Two-fold addition reaction of silylene to C: structural and electronic properties of a bis-adduct.

The addition reaction of C with silylene , a silicon analog of carbene, yielded the corresponding bis-adduct . The structure of was determined by single-crystal X-ray structure analysis, representing the first example of a crystal structure of a silirane (silacyclopropane) derivative of fullerenes. Electrochemical measurements confirmed that the redox potentials of are shifted cathodically compared to those of the parent mono-adduct .

Element effects in endohedral metal-metal-bonding fullerenes M2@C82 (M = Sc, Y, La, Lu).

Endohedral metal-metal-bonding fullerenes have recently emerged, in which encapsulated metals form a metal-metal bond. However, the physical reasons why some metal elements prefer to form metal-metal bonds inside fullerene are still unclear. Herein, we reported first-principles calculations on electronic structures, bonding properties, dynamics, and thermodynamic stabilities of endohedral metallofullerenes M2@C82 (M = Sc, Y, La, Lu).

Controlling the reactivity of La@C by reduction: reaction of the La@C anion with alkyl halide with high regioselectivity.

Endohedral metallofullerenes have excellent redox properties, which can be used to vary their reactivity to certain classes of molecules, such as alkyl halides. In this study, the thermal reaction of the La@-C anion with benzyl bromide derivatives at 110 °C afforded single-bonded adducts - with high regioselectivity. The products were characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and visible-near infrared spectroscopy.

Fullerene-Derived Porous and Defective N-Doped Carbon Nanosheets as Advanced Trifunctional Metal-Free Electrocatalysts.

Dopants and defects are crucial for multifunctional carbon-based metal-free electrocatalysts, but the rational design and facile production remain as a big challenge. Herein, we report a novel strategy using salt-assisted pyrolysis of derivatized fullerenes to fabricate defect-rich and N-doped carbon nanosheets. Molecular level modification of C via amination and hydroxylation gives rise to well-defined fullerol molecules bearing N-containing groups (FNG).

Cluster-Geometry-Associated Metal-Metal Bonding in Trimetallic Carbide Clusterfullerenes.

Geometry configurations of the metallic clusters play a significant role in the involved bonding nature. Herein, we report the crystallographic characterization of unprecedented erbium-based trimetallic clusterfullerenes, namely, ErC@(7)-C, in which the inner ErC cluster presents a lifted bat ray configuration with the C unit elevated by ∼1.62 Å above the Er plane.

Defective porous carbon microrods derived from fullerenes (C) as high-performance electrocatalysts for the oxygen reduction reaction.

Disrupting the integrity of the sp-carbon skeleton offers an effective strategy to create active sites for the oxygen reduction reaction (ORR). In this work, fullerene (C) molecules, composed of 12 pentagons and 25 hexagons all bonded by sp-C atoms, are assembled into microrods (C70MRs) at the liquid-liquid interface and then broken down by calcination to generate metal-free fullerene-derived ORR electrocatalysts. The effect of the pyrolysis temperature on C70MRs is investigated, and it is found that pyrolysis at 900 °C effectively unfolds the C cages and converts them into a highly porous, defect-rich carbon material (C70MRs-900) with the rod-shaped morphology well-retained.

Correction: Unexpected formation of 1,2- and 1,4-bismethoxyl ScN@ -C derivatives regioselective anion addition: an unambiguous structural identification and mechanism study.

[This corrects the article DOI: 10.1039/D1SC01178B.].

Unexpected formation of 1,2- and 1,4-bismethoxyl ScN@ -C derivatives regioselective anion addition: an unambiguous structural identification and mechanism study.

An attempt to achieve heterocyclic cycloadducts of ScN@ -C reaction with PhC[double bond, length as m-dash]O, PhC[triple bond, length as m-dash]CPh or PhC[triple bond, length as m-dash]N in the presence of tetrabutylammonium hydroxide (TBAOH) stored in CHOH led to the formation of the unexpected bismethoxyl adducts of ScN@ -C ( and ). Further studies reveal that TBAOH in CHOH can boost the CHO addition efficiently, regardless of the presence of other reagents. Single-crystal X-ray diffraction results firmly assign the molecular structures of and as respective 1,4- and 1,2-bismethoxyl adducts, and reveal unusual relationships between the internal ScN cluster and the addition modes, in addition to the unusual packing mode in view of the orientation of the methoxyl groups.

