Sho-ichi Iwamatsu

Putting Ammonia into a Chemically Opened Fullerene

We put ammonia into an open-cage fullerene with a 20-membered ring ( 1) as the orifice and examined the properties of the complex using NMR and MALDI-TOF mass spectroscopy. The proton NMR shows a broad resonance corresponding to endohedral NH 3 at delta H = -12.3 ppm relative to TMS. This resonance was seen to narrow when a (14)N decoupling frequency was applied. MALDI spectroscopy confirmed the presence of both 1 ( m/ z = 1172) and 1 + NH 3 ( m/ z = 1189), and integrated intensities of MALDI peak trains and NMR resonances indicate an incorporation fraction of 35-50% under our experimental conditions. NMR observations showed a diminished incorporation fraction after 6 months of storage at -10 degrees C, which indicates that ammonia slowly escapes from the open-cage fullerene.

Methane in an open-cage [60]fullerene.

An endohedral methane complex of a fullerene derivative is first synthesized by insertion of a methane molecule through the opening of an open-cage C(60) derivative. The trapped methane is confirmed by NMR spectroscopy and mass spectrometry. Both methane carbon and protons show remarkable upfield shifts in NMR, characteristic of a chemical species in a fullerene cage. CH(4) protons appear as one equivalent signal in the (1)H NMR spectrum, suggesting that even methane can rotate in a C(60) cage.

Copper-catalyzed facile carbon-carbon bond forming reactions at the α- position of α,α,γ-trichlorinated γ-lactams

Abstract Treatment of α,α,γ-trichlorinated γ-lactams with a catalytic amount of CuCl(bipyridine) complex resulted in facile activation of their carbon-chlorine bond at the α-position. Addition of the carbon moiety and the chlorine atom to olefins furnished the carbon-carbon bond forming reaction at the α-position of the carbonyl group. In certain trichlorinated γ-lactams including a carbon-carbon double bond at an appropriate position, intramolecular addition reactions took place to give bicyclic lactams. Sequential reactions consisting of the cyclization of N-allyl trichloroacetamides followed by the inter- or intramolecular carbon-carbon bond forming reactions at the α-position of the lactams were also achieved. Efficiency of the catalyst and reaction rate was dependent on the protecting group of the nitrogen atom of the γ-lactams; N-tosyl derivatives gave better results than the corresponding N-benzyl homologues. The molecular structure of the representative products revealed the stereochemical outcome of the reactions.

Photooxygenative partial ring cleavage of bis(fulleroid): synthesis of a novel fullerene derivative with a 12-membered ring

Abstract Photooxidation of tetrasubstituted bis(fulleroid) derivatives gives novel diketone derivatives with 12-membered rings on the surface of fullerene in high yields.

A novel migrative addition reaction of hydrazines to the diketone derivative of C60Electronic supplementary information (ESI) available: experimental procedures and characterisation data; computational procedures and Cartesian coordinates of 3a-I. See http://www.rsc.org/suppdata/cc/b3/b302080k/

A novel addition reaction of an aromatic hydrazine to the diketone derivative of C60 occurs highly regioselectively with an unusual migration of two hydrogen atoms from the hydrazine to the fullerene and affords a fluorescent product having a methylene carbon along the orifice.

Kinetics and solvent-dependent thermodynamics of water capture by a fullerene-based hydrophobic nanocavity.

Kinetic and thermodynamic properties of water encapsulation from organic solution by an open-cage [60]fullerene derivative have been investigated. 2D exchange NMR spectroscopy (EXSY) measurements were employed to determine the association and dissociation constants at 300-330 K (k(a) = 4.3 M(-1) × s(-1) and k(d) = 0.42 s(-1) at 300 K) in 1,1,2,2-tetrachloroethane-d(2) as well as the activation energies (E(a,ass) = 27 kJ mol(-1), E(a,diss) = 50 kJ mol(-1)). The equilibrium constants and thermodynamic parameters in various solvents (benzene-d(6), 1,2-dichlorobenzene-d(4), and dimethylsulfoxide-d(6)) were estimated using 1D-(1)H NMR spectroscopy. The parameters were dependent on the polarity of the solvent; ΔH depended linearly on the solvent polarity, becoming increasingly unfavorable as polarity increased. Mixtures of polar dimethylsulfoxide-d(6) in less polar 1,1,2,2-tetrachloroethane-d(2) showed a similar trend.