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Reducing inter-spin distance can enable effective magnetic interactions to realize outstanding magnetic properties, which, however, remains rather challenging. Here, an unprecedented 3d-4f metal cluster (Dy2VN) was constructed inside a C80 cage, affording a heretofore unseen metallofullerene containing both paramagnetic 3d and 4f metal ions. Significantly suppressed 3d-4f (Dy-V) distances, due to the unique cage confinement effect, are directly recorded by crystallographic and theoretical analysis of Dy2VN@Ih(7)-C80. Consequently, superior magnetic coupling (Jtotal, Dy-V = 53.30 cm-1; Jtotal, Dy-Dy = -18.75 cm-1) is obtained, leading to a record-high magnetic blocking temperature among all reported 3d-4f single-molecule magnets and huge coercive field of 2.73 Tesla. Our work puts forth a new class of single-molecule magnets with both paramagnetic 3d and 4f metals confined in a fullerene cage, of which superior and tunable magnetic properties are envisioned thanks to the unique cage confinement effect and the diverse composition of the entrapped magnetic core.

A biliary stent is used to expand the bile duct during interventional treatment of biliary stricture. To reduce the complications after stent implantation, it is necessary to understand and improve the comprehensive performance of magnesium alloy biliary stents. In this study, at first, the mechanical performance of magnesium alloy biliary stent in bile ducts with different ellipticitiesis studied, and the influence of the ellipticity of bile duct on the interaction of the stent-bile duct coupling system is better understood. Proposed results show the increment of ellipticity of the bile duct will increase the difficulty of expanding the stent. Second, to improve the mechanical performance and degradation performance of the stent simultaneously, an optimal design method based on a zero-order algorithm is used to reduce the maximum equivalent stress on the stent effectively, to make the stress distribution more uniform, and to expand the bile duct of the lesion more effectively and uniformly. The results of this analysis and optimization are useful to predict the clinical effect of stents and to design and optimize stents for both bile duct and other non-vascular.

Chemical modification of endohedral metallofullerenes (EMFs) is an efficient strategy to realize their ultimate applications in many fields. Herein, we report the highly regioselective and quantitative mono-formation of pyrazole- and pyrrole-ring-fused derivatives of the prototypical di-EMF Y2 @C3v (8)-C82 , that is, Y2 @C3v (8)-C82 (C13 N2 H10 ) and Y2 @C3v (8)-C82 (C9 NH11 ), from the respective 1,3-dipolar reactions with either diphenylnitrilimine or N-benzylazomethine ylide, without the formation of any bis- or multi-adducts. Crystallographic results unambiguously reveal that only one [6,6]-bond out of the twenty-five different types of nonequivalent C-C bonds of Y2 @C3v (8)-C82 is involved in the 1,3-dipolar reactions. Our theoretical results rationalize that the remarkably high regioselectivity and the quantitative formation of mono-adducts are direct results from the anisotropic distribution of π-electron density on the C3v (8)-C82 cage and the local strain of the cage carbon atoms as well. Interestingly, electrochemical and theoretical studies demonstrate that the reversibility of the redox processes, in particular the reversibility of the reductive processes of Y2 @C3v (8)-C82 , has been markedly altered upon exohedral functionalization, but the oxidative process was less influenced, indicating that the oxidation is mainly influenced by the internal Y2 cluster, whereas the reduction is primarily associated with the fullerene cage. The pyrazole and pyrrole-fused derivatives may find potential applications as organic photovoltaic materials and biological reagents.

Variation of the reaction conditions with Cu powder, Cu(NO3)2, and tBuC≡CH as starting materials afforded three new Cu(I) alkynyl complexes, namely, [Cu14(tBuC≡C)10(NO3)4(MeOH)2]·H2O (1), Cu15(tBuC...

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...

