Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 82 , Issue 3
Showing 1-15 articles out of 15 articles from the selected issue
Award Accounts
The Chemical Society of Japan Award for Creative Work for 2005
  • Gan B. Bajracharya, Midori A. Arai, Priti S. Koranne, Takeyuki Suzuki, ...
    2009 Volume 82 Issue 3 Pages 285-302
    Published: March 15, 2009
    Released: March 12, 2009
    JOURNALS FREE ACCESS
    This account focuses our works on the development of chiral spiro ligands bearing N-heterocycles as metal-coordinating units and their applications in the metal-catalyzed asymmetric reactions. The spiro bis(isoxazoline) ligands (SPRIXs), spiro bis(isoxazole) ligands, and spiro (isoxazole–isoxazoline) ligands were readily synthesized through intramolecular double nitrile oxide cycloaddition of the corresponding dioximes as a key step. An unprecedented activation of olefins was displayed by the PdII complexes of these chiral spiro ligands in the enantioselective oxidative cyclizations, for example; the asymmetric tandem cyclization of dialkenyl alcohol via oxy-palladation produced a bicyclic ether in excellent enantioselectivity and enantioselective version of the aminocarbonylation proceeded for the first time. Other hitherto known chiral ligands we examined failed to promote these reactions.
    We have developed a range of novel chiral spiro ligands bearing N-heterocycles as metal-coordinating units. The metal complexes of these ligands displayed unprecedented activation of olefins that allowed us to develop several asymmetric transformations. Fullsize Image
The Chemical Society of Japan Award for Young Chemists for 2006
  • Kei Ohkubo, Shunichi Fukuzumi
    2009 Volume 82 Issue 3 Pages 303-315
    Published: March 15, 2009
    Released: March 12, 2009
    JOURNALS FREE ACCESS
    The natural photosynthetic reaction center utilizes sequential multi-step electron transfer from the excited chromophore to the terminal electron acceptor via electron mediators to attain a long lifetime of the final charge-separated (CS) state. Contrary to natural systems, simple electron donor–acceptor dyads have been developed to attain a long-lived CS state, where the donor and acceptor molecules are linked with a short spacer. In the case of a directly linked zinc chlorin–fullerene dyad, the lifetime of the CS state at −150 °C is as long as 120 s. This value is the longest CS lifetime ever reported for porphyrin-based donor–acceptor linked systems. The use of 9-mesityl-10-methylacridinium ion, which has an extremely long-lived CS state, enables the construction of highly efficient photocatalytic systems such as oxygenation of aromatic compounds and hydrogen evolution.
    Simple electron donor–acceptor dyads with a short spacer have been developed to attain a long-lived charge-separated state. The use of 9-mesityl-10-methylacridinium ion, which has 2 h charge-separation lifetime, enables the construction of highly efficient photocatalytic systems. Fullsize Image
Accounts
  • Osamu Ito, Ken-ichi Yamanaka
    2009 Volume 82 Issue 3 Pages 316-332
    Published: March 15, 2009
    Released: March 12, 2009
    JOURNALS FREE ACCESS
    In the photoinduced intramolecular electron transfer events of donor–bridge–acceptor molecular systems, the bridges play important roles. In the first part of this account, we review charge separation and charge recombination of porphyrin–bridge–fullerene systems, in which the porphyrin acts as a photosensitizing electron donor, whereas the ground state of the C60 moiety acts as an electron acceptor. In such systems, the charge separation usually takes place through the LUMO of the bridges via a super-exchange mechanism and/or a hopping mechanism, depending on their relative LUMO energy levels. On the other hand, the charge recombination of the radical ion pairs usually takes place through the HOMO of the bridges. In the second part, research of charge separation via the excited state of fullerene through the HOMO of the bridges is reviewed. So far, very small damping factors have been reported for π-conjugated bridges such as oligophenyleneacetylenes, oligothiophenes, and oligothiophenevinylenes. On summarizing these results, it is revealed that switching from the super-exchange mechanism in short bridges to hopping mechanism in longer bridges is important to achieve long distance electron transfer through the bridges.
    Roles of molecular wires connecting electron donors such as porphyrin and electron acceptors such as fullerene in photosensitizing electron-transfer processes are summarized in this account. High electron-transferring abilities of the π-conjugated molecular wires are revealed in connection with the MO energy levels and shape of the LUMO and HOMO of these molecular wires. Fullsize Image
BCSJ Award Article
  • Zhong Yu, Takayoshi Kuroda-Sowa, Hiroaki Kume, Takashi Okubo, Masahiko ...
