621 results on '"Takeshi Akasaka"'
Search Results
2. Crystallographic Characterization of <scp> Lu 2 O </scp> @ C s (6)‐ <scp> C 82 </scp> and <scp> Er 2 O </scp> @ C s (6)‐ <scp> C 82 </scp> : The Role of Metal Species on Cluster Configuration †
- Author
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Pengwei Yu, Haocheng Mei, Shuaifeng Hu, Changwang Pan, Wangqiang Shen, Pengyuan Yu, Kun Guo, Yunpeng Xie, Takeshi Akasaka, Lipiao Bao, and Xing Lu
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General Chemistry - Published
- 2023
3. Photoreactions of Sc3N@C80 with Disilirane, Silirane, and Digermirane: A Photochemical Method to Separate Ih and D5h Isomers
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Masahiro Kako, Kyosuke Miyabe, Shinpei Fukazawa, Shinji Kanzawa, Masanori Yasui, Michio Yamada, Yutaka Maeda, Zdeněk Slanina, Filip Uhlík, Ludwik Adamowicz, Ilias Papadopoulos, Dirk M. Guldi, Makoto Furukawa, Shigeru Nagase, and Takeshi Akasaka
- Subjects
ddc:540 ,metallofullerene ,Sc3N@C80 ,disilirane ,silirane ,digermirane ,density functional theory ,photophysics - Abstract
Under photoirradiation, Sc3N@Ih-C80 reacted readily with disilirane 1, silirane 4, and digermirane 7 to afford the corresponding 1:1 adducts, whereas Sc3N@D5h-C80 was recovered without producing those adducts. Based on these results, we described a novel method for the exclusive separation of Ih and D5h isomers of Sc3N@C80. The method includes three procedures: selective derivatization of Sc3N@Ih-C80 using 1, 4, and 7, facile HPLC separation of pristine Sc3N@D5h-C80 and Sc3N@Ih-C80 derivatives, and thermolysis of Sc3N@Ih-C80 derivatives to collect pristine Sc3N@Ih-C80. In addition, laser flash photolysis experiments were conducted to elucidate the reaction mechanism. Decay of the transient absorption of 3Sc3N@Ih-C80* was observed to be enhanced in the presence of 1, indicating the quenching process. When Sc3N@D5h-C80 was used, the transient absorption was much less intensive. Therefore, the quenching of 3Sc3N@D5h-C80* by 1 could not be confirmed. Furthermore, we applied time-dependent density functional theory (TD-DFT) calculations of the photoexcited states of Sc3N@C80 to obtain insights into the reaction mechanism.
- Published
- 2022
4. Ultraviolet Photodetectors Based on Dimetallofullerene Lu2@Cs(6)-C82 Nanorods
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Ting Xu, Hong Yin, Pengwei Yu, Zhimin He, Ning Chen, Wangqiang Shen, Mingqiang Zhu, Takeshi Akasaka, and Xing Lu
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General Materials Science - Published
- 2022
5. Defective porous carbon microrods derived from fullerenes (C70) as high-performance electrocatalysts for the oxygen reduction reaction
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Zhimin He, Peng Wei, Ting Xu, Ziqian Guo, Jiantao Han, Takeshi Akasaka, Kun Guo, and Xing Lu
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General Materials Science - Abstract
Fullerene (C70) molecules are assembled into microrods, and calcination breaks the carbon cages into defect-rich porous carbon microrods that show excellent ORR performance, comparable to commercial Pt/C.
- Published
- 2022
6. Morphology Engineering of Fullerene[C 70 ] Microcrystals: From Perfect Cubes, Defective Hoppers to Novel Cruciform‐Pillars
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Wangqiang Shen, Ning Chen, Xing Lu, Zhimin He, Takeshi Akasaka, Ting Xu, and Pengwei Yu
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Photoluminescence ,Fullerene ,010405 organic chemistry ,Chemistry ,Organic Chemistry ,General Chemistry ,010402 general chemistry ,01 natural sciences ,Catalysis ,0104 chemical sciences ,law.invention ,Solvent ,chemistry.chemical_compound ,Surface-area-to-volume ratio ,Chemical engineering ,law ,Molecular symmetry ,Molecule ,Crystallization ,Mesitylene - Abstract
Controlled crystallization of fullerene molecules into ordered molecular assemblies is important for their applications. However, the morphology engineering of fullerene[C70 ] assemblies is challenging, and complicated architectures have rarely been reported due to the low molecular symmetry of C70 molecules, which makes their crystallization difficult to control and the low production yield as well. Herein, with the assistance of solvent intercalation, a general reprecipitation approach is reported to prepare morphologically controllable C70 microcrystals with mesitylene as a good solvent and n-propanol as a poor solvent in one solvent system without replacing specific solvents. A series of C70 microcrystals with high uniformity from perfect cubes and defective hoppers to novel cruciform-pillars are obtained by intentionally tuning C70 concentration and the volume ratio of mesitylene to n-propanol. Among them, novel cruciform-pillar-shaped microcrystals are obtained for the first time by further decreasing the amount of mesitylene in the solvent-intercalated microcrystals. Notably, the C70 concentration is a key parameter for the selective growth of C70 hopper, rather than the volume ratio of mesitylene to n-propanol. Interestingly, the hopper-shaped microcrystals exhibit excellent photoluminescence properties relative to those of cubes and cruciform-pillars owing to the enhanced light absorption, proving their potential applications in optoelectronic devices. This study offers new insights into the morphology-controlled synthesis of other micro/nanostructured organic microcrystals and the fine tuning of photoluminescence properties of organic crystals.
- Published
- 2021
7. Unexpected formation of 1,2- and 1,4-bismethoxyl Sc3N@Ih-C80 derivatives via regioselective anion addition: an unambiguous structural identification and mechanism study
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Xing Lu, Laura Abella, Su-Yuan Xie, Antonio Rodríguez-Fortea, Fang-Fang Li, Yajing Hu, Yang-Rong Yao, Josep M. Poblet, Takeshi Akasaka, Qianyan Zhang, Ao Yu, Xuechen Liu, Ping Peng, and Xiao-Ming Xie
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Chemistry ,Reaction mechanism ,chemistry.chemical_compound ,chemistry ,Tetrabutylammonium hydroxide ,Reagent ,Radical ,Metallofullerene ,Regioselectivity ,General Chemistry ,Electrochemistry ,Combinatorial chemistry ,Adduct - Abstract
An attempt to achieve heterocyclic cycloadducts of Sc3N@Ih-C80via reaction with Ph2C Created by potrace 1.16, written by Peter Selinger 2001-2019 O, PhC Created by potrace 1.16, written by Peter Selinger 2001-2019 CPh or PhCN in the presence of tetrabutylammonium hydroxide (TBAOH) stored in CH3OH led to the formation of the unexpected bismethoxyl adducts of Sc3N@Ih-C80 (1 and 2). Further studies reveal that TBAOH in CH3OH can boost the CH3O− addition efficiently, regardless of the presence of other reagents. Single-crystal X-ray diffraction results firmly assign the molecular structures of 1 and 2 as respective 1,4- and 1,2-bismethoxyl adducts, and reveal unusual relationships between the internal Sc3N cluster and the addition modes, in addition to the unusual packing mode in view of the orientation of the methoxyl groups. Electrochemical results demonstrate smaller electrochemical gaps for 1 and 2, relative to that of Sc3N@Ih-C80, confirming their better electroactive properties. Finally, a plausible reaction mechanism involving anion addition and a radical reaction was proposed, presenting new insights into the highly selective reactions between the methoxyl anion and metallofullerenes. 1 and 2 represent the first examples of methoxyl derivatives of metallofullerenes. This work not only presents a novel and facile strategy for the controllable synthesis of alkoxylated metallofullerene derivatives, but also provides new non-cycloadducts for the potential applications of EMFs., An attempt to achieve heterocyclic cycloadducts of Sc3N@Ih-C80via reaction with Ph2CO, PhCCPh or PhCN in the presence of tetrabutylammonium hydroxide (TBAOH) stored in CH3OH led to the formation of the unexpected bismethoxyl adducts of Sc3N@Ih-C80 (1 and 2).