Interactions between the inner and outer units through a fullerene cage are of fundamental importance for the creation of molecular spintronics and machines, but the mechanism of such through-cage interplay is still unclear. In this work, we have designed and synthesized two prototypical compounds which contain only a single europium atom inside the cage and merely a tungsten atom coordinating outside to clarify the interactions between the endohedral and exohedral metallic units. They are obtained by reacting a tungsten complex W(CO)4(Ph2PC2H4PPh2) (1) with the corresponding metallofullerenes in a highly regioselective manner (2a for Eu@C2(5)-C82 and 2b for Eu@C2(13)-C84). On the one hand, the endohedral Eu-doping has changed the LUMO distribution on C2(5)-C82/C2(13)-C84 dramatically, via electron transfer, which governs the addition pattern of the exohedral tungsten resulting in surprisingly high regioselectivity. On the other hand, the exohedral tungsten coordination with Eu@C2(5)-C82/Eu@C2(13)-C84 has restricted the motion of the internal europium ion to some extent by changing the electrostatic potentials, as confirmed by the X-ray results of 2a, 2b and the corresponding pristine metallofullerenes cocrystallized with Ni(OEP) (OEP is the dianion of octaethylporphyrin). We now make it clear that the interplay between the endohedral and exohedral metallic units can be realized in a single system by means of intramolecular charge transfer, which may arouse interest in the design and utilization of novel metallofullerene-based molecular devices.

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.

Revealing the transformation routes among existing fullerene isomers is key to understanding the formation mechanism of fullerenes which is still unclear now because of the absence of typical key links. Herein, we have crystallographically identified four new fullerene cages, namely, C2(27)-C88, C1(7)-C86, C2(13)-C84 and C2(11)-C84, in the form of Eu@C2n, which are important links to complete a transformation map that contains as many as 98% (176 compounds in total) of the reported metallofullerenes with clear cage structures (C2n, 2n = 86–74). Importantly, the mutual transformations between the metallofullerene isomers included in the map require only one or two well-established steps (Stone–Wales transformation and/or C2 insertion/extrusion). Moreover, structural analysis demonstrates that the unique C2(27)-C88 cage may serve as a key point in the map and is directly transformable from a graphene fragment. Thus, our work provides important insights into the formation mechanism of fullerenes.

Open-cage fullerene derivatives with up to three hydroxyl groups on the rim of an orifice were prepared through modification of functional groups followed by controlled stepwise reduction of carbonyl groups on the rim. The hydroxyl groups form a unidirectional H-bond network and show a weak but clear interaction with a water molecule trapped inside the fullerene cage. Titanium ions coordinated with the hydroxyl and carbonyl groups to form a TiL2 type of complex.

The sub-nanometer cavity of fullerene cages is an ideal platform to accommodate otherwise unstable species for accurate structural characterization with, for example, rather accurate single crystal X-ray diffraction (XRD) crystallography. Herein, we report the successful entrapment of an isolated Ti3C3 moiety inside the icosahedral-C80 cage to form Ti3C3@Ih-C80via an arc-evaporation process in the gas phase. The single crystal XRD crystallographic results unambiguously reveal that the C3-unit adopts an unprecedented cyclopropane-like structure which coordinates with the three titanium atoms in an unexpected fashion where the triangular C3-unit is nearly perpendicular to the Ti3-plane. The intercalation of a cyclopropanated C3-unit into the titanium layer is thus unambiguously confirmed. The theoretical results reveal that the Ti3C3 cluster transfers six electrons to the Ih-C80 cage so that each titanium atom has a positive charge slightly above +2 and the C3-unit is negatively charged with about −1. It is noteworthy that this is the first observation of the cyclopropane-coordination fashion in any reported organometallic complex, providing new insights into coordination chemistry.

An open-cage [60]fullerene was prepared through a multiple-step sequence based on peroxide-mediated cage-opening reactions. Key steps include repeated C60 -sensitized singlet-oxygen oxidation of electron-rich amino enol double bonds to form two lactone and two lactam moieties on the rim of the orifice. Single-crystal X-ray analysis shows that the 22-membered orifice has an ellipsoid shape with the major axis at 6.7 A and the minor axis at 3.5 A. Encapsulation of H2 O2 was observed under atmospheric pressure at room temperature. Oxygen is also effectively trapped during the process.

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.

