Electrochemical behavior and detection of dopamine and ascorbic acid at an iron (II) tetrasulfophthalocyanine modified carbon paste microelectrode
- Oni, Joshua, Westbroek, Philippe, Nyokong, Tebello
- Authors: Oni, Joshua , Westbroek, Philippe , Nyokong, Tebello
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/290279 , vital:56735 , xlink:href="https://doi.org/10.1002/elan.200390104"
- Description: In this article the electrocatalytic behavior of an iron(II)tetrasulfophthalocyanine modified carbon paste microelectrode for the oxidation of dopamine (DA) and ascorbic acid (AA) is described. Although the oxidation potential of ascorbic acid is shifted by over 100 mV to more positive potentials, no peak separation could be obtained. This can be explained by the immediate homogeneous reduction of the oxidation product of dopamine by ascorbic acid in solution. However, this reaction induces a shift of the half-wave potential as a function of ratio of concentration of dopamine to ascorbic acid (cDA/cAA). Therefore it was possible to determine the cAA and cDA from this potential shift and the experimental peak current. Detection limits of 4.5±0.2×10−7 and 7.5±0.5×10−7 mol L−1 were obtained respectively for dopamine and ascorbic acid for cDA/cAA>0.01.
- Full Text:
- Date Issued: 2003
- Authors: Oni, Joshua , Westbroek, Philippe , Nyokong, Tebello
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/290279 , vital:56735 , xlink:href="https://doi.org/10.1002/elan.200390104"
- Description: In this article the electrocatalytic behavior of an iron(II)tetrasulfophthalocyanine modified carbon paste microelectrode for the oxidation of dopamine (DA) and ascorbic acid (AA) is described. Although the oxidation potential of ascorbic acid is shifted by over 100 mV to more positive potentials, no peak separation could be obtained. This can be explained by the immediate homogeneous reduction of the oxidation product of dopamine by ascorbic acid in solution. However, this reaction induces a shift of the half-wave potential as a function of ratio of concentration of dopamine to ascorbic acid (cDA/cAA). Therefore it was possible to determine the cAA and cDA from this potential shift and the experimental peak current. Detection limits of 4.5±0.2×10−7 and 7.5±0.5×10−7 mol L−1 were obtained respectively for dopamine and ascorbic acid for cDA/cAA>0.01.
- Full Text:
- Date Issued: 2003
Electrochemical behaviour of thiol-derivatised zinc (II) phthalocyanine complexes and their self-immobilised films at gold electrodes
- Ozoemena, Kenneth I, Nyokong, Tebello
- Authors: Ozoemena, Kenneth I , Nyokong, Tebello
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/290295 , vital:56737 , xlink:href="https://doi.org/10.1016/j.microc.2003.08.002"
- Description: Electrochemical properties of novel, peripherally substituted zinc phthalocyanine complex, octa(4-methylphenylthio-) phthalocyaninatozinc(II) [ZnPc(SC6H4CH3)8] (1a) in DMF solution are presented. This complex showed five quasi-reversible/reversible, diffusion-controlled redox couples. Solution voltammetry of 1a showed little contrast with that of its alkythiol-derivative, octabutylthiophthalocyaninatozinc(II) [ZnPc(SC4H9)8] (1b) in that both thiol-substituents tend to show electron-withdrawing influence on the phthalocyanine ligands; complex 1a showing easier reduction and more difficult to oxidation when compared to 1b and other alkyl derivatives. The voltammetric features of the solid ultrathin films of 1a and 1b, immobilized on gold electrodes via the self-assembling technique, are also presented. Interestingly, the self-assembled films are stable and reproducible and provide good suppression to the following Faradaic processes; gold surface oxidation, solution ion species and underpotential deposition (UPD) of copper.
- Full Text:
- Date Issued: 2003
- Authors: Ozoemena, Kenneth I , Nyokong, Tebello
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/290295 , vital:56737 , xlink:href="https://doi.org/10.1016/j.microc.2003.08.002"
- Description: Electrochemical properties of novel, peripherally substituted zinc phthalocyanine complex, octa(4-methylphenylthio-) phthalocyaninatozinc(II) [ZnPc(SC6H4CH3)8] (1a) in DMF solution are presented. This complex showed five quasi-reversible/reversible, diffusion-controlled redox couples. Solution voltammetry of 1a showed little contrast with that of its alkythiol-derivative, octabutylthiophthalocyaninatozinc(II) [ZnPc(SC4H9)8] (1b) in that both thiol-substituents tend to show electron-withdrawing influence on the phthalocyanine ligands; complex 1a showing easier reduction and more difficult to oxidation when compared to 1b and other alkyl derivatives. The voltammetric features of the solid ultrathin films of 1a and 1b, immobilized on gold electrodes via the self-assembling technique, are also presented. Interestingly, the self-assembled films are stable and reproducible and provide good suppression to the following Faradaic processes; gold surface oxidation, solution ion species and underpotential deposition (UPD) of copper.
