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1.
Molecules ; 25(16)2020 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-32784953

RESUMO

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.

2.
Inorg Chem ; 2020 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-32551612

RESUMO

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 C2-unit has been stabilized by three different fullerene cages to form Ti2C2@D3h(5)-C78, Ti2C2@C3v(8)-C82, and Ti2C2@Cs(6)-C82, representing the first examples of unsupported titanium carbide clusters. Crystallographic results show that the configuration of the Ti2C2 cluster changes upon cage variation. In detail, the Ti2C2 cluster adopts a butterfly shape in Ti2C2@C3v(8)-C82 and Ti2C2@Cs(6)-C82 with Ti-C2-Ti dihedral angles of 156.35 and 147.52° and Ti-Ti distances of 3.633 and 3.860 Å, respectively. In sharp contrast, a stretched planar geometry of Ti2C2 is observed in Ti2C2@D3h(5)-C78, where a Ti-C2-Ti angle of 176.87° and a long Ti-Ti distance of 5.000 Å are presented. Consistently, theoretical calculations reveal that the cluster configuration is very sensitive to the cage shape which eventually determines the electronic structures of the hybrid EMF-molecules, thus adding new insights into modern coordination chemistry.

3.
Inorg Chem ; 59(3): 1940-1946, 2020 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-31961666

RESUMO

Six dierbium carbide endohedral metallofullerenes have been synthesized and chromatographically isolated. Single-crystal X-ray diffractometry unambiguously ascertains their structures as Er2C2@C2v(5)-C80, Er2C2@Cs(6)-C82, Er2C2@Cs(15)-C84, Er2C2@C2v(9)-C86, Er2C2@Cs(15)-C86, and Er2C2@Cs(32)-C88, respectively. The Er···Er distances of the major erbium sites inside the Cs(6)-C82, C2v(5)-C80, Cs(15)-C84, Cs(15)-C86, C2v(9)-C86, and Cs(32)-C88 cages are 3.801, 3.860, 4.062, 4.066, 4.307, and 4.372 Å, respectively, which show a linear tendency with an increase in the major axis of the fullerene cages (8.064, 8.238, 8.508, 8.582, 8.815, and 8.953 Å, respectively). Furthermore, the electrochemical and molecular orbital analyses reveal that the redox chemistry of the Er2C2@C80-88 isomers is associated with the carbon cage, which is different from the situations found for typical dimetallofullerenes, such as Y2@C82, Er2@C82-84, and Lu2@C82,86 isomers, which show metal-dependent oxidation processes, indicating the importance of C2 insertion in carbide cluster metallofullerenes.

4.
Nanoscale ; 11(37): 17319-17326, 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31513222

RESUMO

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 C90 cages, namely, Er2C2@C2(43)-C90, Er2C2@C2(40)-C90, Er2C2@C2(44)-C90, and Er2C2@C1(21)-C90, 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 C2(43)-C90 and C2(44)-C90 are crystallographically identified for the first time. Interestingly, the ErEr distance of the major sites in Er2C2@C2(43)-C90, Er2C2@C2(40)-C90, Er2C2@C2(44)-C90, and Er2C2@C1(21)-C90 is 3.927, 4.058, 4.172, and 4.651 Å, respectively, which increases gradually with an increase in the major axis of the cage. Moreover, the bond length of the inner C2-unit decreases progressively with an increase in the ErEr distance, indicating that the inserted C2-unit can serve as a molecular spring to support the strong metal-cage interactions within cages with the same size but different shapes. Hence, the role of cage shape on the cluster configuration is unveiled safely for the as-obtained Er2C2@C90 isomers.

5.
Nanoscale ; 11(28): 13415-13422, 2019 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-31276150

RESUMO

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.

6.
Chemistry ; 25(49): 11538-11544, 2019 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-31290169

RESUMO

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.

7.
Chem Commun (Camb) ; 55(43): 6018-6021, 2019 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-31062003

RESUMO

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.

