Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 78 , Issue 7
Showing 1-29 articles out of 29 articles from the selected issue
Award Accounts
The Chemical Society of Japan Award for Young Chemists for 2003
  • Hideki Fujiwara, Hayao Kobayashi
    2005 Volume 78 Issue 7 Pages 1181-1196
    Published: 2005
    Released: July 01, 2005
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    The first antiferromagnetic organic superconductor, κ-(BETS)2FeBr4 [BETS = bis(ethylenedithio)tetraselenafulvalene], was developed in the search for novel magnetic molecular conductors. This salt shows successive antiferromagnetic and superconducting transitions at TN = 2.5 K and Tc = 1.1 K, respectively, at ambient pressure. Specific heat measurements and anisotropic behavior of intraplanar conducting properties under applied magnetic fields prove the coexistence of the antiferromagnetic ordering and superconductivity below Tc. The combination of metamagnetism of the magnetic layer and superconductivity of the conduction layer, which makes this salt a dual-functional system, yields two characteristic magnetic field-induced superconducting states around 1.6 and 12.5 T in terms of the Jaccarino–Peter compensation effect. Systematic studies on both the chemical pressure effect by a halogen exchange in the alloy system κ-(BETS)2FeBrxCl4−x and the physical pressure effect by an application of real pressures in κ-(BETS)2FeBr4 were performed to discuss the π–d interaction in the κ-(BETS)2FeBr4 system.
Accounts
  • Yoshihiro Ohmiya, Satoshi Kojima, Mitsuhiro Nakamura, Haruki Niwa
    2005 Volume 78 Issue 7 Pages 1197-1205
    Published: 2005
    Released: July 01, 2005
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    Latia neritoides is a small limpet-like snail that produces a bright green bioluminescence; it is found only in New Zealand streams. The light-emitting system is unique. Although Latia bioluminescence has been studied since 1880, its mechanism is unclear. Shimomura and Johnson clarified the elements of the mechanism, including the structures of luciferin and luciferase, in 1968. However, neither the emitter nor the mechanism of the excited state of luciferin has been determined. We studied molecular mechanisms to clarify the characteristics of luciferin and luciferase and to produce a new application for this system.
BCSJ Award Article
  • Seiji Suga, Yamato Tsutsui, Aiichiro Nagaki, Jun-ichi Yoshida
    2005 Volume 78 Issue 7 Pages 1206-1217
    Published: 2005
    Released: July 01, 2005
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    N-Acyliminium ion pools, which are generated from α-silyl carbamates, were found to react with a variety of alkenes and alkynes to give the corresponding cycloadducts. The reaction with styrene derivatives gave rise to the formation of a significant amount of polymeric products. The use of micromixing, however, resulted in a significant increase in the yield of the cycloadduct at the expense of the polymer. Mechanistic studies indicated that a concerted mechanism seems to be most likely for alkyl-substituted alkenes, whereas a stepwise mechanism seems to be reasonable for aryl-substituted alkenes.
Articles
  • Raju, Zaheer Khan
    2005 Volume 78 Issue 7 Pages 1218-1222
    Published: 2005
    Released: July 01, 2005
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    A conventional spectrophotometric technique was used to study the oxidation of SDS by permanganate in a perchloric acid medium. It was observed that the reaction proceeded in two stages (fast first stage followed by a relatively slow second stage). Plots of log(absorbance) versus time deviate from linearity. The kinetic and spectroscopic data are consistent with the formation of soluble colloidal MnO2. The first-order kinetics with respect to [SDS] at low concentrations shifted to second-order at higher concentrations. The kinetics of oxidation is first-order with respect to both [MnO4] and [HClO4]. The oxidation rate was decreased by the addition of P2O74− and Mn(II) ions. Second-step oxidation is not a true path for the oxidation of the Mn(IV)–SDS reaction. In the presence of Mn(II) (a reaction product), the MnO4 oxidation of SDS becomes more complicated, and an exact dependence on [Mn(II)] can not be estimated. Different activation parameters have been evaluated. Mechanisms consistent with the kinetic data have been proposed and discussed. The –O–SO3 group is responsible for the oxidative degradation of SDS by MnO4.