- Full Text:
- Date Issued: 2003
Indomethacin reduces lipid peroxidation in rat brain homogenate by binding Fe2+
- Anoopkumar-Dukie, Shailendra, Lack, Barbara, McPhail, Kerry L, Nyokong, Tebello, Lambat, Zaynab, Maharaj, Deepat, Daya, Santy
- Authors: Anoopkumar-Dukie, Shailendra , Lack, Barbara , McPhail, Kerry L , Nyokong, Tebello , Lambat, Zaynab , Maharaj, Deepat , Daya, Santy
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/304763 , vital:58487 , xlink:href="https://doi.org/10.1023/A:1021958016928"
- Description: One of the hallmarks of Alzheimer's disease (AD) is the progressive degeneration of cholinergic neurons in the cerebral cortex and hippocampus. It is generally accepted that this neuronal degeneration is due to free-radical-induced damage. These free radicals attack vital structural components of the neurons. This implies that agents that reduce free radical generation could potentially delay the progression of AD. Free radical generation in the brain is assisted by the presence of iron, required by the Fenton reaction. Thus, agents that reduce iron availability for this reaction could potentially reduce free radical formation. Since non steroidal anti-inflammatory drugs (NSAIDS) have been shown to reduce the severity of AD, we investigated the possible mechanism by which indomethacin could afford neuroprotection. Our results show that indomethacin (1 mM) is able to reduce the iron-induced rise in lipid peroxidation in rat brain homogenates. In addition, our NMR data indicate that indomethacin binds the Fe2+/Fe3+ ion. This was confirmed by a study using UV/Vis spectrophotometry. The results imply that indomethacin provides a neuroprotective effect by binding to iron and thus making it unavailable for free radical production.
- Full Text:
- Date Issued: 2003
- Authors: Anoopkumar-Dukie, Shailendra , Lack, Barbara , McPhail, Kerry L , Nyokong, Tebello , Lambat, Zaynab , Maharaj, Deepat , Daya, Santy
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/304763 , vital:58487 , xlink:href="https://doi.org/10.1023/A:1021958016928"
- Description: One of the hallmarks of Alzheimer's disease (AD) is the progressive degeneration of cholinergic neurons in the cerebral cortex and hippocampus. It is generally accepted that this neuronal degeneration is due to free-radical-induced damage. These free radicals attack vital structural components of the neurons. This implies that agents that reduce free radical generation could potentially delay the progression of AD. Free radical generation in the brain is assisted by the presence of iron, required by the Fenton reaction. Thus, agents that reduce iron availability for this reaction could potentially reduce free radical formation. Since non steroidal anti-inflammatory drugs (NSAIDS) have been shown to reduce the severity of AD, we investigated the possible mechanism by which indomethacin could afford neuroprotection. Our results show that indomethacin (1 mM) is able to reduce the iron-induced rise in lipid peroxidation in rat brain homogenates. In addition, our NMR data indicate that indomethacin binds the Fe2+/Fe3+ ion. This was confirmed by a study using UV/Vis spectrophotometry. The results imply that indomethacin provides a neuroprotective effect by binding to iron and thus making it unavailable for free radical production.
- Full Text:
- Date Issued: 2003
Influence of cyclodextrins on the fluorescence, photostability and singlet oxygen quantum yields of zinc phthalocyanine and naphthalocyanine complexes
- Tau, Prudence, Ogunsipe, Abimbola O, Maree, Suzanne, Maree, M David, Nyokong, Tebello
- Authors: Tau, Prudence , Ogunsipe, Abimbola O , Maree, Suzanne , Maree, M David , Nyokong, Tebello
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/304775 , vital:58488 , xlink:href="https://doi.org/10.1142/S1088424603000562"
- Description: The effects of formation of cyclodextrin inclusion complexes on the photochemical and photophysical properties of zinc phthalocyanine (ZnPc) and various peripherally substituted zinc phthalocyanines as well as zinc naphthalocyanine (ZnNPc) are investigated. The cyclodextrins employed were the hydroxypropyl-γ-cyclodextrin and unsubstituted β-cyclodextrin. Job's plots were employed to confirm the stoichiometry of the inclusion complexes and showed 2:1 and 4:1 (cyclodextrin:phthalocyanine) inclusion behavior. The phthalocyanine inclusion complexes showed larger singlet oxygen quantum yield (ϕΔ) values when compared to the free phthalocyanines before inclusion, for complexes 1 (zinc naphthalocyanine), 2 (zinc tetranitrophthalocyanine) and 4 (zinc tetra-tert-butylphenoxyphthalocyanine). The fluorescence quantum yields generally remained unchanged following inclusion.
