The effects of the additions of protic and aprotic polar solvents on the emission spectrum of 4-phenyl-1-N,N-dimethylaminobutane (PDAB) in THF have been studied under conditions of steady-state illumination. The fluorescence spectrum of PDAB in THF was reported to consist of three component bands (band A at 285 nm (fluorescence of the phenyl group), band B at 343 nm (fluorescence of the amino group) and band C at 385 nm (emission from an intramolecular exciplex)). The intensities of bands B and C decreased with increasing solvent polarity. They also decreased owing to the hydrogen-bonding interaction between the amino group in PDAB and protic solvents, but in this case the intensity of band A was found to increase. Acetonitrile has only a polar effect and trichloroacetic acid only a hydrogen-bonding (or protonation) effect, while alcohols have both effects. The equilibrium constants for the formation of intermolecular hydrogen-bonded complexes of the amino group with alcohols were estimated from the intensity change of band A. The hydrogen-bonding and polar effects of alcohols on the intensities of bands B and C could be separately evaluated. The decrease in the intensities of bands B and C with increasing solvent polarity in THF-AN and THF-alcohol mixtures is considered to be caused by the conversion of the exciplex to an ion-pair enhanced by the increase in solvent polarity.
en-copyright= kn-copyright= en-aut-name=GuobinXie en-aut-sei=Guobin en-aut-mei=Xie kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=NakamuraMayuko en-aut-sei=Nakamura en-aut-mei=Mayuko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=SueishiYoshimi en-aut-sei=Sueishi en-aut-mei=Yoshimi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=YamamotoShunzo en-aut-sei=Yamamoto en-aut-mei=Shunzo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil= kn-affil=Okayama University affil-num=2 en-affil= kn-affil=Okayama University affil-num=3 en-affil= kn-affil=Okayama Univresity affil-num=4 en-affil= kn-affil=Okayama University en-keyword=solvent effect kn-keyword=solvent effect en-keyword=polar effect kn-keyword=polar effect en-keyword=hydrogen-bonding kn-keyword=hydrogen-bonding en-keyword=fluorescence kn-keyword=fluorescence en-keyword=exciplex kn-keyword=exciplex END start-ver=1.4 cd-journal=joma no-vol=162 cd-vols= no-issue=2-3 article-no= start-page=449 end-page=456 dt-received= dt-revised= dt-accepted= dt-pub-year=2004 dt-pub=20043 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Effects of alcohols on emission spectra of toluene-triethylamine mixtures in THF: separation into polar and hydrogen-bonding interactions en-subtitle= kn-subtitle= en-abstract= kn-abstract=The emission spectra of toluene (T)?triethylamine (TEA) systems were measured under conditions of steady-state illumination in some protic and aprotic solvent?THF mixtures. The fluorescence spectrum of the T?TEA system in THF could be separated into three component bands (band A at 279 nm (fluorescence of T), band B at 336 nm (fluorescence of TEA) and band C at 373 nm (emission from an intermolecular exciplex)). The intensities of bands B and C decreased with increasing solvent polarity. The decrease in the intensities of bands B and C is considered to be caused by the enhanced conversion of the exciplex to an ion-pair with increase in solvent polarity. The intensities of bands B and C also decreased owing to the hydrogen-bonding interaction between TEA and protic solvents, but in this case the intensity of band A increased. Acetonitrile only has a polar effect and trichloroacetic acid only has a hydrogen-bonding (or protonation) effect, while alcohols have both effects. The equilibrium constants for the formation of intermolecular hydrogen-bonded complexes of TEA with alcohols were estimated from the changes in the intensity of band A. The hydrogen-bonding and polar effects of alcohols on the intensities of bands B and C could be evaluated separately. The ratio of the hydrogen-bonding effect to the polar effect of alcohols was observed to increase with increasing vol.% of alcohol.
