Synthesis of Endohedral Metallofullerene Glycoconjugates by Carbene Addition

Yamada, Michio; Someya, Chika I.; Nakahodo, Tsukasa; Maeda, Yutaka; Tsuchiya, Takahiro; Akasaka, Takeshi

doi:10.3390/molecules16119495

Cited by 16 publications

(8 citation statements)

References 42 publications

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“…Carbene addition of an appropriate glycosylidene-derived diazirine (12) to La 2 @C 80 at room temperature gave rise to the corresponding La 2 @C 80 -glyco conjugate. 45 Formation of the monoadduct was firmly confirmed by mass spectrometry. As to the molecular structure, NMR and absorption results revealed that two diastereomers of the [6,6]-open adduct exist in the reaction mixture.…”

Section: Carbene Cycloadditionmentioning

confidence: 84%

Recent progress in the chemistry of endohedral metallofullerenes

Bao

Akasaka

et al. 2014

Chem. Commun.

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Putting metal atoms or metallic clusters into fullerenes has generated a new class of hybrid molecules, defined as endohedral metallofullerenes (EMFs), possessing novel structures and fascinating properties which are different from those of empty fullerenes. In particular, it has been revealed that the chemical properties of the cage carbons of EMFs depend strongly on the nature of the internal metallic species, such as their electronic configuration, location and even motion. Since the first report describing the successful derivatization of La@C82 in 1995, great efforts have been devoted to the chemical modification of EMFs during the last two decades. Although earlier studies mainly focused on readily available species such as M@C82, M2@C80 and M3N@C80 and the related results have been systematically summarized in our previous review paper (Chem. Commun., 2011, 47, 5942-5957), recent concerns about some relatively rare EMFs have developed rapidly. Moreover, taking advantage of single crystal X-ray crystallography, we can now clearly demonstrate the mutual influences between the internal metallic species and the chemical behaviours of the surrounding cage carbons, and the addends as well. In this article, we present recent achievements in the chemical functionalization of EMFs, which were mainly published during the last four years. For consistency, we will still pay special attention to the role that the metals play in controlling the properties of the whole EMF molecules. In this review, however, we will not only focus on concrete experimental results such as X-ray crystallographic and NMR spectroscopic data but will also include computational studies which have indeed enhanced our understanding of the chemical properties of EMFs. Applicable materials based on EMFs are also mentioned but are not discussed in detail.

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Section: Carbene Cycloadditionmentioning

confidence: 84%

Recent progress in the chemistry of endohedral metallofullerenes

Bao

Akasaka

et al. 2014

Chem. Commun.

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“…Although most methodologies led to the direct anchorage of one residue, including pioneering investigations by Vasella et al based on glycosylidene carbene precursors, 254,255 thermal cycloadditions, 256,257 and versatile 1,3-dipolar cycloaddition of azomethine ylides (Prato reaction), 258,259 alternative approaches using the initial introduction of suitable chemical functionalities onto the C 60 , have been developed via nitrene trapping, 260 addition-elimination of stabilized sulfonium ylides to generate [60]fullerenoacetyl chloride, 261,262 and [4+2] Diels-Alder reaction (Fig. 24).…”

