Search results for "Molecular switch"
showing 10 items of 23 documents
Molecular Switching, Logics, and Memories
2013
The concepts of molecular switch, molecular logics and memories are intimately related. In this work a review of these three topics is given. While the main examples concern the field of inorganic chemistry, in a few cases organic systems are presented to better illustrate the concepts. The basic notions of the logics gates usually used by the nowadays computers is presented and the modus operandi to transpose these concepts to the molecular level is discussed. Examples of switches driven by external stimuli such as light-induced, metal-ion, redox, photobistable, and complexation–decomplexation are described in this chapter. The extension of switches working in solution to solid devices are…
On the FCNS⇆FC(NS) reaction: A matrix isolation and theoretical study
2015
Abstract The FCNS ⇆ FC(NS) photoisomerization process is a simple model system for molecular switches. Here, we examined the switching processes by experimental and theoretical methods. Prior matrix-isolation IR spectroscopic studies were complemented by matrix-isolation UV spectroscopic measurements to assist the interpretation of the mechanism of the ring closure and opening processes and to verify the accuracy of the computations on the vertical excitation energies. Vertical excitation energies were computed by the EOMEE-CCSD, MCSCF, and MR-CISD methods. Conical intersections were also searched for and three conical intersections along the reaction path FCNS → FC(NS) were located, one co…
Metallic Nanoparticles Linked to Molecular Switches as Signal Processing Devices
2009
We explore theoretically the use of nanoscale switches whose conductance can be varied between two states by an external stimulus to implement signal processing devices. The building block is formed by a metallic nanoparticle linked to two electrodes by an organic ligand and a molecular switch. The system implementation exploits the sharp current resonance of the system that occurs when the frequencies of the applied potential and the induced variation on the switch conductance coincide.
Device variability and circuit redundancy in signal processing based on nanoswitches
2009
Signal processing based on molecular switches whose conductance can be tuned by an external stimulus between two (on and off) states has been proposed recently (Cervera et al 2008 J. Appl. Phys. 104 084317). The basic building block is a metal nanoparticle linked to two electrodes by an organic ligand and a nanoswitch. The net charge delivered by this nanostructure exhibits a sharp resonance when the alternating potential applied between the electrodes has the same frequency as the periodic variation between the on and off conductance states induced on the nanoswitch. This resonance can be used to process an external signal by selectively extracting the weight of the different harmonics. Ho…
Towards Organization of Molecular Machines at Interfaces. Langmuir Films and Langmuir-Blodgett Multilayers of an Acid-Base Switchable Rotaxane
2006
In this context we investigated, for the first time, the organi-zation of a non-amphiphilic tricationic switchable rotaxaneand its dumbbell-shaped component into Langmuir films andLangmuir–Blodgett (LB) multilayers by using a cospreadingstrategy. The Langmuir films have been characterized by sur-face pressure–area (
Conformational and Tautomeric Control by Supramolecular Approach in Ureido-N-iso-propyl,N’-4-(3-pyridin-2-one)pyrimidine
2019
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Signal processing and frequency-dependent associative memory based on nanoswitches
2008
A signal processing concept based on nanoscale switches whose conductance can be tuned by an external stimulus between two (ON and OFF) states is proposed and analyzed theoretically. The building block of the system is formed by a metal nanoparticle linked to two electrodes by an organic ligand and a molecular switch. When we apply an alternating potential to the system of the same frequency as the periodic variation between the ON and OFF states induced on the switch, the net charge delivered by the system exhibits a sharp resonance. This resonance can be used to process an external signal by selectively extracting the weight of the different harmonics. In addition, a frequency-dependent a…
Proton‐Gated Ring‐Closure of a Negative Photochromic Azulene‐Based Diarylethene
2020
Abstract Proton‐responsive photochromic molecules are attractive for their ability to react on non‐invasive rapid optical stimuli and the importance of protonation/deprotonation processes in various fields. Conventionally, their acidic/basic sites are on hetero‐atoms, which are orthogonal to the photo‐active π‐center. Here, we incorporate azulene, an acid‐sensitive pure hydrocarbon, into the skeleton of a diarylethene‐type photoswitch. The latter exhibits a novel proton‐gated negative photochromic ring‐closure and its optical response upon protonation in both open and closed forms is much more pronounced than those of diarylethene photoswitches with hetero‐atom based acidic/basic moieties. …
Chemical design of coordination polymers and functional materials: from pore control in MOFs through spin dynamics in nanomagnets to rotaxanes in mol…
2022
El trabajo de esta tesis se enmarca en el diseño químico de polímeros de coordinación y de materiales funcionales para poder ser utilizados en el campo de los materiales moleculares. El capítulo 1 ofrece una visión de los avances más significativos en la química de coordinación, así como una introducción general de los materiales moleculares más relevantes en la actualidad. El objetivo es proporcionar al lector el conocimiento necesario para establecer las bases sobre los campos a tratar. El resto de capítulos está organizado de acuerdo con un aumento de la dimensionalidad, empezando con moléculas discretas y terminando con polímeros de coordinación. El capítulo dos describe dos estructuras…
Photoactive Yellow Protein Chromophore Photoisomerizes around a Single Bond if the Double Bond Is Locked
2020
Photoactivation in the Photoactive Yellow Protein, a bacterial blue light photoreceptor, proceeds via photo-isomerization of the double C=C bond in the covalently attached chromophore. Quantum chemistry calculations, however, have suggested that in addition to double bond photo-isomerization, the isolated chromophore and many of its analogues, can isomerize around a single C-C bond as well. Whereas double bond photo-isomerization has been observed with x-ray crystallography, experimental evidence for single bond photo-isomerization is currently lacking. Therefore, we have synthesized a chromophore analogue, in which the formal double bond is covalently locked in a cyclopentenone ring and ca…