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Fullerene C60

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https://www.readbyqxmd.com/read/29660980/azabuckybowl-based-molecular-tweezers-as-c-60-and-c-70-receptors
#1
Motoki Takeda, Satoru Hiroto, Hiroki Yokoi, Sangsu Lee, Dongho Kim, Hiroshi Shinokubo
We designed and synthesized molecular tweezers consisted of nitrogen-embedded buckybowl subunits. The judicious choice of the covalent linkers modulated their binding strength with C60 or C70 in solution. Titration studies by optical and 1 H NMR analysis revealed a 1:1 composition of the resulting complexes. X-Ray diffraction analysis elucidated their solid-state structures in which two azabuckybowl units surround one molecule of fullerenes. The large association constants stabilize the complexes under redox reactions and purification process on silica-gel column chromatography...
April 17, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29658170/new-ordered-structure-of-amorphous-carbon-clusters-induced-by-fullerene-cubane-reactions
#2
Mingrun Du, Mingguang Yao, JiaJun Dong, Peng Ge, Qing Dong, Éva Kováts, Sándor Pekker, Shuanglong Chen, Ran Liu, Bo Liu, Tian Cui, Bertil Sundqvist, Bingbing Liu
As a new category of solids, crystalline materials constructed with amorphous building blocks expand the structure categorization of solids, for which designing such new structures and understanding the corresponding formation mechanisms are fundamentally important. Unlike previous reports, new amorphous carbon clusters constructed ordered carbon phases are found here by compressing C8 H8 /C60 cocrystals, in which the highly energetic cubane (C8 H8 ) exhibits unusual roles as to the structure formation and transformations under pressure...
April 15, 2018: Advanced Materials
https://www.readbyqxmd.com/read/29651501/fullerene-c-60-in-atmospheric-aerosol-and-its-relationship-to-combustion-processes
#3
Dolores Encinas, Zuriñe Gómez-de-Balugera
Fullerenes are emerging pollutants, and it is essential to determine and quantify these compounds to assess environmental risk and environmental flows. The goal of this work was to determine the fullerene C60 emission levels in the atmospheric aerosol and their relationship with combustion processes. To measure the concentration, a fullerene C60 extraction method with toluene was optimized in air samples using ultrasound, followed by analysis using high-pressure, liquid chromatography-diode array detector-mass spectrometry...
April 12, 2018: Archives of Environmental Contamination and Toxicology
https://www.readbyqxmd.com/read/29645035/electron-driven-spin-diffusion-supports-crossing-the-diffusion-barrier-in-mas-dnp
#4
Johannes J Wittmann, Michael Eckardt, Wolfgang Harneit, Björn Corzilius
Dynamic nuclear polarization (DNP) can be applied to enhance the sensitivity of solid-state NMR experiments by several orders of magnitude due to microwave-driven transfer of spin polarization from unpaired electrons to nuclei. While the underlying quantum mechanical aspects are sufficiently well understood on a microscopic level, the exact description of the large-scale spin dynamics, usually involving hundreds to thousands of nuclear spins per electron, is still lacking consensus. Generally, it is assumed that nuclear hyperpolarization can only be observed on nuclei which do not experience strong influence of the unpaired electrons and thus being significantly removed from the paramagnetic polarizing agents...
April 12, 2018: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29644372/fullerene-size-controls-the-selective-complexation-of-11-cpp-with-pristine-and-endohedral-fullerenes
#5
I González-Veloso, E M Cabaleiro-Lago, J Rodríguez-Otero
The ability of the carbon nanoring [11]cycloparaphenylene ([11]CPP) for coordinating fullerenes has been tested using a series of hosts, including the pristine fullerenes C60, C70, C76 and C78, the clusterfullerene Sc3N@C80, monometallic endofullerenes Y@C82 and Tm@C82, and dimetallic endofullerenes Y2@C82 and Lu2@C82. A systematic theoretical study employing dispersion corrected density functional methods has been carried out in order to explore the characteristics of the complexes and the strength of the interaction...
