Organic Radicals As Spin Filters

2010 ◽  
Vol 132 (11) ◽  
pp. 3682-3684 ◽  
Author(s):  
Carmen Herrmann ◽  
Gemma C. Solomon ◽  
Mark A. Ratner
Keyword(s):  
Organic Radicals ◽  
Spin Filters

scholarly journals The Anomalous Effect of Quantum Interference in Organic Spin Filters

2020 ◽  
Author(s):  
Ashima Bajaj ◽  
Prabhleen Kaur ◽  
Aakanksha Sud ◽  
Marco Berritta ◽  
Md. Ehesan Ali
Keyword(s):  
Quantum Interference ◽  
Density Functional ◽  
Organic Radicals ◽  
Spin Coupling ◽  
Anomalous Effect ◽  
Spin Filters ◽  
Molecular Conductance ◽  
Spin Spin Coupling ◽  
Spin Filtering

The molecular topology in the single-molecular nano-junctions through which the de Broglie wave propagates plays a crucial role in controlling the molecular conductance. The enhancement and reduction of the conductance due to constructive and destructive Quantum Interference (QI) in para and meta connected molecules respectively has already been well established. Herein, we investigated the influence of QI on spin transport in the molecular junctions containing organic radicals as magnetic centres. The role of the localized spins on the QI as well as on spin filtering capability is investigated employing density functional theory in combination with non-equilibrium Green's function (NEGF-DFT) techniques. Various organic radicals including nitroxide (NO), phenoxy (PO) and methyl (CH2) radicals attached to the central benzene ring of pentacene with different terminal connections (para and meta) to gold electrodes are examined. Due to more obvious QI effects, para connected pentacene is found to be more conductive than meta one. Surprisingly, on incorporating a radical centre, along with spin filtering, a significant quenching of QI effects is observed which manifests itself in such a way that the conductance of meta coupled radicals is found to be more than para by two orders of magnitude. The decoherence induced by radical centre is analysed and discussed in terms of spin-spin coupling of radical's unpaired electron with the tunneling electrons.<br>

scholarly journals The Anomalous Effect of Quantum Interference in Organic Spin Filters

2020 ◽  
Author(s):  
Ashima Bajaj ◽  
Prabhleen Kaur ◽  
Aakanksha Sud ◽  
Marco Berritta ◽  
Md. Ehesan Ali
Keyword(s):  
Quantum Interference ◽  
Density Functional ◽  
Organic Radicals ◽  
Spin Coupling ◽  
Anomalous Effect ◽  
Spin Filters ◽  
Molecular Conductance ◽  
Spin Spin Coupling ◽  
Spin Filtering

The molecular topology in the single-molecular nano-junctions through which the de Broglie wave propagates plays a crucial role in controlling the molecular conductance. The enhancement and reduction of the conductance due to constructive and destructive Quantum Interference (QI) in para and meta connected molecules respectively has already been well established. Herein, we investigated the influence of QI on spin transport in the molecular junctions containing organic radicals as magnetic centres. The role of the localized spins on the QI as well as on spin filtering capability is investigated employing density functional theory in combination with non-equilibrium Green's function (NEGF-DFT) techniques. Various organic radicals including nitroxide (NO), phenoxy (PO) and methyl (CH2) radicals attached to the central benzene ring of pentacene with different terminal connections (para and meta) to gold electrodes are examined. Due to more obvious QI effects, para connected pentacene is found to be more conductive than meta one. Surprisingly, on incorporating a radical centre, along with spin filtering, a significant quenching of QI effects is observed which manifests itself in such a way that the conductance of meta coupled radicals is found to be more than para by two orders of magnitude. The decoherence induced by radical centre is analysed and discussed in terms of spin-spin coupling of radical's unpaired electron with the tunneling electrons.<br>

scholarly journals The Anomalous Effect of Quantum Interference in Organic Spin Filters

2020 ◽  
Author(s):  
Ashima Bajaj ◽  
Prabhleen Kaur ◽  
Aakanksha Sud ◽  
Marco Berritta ◽  
Md. Ehesan Ali
Keyword(s):  
Quantum Interference ◽  
Density Functional ◽  
Organic Radicals ◽  
Spin Coupling ◽  
Anomalous Effect ◽  
Spin Filters ◽  
Molecular Conductance ◽  
Spin Spin Coupling ◽  
Spin Filtering

