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Lothar Dunsch - One of the best experts on this subject based on the ideXlab platform.
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Endohedral metal or a Fullerene Cage based oxidation? Redox duality of nitride clusterFullerenes CexM3−xN@C78–88 (x = 1, 2; M = Sc and Y) dictated by the enCaged metals and the carbon Cage size
Nanoscale, 2014Co-Authors: Yang Zhang, Alexey A. Popov, Lothar DunschAbstract:Redox behavior of endohedral metalloFullerenes, in particular their oxidation process, can be classified as a Fullerene-based or endohedral species-based process according to the mechanism of the electron transfer. Here we report on the phenomenon of the strain-driven electrochemical behavior achieved by encapsulating the cerium-containing clusters into a series of carbon Cages ranging from C78 to C88. The Ce-based mixed metal nitride clusterFullerenes CexM3−xN@C2n (x = 1, 2; M = Sc or Y; 2n = 78–88) were synthesized and characterized. The magnitude of the inherent strain caused by the limited inner space of the carbon Cage for the relatively large nitride clusters can be varied by choosing different scaffold metals (Sc, Lu, or Y) to tailor the size of the enCaged CexM3−xN cluster and by matching the nitride cluster with different Fullerene Cages in the size range from C78 to C88. The redox properties of CexM3−xN@C2n were investigated by cyclic and square wave voltammetry. The mechanism of the electrochemical oxidation of Ce-based mixed metal nitride clusterFullerenes, in particular whether the Fullerene-based oxidation or the CeIII → CeIV process is observed, is found to be dependent on the scaffold metal and the size of the Fullerene Cage. The endohedral oxidation of CeIII to CeIV was observed for a number of compounds as revealed by the negative shift of their oxidation potentials with respect to the values measured for the non-Ce analogues. Experimental studies are supported by DFT calculations. We conclude that the prerequisites for the Ce-based endohedral oxidation process are suitable inherent cluster-Cage strain and sufficiently high oxidation potential of the Fullerene Cage.
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A multi-state single-molecule switch actuated by rotation of an encapsulated cluster within a Fullerene Cage
Chemical Physics Letters, 2012Co-Authors: Tian Huang, Shangfeng Yang, Jin Zhao, Min Feng, Alexey A. Popov, Lothar Dunsch, Hrvoje PetekAbstract:We demonstrate a single-molecule switch based on tunneling electron-driven rotation of a triangular Sc3N cluster within an icosahedral C80 Fullerene Cage among three pairs of enantiomorphic configurations. Scanning tunneling microscopy imaging of switching within single molecules and electronic structure theory identify the conformational isomers and their isomerization pathways. Bias-dependent action spectra and modeling identify the antisymmetric stretch vibration of Sc3N cluster to be the gateway for energy transfer from the tunneling electrons to the cluster rotation. Hierarchical switching of conductivity through the internal cluster motion among multiple stationary states while maintaining a constant shape, is advantageous for the integration of endohedral Fullerene-based single-molecule memory and logic devices into parallel molecular computing architectures.
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A molecular switch based on current-driven rotation of an encapsulated cluster within a Fullerene Cage.
Nano letters, 2011Co-Authors: Tian Huang, Shangfeng Yang, Jin Zhao, Min Feng, Alexey A. Popov, Lothar Dunsch, Hrvoje PetekAbstract:By scanning tunneling microscopy imaging and electronic structure theory, we investigate a single-molecule switch based on tunneling electron-driven rotation of a triangular Sc3N cluster within an icosahedral C80 Fullerene Cage among three pairs of enantiomorphic configurations. Bias-dependent action spectra and modeling implicate the antisymmetric stretch vibration of Sc3N cluster as the gateway for energy transfer from the tunneling electrons into the cluster rotation. Hierarchical switching of conductivity among multiple stationary states while maintaining a constant molecular shape, offers an advantage for the integration of endohedral Fullerene-based single-molecule switches into multiple logic state molecular devices.
