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Volume 88
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Award Accounts
The Chemical Society of Japan Award for Young Chemists for 2010
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Naoki Aratani, Atsuhiro Osuka2015 Volume 88 Issue 1 Pages 1-27
Published: January 15, 2015
Released: January 15, 2015
[Advance publication] Released: September 10, 2014JOURNALS FREE ACCESSDirectly linked linear porphyrin arrays were synthesized and their photophysical properties depending on the length of the arrays were investigated. Ag(I)-promoted oxidative coupling of 5,15-diaryl Zn(II) porphyrins has proven to be effective for preparations of very long meso–meso-linked Zn(II) porphyrin arrays (Zn). A stepwise doubling strategy with strict purification at each doubling step allowed for preparation of gigantic but discrete linear arrays in an unprecedented manner. Large cyclic porphyrin wheels were also synthesized by final meso–meso coupling intramolecular cyclization. Crucial to this success are high reactivity and high regioselectivity of the Ag(I)-promoted oxidative coupling. Equally important are high solubilities of Zn despite their large molecular weights, which arise from their perpendicularly linked structures. Another advantage of this doubling strategy is a large difference in the molecular weights among reactants and products that increases as the reactant array becomes larger, allowing separation of coupling products by preparative GPC-HPLC. As an alternative protocol, Pd-catalyzed Suzuki–Miyaura cross-coupling has been extensively used for synthesis of cyclic porphyrin arrays. This strategy gave novel linear and cyclic porphyrin arrays from β-borylated porphyrins that were prepared by Ir-catalyzed borylation of meso-free porphyrins. As an interesting example, a porphyrin nanotube consisting of four porphyrins doubly bridged by 2,6-pyridinylene spacers was synthesized and revealed to possess a C60-encapsulation capability. Exciton coupling, effective energy hopping, coherent length, and excitation energy transfer of meso–meso-linked linear and cyclic porphyrin arrays are discussed. STM and AFM detections of the large porphyrin arrays are also presented. We believe that these studies expand the range of organic molecules we can manipulate and open a door to a new area of nanoscaled and sub-microscaled functional porphyrin materials.
In this Account, we review our recent research in the synthesis of covalently linked porphyrin arrays. Ag(I)-promoted oxidative coupling of 5,15-diaryl Zn(II) porphyrins and Pd-catalyzed Suzuki–Miyaura cross-coupling have proven to be effective for preparations of discrete large porphyrin arrays. We believe that these studies open a door to a new area of nanoscaled and sub-microscaled functional porphyrin materials. Fullsize ImageView full abstract -
Shiki Yagai2015 Volume 88 Issue 1 Pages 28-58
Published: January 15, 2015
Released: January 15, 2015
[Advance publication] Released: October 07, 2014JOURNALS FREE ACCESSAs details of exciting photonic and electronic properties arising from self-assembled functional dyes and related π-conjugated molecules become clearer, strategies for control of short and long-range chromophore–chromophore orientations, regulation of π–π stacking arrangements, construction of self-organized nano-to-microscale architectures, diversification of materials properties, analysis of self-assembly pathways, and impartment of stimuli-responsive properties, are all becoming important issues in the research area of organic functional materials. This article focuses on the supramolecular assemblies of dyes and related π-conjugated systems whose organization processes are rationally controlled by complementary multiple hydrogen bonding (CMHB) interactions between melamine and barbituric acid/cyanurate functional units. The article includes an overview of the construction principle of such systems, but special attention is focused on the work carried out in the authors’s group (since 2002) using azobenzene, diarylethene, merocyanine, perylene bisimide dyes, and π-conjugated oligomers including oligo(p-phenylenevinylene), oligo(p-phenyleneethynylene), and oligothiophenes. The design principles discussed in this account could open up new avenues to novel functional aspect and application of functional dyes and small-molecular π-conjugated systems.