  • Kayako Hori, Yuko Iwai, Megumi Yano, Reiko Orihara-Furukawa, Yasunori ...
    2005 Volume 78 Issue 7 Pages 1223-1229
    Published: 2005
    Released: July 01, 2005
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    Temperature-dependent X-ray diffraction (XRD) studies using synchrotron radiation and Raman spectral studies in the range of 40–850 cm−1 have been carried out for crystalline polymorphs of the title compounds in order to elucidate the phase relations of the polymorphs. Transition processes between metastable phases have been confirmed with structural evidence: square-plate (SP) crystal to needle (N) crystal for 7OCB and parallelpiped plate (PP) crystal to needle (N) crystal for 8OCB; these processes were previously proposed based on the results of differential scanning calorimetry. XRD study shows that a fourth phase of 7OCB, which appears during the stabilization process and hence is referred to as an intermediate phase, is a slightly but definitely different crystalline phase from the most stable phase. SP of 7OCB stabilizes in two steps: first to the intermediate phase, which then rearranges to the most stable phase at the melting point of the intermediate phase just below the melting point of the most stable phase or on keeping at RT for several months or longer. Some structural features of the most stable phases of 7OCB and 8OCB are discussed based on the unit cell parameters derived from the powder XRD results.
  • Nobuaki Kanamaru
    2005 Volume 78 Issue 7 Pages 1230-1240
    Published: 2005
    Released: July 01, 2005
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    A theory of the molecular symmetry group (MSG) is presented to describe the spectroscopy of molecules that consist of methyl (top) and planar (frame) groups and belong to the G12 MSG. This was done in a form of Fourier-series expansion on the torsional angle of the methyl group concerning its two kinds of coupling terms, by choosing three kinds of systems in the title: (1) A morphing technique to describe the vibronic coupling is applied to interpret the torsionally induced S1 ← S0 absorption spectra of toluene (as partially described in a recent Letter). (2) The torsion–vibration coupling term in the top (through its interaction with the frame) was confirmed to split the degenerate e′ levels of either vibrational or torsional modes into either a1″ + a2″ levels/modes or a1′ + a2′ levels, respectively. The latter was made with the interpretation of either broad IR absorption spectra of nitromethane or peculiar low-frequency bands in the electronic spectra of 5-methyltropolone, respectively.
  • Ryuichi Ikeda, Satoshi Takahashi, Taka-aki Nihei, Hideta Ishihara, Hir ...
    2005 Volume 78 Issue 7 Pages 1241-1245
    Published: 2005
    Released: July 01, 2005
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    35Cl NQR and 1H NMR relaxation times (T1Q, T1H) were measured in a hydrogen-bonded (chloranilic acid)-(1,3-diazine) 1:2 molecular complex in a temperature range of ca. 100–300 K. NQR frequencies observed were explained by the monovalent (1−) ionic structure of chloranilic acid, implying partial H-transfer to diazine molecules. This H-transfer was shown to be dynamic by observing a single T1H minimum at ca. 120 K. Two new relaxation processes observed by NQR in high-temperature range, but undetected by NMR, were shown to be H-transfer motions between differently charged states of chloranilic acid molecules.
  • Liu Fengyi, Zeng Xiaoqing, Sun Qiao, Meng Lingpeng, Zheng Shijun, Ai X ...
    2005 Volume 78 Issue 7 Pages 1246-1250
    Published: 2005
    Released: July 01, 2005
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    Oxalyl diazide O2C2(N3)2 has been generated in the heterogeneous reaction of (COCl)2 vapor with AgN3 at room temperature. Evidence for the formation of O2C2(N3)2 is based on on-line photoelectron spectroscopy (PES) characterization combined with the density functional B3LYP and outer valence Green’s function (OVGF) calculations. The good agreement between the experimental spectra and theoretical calculation shows that O2C2(N3)2 has adiabatic ionization energy of 10.11 eV. Our results also suggest that O2C2(N3)2 has high conformational flexibilities and that the planar conformers are energy-favorable in gas phase.