- Published
- 2021
8. H2O·HF@C70: Encapsulation Energetics and Thermodynamics
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Zdeněk Slanina, Filip Uhlík, Xing Lu, Takeshi Akasaka, and Ludwik Adamowicz
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Inorganic Chemistry - Abstract
This report deals with the quantum-chemical evaluation of the energetics and thermodynamics of the simultaneous encapsulation of HF and H2O by the IPR (isolated pentagon rule) C70 fullerene cage, yielding H2O·HF@C70 species which were synthesized and characterized recently, thus further expanding the family of fullerene endohedrals with non-metallic encapsulates. The structures were optimized at the DFT (density functional theory) M06-2X/6-31++G** level. The encapsulation energetics were further refined by the advanced B2PLYPD/6-31++G** and B2PLYPD/6-311++G** methods. After enhancement of the B2PLYPD/6-311++G** encapsulation energy for the BSSE and steric corrections, the encapsulation energy gain was obtained, as 26 kcal/mol. The equilibrium encapsulation thermodynamics were described using the M06-2X/6-31++G** partition functions. The results correspond to our previous evaluations for the water dimer encapsulation by C84 cages.
- Published
- 2023
9. Radical Reaction and Photoreaction
- Author
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Yutaka Maeda, Shigeru Nagase, and Takeshi Akasaka
- Published
- 2022
10. Calculated relative populations for the Eu@C84 isomers
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Zdeněk Slanina, Xing Lu, Takeshi Akasaka, Lipiao Bao, Filip Uhlík, and Ludwik Adamowicz
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Physics ,Organic Chemistry ,Thermodynamics ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Potential energy ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Gibbs free energy ,symbols.namesake ,symbols ,General Materials Science ,Physical and Theoretical Chemistry ,0210 nano-technology - Abstract
Relative populations of eight low-potential-energy IPR (isolated-pentagon-rule) isomers of Eu@C84 are computed using the Gibbs energy based on the B2PLYPD/SDD potential energy. The calculations agr...
- Published
- 2020
11. Crystallographic Characterization of Ti2C2@D3h(5)-C78, Ti2C2@C3v(8)-C82, and Ti2C2@Cs(6)-C82: Identification of Unsupported Ti2C2 Cluster with Cage-Dependent Configurations
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Debo Hao, Le Yang, Lipiao Bao, Peng Jin, Xing Lu, Hongyun Fang, Takeshi Akasaka, Pengyuan Yu, and Wangqiang Shen
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chemistry.chemical_classification ,Fullerene ,Chemistry ,Metallic clusters ,chemistry.chemical_element ,Coordination complex ,Characterization (materials science) ,Inorganic Chemistry ,Crystallography ,Physics::Atomic and Molecular Clusters ,Cluster (physics) ,Physics::Chemical Physics ,Physical and Theoretical Chemistry ,Cage ,Titanium - Abstract
Fullerene cages are ideal hosts to encapsulate otherwise unstable metallic clusters to form endohedral metallofullerenes (EMFs). Herein, a novel Ti2C2 cluster with two titanium atoms bridged by a C...
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- 2020
12. Eu@C86 isomers: Calculated relative populations
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Xing Lu, Zdeněk Slanina, Filip Uhlík, Ludwik Adamowicz, Lipiao Bao, and Takeshi Akasaka
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Physics ,Organic Chemistry ,Thermodynamics ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Gibbs free energy ,symbols.namesake ,symbols ,General Materials Science ,Density functional theory ,Physical and Theoretical Chemistry ,0210 nano-technology - Abstract
Relative populations of four energy-lowest IPR (isolated-pentagon-rule) isomers of Eu@C86 are computed using the Gibbs energy based on characteristics from density functional theory calculations (M...
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- 2020
13. Crystallographic Characterization of Er2C2@C80–88: Cluster Stretching with Cage Elongation
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Shuaifeng Hu, Yunpeng Xie, Masahiro Ehara, Xing Lu, Pei Zhao, Takeshi Akasaka, and Wangqiang Shen
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Inorganic Chemistry ,Crystallography ,010405 organic chemistry ,Chemistry ,Cluster (physics) ,Physical and Theoretical Chemistry ,Elongation ,010402 general chemistry ,Cage ,01 natural sciences ,0104 chemical sciences ,Carbide ,Characterization (materials science) - Abstract
Six dierbium carbide endohedral metallofullerenes have been synthesized and chromatographically isolated. Single-crystal X-ray diffractometry unambiguously ascertains their structures as Er2C2@C2v(...
- Published
- 2020
14. Metal-encapsulation induces a highly regioselective Bingel–Hirsch reaction of the labile Y@Cs(6)-C82
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Wangqiang Shen, Bing Yu, Xing Lu, Hailin Cong, Le Yang, Peng Jin, Bo Li, and Takeshi Akasaka
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Metals and Alloys ,chemistry.chemical_element ,Regioselectivity ,General Chemistry ,Yttrium ,Catalysis ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Metal ,Crystallography ,chemistry ,visual_art ,Atom ,Materials Chemistry ,Ceramics and Composites ,visual_art.visual_art_medium ,Molecule ,Molecular orbital ,Spin density ,Cage - Abstract
The chemical properties of a prototypical labile mono-EMF, Y@Cs(6)-C82, have been systematically disclosed for the first time via a Bingel–Hirsch reaction. Three mono-adduct isomers, namely, 2a, 2b and 2c out of 44 possibilities for the Y@Cs(6)-C82 cage have been readily isolated, demonstrating surprisingly high regioselectivity. Crystallographic results of 2b unambiguously confirm its molecular structure with a singly bonded bromomalonate group attached onto the Cs(6)-C82 cage. Further computational results rationalize that the high regioselectivity is a consequence of the localization of high spin density and large frontier molecular orbital distribution on the corresponding carbon atoms stemming from the encapsulation of an yttrium atom into the low-symmetry Cs(6)-C82 cage with three-electron transfer from the metal to the cage.