This article focuses on the supramolecular assemblies of dyes and related π-conjugated systems whose organization processes are rationally controlled by complementary multiple hydrogen-bonding interactions between melamine and barbituric acid/cyanuric acid functional units. Fullsize ImageView full abstract
BCSJ Award Article
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Nobuto Yoshinari, Atsushi Kakuya, Raeeun Lee, Takumi Konno2015 Volume 88 Issue 1 Pages 59-68
Published: January 15, 2015
Released: January 15, 2015
[Advance publication] Released: October 20, 2014JOURNALS FREE ACCESSA unique gold(I)–copper(II) 1D polymeric system, [Cu{Au2(LCn)(pen)2}] (LCn = Ph2P(CH2)nPPh2 (n = 3, 4, and 5); H2pen: penicillamine), which involves three types of helices (single-stranded homochiral helix, single-stranded meso helix, and triple-stranded homochiral helix), is reported. This system was created from linear digold(I) metalloligands, which possess a bis(diphenylphosphino)alkane linker LCn and two-terminal pen coordination arms [Au2(LCn)(pen)2]2−. In this system, the parity (odd vs. even) of the alkyl chain of LCn and the chirality of pen (D vs. L) govern the topology and handedness of the helices, respectively.
Three types of supramolecular helices (single-stranded homochiral helix, single-stranded meso helix, and triple-stranded homochiral helix) were produced from digold(I) metalloligands containing Ph2P(CH2)nPPh2 and penicillaminate (pen) in combination with Cu2+. The helix topology and handedness were controlled by the alkyl chain number (n = 3, 4, and 5) and the chirality of pen (D, L), respectively. Fullsize ImageView full abstract
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Akira Takahashi, Hisashi Tanaka, Nobutsugu Minami, Masato Kurihara, To ...2015 Volume 88 Issue 1 Pages 69-73
Published: January 15, 2015
Released: January 15, 2015
[Advance publication] Released: September 25, 2014JOURNALS RESTRICTED ACCESSWe demonstrated the simultaneous enhancement of two properties of Prussian blue, Cs-adsorption performance and magnetization, using only thermal partial oxidation. The Cs-adsorption performance and magnetic properties of ammonium iron(III) hexacyanoferrate(II) (AFCF) n-hydrate, NH4Fe[Fe(CN)6]1−y·zH2O, were investigated before and after heating at 240 °C for 60 min. Both the distribution coefficient in Cs-adsorption, Kd, and the magnetic susceptibility were enhanced by as much as three times. The adsorption improvement is attributed to a partial structural change accompanying the increase of [Fe(CN)6] vacancies, whereas the change of 50% of Fe into the form of FeOx enhanced the susceptibility. The obtained magnetic adsorbent is applicable for Cs uptake from radioactive Cs wastewater using magnetic separation.View full abstract -
Takeshi Matsumoto, Hirokazu Yano, Masanori Wakizaka, Atsushi Kobayashi ...2015 Volume 88 Issue 1 Pages 74-83
Published: January 15, 2015
Released: January 15, 2015
[Advance publication] Released: October 03, 2014JOURNALS RESTRICTED ACCESSThe reactions of [MoII2(OAc)4] (OAc−: acetato) with catecholato derivatives (R-Cat2−), possessing electron-donating t-Bu groups (3,6-DTBCat2−) or electron-withdrawing Br groups (Br4Cat2−), results in the formation of a mononuclear complex [Na(THF)6][MoV(3,6-DTBCat)3] (1) and a dinuclear complex either [Na6(Br4SQ)2][MoIV2(µ-O)2(Br4Cat)4] or [Na6(Br4Cat)2][MoV2(µ-O)2(Br4Cat)4] (3). Complex 3 has a [Mo(µ-O)2Mo] core as part of a dimer of [O=Mom(Br4Cat)2]n− (m = IV or V, n = 2 or 1) moieties assembled in a head-to-tail arrangement, which has been structurally characterized as the a bis-µ-oxo molybdenum dinuclear complex containing catecholato ligands. The bond distance between the Mo atoms (2.4286(17) Å) strongly suggests that a MoIV=MoIV or MoV–MoV bonding character exists in 3. Differences in the substituent groups on the catecholato ligand affect not only the product formed but also the reactivity of both complexes. Complex 3 shows O-atom abstraction reactivity with dimethyl sulfoxide (DMSO) and forms dimethyl sulfide (DMS). These results support a high oxophilicity of the Mo center in 3.View full abstract -
Daisuke Matsukuma, Hirohmi Watanabe, Aya Fujimoto, Kentaro Uesugi, Aki ...2015 Volume 88 Issue 1 Pages 84-88
Published: January 15, 2015
Released: January 15, 2015