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an endohedral redox system in a Fullerene Cage the ce based mixed metal cluster Fullerene lu2cen c80
Physical Chemistry Chemical Physics, 2010Co-Authors: Lin Zhang, Shangfeng Yang, Alexey A. Popov, Sabrina Klod, Peter Rapta, Lothar DunschAbstract:Redox reactions of endohedral Fullerenes, and especially their oxidation, usually result in a change of the redox state of the carbon Cage. Here we demonstrate that an oxidation of the endohedral species is possible bypassing the Fullerene Cage in an unprecedented reversible cascade electron transfer under anodic conditions. The first Ce-based non-scandium mixed-metal nitride clusterFullerene (NCF) Lu2CeN@C80(Ih) was synthesized and isolated. The electronic and vibrational properties of Lu2CeN@C80 are characterized by UV-vis-NIR and FTIR spectroscopies and the Cage structure of Lu2CeN@C80 is determined by 13C NMR spectroscopy to be C80(Ih). At room temperature the NMR peak positions are shifted from the normal values of the diamagnetic M3N@C80 NCFs because of the unpaired f-electron localized on the Ce atom in the Ce3+ state. The variable-temperature NMR study enabled the estimation of the diamagnetic terms in the 13C chemical shifts, which were found to be close to those of diamagnetic M3N@C80 NCFs. The electrochemical properties of Lu2CeN@C80 were investigated by cyclic and square wave voltammetry, revealing two electrochemically irreversible but chemically reversible reduction steps and one reversible oxidation step. As the oxidation potential is significantly less positive than that in all other M3N@C80 NCFs, we conclude that an oxidation of the endohedral Ce occurs with the formation of Lu2CeIVN@C80+, the first endohedral metalloFullerene species with the tetra-valent cerium atom. This hypothesis is also supported by DFT calculations.
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An endohedral redox system in a Fullerene Cage: the Ce based mixed-metal cluster Fullerene Lu2CeN@C80
Physical chemistry chemical physics : PCCP, 2010Co-Authors: Lin Zhang, Shangfeng Yang, Alexey A. Popov, Sabrina Klod, Peter Rapta, Lothar DunschAbstract:Redox reactions of endohedral Fullerenes, and especially their oxidation, usually result in a change of the redox state of the carbon Cage. Here we demonstrate that an oxidation of the endohedral species is possible bypassing the Fullerene Cage in an unprecedented reversible cascade electron transfer under anodic conditions. The first Ce-based non-scandium mixed-metal nitride clusterFullerene (NCF) Lu2CeN@C80(Ih) was synthesized and isolated. The electronic and vibrational properties of Lu2CeN@C80 are characterized by UV-vis-NIR and FTIR spectroscopies and the Cage structure of Lu2CeN@C80 is determined by 13C NMR spectroscopy to be C80(Ih). At room temperature the NMR peak positions are shifted from the normal values of the diamagnetic M3N@C80 NCFs because of the unpaired f-electron localized on the Ce atom in the Ce3+ state. The variable-temperature NMR study enabled the estimation of the diamagnetic terms in the 13C chemical shifts, which were found to be close to those of diamagnetic M3N@C80 NCFs. The electrochemical properties of Lu2CeN@C80 were investigated by cyclic and square wave voltammetry, revealing two electrochemically irreversible but chemically reversible reduction steps and one reversible oxidation step. As the oxidation potential is significantly less positive than that in all other M3N@C80 NCFs, we conclude that an oxidation of the endohedral Ce occurs with the formation of Lu2CeIVN@C80+, the first endohedral metalloFullerene species with the tetra-valent cerium atom. This hypothesis is also supported by DFT calculations.
Shangfeng Yang - One of the best experts on this subject based on the ideXlab platform.