  • Akio Katsuki, Ichiro Uechi, Yoshifumi Tanimoto
    2005 Volume 78 Issue 7 Pages 1251-1255
    Published: 2005
    Released: July 01, 2005
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    A liquid/solid redox reaction between silver ion and zinc metal was investigated under a vertical and inhomogeneous magnetic field. 2-Dimensional silver dendrites produced via the reaction were drastically affected by the magnetic field. Oriented and tilted dendrites were observed under the magnetic field. A similar phenomenon was observed at a silver ion–copper metal system under a horizontal and homogeneous magnetic field. The mechanism of the phenomenon is discussed in detail.
  • Isao Kanesaka, Yuichi Hayashi, Yoshiyuki Morioka
    2005 Volume 78 Issue 7 Pages 1256-1258
    Published: 2005
    Released: July 01, 2005
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    In spinel (MgAl2O4), the strongest infrared band at 485 cm−1 shows less LO–TO splitting than the medium band at 670 cm−1. This unexpected relationship is explained in terms of the vibrational coupling of these TO modes. A new manner for evaluating the LO mode is proposed.
  • Katsuya Teshima, Hitoshi Kondo, Shuji Oishi
    2005 Volume 78 Issue 7 Pages 1259-1262
    Published: 2005
    Released: July 01, 2005
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    The growth of hexagonal bipyramidal ruby crystals by the flux evaporation method in the Li2O–MoO3 flux system has been reported. Ruby crystals were grown by heating a mixture of a solute (Al2O3 + 0.5 wt % Cr2O3) and a flux (Li2O–MoO3) at 1050, 1100, or 1200 °C, followed by holding the solution at these temperatures for 5 h. The crystal size was dependent on the evaporation loss of the flux. The evaporation loss of the flux gradually decreased with increasing amount of Li2O added to MoO3, and increased with the holding temperature. The obtained ruby crystals had lengths of up to 2.6 mm and widths of up to 2.1 mm, and had a transparent-red color. Their form was a bipyramid, bounded by well-developed faces. The most suitable flux composition for high-quality and large ruby crystal growth was found to be 2 mol % Li2O–98 mol % MoO3.
  • Masaaki Tabata, Ahsan Habib, Keiichi Watanabe
    2005 Volume 78 Issue 7 Pages 1263-1269
    Published: 2005
    Released: July 01, 2005
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    DNA (pBluescript plasmid, 2.96 kbp) cleavage by Good’s buffers, which are extensively used in laboratories of chemistry, biochemistry, or biology, was studied by gel electrophoresis, CD spectra, ESR spectra, and CV in the presence of Au(III). Incubation of plasmid DNA with Good’s buffers and Au(III) resulted in DNA cleavage. DNA cleavage occurred due to the formation of nitrogen-centered cationic free radicals from the Good’s buffers in the presence of Au(III). The formation of the nitrogen-centered free radicals was confirmed by ESR spectroscopy. Gel electrophoresis results indicated that Form I and Form II were converted into Form III and a DNA fragment. The molecular weight of the DNA fragment was estimated ca. 1.47 kbp by DNA marker gel electrophoresis. ESR spectra were not observed from the Good’s buffers in the presence of other metal ions, such as Mn(II), Fe(III), Co(II), Ni(II), Zn(II), Pd(II), Cd(II), Hg(II), and Pb(II), resulting in no DNA cleavage. Gel electrophoresis results indicated a partial DNA cleavage during the incubation of DNA in the presence of Good’s buffers and Au(III). This is because the DNA cleavage reaction stopped at 15 min, since the radical lifetime is ca. 15 min. The intensities of the CD spectra at 270 nm decreased with time by 15 min upon the addition of Au(III), and a constant CD spectrum was observed after 15 min. Further addition of Au(III) showed an alternation of the CD spectra from positive ellipticity to negative ellipticity at 270 nm, suggesting significant DNA cleavage. The mechanism of DNA cleavage is discussed based on the gel electrophoresis, ESR, CD, and CV results.
