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1.
K. J. Thomas K. George Thomas T. K. Manojkumar Suresh Das M. V. George 《Journal of Chemical Sciences》1994,106(6):1375-1382
A cyanine chromoionophore1 has been synthesised and its photophysical properties have been investigated. Complexation with alkali metal cations (Li+ and Na+) brings about a significant shift in the absorption and emission spectra to shorter wavelengths, which is accompanied by
an enhancement in the fluorescence quantum yield. These effects can be attributed to the suppression of intramolecular charge
transfer processes of the cyanine dye, brought about by complexation with the metal cations.
Dedicated to Professor C N R Rao on his sixtieth birthday
Contribution No. RRLT-PRU-42 from the Regional Research Laboratory, Trivandrum 相似文献
2.
Hong-bo Li Meng-an Hao Chuan Qin Wen-bing Yang Xiao-ping Hu Sheng-ying Qin 《Reaction Kinetics and Catalysis Letters》2007,91(2):299-306
Cobalt (II) hydroxamates with the benzo-15-crown-5 (B15C5) pendant have been synthesized and characterized. These complexes
were successfully employed to the oxidation of p-xylene to p-toluic acid with air at 110°C under normal atmospheric pressure. The effects of the B15C5 pendant, the length of chain bonding
of B15C5 in these complexes and the addition of alkali metal ions on the oxidation for p-xylene are also investigated by the comparison with the crown-free analogue. 相似文献
3.
Javad Zolgharnein Ghasem Shahmoradi Saeid Amani 《Journal of inclusion phenomena and macrocyclic chemistry》2008,60(1-2):163-167
The complexation reaction of phenylaza-15-crwon-5, 4- nitrobenzo- 15-crown-5, and benzo-15-crown-5 with Ag+, Tl+ and Pb2+ ions in methanol solution have been studied by a competitive potentiometric method. The Ag+/Ag electrode used both as an indicator and reference electrode in a concentration cell. The emf of cell monitored as the
crown ethers concentration varies through the titration. The stoichiometry and stability constants of resulting complexes
have been evaluated by MINIQUAD. The stoichiometry for all resulting complexes was 1:1. The stability of these metal ions
with derivatives of 15-crown-5 are in order phenylaza-15-crown-5 > Benzo-15-crown-5 > 4-nitrobenzo-15-crown-5, and for the
each used crown ethers are as Pb2+ > Ag+ > Tl+. The effect of the substituted group on the stability of resulting complexes was considered. The obtained results are novel
and interesting. 相似文献
4.
Anastasia D. Zubenko Bayirta V. Egorova Lyubov S. Zamurueva Stepan N. Kalmykov Olga A. Fedorova 《Mendeleev Communications》2021,31(2):194-196
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5.
1mThODUCnONThestudyofsupermolecularcomplexesofcrownetherringhasthrivedforyearsrecentlybecauseoftheirprobabilityprospectinmaterialscienceandlifescience,andtheirinterestingstereochemistrywhentheradiusofcavityofringischanged"'.Inthecourseofourinvestigationontherelationshipbetweenthesizeofthecrownetherringandthepolymerizationofpolyoxometalate,anovel'crystalofsupermolecularcomplexof[Na(N--(p--chlorophenyl)aza--15--crown--5)(Et,O)j2(Na,W,.5Mo,.5O,,)wasobtained.2EXPERIMENTALToasolutionofequ… 相似文献
6.
7.
Maryam Khoshroo Abbas A. Rostami Saeed Yeganegi 《Monatshefte für Chemie / Chemical Monthly》2008,139(7):781-787
A glassy carbon (GC) surface modified with monolayer of 4-bromophenyl was examined as voltammetric electrode for some redox
systems. The modified electrode exhibited very slow electron transfer in comparison to the unmodified surface by factors which
varied with the redox systems. However, after scanning the modified electrode in 0.1 M tetrabutylammonium tetrafluoroborate (TBABF4) in acetonitrile from 0.4 to −1.1 V vs. Ag/AgCl for 20–25 cycles, the modified electrode showed much faster electron transfer kinetics, e.g., the results for Fe(CN)6
3−/4− were approaching those observed with unmodified surfaces. The effect is attributed to an apparently irreversible structural
change in the 4-bromophenyl monolayer, which increases the rate of electron tunneling. The transition to the conducting state
is associated with electron injection into the monolayer and causes a significant decrease in the calculated HOMO-LUMO gap
for the monolayer molecule. Once the monolayer is switched to the conducting state, it supports rapid electron exchange with
the redox system, but not with dopamine, which requires adsorption to the electrode surface. A conductive surface modified
electrode may have useful properties for electroanalytical applications and possibly in electrocatalysis.
