Publications by authors named "Tsukasa Nakahodo"

Unsymmetric boron (III) subphthalocyanines with a triselenole ring or a diselenete ring and eight fluoro groups were prepared by the reaction of 5,6-dicyano-4,7-diethylbenzo-[1,2,3]triselenole and tetrafluorophthalonitrile with trichloroborane in xylene. The reaction was accompanied by a contraction of the triselenole ring to the diselenete ring. The substrate, dicyanobenzo[1,2,3]triselenole, was prepared by a new procedure via a photolytic demethylenation reaction of 3,7-diethyl[1,3]diselenolophthalonitrile using a 10 W white LED light.

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A series of ()-1,2-diaryldigermenes, (Eind)ArGeGeAr(Eind) [Ar = phenyl (2), thiophen-2-yl (3), 9,9-dimethyl-2-fluorenyl (4) and 2,2'-bithiophen-5-yl (5)], supported by the fused-ring bulky 1,1,3,3,5,5,7,7-octaethyl--hydrindacen-4-yl (Eind) groups, have been obtained as yellow-orange to red crystalline solids by the reaction of 1,2-dibromodigermene, (Eind)BrGeGeBr(Eind) (1), with ArLi. In the crystals of 2-5, the digermene cores show a flexible nature adopting a -bent geometry with the -bent angles () between the Ge-Ge vector and the C-Ge-C plane of 34.04(12)° (2), 38.

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2,5-Diphenyl-3,4-dicyanothiophene (1) and phthalonitrile (2) were mixed and treated with ruthenium (III) trichloride, 4-methylpyridine, and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in 2-ethoxyethanol at 135°C, to produce low-symmetrical tetraazaporphyrins (TAPs) (3), (4), (5), and (6) with one to three thiophene rings.

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A chiral phosphine cavitand 1 induced the formation of chiral metal (Ru, Rh, Pd, Ag, Pt, and Au) nanoparticles (NPs). The ligand 1 of the chiral metal NPs prevents both thermal racemization and ligand exchange with a thiol, but the organic molecules can react with the metal surfaces. In contrast to the 1-protected Au NPs, the BINAP-protected Au NPs easily undergo ligand exchange and thermal racemization with aggregation.

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We determined the surface-enhanced Raman scattering of the plasmonic hybrid nanotubes of fullerene C60-polythiophene-Ag or Au nanoparticles (NPs) which were synthesized via the template-based electrocopolymerization of terthiophene-linked fullerene C60 and terthiophene-modified Ag NPs or Au NPs using a nanoporous alumina membrane as the template. The combination of plasmonic activity and chemical stability may allow for a variety of new applications.

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The first isolable benzo-1,2-diselenete, 4,5-dicyano-3,6-diethylbenzo-1,2-diselenete (4), was prepared by the reaction of 4,5-(o-xylylenediseleno)-3,6-diethylphthalonitrile (3) with aluminum chloride in toluene. X-ray crystallographic analysis demonstrated that 4 contains a trapezoidal diselenide ring rather than a benzo-1,2-diselenone structure. In crystal form, 4 undergoes self-assembly and generates structures based on layered molecular sheets since the unit cell contains only one molecule.

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Endohedral metallofullerene glycoconjugates were synthesized under mild conditions by carbene addition using appropriate glycosylidene-derived diazirine with La(2)@I(h)-C(80). NMR spectroscopic studies revealed that the glycoconjugate consists of two diastereomers of [6,6]-open mono-adducts. The electronic properties were characterized using Vis/NIR absorption spectroscopy and electrochemical measurements.

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New chiral magnetite nanoparticles with a polymerizable group produced polymer composite films on an electrode surface and the hybrid nanotubes of magnetite nanoparticles and polythiophene from their template-based electropolymerization.

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We report the encapsulation of negatively charged Au nanoparticles and anionic fluorescent (FL) dye in the inner cavity of redox-active cationic polymer nanotubes with viologen via electrostatic interaction and the release of the FL dye from the FL dye confined in the cavity of the polymer nanotubes by electrochemical and chemical reduction.

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New heterosegment-junctioned hybrid nanotubes of polythiophene and heterometallic nanoparticles (Pd, Au NPs) have been synthesized by sequential electropolymerization of terthiophene-modified Pd and Au NPs in a nanoporous template.