  • Taka-aki Okamura, Keiko Sakauye, Mototsugu Doi, Hitoshi Yamamoto, Nori ...
    2005 Volume 78 Issue 7 Pages 1270-1278
    Published: 2005
    Released: July 01, 2005
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    A series of crystal structures of acylaminoferrocenes, [(C5H5)Fe(C5H4NHCOR)] (R = CH3 (1), CH2CH3 (2), t-Bu (3), and CF3 (4)) revealed an unusually delicate dependence of the alkyl substituent structure on electron transfer through NH···O=C bonding and π-conjugation. The presence of strong intermolecular NH···O=C hydrogen bonds in the crystal was established by X-ray, IR, and CRAMPS. Compounds 1 and 2 are without steric or electrostatic hindrance, and both exhibit continuous and strong hydrogen-bond chains, or an effective π-electrons system. However, the hydrogen-bond chains in 3 and 4 are weak, or broken, by the bulkiness of t-Bu or the electrostatic repulsion of CF3. Solid-state cyclic voltammograms of 14 have revealed the electrochemical processes, which are critically dependent on the array and the strength of the hydrogen bonds. Although both 3 and 4 show typical reversible cyclic voltammograms, 1 and 2 exhibit irreversible redox behaviors and remarkably large current values, which indicate the presence of an effective electron transfer through the continuous hydrogen-bond chains.
  • Kyoichi Tanimura, Ryoko Kitashima, Nicolas Bréfuel, Masaaki Nak ...
    2005 Volume 78 Issue 7 Pages 1279-1282
    Published: 2005
    Released: July 01, 2005
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    A spin crossover (SC) FeIII complex, [FeIII(4-NH2py)L]BPh4, was synthesized and characterized, where 4-NH2py = 4-aminopyridine, H2L = pentadentate N3O2 Schiff-base ligand of the 2:1 condensation product of 3-methoxysalicylaldehyde and bis(3-aminopropyl)methylamine, and BPh4 = tetraphenylborate. Cryomagnetic susceptibility measurements revealed a steep spin transition between FeIII low-spin (S = 1/2) and high-spin (S = 5/2) states at T1/2 = 120 K, but showed no hysteresis. Crystal-structural analyses were performed at 293 and 90 K in order to investigate the origin of the steep spin crossover, and to determine the structures of the high-spin and low-spin states. The crystal structure consisted of a one-dimensional chain constructed by hydrogen bonds between the amino group of 4-NH2py of a molecule and the methoxy group of the adjacent molecule.
  • Menghe BaiYin, Ling Ye, Yonglin An, Xin Liu, Cuiying Jia, Guiling Ning
    2005 Volume 78 Issue 7 Pages 1283-1284
    Published: 2005
    Released: July 01, 2005
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    A novel framework, (NH4)2Ag6Sn3S10, was synthesized solvothermally and characterized by single-crystal X-ray diffraction. The framework comprises silver-rich cationic layers, [Ag6SnS4]2+, pillared by [SnS3]2− zigzag chains formed by vertex-sharing SnS4 tetrahedra; NH4+ ions are located in 1D channels.
  • Yuki Matsunaga, Kiyoshi Fujisawa, Naoko Ibi, Nagina Amir, Yoshitaro Mi ...
    2005 Volume 78 Issue 7 Pages 1285-1287
    Published: 2005
    Released: July 01, 2005
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    New homoleptic aliphatic thiolato complexes with Zn(II), (Et4N)[Zn(SAd)3] (1) (HSAd = 1-adamantanethiol), and (Et4N)2[{Zn(ScHex)2}2(μ-ScHex)2] (2) (HScHex = 1-cyclohexanethiol), have a novel three-coordinate geometry for monomeric 1 and a tetrahedral geometry for dimeric 2, respectively. The complexes have been fully characterized by far-IR, Raman, and UV–vis absorption spectroscopy.
  • Makoto Tanabe, Masumi Itazaki, Osamu Kitami, Yasushi Nishihara, Kohtar ...