JOURNALS OPEN ACCESSWe have demonstrated that the liquid/solid interfacial structure of liquid marbles is determined by the surface–interface interaction between the encapsulating particles and liquid droplet. X-ray computerized tomography (X-ray CT) confirmed that the decrease of the solid-over-liquid spreading coefficient (SS/L) allowed the particles to be submerged in the liquid. Moreover, the difference in interfacial structure had a strong effect on the dynamic mechanical stability of liquid marbles. Two liquid marbles only merged upon contact when at least one liquid marble had a small SS/L value. X-ray CT observations also revealed that the liquid at the solid/liquid interface did not interdiffuse easily.View full abstract -
Debabrata Jana, Binay K. Ghorai2015 Volume 88 Issue 1 Pages 89-96
Published: January 15, 2015
Released: January 15, 2015
[Advance publication] Released: September 08, 2014JOURNALS RESTRICTED ACCESSThree new 9-arylanthracene-based π-conjugated derivatives with different side substituent (methyl, methoxy, and hexyloxy) were synthesized using Heck coupling/Horner–Emmons reaction in good yields (72–78%) and their photophysical properties investigated. The dependence of the photophysical properties on the side substituent methyl, methoxy, and hexyloxy has been discussed. The absorption maxima of the synthesized compounds in the solution possess similar absorption bands located at 420–423 nm. They are shown to be thermally stable and emit light in sky blue region (ca. 490 nm) in solution. Photoluminescence measurements show a 25–28 nm red shift between solution and powdered states indicated some aggregation in the solid state. The results of cyclic voltammetry measurements of the compounds show good reversibility, indicating that the compounds have good electrochemical stability.View full abstract -
Stephen J. Barigye, Yovani Marrero-Ponce, Jure Zupan, Facundo Pé ...2015 Volume 88 Issue 1 Pages 97-109
Published: January 15, 2015
Released: January 15, 2015
[Advance publication] Released: September 08, 2014JOURNALS RESTRICTED ACCESSThe underlying structural and physicochemical interpretation of the recently defined information indices (denominated as GT-STAF indices) is examined, with the aim of gaining greater insight on the codified chemical information. It is found that these indices are related with molecular symmetry in the context of the defined molecular “fragment” model. Moreover, these indices are sensitive to structural differences, demonstrating gradual changes consistent with modifications in the molecular structure. A principal component analysis reveals that the GT-STAF indices generally codify conformational, physicochemical, and thermodynamic properties of amino acids. A study with aniline derivatives demonstrates that the GT-STAF indices do not directly correlate with the ionization constant (pKa); but rather require multivariate contributions to yield correlations comparable with univariate models for quantum chemical parameters, suggesting that the former codify some other form of electronic information orthogonal to the latter. Finally, an evaluation of atomic contributions to the molecular hydrophobicity in furylethylenes demonstrates that the GT-STAF approach generally approximates to chemical properties quite well.View full abstract -
Junxi Liang, Qiong Su, Yanbin Wang, Zhiyuan Geng2015 Volume 88 Issue 1 Pages 110-116
Published: January 15, 2015
Released: January 15, 2015
[Advance publication] Released: September 10, 2014JOURNALS RESTRICTED ACCESSElectronic structure theory calculations, using MP2 theory and the DFT functionals B3LYP, BHandHLYP, and M05-2X, were performed to characterize the structures, vibrational frequencies, and energies for stationary points on the SN2 reaction of IO− + CH3Cl potential energy surface (PES). The aug-cc-pVDZ basis for C, H, O, and Cl, with an effective core potential (ECP) for iodine, were employed. Single-point CCSD(T) calculations were performed to obtain the complete basis set (CBS) limit for the reaction energies, which were chosen as a benchmark for accuracy of the MP2 and DFT energies. Our results suggest that MP2 and DFT predict the same mechanism on PES, with an exception in the SN2-induced elimination channel. DFT/M05-2X functional is able to give competitive results with respect to the MP2 method for the reactions with SN2 pattern, in which M05-2X results are in good agreement with CCSD(T)/CBS calculations on the whole. In contrast, DFT/BHandHLYP belongs to a better functional for calculations of the SN2-induced elimination channel featured by the H-atom transfer pattern. Moreover, the difference in the MP2 and DFT values for the characters of the reaction of IO− with CH3Cl was further analyzed in detail by the activation strain model and natural bond orbital (NBO) analysis.View full abstract -