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Pyramidal TiTb 2 C cluster encapsulated within the popular Ih (7)-C 80 Fullerene Cage
Inorganica Chimica Acta, 2017Co-Authors: Fupin Liu, Alexey A. Popov, Fei Jin, Song Wang, Shangfeng YangAbstract:Abstract Interplay between the encapsulated cluster and Fullerene Cage is crucial for the stability of endohedral clusterFullerene. Herein we report the synthesis and isolation of a new entrant of carbido clusterFullerene, TiTb2C@Ih(7)-C80. The molecular structure of TiTb2C@Ih(7)-C80 was determined unambiguously by single crystal X-ray diffraction, featuring a pyramidal TiTb2C cluster encapsulated within the popular Ih(7)-C80 Cage. To our knowledge, TiTb2C represents the first pyramidal cluster found for carbido clusterFullerenes. On the basis of a comparative study with the reported TiM2C@Ih(7)-C80 (M = Sc, Lu) carbido clusterFullerenes and M3N@Ih(7)-C80 (M = Sc, Y and lanthanide) nitride clusterFullerenes, we tentatively determined the borderline of the sum of the three M-C(N) bond lengths of M3N/C for the encapsulated M3N/C cluster changing from planar to pyramidal geometry as 6.15–6.20 A. The electrochemical analyses on TiM2C@Ih(7)-C80 unraveled the self-adaptive structural transformations existing in the TiM2C@Ih(7)-C80 (M = Er, Y, Dy and Tb) based on their similar cluster-Cage strain evaluated through electrochemical measurements.
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Cage shrinkage of Fullerene via a C2 loss: from IPR C90(28)Cl24 to nonclassical, heptagon-containing C88Cl22/24.
Inorganic Chemistry, 2013Co-Authors: Ilya N. Ioffe, Shangfeng Yang, Erhard Kemnitz, Lev N. Sidorov, Olga N. Mazaleva, Tao Wei, Sergey I. TroyanovAbstract:A new case of chlorination-promoted Fullerene Cage shrinkage is reported. Chlorination of C90 (isolated pentagon rule isomer no. 28) with VCl4 afforded C88Cl22 with a nonclassic carbon Cage (NCC) containing 1 heptagon and 13 pentagons including 2 fused pairs flanking the heptagon. The pathway of C2 abstraction from the C90 Cage is suggested on the basis of density functional theory calculations.
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A multi-state single-molecule switch actuated by rotation of an encapsulated cluster within a Fullerene Cage
Chemical Physics Letters, 2012Co-Authors: Tian Huang, Shangfeng Yang, Jin Zhao, Min Feng, Alexey A. Popov, Lothar Dunsch, Hrvoje PetekAbstract:We demonstrate a single-molecule switch based on tunneling electron-driven rotation of a triangular Sc3N cluster within an icosahedral C80 Fullerene Cage among three pairs of enantiomorphic configurations. Scanning tunneling microscopy imaging of switching within single molecules and electronic structure theory identify the conformational isomers and their isomerization pathways. Bias-dependent action spectra and modeling identify the antisymmetric stretch vibration of Sc3N cluster to be the gateway for energy transfer from the tunneling electrons to the cluster rotation. Hierarchical switching of conductivity through the internal cluster motion among multiple stationary states while maintaining a constant shape, is advantageous for the integration of endohedral Fullerene-based single-molecule memory and logic devices into parallel molecular computing architectures.
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A molecular switch based on current-driven rotation of an encapsulated cluster within a Fullerene Cage.
Nano letters, 2011Co-Authors: Tian Huang, Shangfeng Yang, Jin Zhao, Min Feng, Alexey A. Popov, Lothar Dunsch, Hrvoje PetekAbstract:By scanning tunneling microscopy imaging and electronic structure theory, we investigate a single-molecule switch based on tunneling electron-driven rotation of a triangular Sc3N cluster within an icosahedral C80 Fullerene Cage among three pairs of enantiomorphic configurations. Bias-dependent action spectra and modeling implicate the antisymmetric stretch vibration of Sc3N cluster as the gateway for energy transfer from the tunneling electrons into the cluster rotation. Hierarchical switching of conductivity among multiple stationary states while maintaining a constant molecular shape, offers an advantage for the integration of endohedral Fullerene-based single-molecule switches into multiple logic state molecular devices.