    2005 Volume 78 Issue 7 Pages 1288-1290
    Published: 2005
    Released: July 01, 2005
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    Reactions of PPh2H with [M(PCy3)2] (M = Pt, Pd) produce the dinuclear complexes with bridging PPh2 ligands of these metals, [{Pt(H)(PCy3)}2(μ-PPh2)2] and [{Pd(PCy3)}2(μ-PPh2)2], respectively.
  • Ayumi Kashiwada, Yohei Nakamura, Kiyomi Matsuda
    2005 Volume 78 Issue 7 Pages 1291-1295
    Published: 2005
    Released: July 01, 2005
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    To construct polypeptides that undergo a hetero-block α-helical coiled coil structure change due to metal ion-induced self-assembly formation, we designed two kinds of 18-residue polypeptides, Pep3 and Pep4, each with a metal binding site. Pep3 and Pep4 were designed based on the sequence of the isoleucine zipper polypeptide forming the triple-stranded α-helical coiled coils. While Pep3 and Pep4 are too short to form a parallel triple stranded α-helical coiled coil individually, they form the hetero-block α-helical coiled coil structure, (Pep3)3–Ni2+–(Pep4)3 in the presence of the Ni2+ ions. Circular dichroism spectroscopy and size-exclusion gel-filtration chromatography analyses revealed the formation of the (Pep3)3–Mn+–(Pep4)3 hetero-block α-helical coiled coil complex.
  • Shamil Latypov, Mohammed A. Fakhfakh, Jean-Christophe Jullian, Xavier ...
    2005 Volume 78 Issue 7 Pages 1296-1301
    Published: 2005
    Released: July 01, 2005
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    Experimental data from proton NMR studies combined with ab initio calculations (energy and GIAO chemical shifts) indicated that quinoline(s), in solution, exist in equilibrium as a series of stacks (dimers or n-mers) that are slightly different in mutual orientation. The self-association constant depends dramatically on the concentration of the substrate: at low concentration, recognition occurs and dimerization, with association constants that are approximately 200 times larger than for higher n-mers at higher concentration, was observed.
  • Ryo Hanai, Xun Gong, Motoo Tori, Satomi Kondo, Kanako Otose, Yasuko Ok ...
    2005 Volume 78 Issue 7 Pages 1302-1308
    Published: 2005
    Released: July 01, 2005
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    Three Ligularia species (L. tongolensis, L. cymbulifera, and L. atroviolacea) were examined with respect to the chemical composition and nucleotide sequence. Furanoeremophilanes were found to be produced in the root of all samples of the three species collected in northwest Yunnan and southwest Sichuan. Eight furanoeremophilanes were identified, two of which were new. Most of the identified furanoeremophilanes were oxygenated at 3, 6, and 15-positions. The nucleotide sequence of the atpB-rbcL intergenic region was found to be essentially the same in the three species. These similarities imply that the three Ligularia species, all belonging to the section Corymbosae, are close to one another. The intra-specific diversity in the two widely distributed species in the Hengduan Mountains area, L. tongolensis and L. cymbulifera, were in contrast. Four out of 19 L. tongolensis samples contained a strongly Ehrlich-positive compound besides a number of positive compounds, and five variants of the atpB-rbcL sequence were found in these samples. In contrast, no variation was observed in 13 L. cymbulifera samples with respect to the furanoeremophilane composition or the atpB-rbcL sequence. The lack of diversity in L. cymbulifera probably resulted from the uniformity of its habitat.