    2009 Volume 82 Issue 3 Pages 333-337
    Published: March 15, 2009
    Released: March 12, 2009
    JOURNALS FREE ACCESS
    The spin-crossover (SCO) complex [Fe(qnal)2]·CH2Cl2 (1), (Hqnal: N-(8′-quinolyl)-2-hydroxy-1-naphthaldimine) with an N4O2 donor set, has been synthesized and characterized. Investigation of magnetic properties shows that the complex exhibits an abrupt and complete spin transition with a 5 K wide thermal hysteresis loop. The X-ray diffraction analysis of complex 1 reveals that the molecules are connected into a quasi one-dimensional chain through extended π–π interactions between aromatic rings of ligands. The effects of metal doping on SCO properties have been investigated in the mixed-metal system [Fe1−xMx(qnal)2]·CH2Cl2 (M = zinc(II) and nickel(II)). The results reveal that metal doping increases the gradual character of spin transition, and no marked differences found between zinc and nickel doping, which suggest the dominant effect of the doping-degree (concentration) rather than metal species on cooperativity. However, the metal doping shows different effects on critical temperature (T1/2), where a more pronounced descending of T1/2 is observed in response to increased Zn-doping than in Ni-doping, indicating the noticeable consequence of internal pressure due to the different radii of doping metal ions.
    Metal-doping experiments in a spin-crossover system [Fe1−xMx(qnal)2]·CH2Cl2 with M = zinc(II) or nickel(II) reveal that the decrease of cooperativity in the spin transition occurred in both cases while only zinc(II) doping induces the decrease of critical temperature T1/2. Fullsize Image
  • Yoshitake Sakae, Toshiaki Matsubara, Misako Aida, Hidemasa Kondo, Kazu ...
    2009 Volume 82 Issue 3 Pages 338-346
    Published: March 15, 2009
    Released: March 12, 2009
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    A cutinase-like enzyme (CLE), which is purified experimentally from the yeast Cryptococcus sp. strain S-2, has been recently found to degrade biodegradable plastics very efficiently. In this study, we theoretically examine the mechanism of hydrolysis of biodegradable plastics by the CLE by means of the ONIOM method. We optimize all the intermediates and the transition states involved in the considered enzymatic reaction and determine the energy surface of the entire catalytic cycle. The calculations show that the amino acid residues inside the pocket of the active site, Thr17 and Gln86, which stabilize the tetrahedral intermediates, and Gly115 in addition to Ser85, His180, and Asp165, which compose the catalytic triad, significantly contribute to the catalytic reaction. This is similar to the case of serine protease reported to date. Moreover, we have newly found that the energy barrier of the catalytic cycle is significantly lowered by the electronic effect of the OH group in the side-chain of Thr17 and bound water. The calculated potential energy surface of the reaction shows that the cleavage of the ester bond is a rate-determining step.
  • Takashi Kosone, Yusuke Suzuki, Chikahide Kanadani, Toshiaki Saito, Tak ...
    2009 Volume 82 Issue 3 Pages 347-351
    Published: March 15, 2009
    Released: March 12, 2009
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    New novel 2D network bimetallic MnIIAgI coordination compounds {MnII(L)2[AgI(CN)2]2}n (L = 3-methylpyridine (1) or 4-methylpyridine (2)) were synthesized and characterized by using single-crystal X-ray analysis and magnetic measurements. MnII ion in both complexes has MnN6 coordination with octahedral geometries, which are linked by a [AgI(CN)2] unit at the equatorial plane to form a polymeric 2D sheet architecture. The two pyridine rings coordinate at the axial positions. However, coordination polymers for 1 and 2 are structural isomers. The structure of 1 comprises a parallel 2D array and the layers interact by pairs defining bilayers with strong binuclear argentophilic interaction, while 2 comprises a double interpenetration structure with 1D-chain weak argentophilic interaction. Furthermore, intermolecular C···C contacts in these complexes are significantly smaller than the sum of the van der Waals radius. Variable-temperature (2–300 K) magnetic susceptibility measurements of both the compounds have been performed to understand the possibility of spin transition in 1 and 2. However, the susceptibility data of 1 and 2 indicate the existence of high-spin (HS) state manganese(II) throughout the temperature range.
  • Etsuko Tomiyama, Kazuaki Tomono, Daisuke Hashizume, Tatsuo Wada, Kazuo ...