The molecular topology in the single-molecular nano-junctions through which the de Broglie wave propagates plays a crucial role in controlling the molecular conductance. The enhancement and reduction of the conductance due to constructive and destructive Quantum Interference (QI) in para and meta connected molecules respectively has already been well established. Herein, we investigated the influence of QI on spin transport in the molecular junctions containing organic radicals as magnetic centres. The role of the localized spins on the QI as well as on spin filtering capability is investigated employing density functional theory in combination with non-equilibrium Green's function (NEGF-DFT) techniques. Various organic radicals including nitroxide (NO), phenoxy (PO) and methyl (CH2) radicals attached to the central benzene ring of pentacene with different terminal connections (para and meta) to gold electrodes are examined. Due to more obvious QI effects, para connected pentacene is found to be more conductive than meta one. Surprisingly, on incorporating a radical centre, along with spin filtering, a significant quenching of QI effects is observed which manifests itself in such a way that the conductance of meta coupled radicals is found to be more than para by two orders of magnitude. The decoherence induced by radical centre is analysed and discussed in terms of spin-spin coupling of radical's unpaired electron with the tunneling electrons.<br>

Bimetallic Radical Redox-Relay Catalysis for the Isomerization of Epoxides to Allylic Alcohols

2019 ◽  
Author(s):  
Ke-Yin Ye ◽  
Terry McCallum ◽  
Song Lin
Keyword(s):  
Ring Opening ◽  
High Reactivity ◽  
Hydrogen Atom Transfer ◽  
Organic Radicals ◽  
Epoxide Ring ◽  
Allylic Alcohols ◽  
Epoxide Ring Opening ◽  
Bond Forming ◽  
Co Catalysts ◽  
The Rich

Organic radicals are generally short-lived intermediates with exceptionally high reactivity. Strategically, achieving synthetically useful transformations mediated by organic radicals requires both efficient initiation and selective termination events. Here, we report a new catalytic strategy, namely bimetallic radical redox-relay, in the regio- and stereoselective rearrangement of epoxides to allylic alcohols. This approach exploits the rich redox chemistry of Ti and Co complexes and merges reductive epoxide ring opening (initiation) with hydrogen atom transfer (termination). Critically, upon effecting key bond-forming and -breaking events, Ti and Co catalysts undergo proton-transfer/electron-transfer with one another to achieve turnover, thus constituting a truly synergistic dual catalytic system.<br>

scholarly journals Understanding the luminescent nature of organic radicals for efficient doublet emitters and pure-red light-emitting diodes

2020 ◽  
Vol 19 (11) ◽  
pp. 1224-1229 ◽  
Author(s):  
Alim Abdurahman ◽  
Timothy J. H. Hele ◽  
Qinying Gu ◽  
Jiangbin Zhang ◽  
Qiming Peng ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Red Light ◽  
Organic Radicals ◽  
Light Emitting

scholarly journals Flower-Shaped C-Dots/Co3O4{111} Constructed with Dual-Reaction Centers for Enhancement of Fenton-Like Reaction Activity and Peroxymonosulfate Conversion to Sulfate Radical

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 135
Author(s):  
Zhibin Wen ◽  
Qianqian Zhu ◽  
Jiali Zhou ◽  
Shudi Zhao ◽  
Jinnan Wang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Active Site ◽  
High Surface ◽  
High Surface Area ◽  
Reaction Centers ◽  
Organic Radicals ◽  
The Other ◽  
High Catalytic Activity ◽  
High Adsorption ◽  
High Turnover