April 12, 2018: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29629562/a-polyaromatic-nano-nest-for-hosting-fullerenes-c-60-and-c-70
#6
Yihui Yang, Kunmu Cheng, Yao Lu, Dandan Ma, Donghui Shi, Yixun Sun, Mingyu Yang, Jing Li, Junfa Wei
A "Janus" type of hexa- cata-hexabenzocoronene with three triptyceno subunits fused symmetrically on the periphery of coronene has been synthesized using a covalent self-assembly strategy. The triptyceno subunits form a nanosized nest on one side of the aromatic plane with space-matching fullerenes such as C60 and C70 to afford shape-complementary supramolecular complexes. The formation of the complexes in solution was confirmed by1 H NMR and fluorescence titration. Four complexes with C60 or C70 were obtained and studied by single-crystal X-ray diffraction analysis...
April 9, 2018: Organic Letters
https://www.readbyqxmd.com/read/29626894/time-resolved-photoion-imaging-spectroscopy-determining-energy-distribution-in-multiphoton-absorption-experiments
#7
D B Qian, F D Shi, L Chen, S Martin, J Bernard, J Yang, S F Zhang, Z Q Chen, X L Zhu, X Ma
We propose an approach to determine the excitation energy distribution due to multiphoton absorption in the case of excited systems following decays to produce different ion species. This approach is based on the measurement of the time-resolved photoion position spectrum by using velocity map imaging spectrometry and an unfocused laser beam with a low fluence and homogeneous profile. Such a measurement allows us to identify the species and the origin of each ion detected and to depict the energy distribution using a pure Poisson's equation involving only one variable which is proportional to the absolute photon absorption cross section...
April 7, 2018: Journal of Chemical Physics
https://www.readbyqxmd.com/read/29623963/simple-bond-patterns-predict-the-stability-of-diels-alder-adducts-of-empty-fullerenes
#8
Paula Pla, Yang Wang, Manuel Alcamí
We present an extensive and systematic study on the regioselectivity of Diels-Alder (DA) cycloadditions to empty fullerenes, covering the whole range of cage sizes from C60 to C180. Reaction energies obtained from DFT calculations, which correlate with activation barriers, can be well reproduced by using a simple Hückel model, indicating that π electronic effect is the key factor determining the relative stability of DA adducts. Based on these results, we propose a couple of simple rules of thumb, in terms of a set of bond patterns, as a visual guide for approximate prediction of DA reactive sites...
April 6, 2018: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/29619187/hexathioalkyl-sumanenes-an-electron-donating-buckybowl-as-a-building-block-for-supramolecular-materials
#9
Yoshiaki Shoji, Takashi Kajitani, Fumitaka Ishiwari, Qiang Ding, Hiroyasu Sato, Hayato Anetai, Tomoyuki Akutagawa, Hidehiro Sakurai, Takanori Fukushima
Unlike planar aromatic compounds, bowl-shaped sumanene, which has concave and convex faces with different electrostatic potentials, tends to form a one-dimensional columnar assembly without causing slip-stacking in the crystal. Here we report the first successful synthesis of liquid-crystalline (LC) sumanenes, which was brought about by the incorporation of six thioalkyl groups (R = SC6 H13 or SC12 H25 ) into the aromatic part of sumanene. In contrast to the case of the mesophase formation of corannulene, which requires the presence of many dendritic side chains, sumanene derivatives with simple alkyl chains can exhibit a remarkably high-order columnar LC mesophase over a wide temperature range...
December 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/29615794/effect-of-magnetic-fullerene-on-magnetization-reversal-created-at-the-fe-c-60-interface
#10
Srijani Mallik, Stefan Mattauch, Manas Kumar Dalai, Thomas Brückel, Subhankar Bedanta
Probing the hybridized magnetic interface between organic semiconductor (OSC) and ferromagnetic (FM) layers has drawn significant attention in recent years because of their potential in spintronic applications. Recent studies demonstrate various aspects of organic spintronics such as magnetoresistance, induced interface moment etc. However, not much work has been performed to investigate the implications of such OSC/FM interfaces on the magnetization reversal and domain structure which are the utmost requirements for any applications...