Yasuyuki Doi, Masaaki Haneda, Masakuni Ozawa2015 Volume 88 Issue 1 Pages 117-123
Published: January 15, 2015
Released: January 15, 2015
JOURNALS RESTRICTED ACCESSThe effect of CeO2 additive on the catalytic performance of Ba–Y2O3 prepared by coprecipitaion for the direct decomposition of NO was investigated. Although Ba–Y2O3 effectively catalyzed NO decomposition, its activity was clearly increased by addition of CeO2. The optimum CeO2 content was 10 mol %. CO2-TPD measurement revealed that the addition of CeO2 into Ba–Y2O3 caused an increase in the CO2 desorption peak in the temperature range of 473 and 723 K derived from highly dispersed Ba species. The predominant role of CeO2 additive was suspected to effectively create the highly dispersed Ba species as catalytically active sites. Kinetic studies of NO decomposition on Ba–CeO2(10)–Y2O3 suggested that coexisting O2 suppresses the NO decomposition reaction by competitive adsorption. Isotopic transient kinetic analysis suggested a reaction pathway in which the surface NOx adspecies act as reaction intermediates for the formation of N2 in NO decomposition over Ba–CeO2–Y2O3. We concluded that CeO2 additive does not directly participate in the NO decomposition reaction as catalytically active species.View full abstract -
Mohammad Mydul Alam, Kimiko Hashimoto, Chihiro Yamaguchi, Shin-ichi Yu ...2015 Volume 88 Issue 1 Pages 124-126
Published: January 15, 2015
Released: January 15, 2015
[Advance publication] Released: September 25, 2014JOURNALS RESTRICTED ACCESSZinc borate hollow nanospheres with diameter of 30 ± 2 nm have been fabricated by using polymeric micelles of poly(styrene-block-acrylic acid) (PS-b-PAA) as a template. The polymer forms spherical micelles with PS-core and PAA-corona in aqueous solutions, which shows pH-dependent behavior. Zinc borate hollow nanospheres shrink during calcination. FTIR measurements confirm that the template polymer was completely removed during calcination.View full abstract -
Motoi Machida, Shimeng Chensun, Yoshimasa Amano, Fumio Imazeki2015 Volume 88 Issue 1 Pages 127-132
Published: January 15, 2015
Released: January 15, 2015
[Advance publication] Released: September 12, 2014JOURNALS OPEN ACCESSA commercially available activated carbon (AC) was oxidized using 1 M H2SO4 solution containing 2 M (NH4)2S2O8 oxidant with the solution to carbon ratio of 50 cm3 g−1 by changing oxidation period ranging 1 to 10 days at ambient temperatures of 20 or 30 °C to introduce carboxy groups onto the carbon surface to capture Pb(II) ions. Adsorptive removal of Pb(II) ions from aqueous solution was also examined with the oxidized ACs. The Pb(II) ion adsorption progressed via ion exchange with protons of carboxy groups bound to graphite and 2.2 mmol g−1 of Pb(II) could be accommodated at equilibrium pH above 4.0 for ACs oxidized for at least 10 days at 20 °C and 4 days at 30 °C. Decrease in specific surface area and yield and increase in oxygen and hydrogen content in ACs also observed during the (NH4)2S2O8 treatment implied that the oxidation could convert graphite sheets to smaller size by hydrolysis while many carboxy groups would be introduced to the peripherals of the graphite sheets to scavenge Pb(II) ions.View full abstract -
Yoshio Nakahara, Masahiro Hayashizaki, Mitsuru Watanabe, Toshiyuki Tam ...2015 Volume 88 Issue 1 Pages 133-138
Published: January 15, 2015
Released: January 15, 2015
