Hiroyuki Isobe

Discrete graphitic carbon compounds serve as tunable models for the properties of extended macromolecular structures such as nanotubes. Here, we report synthesis and characterization of a cylindrical C₃₀₄H₂₆₄ molecule composed of 40 benzene (phenine) units mutually bonded at the 1, 3, and 5 positions. The concise nine-step synthesis featuring successive borylations and couplings proceeded with an average yield for each benzene-benzene bond formation of 91%. The molecular st

A new triazole-linked analogue of DNA ((TL)DNA) has been designed and synthesized using click chemistry. The chain elongation reaction using copper-catalyzed Huisgen cycloaddition was successful and gave the artificial oligonucleotide that formed a stable double strand with the complementary strand of natural DNA.

The risk assessment of carbon materials, an important topic in nanomaterials research, has been hampered by the lack of characterizable samples. Transition-metal-free carbon nanohorn aggregates have been prepared that are covalently bonded aggregates of single-walled nanotubes. They were functionalized to give water-soluble derivatives (see picture), which were incubated with cells in cytotoxicity assessments. Supporting information for this article is available on the WWW under http://www.wiley

A carbonaceous bearing of a minimal form has been assembled using a finite carbon nanotube molecule and a functionalised fullerene molecule. With the van der Waals attraction, the bearing holds the fullerene journal tightly to prevent its run-out motion, and the journal with a shaft rolls anisotropically in the bearing despite the tight holding constraint. Ensemble motion has been revealed spectroscopically at the molar quantity level.

Synthesis of diphenyl cucurbit[6]uril (CB[6]) has been achieved via co-oligomerization of diphenyl glycoluril and unsubstituted glycoluril. The unsymmetrically substituted CB[6], Ph(2)CB[6], was further converted to a rotaxane incorporating bis(dinitrophenyl)spermine. [reaction: see text]

Twisted carbon nanobelts could display persistent chirality, which is desirable for material applications, but their synthesis is very challenging. Herein, we report the successful synthesis and chiral resolution of such a kind of molecules (1-H and 1) with a figure-eight configuration. 1-H was synthesized first by macrocyclization through Suzuki coupling reaction followed by benzannulation via Bi(OTf)3-mediated cyclization reaction of vinyl ether. Oxidative dehydrogenation of 1-H gave the fully

A series of aminofullerenes that share a common structural motif have been synthesized and subjected to a systematic investigation of structure activity relationship regarding their ability for transient transfection and cytotoxicity. DNA-binding tests indicated that any water-soluble fullerene-bearing amino group would bind to double-stranded DNA. For these molecules to be effective transfection reagents, however, they require additional structural features. First, the molecule must be capable

The reaction of [60]fullerene with a variety of a secondary aliphatic amines in 20% v/v dimethyl sulfoxide in chlorobenzene under an atmospheric pressure of molecular oxygen allows regioselective introduction of four amino groups and one epoxide group around one pentagon of the fullerene molecule in good to high yield. This new synthesis of tetraaminofullerene expoxide can be carried out with a simple procedure on a multigram scale at room temperature and affords a variety of functionalized full

The synthesis of fullerene-carbohydrate conjugates using a copper-catalyzed [3+2] cycloaddition reaction to facilitate the union of an azido-functionalized sugar and a pentaalkynyl[60]fullerene is straightforward. Thus, fullerenes bearing five oligosaccharides such as Gb3-trisaccharide can be readily accessed. Nanometer-scale molecular architectures presenting as many as 15 sugar moieties in C5-symmetry are readily produced. The cycloaddition reaction proceeds quantitatively under mild condition

Mothball macrocycles: Naphthalene has been coupled to form macrocylic oligomers composed of five, six, and seven naphthalene units (see picture). Thermally stable macrocycles bearing 50, 60, or 70 π electrons within the hydrocarbon structure form columnar assemblies in crystals and serve as bipolar carrier transport materials in organic light-emitting diode devices.

A fullerene derivative bearing two diamino side chains binds to a plasmid vector DNA, either 4 or 40 kbp in size, delivers it to mammalian cells on incubation, and leads to expression of the encoded gene either transiently or stably. The initial physicochemical investigations upon DNA-binding and protective properties of various fullerene compounds against nuclease led us to identify the tetraamino fullerene as an ideal candidate to probe the new concept of fullerene-mediated gene delivery to ma

A secondary amine undergoes a one-step multiple addition to [60]fullerene under photochemical aerobic conditions to produce tetra(amino)fullerene epoxide 1 in moderate to excellent yield.

Attachment of small molecules to large biomolecules can occur through a supramolecular three-body modular-binding scheme (see scheme). This approach allows cucurbit[6]uril (C), which normally cannot bind to DNA, to be attached to double-stranded DNA (A) through a linker molecule (B) containing both an acridine moiety (which binds to DNA) and a spermine moiety (which binds cucurbit[6]uril).

Ascending and Descending: A combination of two helical molecules and two twisting covalent axes in the form of a macrocycle conjures an illusory molecular object that has a seemingly impossible molecular structure, that is, an endlessly descending circle that consists of an sp2-carbon network, which can be regarded as the molecular expression of Penrose stairs (see picture). Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-revi

The recent development of cyclo-para-phenylenes has demonstrated the feasibility of radial π systems in nanohoop structures, especially in the crystalline state. However, in contrast to macrocyclic molecules with benzene units, which have a several-decades-long history, macrocycles composed solely of naphthylene units (the smallest acene) have been much less explored. Although two examples of cyclonaphthylenes have been reported to date, neither possesses a radial π system. We herein report the