bonnassieux Jean‐Charles Vanel Bernard Geffroy Denis Mencaraglia 《Journal of Polymer Science.Polymer Physics》2016,54(17):1710-1716
The charge transport properties of thin films prepared from colloidal dispersion of polyaniline stabilized by poly(N‐vinylpyrrolidone) (PANI/PVP) have been investigated. The electrical characterization of coplanar device comprising of gold electrodes and PANI/PVP film deposited by spin coating served to gain insights into the contact and bulk resistance. The films prepared from PANI/PVP colloidal dispersion show high stability over a large temperature range. Temperature dependent measurements in the range from 90 to 350 K reveal that the charge transport can be described by a three‐dimensional variable‐range hopping mechanism as the dominant mode in the films. The stability of the films cast from dispersion within a large temperature range opens the possibility of the application as a polymer semiconductor layer in sensors and charge‐transport interlayer in organic solar cells. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 1710–1716 相似文献
108.
Dr. Julyan H. E. Cartwright Dr. Denis Gebauer Dr. C. Ignacio Sainz‐Díaz 《Angewandte Chemie (International ed. in English)》2012,51(48):11960-11970
Although the polymorphism of calcium carbonate is well known, and its polymorphs—calcite, aragonite, and vaterite—have been highly studied in the context of biomineralization, polyamorphism is a much more recently discovered phenomenon, and the existence of more than one amorphous phase of calcium carbonate in biominerals has only very recently been understood. Here we summarize what is known about polyamorphism in calcium carbonate as well as what is understood about the role of amorphous calcium carbonate in biominerals. We show that consideration of the amorphous forms of calcium carbonate within the physical notion of polyamorphism leads to new insights when it comes to the mechanisms by which polymorphic structures can evolve in the first place. This not only has implications for our understanding of biomineralization, but also of the means by which crystallization may be controlled in medical, pharmaceutical, and industrial contexts. 相似文献
109.
Sébastien Bau Denis Bémer Florence Grippari Jean-Christophe Appert-Collin Dominique Thomas 《Journal of nanoparticle research》2014,16(10):1-13
The cysteamine-modified hyaluronic acid (HA) polymer was employed to coat quantum dots (QDs) through a convenient one-step reverse micelle method, with the final QDs hydrodynamic size of around 22.6 nm. The HA coating renders the QDs with very good stability in PBS for more than 140 days and resistant to large pH range of 2–12. Besides, the HA-coated QDs also show excellent fluorescence stability in BSA-containing cell culture medium. In addition, the cell culture assay indicates no significant cytotoxicity for MD-MB-231 breast cancer cells, and its targeting ability to cancer receptor CD44 has been demonstrated on two breast cancer cell lines. The targeting mechanism was further proved by the HA competition experiment. This work has established a new approach to help solve the stability and toxicity problems of QDs, and moreover render the QDs cancer targeting property. The current results indicate that the HA polymer-coated QDs hold the potential application for both in vitro and in vivo cancer imaging researches. 相似文献
110.
Modulation of the Physicochemical Properties of Donor–Spiro–Acceptor Derivatives through Donor Unit Planarisation: Phenylacridine versus Indoloacridine—New Hosts for Green and Blue Phosphorescent Organic Light‐Emitting Diodes (PhOLEDs) 下载免费PDF全文
Dr. Sébastien Thiery Dr. Denis Tondelier Bernard Geffroy Dr. Olivier Jeannin Dr. Joëlle Rault‐Berthelot Dr. Cyril Poriel 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(29):10136-10149
This work reports a detailed structure–property relationship study of a series of efficient host materials based on the donor–spiro–acceptor (D‐spiro‐A) design for green and sky‐blue phosphorescent organic light‐emitting diodes (PhOLEDs). The electronic and physical effects of the indoloacridine (IA) fragment connected through a spiro bridge to different acceptor units, namely, fluorene, dioxothioxanthene or diazafluorene moiety, have been investigated in depth. The resulting host materials have been easily synthesised through short, efficient, low‐cost, and highly adaptable synthetic routes by using common intermediates. The dyes possess a very high triplet energy (ET) and tuneable HOMO/LUMO levels, depending on the strength of the donor/acceptor combination. The peculiar electrochemical and optical properties of the IA moiety have been investigated though a fine comparison with their phenylacridine counterparts to study the influence of planarisation. Finally, these molecules have been incorporated as hosts in green and sky‐blue PhOLEDs. For the derivative SIA‐TXO2 as a host, external quantum efficiencies as high as 23 and 14 % have been obtained for green and sky‐blue PhOLEDs, respectively. 相似文献