en-copyright= kn-copyright= en-aut-name=XieGuobin en-aut-sei=Xie en-aut-mei=Guobin kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=SueishiYoshimi en-aut-sei=Sueishi en-aut-mei=Yoshimi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=YamamotoShunzo en-aut-sei=Yamamoto en-aut-mei=Shunzo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= affil-num=1 en-affil= kn-affil=Okayama University affil-num=2 en-affil= kn-affil=Okayama University affil-num=3 en-affil= kn-affil=Okayama University en-keyword=solvent effect kn-keyword=solvent effect en-keyword=polar effect kn-keyword=polar effect en-keyword=hydrogen-bonding kn-keyword=hydrogen-bonding en-keyword=fluorescence kn-keyword=fluorescence en-keyword=exciplex kn-keyword=exciplex END start-ver=1.4 cd-journal=joma no-vol=54 cd-vols= no-issue=3-4 article-no= start-page=233 end-page=239 dt-received= dt-revised= dt-accepted= dt-pub-year=2006 dt-pub=20064 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Elucidation of the role of the complex in hydride transfer reaction between methylene blue and 1-benzyl-1,4-dihydronictinamide by effect of γ-cyclodextrin en-subtitle= kn-subtitle= en-abstract= kn-abstract=The kinetics of the hydride transfer reaction between Methylene Blue (MB+) and 1-benzyl-1,4-dihydronicotinamide (BNAH) were studied in 10 % ethanol-90 % water mixed solvents containing β- and γ-cyclodextrins (β-CD and γ-CD). The pseudo-first order rate constant shows kinetic saturation at high initial concentration of BNAH. This indicates the formation of a complex between MB+ and BNAH. The reaction was suppressed by addition of β-CD, but enhanced by addition of γ-CD. MB+ and BNAH were separately accommodated within the β-CD cavity and the cavity walls may protect the activity site of the reactants. On the other hand, in the MB+-BNAH-γ-CD system, the inclusion of the complex between MB+ and BNAH with γ-CD occurred. This effect of γ-CD can distinguish between the productive and non-productive nature of the complex.
en-copyright= kn-copyright= en-aut-name=LiuYingin en-aut-sei=Liu en-aut-mei=Yingin kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=HotouchiNaoto en-aut-sei=Hotouchi en-aut-mei=Naoto kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=SueishiYoshimi en-aut-sei=Sueishi en-aut-mei=Yoshimi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=YamamotoShunzo en-aut-sei=Yamamoto en-aut-mei=Shunzo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil= kn-affil=Okayama University affil-num=2 en-affil= kn-affil=Okayama University affil-num=3 en-affil= kn-affil=Okayama University affil-num=4 en-affil= kn-affil=Okayama University en-keyword=hydride transfer reaction kn-keyword=hydride transfer reaction en-keyword=reaction mechanism kn-keyword=reaction mechanism en-keyword=cyclodextrin kn-keyword=cyclodextrin en-keyword=inclusion complexes kn-keyword=inclusion complexes en-keyword=1-benzyl-1 kn-keyword=1-benzyl-1 en-keyword=4-dihydronicotinamide kn-keyword=4-dihydronicotinamide en-keyword=Methylene Blue kn-keyword=Methylene Blue END start-ver=1.4 cd-journal=joma no-vol=37 cd-vols= no-issue=7 article-no= start-page=1005 end-page=1014 dt-received= dt-revised= dt-accepted= dt-pub-year=2008 dt-pub=20080624 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Kinetic study of the reaction of leuco methylene blue with 2,6-dimethyl-p-benzoquinone in a reverse micellar system en-subtitle= kn-subtitle= en-abstract= kn-abstract=The kinetics of the reaction of leuco methylene blue (MBH) with 2,6-dimethyl-p-benzoquinone (DMBQ) were studied in a heptane/bis(2-ethylhexyl)-sulfosuccinate (AOT)/water reverse micellar system. The pseudo-first-order rate constant (k (obsd)) obtained in the presence of excess of DMBQ was found to be proportional to the initial concentration of DMBQ for W (0)=3, 5, 10, 15 and 20 (W (0)=[H2O]/[AOT]). The second-order rate constant (k (2)=k (obsd)/[DMBQ](0)) increased with an increase in the W (0) value, but was almost independent of the concentration of the water pool. A mechanism involving the distribution of DMBQ between the reverse micellar interface and bulk organic solvent was proposed to explain these findings.