Novel flower-shaped C-dots/Co3O4{111} with dual-reaction centers were constructed to improve the Fenton-like reaction activity and peroxymonosulfate (PMS) conversion to sulfate radicals. Due to the exposure of a high surface area and Co3O4{111} facets, flower-shaped C-dots/Co3O4{111} could provide more Co(II) for PMS activation than traditional spherical Co3O4{110}. Meanwhile, PMS was preferred for adsorption on Co3O4{111} facets because of a high adsorption energy and thereby facilitated the electron transfer from Co(II) to PMS. More importantly, the Co–O–C linkage between C-dots and Co3O4{111} induced the formation of the dual-reaction center, which promoted the production of reactive organic radicals (R•). PMS could be directly reduced to SO4−• by R• over C-dots. On the other hand, electron transferred from R• to Co via Co–O–C linkage could accelerate the redox of Co(II)/(III), avoiding the invalid decomposition of PMS. Thus, C-dots doped on Co3O4{111} improved the PMS conversion rate to SO4−• over the single active site, resulting in high turnover numbers (TONs). In addition, TPR analysis indicated that the optimal content of C-dots doped on Co3O4{111} is 2.5%. More than 99% of antibiotics and dyes were degraded over C-dots/Co3O4{111} within 10 min. Even after six cycles, C-dots/Co3O4{111} still remained a high catalytic activity.

scholarly journals Polyphosphorhydrazone-Based Radical Dendrimers

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1230
Author(s):  
Vega Lloveras ◽  
José Vidal-Gancedo
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Contrast Agents ◽  
Biomedical Applications ◽  
Organic Radicals ◽  
Resonance Imaging ◽  
Metal Free ◽  
Antioxidant Agents ◽  
New Type ◽  
Paramagnetic Properties

The search for new biomedical applications of dendrimers has promoted the synthesis of new radical-based molecules. Specifically, obtaining radical dendrimers has opened the door to their use in various fields such as magnetic resonance imaging, as anti-tumor or antioxidant agents, or the possibility of developing new types of devices based on the paramagnetic properties of organic radicals. Herein, we present a mini review of radical dendrimers based on polyphosphorhydrazone, a new type of macromolecule with which, thanks to their versatility, new metal-free contrast agents are being obtained, among other possible applications.

scholarly journals Efficient light-emitting diodes from organic radicals with doublet emission

2021 ◽  
Vol 129 (18) ◽  
pp. 180901
Author(s):  
John M. Hudson ◽  
Timothy J. H. Hele ◽  
Emrys W. Evans
Keyword(s):  
Light Emitting Diodes ◽  
Organic Radicals ◽  
Light Emitting

scholarly journals Interaction of Fullerenes with Organosilanes in the Ionization Chamber of a Mass Spectrometer under Electron Impact and the Reaction of C60with Tetraphenylsilane in Solution under UV Irradiation

2016 ◽  
Vol 2016 ◽  
pp. 1-9
Author(s):  
Yury I. Lyakhovetsky ◽  
Elena A. Shilova ◽  
Alexandra P. Pleshkova ◽  
Alexander I. Belokon ◽  
Sergey O. Yakushin ◽  
...  
Keyword(s):  
Electron Impact ◽  
Mass Spectrometer ◽  
Uv Irradiation ◽  
Ionization Chamber ◽  
Ion Source ◽  
Organic Radicals ◽  
Mechanistic Study ◽  
Mass Spectral ◽  
Additional Support ◽  
Derivatives Of

C60was shown to react with organosilanes Me4Si, Ph2SiH2, Ph2MeSiH, Ph4Si, andα-naphthylphenylmethylsilane in the electron ionization ion source of a mass spectrometer with the transfer of the corresponding organic radicals (Me, Ph, andα-naphthyl) from the silanes to the fullerene. The reactions were accompanied by hydrogen addition to some products and hydrogen loss from them. C70reacted with Me4Si analogously. A reaction mechanism involving homolytic dissociation of the silanes under electron impact to the corresponding organic radicals, which react further with C60at the surface of the ionization chamber of the mass spectrometer to give the respective adducts, was offered. A mechanistic study of the reaction of C60with Me4Si supported it. No silicon containing derivatives of the fullerenes were found. C60reacted with Ph4Si in solution under UV irradiation in a similar fashion furnishing phenyl derivatives of the fullerene. These results provide an additional support to the hypothesis formulated earlier thatthe homolytic reactive mass spectrometry of fullerenes (the reactions of fullerenes with other species in the ionization chambers of mass spectrometers and their mass spectral monitoring)can predict the reactivity of them toward the same reagents in solution to a significant extent.

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