- Full Text:
- Date Issued: 2003
- Authors: Tau, Prudence , Ogunsipe, Abimbola O , Maree, Suzanne , Maree, M David , Nyokong, Tebello
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/304775 , vital:58488 , xlink:href="https://doi.org/10.1142/S1088424603000562"
- Description: The effects of formation of cyclodextrin inclusion complexes on the photochemical and photophysical properties of zinc phthalocyanine (ZnPc) and various peripherally substituted zinc phthalocyanines as well as zinc naphthalocyanine (ZnNPc) are investigated. The cyclodextrins employed were the hydroxypropyl-γ-cyclodextrin and unsubstituted β-cyclodextrin. Job's plots were employed to confirm the stoichiometry of the inclusion complexes and showed 2:1 and 4:1 (cyclodextrin:phthalocyanine) inclusion behavior. The phthalocyanine inclusion complexes showed larger singlet oxygen quantum yield (ϕΔ) values when compared to the free phthalocyanines before inclusion, for complexes 1 (zinc naphthalocyanine), 2 (zinc tetranitrophthalocyanine) and 4 (zinc tetra-tert-butylphenoxyphthalocyanine). The fluorescence quantum yields generally remained unchanged following inclusion.
- Full Text:
- Date Issued: 2003
Photochemical studies of binuclear phenoxysubstituted phthalocyanines containing catecholate bridges
- Seotsanyana-Mokhosi, Itumeleng, Maree, Suzanne, Maree, M David, Nyokong, Tebello
- Authors: Seotsanyana-Mokhosi, Itumeleng , Maree, Suzanne , Maree, M David , Nyokong, Tebello
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/304808 , vital:58492 , xlink:href="https://doi.org/10.1142/S1088424603000239"
- Description: Binuclear ZnPc complexes covalently bridged by catechol units have been synthesized and their absorption and photochemical properties examined. The complexes studied are 1,2-bis-2',9',16',23'-triphenoxyphthalocyaninatozinc benzene (6a), 1,2-bis-2'-9',16',23'-tri-4-carboxyphe-noxyphthalocyaninatozinc benzene (6b), 1,2-bis-2',9',16',23'-tri-4-nitrophenoxyphthalocyaninato- zinc benzene (6c) and 1,2-bis-2'-9',16',23'-tri-4-tert-butylphenoxyphthalocyaninatozinc benzene (6d). Larger intramolecular coupling was observed for 6b and 6c, containing the carboxyphenoxy and nitrophenoxy substituents, respectively, than for 6a and 6d. A single Q band peak was observed for the fluorescence spectra of 6b and 6c, whereas, 6a and 6d showed a split Q band. The absence of the high energy fluorescence peaks corresponding to absorbance peaks in the 640 nm region, suggests that the intramolecular coupling is broken by excitation for complexes 6b and 6c.
- Full Text:
- Date Issued: 2003
Photochemical studies of binuclear phenoxysubstituted phthalocyanines containing catecholate bridges
- Authors: Seotsanyana-Mokhosi, Itumeleng , Maree, Suzanne , Maree, M David , Nyokong, Tebello
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/304808 , vital:58492 , xlink:href="https://doi.org/10.1142/S1088424603000239"
- Description: Binuclear ZnPc complexes covalently bridged by catechol units have been synthesized and their absorption and photochemical properties examined. The complexes studied are 1,2-bis-2',9',16',23'-triphenoxyphthalocyaninatozinc benzene (6a), 1,2-bis-2'-9',16',23'-tri-4-carboxyphe-noxyphthalocyaninatozinc benzene (6b), 1,2-bis-2',9',16',23'-tri-4-nitrophenoxyphthalocyaninato- zinc benzene (6c) and 1,2-bis-2'-9',16',23'-tri-4-tert-butylphenoxyphthalocyaninatozinc benzene (6d). Larger intramolecular coupling was observed for 6b and 6c, containing the carboxyphenoxy and nitrophenoxy substituents, respectively, than for 6a and 6d. A single Q band peak was observed for the fluorescence spectra of 6b and 6c, whereas, 6a and 6d showed a split Q band. The absence of the high energy fluorescence peaks corresponding to absorbance peaks in the 640 nm region, suggests that the intramolecular coupling is broken by excitation for complexes 6b and 6c.