Morphology Engineering of Fullerene[C ] Microcrystals: From Perfect Cubes, Defective Hoppers to Novel Cruciform-Pillars.

Controlled crystallization of fullerene molecules into ordered molecular assemblies is important for their applications. However, the morphology engineering of fullerene[C ] assemblies is challenging, and complicated architectures have rarely been reported due to the low molecular symmetry of C 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 C microcrystals with mesitylene as a good solvent and n-propanol as a poor solvent in one solvent system without replacing specific solvents.

Metal-encapsulation induces a highly regioselective Bingel-Hirsch reaction of the labile Y@(6)-C.

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.

New Horizons in Chemical Functionalization of Endohedral Metallofullerenes.

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.

Crystallographic Characterization of TiC@(5)-C, TiC@(8)-C, and TiC@(6)-C: Identification of Unsupported TiC Cluster with Cage-Dependent Configurations.

Fullerene cages are ideal hosts to encapsulate otherwise unstable metallic clusters to form endohedral metallofullerenes (EMFs). Herein, a novel TiC cluster with two titanium atoms bridged by a C-unit has been stabilized by three different fullerene cages to form TiC@(5)-C, TiC@(8)-C, and TiC@(6)-C, representing the first examples of unsupported titanium carbide clusters. Crystallographic results show that the configuration of the TiC cluster changes upon cage variation.

Overexpression of in the Developing Heart Causes Valvar and Contractility Defects: Implications for Human Congenital Heart Disease.

Left-sided congenital heart defects (CHDs) are among the most common forms of congenital heart disease, but a disease-causing gene has only been identified in a minority of cases. Here, we identified a candidate gene for CHDs, , that was associated with a chromosomal balanced translocation t(2;8)(q37;p11) in a patient with left-sided heart and aortic valve defects. The breakpoint was in the 5' untranslated region of the gene at 2q37, which suggested that the break affected the levels of gene expression.

Crystallographic Characterization of ErC@C: Cluster Stretching with Cage Elongation.

Six dierbium carbide endohedral metallofullerenes have been synthesized and chromatographically isolated. Single-crystal X-ray diffractometry unambiguously ascertains their structures as ErC@(5)-C, ErC@(6)-C, ErC@(15)-C, ErC@(9)-C, ErC@(15)-C, and ErC@(32)-C, respectively. The Er···Er distances of the major erbium sites inside the (6)-C, (5)-C, (15)-C, (15)-C, (9)-C, and (32)-C cages are 3.

Crystallographic characterization of ErC@C(43)-C, ErC@C(40)-C, ErC@C(44)-C, and ErC@C(21)-C: the role of cage-shape on cluster configuration.

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 cages, namely, ErC@C(43)-C, ErC@C(40)-C, ErC@C(44)-C, and ErC@C(21)-C, were successfully synthesized and fully characterized using a combination of mass spectrometry, single-crystal X-ray diffractometry, vis-NIR, Raman and photoluminescence spectroscopies, and cyclic voltammetry. In particular, the fullerene cages of C(43)-C and C(44)-C are crystallographically identified for the first time.

Crystallographic and Theoretical Investigations of Er @C (2 n=82, 84, 86): Indication of Distance-Dependent Metal-Metal Bonding Nature.

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 Er @C (6)-C , Er @C (8)-C , Er @C (12)-C , and Er @C (9)-C , in which the structure of the C (12)-C 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 Er @C (6)-C , Er @C (8)-C , and Er @C (9)-C form a two-electron-two-center Er-Er bond.

Crystallographic characterization of ErN@C (2n = 80, 82, 84, 88): the importance of a planar ErN cluster.

A series of Er-based nitride clusterfullerenes (NCFs), ErN@C, have been successfully synthesized and isolated. In particular, ErN@I(7)-C, ErN@D(6)-C, ErN@C(9)-C, ErN@C(51365)-C, and ErN@D(35)-C have been characterized by single-crystal X-ray diffraction (XRD) for the first time. The planar configuration of the inserted ErN cluster is identified unambiguously and the Er-N distances increase in accordance with cage expansion to maintain strong metal-cage interactions.

Intermolecular packing and charge transfer in metallofullerene/porphyrin cocrystals.