8.
Chem Sci ; 10(3): 829-836, 2019 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-30774877

RESUMO

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@T d(2)-C76, Lu2@D 3h(5)-C78, Lu2@C 2v(5)-C80, Lu2@C 2v(7)-C84, Lu2@C s(8)-C86, Lu2@C s(15)-C86, Lu2@C 1(26)-C88, Lu2C2@C 2v(9)-C86, Lu2C2@C s(32)-C88 and Lu2C2@D 2(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.

9.
Inorg Chem ; 58(3): 2177-2182, 2019 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-30657317

RESUMO

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-.

10.
Angew Chem Int Ed Engl ; 57(41): 13394-13405, 2018 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-29665229

RESUMO

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. However, many other unidentified fullerene species, which must be reactive and insoluble in their pristine forms, remain in soot. These "missing" species must have extremely small HOMO-LUMO gaps and may have unconventional cage structures. Recent progress in this field has demonstrated that reactive fullerenes can be salvaged by exohedral derivatization, which can stabilize the reactive carbon cages. This concept provides a means of preparing macroscopic amounts of unconventional fullerenes as their derivatives.

11.
ACS Nano ; 12(2): 2065-2069, 2018 02 27.
Artigo em Inglês | MEDLINE | ID: mdl-29400943

RESUMO

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.

12.
Molecules ; 22(7)2017 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-28708116

RESUMO

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. Several examples emphasize that exohedral functionalization regulates the dynamic behaviors of the encapsulated metal atoms and clusters in the fullerene cages. The electronic effects of silyl and germyl groups are represented by comparing the redox properties of silylated and germylated EMFs with those of other EMFs derivatized with carbon-atom-based functional groups.


Assuntos
Carbono/química , Fulerenos/química , Germânio/química , Metais/química , Silício/química , Cinética , Nanopartículas Metálicas/química , Estrutura Molecular , Oxirredução , Relação Estrutura-Atividade
13.
Molecules ; 22(7)2017 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-28672819

RESUMO

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. It is shown that the two non-IPR isomers with one pentagon-pentagon junction prevail at any relevant temperature and exhibit comparable populations. The IPR-satisfying structure is disfavored by both energy and entropy.


Assuntos
Fulerenos/química , Isomerismo , Modelos Moleculares , Temperatura
14.
PLoS One ; 12(6): e0177170, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28594865

RESUMO

BACKGROUND: Traditional and non-traditional risk factors for atherosclerotic cardiovascular disease (ASCVD) are different between men and women. Gender-linked impact of epicardial adipose tissue volume (EATV) in patients undergoing coronary artery bypass grafting (CABG) remains unknown. METHODS: Gender-linked impact of EATV, abdominal fat distribution and other traditional ASCVD risk factors were compared in 172 patients (men: 115; women: 57) who underwent CABG or non-coronary valvular surgery (non-CABG). RESULTS: In men, EATV, EATV index (EATV/body surface area) and the markers of adiposity such as body mass index, waist circumference and visceral fat area were higher in the CABG group than in the non-CABG group. Traditional ASCVD risk factors were also prevalent in the CABG group. In women, EATV and EATV index were higher in the CABG group, but other adiposity markers were comparable between CABG and non-CABG groups. Multivariate logistic regression analysis showed that in men, CABG was determined by EATV Index and other ASCVD risk factors including hypertension, dyslipidemia, adiponectin, high sensitive C-reactive protein (hsCRP) and type 2 diabetes mellitus (Corrected R2 = 0.262, p < 0.0001), while in women, type 2 diabetes mellitus is a single strong predictor for CABG, excluding EATV Index (Corrected R2 = 0.266, p = 0.005). CONCLUSIONS: Our study found that multiple risk factors, including epicardial adipose tissue volume and traditional ASCVD factors are determinants for CABG in men, but type 2 diabetes mellitus was the sole determinant in women. Gender-specific disparities in risk factors of CABG prompt us to evaluate new diagnostic and treatment strategies and to seek underlying mechanisms.