April 3, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29603561/two-dimensional-fullerene-assembly-from-an-exfoliated-van-der-waals-template
#11
Kihong Lee, Bonnie Choi, Ilan Jen-La Plante, Maria Paley, Xinjue Zhong, Andrew Crowther, Jonathan Owen, Xiaoyang Zhu, Xavier Roy
Two-dimensional (2D) materials are commonly prepared by exfoliating bulk layered van der Waals crystals. The creation of "synthetic" 2D materials from bottom-up methods represents an important challenge as their structural flexibility will enable chemists to tune the materials' properties. Here we describe a new 2D material assembled using C60 as a polymerizable monomer. The C60 building blocks are first assembled into a layered solid using a molecular cluster as structure director. The resulting hierarchical crystal is used as a template to polymerize its C60 monolayers, which can be exfoliated down to 2D crystalline nanosheets...
March 30, 2018: Angewandte Chemie
https://www.readbyqxmd.com/read/29594543/switched-voltammetric-determination-of-ractopamine-by-using-a-temperature-responsive-sensing-film
#12
Chao Chen, Mingxuan Zhang, Chunyan Li, Yixi Xie, Junjie Fei
This study describes an electrochemical sensor for the animal growth promoter ractopamine. The method is based on the use of a glassy carbon electrode (GCE) modified with a temperature-responsive sensing film composed of reduced graphene oxide, C60 fullerene, and the temperature-sensitive polymer poly(2-(2-methoxyethoxy)ethyl methacrylate) (PMEO2 MA). The modified GCE was characterized by scanning electron microscopy and electrochemical impedance spectroscopy. A large oxidation peak current can be observed (maximum typically at 0...
February 3, 2018: Mikrochimica Acta
https://www.readbyqxmd.com/read/29573077/electronic-communication-between-two-10-cycloparaphenylenes-and-bisazafullerene-c59n-2-induced-by-cooperative-complexation
#13
Jérémy Rio, Sebastian Beeck, Georgios Rotas, Sebastian Ahles, Denis Jacquemin, Nikos Tagmatarchis, Chris Ewels, Hermann Andreas Wegner
The complex of [10]cycloparaphenylene ([10]CPP) with bisazafullerene (C59N)2 is investigated experimentally and computationally. Two [10]CPP rings are bound to the dimeric azafullerene giving [10]CPP⊃(C59N)2⊂[10]CPP. Photophysical and redox properties support an electronic interaction between the com-ponents especially with the second [10]CPP bound. Unlike [10]CPP⊃C60, where there is negligible electronic communication bet¬ween the two species, upon photoexcitation a partial charge trans¬fer phenomenon is revealed between [10]CPP and (C59N)2 reminiscent of CPP encapsulated metallofullerenes...
March 23, 2018: Angewandte Chemie
https://www.readbyqxmd.com/read/29569924/femtosecond-dynamics-of-photoexcited-c-60-films
#14
Martina Causa', Ivan R Ramirez, Josue F Martinez Hardigree, Moritz Riede, Natalie Banerji
The well-known organic semiconductor C60 is attracting renewed attention due to its centimetre-long electron diffusion length and the high performance of solar cells containing 95% fullerene. Yet, its photophysical properties remain poorly understood. Here, we elucidate the dynamics of Frenkel and intermolecular (inter-C60 ) charge transfer (CT) excitons in neat and diluted C60 films from high quality femtosecond transient absorption (TA) measurements, performed at low fluences and free from oxygen or pump-induced photo-dimerization...
March 23, 2018: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/29566528/fullerene-layered-antiferromagnetic-reconstructed-spinterface-subsurface-layer-dominates-molecular-orbitals-spin-split-and-large-induced-magnetic-moment
#15
Yangfan Shao, Rui Pang, Hui Pan, Xingqiang Shi
The interfaces between organic molecules and magnetic metals have gained increasing interest for both fundamental reasons and applications. Among them, the C60 /layered antiferromagnetic (AFM) interfaces have been studied only for C60 bonded to the outermost ferromagnetic layer [S. L. Kawahara et al., Nano Lett. 12, 4558 (2012) and D. Li et al., Phys. Rev. B 93, 085425 (2016)]. Here, via density functional theory calculations combined with evidence from the literature, we demonstrate that C60 adsorption can reconstruct the layered-AFM Cr(001) surface at elevated annealing temperatures so that C60 bonds to both the outermost and the subsurface Cr layers in opposite spin directions...