Correspondence: Abbas A. Rostami, Department of Chemistry, Faculty Basic of Science, University of Mazandaran, Babolsar, Iran. 相似文献
8.
9.
Novel 5-oxazolone derivatives containing an N-phenyl-aza-15-crown-5 moiety were synthesized for the first time. The structures of the new derivatives were confirmed by 1H NMR, 13C NMR and FT-IR. In addition, evaluation of the visible absorption and emission properties of the structures were carried out in eight different solvents. The products show intense visible absorption maxima in the range 467-524 nm, and fluoresced strongly, with emission maxima from 496 to 689 nm in all the solvents tested. 相似文献
10.
利用循环伏安法将次甲基蓝修饰到玻碳电极表面,制备了聚次甲蓝修饰电极(PMB/GCE),并研究了此电极的化学性质及对叶酸的电化学响应特性.在磷酸盐缓冲液中PMB/GCE电极对叶酸有良好的催化作用并出现一个灵敏的还原峰,用循环伏安法测得峰电流与叶酸的浓度在0.1×10-3~2.9×10 -3 mol/L范围内呈良好线性关系... 相似文献
11.
The electrochemical behavior of some podands at a benzo[c]cinnoline modified glassy carbon electrode
Aybüke A. ?sb?r Zafer Üstünda? Selen B?lge Amgalan Natsagdorj Emine Kiliç Zeynel Kiliç 《Analytica chimica acta》2005,547(1):59-63
This paper describes the grafting of benzo[c]cinnoline (BCC) molecules on glassy carbon (GC) electrode surface. The attachment of BCC molecules to carbon substrate is induced by the electrochemical reduction of the corresponding diazonium salt. The modification of GC with BCC diazonium salt was done in aprotic solution and proved by blocking of dopamine electron transfer. The presence of BCC at the GC surface was characterized by cyclic voltammetry and X-ray photoelectron spectroscopy (XPS). On modified surface, the electrochemical behavior of two different types of podands and the catalytic effects of the GC-BCC surface were studied. The XPS was used to monitor element characteristics of the adsorbates on the GC surface and confirm the attachment of BCC molecules to the GC surface. 相似文献
12.
I. S. El-Hallag A. M. Hassanein M. M. Ghoneim 《Monatshefte für Chemie / Chemical Monthly》1995,126(10):1075-1085
Summary Cyclic voltammetry (CV), convolution-deconvolution transformation of current, chronopotentiometry (CP), and digital simulation studies were used to evaluate the kinetic parameters of the electrode reaction of the hetero-bimetallic complex [MeNC(CO)2Mn(dppm)2Pt(H)(CNMe)]+PF
6
–
in dichloromethane at a glassy carbon electrode (GCE). It was found that the complex undergoes a reduction step at –0.895±0.01 V and two anodic steps at +0.903±0.01 V and 1.370±0.01 V. The reduction and oxidation steps are followed by a rapid chemical process. On the basis of the electrochemical results, an overall oxidation process was found to proceed as EEC, while the reduction process proceeds according to an ECEC scheme.
Elektrochemische Untersuchung des hetero-bimetallischen Komplexes [MeNC(CO)2Mn(dppm)2Pt(H)(CNMe)]+PF 6 – mit einer Glaskohlenstoffelektrode
Zusammenfassung Cyclische Voltammetrie (CV), Strom-Konvolution-Dekonvolution, Chronopotentiometrie und digitale Simulation wurden zur Bestimmung der kinetischen Parameter der Reaktion des hetero-bimetallischen Komplexes [MeNC(CO)2Mn(dppm)2Pt(H)(CNMe)]+PF 6 – an einer Glaskohlenstoffelektrode (GCE) in Dichlormethan eingesetzt. Der Komplex zeigt eine Reduktionsstufe bei –0.895±0.01 V und zwei anodische Stufen bei 0.903±0.01 V und 1.370±0.01 V. Auf die Reduktions-und Oxidationsschritte folgt unmittelbar ein schneller chemischer Prozeß. Aus den elektrochemischen Ergebnissen läßt sich ein Gesamtoxidationsprozeß nach einem EEC — Schema ableiten, während die Reduktion nach einem ECEC — Schema verläuft.相似文献
13.