- Published
- 2020
15. Defective porous carbon microrods derived from fullerenes (C
- Author
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Zhimin, He, Peng, Wei, Ting, Xu, Ziqian, Guo, Jiantao, Han, Takeshi, Akasaka, Kun, Guo, and Xing, Lu
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Disrupting the integrity of the sp
- Published
- 2021
16. Eu@C88 Isomers: Calculated Relative Populations
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Filip Uhlík, Zdeněk Slanina, Lipiao Bao, Takeshi Akasaka, Xing Lu, and Ludwik Adamowicz
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chemical properties of electronic materials ,theory and modelling ,nanoclusters ,fullerenes ,electron devices ,nanoscale materials ,Electronic, Optical and Magnetic Materials - Abstract
Relative populations of three energy-lowest IPR (isolated-pentagon-rule) isomers of Eu@C88 are computed using the Gibbs energy based on characteristics from density functional theory and MP2 calculations (M06-2X/3-21G∼SDD entropy term, and the MP2=FU/6-31G*∼SDD or B2PLYPD=FU/6-31 + G*∼SDD energetics). The calculations predict coexistence of three isomers, in agreement with extraction using a polar solvent, and offer a possible explanation why the Eu@C 2(27)-C88 species should prevail with a non-polar solvent. Role of extraction solvents and catalysis is thus pointed out.
- Published
- 2022
17. Crystallographic and Theoretical Investigations of Er 2 @C 2 n (2 n= 82, 84, 86): Indication of Distance‐Dependent Metal–Metal Bonding Nature
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Yunpeng Xie, Peng Jin, Takeshi Akasaka, Wangqiang Shen, Shuaifeng Hu, Xing Lu, Le Yang, and Guang-Xiong Duan
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chemistry.chemical_classification ,Fullerene chemistry ,010405 organic chemistry ,Organic Chemistry ,General Chemistry ,Electronic structure ,Electron acceptor ,010402 general chemistry ,01 natural sciences ,Catalysis ,0104 chemical sciences ,Crystallography ,chemistry ,Chemical bond ,X-ray crystallography ,Molecule ,Natural bond orbital ,Metallic bonding - Abstract
Successful isolation and characterization of a series of Er-based dimetallofullerenes present valuable insights into the realm of metal-metal bonding. These species are crystallographically identified as Er2 @Cs (6)-C82 , Er2 @C3v (8)-C82 , Er2 @C1 (12)-C84 , and Er2 @C2v (9)-C86 , in which the structure of the C1 (12)-C84 cage is unambiguously characterized for the first time by single-crystal X-ray diffraction. Interestingly, natural bond orbital analysis demonstrates that the two Er atoms in Er2 @Cs (6)-C82 , Er2 @C3v (8)-C82 , and Er2 @C2v (9)-C86 form a two-electron-two-center Er-Er bond. However, for Er2 @C1 (12)-C84 , with the longest Er⋅⋅⋅Er distance, a one-electron-two-center Er-Er bond may exist. Thus, the difference in the Er⋅⋅⋅Er separation indicates distinct metal bonding natures, suggesting a distance-dependent bonding behavior for the internal dimetallic cluster. Additionally, electrochemical studies suggest that Er2 @C82-86 are good electron donors instead of electron acceptors. Hence, this finding initiates a connection between metal-metal bonding chemistry and fullerene chemistry.
- Published
- 2019
18. Calculations of the relative populations of Lu@C82 isomers
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Xing Lu, Ludwik Adamowicz, Takeshi Akasaka, Filip Uhlík, Wangqiang Shen, and Zdeněk Slanina
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Physics ,Organic Chemistry ,Thermodynamics ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Gibbs free energy ,symbols.namesake ,Physics::Atomic and Molecular Clusters ,symbols ,General Materials Science ,Density functional theory ,Physics::Chemical Physics ,Physical and Theoretical Chemistry ,0210 nano-technology - Abstract
Relative populations of five IPR (isolated-pentagon-rule) isomers of Lu@C82 are computed using the Gibbs energy based on characteristics from density functional theory calculations (B3LYP/6...
- Published
- 2019
19. Calculated relative populations for the Eu@C82 isomers
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Lipiao Bao, Takeshi Akasaka, Ludwik Adamowicz, Xing Lu, Zdeněk Slanina, and Filip Uhlík
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Chemistry ,Energetics ,General Physics and Astronomy ,Thermodynamics ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Gibbs free energy ,symbols.namesake ,symbols ,Density functional theory ,Physical and Theoretical Chemistry ,Solubility ,0210 nano-technology - Abstract
Relative populations of four IPR (isolated-pentagon-rule) isomers of Eu@C82 are computed using the Gibbs energy based on characteristics from density functional theory calculations (M06-2X/6-31G∗∼SDD entropy term, M06-2X/6-31+G∗∼SDD or B2PLYPD/6-31G∗∼SDD energetics). Only the species observed by now also show significant calculated populations. A role of solubility in different solvents and/or composition of the arc electrodes could explain variability in the observed populations.
- Published
- 2019
20. Regioselective Coordination of Re2(CO)10 to Y@C2v(9)-C82: An Unprecedented η1 Complex Stabilized by Intramolecular Electron Transfer
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Lipiao Bao, Yunpeng Xie, Xing Lu, Takeshi Akasaka, Zdenek Slanina, and Changwang Pan
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Inorganic Chemistry ,Electron transfer ,010405 organic chemistry ,Chemistry ,Intramolecular force ,Organic Chemistry ,Regioselectivity ,Physical and Theoretical Chemistry ,010402 general chemistry ,Photochemistry ,01 natural sciences ,0104 chemical sciences - Abstract
The prototypical η1-coordinated complexes of endohedral metallofullerenes (EMFs) have never been reported because of their low stability. Herein, we have developed a highly efficient radical-coupli...
- Published
- 2019
21. Calculations of the Lu3N@C80 two-isomer equilibrium
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Ludwik Adamowicz, Filip Uhlík, Takeshi Akasaka, Lai Feng, Zdeněk Slanina, and Xing Lu
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Materials science ,Computational chemistry ,Organic Chemistry ,General Materials Science ,02 engineering and technology ,Physical and Theoretical Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,0210 nano-technology ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Encapsulation (networking) - Abstract
Computations of the relative concentrations are reported for the two isomers of Lu3N@C80 experimentally known, i.e., produced by encapsulation into the isolated-pentagon-rule (IPR) C80 cages with I...
- Published
- 2019
22. Isolation and Structural Characterization of Er@C2v(9)-C82 and Er@Cs(6)-C82: Regioselective Dimerization of a Pristine Endohedral Metallofullerene Induced by Cage Symmetry
- Author
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Takeshi Akasaka, Shuaifeng Hu, Yunpeng Xie, Filip Uhlík, Tong Liu, Wangqiang Shen, Wen-Huan Huang, Zdeněk Slanina, and Xing Lu
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010405 organic chemistry ,Regioselectivity ,Electronic structure ,010402 general chemistry ,Electrochemistry ,01 natural sciences ,0104 chemical sciences ,law.invention ,Inorganic Chemistry ,Crystallography ,chemistry.chemical_compound ,Monomer ,chemistry ,law ,Metallofullerene ,Atom ,Density functional theory ,Physical and Theoretical Chemistry ,Crystallization - Abstract
Two Er@C82 isomers have been isolated and unambiguously characterized as Er@ C2 v(9)-C82 and Er@ C s(6)-C82, respectively, by single-crystal X-ray diffraction. Er@ C s(6)-C82 is identified as a dimeric structure in the crystalline state, but dimerization does not occur for Er@ C2 v(9)-C82 under identical crystallization conditions, indicating a cage-symmetry-induced dimerization process. Density functional theory calculations reveal that the major unpaired spin resides on a special C atom of Er@ C s(6)-C82, which leads to regioselective dimerization. Calculations also found that the dimeric structure of Er@ C s(6)-C82·Ni(OEP) is much more stable than the two monomers, suggesting a thermodynamically favorable dimerization process. Vis-near-IR spectrometric and electrochemical results demonstrate that the electronic structure of Er@C82 isomers is Er3+@C823-, instead of the theoretically proposed Er2+@C822-.