Novel polyhedral oligomeric silsesquioxanes derivative, N-((4-hydroxyphenyl)-N-(9, 10-dihydro-9-oxa-10-phosphaphenanthene-10-yl) methyl) aminopropyl silsesquioxane (denoted as HDP) was successfully synthesized via the classical Kabachnik-Fields reaction using 3-aminopropyl POSS (POSS-NH2), 4-hydroxybenzaldehyde and 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) as raw materials and well-characterized by FT-IR, 1H, 31P NMR and mass spectroscopy. Herein, particular attention was focused on the solubility between HDP and DGEBA as well as the effect of HDP on flame retardancy of EP. X-ray diffraction (XRD) result showed that HDP owned a low crystallinity and exhibited a good solubility in DGEBA. Thermogravimetry analysis (TGA) in combined with limiting oxygen index (LOI) demonstrated that HDP had the perfect thermal stability and can improved the flame retardancy of EP in some extent (LOI value increase from 25.4% to 28.3%).

Although most of the M2C2n-type metallofullerenes (EMFs) tend to form carbide cluster EMFs, we report herein that Lu-containing EMFs Lu2C2n (2n = 82, 84, 86) are actually dimetallofullerenes (di-EMFs), namely, Lu2@Cs(6)-C82, Lu2@C3v(8)-C82, Lu2@D2d(23)-C84, and Lu2@C2v(9)-C86. Unambiguous X-ray results demonstrate the formation of a Lu–Lu single bond between two lutetium ions which transfers four electrons in total to the fullerene cages, thus resulting in a formal divalent state for each Lu ion. Population analysis indicates that each Lu atom formally donates a 5d electron and a 6s electron to the cage with the remaining 6s electron shared with the other Lu atom to form a Lu–Lu single bond so that only four electrons are transferred to the fullerene cages with the formal divalent valence for each lutetium ion. Accordingly, we confirmed both experimentally and theoretically that the dominating formation of di-EMFs is thermodynamically very favorable for Lu2C2n isomers.

In this work, the magnetic resonance imaging (MRI) radio frequency (RF)-induced heating mechanism for an esophageal stent is discussed from the prospective of forward scattering and the reciprocity theorem. We conclude that the RF-induced heating largely depends on the induced currents on the surface of the stent. Based on this understanding, a novel implantable segmented stent structure is developed to reduce the RF-induced heating of an esophageal stent under MRI procedures. By using a segmented structure, the specific absorption rate (SAR) for a 10-mm-radius and 98-mm-length stent decreased from 53.0 to 14.2 W/kg at a whole-body average SAR of 2 W/kg, and the maximum temperature rise over 15-min MRI exam is reduced from 4.52 to 1.72 $^\circ$ C. The simulated results and experimental measurements agree with each other within the combined uncertainty and demonstrate the effectiveness of the structured stent design. Related to RF-induced heating, this novel design can be used to develop inherently safe esophageal stents.

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.

Chemical modification of endohedral metallofullerenes (EMFs) is an efficient strategy to realize their ultimate applications in many fields. Herein, we report the highly regioselective and quantitative mono-formation of pyrazole- and pyrrole-ring-fused derivatives of the prototypical di-EMF Y

An unexpected cyclopropanated C3-ring coordinating with a Ti3-unit is successfully entrapped inside the icosahedral-C80 cage., The sub-nanometer cavity of fullerene cages is an ideal platform to accommodate otherwise unstable species for accurate structural characterization with, for example, rather accurate single crystal X-ray diffraction (XRD) crystallography. Herein, we report the successful entrapment of an isolated Ti3C3 moiety inside the icosahedral-C80 cage to form Ti3C3@Ih-C80via an arc-evaporation process in the gas phase. The single crystal XRD crystallographic results unambiguously reveal that the C3-unit adopts an unprecedented cyclopropane-like structure which coordinates with the three titanium atoms in an unexpected fashion where the triangular C3-unit is nearly perpendicular to the Ti3-plane. The intercalation of a cyclopropanated C3-unit into the titanium layer is thus unambiguously confirmed. The theoretical results reveal that the Ti3C3 cluster transfers six electrons to the Ih-C80 cage so that each titanium atom has a positive charge slightly above +2 and the C3-unit is negatively charged with about –1. It is noteworthy that this is the first observation of the cyclopropane-coordination fashion in any reported organometallic complex, providing new insights into coordination chemistry.