en-copyright= kn-copyright= en-aut-name=UsuiDaisuke en-aut-sei=Usui en-aut-mei=Daisuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=SueishiYoshimi en-aut-sei=Sueishi en-aut-mei=Yoshimi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=YamamotoShunzo en-aut-sei=Yamamoto en-aut-mei=Shunzo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= affil-num=1 en-affil= kn-affil=The Graduate School of Natural Science and Technology, Okayama University affil-num=2 en-affil= kn-affil=The Graduate School of Natural Science and Technology, Okayama University affil-num=3 en-affil= kn-affil=The Graduate School of Natural Science and Technology, Okayama University en-keyword=reverse micelle kn-keyword=reverse micelle en-keyword=AOT kn-keyword=AOT en-keyword=oxidation kn-keyword=oxidation en-keyword=leuco methylene blue kn-keyword=leuco methylene blue en-keyword=kinetics kn-keyword=kinetics en-keyword=water pool kn-keyword=water pool END start-ver=1.4 cd-journal=joma no-vol=49 cd-vols= no-issue=12 article-no= start-page=4064 end-page=4066 dt-received= dt-revised= dt-accepted= dt-pub-year=2011 dt-pub=201110 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Analysis of bis(trifluoromethylsulfonyl)imide-doped paramagnetic graphite intercalation compound using F-19 very fast magic angle spinning nuclear magnetic resonance en-subtitle= kn-subtitle= en-abstract= kn-abstract=F atoms bonding to paramagnetic/conductive graphene layers in accepter-type graphite intercalation compounds (GICs) are analyzed using very fast magic angle spinning nuclear magnetic resonance, which is applied for the first time on F-19 nuclei to investigate paramagnetic materials. In the bis(trifluoromethylsulfonyl)imide(TFSI)-doped GIC, C-F bonds between fluorine atoms and graphene layers conform to a weak bonding of F to the graphene sheets. TFSI anions intercalated in the GIC do not show overall molecular motion; even at room temperature only the CF3 groups rotate. en-copyright= kn-copyright= en-aut-name=GotohKazuma en-aut-sei=Gotoh en-aut-mei=Kazuma kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=TakedaKazuyuki en-aut-sei=Takeda en-aut-mei=Kazuyuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=LernerMichael M. en-aut-sei=Lerner en-aut-mei=Michael M. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=SueishiYoshimi en-aut-sei=Sueishi en-aut-mei=Yoshimi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=MaruyamaShinpei en-aut-sei=Maruyama en-aut-mei=Shinpei kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=GotoAtsushi en-aut-sei=Goto en-aut-mei=Atsushi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=TanshoMasataka en-aut-sei=Tansho en-aut-mei=Masataka kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=OhkiShinobu en-aut-sei=Ohki en-aut-mei=Shinobu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=HashiKenjiro en-aut-sei=Hashi en-aut-mei=Kenjiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=ShimizuTadashi en-aut-sei=Shimizu en-aut-mei=Tadashi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= en-aut-name=IshidaHiroyuki en-aut-sei=Ishida en-aut-mei=Hiroyuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=11 ORCID= affil-num=1 en-affil= kn-affil=Okayama Univ affil-num=2 en-affil= kn-affil=Kyoto Univ affil-num=3 en-affil= kn-affil=Oregon State Univ affil-num=4 en-affil= kn-affil=Okayama Univ affil-num=5 en-affil= kn-affil=Okayama Univ affil-num=6 en-affil= kn-affil=Natl Inst Mat Sci affil-num=7 en-affil= kn-affil=Natl Inst Mat Sci affil-num=8 en-affil= kn-affil=Natl Inst Mat Sci affil-num=9 en-affil= kn-affil=Natl Inst Mat Sci affil-num=10 en-affil= kn-affil=Natl Inst Mat Sci affil-num=11 en-affil= kn-affil=Okayama Univ END start-ver=1.4 cd-journal=joma no-vol=64 cd-vols= no-issue=2 article-no= start-page=143 end-page=147 dt-received= dt-revised= dt-accepted= dt-pub-year=2019 dt-pub=20190301 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Heat Treatments of Ginger Root Modify but Not Diminish Its Antioxidant Activity as Measured With Multiple Free Radical Scavenging (MULTIS) Method en-subtitle= kn-subtitle= en-abstract= kn-abstract= Ginger (Zingiber officinale Rosc.) root (or rhizome) has been reported to have antioxidant properties such as reactive oxygen species scavenging activities. Using