- Published
- 2019
23. Crystallographic characterization of Y2C2n (2n = 82, 88–94): direct Y–Y bonding and cage-dependent cluster evolution
- Author
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Hongyun Fang, Zhan Wei, Yunpeng Xie, Peng Jin, Takeshi Akasaka, Lipiao Bao, Changwang Pan, Wangqiang Shen, Le Yang, and Xing Lu
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Materials science ,Valence (chemistry) ,Fullerene ,010405 organic chemistry ,Dimer ,chemistry.chemical_element ,General Chemistry ,Yttrium ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Ion ,Carbide ,chemistry.chemical_compound ,Crystallography ,chemistry ,Single bond ,Organometallic chemistry - Abstract
Direct yttrium–yttrium bonding has been a long-sought puzzle in organometallic chemistry to understand the catalytic processes that involve yttrium. Herein, we report the first crystallographic authentication of direct Y–Y bonding inside the hollow cavity of fullerene cages by forming endohedral metallofullerenes (EMFs). Based on an efficient separation/purification process, which involves Lewis-acid treatment and HPLC separation, we have obtained sufficient amounts of a series of Y2C2n (2n = 82, 88–94) isomers for systematic studies. The unambiguous single-crystal X-ray diffraction (XRD) crystallographic results show that two of them are di-EMFs, namely Y2@Cs(6)-C82 and Y2@C3v(8)-C82, in which the long-sought Y–Y single bond between the two divalent yttrium ions is experimentally confirmed for the first time. In contrast, all the other EMFs with relatively large cages are carbide cluster metallofullerenes (CCMFs), namely, Y2C2@Cs(15)-C86, Y2C2@C1(26)-C88, Y2C2@C2(41)-C90 and Y2C2@C2(61)-C92. Consistently, our computational results prove that these experimentally obtained EMFs are all abundant at the high temperatures for fullerene formation (∼1500–3000 K) due to the strong coordination ability of yttrium ions, which enables the formation of either direct Y–Y bonds (for Y2@Cs(6)-C82 and Y2@C3v(8)-C82) or the inclusion of a C2-unit (in Y2C2@Cs(15)-C86, Y2C2@C1(26)-C88, Y2C2@C2(41)-C90 and Y2C2@C2(61)-C92). Our results suggest that metal atoms such as yttrium tend to adopt a low valence state during the arc-discharge process because of the presence of the highly reductive carbon plasma in the chamber, enabling the formation of an Y2 dimer with direct Y–Y bonding in small cages like C82.
- Published
- 2019
24. Computational Modeling of the Ce@C82 Metallofullerene Isomeric Composition
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Xing Lu, Takeshi Akasaka, Zdeněk Slanina, Filip Uhlík, and Ludwik Adamowicz
- Subjects
chemistry.chemical_compound ,Materials science ,Chemical engineering ,chemistry ,Metallofullerene ,Composition (combinatorics) ,Electronic, Optical and Magnetic Materials - Published
- 2019
25. Crystallographic characterization of Er3N@C2n (2n = 80, 82, 84, 88): the importance of a planar Er3N cluster
- Author
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Shuaifeng Hu, Takeshi Akasaka, Yunpeng Xie, Wangqiang Shen, Masahiro Ehara, Wen-Huan Huang, Pei Zhao, Pengyuan Yu, and Xing Lu
- Subjects
Diffraction ,Materials science ,Band gap ,02 engineering and technology ,Nitride ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrochemistry ,01 natural sciences ,Redox ,0104 chemical sciences ,Crystallography ,Cluster (physics) ,General Materials Science ,Cyclic voltammetry ,0210 nano-technology ,HOMO/LUMO - Abstract
A series of Er-based nitride clusterfullerenes (NCFs), Er3N@C80–88, have been successfully synthesized and isolated. In particular, Er3N@Ih(7)-C80, Er3N@D5h(6)-C80, Er3N@C2v(9)-C82, Er3N@Cs(51365)-C84, and Er3N@D2(35)-C88 have been characterized by single-crystal X-ray diffraction (XRD) for the first time. The planar configuration of the inserted Er3N cluster is identified unambiguously and the Er–N distances increase in accordance with cage expansion to maintain strong metal–cage interactions. Additionally, the electrochemical properties of the Er3N@C80–88 series are studied by means of cyclic voltammetry. It is found that the first reduction potentials are roughly similar for all compounds under study, while the first oxidation potentials are cathodically shifted along with the increase of the cage size in the Er3N@C2n (2n = 80, 84, 86, 88) series, leading to a decrease in the corresponding electrochemical band gaps. Nevertheless, for Er3N@C2v(9)-C82, a good electron donating ability is manifested by its relatively small first oxidation potential, which results from the relatively higher energy level of the highest occupied molecular orbital. The redox behaviors observed in such Er3N-based NCFs may promise their great potential applications in donor–acceptor systems.
- Published
- 2019
26. Crystallographic characterization of Lu2C2n (2n = 76–90): cluster selection by cage size
- Author
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Wangqiang Shen, Peng Jin, Shuaifeng Hu, Le Yang, Takeshi Akasaka, Xing Lu, Yunpeng Xie, and Lipiao Bao
- Subjects
Materials science ,010405 organic chemistry ,chemistry.chemical_element ,General Chemistry ,010402 general chemistry ,01 natural sciences ,Lutetium ,0104 chemical sciences ,Ion ,Carbide ,Crystallography ,chemistry ,Cluster (physics) ,Single bond ,Molecule ,Valence electron ,Cage - Abstract
The successful isolation and unambiguous crystallographic assignment of a series of lutetium-containing endohedral metallofullerenes (EMFs), Lu2C2n (2n = 76, 78, 80, 84, 86, 88, 90), reveal an unrecognized decisive effect of the cage size on the configuration of the encapsulated clusters. The molecular structures of these compounds are unambiguously assigned as Lu2@Td(2)-C76, Lu2@D3h(5)-C78, Lu2@C2v(5)-C80, Lu2@C2v(7)-C84, Lu2@Cs(8)-C86, Lu2@Cs(15)-C86, Lu2@C1(26)-C88, Lu2C2@C2v(9)-C86, Lu2C2@Cs(32)-C88 and Lu2C2@D2(35)-C88. Specifically, when the cage is relatively small, Lu2@C2n (2n = 76–86) are all dimetallofullerenes (di-EMFs) and a Lu–Lu single bond could be formed between the two lutetium ions inside the cages. However, when the cage expands further, the valence electrons forming the possible Lu–Lu bond donate to a readily inserted C2-unit, resulting in the formation of carbide EMFs, Lu2C2@C2n (2n = 86, 88). Consistently, our theoretical results reveal that all these EMFs are thermodynamically favorable isomers. Thus the comprehensive characterization of the series of Lu2C76–90 isomers and the overall agreement between the experimental and theoretical results reveal for the first time that the exact configuration of the internal metallic cluster is determined by the cage size, taking a solid step towards the controlled synthesis of novel hybrid molecules which may have potential applications as building blocks of single molecule devices.