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.

Although the major isomers of M@C82 (namely M@C2v (9)-C82 , where M is a trivalent rare-earth metal) have been intensively investigated, the lability of the minor isomers has meant that they have been little studied. Herein, the first isolation and crystallographic characterization of the minor Y@C82 isomer, unambiguously assigned as Y@Cs (6)-C82 by cocrystallization with Ni(octaethylporphyrin), is reported. Unexpectedly, a regioselective dimerization is observed in the crystalline state of Y@Cs (6)-C82 . In sharp contrast, no dimerization occurs for the major isomer Y@C2v (9)-C82 under the same conditions, indicating a cage-symmetry-induced dimerization process. Further experimental and theoretical results disclose that the regioselective dimer formation is a consequence of the localization of high spin density on a special cage-carbon atom of Y@Cs (6)-C82 which is caused by the steady displacement of the Y atom inside the Cs (6)-C82 cage.

A transformation map covering as many as 98% of metallofullerenes with clear C2n (2n = 74–86) cage structures is uncovered with C2(27)-C88, C1(7)-C86, C2(13)-C84 and C2(11)-C84 as key links., Revealing the transformation routes among existing fullerene isomers is key to understanding the formation mechanism of fullerenes which is still unclear now because of the absence of typical key links. Herein, we have crystallographically identified four new fullerene cages, namely, C2(27)-C88, C1(7)-C86, C2(13)-C84 and C2(11)-C84, in the form of Eu@C2n, which are important links to complete a transformation map that contains as many as 98% (176 compounds in total) of the reported metallofullerenes with clear cage structures (C2n, 2n = 86–74). Importantly, the mutual transformations between the metallofullerene isomers included in the map require only one or two well-established steps (Stone–Wales transformation and/or C2 insertion/extrusion). Moreover, structural analysis demonstrates that the unique C2(27)-C88 cage may serve as a key point in the map and is directly transformable from a graphene fragment. Thus, our work provides important insights into the formation mechanism of fullerenes.

An open-cage [60]fullerene was prepared through a multiple-step sequence based on peroxide-mediated cage-opening reactions. Key steps include repeated C

The organometallic chemistry of endohedral metallofullerenes has lagged far behind that of empty fullerenes. Herein, we report a highly regioselective coordination reaction involving two Sc3N@C80 isomers and W(CO)4(Ph2PC2H4PPh2) (1), which affords only one mononuclear complex for each Sc3N@C80 isomer (2a for Sc3N@Ih-C80 and 2b for Sc3N@D5h-C80). X-ray results demonstrate that the tungsten center coordinates with the cages in an η(2) fashion on a [6,6]-bond in both cases, forming the first derivatives with a closed three membered ring for Sc3N@C80. Although IR and absorption spectroscopic results reveal relatively weak exohedral-metal to ligand π back-donation in both 2a and 2b, they show remarkable air-stability which promises their potential uses in related fields. Moreover, the coordination has narrowed down the electrochemical gaps of the parent Sc3N@C80 isomers, making the complexes better electron donors but worse electron acceptors than the corresponding precursors.

A series of giant metallofullerenes Y

Although most of the M

In this work, a novel implantable medical stent is designed to reduce the radio frequency (RF)-induced heating from implantable medical stent under magnetic resonance imaging (MRI) procedure. By using segmented structure, the induced specific absorption rate (SAR) for a 100 mm length stent is reduced from 54.4 mW/g to 13.4 mW/g. Numerical simulation demonstrates the effectiveness of the designed structure.

Highly regioselective 1,3-dipolar cycloaddition of 3,5-dichloro-2,4,6-trimethoxybenzonitrile oxide (1) to Sc3N@Ih-C80 or C60 affords the corresponding isoxazoline-ring-fused derivatives Sc3N@Ih-C80(C10H9O4NCl2) (2a) and C60(C10H9O4NCl2) (2b). 2a represents the first example of an endohedral metallofullerene derivative with an isoxazoline ring. Crystallographic and NMR spectroscopic studies reveal a [5,6]-bond addition pattern in 2a but a [6,6]-bond addition manner in 2b.

