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1.
The coordination of nitric oxide (NO) to cobalt(II) phthalocyanine (CoPc) in dimethyl sulphoxide (DMSO) has been studied. CoPc coordinates with NO in a 1:1 ratio, forming a CoPc(NO) species. The IR band observed at 1680 cm−1 is assigned to the coordinated NO. In the presence of excess NO, pseudo first order kinetics were followed. The observed rate constant, kf, was determined to be 15.0±0.3 dm−3 mol−1 s−1 and the equilibrium constant was K=5.4±0.4×104dm3 mol−1. Solution or adsorbed CoPc catalyses the reduction of NO. The products of reduction include NH3 and NH2OH. 相似文献
2.
Electrocatalytic oxidation and detection of hydrazine in pH 7.0 conditions were studied by using gold electrode modified with self-assembled monolayer (SAM) films of iron phthalocyanine (FePc) complex axially ligated to a preformed 4-mercaptopyridine SAMs. The anodic oxidation of hydrazine in neutral pH conditions with FePc-linked-mercaptopyridine-SAM-modified gold electrode occurred at low overpotential (0.35 V versus Ag|AgCl) and the treatment of the voltammetric data showed that it was a pure diffusion-controlled reaction with the involvement of one electron in the rate-determining step. The mechanism for the interaction of hydrazine with the FePc-SAM is proposed to involve the Fe(III)Pc/Fe(II)Pc redox process. Using cyclic voltammetry (CV) and Osteryoung square wave voltammetry (OSWV), hydrazine was detected over a linear concentration range of 1.3 × 10−5 to 9.2 × 10−5 mol/L with low limits of detection (ca. 5 and 11 μM for OSWV and CV, respectively). At concentrations higher than 1.2 × 10−4 mol/L the anodic peak potential shifted to 0.40 V (versus Ag|AgCl), and this was interpreted to be due to kinetic limitations resulting from the saturation of hydrazine and its oxidation products onto the redox-active monolayer film. This type of metallophthalocyanine-SAM-based electrode is a highly promising electrochemical sensor given its ease of fabrication, good catalytic activity, stability, sensitivity and simplicity. 相似文献
3.
Synthesis,Characterization, and Electronic Structures of Porphyrins Fused with Polycyclic Aromatic Ring Systems 下载免费PDF全文
Prof. Dr. Tetsuo Okujima Dr. John Mack Dr. Jun Nakamura Gugu Kubheka Prof. Dr. Tebello Nyokong Dr. Hua Zhu Naoki Komobuchi Prof. Dr. Noboru Ono Prof. Dr. Hiroko Yamada Prof. Dr. Hidemitsu Uno Prof. Dr. Nagao Kobayashi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(41):14730-14738
A series of porphyrins fused with acenaphthylene, phenanthroline, and benzofluoranthene polycyclic aromatic rings were prepared by means of a 3+1 porphyrin synthesis approach and subsequent retro‐Diels–Alder reaction of bicyclo[2.2.2]octadiene‐fused precursors. Analysis of the magnetic circular dichroism spectra and the results of time‐dependent DFT calculations are used to identify the reasons for the trends observed in the wavelengths and relative intensities of the Q bands of the products. Michl's perimeter model is used as a conceptual framework to explain the changes in the relative energies of the frontier π‐molecular orbitals. 相似文献
4.
Four types of water-soluble luminescent quantum dots (QDs) whose surface was functionlaized with thioglycolic acid (TGA), 3-mercaptopropionic acid (MPA), or glutathione (GSH), were investigated for the sensitive and selective detection of hydroxyl radical (●OH) in aqueous media. It was found that the type of capping agent and QD influenced the sensitivity of the probe. The order of sensitivity of the probe was: GSH-CdTe@ZnS > MPA-CdTe@ZnS > TGA-CdTe > MPA-CdTe QDs. Under the optimum conditions, a limit of detection as low as 8.5?×?10-8?M was obtained using GSH-CdTe@ZnS. The effects of foreign reactive oxygen species and the Fenton reactants and products as possible interferences on the proposed probe were negligible for CdTe@ZnS QDs. Besides, experimental results indicated that CdTe@ZnS QDs were more attractive for the selective recognition of ●OH than CdTe QDs. The mechanistic reaction pathway between the QDs and ●OH is proposed. 相似文献
5.
The photophysical and photochemical properties of tetraaminophthalocyanine complexes of lutetium and zinc covalently linked to polyacrylic acid were studied alongside those of unsubstituted zinc phthalocyanine within the same polymeric fiber matrix. All three phthalocyanines within the solid fiber matrices showed photoactivity by the generation of singlet oxygen as was observed in solution. The fluorescence behaviors of the composite fibers equally parallel those in solution. For the unsubstituted zinc phthalocyanine composite, the fiber showed fluorescence quenching on interaction with gaseous nitrogen dioxide similar to that in DMF and, thus could be a promising nanofabric material in developing optoelectronic devices that are responsive to the gas. 相似文献
6.