- Published
- 2019
27. Functionalization of Fullerenes: Addition Reactions
- Author
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Takeshi Akasaka, Shigeru Nagase, and Michio Yamada
- Subjects
Addition reaction ,Fullerene ,Chemistry ,Surface modification ,Photochemistry - Published
- 2021
28. Radical reaction and Photoreaction
- Author
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Yutaka Maeda, Shigeru Nagase, and Takeshi Akasaka
- Published
- 2021
29. Metal-encapsulation induces a highly regioselective Bingel-Hirsch reaction of the labile Y@
- Author
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Wangqiang, Shen, Le, Yang, Bo, Li, Peng, Jin, Bing, Yu, Hailin, Cong, Takeshi, Akasaka, and Xing, Lu
- Abstract
The chemical properties of a prototypical labile mono-EMF, Y@Cs(6)-C82, have been systematically disclosed for the first time via a Bingel-Hirsch reaction. Three mono-adduct isomers, namely, 2a, 2b and 2c out of 44 possibilities for the Y@Cs(6)-C82 cage have been readily isolated, demonstrating surprisingly high regioselectivity. Crystallographic results of 2b unambiguously confirm its molecular structure with a singly bonded bromomalonate group attached onto the Cs(6)-C82 cage. Further computational results rationalize that the high regioselectivity is a consequence of the localization of high spin density and large frontier molecular orbital distribution on the corresponding carbon atoms stemming from the encapsulation of an yttrium atom into the low-symmetry Cs(6)-C82 cage with three-electron transfer from the metal to the cage.
- Published
- 2020
30. Crystallographic Characterization of Ti
- Author
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Pengyuan, Yu, Lipiao, Bao, Le, Yang, Debo, Hao, Peng, Jin, Wangqiang, Shen, Hongyun, Fang, Takeshi, Akasaka, and Xing, Lu
- Abstract
Fullerene cages are ideal hosts to encapsulate otherwise unstable metallic clusters to form endohedral metallofullerenes (EMFs). Herein, a novel Ti
- Published
- 2020
31. New Horizons in Chemical Functionalization of Endohedral Metallofullerenes
- Author
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Shigeru Nagase, Michael T. H. Liu, Takeshi Akasaka, and Michio Yamada
- Subjects
Pericyclic reaction ,New horizons ,Fullerene ,pericyclic reactions ,Pharmaceutical Science ,Review ,Electrochemistry ,Lanthanoid Series Elements ,Analytical Chemistry ,lcsh:QD241-441 ,chemistry.chemical_compound ,lcsh:Organic chemistry ,addition reactions ,Computational chemistry ,Drug Discovery ,Physical and Theoretical Chemistry ,Derivatization ,lanthanide ions ,Cycloaddition Reaction ,nanocarbon ,fullerene ,Organic Chemistry ,radicals ,endohedral metallofullerene ,Carbon ,carbenes ,chemistry ,Models, Chemical ,electrochemistry ,Chemistry (miscellaneous) ,Chemical functionalization ,chemical functionalization ,Molecular Medicine ,Quantum Theory ,Fullerenes - Abstract
This overview explains some new aspects of chemical functionalization of endohedral metallofullerenes (EMFs) that have been unveiled in recent years. After differences in chemical reactivity between EMFs and the corresponding empty fullerenes are discussed, cage-opening reactions of EMFs are examined. Then, the selective bisfunctionalization of EMFs is explained. Finally, single-bonding derivatization of EMFs is addressed. The diversity and applicability of the chemical functionalization of endohedral metallofullerenes are presented to readers worldwide.
- Published
- 2020
32. Crystallographic Characterization of Er
- Author
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Shuaifeng, Hu, Pei, Zhao, Wangqiang, Shen, Masahiro, Ehara, Yunpeng, Xie, Takeshi, Akasaka, and Xing, Lu
- Abstract
Six dierbium carbide endohedral metallofullerenes have been synthesized and chromatographically isolated. Single-crystal X-ray diffractometry unambiguously ascertains their structures as Er
- Published
- 2020
33. Gewinnung reaktiver Fullerene aus Ruß durch exohedrale Derivatisierung
- Author
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Takeshi Akasaka, Shigeru Nagase, and Michio Yamada
- Subjects
010405 organic chemistry ,Chemistry ,General Medicine ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences - Published
- 2018
34. Fullerene/cobalt porphyrin charge-transfer cocrystals: Excellent thermal stability and high mobility
- Author
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Peng Jin, Muqing Chen, Kazuhito Tsukagoshi, Takeshi Akasaka, Jun Zhou, Shushu Zheng, Junwen Zhong, Shu Seki, Xing Lu, and Wakana Matsuda
- Subjects
Electron mobility ,Materials science ,Fullerene ,Supramolecular chemistry ,chemistry.chemical_element ,Nanotechnology ,02 engineering and technology ,Thermal treatment ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Porphyrin ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Organic semiconductor ,chemistry.chemical_compound ,chemistry ,General Materials Science ,Thermal stability ,Electrical and Electronic Engineering ,0210 nano-technology ,Cobalt - Abstract
Although organic semiconductors with high mobility and thermal stability are particularly desirable for practical applications, facile methods for their development still remains a big challenge. In this work, a charge-transfer cocrystal based on fullerene (C70)/cobalt porphyrin supramolecular architecture was prepared by a solution-processable co-assembly strategy. This supramolecular architecture showed hole mobility as high as 4.21 cm2·V−1·s−1, and a relatively high mobility of 0.02 cm2·V−1·s−1 even after thermal treatment at 1,000 °C. Further studies confirmed the occurrence of charge-transfer from 5,10,15,20-tetrakis(4-methoxyphenyl)porphyrinato cobalt(II) (CoTMPP) to C70 and the paramagnetic character within the supramolecular system. These factors were found to be responsible for the aforementioned superior performances. Thus, a novel organic semiconductor has been reported in this work, which can be potentially used for next generation electronic devices. Furthermore, it has been demonstrated that charge-transfer co-crystallization is a powerful strategy for the rational design and construction of a broad class of new multifunctional organic co-crystalline materials.
- Published
- 2018
35. Cyclic water-trimer encapsulation into D2(22)-C84 fullerene
- Author
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Xing Lu, Shigeru Nagase, Zdeněk Slanina, Takeshi Akasaka, Ludwik Adamowicz, and Filip Uhlík
- Subjects
Crystallography ,Fullerene ,Materials science ,General Physics and Astronomy ,Trimer ,02 engineering and technology ,Physical and Theoretical Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,0210 nano-technology ,01 natural sciences ,Potential energy ,0104 chemical sciences - Abstract
The cyclic water-trimer encapsulations into D 2 (22)- C 84 fullerene are evaluated. The encapsulation energy is computed at the M06-2X/6-31++G∗∗ level and it is found that the trimer storage in C 84 yields the potential-energy gain of 10.4 kcal/mol. The encapsulated trimer can have two different forms, either the conformation known with the free gas-phase water trimer or the arrangement with the three non-hydrogen bonded H atoms on the same side of the O-O-O plane. The latter endohedral isomer is lower in the potential energy by 0.071 kcal/mol and forms about 57% of their equilibrium mixture at room temperature.