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an endohedral redox system in a Fullerene Cage the ce based mixed metal cluster Fullerene lu2cen c80
Physical Chemistry Chemical Physics, 2010Co-Authors: Lin Zhang, Shangfeng Yang, Alexey A. Popov, Sabrina Klod, Peter Rapta, Lothar DunschAbstract:Redox reactions of endohedral Fullerenes, and especially their oxidation, usually result in a change of the redox state of the carbon Cage. Here we demonstrate that an oxidation of the endohedral species is possible bypassing the Fullerene Cage in an unprecedented reversible cascade electron transfer under anodic conditions. The first Ce-based non-scandium mixed-metal nitride clusterFullerene (NCF) Lu2CeN@C80(Ih) was synthesized and isolated. The electronic and vibrational properties of Lu2CeN@C80 are characterized by UV-vis-NIR and FTIR spectroscopies and the Cage structure of Lu2CeN@C80 is determined by 13C NMR spectroscopy to be C80(Ih). At room temperature the NMR peak positions are shifted from the normal values of the diamagnetic M3N@C80 NCFs because of the unpaired f-electron localized on the Ce atom in the Ce3+ state. The variable-temperature NMR study enabled the estimation of the diamagnetic terms in the 13C chemical shifts, which were found to be close to those of diamagnetic M3N@C80 NCFs. The electrochemical properties of Lu2CeN@C80 were investigated by cyclic and square wave voltammetry, revealing two electrochemically irreversible but chemically reversible reduction steps and one reversible oxidation step. As the oxidation potential is significantly less positive than that in all other M3N@C80 NCFs, we conclude that an oxidation of the endohedral Ce occurs with the formation of Lu2CeIVN@C80+, the first endohedral metalloFullerene species with the tetra-valent cerium atom. This hypothesis is also supported by DFT calculations.
Shigeru Nagase - One of the best experts on this subject based on the ideXlab platform.
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Is the isolated pentagon rule always satisfied for metallic carbide endohedral Fullerenes
Inorganic Chemistry, 2012Co-Authors: Tao Yang, Xiang Zhao, Shengtao Li, Shigeru NagaseAbstract:Quantum-chemical calculations reveal that metallic carbide endohedral Fullerene Y2C2@C84 possesses a novel Fullerene Cage, C1(51383)-C84, with one pair of pentagon adjacencies. One of the encapsulated yttrium atoms is located on the adjacent pentagons, while the other stays on a hexagonal ring in the Fullerene Cage. As one of numerous metallic carbide endohedral Fullerenes, Y2C2@C1(51383)-C84 is the first example that violates the well-known isolated pentagon rule (IPR). More interestingly, compared with the fact that Sc2C2@C84 has a conventional IPR-satisfying Cage, D2d(51591)-C84, Y2C2@C84 utilizes the novel Fullerene Cage C1(51383)-C84 with one pair of pentagon adjacencies.
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methane in an open Cage 60 Fullerene
Journal of the American Chemical Society, 2009Co-Authors: Keith E Whitener, Naomi Mizorogi, Shoichi Iwamatsu, Shizuaki Murata, James R Cross, Martin Saunders, Shigeru NagaseAbstract:An endohedral methane complex of a Fullerene derivative is first synthesized by insertion of a methane molecule through the opening of an open-Cage C60 derivative. The trapped methane is confirmed by NMR spectroscopy and mass spectrometry. Both methane carbon and protons show remarkable upfield shifts in NMR, characteristic of a chemical species in a Fullerene Cage. CH4 protons appear as one equivalent signal in the 1H NMR spectrum, suggesting that even methane can rotate in a C60 Cage.
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Spectroscopic and theoretical study of endohedral dimetalloFullerene having a non-IPR Fullerene Cage: Ce2@C72.
The journal of physical chemistry. A, 2008Co-Authors: Michio Yamada, Takatsugu Wakahara, Takahiro Tsuchiya, Yutaka Maeda, Takeshi Akasaka, Naomi Mizorogi, Shigeru NagaseAbstract:The endohedral dimetalloFullerene having a non-IPR Fullerene Cage, Ce2@C72, is spectroscopically and theoretically characterized. The 13C NMR measurements display large temperature-dependent signals caused by paramagnetic shifts, indicating that the Ce atoms are located near the two fused pentagons in the C72 Cage. Theoretical calculations are performed to clarify the metal position, which are in good agreement with the result obtained by the paramagnetic 13C NMR analysis. Electrochemical measurements reveal that Ce2@C72 has particularly lower oxidation and higher reduction potentials than other endohedral dimetalloFullerenes.