A symmetrical cardanol-based cobalt phthalocyanine (Pc) along with its asymmetrical acid-based derivatives were synthesized and applied in the electrocatalysis of hydrazine. Despite the inhibition of electron movement by the bulky cardanol-based substituent throughout the series of molecules, an ideal combination of substituents was established in GCE- 3 (2,9,16-tris(3-pentadecylphenoxy)-23-mono propionic acid phthalocyanato cobalt (II)) where a limit of detection (LoD) value of 5.10 μM (signal to noise ratio=5) was recorded for the detection of hydrazine. The results obtained serve as an illustration that the combination of electron-donating and electron-withdrawing substituents has a significant influence on the complete functioning of the phthalocyanine molecule(s) being investigated. 相似文献
7.
Development of Graphene/CdSe Quantum Dots‐Co Phthalocyanine Nanocomposite for Oxygen Reduction Reaction 下载免费PDF全文
Nanocomposites containing CdSe quantum dots, tetra(4‐(4,6‐diaminopyrimidin‐2‐ylthio) phthalocyaninatocobalt(II)) (CoPyPc) and reduced graphene nanosheets (rGNS) were devoloped and used for the modification of a glassy carbon electrode. Characterization of the nanocomposites was done by transmission electron microscopy (TEM) and X‐ray diffraction (XRD) analyses. Cyclic voltammetry (CV) was used for electrochemical characterization of the prepared nanocomposite for oxygen reduction reaction. The oxygen reduction activity for rGNS/CdSe‐CoPyPc nanocomposite was found to be superior over the individual nanomaterials in this study. The activity of the nanocomposite towards oxygen reduction was also tested for tolerance to methanol crossover effect using chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) studies. 相似文献
8.
Msimelelo P. Siswana Kenneth Ikechukwu Ozoemena Daniela A. Geraldo Tebello Nyokong 《Journal of Solid State Electrochemistry》2010,14(8):1351-1358
This work reports for the first time that nanostructured nickel (II) phthalocyanine/multiwalled carbon nanotubes composite supported on a basal plane pyrolytic electrode (NiPcNP/MWCNT-BPPGE) could potentially serve as a viable platform for the sensitive electrocatalytic detection of asulam pesticide at phosphate-buffered solution (pH 7.0 conditions). Comparative electron transfer dynamics, using ferrocyanide/ferricyanide as outer sphere redox probe, were examined and interpreted using the Davies–Compton theoretical framework dealing with voltammetry at spatially heterogeneous electrodes. The NiPcNP/MWCNT-BPPGE exhibits fast electron transport and excellent electrocatalytic behavior toward asulam, with an onset potential of about 150 mV lower than observed for the electrode without MWCNTs or bare BPPGE. Also, NiPcNP/MWCNT-BPPGE displayed good analytical performance for asulam, with a detection limit of 0.285 µM, a linear concentration range of 91–412 µM, and a sensitivity of 44.6 µA mM?1. 相似文献
9.
Mamie Sancy Jorge Pavez Miguel A. Gulppi Ivanildo Luiz de Mattos Ramiro Arratia‐Perez Cristian Linares‐Flores Maritza Paez Tebello Nyokong José H. Zagal 《Electroanalysis》2011,23(3):711-718
We have studied the trends in catalytic activity of several Co macrocyclics confined on the surface graphite electrodes for the oxidation of thiocyanate. A plot of log i (at constant E) versus the formal potential of the catalyst gives a volcano correlation, indicating that the Co(II/I) redox potential needs to be tuned, in order to achieve maximum reactivity. Graphite electrodes modified with Co phthalocyanine at pH 4 exhibit linear amperometric response for thiocyanate concentration in the range 10?7 and 10?3 M. Theoretical calculations show that electrocatalytic activity (as log i at constant E) plotted versus the energy of the LUMO of the Co complex also gives a volcano correlation. 相似文献
10.
Electrode Modification Using Alkynyl Substituted Fe(II) Phthalocyanine via Electrografting and Click Chemistry for Electrocatalysis 下载免费PDF全文
In this work, tetrakis(5‐hexyn‐oxy)Fe(II) phthalocyanine was synthesised in order to perform a click reaction between the terminal alkyne groups and an azide group on a glassy carbon electrode (GCE) surface. An azide group was formed on the electrode surface following electrografting using 4‐azidobenzene diazonium tetrafluoroborate by electrochemical reduction. The Cu(I) catalyzed alkyne‐azide Huisgen cycloaddition reaction was then employed in order to react the terminal alkyne groups on the phthalocyanine with the azide groups on the GCE surface. The modified electrode was employed to catalyse the oxidation of hydrazine. The electrode showed good electrocatalytic ability towards the detection of hydrazine with a sensitivity of 15.38 µA mM?1 and a limit of detection of 1.09 µM. 相似文献