- Published
- 2018
36. Facile Access to Y2C2n (2n = 92–130) and Crystallographic Characterization of Y2C2@C1(1660)-C108: A Giant Nanocapsule with a Linear Carbide Cluster
- Author
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Hongyun Fang, Xing Lu, Takeshi Akasaka, Changwang Pan, Yunpeng Xie, Xianyong Yu, and Lipiao Bao
- Subjects
chemistry.chemical_classification ,Fullerene ,Materials science ,General Engineering ,General Physics and Astronomy ,Electron donor ,02 engineering and technology ,Electron acceptor ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrochemistry ,01 natural sciences ,0104 chemical sciences ,Carbide ,Metal ,Crystallography ,chemistry.chemical_compound ,chemistry ,visual_art ,Metallofullerene ,visual_art.visual_art_medium ,Cluster (physics) ,General Materials Science ,0210 nano-technology - Abstract
A series of giant metallofullerenes Y2C2n (2n = 92–130) have been successfully obtained through the treatment of the fraction enriched by 1,2-dichlorobenzene with SnCl4. Subsequent chromatographic separation gives a pure sample with a composition of Y2C110. Crystallographic results reveal that this endohedral takes the carbide form, namely Y2C2@C1(1660)-C108, representing as the largest metallofullerene that has been characterized by crystallography to date. Despite the disorder of the metal cluster, the major Y2C2 adopts a previously predicted linear configuration, indicating that the compression of the internal cluster by the cage is almost negligible in this giant cage. Electrochemical studies suggest that Y2C2@C1(1660)-C108 is a good electron donor instead of an electron acceptor.
- Published
- 2018
37. Er@C 82 as a Bifunctional Additive to the Spiro‐OMeTAD Hole Transport Layer for Improving Performance and Stability of Perovskite Solar Cells
- Author
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Shuaifeng Hu, Xiaoqin Ye, Wangqiang Shen, Takeshi Akasaka, Xing Lu, and Pengwei Yu
- Subjects
chemistry.chemical_compound ,Materials science ,chemistry ,Chemical engineering ,Energy conversion efficiency ,Energy Engineering and Power Technology ,Perovskite solar cell ,Hole transport layer ,Electrical and Electronic Engineering ,Bifunctional ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Perovskite (structure) - Published
- 2021
38. A computational characterization of CO@C60
- Author
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Zdeněk Slanina, Takeshi Akasaka, Shigeru Nagase, Ludwik Adamowicz, Filip Uhlík, and Xing Lu
- Subjects
Materials science ,Organic Chemistry ,General Materials Science ,Nanotechnology ,02 engineering and technology ,Physical and Theoretical Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,0210 nano-technology ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Encapsulation (networking) - Abstract
The hydrogen-peroxide encapsulation into C60 is evaluated using the DFT (M06-2X) and B2PLYPD as well MP2 calculations in the standard 6-31++G** and 6-311++G** basis sets. The H2O2 encapsulation is ...
- Published
- 2017
39. Computed stabilization for a giant fullerene endohedral: Y2C2@C1(1660)-C108
- Author
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Takeshi Akasaka, Ludwik Adamowicz, Xing Lu, Changwang Pan, Zdeněk Slanina, and Filip Uhlík
- Subjects
Fullerene ,Materials science ,Chemical physics ,General Physics and Astronomy ,02 engineering and technology ,Physical and Theoretical Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,0210 nano-technology ,01 natural sciences ,0104 chemical sciences - Abstract
The very recently prepared clusterfullerene Y2C2@ C 1 (1660)-C108 is computed and the observed structural features are confirmed, including the quasi-linear arrangement of the encapsulate and its near-triple CC bond. Its stability is explained by sizeable encapsulation energy. The endohedral stability is evaluated at both DFT and MP2 levels.
- Published
- 2018
40. Calculated Relative Thermodynamic Stabilities of the Gd@C82 Isomers
- Author
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Zdenek Slanina, Ludwik Adamowicz, Takeshi Akasaka, Filip Uhlík, and Xing Lu
- Subjects
Materials science ,Thermodynamics ,Electronic, Optical and Magnetic Materials - Abstract
Relative equilibrium populations of the IPR (isolated-pentagon-rule) isomers of Gd@C82 under the high-temperature synthetic conditions are calculated. The calculations are based on the Gibbs energy derived using characteristics from the density functional theory calculations (B3LYP/3-21G ∼ SDD entropy term, B2PLYPD/6-31+G* ∼ SDD energetics). In agreement with observations, Gd@C 2v (9)-C82 is the prevailing isomer while Gd@C s (c; 6)-C82 is predicted as a minor species.
- Published
- 2021
41. Stability issues in computational screening of carbon nanostructures: illustrations on La endohedrals
- Author
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Shigeru Nagase, Zdeněk Slanina, Ludwik Adamowicz, Filip Uhlík, Xing Lu, and Takeshi Akasaka
- Subjects
Carbon nanostructures ,Chemistry ,General Chemical Engineering ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Computational chemistry ,Modeling and Simulation ,General Materials Science ,0210 nano-technology ,Information Systems - Abstract
Three important stability problems frequently met in calculations of carbon nanostructures are outlined. The three relative-stability issues concern: isomeric carbon clusters, non-isomeric metallofullerenes differing in the number of the encapsulated metal atom yet placed in still isomeric carbon cages, and monometallofullerenes with different metals encapsulated in one selected carbon cage. The related computational approaches are illustrated with endohedrals based on La and its congeners located in , and cages, both IPR (isolated-pentagon rule) and non-IPR ones, evaluated using various DFT treatments. It is also concluded that among the La congeners, Ac can produce the second best encapsulation energy, just after La.
- Published
- 2017
42. Preparation, Structural Determination, and Characterization of Electronic Properties of [5,6]- and [6,6]-Carbosilylated Sc3 N@Ih -C80
- Author
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Yutaka Maeda, Takeshi Sugiura, Jing-Dong Guo, Masahiro Kako, Masanori Yasui, Takeshi Akasaka, Shigeru Nagase, Kyosuke Miyabe, and Michio Yamada
- Subjects
Fullerene ,010405 organic chemistry ,Chemistry ,Organic Chemistry ,Inorganic chemistry ,General Chemistry ,010402 general chemistry ,Electrochemistry ,01 natural sciences ,Biochemistry ,Decomposition ,Redox ,0104 chemical sciences ,Characterization (materials science) ,Adduct ,Computational chemistry ,Surface modification ,Isomerization - Abstract
Photochemical carbosilylation of Sc3 N@Ih -C80 with silirane 1 afforded two corresponding [5,6]-adducts, 2 and 3, and a [6,6]-adduct, 4. The structural and electronic properties of these products were characterized by means of spectroscopic, electrochemical, and theoretical methods. The structure of 2 was disclosed by means of single-crystal X-ray crystallographic analysis. Thermal isomerization of 3 to 2 was observed, whereas that of 2 to 3 proceeded less efficiently at 100 °C. Upon heating under the same conditions, adduct 4 underwent facile decomposition to afford Sc3 N@Ih -C80 , or isomerized into small amounts of 2 and 3. The relative stabilities of 2, 3, and 4 were rationalized through the results of theoretical calculations. In contrast, adducts 2, 3, and 4 were stable under the photolytic conditions employed for carbosilylation. The photochemical functionalization of Sc3 N@Ih -C80 represents a convenient synthetic method to obtain thermally labile fullerene-based products.