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spectroscopic and theoretical study of endohedral dimetalloFullerene having a non ipr Fullerene Cage ce2 c72
Journal of Physical Chemistry A, 2008Co-Authors: Michio Yamada, Takatsugu Wakahara, Takahiro Tsuchiya, Yutaka Maeda, Takeshi Akasaka, Naomi Mizorogi, Shigeru NagaseAbstract:The endohedral dimetalloFullerene having a non-IPR Fullerene Cage, Ce2@C72, is spectroscopically and theoretically characterized. The 13C NMR measurements display large temperature-dependent signals caused by paramagnetic shifts, indicating that the Ce atoms are located near the two fused pentagons in the C72 Cage. Theoretical calculations are performed to clarify the metal position, which are in good agreement with the result obtained by the paramagnetic 13C NMR analysis. Electrochemical measurements reveal that Ce2@C72 has particularly lower oxidation and higher reduction potentials than other endohedral dimetalloFullerenes.
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a bowl shaped Fullerene encapsulates a water into the Cage
Journal of the American Chemical Society, 2004Co-Authors: Shoichi Iwamatsu, Shigeru Nagase, Takashi Uozaki, Kaoru Kobayashi, Shizuaki MurataAbstract:The sequential carbon−carbon bond cleaving reactions of the diketone derivative of C60 with o-phenylenediamine give a novel bowl-shaped Fullerene bearing a 20-membered ring orifice. The product reversibly encapsulates a water molecule into the Fullerene Cage for the first time.
Alan L Balch - One of the best experts on this subject based on the ideXlab platform.
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beyond the butterfly sc2c2 c2v 9 c86 an endohedral Fullerene containing a planar twisted sc2c2 unit with remarkable crystalline order in an unprecedented carbon Cage
Journal of the American Chemical Society, 2015Co-Authors: Chiahsiang Chen, Marilyn M Olmstead, Luis Echegoyen, Kamran B Ghiassi, Maira R Ceron, Miguel A Guerreroayala, Alan L BalchAbstract:The synthesis, isolation, and characterization of a new endohedral Fullerene, Sc2C88, is reported. Characterization by single crystal X-ray diffraction revealed that it is the carbide Sc2C2@C2v(9)-C86 with a planar, twisted Sc2C2 unit inside a previously unseen C2v(9)-C86 Fullerene Cage.
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Large metal ions in a relatively small Fullerene Cage: The structure of Gd3N@C2(22010)-C78 departs from the isolated pentagon rule
Journal of the American Chemical Society, 2009Co-Authors: Christine M Beavers, Marilyn M Olmstead, Luis Echegoyen, Manuel N Chaur, Alan L BalchAbstract:An isomerically pure sample of Gd3N@C78 has been extracted from the carbon soot formed in the electric-arc generation of Fullerenes using hollow graphite rods packed with Gd2O3 and graphite powder under an atmosphere of helium and dinitrogen. Purification has been achieved by chromatographic methods and the product has been characterized by mass spectrometry, UV/vis absorption spectroscopy, and cyclic voltammetry. Although a number of endohedral Fullerenes have been found to utilize the D3h(5)-C78 Cage, comparison of the spectroscopic and electrochemical properties of the previously characterized Sc3N@D3h(5)-C78 with those of Gd3N@C78 reveals significant differences that indicate that these two endohedrals do not possess the same Cage structure. A single crystal X-ray diffraction study indicates that the Fullerene Cage does not follow the isolated pentagon rule (IPR) but has two equivalent sites where two pentagons abut. The endohedral has been identified as Gd3N@C2(22010)-C78. Two of the gadolinium atoms...
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large metal ions in a relatively small Fullerene Cage the structure of gd3n c2 22010 c78 departs from the isolated pentagon rule
Journal of the American Chemical Society, 2009Co-Authors: Christine M Beavers, Marilyn M Olmstead, Luis Echegoyen, Manuel N Chaur, Alan L BalchAbstract:An isomerically pure sample of Gd3N@C78 has been extracted from the carbon soot formed in the electric-arc generation of Fullerenes using hollow graphite rods packed with Gd2O3 and graphite powder under an atmosphere of helium and dinitrogen. Purification has been achieved by chromatographic methods and the product has been characterized by mass spectrometry, UV/vis absorption spectroscopy, and cyclic voltammetry. Although a number of endohedral Fullerenes have been found to utilize the D3h(5)-C78 Cage, comparison of the spectroscopic and electrochemical properties of the previously characterized Sc3N@D3h(5)-C78 with those of Gd3N@C78 reveals significant differences that indicate that these two endohedrals do not possess the same Cage structure. A single crystal X-ray diffraction study indicates that the Fullerene Cage does not follow the isolated pentagon rule (IPR) but has two equivalent sites where two pentagons abut. The endohedral has been identified as Gd3N@C2(22010)-C78. Two of the gadolinium atoms...
