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The incorporation of electron-accepting units into π-conjugated systems can allow the modulation of the physical properties and frontier orbital energy levels of the molecules. An electron-accepting π-conjugated compound (CNNTz-TR) containing cyano-substituted naphthobisthiadiazole (CNNTz) was synthesized via a nucleophilic substitution reaction as the key step. Owing to the presence of the cyano groups, CNNTz-TR affords a low-lying lowest unoccupied molecular orbital energy level. Organic solar cells based on the blend films of CNNTz-TR and a low-bandgap donor exhibited moderate power conversion efficiencies. The results showed that embedding the CNNTz unit into the π-conjugated backbone is an effective approach for designing electron-accepting semiconducting materials.

A composite powder of titanium oxide and silver nanoparticles was obtained by using a combination of the sol–gel process and ultraviolet light induced reduction of silver ion via one-pot synthesis. After calcination, silver nanoparticles were embedded in an anatase crystalline titanium oxide matrix, as revealed by transmission electron microscopy. Silver nanoparticles with sizes ranging from a few nanometers to several tens of nanometers were observed in the titanium oxide matrix. The crystalline titanium oxide-silver nanoparticle composite powder decomposed the methylene blue dye upon visible light irradiation. The decomposition rate of the dye using the crystalline titanium oxide-silver nanoparticle composite powders was considerably faster than that in the case of the reference titanium oxide powder without silver nanoparticle. Thus, plasmon-induced charge separation from the silver nanoparticle to the conduction band of titanium oxide expected to occur, and holes on silver nanoparticles or induced active oxygen decomposed methylene blue in the solution or adsorbed on titanium oxide.

Benzene is oxidized to phenol by TiO2-photocatalytic reaction in liquid benzene. However, this reaction decelerates as the reaction is continued because the TiO2 surface is gradually covered with t...

This study examines mentor teachers’ learning through supervisory experiences of mentees’ teaching portfolios and collaborative peer-mentoring meetings with other mentors, in the context of developing mentors’ reviewing skills and awareness as professional mentors during an intensive workshop. Qualitative analysis revealed the following three points: (1) mentors understood the importance of having an open attitude toward their mentees and effective communication techniques for encouraging mentees to reconsider their solutions; (2) mentors obtained additional information regarding their own mentors and second opinions from other mentors in peer-mentoring meetings; and (3) mentors benefited from other mentors’ management styles and reflected on their own expertise for engaging in effective mentorship in peer-mentoring meetings.

Ultrathin films consisting of titanium oxide and gold nanoparticles were prepared using a combination of the surface sol–gel process and liquid/liquid interfacial precipitation. The composite films had a titanium oxide/gold nanoparticle layer/titanium oxide film structure, comprising a gold nanoparticle thin-film layer sandwiched within titanium oxide films of nanometer-order thickness. Upon heating the titanium oxide–gold nanoparticle composite films to 450 °C, they underwent a phase change from the amorphous to the anatase phase, which was confirmed via Raman scattering analysis. It was observed that, even after heating, the plasmonic absorption band due to the presence of gold nanoparticles was maintained in the composite films. The photocatalytic degradation efficiencies of methylene blue dye were evaluated in films under 520 nm light irradiation. The results suggested that the sandwich-like structure of this titanium oxide/gold nanoparticle layer/titanium oxide is promising for the visible-light-induced degradation of methylene blue dye.

Photocatalytic reaction of trans-stilbene on TiO2 particles produces benzaldehyde with high selectivity in acetonitrile-water mixed solvent. Introduction of electron-donating substituents to the be...

Addition reaction between C60 and ethylenediamine occurred at room temperature in an ambient condition. C60-ethylenediamine adduct particles were prepared by mixing toluene solutions of C60 and ethyelenediamine. Average diameter of the C60-ethylenediamine adduct particles was changed non-linearly according to the reaction time, which were observed using transmission electron microscopy. Early stage of the reaction, the diameter of the adduct particles was changed from about 250 to about 430 nm. Then, the size of the adduct particles was converged to about 300 nm. During this addition reaction, the crystalline sizes of adduct particles were constant about 2–3 nm, regardless of the sizes of the adduct particles, which were determined by X-ray diffraction measurement.

Aromatic diacids such as diphenic acid and (E)-2-(2-carboxyvinyl)benzoic acid were converted into the corresponding lactones with high selectivity by decarboxylation via TiO2-photocatalytic reactions in acetonitrile solution containing 10% (v/v) water and molecular oxygen.

