Fabrication of a carbon nanotube device using a patterned electrode and a local electric field

Suspensions of carbon nanotubes (CNTs) and organic solvent were dropped onto a substrate which had patterned electrodes while applying a DC voltage between the electrodes. Both multiwall and single-wall (SW) CNTs were purified from the mixture of CNTs and the undesirable particles of carbon when the solvent dichloromethane was used at high temperature. It is found that a SW CNT bridges the gap of the electrodes. This enables us to fabricate CNT devices at a controlled position.     

Sulfoximidoyl radical. Homolytic addition of n-halosulfoximides to olefins

Homolytic addition reaction of N-halosulfoximides, i.e., diphenyl-N-chloro sulfoximide($\text{1}$), diphenyl-bromosulfoximide($\text{2}$), and methylphenyl-N-chloro-sulfoximide($\text{3}$), to such olefins as tert-butylethylene and cyclohexene was found to afford the corresponding N-alkylated sulfoximides, which are presumed to be formed via the initial addition of the sulfoximidoyl radical.     

Mechanism of Remote Conjugate Addition of Lithium Organocuprates to Polyconjugated Carbonyl Compounds

Regioselective reaction of a lithium organocuprate (R₂CuLi) and a polyconjugated carbonyl compound affords a remote‐conjugate‐addition product. This reaction proceeds particularly cleanly when the conjugation is terminated by a C? C triple bond. The reaction pathways and the origin of the regioselectivity of this class of transformations are explored with the aid of density functional calculations. The outline of the reaction pathway is as follows. An initially formed β‐cuprio(III) enolate intermediate undergoes smooth copper migration along the conjugated system. This process takes place faster than reductive elimination of intermediary σ/π‐allylcopper(III) species, since the latter reaction disrupts the conjugation in the substrate and hence is not preferred. The copper migration to the acetylenic terminal affords a σ/π‐allenylcopper(III) intermediate, which undergoes facile and selective C? C bond forming reductive elimination at the terminal carbon atom. The present mechanistic framework shows good agreement with some pertinent experimental data, including ¹³C NMR chemical shifts and kinetic isotope effects.     

A singly bonded derivative of endohedral metallofullerene: La@C82CBr(COOC2H5)

A novel Bingel monoadduct of La@C82 (mono-A) has been synthesized by the reaction with diethyl bromomalonate in the presence of DBU (Bingel-Hirsch reaction). Its structure has been fully determined by NMR spectroscopic and X-ray crystallographic analyses. The most distinct feature of mono-A is the single bond moiety between the functional group and fullerene cage, which is very different from the cyclopropane moiety in a conventional Bingel adduct of empty fullerenes. Further spectroscopic characterizations and calculations revealed the closed-shell structure of mono-A. Its formation mechanism was discussed according to calculation results.     

Preparation of polystyrene/poly(methyl methacrylate) composite particles having a dent

Nonspherical polystyrene (PS)/poly(methyl methacrylate) (PMMA) composite particles having a dent were prepared by releasing toluene from PS/PMMA/toluene droplets dispersed in a poly(vinyl alcohol) aqueous medium. An ex-centered PS-core/PMMA-shell morphology, in which a part of the PS core contacted with the aqueous medium and toluene partitioned more in the PS core than in the PMMA shell, was formed in the polymers/toluene droplet in the process of phase separation therein with releasing toluene. The volume of the dent became bigger with an increase in the PS content and in the toluene content partitioned in the PS core.Part CCLXI of the series Studies on Suspension and Emulsion.     

Reaction of singlet oxygen with azines: Implications for dioxirane intermediate

Photooxygenation of tricyclo[3.3.1.1]decanone azine (adamantanone azine) afforded, in addition to adamantanone, 4-oxahomoadamantan-5-one derived from a dioxirane intermediate via a non-radical pathway.     

Structural determination of metallofullerene Sc3C82 revisited: a surprising finding

We report here the structural determination of the Sc3C82 molecule by 13C NMR spectroscopy and X-ray single-crystal structure analysis. From the present study, it is obvious that the structure of Sc3C82 is not Sc3@C82 but Sc3C2@C80.     

Picosecond IR-UV pump-probe spectroscopic study of the dynamics of the vibrational relaxation of jet-cooled phenol. II. Intracluster vibrational energy redistribution of the OH stretching vibration of hydrogen-bonded clusters

A picosecond time-resolved IR-UV pump-probe spectroscopic study has been carried out for investigating the intracluster vibrational energy redistribution (IVR) and subsequent dissociation of hydrogen-bonded clusters of phenol (C6H5OH) and partially deuterated phenol (C6D5OH, phenol-d5) with various solvent molecules. The H-bonded OH stretching vibration was pumped by a picosecond IR pulse, and the transient S1-S0 UV spectra from the pumped level as well as the redistributed levels were observed with a picosecond UV laser. Two types of hydrogen-bonded clusters were investigated with respect to the effect of the H-bonding strength on the energy flow process: the first is of a strong "sigma-type H-bond" such as phenol-(dimethyl ether)(n=1) and phenol dimer, and the second is phenol-(ethylene)(n=1) having a weak "pi-type H-bond." It was found that the population of the IR-pumped OH level exhibits a single-exponential decay, whose rate increases with the H-bond strength. On the other hand, the transient UV spectrum due to the redistributed levels showed a different time evolutions at different monitoring UV frequency. From an analysis of the time profiles of the transient UV spectra, the following three-step scheme has been proposed for describing the energy flow starting from the IVR of the initially excited H-bonded OH stretching level to the dissociation of the H bond. (1) The intramolecular vibrational energy redistribution takes place within the phenolic site, preparing a hot phenol. (2) The energy flows from the hot phenol to the intermolecular vibrational modes of the cluster. (3) Finally, the hydrogen bond dissociates. Among the three steps, the rate constant of the first step was strongly dependent on the H-bond strength, while the rate constants of the other two steps were almost independent of the H-bond strength. For the dissociation of the hydrogen bond, the observed rate constants were compared with those calculated by the Rice, Ramsperger, Kassel, and Marcus model. The result suggests that dissociation of the hydrogen bond takes place much faster than complete energy randomization within the clusters.