Reductive Benzylation of Dimetallo Hexaaryl[70]Fullerenes on the Equatorial Region

Dianions of dimetallic hexa(organo)[70]fullerene [(C₅R₅)₂Ru₂C₇₀Ar₆]^2? (R=H, Me; Ar=Ph, 4‐MeC₆H₄, 4‐tBuC₆H₄) react with benzylic bromide to yield the dibenzylated product dimetallic octa(organo)[70]fullerene (C₅R₅)₂Ru₂C₇₀Ar₆(CH₂Ar′)₂ (Ar′=Ph, 4‐MeO₂CC₆H₄), where the benzylic groups are attached to the equatorial belt region of [70]fullerene; this region is generally considered to be rather unreactive. This unusual structure was unambiguously determined by X‐ray crystallography. Theoretical studies on the electronic properties of the monoanionic intermediate indicated that the highest spin density resides on the two carbon atoms in the belt region; one of them then couples with a benzylic radical to yield the octa(organo)fullerene product after ionic substitution of the fullerene anion with a benzylic bromide. Electrochemical analysis of the hexa(organo) and octa(organo) ruthenium complexes suggests that the modification of the belt region does not affect the electronic communication between the two metal centers.     

Synthesis of well‐defined and end‐polymerizable star‐shaped polysulfides and their application to negative photoresist

Various star‐shaped poly(phenoxy propylene sulfide)s (PPSs) bearing curable end groups were synthesized by the functionalization of the propagating ends of star‐shaped poly(PPS) with various electrophilies. The functionalization with chloromethyl styrene proceeded quantitatively, and afforded polymers with M_n almost agreed with theoretical value and narrow M_w/M_n. The photocuring conditions were optimized, and the addition of 10 wt % of poly(ethylene glycol) diacrylate was effective to attain sufficient crosslinking. The photocuring reaction of the end‐functionalized poly(PPS) films cast on silicon wafers was conducted by UV irradiation. The cured poly (PPS)s became insoluble in THF, supporting the sufficient crosslinking. Developing of a cured polymer yielded a negative photoresist pattern. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

The effect of specific surface area of TiO<Subscript>2</Subscript> on the thermal decomposition of ammonium perchlorate

The thermal decomposition of ammonium perchlorate (AP) is considered to be the first step in the combustion of AP-based composite propellants. In this report, the effect of the specific surface area of titanium oxide (TiO₂) catalysts on the thermal decomposition characteristics of AP was examined with a series of thermal analysis experiments. It was clear that the thermal decomposition temperature of AP decreased when the specific surface area of TiO₂ increased. It was also possible that TiO₂ influences the frequency factor of AP decomposition because there was no observable effect on the activation energy.     

Evaluating a time-delay of hydrogen production quantitatively in photosynthetic bacteria for stabilizing intermittency

Renewable energy is regarded as a clean energy source but has some problems, one of which is intermittency. To reduce this, the time-delay of hydrogen production by photosynthetic bacteria can be effective. In this study, we qualitatively evaluated the time-delay of hydrogen production by photosynthetic bacteria under various irradiation conditions, and we also quantitatively evaluated it by fitting the experimental data and the hydrogen production model with a genetic algorithm. As a result of model fitting, we found that the relationship between the lengths of the optimized time-delay of hydrogen production by photosynthetic bacteria and the amount of light irradiation is linear. And we also found that the time-delay of hydrogen production by photosynthetic bacteria had an upper limit under low light intensity. We have suggested the existence of an energy store mechanism in photosynthetic bacteria.     

Photoelectrochemical starch-O<Subscript>2</Subscript> biofuel cell consisting of chlorophyll derivative-sensitized TiO<Subscript>2</Subscript> anode and enzyme-based cathode

A new photoelectrochemical starch-O₂ biofuel cell has been developed, consisting of chlorin-e₆ (Chl-e₆) adsorbed on a TiO₂ layer onto an optical transparent conductive glass electrode as a photoanode, bilirubin oxidase (BOD)-modified electrode as a cathode, and a solution containing starch, glucoamylase, glucose dehydrogenase and NAD⁺ as fuel. The short-circuit photocurrent and the open-circuit photovoltage of this cell are 9.0 μA cm^?2 and 530 mV, respectively. The maximum power, FF and \(\eta\) values are estimated to be 1.7 μW cm^?2, 0.36 and 0.0017 %, respectively. Thus, this new type of the photochemical starch-O₂ biofuel cell has been developed by using the visible light photosensitization of Chl-e₆ on a TiO₂ film photoanode.     

Silver‐Catalyzed Allylation of Ketones and Intramolecular Cyclization through Carbene Intermediates from Cyclopropenes Under Ambient Conditions

Tandem C?C bond formation was achieved through silver‐catalyzed ring‐opening of cyclopropenes via carbene intermediates. The reaction of cyclopropenes in the presence of a silver catalyst gave indene derivatives under ambient conditions. In contrast, the insertion of organozinc reagents to silver carbene or allylic cation intermediates afforded allylmetal intermediates for the tandem allylation of carbonyl compounds.     

Synthesis of 10-nm scale oligothiophene molecular wires bearing anchor units at both terminal positions

Oligothiophenes with the length of ca.10 nm bearing anchor units (a protected thiol group or trimethylsilylethynyl) at both terminal positions in the conjugated backbone have been synthesized by the block-coupling synthetic strategy. Their electronic properties were clarified by spectroscopic and electrochemical measurements.     

Chemoenzymatic synthesis of (+)-totarol, (+)-podototarin, (+)-sempervirol, and (+)-jolkinolides E and D

The enzymatic resolution products [(1R,4aR,8aR)-1,2,3,4,4a,5,6,7,8,8a-decahydro-5,5,8a-trimethyl-2-oxo-trans-naphthalene-1-methanol-2-ethylene acetal (8aR)-7 (98% ee) and {acetate of (1S,4aS,8aS)-1,2,3,4,4a,5,6,7,8,8a-decahydro-5,5,8a-trimethyl-2-oxo-trans-naphthalene-1-methanol-2-ethylene acetal} (8aS)-9 (>99% ee)] obtained by the lipase-catalyzed enantioselective acetylation of (±)-7 in the presence of vinyl acetate as an acyl donor were converted to the ,β-unsaturated ketones (8aR)-6 and (8aS)-6, respectively. Concise syntheses of (+)-totarol 1, (+)-podototarin 2 and (+)-sempervirol 3 were achieved based on Michael reactions between (8aS)-6 and the appropriate β-keto ester followed by aldol condensation. The first chiral syntheses of (+)-jolkinolides E 4 and D 5 were achieved from (5R,10R,12R)-12-hydroxypodocarpa-8(14)-en-13-one 15 derived from (8aR)-6.