Search results for "Volt"
showing 10 items of 2187 documents
Circuit proposals for high-voltage latching current limiters
2019
This work discusses some ideas to adapt existing low voltage Latching Current Limiter (LCL) circuits to high voltage operation to provide a basis for future designs. Component selection, driver and ancillary power supply are key issues discussed which eventually provides a high-voltage LCL proposal. Experimental validation of two different prototypes (380Vdc and 1kVdc) is included as well as some digital techniques to enhance LCL capabilities.
Light-controlled reversible modulation of frontier molecular orbital energy levels in trifluoromethylated diarylethenes
2017
Among bistable photochromic molecules, diarylethenes (DAEs) possess the distinct feature that upon photoisomerization they undergo a large modulation of their π-electronic system, accompanied by a marked shift of the HOMO/LUMO energies and hence oxidation/reduction potentials. The electronic modulation can be utilized to remote-control charge- as well as energy-transfer processes and it can be transduced to functional entities adjacent to the DAE core, thereby regulating their properties. In order to exploit such photoswitchable systems it is important to precisely adjust the absolute position of their HOMO and LUMO levels and to maximize the extent of the photoinduced shifts of these energ…
Nanowire iron(III) coordination polymer based on 1,2,4-triazolo[1,5-a]pyrimidine and chloride ligands
2019
Abstract The neutral ligand 1,2,4-triazolo[1,5-a]pyrimidine (tp) has been employed to prepare a new coordination compound of Fe(III), [FeCl3(tp)2]n (1). Compound 1 was investigated by single crystal X-ray diffraction and found to be a coordination polymer forming a ladder structure based on metal–ligand interactions, while H-bonding and aromatic interactions contribute to the supramolecular self-assembly into a 3D nanostructured material. The polymeric assembly is retained also in solution, where a metallo-supramolecular polymer based on coordinative metal–ligand binding is present, as shown by dynamic light scattering (DLS) measurements. The redox properties of the Fe(III) coordination pol…
Copper-Assisted Hemiacetal Synthesis: A Cu II Chain Obtained by a One-Step in situ Reaction of Picolinaldehyde
2014
International audience; The 1D polymer complex [Cu2(L)2(SCN)2]n (1 ) has been synthesised in a one‐step in situ reaction of picolinaldehyde with sodium thiocyanate. The complex 1 was characterised by FTIR spectroscopy, UV/Vis spectrophotometry and elemental analysis. The crystal structure of complex 1 shows that chains of dimer complexes are formed with tetra‐ and pentacoordinate copper centres alternately linked by one thiocyanato and two alkoxido bridges. Variable‐temperature magnetic measurements showed a strong antiferromagnetic interaction between the copper centres within the dimer mediated by the two alkoxido bridges with a J value of –374 cm–1, which is in agreement with the DFT‐cal…
New insights on the electronic, magnetic, electric and molecular structure of a bis-(4-cyanopyridine) iron(III) complex with the meso-tetrakis(4-meth…
2019
International audience; We have successfully synthesized and characterized a new low-spin iron(III) bis(4-cyanopyridine) complex with a meso-porphyrin substituted in the para positions of the phenyls by the methoxy group, namely the bis(4-cyanopyridine)[(meso-tetrakis(4-metoxyphenylporphyrinato)]iron(III) trifluoromethanesulfonate chlorobenzene monosolvate complex with the formula [FeIII(TMPP)(4-CNpy)2]SO3CF3.C6H5Cl (I). This species was characterized through ultraviolet–visible, Fourier-transform infrared and Mössbauer spectroscopy as well as by SQUID magnetometry, cyclic voltammetry, and X-ray crystallography. These characterizations indicated that our synthetic heme model is a low-spin (…
Synthesis, spectroscopic, cyclic voltammetry properties and molecular structure of the thiocyanato-N meso-tetratolylporphyrinato zinc(II) ion complex
2017
International audience; This paper describes the synthesis of the (thiocyanato-N)(meso-tetratolylporphyrinato)zinc(II) chlorobenzene monosolvate complex with the formula [K(2,2,2-crypt)][Zn(TTP)(NCS)]·C6H5Cl (I) using the cryptand-222 to solubilize potassium thiocyanate in chlorobenzene solvent. Complex (I) has been characterized by elementary analysis, IR, UV–vis, 1H NMR and MS, and the structure of this new zinc(II) metalloporphyrin been examined crystallographically. A cyclic voltammetry investigation was also carried out on this species. The title compound crystallizes in the triclinic, space group P-1, with a = 11.5151(7) Å, b = 15.212(10) Å, c = 20.1093(12) Å, α = 80.428(4)°, β = 74.9…
Azolium and acetate ions in DMF: Formation of free N-heterocyclic carbene. A voltammetric analysis
2016
In order to reveal the possible formation of free N-heterocyclic carbene (NHC) in DMF-azolium and acetate solutions, the proton exchange equilibrium between azolium cations and CH3COO− was investigated (by cyclic voltammetry) by adding CH3COOH or tetrabutylammonium acetate to DMF solutions of imidazolium or thiazolium salts of different acidity.The voltammetric analysis confirms that the deprotonation of the azolium cation by CH3COO− (with the formation of free NHC) is significant in the case of the more acidic thiazolium cations, while it is not effective with the less acidic imidazolium ones.Accordingly, the NHC-catalyzed benzoin condensation was carried out in DMF solutions of azolium sa…
Model for Solid State Voltammetry of Zeolite-Associated Species
2004
The electrochemical reduction/oxidation of zeolite-associated species is described from the model of Lovric and Scholz for redox conductive microcrystals and the model of Andrieux and Saveant for redox polymers. It is assumed that the reaction starts at the three-phase boundary between electrode, zeolite particle, and electrolyte. From this point, the reaction zone grows while electrons and charge-balancing cations diffuse perpendicularly along the zeolite. As a result, at short times, a Cottrell-type behavior, controlled by the diffusion of electrolyte countercations in the zeolite can be expected. At larger times, a thin-layer response in which electron hopping between adjacent redox site…
Screening of Iberian Coinage in the 2(th)-1(th) BCE Period Using the Voltammetry of Immobilized Particles
2019
[EN] The voltammetry of immobilized particles (VIMP) was applied for grouping a series of 86 Iberian coins nominally minted in the cities of Iltirta, Castulo and Obulco in the 2(th)-1(th) BCE period for which there are no chronological data. Using characteristic signatures for the reduction of cuprite, tenorite and lead corrosion products in the patina of the coins, voltammetric grouping of coins was proposed. Voltammetric data were found to be consistent with textural and compositional properties of the surface and subsurface of selected coins using FIB-FESEM-EDX. The obtained data confirmed a clear separation between the productions of Iltirta on one side, and those of Castulo and Obulco …
INNOVATIVE PHOTOVOLTAIC-THERMAL HEAT PUMP SOLUTIONS FOR DOMESTIC HOT WATER PRODUCTION
2022
With the rapid growth of energy consumption in the building sector and the consequent necessity to develop energy efficiency strategies, the application of heat pump systems seems to be a competitive solution to improve energy efficiency. In particular, air-source heat pump (ASHP) systems assisted by solar energy have drawn great attention, owing to their great feasibility in buildings for space heating/cooling and hot ater production purposes. The complementation system between solar and air energy can solve the poor performance of the air source heat pump under low-temperature conditions and can also make up for the shortcoming of the solar collector as an unstable energy source. Both sol…