Song Y 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2007,67(5):1169-1177
DFT-B3LYP/6-31G (d, p) and HF/6-31G (d, p) calculations are performed for deoxidized norepinephrineat (NP(R)) and its oxidized form (NP(O)). The electrochemistry of norepinephrineat (NP) was studied by cyclic voltammetry (CV) at a pyrolytic graphite electrode modified by Nafion multi-walled carbon nanotubes (MWNTs) in phosphate buffers at pH 6.0, showing that the standard electrode potential of half reaction for NP(O), H+/NP(R) is 0.75l V. This experimental standard electrode potential of half reaction is consistent with that calculated using the energies of solvation and sum of electronic and thermal free energies of NP(R) and NP(O). The frontier orbital theory and Mülliken charges of molecular explain the electrochemical behavior of CV at modified electrode well. The singlet vertical excited states for NP(R) and NP(O) are also discussed. 相似文献
14.
Crystalline [Y(OH2)3(NCMe)(benzo-15-crown-5)][ClO4]3·benzo-15-crown-5-CH3CN can be obtained by slowly cooling a reaction mixture of Y(ClO4)3·n H2O with benzo-15-crown-5 in a solution of acetonitrile and methanol (3 : 1) from 60°C to room temperature. The crystal structure of this complex has been determined at –150 and 20°C. The complex is triclinic,P
. At –150°C the cell parameters area = 11.986(4),b = 12.071(7),c = 16.364(5) Å, = 93.56(3), = 98.68(3), = 109.68(4)°, vol = 2187 Å3, andD
calc = 1.61 g cm–3 forZ = 2 formula units. 3633 independently observed [F
o 5(F
o)] reflections were used in the final least-squares refinement leading to an agreement index ofR = 0.048. The Y(III) ion coordination geometry approximates a tricapped trigonal prism with three water molecules and three benzo-15-crown-5 oxygen atoms forming the prism, with the two remaining benzo-15-crown-5 oxygen atoms and the acetonitrile molecule completing the coordination as capping atoms. The three water molecules hydrogen bond a second crown ether molecule and two of the perchlorate anions. The two acetonitrile molecules have contacts with perchlorate oxygen atoms close enough for some weak interaction. One perchlorate is ordered, one is partially disordered as is the coordinated solvent molecule, and the third anion is totally disordered. The two unique crown ether molecules have distinctively different conformations.For Part 20, see reference [1]. 相似文献
15.
Süheyla Özbey Halil Hoşgören Yilmaz Turgut Giray Topal 《Journal of inclusion phenomena and macrocyclic chemistry》2001,39(3-4):315-320
A new complex of a chiral monoaza-crown ether, [R-(-)-2-ethyl-N-benzyl-4,7,10,13-tetraoxa-1-azacyclopentadeceane) NaClO4], has been prepared and studied by x-ray diffraction. The compound crystallizes in space group P21 with cell dimensions a = 9.480(1), b = 15.978(2), c = 15.816(2) Å, = 105.51(1)°, Z = 4. The final R value is 0.055 for 2711 observed reflections and 540 parameters. There are twomolecules in the asymmetric unit labelled A and B. The sodium ion is hexacoordinated. The average values for the Na–-Oeth (etheric) distances are 2.364(6), 2.317(7) Å and the Na–N distances are 2.679(6), 2.611(7) Å; the Na–-O(ClO4) contacts are2.497(7) and 2.257(10) Å, for A and B, respectively. 相似文献
16.
Süheyla Özbey F. Betül Kaynak Mahmut Toŭrul Nadir Demirel Halil Hoşgören 《Journal of inclusion phenomena and macrocyclic chemistry》2003,45(1-2):123-128
A new complex of a chiral monoaza-crown ether, [R-(-)-2-ethyl-N-benzyl-4,7,10,13-tetraoxa-8,9-benzo-1-azacyclopentadec-8-ene...NaClO4], has been prepared and studied by x-ray diffraction. The compound crystallizes in space group P21 with cell dimensions a = 8.721(1), b = 16.318(2), c = 8.905(1) Å, = 100.80(1)°. The sodium cation is heptacoordinated and located significantly out of the best plane of the macrocycle ring. The donor atoms of the macrocycle are in the half-chair arrangement. 相似文献
17.
Toyoji Kakuchi Shigeyuki Matsunami Hiroyuki Kamimura Fumiaki Ishii Takahiro Uesaka Kazuaki Yokota 《Journal of polymer science. Part A, Polymer chemistry》1995,33(9):1431-1436
4′-Ethynylbenzo-15-crown-5 ( EB15C5 ) polymerized with high yields in the presence of (bicyclo[2.2.1] hepta-2,5-diene) rhodium(I) chloride dimer and triethylamine as a cocatalyst in chloroform at 30°C. Common catalysts for the polymerization of substituted acetylenes, WCl6 and MoCl5, did not produce any polymer from EB15C5 . The structure of the main chain for poly(4′-ethynylbenzo-15-crown-5) ( PEB15C5 ) was determined to be predomi-nantly cis form, based upon the relatively sharp signals attributed to the main chain atoms that was observed in the 1H and 13C NMR spectra. The cation-binding properties of PEB15C5 are very similar to that of poly(4′-vinylbenzo-15-crown-5), and the selectivity is in the order of K+> Rb+ ? Cs+ ? Na+, Li+. The electrical conductivity of PEB15C5 increased from 1.3 × 10?10 to 1.3 × 10?6 S. cm?1, when the polymer was doped with iodine. © 1995 John Wiley & Sons, Inc. 相似文献
18.