[Advance publication] Released: September 29, 2014JOURNALS RESTRICTED ACCESSUp to date, the development of TiO2 nanoparticles with well-defined morphology, crystallinity, and high solvent dispersibility has been still a big challenge. In this study, monodisperse and spherical SiO2@TiO2 core–shell nanoparticles, whose diameter was 20.7 ± 2.7 nm, with anatase-type crystallinity and high aqueous dispersibility were fabricated by a simple and facile method combing a sol–gel reaction using tetrabutyl orthotitanate as a precursor in the presence of colloidal SiO2 nanoparticles and a very mild crystallization process of the TiO2 layer. Transmission electron microscope measurements showed that the size and shape of the obtained core–shell nanoparticles were considerably uniform. The anatase crystallinity of the TiO2 layer on the particle surface was endowed by heating at 100 °C in the acidic aqueous solution under atmospheric pressure. Also, they maintained high aqueous dispersibility even after the crystallization process. Most importantly, their photocatalytic ability towards methylene blue was comparable to that of commercially available pure TiO2 nanoparticles. The SiO2@TiO2 core–shell nanoparticles developed in this study are highly expected to be membranous materials for very thin TiO2 films due to their high aqueous dispersibility and shape homogeneity.View full abstract -
Souichirou Kawazoe, Takayuki Suzuki, Hirofumi Nakamura, Toshiyuki Sugi ...2015 Volume 88 Issue 1 Pages 139-145
Published: January 15, 2015
Released: January 15, 2015
[Advance publication] Released: September 19, 2014JOURNALS RESTRICTED ACCESSWe describe an alternative route for the synthesis of β3-adrenergic receptor agonist (S)-2-(2-phenylamino-1,3-thiazol-4-yl)-4′-{2-[(2-hydroxy-3-phenoxypropyl)amino]ethyl}acetanilide (1). The key intermediate (S)-1-{[2-(4-aminophenyl)ethyl]amino}-3-phenoxypropan-2-ol monohydrochloride (2) was condensed with 2-(2-phenylamino-1,3-thiazol-4-yl)acetic acid (3) using 1-ethyl-3-(3′-dimethylaminopropyl)carbodiimide hydrochloride (EDCI·HCl) to give 1 as a product of chemoselective amide formation on the aromatic amine moiety. This synthetic route was successfully applied to kilogram-scale preparation without purification via chromatography.View full abstract -
Ryukichi Takagi, Kenji Tanaka, Koumei Yamamoto, Yoshikazu Hiraga, Sato ...2015 Volume 88 Issue 1 Pages 146-148
Published: January 15, 2015
Released: January 15, 2015
[Advance publication] Released: September 19, 2014JOURNALS RESTRICTED ACCESSConstruction of macrocyclic trienes by diene-ene RCM of tetraenes was examined. In the reactions, macrocyclic trienes were obtained as a mixture of two isomers with E,Z-configured 1,3-diene moiety. The formation of two isomers can be understandable by the E–Z isomerization of the initially generated ruthenium–alkenyl carbene intermediate.View full abstract -
Keiji Kinoshita, Takashi Kawakami, Shohei Yoshimura, Toru Saito, Yasut ...2015 Volume 88 Issue 1 Pages 149-161
Published: January 15, 2015
Released: January 15, 2015
[Advance publication] Released: September 22, 2014JOURNALS RESTRICTED ACCESSPhenalenyl, zethrene, and extended zethrene molecules were employed to study the change in electronic properties of graphene surfaces upon exposure to oxygen atmosphere. These hydrocarbons are the smallest systems that can be used to evaluate intermolecular interaction with triplet oxygen molecules. The phenalenyl radical can simulate the radical nature of an edge structure and defect site of graphene sheets. Zethrene and extended zethrene molecules (n = 0, 1, 2, 3, and 4), which possess open-singlet diradical character, are also good models for studying chemisorption phenomena. From the calculated results for phenalenyl, the reaction path from the dissociation limit to the final products was found with chemisorbed structures (SS1 and SS2) and transition states (TS1, TS2, and TS3). Calculated adsorption energies were 7.72 (SS1) and 6.58 (SS2) kcal mol−1. An oxygen molecule can form a contact with phenalenyl radical in a weak chemisorption process, which is endothermic and has very low energy barriers to transition states. For the zethrene series, the diradical character index y, used to describe coupling between two radical spins, was evaluated using the broken symmetry approach. The values were 0.00, 0.01, 0.10, 0.23, and 0.32, for n = 0, 1, 2, 3, and 4, respectively. Although diradical nature was absent in ordinary zethrene, other extended zethrene molecules exhibited diradical character. The radical spin induced in phenalenyl unit A can contribute to the chemisorption of triplet oxygen molecules. The calculated adsorption energy for the first O2 adsorption onto heptazethrene was 5.38 kcal mol−1. Concomitantly, the radical electron on unit B revived and played an important role in the radical activity. The required adsorption energy for the second O2 adsorption became lower at −0.64 kcal mol−1.View full abstract -