Assuntos
Tecido Adiposo/patologia , Ponte de Artéria Coronária , Valvas Cardíacas/cirurgia , Pericárdio/patologia , Caracteres Sexuais , Idoso , Feminino , Humanos , Masculino , Análise Multivariada , Tamanho do Órgão , Análise de Regressão
16.
Molecules ; 22(5)2017 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-28531116

RESUMO

Photochemical carbosilylation of Lu3N@Ih-C80 was performed using siliranes (silacyclopropanes) to afford the corresponding [5,6]- and [6,6]-adducts. Electrochemical studies indicated that the redox potentials of the carbosilylated derivatives were shifted cathodically in comparison with those of the [5,6]-pyrrolidino adducts. The electronic effect of the silirane addends on Lu3N@Ih-C80 was verified on the basis of density functional theory calculations.


Assuntos
Ciclopropanos/química , Elétrons , Fulerenos/química , Silanos/química , Técnicas Eletroquímicas , Luz , Estrutura Molecular , Oxirredução , Processos Fotoquímicos , Pirrolidinas/química
17.
Angew Chem Int Ed Engl ; 56(23): 6488-6491, 2017 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-28464385

RESUMO

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".

18.
PLoS Genet ; 13(5): e1006786, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28542428

RESUMO

Understanding the cellular-molecular substrates of heart disease is key to the development of cardiac specific therapies and to the prevention of off-target effects by non-cardiac targeted drugs. One of the primary targets for therapeutic intervention has been the human ether a go-go (hERG) K+ channel that, together with the KCNQ channel, controls the rate and efficiency of repolarization in human myocardial cells. Neither of these channels plays a major role in adult mouse heart function; however, we show here that the hERG homolog seizure (sei), along with KCNQ, both contribute significantly to adult heart function as they do in humans. In Drosophila, mutations in or cardiac knockdown of sei channels cause arrhythmias that become progressively more severe with age. Intracellular recordings of semi-intact heart preparations revealed that these perturbations also cause electrical remodeling that is reminiscent of the early afterdepolarizations seen in human myocardial cells defective in these channels. In contrast to KCNQ, however, mutations in sei also cause extensive structural remodeling of the myofibrillar organization, which suggests that hERG channel function has a novel link to sarcomeric and myofibrillar integrity. We conclude that deficiency of ion channels with similar electrical functions in cardiomyocytes can lead to different types or extents of electrical and/or structural remodeling impacting cardiac output.


Assuntos
Arritmias Cardíacas/genética , Proteínas de Drosophila/genética , Drosophila/genética , Canais de Potássio KCNQ/genética , Mutação , Miócitos Cardíacos/fisiologia , Potenciais de Ação , Animais , Drosophila/crescimento & desenvolvimento , Drosophila/fisiologia , Proteínas de Drosophila/metabolismo , Canais de Potássio KCNQ/metabolismo , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia
19.
Chem Asian J ; 12(12): 1391-1399, 2017 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-28452140

RESUMO

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.

20.
JACC Cardiovasc Interv ; 10(3): 235-243, 2017 02 13.
Artigo em Inglês | MEDLINE | ID: mdl-28183464

RESUMO

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 <7 F (odds ratio [OR]: 5.50; p = 0.008), calcification (OR: 3.20; p = 0.001), occlusion length >20 mm (OR: 2.97; p < 0.001), and age (OR: 1.04; p = 0.03) were associated with transradial CTO PCI failure. 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.


Assuntos
Cateterismo Periférico/métodos , Oclusão Coronária/terapia , Intervenção Coronária Percutânea/métodos , Artéria Radial , Idoso , Cateteres Cardíacos , Cateterismo Periférico/efeitos adversos , Cateterismo Periférico/instrumentação , Distribuição de Qui-Quadrado , Doença Crônica , Angiografia Coronária , Oclusão Coronária/diagnóstico por imagem , Desenho de Equipamento , Estudos de Viabilidade , Feminino , Artéria Femoral/diagnóstico por imagem , Humanos , Japão , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Razão de Chances , Seleção de Pacientes , Intervenção Coronária Percutânea/efeitos adversos , Intervenção Coronária Percutânea/instrumentação , Pontuação de Propensão , Artéria Radial/diagnóstico por imagem , Sistema de Registros , Medição de Risco , Fatores de Risco , Resultado do Tratamento
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