- Published
- 2017
43. Fullerene C70 as a Nanoflask that Reveals the Chemical Reactivity of Atomic Nitrogen
- Author
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Yuta Morinaka, Rui Zhang, Satoru Sato, Hidefumi Nikawa, Tatsuhisa Kato, Ko Furukawa, Michio Yamada, Yutaka Maeda, Michihisa Murata, Atsushi Wakamiya, Shigeru Nagase, Takeshi Akasaka, and Yasujiro Murata
- Subjects
0301 basic medicine ,03 medical and health sciences ,030104 developmental biology ,General Medicine ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences - Published
- 2017
44. Fullerene C70 as a Nanoflask that Reveals the Chemical Reactivity of Atomic Nitrogen
- Author
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Hidefumi Nikawa, Yuta Morinaka, Yutaka Maeda, Atsushi Wakamiya, Ko Furukawa, Shigeru Nagase, Yasujiro Murata, Satoru Sato, Takeshi Akasaka, Rui Zhang, Michihisa Murata, Michio Yamada, and Tatsuhisa Kato
- Subjects
Fullerene chemistry ,Fullerene ,010405 organic chemistry ,Chemistry ,Analytical chemistry ,chemistry.chemical_element ,General Chemistry ,010402 general chemistry ,Photochemistry ,Mass spectrometry ,01 natural sciences ,Nitrogen ,Catalysis ,0104 chemical sciences ,Physics::Atomic and Molecular Clusters ,Endohedral fullerene ,Molecule ,Reactivity (chemistry) ,Physics::Chemical Physics ,Spectroscopy - Abstract
To investigate the intrinsic reactivity of atomic nitrogen, which had previously been accomplished only by examining its decay in the gas phase using special equipment, a nitrogen atom was inserted into a series of molecule-encapsulating C60 and C70 fullerenes. Among the studied endofullerenes, H2 @C70 was able to encapsulate an additional nitrogen atom within the fullerene cage under radiofrequency plasma conditions. The product was analyzed by ESR spectroscopy and mass spectrometry in solution, which revealed that the nitrogen atom with a quartet ground state does not react but weakly interact with the H2 molecule, thus demonstrating the utility of such fullerenes as "nanoflasks".
- Published
- 2017
45. Diagnostic performance of 320-slice computed tomography coronary angiography for symptomatic patients in clinical practice
- Author
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Tadashi Wada, Shigeru Saito, Tomoyuki Tani, Masato Murakami, Futoshi Yamanaka, Shingo Mizuno, Koki Shishido, Kazuya Sugitatsu, Shinji Tanaka, Daisuke Hachinohe, Hidetaka Suenaga, Tomoki Ochiai, Saeko Takahashi, Yutaka Tanaka, Takeshi Akasaka, Kyosuke Furuhashi, Noriaki Moriyama, Junya Matsumi, and Kazuki Tobita
- Subjects
Male ,Coronary angiography ,medicine.medical_specialty ,Computed Tomography Angiography ,Provocation test ,Coronary Vasospasm ,Computed tomography ,Coronary Artery Disease ,030204 cardiovascular system & hematology ,Sensitivity and Specificity ,Angina Pectoris ,Coronary artery disease ,03 medical and health sciences ,0302 clinical medicine ,Japan ,Internal medicine ,Internal Medicine ,medicine ,Humans ,cardiovascular diseases ,030212 general & internal medicine ,Aged ,Retrospective Studies ,medicine.diagnostic_test ,business.industry ,Middle Aged ,medicine.disease ,Clinical Practice ,Coronary vasospasm ,Cohort ,Cardiology ,Ergonovine ,Female ,Radiology ,business - Abstract
Objective Multi-slice computed tomography (MSCT) coronary angiography has been reported as an effective alternative to invasive conventional coronary angiography (CCA) for the diagnosis of coronary artery disease (CAD). However, in previous reports, the diagnostic accuracy of MSCT has not been significant enough to be of benefit in symptomatic patients. The aim of this study was to identify the usefulness of 320-slice computed tomography coronary angiography (320-CTA) for symptomatic patients in terms of the diagnostic accuracy of 320-CTA and the prevalence of vasospastic angina pectoris (VSAP) within the study cohort. Methods We retrospectively analyzed 513 consecutive symptomatic patients with suspected CAD who had undergone 320-CTA and CCA. We determined the diagnostic accuracy of 320-CTA using CCA as the reference standard. Ergonovine provocation tests were performed on patients without significant coronary artery stenosis on CCA. Results Of the total cohort of 513 symptomatic patients, 39% had obstructive CAD. The patient based analysis of the accuracy of 320-CTA showed a sensitivity of 91.0%, a specificity of 71.0%, a positive predictive value of 66.5%, and a negative predictive value of 92.5%. Of the 314 symptomatic patients who did not have significant coronary artery stenosis on CCA, 58 (18%) were diagnosed with VSAP using ergonovine provocation tests. Discussion The negative and positive predictive values indicate that 320-CTA cannot replace CCA for symptomatic patients. Indeed, a combination of CCA and ergonovine provocation tests should be taken into consideration for symptomatic patients.
- Published
- 2017
46. Adamantylidene Addition to M 3 N@ I h ‐C 80 (M=Sc, Lu) and Sc 3 N@ D 5 h ‐C 80 : Synthesis and Crystallographic Characterization of the [5,6]‐Open and [6,6]‐Open Adducts
- Author
-
Takeshi Akasaka, Yutaka Maeda, Chiharu Saito, Toshiki Yamazaki, Satoru Sato, Yongfu Lian, Naomi Mizorogi, Filip Uhlík, Tsuneyuki Abe, Xing Lu, Mitsuaki Suzuki, Marilyn M. Olmstead, Alan L. Balch, Zdenek Slanina, Michio Yamada, and Shigeru Nagase
- Subjects
010405 organic chemistry ,Stereochemistry ,Chemistry ,Organic Chemistry ,Regioselectivity ,General Chemistry ,Nitride ,010402 general chemistry ,01 natural sciences ,Catalysis ,0104 chemical sciences ,Adduct ,Metal ,Crystallography ,visual_art ,Yield (chemistry) ,Atom ,visual_art.visual_art_medium - Abstract
Additions of adamantylidene (Ad) to M3 N@Ih -C80 (M=Sc, Lu) and Sc3 N@D5h -C80 have been accomplished by photochemical reactions with 2-adamantyl-2,3'-[3H]-diazirine (1). In M3 N@Ih -C80 , the addition led to rupture of the [6,6]- or [5,6]-bonds of the Ih -C80 cage, forming the [6,6]-open fulleroid as the major isomer and the [5,6]-open fulleroid as the minor isomer. In Sc3 N@D5h -C80 , the addition also proceeded regioselectively to yield three major isomeric Ad mono-adducts, despite the fact that there are nine types of C-C bonds in the D5h -C80 cage. The molecular structures of the seven Ad mono-adducts, including the positions of the encaged trimetallic nitride clusters, have been unambiguously determined through single-crystal XRD analyses. Furthermore, results have shown that stepwise addition of Ad to Lu3 N@Ih -C80 affords several Ad bis-adducts, two of which have been isolated and characterized. The X-ray structure of one bis-adduct clearly revealed that the second Ad addition took place at a [6,6]-bond close to an endohedral metal atom. Theoretical calculations have also been performed to rationalize the regioselectivity.