  • Yasuyuki Ogawa, Kiichi Kuroda, Teruaki Mukaiyama
    2005 Volume 78 Issue 7 Pages 1309-1333
    Published: 2005
    Released: July 01, 2005
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    The samarium(II) iodide-mediated stereoselective aldol reactions of acylaziridines with aldehydes are described. β-Amino–β′-hydroxy ketones were synthesized in high yields by the aldol reaction of aldehydes with samarium enolates generated by aziridine-fragmentation of aziridinyl ketones with two moles of samarium(II) iodide. By the choice of an appropriate nitrogen protecting group, depending on the substituent at C-3 position of aziridinyl ketone, anti,anti-β-amino–β′-hydroxy ketones were diastereoselectively obtained among the four possible diastereomers. Further, enantiomerically pure anti,anti-β-amino–β′-hydroxy ketones were successfully obtained by this aldol reaction when chiral aziridinyl ketones were used. In addition, δ-amino–β′-hydroxy–β,γ-unsaturated esters were also synthesized in high yields by the aldol reaction of aldehydes with samarium enolates generated by aziridine-fragmentation and olefin-migration of γ,δ-aziridinyl–α,β-unsaturated esters using two moles of samarium(II) iodide. This aldol reaction proceeded with complete α-regioselectivity and formed (E)-olefin selectively. By introducing chiral oxazolidin-2-one auxiliary to γ,δ-aziridinyl–α,β-unsaturated carbonyl system, this reaction was extended successfully to the asymmetric reaction and enantiomerically pure syn-δ-amino–β′-hydroxy-β,γ-unsaturated esters were obtained in high yields.
  • Hayato Tsuji, Yuki Shibano, Tohru Takahashi, Makoto Kumada, Kohei Tama ...
    2005 Volume 78 Issue 7 Pages 1334-1344
    Published: 2005
    Released: July 01, 2005
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    Several configurationally constrained cis- and trans-1,2-diaryl-1,2-dimethyl-1,2-disilacyclohexanes (3ae) have been synthesized in order to measure their photophysical properties, such as UV absorption, magnetic circular dichroism (MCD), and photoluminescence. As has been well established, the UV absorption maximum (1La band) occurs at 230–270 nm, due to the effective σ–π conjugation between the aryl groups and the disilane moiety. The absorption maximum wavelength of the trans isomer is slightly longer than that of the cis isomer for all the diaryldisilanes employed in the present study. Although the MCD spectra of the cis- and trans-1,2-diphenyl-1,2-dimethyl-1,2-disilacyclohexanes (3a) show only a slight configuration dependence, this method is helpful to detect a weak 1Lb band. The disilanes 3a and 5a show a charge-transfer (CT) emission band. The quantum yields are dependent on the disilane configuration and the solvent polarity; the order of the quantum yield is cis-3a < 5a < trans-3a in 3-methylpentane, while the order is 5a < cis-3a < trans-3a in acetonitrile. These results demonstrate that the conformation constraint is effective for controlling the photophysical properties of the diaryldisilanes.
  • Hiroki Shimogawa, Toshiaki Teruya, Kiyotake Suenaga, Hideo Kigoshi
    2005 Volume 78 Issue 7 Pages 1345-1347
    Published: 2005
    Released: July 01, 2005
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    New 13-epi-neoverrucosane-type diterpenes 1 and 2 were isolated from the marine sponge Axinyssa tethyoides. Their structures were elucidated by 2D-NMR spectroscopy, the modified Mosher’s method, and fluorescent X-ray analysis. 1 and 2 are the first 13-epi-neoverrucosane-type diterpenes that possess a sulfate group.
  • Shin-ichi Kondo, Takashi Suzuki, Takuya Toyama, Yumihiko Yano
    2005 Volume 78 Issue 7 Pages 1348-1350
    Published: 2005
    Released: July 01, 2005
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    The halide anion recognition by 1,3-benzenedisulfonamides derived from 2-aminophenols was studied by 1H NMR titrations in MeCN-d3. The results demonstrated that the receptors achieved high recognition ability with chloride anion.
  • Shinji Toyota, Takashi Yanagihara, Yukihiro Yoshida, Michio Goichi
    2005 Volume 78 Issue 7 Pages 1351-1353
    Published: 2005
    Released: July 01, 2005
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    Bis(2,4,4″,6-tetramethyl-1,1′:3′,1″-terphenyl-2′-yl)ethyne was prepared by the Hart reaction and the Stille coupling as a sterically crowded diphenylethyne derivative. The barrier to rotation about the acetylenic axis was determined by the dynamic NMR method to be 51 kJ mol−1. The restricted rotation is attributed to the steric hindrance of the two mesityl groups in the m-terphenyl moieties.