Masashi Hatanaka2015 Volume 88 Issue 1 Pages 162-172
Published: January 15, 2015
Released: January 15, 2015
[Advance publication] Released: September 26, 2014JOURNALS RESTRICTED ACCESSStructures of amidinourea–metal complexes have been obscured by subtle tautomerism and crystal waters. To clarify the most stable form of the tautomers, bis(amidinourea)copper(II) anhydride and the alkyl derivatives were synthesized under basic conditions, and the stability of the CuN2O2 chromophore was suggested. From substituent effects of chelations, UV–vis spectra, IR/Raman spectra, and DFT calculations, it was suggested that the bis(amidinourea)copper(II) has a CuN2O2 chromophore, not CuN4 chromophore. The mutual exclusion rule of IR/Raman spectra supported the trans-CuN2O2 chromophore. Systematic calculations on bis(amidinourea)–Cu(II), –Ni(II), –Pd(II), –Zn(II), and –Cd(II) chelates revealed that the robust stability of CuN2O2 chromophores originates from quasi aromaticity in the six-membered chelate rings. cis- or trans-CuN4 stability reported in the early references is suspicious.View full abstract -
Miku Gotou, Tomiyuki Arakawa, Nobuaki Watanabe, Takatoshi Hara, Tatsuy ...2015 Volume 88 Issue 1 Pages 173-175
Published: January 15, 2015
Released: January 15, 2015
[Advance publication] Released: September 24, 2014JOURNALS RESTRICTED ACCESSCu–Mo composites have been expected to be materials of heat sinks in electron devices. We have formed Cu–Mo composites by electrodeposition. Molybdenum content in Cu–Mo composites formed by using Na2MoO4 was larger than that in ones formed by using H3(PMo12O40). Molybdenum content, over 30 wt % in Cu–Mo composites was obtained.View full abstract -
Tzu-Rong Su, Zuo-Jian Liao, Mei-Chin Lu, Yu-Jen Wu, Jui-Hsin Su2015 Volume 88 Issue 1 Pages 176-182
Published: January 15, 2015
Released: January 15, 2015
[Advance publication] Released: September 26, 2014JOURNALS RESTRICTED ACCESSSix new monocarbocyclic sesterterpenoids, luffalides A–F 1–6, together with four known sesterterpenes 7–10, were isolated from a marine sponge Luffariella sp. The structures of compounds 1–6 were elucidated on the basis of spectroscopic data analysis (NMR and CD) and comparison of the spectroscopic data with those of known analogues. Among these new metabolites, compounds 1–5 are rarely found in monocarbocyclic sesterterpenoids possessing a 1-isopropenyl-2-methylcyclopentane ring system. Evaluation of the cytotoxicities showed that compound 10 exhibited significant cytotoxicity against HL-60, MOLT-4 and K-562 cell lines, with IC50 values of 0.54, 0.32, and 0.96 µM, respectively. Moreover, compound 9 also showed significant HL-60 and MOLT-4 inhibitory activity, with IC50 values of 1.87 and 1.13 µM.View full abstract -
Takayuki Hoshi, Junpei Miyake, Masahiro Watanabe, Kenji Miyatake2015 Volume 88 Issue 1 Pages 183-191
Published: January 15, 2015
Released: January 15, 2015
[Advance publication] Released: September 26, 2014JOURNALS RESTRICTED ACCESSA novel series of poly(arylene ether sulfone ketone) multiblock copolymers containing sulfonic acid and bromine groups in the hydrophilic blocks were synthesized and characterized. The copolymers were high molecular weight (Mn = 21–98 kDa, Mw = 234–357 kDa) and provided bendable and transparent membranes by solution casting. The bromine groups caused slight decrease in the proton conductivity at low humidity, however, were effective in improving the mechanical properties as confirmed by dynamic mechanical analyses and tensile tests.View full abstract -
Shinji Toyota, Sayaka Karashima, Tetsuo Iwanaga2015 Volume 88 Issue 1 Pages 192-199
Published: January 15, 2015
Released: January 15, 2015
[Advance publication] Released: October 10, 2014JOURNALS RESTRICTED ACCESSNew extended π-conjugated compounds with two 9,10-bis(phenylethynyl)anthracene units and various linkers were synthesized by one-shot double-elimination reactions and Sonogashira coupling. Their UV–vis and fluorescence spectra were measured to evaluate the effects of the linkers on the π-conjugation. Their photophysical properties are discussed in terms of structures and molecular orbitals obtained by DFT calculations.View full abstract -