The organometallic chemistry of endohedral metallofullerenes has lagged far behind that of empty fullerenes. Herein, we report a highly regioselective coordination reaction involving two Sc3N@C80 isomers and W(CO)4(Ph2PC2H4PPh2) (1), which affords only one mononuclear complex for each Sc3N@C80 isomer (2a for Sc3N@Ih-C80 and 2b for Sc3N@D5h-C80). X-ray results demonstrate that the tungsten center coordinates with the cages in an η(2) fashion on a [6,6]-bond in both cases, forming the first derivatives with a closed three membered ring for Sc3N@C80. Although IR and absorption spectroscopic results reveal relatively weak exohedral-metal to ligand π back-donation in both 2a and 2b, they show remarkable air-stability which promises their potential uses in related fields. Moreover, the coordination has narrowed down the electrochemical gaps of the parent Sc3N@C80 isomers, making the complexes better electron donors but worse electron acceptors than the corresponding precursors.

Endohedral metallofullerenes (EMFs) have novel structures and properties that are closely associated with the internal metallic species. Benzyl radical additions have been previously shown to form closed-shell adducts by attaching an odd number of addends to open-shell EMFs (such as Sc3 C2 @Ih -C80 ) whereas an even number of groups are added to closed-shell EMFs (for example Sc3 N@Ih -C80 ). Herein we report that benzyl radical addition to the closed-shell La2 @Ih -C80 forms a stable, open-shell monoadduct instead of the anticipated closed-shell bisadduct. Single-crystal X-ray diffraction results show the formation of a stable radical species. In this species, the La-La distance is comparable to the theoretical value of a La-La covalent bond and is shorter than reported values for other La2 @Ih -C80 derivatives, providing unambiguous evidence for the formation of direct La-La bond.

Carbide cluster metallofullerenes (CCMFs) have drawn more and more attention during recent years due to their special structures and properties1 - 3. Herein, we found that some unprecedented medium-sized carbon cages ranging from C86 to C90 can be stabilized by choosing suitable metal atoms (yttrium). Our single-crystal crystallographic results unambiguously showed that they are carbide cluster metallofullerenes Y2C2@C2n (2n=86,88 and 90). It is proposed that the size of the encapsulated metallic units plays a crucial role in stabilization of these medium-sized fullerene cages. Reference (1) Lu, X.; Akasaka, T.; Nagase, S. Carbide Cluster Metallofullerenes: Structure, Properties, and Possible Origin. Acc. Chem. Res. 2013, 47 (7), 1627–1635. (2) Cai, W.; Bao, L.; Zhao, S.; Xie, Y.; Akasaka, T.; Lu, X. Anomalous Compression of D5(450)-C100 by Encapsulating La2C2 Cluster instead of La2. J. Am. Chem. Soc. 2015, 137 (32), 10292–10296. (3) Cai, W.; Li, F.-F.; Bao, L.; Xie, Y.; Lu, X. Isolation and Crystallographic Characterization of La2C2@Cs(574)-C102 and La2C2@C2(816)-C104: Evidence for the Top-Down Formation Mechanism of Fullerenes. J. Am. Chem. Soc. 2016, 138 (20), 6670–6675.

To identify the specific antigens of the fifth stage larvae (larvae V) of Angiostrongylus cantonensis in soluble proteins.The techniques of two-dimensional electrophoresis (2-DE) and immunoblot were employed to analyze the soluble components of larvae V antigens. The resulting protein spots were identified by mass spectrometry and the specific antigen and immunogenic peptide segment profiles determined.Larvae V was identified by immunoblot of peptide immune murine sera.Immunoblot of 2-DE showed that there were 8 specific antigen spots in females and 4 in males of larvae V. The 12 protein spots had a pH range of 5-7 and a molecular weight of 24-40 kD. Among 12 spot, actin-1 and galectin-1 were identified successfully. And a peptide (NH2-KNGDIALHFNPRFDEK) was predicted as epitope and synthesized. The binding capacity of murine immune sera could identify the 32 000 of larvae V.Galectin and actin are common antigens of female and male larvae V of A.cantonensis. And a peptide from galectin-1 may become a potential target for immunologic diagnosis and immunological mediator.