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Crystallographic characterization of isomer 2 of Er2@C82 and comparison with isomer 1 of Er2@C82.
Chemical Communications, 2002Co-Authors: Marilyn M Olmstead, S Stevenson, Harry C Dorn, Man Lee, Alan L BalchAbstract:The X-ray crystal structure of (Isomer 2 of Er2@C82). NiII(OEP).2(benzene) shows that the Fullerene Cage in Isomer 2 of Er2@C82 is the C3v isomer (82:8) and that the erbium ions are distributed over 23 interior sites with occupancies ranging from 0.25 to 0.03.
Alexey A. Popov - One of the best experts on this subject based on the ideXlab platform.
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Pyramidal TiTb 2 C cluster encapsulated within the popular Ih (7)-C 80 Fullerene Cage
Inorganica Chimica Acta, 2017Co-Authors: Fupin Liu, Alexey A. Popov, Fei Jin, Song Wang, Shangfeng YangAbstract:Abstract Interplay between the encapsulated cluster and Fullerene Cage is crucial for the stability of endohedral clusterFullerene. Herein we report the synthesis and isolation of a new entrant of carbido clusterFullerene, TiTb2C@Ih(7)-C80. The molecular structure of TiTb2C@Ih(7)-C80 was determined unambiguously by single crystal X-ray diffraction, featuring a pyramidal TiTb2C cluster encapsulated within the popular Ih(7)-C80 Cage. To our knowledge, TiTb2C represents the first pyramidal cluster found for carbido clusterFullerenes. On the basis of a comparative study with the reported TiM2C@Ih(7)-C80 (M = Sc, Lu) carbido clusterFullerenes and M3N@Ih(7)-C80 (M = Sc, Y and lanthanide) nitride clusterFullerenes, we tentatively determined the borderline of the sum of the three M-C(N) bond lengths of M3N/C for the encapsulated M3N/C cluster changing from planar to pyramidal geometry as 6.15–6.20 A. The electrochemical analyses on TiM2C@Ih(7)-C80 unraveled the self-adaptive structural transformations existing in the TiM2C@Ih(7)-C80 (M = Er, Y, Dy and Tb) based on their similar cluster-Cage strain evaluated through electrochemical measurements.
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Endohedral metal or a Fullerene Cage based oxidation? Redox duality of nitride clusterFullerenes CexM3−xN@C78–88 (x = 1, 2; M = Sc and Y) dictated by the enCaged metals and the carbon Cage size
Nanoscale, 2014Co-Authors: Yang Zhang, Alexey A. Popov, Lothar DunschAbstract:Redox behavior of endohedral metalloFullerenes, in particular their oxidation process, can be classified as a Fullerene-based or endohedral species-based process according to the mechanism of the electron transfer. Here we report on the phenomenon of the strain-driven electrochemical behavior achieved by encapsulating the cerium-containing clusters into a series of carbon Cages ranging from C78 to C88. The Ce-based mixed metal nitride clusterFullerenes CexM3−xN@C2n (x = 1, 2; M = Sc or Y; 2n = 78–88) were synthesized and characterized. The magnitude of the inherent strain caused by the limited inner space of the carbon Cage for the relatively large nitride clusters can be varied by choosing different scaffold metals (Sc, Lu, or Y) to tailor the size of the enCaged CexM3−xN cluster and by matching the nitride cluster with different Fullerene Cages in the size range from C78 to C88. The redox properties of CexM3−xN@C2n were investigated by cyclic and square wave voltammetry. The mechanism of the electrochemical oxidation of Ce-based mixed metal nitride clusterFullerenes, in particular whether the Fullerene-based oxidation or the CeIII → CeIV process is observed, is found to be dependent on the scaffold metal and the size of the Fullerene Cage. The endohedral oxidation of CeIII to CeIV was observed for a number of compounds as revealed by the negative shift of their oxidation potentials with respect to the values measured for the non-Ce analogues. Experimental studies are supported by DFT calculations. We conclude that the prerequisites for the Ce-based endohedral oxidation process are suitable inherent cluster-Cage strain and sufficiently high oxidation potential of the Fullerene Cage.