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In the course of our study of the development of a synthetic methodology for the aziridination of fullerenes, we recently reported the photochemical [2+1] cycloaddition reaction of nitrene onto C(60) generated from sulfilimine. Sulfilimines with an electron-donating group on the N atom are well known to undergo Michael-type reactions, followed by concomitant elimination of sulfide to afford the corresponding aziridines. In these reactions, sulfilimines act as a nucleophile to the electrophilic olefins.

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Photochemical reactions of C(60) with siliranes (1a-d) afford adducts of four types (2a-5b) as carbosilylated and hydrosilylated C(60) derivatives. Characterization of these adducts was conducted using MS, UV, NMR spectroscopy, and single-crystal X-ray analyses. In particular, the first example of the crystal structure of a closed 1,2-adduct at the 5,6-ring junction of the C(60) cage is provided by single-crystal X-ray analysis of 3b.

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We report here the results on single crystal X-ray crystallographic analysis of the Gd@C82 carbene adduct (Gd@C82(Ad), Ad = adamantylidene). The Gd atom in Gd@C82(Ad) is located at an off-centered position near a hexagonal ring in the C2v-C82 cage, as found for M@C82 (M = Sc and La) and La@C82(Ad). Theoretical calculation also confirms the position of the Gd atom in the X-ray crystal structure.

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Fullerenes violating the isolated pentagon rule (IPR) are only obtained in the form of their derivatives. Since the [5,5]-bond carbons are highly reactive, they are easily attacked by reagents to release the bond strains. Non-IPR endohedral metallofullerenes, however, still have unsaturated sp (2) carbons at the [5,5] bond junctions, which allow their chemical properties to be probed.

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The photochemical reaction of La@C82(Cs) with 2-adamantane-2,3-[3H]-diazirine (1) affords the adduct 2 of La@C82(Cs) with adamantylidene (Ad:) in a high selectivity. The two isomers of La@C82(Cs)(Ad), 2a and 2b, are isolated by HPLC and characterized by electron spin resonance, mass, and UV-vis-near-infrared spectroscopies. The electronic properties of 2a and 2b are very similar to that of the pristine La@C82(Cs), suggesting that 2a and 2b retain the essential electronic and structural character of La@C82(Cs).

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Thermal and photochemical reactions of La2@C78 with 2-admantane-2,3-[3H]-diazirine are investigated. Four isomers of the monoadduct (La2@C78Ad) synthesized by the photoreaction are isolated by HPLC and characterized by mass, UV-vis-NIR absorption, cyclic voltammogram and differential pulse voltammogram spectroscopy, proton and 13C NMR spectroscopic analysis, single-crystal X-ray diffraction analysis, and theoretical approaches. The addition reactions occur at both the [5,6] and [6,6] positions.

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The (139)La NMR study of the exohedrally functionalized derivatives of La(2)@C(80) metallofullerene, La(2)@C(80)(Ar(2)Si)(2)CH(2) (: Ar = Mes, Mes = mesityl, : Ar = Dep, Dep = 2,6-diethylphenyl), reveal that the two La atoms hop between two sites along the equator of the C(80) cage.

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We show here that La@C72 has a non-IPR cage, unique electronic properties, and high reactivity by the spectroscopic and X-ray crystallographic analysis and the theoretical study. The isolation of La@C72 as a stable derivative might constitute an important stepping-stone on the way to isolation of these unknown metallofullerenes and open new material science of metallofullerenes.

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The photochemical reaction of Sc(3)N@C(80) with 1,1,2,2-tetramesityl-1,2-disilirane affords the adduct as a bis-silylated product. The adduct was characterized by NMR spectroscopy and single-crystal X-ray structure analysis. The dynamic behavior of the disilirane moiety and the encapsulated Sc(3)N cluster were also investigated.

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Although Sc2C84 has been widely believed to have the form Sc2@C84, the present 13C NMR study reveals that it is a scandium carbide metallofullerene, Sc2C2@C82, which has a C82(C(3v)) cage.

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Complexation of endohedral metallofullerene La@C(82)-A (1) with macrocyclic compounds, such as 1,4,7,10,13,16-hexaazacyclooctadecane (2), 1,4,7,10,13,16-hexamethyl-1,4,7,10,13,16-hexaazacyclooctadecane (3), mono-aza-18-crown-6 ether (4), 18-crown-6 ether (5), and p-tert-butylcalix[n]arenes (n = 4-8, 6-10), for the first time is examined. Among them, 1 forms a complex with azacrown ethers 2-4 while accompanying the electron transfer between them. This is characteristic of endohedral metallofullerene and caused by its low reduction potential.

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