Section: Monovalent Glycosylated Fullerenesmentioning

confidence: 99%

Multivalent glycoconjugate syntheses and applications using aromatic scaffolds

2013

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Glycan-protein interactions are of utmost importance in several biological phenomena. Although the variety of carbohydrate residues in mammalian cells is limited to less than a dozen different sugars, their spatial topographical presentation in what is now associated as the "glycocodes" provides the fundamental keys for specific and high affinity "lock-in" recognition events associated with a wide range of pathologies. Toward deciphering our understanding of these glycocodes, chemists have developed new creative tools that included dendrimer chemistry in order to provide monodisperse multivalent glycoconjugates. This review provides a survey of the numerous aromatic architectures generated for the multivalent presentation of relevant carbohydrates using covalent attachment or supramolecular self-assemblies. The basic concepts toward their controlled syntheses will be described using modern synthetic procedures with a particular emphasis on powerful organometallic methodologies. The large variety of dendritic aromatic scaffolds, together with a brief survey of their unique biophysical and biological properties will be critically reviewed. The distinctiveness of the resulting multivalent glycoarchitectures, encompassing glycoclusters, glycodendrimers and molecularly defined self-assemblies, in forming well organized cross-linked lattices with multivalent carbohydrate binding proteins (lectins) together with their photophysical, medical, and imaging properties will also be briefly highlighted. The topic will be presented in increasing order of aromatic backbone complexities and will end with fullerenes together with self-assembled nanostructures, thus complementing the various scaffolds described in this special thematic issue dedicated to multivalent glycoscience.

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“…Haloforms (i.e., chloroform, bromoform, and iodoform) and diazirines are among the most used precursors to generate carbenes upon activation with a strong base and light irradiation, respectively. 9−12 Functionalized diazirine-derived carbenes were used to modify carbon nanotubes, 13 diamond, 14 fullerene, 15 and graphene. 14,16 Similarly, aromatic azides can be cleaved to yield aromatic nitrenes, which can readily react with a carbon−carbon double bond from the graphene to yield the corresponding aziridine appendages linked to graphene.…”

Section: Introductionmentioning

confidence: 99%

Density Functional Theory Investigation of Graphene Functionalization with Activated Carbenes and Its Application in the Sensing of Heavy Metallic Cations

et al. 2021

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Anthropogenic activities presently generate undesirable industrial and house waste byproducts such as heavy metallic cations (HMCs), which are then often released into the environment, despite being harmful to human beings. Developing new materials that can detect and capture HMCs is therefore highly desirable for wastewater remediation, especially if using cheap starting raw materials such as carbon. To shed theoretical light in this direction, we use density functional theory simulations to study the functionalization of pristine graphene with prototypical carbenes, RC(O)CH, with R = −OCH 3 (2a), −OH (2b), −ONa (2c), and −Ph (2d), and explore their use in sensing and capturing toxic HMCs (here, we focus on the most common and harmful ones: Cd 2+ , Hg 2+ , and Pb 2+ ). We first demonstrate that, starting from activated diazomethanes, RC(O)CHN 2 (1a−d), and graphene as precursors, it is possible to yield substituted cyclopropanes tethered to graphene, here modeled as a 6 × 6 supercell (g6×6), via a [2 + 1]cycloaddition reaction. Projected density of states and band structure calculations show that the cycloaddition reaction induces a band gap opening of the graphene, which can be used to tune it for electronic sensing devices. These nanomaterials (g6×6/3a−d) favorably interact with the metallic cations through coordination bonds with interaction energies varying from −1.18 to −2.75 eV. Differences in the electronic charge density following HMC adsorption reveal regions of electron depletion or gain induced by these interactions. Based on energetic and electronic structure analysis, we suggest that g6×6/3b−d are good candidates to detect HMCs. All the four nanomaterials show a higher affinity toward Pb 2+ , as rationalized by a synergic interaction with the graphene substrate, suggesting that they can be used for Pb 2+ sensing and removal. Notably, we demonstrate that once and only once the proper computational approach is employed, the accuracy of our predictions of a larger interaction strength of Pb 2+ with respect to Cd 2+ is validated via the agreement with available experimental data on g6×6/3b. Finally, we predict that by varying the pH, the g6×6/3b,c pair can be employed to differentially sense Cd 2+ and Hg 2+ cations.

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Synthesis of Endohedral Metallofullerene Glycoconjugates by Carbene Addition

Cited by 16 publications

References 42 publications

Recent progress in the chemistry of endohedral metallofullerenes

Recent progress in the chemistry of endohedral metallofullerenes

Multivalent glycoconjugate syntheses and applications using aromatic scaffolds

Density Functional Theory Investigation of Graphene Functionalization with Activated Carbenes and Its Application in the Sensing of Heavy Metallic Cations

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