Shigeru Sasaki, Takayasu Yamauchi, Masatomi Kanai, Akihiro Ishii, Kimi ...2015 Volume 88 Issue 1 Pages 200-208
Published: January 15, 2015
Released: January 15, 2015
[Advance publication] Released: October 20, 2014JOURNALS RESTRICTED ACCESSBisoxazoline (BOX)-catalyzed asymmetric nucleophilic addition of diethyl zinc to fluorinated alkyl ketones successfully afforded enantioenriched fluorinated alkyl tertiary alcohols. The effect of the size of the substituent on the oxazoline ring on the stereoselectivity of the reaction was investigated. Furthermore, the enantioselectivity could be reversed by altering the BOX bridge structure while retaining the C-4 substituent on the oxazoline ring.View full abstract -
Somaieh Miandari, Majid Jafarian, Mohammad Ghasem Mahjani, Ashraf Heid ...2015 Volume 88 Issue 1 Pages 209-216
Published: January 15, 2015
Released: January 15, 2015
[Advance publication] Released: October 20, 2014JOURNALS RESTRICTED ACCESSElectrochemical deposition and characterization of PbS nanocrystals on Pb electrodes in alkaline solution containing thiourea are carried out by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) methods respectively. The diffusion coefficient of electroactive species (Pb+2) at the synthetic potential −0.36 V/SCE is investigated in different alkaline media. The analysis of PbS crystals using X-ray diffraction (XRD) shows that the average of crystalline size and the lattice constant parameter are approximately 39.04 and 0.5948 nm respectively. Also, the morphology of surface was studied by scanning electron microscope (SEM). This work focuses on EIS extraction of Mott–Schottky plots and calculation of several important parameters including Debye length (LD), carrier density (ND), and flat band potential (Efb) for PbS. The parameters are calculated as 3.40 × 10−8 cm, 8.65 × 1019 cm−3, and 0.035 V/NHE respectively in the dark. The comparison of these values in the dark and under light provides some insights into the charge transfer. The increase in the charge transfer resistance (Rct) in the dark with respect to under illumination and the confirmation of the presence of surface states in the n-type PbS are some of the obtained results.View full abstract -
Naoki Imazu, Tsuyohiko Fujigaya, Naotoshi Nakashima2015 Volume 88 Issue 1 Pages 217-221
Published: January 15, 2015
Released: January 15, 2015
JOURNALS RESTRICTED ACCESSTo fabricate transparent conducting films (TCFs) for electronic devices, both a high conductivity and thermal stability are significant issues due to the need for a high temperature annealing process. In this report, we describe the preparation of a highly transparent (94% transmittance), conductive (surface resistivity: 354 Ω sq−1) and thermally stable double-walled carbon nanotube (DWCNT) film without adding any chemical doping or rinsing. Such film was obtained by a simple dilution and condensation/filtration process (DC/F). The procedure is quite simple, and thus large scalability is easy.View full abstract -
Kazuhiro Nakabayashi, Masaya Yamada, Hideharu Mori2015 Volume 88 Issue 1 Pages 222-226
Published: January 15, 2015
Released: January 15, 2015
[Advance publication] Released: October 28, 2014JOURNALS RESTRICTED ACCESSWe demonstrated the efficient synthesis of naphthalene bisimide (NBI)-based acceptor polymers by palladium-catalyzed direct arylation, which was a more environmentally friendly and efficient method for the synthesis of conjugated polymers compared to conventional cross-coupling reactions. The direct arylation between our designed thiophene-extended NBI-based monomer and 3,4-dimethylthiophene was successfully carried out to yield the desired NBI-based acceptor polymer (PNBI3T-Dr) with a high molecular weight (Mn > 30000, Mw ≈ 90000) in relatively high yield. The optimal direct arylation could afford the NBI-based acceptor polymer with a higher molecular weight in a shorter reaction time than conventional Stille coupling. Furthermore, grazing incidence wide angle X-ray scattering (GIWAXS) analysis revealed that the as-spun PNBI3T-Dr thin film had π–π stacked nanostructure.View full abstract
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