- Published
- 2017
47. Transradial Coronary Interventions for Complex Chronic Total Occlusions
- Author
-
Takuma Takada, Yutaka Tanaka, Futoshi Yamanaka, Shingo Mizuno, Kazuya Sugitatsu, Masato Murakami, Kazuki Tobita, Takeshi Akasaka, Tomoki Ochiai, Shigeru Saito, Koki Shishido, Saeko Takahashi, Noriaki Moriyama, and Junya Matsumi
- Subjects
medicine.medical_specialty ,business.industry ,medicine.medical_treatment ,Technical success ,Psychological intervention ,Percutaneous coronary intervention ,030204 cardiovascular system & hematology ,Surgery ,03 medical and health sciences ,0302 clinical medicine ,Internal medicine ,Angioplasty ,Occlusion ,Conventional PCI ,Cardiology ,Medicine ,030212 general & internal medicine ,Hemodialysis ,Cardiology and Cardiovascular Medicine ,business ,Cohort study - Abstract
Objectives The aims of this study were to assess whether the transradial approach can be applied to treat complex chronic total occlusion (CTO) and to determine the predictors of transradial percutaneous coronary intervention (PCI) failure. Background Consistent data on the outcomes of transradial PCI for treating CTO are scarce. Methods Consecutive patients who were not receiving hemodialysis and had undergone PCI for CTO were enrolled. The clinical and angiographic characteristics, procedural details, and outcomes of the transradial and transfemoral procedures were examined. Results In total, 280 and 305 CTO PCI procedures involved transradial and transfemoral access, respectively. The technical success rates did not significantly differ in the entire cohort analysis and the propensity score–matched analysis (74.6% vs. 72.5%; p = 0.51 and 70.6% vs. 73.3%; p = 0.57). When only cases with J-CTO (Multicenter Chronic Total Occlusion Registry of Japan) scores of ≥3 were examined, the transradial group had a significantly lower success rate than the transfemoral group (35.7% vs. 58.2%; p = 0.04). The use of guiding catheter size 20 mm (OR: 2.97; p Conclusions Transradial PCI for CTO may be feasible in noncomplex cases, although complex cases still pose a challenge. In cases of transradial PCI for CTO, if possible, guiding catheter size ≥7 F should be selected regardless of lesion morphology. Furthermore, the transfemoral approach should be preferentially considered for complex CTO, particularly in cases with calcification.
- Published
- 2017
48. D2d(23)-C84 versus Sc2C2@D2d(23)-C84: Impact of Endohedral Sc2C2 Doping on Chemical Reactivity in the Photolysis of Diazirine
- Author
-
Hiroki Kurihara, Satoru Sato, Makoto Hachiya, Yongfu Lian, Yukiko Tanabe, Yutaka Maeda, Takeshi Akasaka, Michio Yamada, Jing-Shuang Dang, Tsuneyuki Abe, Naomi Mizorogi, Mitsuaki Suzuki, Shigeru Nagase, and Xiang Zhao
- Subjects
010405 organic chemistry ,Chemistry ,Photodissociation ,Doping ,chemistry.chemical_element ,General Chemistry ,010402 general chemistry ,Photochemistry ,01 natural sciences ,Biochemistry ,Catalysis ,0104 chemical sciences ,Adduct ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,Diazirine ,Carbon - Abstract
We compared the chemical reactivity of D2d(23)-C84 and that of Sc2C2@D2d(23)-C84, both having the same carbon cage geometry, in the photolysis of 2-adamantane-2,3′-[3H]-diazirine, to clarify metal-atom doping effects on the chemical reactivity of the carbon cage. Experimental and computational studies have revealed that the chemical reactivity of the D2d(23)-C84 carbon cage is altered drastically by endohedral Sc2C2 doping. The reaction of empty D2d(23)-C84 with the diazirine under photoirradiation yields two adamantylidene (Ad) adducts. NMR spectroscopic studies revealed that the major Ad monoadduct (C84(Ad)-A) has a fulleroid structure and that the minor Ad monoadduct (C84(Ad)-B) has a methanofullerene structure. The latter was also characterized using X-ray crystallography. C84(Ad)-A is stable under photoirradiation, but it interconverted to C84(Ad)-B by heating at 80 °C. In contrast, the reaction of endohedral Sc2C2@D2d(23)-C84 with diazirine under photoirradiation affords four Ad monoadducts (Sc2C2@C...
- Published
- 2016
49. The Unanticipated Dimerization of Ce@C2v(9)-C82upon Co-crystallization with Ni(octaethylporphyrin) and Comparison with Monomeric M@C2v(9)-C82(M = La, Sc, and Y)
- Author
-
Yuta Takano, Michio Yamada, Takeshi Akasaka, Shigeru Nagase, Marilyn M. Olmstead, Mitsuaki Suzuki, Yongfu Lian, Filip Uhlík, Xing Lu, Alan L. Balch, Zdenek Slanina, Yutaka Maeda, and Satoru Sato
- Subjects
010405 organic chemistry ,Chemistry ,Dimer ,Organic Chemistry ,General Chemistry ,Crystal structure ,010402 general chemistry ,Ring (chemistry) ,01 natural sciences ,Catalysis ,0104 chemical sciences ,law.invention ,Bond length ,Metal ,chemistry.chemical_compound ,Crystallography ,Monomer ,law ,visual_art ,Endohedral fullerene ,visual_art.visual_art_medium ,Crystallization - Abstract
We report that Ce@C2v(9)-C82 forms a centrosymmetric dimer when co-crystallized with Ni(OEP) (OEP = octaethylporphyrin dianion). The crystal structure of {Ce@C2v(9)-C82}2⋅2[Ni(OEP)]⋅4 C6H6 shows that a new C−C bond with a bond length of 1.605(5) A connects the two cages. The high spin density of the singly occupied molecular orbital (SOMO) on the cage and the pyramidalization of the cage are factors that favor dimerization. In contrast, the treatment of Ni(OEP) with M@C2v(9)-C82 (M = La, Sc, and Y) results in crystallization of monomeric endohedral fullerenes. A systematic comparison of the X-ray structures of M@C2v(9)-C82 (M = Sc, Y, La, Ce, Gd, Yb, and Sm) reveals that the major metal site in each case is located at an off-center position adjacent to a hexagonal ring along the C2 axis of the C2v(9)-C82 cage. DFT calculations at the M06-2X level revealed that the positions of the metal centers in these metallofullerenes M@C2v(9)-C82 (M = Sc, Y, and Ce), as determined by single-crystal X-ray structure studies, correspond to an energy minimum for each compound.
- Published
- 2016
50. Crystallographic characterization of Er
- Author
-
Shuaifeng, Hu, Wangqiang, Shen, Pei, Zhao, Ting, Xu, Zdeněk, Slanina, Masahiro, Ehara, Xiang, Zhao, Yunpeng, Xie, Takeshi, Akasaka, and Xing, Lu
- Abstract
For endohedral metallofullerenes (EMFs), that is, fullerenes encapsulating metallic species, cage size is known to be an important factor for cluster configuration adoption; however, the impact of the cage shape on the cluster geometry fitting remains poorly understood. Herein, for the first time, four dierbium-carbide EMFs with C
- Published
- 2019
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