multiple free-radical scavenging method, we have newly determined the scavenging abilities of ginger roots against five reactive oxygen species, i.e., HO?, O2 -?, RO?, tert-BuOO?, and 1O2. After heating grated ginger roots at 80C for 2 h, nearly 50% decrease in scavenging ability was recorded against 1O2 and tert-BuOO?. Conversely, the O2 -? scavenging ability increased by about 56% after heat treatment. Based on the antioxidant activity measurement of the ginger's components, i.e., 6-gingerol, 6-shogaol, and zingerone, active species acting as antioxidant capacity of ginger was shown. Additionally, ginger's antioxidant capacity was quantitatively compared with that of rosemary extract, indicating that rosemary is peroxyl specific scavenger while ginger has higher scavenging ability against HO? and 1O2. en-copyright= kn-copyright= en-aut-name=SueishiYoshimi en-aut-sei=Sueishi en-aut-mei=Yoshimi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=MasamotoHiroaki en-aut-sei=Masamoto en-aut-mei=Hiroaki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KotakeYashige en-aut-sei=Kotake en-aut-mei=Yashige kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= affil-num=1 en-affil=Department of Chemistry, Faculty of Science, Okayama University kn-affil= affil-num=2 en-affil=Department of Chemistry, Faculty of Science, Okayama University kn-affil= affil-num=3 en-affil=RRINC-USA kn-affil= en-keyword=ESR spin trapping kn-keyword=ESR spin trapping en-keyword=MULTIS kn-keyword=MULTIS en-keyword=antioxidant capacity kn-keyword=antioxidant capacity en-keyword=ginger kn-keyword=ginger en-keyword=multiple free-radical scavenging method. kn-keyword=multiple free-radical scavenging method. END start-ver=1.4 cd-journal=joma no-vol=85 cd-vols= no-issue=9 article-no= start-page=2737 end-page=2744 dt-received= dt-revised= dt-accepted= dt-pub-year=2020 dt-pub=20200825 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A comparative study of the antioxidant profiles of olive fruit and leaf extracts against five reactive oxygen species as measured with a multiple free]radical scavenging method en-subtitle= kn-subtitle= en-abstract= kn-abstract=Olive fruits and leaves are recognized to have great potential as natural sources of antioxidants. The major phenolic antioxidant component in these plant tissues is oleuropein. The antioxidant activity of olive fruits and leaves was evaluated in this study using multiple free]radical scavenging (MULTIS) methods, wherein we determined the scavenging abilities of different extracts against five reactive oxygen species (ROS; HO?, O2??, RO?, t]BuOO?, and 1O2). Raw olive fruits taste bitter and are inedible without undergoing a debittering treatment. Following the NaOH]debittering process, the radical scavenging activity of olives decreased by 90%. The MULTIS measurements indicated that oleuropein and hydroxytyrosol are responsible for the radical scavenging activity of olive fruits. Furthermore, we evaluated the radical scavenging profiles of olive leaf extracts against five ROS and found significant seasonal variations in their antioxidant activities. Leaves picked in August possessed greater radical scavenging abilities (180% to 410% for different ROS) than those picked in the cold season (December and February). In roasted olive leaves, we found marked increases (230% to 300% and 180% to 220%) in the antioxidant activities of Maillard reaction products against RO? and t]BuOO?, respectively. This study presented a useful comparative analysis of the antioxidant capacities of food against various types of ROS. en-copyright= kn-copyright= en-aut-name=SueishiYoshimi en-aut-sei=Sueishi en-aut-mei=Yoshimi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=NiiRisako en-aut-sei=Nii en-aut-mei=Risako kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= affil-num=1 en-affil=Department of Chemistry, Faculty of Science, Okayama University kn-affil= affil-num=2 en-affil=Department of Chemistry, Faculty of Science, Okayama University kn-affil= en-keyword=antioxidant capacity kn-keyword=antioxidant capacity en-keyword=fruit extract kn-keyword=fruit extract en-keyword=leaf extract kn-keyword=leaf extract en-keyword=MULTIS kn-keyword=MULTIS en-keyword=olive kn-keyword=olive END