  • Fernando Navarro Villoslada, Toshifumi Takeuchi
    2005 Volume 78 Issue 7 Pages 1354-1361
    Published: 2005
    Released: July 01, 2005
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    The combination of an experimental design/multivariate analysis method and a high-throughput technique was developed in the screening and evaluation of molecular imprinted polymers (MIPs). Combinatorial libraries of MIPs were prepared automatically at a reduced scale and screened for high affinity with regard to six experimental factors with a large impact in the MIP synthesis: the amounts of the functional monomer, cross-linker and template; the volume of the porogen, the amount of the initiator and the types of initiation. With the objective of optimizing a polymer imprinted with the non-steroidal anti-inflammatory drug piroxicam, different polymer libraries were prepared by varying the six factors according to a two-level fractional factorial design of resolution VI. This optimization resulted in polymers showing high affinity as a result, mainly, of reduced binding to the non-imprinted polymers. The type of cross-linker showed a strong influence on the specific binding of the template when assessed by equilibrium rebinding experiments. The cross-linking monomer divinylbenzene gave rise to an enhancement in the binding capacity of the MIP that may be attributed to its similar structure with the functional monomer considered (4-vinylpyridine). The binding capacity of the MIP and blank polymers was related to the six experimental factors using a partial least squares regression (PLS) method. The regression models of the polymer libraries showed the same trend in the MIP and blank polymers, suggesting a higher specific binding capacity when the polymerization was photoinitiated at low temperature; the amounts of the functional monomer and the cross-linker were similar. The proposed procedure is time and cost effective and can be used as a general tool for preparing MIPs for different analytes. The proposed method provides new insight into the influence and interaction of the main factors that affect the MIP performance that could facilitate improvements in the MIP process design in the future.
  • Weihong Zhu, Yisheng Xu, Yan Zhang, Jianping Shen, He Tian
    2005 Volume 78 Issue 7 Pages 1362-1367
    Published: 2005
    Released: July 01, 2005
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    A series of star-shaped naphthalimide derivatives (TPA-NP) were synthesized with a triphenylamine (TPA) core and chromophores at the rim. Their steady-state absorption, fluorescence, and transient fluorescence spectra were investigated, indicative of severely fluorescent quenching with regard to the corresponding 1,8-naphthalimide (NP) parent chromophores. Excitation into either the triphenylamine or naphthalimide absorption bands results in the occurrence of singlet energy transfer and photoinduced electron transfer (PIET) effectively. Single photon-counting experiments show a fast charge separation and a thermally activated back reaction. As a consequence, the fluorescent lifetime of the naphthalimide moiety in the system of TPA-NP is reduced by more than an order of magnitude, which mainly arises from the intramolecular PIET process of TPA and naphthalimide. The kinetics and PIET mechanism involving TPA-NP were elucidated.
  • Takao Sato, Hisashi Kokubo, Hiroki Fukumoto, Takakazu Yamamoto
    2005 Volume 78 Issue 7 Pages 1368-1370
    Published: 2005
    Released: July 01, 2005
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    3-Alkynyl-2,5-dibromothiophene 2 and 3,3′-dialkynyl-5,5′-dibromo-2,2′-bithiophene have been prepared. Pd-catalyzed polycondensation between 2 and 2,2′-p-[2,5-bis(dodecyloxy)-1,4-phenylene]bis(5,5-dimethyl-1,3,2-dioxaborinane) gave a novel soluble red π-conjugated polymer.
  • Tsutomu Osawa, Masashi Ando, Tadao Harada, Osamu Takayasu
    2005 Volume 78 Issue 7 Pages 1371-1372
    Published: 2005
    Released: July 01, 2005
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    The hydrogenation of methyl acetoacetate on enantio-differentiating sites of a tartaric acid-modified nickel catalyst was specifically accelerated by the addition of acetic acid to the reaction media to increase the enantio-differentiating ability of the catalyst.
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