Javad Zolgharnein Ghasem Shahmoradi Khosrow Zamani Saeid Amani 《Journal of inclusion phenomena and macrocyclic chemistry》2007,59(1-2):99-103
The complexation reaction of phenylaza-15-crown-5, and 4-nitrobenzo-15-crown-5, benzo-15-crown-5 and dibenzopyrdino-18-crwon-6,
dibenzo-18-crown-6,dicyclohexyl-18-crown-6(cis and trans), and 18-crown-6 with Na+ ion in methanol have been studied by potentiometric method. The Na+ ion-selective electrode has been used both as indicator and reference electrode. The stoichiometry and stability constants
of complexes of these crown ethers with sodium ion were evaluated by MINIQUAD program. The major trend of stability of resulting
complexes of these macrocycle with Na+ ion varied in the order DCY18C6 > DB18C6 > 18C6 > DBPY18C6 > phenylaza-15C5 > benzo-15C5 > 4-nitrobenzo-15C5. The obtained
results in particular stability constant of complexes of DBPY18C6, phenylaza-15C5 and 4-nitrobenzo-15C5 with sodium ion in
comparison with other crowns ether are novel, and interesting. 相似文献
19.
Zbigniew GrobelnyAndrzej Stolarzewicz Barbara Morejko-Bu?Gintaras Buika Juozas V. Gra?ulevi?iusAdalbert Maercker 《European Polymer Journal》2002,38(12):2359-2363
Several reactions occur during the initiation of 2-(9-carbazolyl)ethyl glycidyl ether polymerization by K−, K+ (15-crown-5)2. At first the oxirane ring is opened mainly in the β-position. An organometallic intermediate obtained cleaved then the linear ether bond in the substituent and the cyclic one in crown ether. Various potassium alkoxides are finally formed. They are the real initiators of the polymerization. 9-Vinylcarbazole being another reaction product is inactive in this process. 相似文献
20.
Robin D. Rogers Lynn K. Kurihara Matthew M. Benning 《Journal of inclusion phenomena and macrocyclic chemistry》1987,5(5):645-658
The reaction of UO2(ClO4)·nH2O with 15-crown-5 and 18-crown-6 in acetonitrile yielded the title complexes. [UO2(OH2)5] [ClO4]2·3(15-crown-5)·CH3CN crystallizes in the triclinic space groupPT with (at–150°C)a=8.288(6),b=12.874(7),c=24.678(7) Å, =82.62(4), =76.06(5), =81.06(5)°, andD
calc=1.67 g cm–3 forZ=2 formula units. Least-squares refinement using 6248 independent observed reflections [F
o5(F
o)] led toR=0.111. [UO2(OH2)5] [ClO4]2·2(18-crown-6)·2CH3CN·H2O is orthorhombicP212121 with (at–150 °C)a=12.280(2),b=17.311(7),c=22.056(3) Å,D
calc=1.68 g cm–3,Z=4, andR=0.032 (3777 observed reflections). In each complex the crown ether molecules are hydrogen bonded to the water molecules of the pentagonal bipyramidal [UO2(OH2)5]2+ ions, each crown ether having exclusive use of two hydrogen atoms from one water molecule and one hydrogen from another water molecule. In the 15-crown-5 complex the remaining hydrogen bonding interaction is between one of the water molecules and one of the perchlorate anions. The solvent molecule has a close contact between the methyl group and a perchlorate anion suggesting a weak interaction. There are a total of three U-OH...OClO3 hydrogen bonds to the two perchlorate anions in [UO2(OH2)5] [ClO4]2·(18-crown-6)·2CH3CN ·H2O. The remaining coordinated water hydrogen bond is to the uncoordinated 2H2O molecule, which in turn is hydrogen bonded to a perchlorate oxygen atom and an acetonitrile nitrogen atom. One solvent methyl group interacts with an anion, the other with one of the 18-crown-6 molecules. Unlike the 15-crown-5 structure, the hydrogen bonding in this complex results in a polymeric network with formula units joined by hydrogen bonds from one of the solvent molecules and the uncoordinated water molecule.
Supplementary data relating to this article are deposited with the British Library as Supplementary Publication No. SUP 82051 (37 pages).For Part 10, see reference [1]. 相似文献