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1.
Multiscale Approach to the Study of the Electronic Properties of Two Thiophene Curcuminoid Molecules
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Alvaro Etcheverry‐Berríos Ignacio Olavarría Dr. Mickael L. Perrin Raúl Díaz‐Torres Domingo Jullian Dr. Ingrid Ponce Dr. José H. Zagal Dr. Jorge Pavez Dr. Sergio O. Vásquez Dr. Herre S. J. van der Zant Dr. Diana Dulić Dr. Núria Aliaga‐Alcalde Dr. Monica Soler 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(36):12808-12818
We studied the electronic and conductance properties of two thiophene–curcuminoid molecules, 2‐thphCCM ( 1 ) and 3‐thphCCM ( 2 ), in which the only structural difference is the position of the sulfur atoms in the thiophene terminal groups. We used electrochemical techniques as well as UV/Vis absorption studies to obtain the values of the HOMO–LUMO band gap energies, showing that molecule 1 has lower values than 2 . Theoretical calculations show the same trend. Self‐assembled monolayers (SAMs) of these molecules were studied by using electrochemistry, showing that the interaction with gold reduces drastically the HOMO–LUMO gap in both molecules to almost the same value. Single‐molecule conductance measurements show that molecule 2 has two different conductance values, whereas molecule 1 exhibits only one. Based on theoretical calculations, we conclude that the lowest conductance value, similar in both molecules, corresponds to a van der Waals interaction between the thiophene ring and the electrodes. The one order of magnitude higher conductance value for molecule 2 corresponds to a coordinate (dative covalent) interaction between the sulfur atoms and the gold electrodes. 相似文献
2.
Mingolo N. Cesa Y. Martinez O.E. Etcheverry J.I. Rocca J.J. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》2000,28(2):386-393
The energy deposition efficiency and focal spot dynamics of electron beams produced by pulsed cold-cathode high-voltage glow discharges for metal surface treatment are investigated for two different cathode geometries. A concave cathode geometry in which the focusing is dominated by the convergence of the electric field lines in the cathode fall region is compared with flat cathode in which the focusing is exclusively caused by the self-generated magnetic field. Results of the treatment of AISI 4140 carbon steel samples show that the concave cathode geometry significantly increases the efficiency, reduces the threshold power necessary for melting, and is less sensitive to variations in the discharge parameters and sample position. The results of numerical modeling indicate that the observed increase in efficiency is caused by the longer persistence of the focal spot on the sample. The model can be used to predict the discharge parameters required for a desired treatment 相似文献
3.
The preparation of VO(PO2H2)2·H2O was possible by direct reduction of V2O5 with hypophosphorous acid or by interaction of VOSO4 and H3PO2 solutions, and subsequent crystallization. The compound was characterized by IR, electronic and ESR spectroscopy and X-ray powder diffractometry. Magnetic susceptibilities were measured in the temperature range between 100 and 300 K. The thermal decomposition was also investigated in detail, showing a very complex sequence of degradation steps which finally generate a polymeric V(III) phosphite. 相似文献
4.
E. G. Ferrer S. B. Etcheverry E. J. Baran 《Monatshefte für Chemie / Chemical Monthly》1993,124(4):355-366
Summary The synthesis of a new vanadyl(IV)/saccharin complex is reported. Its bonding characteristics differ considerably from all known divalent metal-saccharinates. In this complex a VO(OH)+ moiety is coordinated to a saccharin molecule through its carbonyl oxygen and to a saccharinate ion through its deprotonated nitrogen. Two water molecules complete the coordination sphere. X-ray powder diagrams, infrared- and electronic absorption-spectra were recorded and analyzed for the characterization of the compound and its coordination properties. Besides, the magnetic susceptibility and the thermal behaviour were also investigated. 相似文献
5.