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A multi-state single-molecule switch actuated by rotation of an encapsulated cluster within a Fullerene Cage
Chemical Physics Letters, 2012Co-Authors: Tian Huang, Shangfeng Yang, Jin Zhao, Min Feng, Alexey A. Popov, Lothar Dunsch, Hrvoje PetekAbstract:We demonstrate a single-molecule switch based on tunneling electron-driven rotation of a triangular Sc3N cluster within an icosahedral C80 Fullerene Cage among three pairs of enantiomorphic configurations. Scanning tunneling microscopy imaging of switching within single molecules and electronic structure theory identify the conformational isomers and their isomerization pathways. Bias-dependent action spectra and modeling identify the antisymmetric stretch vibration of Sc3N cluster to be the gateway for energy transfer from the tunneling electrons to the cluster rotation. Hierarchical switching of conductivity through the internal cluster motion among multiple stationary states while maintaining a constant shape, is advantageous for the integration of endohedral Fullerene-based single-molecule memory and logic devices into parallel molecular computing architectures.
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A molecular switch based on current-driven rotation of an encapsulated cluster within a Fullerene Cage.
Nano letters, 2011Co-Authors: Tian Huang, Shangfeng Yang, Jin Zhao, Min Feng, Alexey A. Popov, Lothar Dunsch, Hrvoje PetekAbstract:By scanning tunneling microscopy imaging and electronic structure theory, we investigate a single-molecule switch based on tunneling electron-driven rotation of a triangular Sc3N cluster within an icosahedral C80 Fullerene Cage among three pairs of enantiomorphic configurations. Bias-dependent action spectra and modeling implicate the antisymmetric stretch vibration of Sc3N cluster as the gateway for energy transfer from the tunneling electrons into the cluster rotation. Hierarchical switching of conductivity among multiple stationary states while maintaining a constant molecular shape, offers an advantage for the integration of endohedral Fullerene-based single-molecule switches into multiple logic state molecular devices.
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an endohedral redox system in a Fullerene Cage the ce based mixed metal cluster Fullerene lu2cen c80
Physical Chemistry Chemical Physics, 2010Co-Authors: Lin Zhang, Shangfeng Yang, Alexey A. Popov, Sabrina Klod, Peter Rapta, Lothar DunschAbstract:Redox reactions of endohedral Fullerenes, and especially their oxidation, usually result in a change of the redox state of the carbon Cage. Here we demonstrate that an oxidation of the endohedral species is possible bypassing the Fullerene Cage in an unprecedented reversible cascade electron transfer under anodic conditions. The first Ce-based non-scandium mixed-metal nitride clusterFullerene (NCF) Lu2CeN@C80(Ih) was synthesized and isolated. The electronic and vibrational properties of Lu2CeN@C80 are characterized by UV-vis-NIR and FTIR spectroscopies and the Cage structure of Lu2CeN@C80 is determined by 13C NMR spectroscopy to be C80(Ih). At room temperature the NMR peak positions are shifted from the normal values of the diamagnetic M3N@C80 NCFs because of the unpaired f-electron localized on the Ce atom in the Ce3+ state. The variable-temperature NMR study enabled the estimation of the diamagnetic terms in the 13C chemical shifts, which were found to be close to those of diamagnetic M3N@C80 NCFs. The electrochemical properties of Lu2CeN@C80 were investigated by cyclic and square wave voltammetry, revealing two electrochemically irreversible but chemically reversible reduction steps and one reversible oxidation step. As the oxidation potential is significantly less positive than that in all other M3N@C80 NCFs, we conclude that an oxidation of the endohedral Ce occurs with the formation of Lu2CeIVN@C80+, the first endohedral metalloFullerene species with the tetra-valent cerium atom. This hypothesis is also supported by DFT calculations.