When benzene was oxidized on TiO2-photocatalysts, muconaldehyde as well as phenol was identified as a product. Muconaldehyde was not produced from phenol, indicating that muconaldehyde and phenol are produced as initial stable intermediates by independent pathways. The amount of muconaldehyde produced in the reaction solution was low because it was rapidly oxidized on the photocatalyst. The contributions of the two pathways to the mineralization of benzene were analyzed by isotopic tracing methods using labeled benzene (13C6H6) and labeled phenol (13C6H5OH). The results showed that a larger part (60–70%) of benzene is initially converted to muconaldehyde. The percentage was dependent on the properties of TiO2 powders. It was also found that anatase-form powders show higher activity for oxidation of benzene than rutile powders do, whereas rutile-form powders show higher activity for oxidation of phenol than anatase powders do.

Thirty-two glycoconjugated porphyrins were synthesized by a modification of Lindsey method in the presence of Zn(OAc)(2).2H(2)O as a template. The Zn(2+) ion template strategy improved the yield about three-fold in the case of meta-substituted tetraphenylporphyrins. In addition, free-base porphyrins were obtained almost quantitatively by demetalation with 4 M HCl. Sixteen deacetylated glycoconjugated porphyrins were tested as candidate photodynamic therapy (PDT) drugs using HeLa cells. Most of the deacetylated glycoconjugated porphyrins showed higher cellular uptake than tetraphenylporphyrin tetrasulfonic acid (TPPS), and 5,10,15,20-tetrakis[4-(beta-D-arabinopyranosyloxy)phenyl]porphyrin (p-5d) in particular showed 18.5-fold higher uptake than TPPS. The photocytotoxicity of 5,10,15,20-tetrakis[4-(beta-D-glucopyranosyloxy)phenyl]porphyrin (p-5a), p-5d and TPPS was examined with HeLa cells, using a light dose of 16 J/cm(2). These photosensitizers had no cytotoxicity in the dark, but their photocytotoxicity increased in the order of TPPSp-5ap-5d. These results suggest p-5d is a good candidate for a PDT drug.

Eight 5,10,15,20-tetrakis[3- or 4-(β- d -glycopyranosyloxy)phenyl]chlorins were synthesized by means of the Whitlock method with diimide reduction and purified by reversed-phase thin layer chromatography (RP-TLC). All compounds were characterized by 1H NMR spectroscopy, electron-spray ionization time-of-flight mass spectrometry (ESI-TOF MS), and UV–Vis spectroscopy. ESI-TOF MS could detect the 2H difference in molecular weight between a glycoconjugated chlorin and its corresponding porphyrin (i.e., 5,10,15,20-tetrakis[3- or 4-(β- d -glycopyranosyloxy)phenyl]porphyrin). The cellular uptake of the eight chlorins was evaluated in HeLa cells. All glycoconjugated chlorins showed higher cellular uptake than tetraphenylporphyrin tetrasulfonic acid (TPPS), and 5,10,15,20-tetrakis[3-(β- d -xylopyranosyloxy)phenyl]chlorin showed 50-fold higher uptake than TPPS. The photocytotoxicity of 5,10,15,20-tetrakis[3-(β- d -glucopyranosyloxy)phenyl]chlorin, 5,10,15,20-tetrakis[3-(β- d -xylopyranosyloxy)phenyl]chlorin and TPPS towards HeLa cells was examined at the concentration of 2 × 10−7 M (mol/dm3). These photosensitizers had no cytotoxicity in the dark, but their photocytotoxicity decreased in the order of 5,10,15,20-tetrakis[3-(β- d -glucopyranosyloxy)phenyl]chlorin > 5,10,15,20-tetrakis[3-(β- d -xylopyranosyloxy)phenyl]chlorin > TPPS. The results indicate that the photocytotoxicity is not related simply to cellular uptake.