    2009 Volume 82 Issue 3 Pages 352-357
    Published: March 15, 2009
    Released: March 12, 2009
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    A series of [Ni(dmit)2] (1) (dmit = 2-thioxo-1,3-dithiole-4,5-dithiolato) complex salts with 3,4-dimethylthiazolium (2), 2,3,4-trimethylthiazolium (3), and 3,4,5-trimethylthiazolium (4) cations (I, II, and III, respectively) were synthesized and characterized by single-crystal X-ray analysis and conductivity. The molecular structures of 1 were the same in all three complex salts. In the structure of I, the anions were arranged in hexagonal structures. Neighboring hexagons formed honeycomb sheet structures as the result of S···S interactions in the (001) plane. The sheets of the honeycomb structures were arranged along the c axis with translational symmetries that form columnar honeycomb channels along the &bcsj_2009_352; direction. In the structures of II and III, honeycomb sheet structures were formed as in I. But in contrast to I, the relative position of the stacked sheets in II and III was slightly dislocated, forming zig-zag channels instead. The IR spectra of I, II, and III show that the C=C stretching band is slightly red-shifted to 1337–1339 from 1350 cm−1 for [Ni(dmit)2], caused by the partial oxidation of the anion. The measured values of the electrical conductivities were 0.20, 0.094, and 0.16 S cm−1 for I, II, and III, respectively. These high conductivities may be ascribed to the partially oxidation of the anion. The S···S interactions regulate the honeycomb sheet structure of the crystal and should work as conduction pathways effectively.
  • Machiko Arakawa-Itoh, Kana Tokuman, Yukie Mori, Takashi Kajiwara, Masa ...
    2009 Volume 82 Issue 3 Pages 358-363
    Published: March 15, 2009
    Released: March 12, 2009
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    A reaction of copper(II) perchlorate with a sterically hindered diamine, 1,2-dipiperidinoethane (dipe), yields two dinuclear complexes: di-μ-hydroxo dinuclear complex [{Cu(ClO4)(dipe)(μ-OH)}2] (1) and di-μ-alkoxo dinuclear complex [{Cu(ClO4)(dipe-O)}2] (2) (dipe-O is 1-(2-piperidinoethyl)piperidin-3-olate which was newly obtained in this work). The structures of complexes 1 and 2 were confirmed by X-ray crystallography. Complex 2 is meso form containing (R)- and (S)-dipe-O. Dipe-O acts as a tridentate ligand with an N,N,O-donor set and bridges two copper(II) ions through the oxygen atom. The oxygen atom is incorporated into dipe from atmospheric molecular oxygen during the reaction of dipe with copper ion. The temperature dependences of χmT values were different between 1 and 2 depending on the bridging structures. Complex 1 shows ferromagnetic interaction and the value of 2J = 117 cm−1 is in agreement with that predicted from the ∠Cu–O–Cu bridging angle of 96.9°. Complex 2, the bridging angle of which is 100.59°, shows a strong antiferromagnetic interaction (−2J > 400 cm−1). The singlet–triplet energy gap for complex 2 was estimated from DFT calculation.
  • Miki Kometani, Kohki Ihara, Rumi Kimura, Hideki Kinoshita
    2009 Volume 82 Issue 3 Pages 364-380
    Published: March 15, 2009
    Released: March 12, 2009
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    Reaction of methyl N-Boc-N-phenoxycarbonylglycinate with various aldehydes afforded the corresponding cis-4,5-oxazolidinone derivatives, which were effectively converted to (E)-α,β-didehydroamino acids by means of a base. Furthermore, N-deprotection of the oxazolidinone derivatives and subsequent coupling reaction with Boc-amino acid furnished the corresponding dipeptides, which were transformed to dipeptide containing α,β-didehydroamino acid with high E selectivity.
  • Kiichi Kuroda, Yuji Maruyama, Yujiro Hayashi, Teruaki Mukaiyama
    2009 Volume 82 Issue 3 Pages 381-392
    Published: March 15, 2009
    Released: March 12, 2009
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    Preparation of alkyl aryl sulfides from alcohols and arenethiols such as 2-sulfanyl-1,3-benzothiazole (BtzSH) is described by a new type of oxidation–reduction condensation using phenyl diphenylphosphinite (PhOPPh2) and benzoquinone derivatives or azide compounds. This reaction proceeds under mild and neutral conditions and is applicable to the thioetherification of various alcohols in which the chiral secondary and tertiary alcohols are converted into the corresponding chiral sulfides with almost complete inversion of configuration.