D Pocaznoi B Erable L Etcheverry ML Delia A Bergel 《Physical chemistry chemical physics : PCCP》2012,14(38):13332-13343
The objective of the work was to give some first insight into an engineering-oriented approach to MFC design by focusing on anode optimisation. The effect of various parameters was firstly investigated in half cell set-ups under well-controlled conditions. Microbial anodes were formed from soil leachate under polarisation at -0.2 V vs. SCE with different concentrations of substrate, salt and buffer. It was shown that non-turnover CV could be used to assess the electroactive maturity of the anodes during polarisation. This first phase resulted in the definition of a set of optimal parameter values. In the second phase, an optimal anode was formed in a half-cell under the defined optimal conditions. A numerical approach was then developed to calculate the theoretical maximum power that the anode could provide in an ideal MFC. The concept of "ideal MFC" introduced here allowed the theoretical maximum power to be calculated on the sole basis of the kinetic characteristics of the anode. Finally, a MFC designed in the aim of approaching such ideal conditions generated stable power densities of 6.0 W m(-2), which were among the highest values reported so far. The discrepancy between the theoretical maximum (8.9 W m(-2)) and the experimental results pointed out some limit due to the source of inoculum and suggested possible paths to improvement. 相似文献
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Patricia A. M. Williams María S. Molinuevo Nora Okulik Alicia H. Jubert Susana B. Etcheverry 《应用有机金属化学》2005,19(6):711-718
Two new vanadyl(IV) complexes with the non‐steroidal antiinflammatory drugs Indomethacin and Diclofenac were synthesized and characterized by elemental analysis, electronic, diffuse reflectance and FTIR spectroscopies and thermal behavior. The structures of the oxo‐vanadium(IV) complexes were obtained by carrying out ab initio calculations (B3LY/3–21G**) owing to the difficulties of obtaining single crystals of good quality for X‐ray studies. Indomethacin and Diclofenac did not cause any effect when tested on cellular proliferation in two osteoblast‐cell lines in culture (MC3T3E1 and UMR106). The biological effect of the complexes depends on the cellular type and on the nature of the coordinated ligands. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
8.
Gianella Facchin Eduardo Kremer Daniel A. Barrio Susana B. Etcheverry Antonio J. Costa-Filho María H. Torre 《Polyhedron》2009
In this work the study of Calf Thymus DNA interaction with several Cu(l-dipeptide) complexes was reported. The binding stoichiometry (Cu(mmol)/DNAmol base) was determined and in an attempt to clarify the binding mode, EPR and CD experiments were performed. All the studied complexes interacted with DNA, in a more selective way than [Cu(H2O)6]2+, being the [Cu(ala-phe)] the complex with the highest interaction. The EPR experiments suggested that the monomeric species formed in solution were coordinated through a nitrogen atom of the DNA bases (inner-sphere binding) and the CD studies showed structural changes upon the DNA–complex interaction. Besides, the ratio Cu(mmol)/DNAmol base obtained by the binding stoichiometry experiments was close to that found by EPR and CD determinations. The effect on cell proliferation determined by the crystal violet bioassay on UMR106 rat osteosarcoma-derived cells showed that the [Cu(ala-phe)] complex exerted an antiproliferative action against this tumor line. 相似文献
9.
Carlos A. Franca Susana B. Etcheverry Reinaldo Pis Diez Patricia A. M. Williams 《Journal of Raman spectroscopy : JRS》2009,40(9):1296-1300
Arterial hypertension is a very common disease, which is treated with different medications such as Irbesartan. This compound is a nonpeptide antagonist of the receptor of the enzyme angiotensin II. The infrared and Raman spectra of this compound were recorded and discussed assisted with density functional theory using the 6‐31G** basis set and animated pictures. Irbesartan exists in two tautomeric forms which can be isolated in the solid state. The vibrational study has been recorded using a mixture of both forms. 13C, 15N and 1H NMR theoretical studies have been performed and compared with previously reported experimental data. Theoretical calculations allowed the determination of the main features of the A and B tautomers of Irbesartan both in the vibrational studies and in the NMR spectroscopy. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
10.
Diphosphate as a Bidentate Ligand. Spectroscopic Investigation of the Anion Bis(ethylenediamine)diphosphatocobaltate(III) The solid state infrared spectrum of Ba[Co(en)2P2O7]2 · 4 H2O and the visible spectrum of an aqueous solution of the complex were recorded. The vibrational and bond properties as well as the ligand characteristics of the bidentate P2O74? group are briefly discussed. 相似文献