- Full Text:
- Date Issued: 2003
Phthalocyanines and related complexes as electrocatalysts for the detection of nitric oxide
- Nyokong, Tebello, Vilakazi, Sibulelo
- Authors: Nyokong, Tebello , Vilakazi, Sibulelo
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/290346 , vital:56741 , xlink:href="https://doi.org/10.1016/S0039-9140(03)00356-4"
- Description: Metallophthalocyanine (MPc) and metalloporphyrin complexes as well as some metalloproteins including myoglobin, hemoglobin, cyanocobalamin and cytochrome c catalyse the detection of nitric oxide (NO). The catalytic process often involve changes in the oxidation state of the catalyst. These complexes catalyse both the reduction and oxidation of NO. MPc complexes containing electroactive central metals such as CoPc and FePc generally show better catalytic activity towards the detection of NO than complexes containing electroinacive central metals. However, the involvement of ring based redox processes was confirmed for the homogenous NO catalysis using CoPc.
- Full Text:
- Date Issued: 2003
- Authors: Nyokong, Tebello , Vilakazi, Sibulelo
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/290346 , vital:56741 , xlink:href="https://doi.org/10.1016/S0039-9140(03)00356-4"
- Description: Metallophthalocyanine (MPc) and metalloporphyrin complexes as well as some metalloproteins including myoglobin, hemoglobin, cyanocobalamin and cytochrome c catalyse the detection of nitric oxide (NO). The catalytic process often involve changes in the oxidation state of the catalyst. These complexes catalyse both the reduction and oxidation of NO. MPc complexes containing electroactive central metals such as CoPc and FePc generally show better catalytic activity towards the detection of NO than complexes containing electroinacive central metals. However, the involvement of ring based redox processes was confirmed for the homogenous NO catalysis using CoPc.
- Full Text:
- Date Issued: 2003
Self-Assembled Monolayers of Cobalt and Iron Phthalocyanine Complexes on Gold Electrodes
- Ozoemena, Kenneth I, Nyokong, Tebello, Westbroek, Philippe
- Authors: Ozoemena, Kenneth I , Nyokong, Tebello , Westbroek, Philippe
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/290363 , vital:56743 , xlink:href="https://doi.org/10.1002/elan.200302753"
- Description: The self-assembling of the octa(hydroxyethylthio)-metallophthalocyanine {MOHETPc (M=Co and Fe)} complexes and their similar analogues, octabutylthiometallophthalocyanine {MOBTPc (M=Co and Fe)} complexes on gold electrodes are investigated. Comparative surface voltammetric insights into their distinct self-assembling properties with respect to the passivation of Faradaic processes and surface coverages, including their solution electrochemistry, suggest different orientations and non-cleavage of their CS bonds. In the pH 2−9 range, the reversible [M(III)Pc(−2)]+ / [M(II)Pc(−2)] redox couples show potential shifts close to −59 mV / pH. The gold electrodes modified with the SAMs of these species show electrocatalytic activity towards the oxidation of thiols (L-cysteine, homocysteine and penicillamine) and thiocyanate in acidic media with detection limits in the region of 10−7–10−6 mol dm−3. These monolayers are stable and easily reproducible.
- Full Text:
- Date Issued: 2003
- Authors: Ozoemena, Kenneth I , Nyokong, Tebello , Westbroek, Philippe
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/290363 , vital:56743 , xlink:href="https://doi.org/10.1002/elan.200302753"
- Description: The self-assembling of the octa(hydroxyethylthio)-metallophthalocyanine {MOHETPc (M=Co and Fe)} complexes and their similar analogues, octabutylthiometallophthalocyanine {MOBTPc (M=Co and Fe)} complexes on gold electrodes are investigated. Comparative surface voltammetric insights into their distinct self-assembling properties with respect to the passivation of Faradaic processes and surface coverages, including their solution electrochemistry, suggest different orientations and non-cleavage of their CS bonds. In the pH 2−9 range, the reversible [M(III)Pc(−2)]+ / [M(II)Pc(−2)] redox couples show potential shifts close to −59 mV / pH. The gold electrodes modified with the SAMs of these species show electrocatalytic activity towards the oxidation of thiols (L-cysteine, homocysteine and penicillamine) and thiocyanate in acidic media with detection limits in the region of 10−7–10−6 mol dm−3. These monolayers are stable and easily reproducible.
- Full Text:
- