Positional Control of Encapsulated Atoms Inside a Fullerene Cage by Exohedral Addition

Yamada, Michio; Nakahodo, Tsukasa; Wakahara, Takatsugu; Tsuchiya, Takahiro; Maeda, Yutaka; Akasaka, Takeshi; Kako, Masahiro; Yoza, Kenji; Horn, Ernst; Mizorogi, Naomi; Kobayashi, Kaoru; Nagase, Shigeru

doi:10.1021/ja054346r

Cited by 115 publications

(114 citation statements)

References 9 publications

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“…This is equaled only in the special case of cerium confined in an endohedral fullerene with a Ce À C distance of 2.436 (6) . [16] Indeed, the Ce=C bond distance in 5 is shorter than all the other cerium-carbon bond distances in this study (Ce À C: 2.539(2)-2.810(2) ), is about 0.3 shorter than dative cerium(IV)-N-heterocyclic carbene distances, [11] and shorter than Ce III ÀC alkyl distances, which average 2.6 . [17] In [18] but here the carbene is planar whereas in 5 the carbene is pyramidalized (Sff = 322.7 (3)8), which accounts for the only marginally shorter Ce = C distance in 5.…”

mentioning

confidence: 69%

A Cerium(IV)–Carbon Multiple Bond

Gregson

McMaster

et al. 2013

Angew Chem Int Ed

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Straightforward access to a cerium(IV)-carbene complex was provided by one-electron oxidation of an anionic "ate" cerium(III)-carbene precursor, thereby avoiding decomposition reactions that plague oxidations of neutral cerium(III) compounds. The cerium(IV)-carbene complex is the first lanthanide(IV)-element multiple bond and involves a twofold bonding interaction of two electron pairs between cerium and carbon.

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confidence: 69%

A Cerium(IV)–Carbon Multiple Bond

Gregson

McMaster

et al. 2013

Angew Chem Int Ed

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“…Disilirane additions were used to control the motion of the encapsulated Ce atoms inside the C 80 cage of Ce 2 @C 80 . In this compound, the free random motion of two Ce atoms is regulated under a hexagonal ring on the equator by the electron donation from the silyl groups, exohedrically introduced, to the C 80 cage [211]. The motion of La atoms encapsulated inside fullerenes has also been controlled exohedrically, by the addition positions, in pyrrolidine adducts of La 2 @C 80 .…”

Section: Chemical Reactivity Of Endohedral Fullerenesmentioning

confidence: 99%

Buckyballs

Delgado

Filippone

Giacalone

et al. 2013

Topics in Current Chemistry

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Buckyballs represent a new and fascinating molecular allotropic form of carbon that has received a lot of attention by the chemical community during the last two decades. The unabating interest on this singular family of highly strained carbon spheres has allowed the establishing of the fundamental chemical reactivity of these carbon cages and, therefore, a huge variety of fullerene derivatives involving [60] and [70]fullerenes, higher fullerenes, and endohedral fullerenes have been prepared. Much less is known, however, of the chemistry of the uncommon non-IPR fullerenes which currently represent a scientific curiosity and which could pave the way to a range of new fullerenes. In this review on buckyballs we have mainly focused on the most recent and novel covalent chemistry of fullerenes involving metal catalysis and asymmetric synthesis, as well as on some of the most significant advances in supramolecular chemistry, namely H-bonded fullerene assemblies and the search for efficient concave receptors for the convex surface of fullerenes. Furthermore, we have also described the recent advances in the macromolecular chemistry of fullerenes, that is, those polymer molecules endowed with fullerenes which have been classified according to their chemical structures. This review is completed with the study of endohedral fullerenes, a new family of fullerenes in which the carbon cage of the fullerene contains a metal, molecule, or metal complex in the inner cavity. The presence of these species affords new fullerenes with completely different properties and chemical reactivity, thus opening a new avenue in which a more precise control of the photophysical and redox properties of fullerenes is possible. The use of fullerenes for organic electronics, namely in photovoltaic applications and molecular wires, complements the study and highlights the interest in these carbon allotropes for realistic practical applications. We have pointed out the so-called non-IPR fullerenes - those that do not follow the isolated pentagon rule - as the most intriguing class of fullerenes which, up to now, have only shown the tip of the huge iceberg behind the examples reported in the literature. The number of possible non-IPR carbon cages is almost infinite and the near future will show us whether they will become a reality.

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“…The presence of only two signals with a 3:1 intensity ratio in the 13 C NMR spectrum shows that the 3D random circulation of the two Ce atoms reduces the symmetry of the molecule to be icosahedral [28], as in the case of La 2 @I h -C 80 [29]. The two signals showed very slight temperature dependence compared to those of Ce 2 @D 2 (10611)-C 72 and Ce 2 @D 3h (5)-C 78 , despite the fact that two Ce atoms are contained in them.…”

Section: Molecular Structure Of Ce 2 @I H -C 80mentioning

confidence: 99%

“…Bis-silylated adduct Thermal reaction of Ce 2 @I h -C 80 with 1,1,2,2-tetramesityl-1,2-disilirane took place smoothly to afford a single isomer of the bis-silylated adduct, Ce 2 @I h -C 80 (Mes 2 Si) 2 CH 2 , in which the two silicon atoms of the substituent are attached on the 1,4-position of the I h -C 80 cage [28]. Results of the X-ray crystallographic analyses showed that the two Ce atoms are localized at two positions directing the hexagonal ring at the equator.…”

Section: Molecular Structure Of Ce 2 @I H -C 80mentioning

confidence: 99%

In-depth understanding of π-electron systems: New vistas in fullerene endohedrals

Yamada

Tsuchiya

Akasaka

et al. 2010

Pure and Applied Chemistry

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The synthesis and characterization of various endohedral metallofullerenes and their derivatives are described. The encapsulated metal atoms' positions and movements were determined using NMR study, X-ray crystallographic analysis, and theoretical calculations. The results of electrochemical investigations clarified the relation between the electronic properties and the π-electron systems of the fullerene endohedrals.the positions and movements of untouchable metal atoms inside spherical π-spaces, along with some insights into their electronic properties. EXPERIMENTALEndohedral metallofullerenes are synthesized in a modified Krätschmer-Huffman generator. A composite rod containing graphite and metal oxide was subjected to an arc discharge as an anode. After annealing, the rod was vaporized in a helium atmosphere by arc discharge. We optimized the arc-discharge conditions (arc current = 256 A, arc voltage = 35 V, and He pressure = 150 Torr) to improve the yields. Carbonaceous soot containing empty fullerenes and endohedral metallofullerenes was obtained. From among the components, soluble fullerene species were extracted from the soot by refluxing in an organic solvent such as N,N-dimethylformamide (DMF). Then the extracts were subjected to high-performance liquid chromatography (HPLC) to isolate endohedral metallofullerenes. RESULTS AND DISCUSSION Molecular structure of Ce@C 2v -C 82It is noteworthy that c pc includes geometrical information (r and θ) related to the encapsulated Ce atoms. We conducted variable-temperature (VT) 13 C NMR measurements of Ce@C 2v -C 82 anion to obtain the experimental c pc values. Use of the least-squares method revealed the distance between Ce and the center of the hexagonal ring along the C 2 axis to be 2.1-2.8 Å. This metal position corresponds to M. YAMADA et al.

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Positional Control of Encapsulated Atoms Inside a Fullerene Cage by Exohedral Addition

Cited by 115 publications

References 9 publications

A Cerium(IV)–Carbon Multiple Bond

A Cerium(IV)–Carbon Multiple Bond

Buckyballs

In-depth understanding of π-electron systems: New vistas in fullerene endohedrals

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