Photocatalytic oxidation of naphthalene was investigated in a mixed solution of acetonitrile and water using various kinds of titanium dioxide (TiO 2 ) powders as the photocatalysts and molecular oxygen as the electron acceptor. The main product from naphthalene is 2-formylcinnamaldehyde. For this reaction, anatase small TiO 2 particles, which are commonly used as photocatalyst, are inactive, probably because band bending is necessary for the oxidation of naphthalene. If the particles are not extremely small, pure rutile and pure anatase powders show fairly high activity, and those containing both anatase and rutile phases show the highest activity. When a pure anatase powder is partly (about 90%) converted to the rutile form by heat treatment, the activity is largely enhanced. The activity of pure rutile particles is also enhanced by physically mixing them with a small amount of small-sized anatase particles, which are inactive for this reaction. These results can be explained by the synergism between rutile and anatase particles. We consider that electrons are transferred from rutile particles to anatase particles, i.e. naphthalene is mainly oxidized on rutile particles and oxygen is mainly reduced on anatase particles. This electron transfer process is supported by electrochemical properties of TiO 2 electrodes for reduction of oxygen.

In order to understand electron transfer (ET) pathways through bonds and through space, a porphyrin-spacer-benzoquinone molecule, where the spacer is spiro[4.4]nonane and a phenyl group is inserted between the space of the redox pair, was prepared. On the basis of MM2 calculation, the edge-to-edge distances between the phenyl and the porphyrin or quinone rings are in the range of 2.5—4.2 A. Therefore, it was expected that there are two possible intramolecular ET pathways in the compound, i.e., through bond and through space. The ET rates for charge separation process (kcs) were obtained on the basis of fluorescence lifetime. The kcs value of the above compound is almost identical with that of a reference compound in which no inserted phenyl ring is present. Therefore, it was concluded that the inserted π-system between the redox pair is not used as a stepping stone in ET pathways; in other words, ET in the present molecules takes place in a through-bond mechanism. To compete with fast ET with through-bond...

Two C60 units were covalently linked to 5,10-(cis-) or 5,15-(trans-) positions at a meso-tetraphenylporphyrin via pyrolidine spacers. 1H NMR, UV-visible absorption, and fluorescence spectroscopy showed that there is a considerable interaction among the chromophores in cis-isomers due to the close proximity of the two C60 moieties.

Reductive alkylation of aniline with acetone over various Pt catalysts was studied under atmospheric pressure of hydrogen at room temperature. It was found that our newly designed Pt catalyst, i.e....

C60 was covalently incorporated into hydrophobic cluster of amphiphilic polysulfonates. In this cluster C60 chromophores showed extremely blue-shifted fluorescence and no thermally activated delayed fluorescence.

Photophysical and photochemical properties of C60-pendant polymer in aqueous solution, in which C60 was covalently incorporated into polymer cluster (C60/unimer), have been studied by transient absorption spectroscopy. 3C60*/unimer was quenched by O2 in two routes; the initial fast decay component was increased by addition of a detergent. From these observations, kinetic models for the quenching are proposed.

Two C60 units were covalently linked to 5,10-(cis-) or 5,15-(trans-) positions at a meso-tetraphenylporphyrin via pyrolidine spacers. 1H NMR, UV-visible absorption, and fluorescence spectroscopy showed that there is a considerable interaction among the chromophores in cis-isomers due to the close proximity of the two C60 moieties.

Phenanthrene was converted into a coumarin compound by a TiO2-photocatalyzed reaction in an acetonitrile solution containing 8 wt% water and molecular oxygen in 45% yield.

In order to understand electron transfer pathways through bond and through space, a covalently linked porphyrin-quinone molecule with an inserted phenyl ring between the redox pair was prepared. The inserted π-system is not used as a stepping stone in electron-transfer pathways.

Pyromellitimide-linked zincporphyrin dyad was covalently incorporated into hydrophobic cluster of amphiphilic polysulfonate. Accelerated photoinduced electron transfer of the dyad in the copolymer was observed as compared with that of the corresponding dyad in THF, indicating the large contribution of the constrained microenvironment for electron transfer.

Photodynamic therapy (PDT) is one of the most effective treatments for cancer. We synthesized and characterized a series of 16 glycoconjugated porphyrins using a modification of the Lindsey method in the presence of Zn ( OAc )2·2 H 2 O as a template. The Zn 2+ ion template strategy improved the yield about 3-fold in the case of meta-substituted tetraphenylporphyrins, and free-base porphyrins were obtaind almost quantitatively by demetalation with 4 M HCl . The hydrophobicity parameter (Log P) of these porphyrins was evaluated by reversed phase high-performance liquid chromatography (RP-HPLC). The Log P values ranged from +4.8 to +7.8, so that most of the compounds are amphiphilic. The effect of the glycopyranosyl unit on the hydrophobicity of these compounds is discussed on the basis of the Log P value.