  • Junichi Imoto, Sayuri Hayashi, Koji Hirano, Hideki Yorimitsu, Koichiro ...
    2009 Volume 82 Issue 3 Pages 393-400
    Published: March 15, 2009
    Released: March 12, 2009
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    A method for the synthesis of 2-aryl-1,3-alkadienes has been developed. Treatment of aryl bromides with 3,4-alkadien-1-ols in the presence of a palladium catalyst results in 1-methylene-2-propenyl group transfer to aryl bromides. Taking advantage of palladium-mediated retro-allylation as an sp3C–sp3C bond cleavage reaction, one can regard 3,4-alkadien-1-ols as 1-methylene-2-propenyl metal equivalents that are easy to prepare and are not sensitive to air and moisture. In the event that the Diels–Alder dimerization of the product during the 1-methylene-2-propenylation reaction is problematic, addition of N-methylpyrrole to the reaction mixture can efficiently suppress the dimerization. The reactions of aryl bromides with 2-substituted 3,4-alkadien-1-ols yield the corresponding (E)-2-aryl-1,3-alkadienes stereoselectively.
  • Hiroshi Hashiguchi, Kazuhiko Maeda, Ryu Abe, Akio Ishikawa, Jun Kubota ...
    2009 Volume 82 Issue 3 Pages 401-407
    Published: March 15, 2009
    Released: March 12, 2009
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    The photoelectrochemical properties of a GaN:ZnO solid solution coated as an electrode on conductive glass are investigated through measurement of voltammograms and current–time curves. The highest photocurrent was achieved by a GaN:ZnO sample with relatively high zinc concentration (Zn/Ga = 0.42) and small particle size, presumably due to more efficient electron transfer through the porous electrode. The electrode exhibits anodic photocurrent under visible light, indicating functionality as an n-type semiconductor electrode. The estimated band-gap position of GaN:ZnO is located at satisfactory potential for water splitting. The bottom of the conduction band is similar to that for GaN, while the top of the valence band is substantially higher than that of either GaN or ZnO. The evolution of H2 and O2 is confirmed during photoelectrolysis at +0.5 V vs. Ag/AgCl. The efficiency of photoelectrolysis is found to decrease with irradiation time due to degradation of the electrode.
  • Makoto Ogawa, Takayuki Matsutomo, Tomohiko Okada
    2009 Volume 82 Issue 3 Pages 408-412
    Published: March 15, 2009
    Released: March 12, 2009
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    Iron-containing hectorite-like layered silicate was synthesized by the reaction of LiF, Mg(OH)2, colloidal silica, and FeCl3 in aqueous suspension at 100 °C for 2 days. From X-ray diffraction and infrared spectroscopic analysis, the formation of hectorite-like layered silicate was shown. Dimethyldioctadecylammonium and 1,1′-dimethyl-4,4′-bipyridinium (methyl viologen) ions were intercalated by cation-exchange reactions into the interlayer space of the iron-containing silicate. The intercalated amounts of both cationic species were larger compared to iron-free layered silicate, showing increase in the layer charge density of the silicate by the incorporation of iron(III). The increase in the layer charge was thought to be derived from isomorphous substitution of silicon(IV) by iron(III) in the silicate layer. The structural iron(III) was reduced to iron(II) by reaction with sodium dithionite, which was shown by a color-change (yellow to green) and the increase in the intercalated amounts of dimethyldioctadecylammonium and 1,1′-dimethyl-4,4′-bipyridinium ions.
  • Kohei Shiramizu, Yosuke Harada, Takakazu Yamamoto
    2009 Volume 82 Issue 3 Pages 413-415
    Published: March 15, 2009
    Released: March 12, 2009
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    Reactions of 2-amino-3,5-dibromopyridine with sultones gave 3,5-dibromopyridines with –NH(CH2)mSO3Na (m = 3 and 4) groups at the 2-position of pyridine. The obtained compound served as a starting material for polypyridine with –NH(CH2)mSO3H side chains.
  • Setsuko Yamane, Ayae Sugawara, Yoshihiro Sasaki, Kazunari Akiyoshi
    2009 Volume 82 Issue 3 Pages 416-418
    Published: March 15, 2009
    Released: March 12, 2009
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    Self-assembled polysaccharide nanogels with negative or positive charges were used as templates for mineralization of calcium phosphate for potential biomedical application. The formation of stable and negatively- or positively-charged amorphous calcium phosphate nanoparticles was confirmed by transmission electron microscopy, energy-dispersive X-ray spectroscopy, and ζ-potential measurements.
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