Charge transfer in metallofullerene/porphyrin cocrystals is revealed for the first time. Originated from the different solvents for crystallization, distinct stacking manners are presented in the two types of cocrystals. It is demonstrated that intermolecular packing, next to the nature of the corresponding electron donors and acceptors, dominates the charge transfer processes.

Crystallographic characterization of LuC (2 = 76-90): cluster selection by cage size.

The successful isolation and unambiguous crystallographic assignment of a series of lutetium-containing endohedral metallofullerenes (EMFs), LuC (2 = 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 Lu@ (2)-C, Lu@ (5)-C, Lu@ (5)-C, Lu@ (7)-C, Lu@ (8)-C, Lu@ (15)-C, Lu@ (26)-C, LuC@ (9)-C, LuC@ (32)-C and LuC@ (35)-C. Specifically, when the cage is relatively small, Lu@C (2 = 76-86) are all dimetallofullerenes (di-EMFs) and a Lu-Lu single bond could be formed between the two lutetium ions inside the cages.

Isolation and Structural Characterization of Er@ C(9)-C and Er@ C (6)-C: Regioselective Dimerization of a Pristine Endohedral Metallofullerene Induced by Cage Symmetry.

Two Er@C isomers have been isolated and unambiguously characterized as Er@ C(9)-C and Er@ C (6)-C, respectively, by single-crystal X-ray diffraction. Er@ C (6)-C is identified as a dimeric structure in the crystalline state, but dimerization does not occur for Er@ C(9)-C 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 (6)-C, which leads to regioselective dimerization.

Salvaging Reactive Fullerenes from Soot by Exohedral Derivatization.

The awesome allotropy of carbon yields innumerable topologically possible cage structures of molecular carbon. This field is also related to endohedral metallofullerenes constructed by metal-atom encapsulation. Stable and soluble empty fullerenes and endohedral metallofullerenes are available in pure form in macroscopic amounts from carbon arc production or other physical processes followed by extraction and subsequent chromatographic separation.

Facile Access to YC (2n = 92-130) and Crystallographic Characterization of YC@C(1660)-C: A Giant Nanocapsule with a Linear Carbide Cluster.

A series of giant metallofullerenes YC (2n = 92-130) have been successfully obtained through the treatment of the fraction enriched by 1,2-dichlorobenzene with SnCl. Subsequent chromatographic separation gives a pure sample with a composition of YC. Crystallographic results reveal that this endohedral takes the carbide form, namely YC@C(1660)-C, representing as the largest metallofullerene that has been characterized by crystallography to date.

Functionalization of Endohedral Metallofullerenes with Reactive Silicon and Germanium Compounds.

Exohedral derivatization of endohedral metallofullerenes (EMFs) has been exploited as a useful method for characterizing the structural and chemical properties of EMFs, and for functionalizing them for potential applications. The introduction of heteroatoms, such as electropositive silicon atoms, to fullerene cages is a novel functionalization method that remarkably affects the electronic characteristics of fullerenes. This review comprehensively describes the results of the reactions of monometallofullerene, dimetallofullerene, and trimetallic nitride template EMFs with disilirane, silirane, silylene, and digermirane, which afforded the corresponding silylated and germylated fullerenes.

Eu@C: Computed Comparable Populations of Two Non-IPR Isomers.

Relative concentrations of six isomeric Eu@C 72 -one based on the IPR C 72 cage (i.e., obeying the isolated-pentagon rule, IPR), two cages with a pentagon-pentagon junction (symmetries C 2 and C 2 v ), a cage with one heptagon, a cage with two heptagons, and a cage with two pentagon-pentagon fusions-are DFT computed using the Gibbs energy in a broad temperature interval.

Synthesis and Photoinduced Electron-Transfer Reactions in a La @I -C -Phenoxazine Conjugate.

A newly designed electron donor-acceptor conjugate consisting of an endohedral dimetallofullerene (La @I -C ) and phenoxazine (POZ) was successfully synthesized under Prato conditions. Our results document that the 1,3-dipolar cycloaddition took place across the [5,6] junction to afford exclusively the corresponding [5,6] cycloadduct. The structure of the conjugate was characterized by means of NMR spectroscopy, absorption spectroscopy, and electrochemical studies.