March 21, 2018: Journal of Chemical Physics
https://www.readbyqxmd.com/read/29561616/can-the-dielectric-constant-of-fullerene-derivatives-be-enhanced-by-side-chain-manipulation-a-predictive-first-principles-computational-study
#16
Selim Sami, Pi A B Haase, Riccardo Alessandri, Ria Broer, Remco W A Havenith
The low efficiency of organic photovoltaic devices has often been attributed to the strong Coulombic interactions between the electron and hole, impeding the charge separation process. Recently, it has been argued that by increasing the dielectric constant of materials used in OPVs, this strong interaction could be screened. In this work, we report the application of periodic density functional theory together with the coupled perturbed Kohn-Sham method to calculate the electronic contribution to the dielectric constant for fullerene C60 derivatives, a ubiquitous class of molecules in the field of organic photovoltaics...
March 21, 2018: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/29558106/a-multifunctional-bis-adduct-fullerene-for-efficient-printable-mesoscopic-perovskite-solar-cells
#17
Chengbo Tian, Shujing Zhang, Anyi Mei, Yaoguang Rong, Yue Hu, Kai Du, Miao Duan, Yusong Sheng, Pei Jiang, Gengzhao Xu, Hongwei Han
The printable mesoscopic perovskite solar cells (PMPSCs) have exhibited great attracting prospects in the energy conversion field due to their high stability and potential scalability. However, the thick perovskite film in the mesoporous layers challenge the charge transportation and increase grain boundary defects, limiting the performance of the PMPSCs. It is critical not only to improve the electric property of the perovskite film but also to passivate the charge traps to improve the device performance. Herein we synthesized a bis-adduct 2, 5-(Dimethyl ester) C60 fulleropyrrolidine (bis-DMEC60 ) via rational molecular design and incorporated it into the PMPSCs...
March 20, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29534325/lithium-ion-endohedral-fullerene-li-c-60-dopants-in-stable-perovskite-solar-cells-induce-instant-doping-and-anti-oxidation
#18
Il Jeon, Hiroshi Ueno, Seungju Seo, Kerttu Aitola, Ryosuke Nishikubo, Akinori Saeki, Hiroshi Okada, Gerrit Boschloo, Shigeo Maruyama, Yutaka Matsuo
Herein, we report use of [Li+ @C60 ]TFSI- as a dopant for spiro-MeOTAD in lead halide perovskite solar cells. This approach gave an air stability nearly 10-fold that of conventional devices using Li+ TFSI- . Such high stability is attributed to the hydrophobic nature of [Li+ @C60 ]TFSI- repelling moisture and absorbing intruding oxygen, thereby protecting the perovskite device from degradation. Furthermore, [Li+ @C60 ]TFSI- could oxidize spiro-MeOTAD without the need for oxygen. The encapsulated devices exhibited outstanding air stability for more than 1000 h while illuminated under ambient conditions...
March 13, 2018: Angewandte Chemie
https://www.readbyqxmd.com/read/29533652/orthogonally-protected-diaminoterephthalate-scaffolds-installation-of-two-functional-units-at-the-chromophore
#19
Leon Buschbeck, Jens Christoffers
The 2,5-diaminoterephthalate structural motif is a powerful chromophore with remarkable fluorescence properties. Containing two carboxylate and two amino functions it defines a colored molecular scaffold which allows for orthogonal functionalization with different functional units. Therefore, different applications in Life Sciences and Materials Science could be addressed. In this study, the two amino functions were alkylated by reductive amination with side chains carrying amino (orthogonally protected as Boc or Alloc) and carboxylate functions (orthogonally protected as tBu or allyl ester)...
March 13, 2018: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/29529565/predictive-modeling-solubility-of-c-60-and-c-70-fullerenes-in-diverse-solvents
#20
Shikha Gupta, Nikita Basant
Solubility of fullerenes imposes a major limitation to further advanced research and technological development using these novel materials. There have been continued efforts to discover better solvents and their properties that influence the solubility of fullerenes. Here, we have developed QSPR (quantitative structure-property relationship) models based on structural features of diverse solvents and large experimental data for predicting the solubility of C60 and C70 fullerenes. The developed models identified most relevant features of the solvents that encode the polarizability, polarity and lipophilicity properties which largely influence the solubilizing potential of the solvent for the fullerenes...
March 1, 2018: Chemosphere
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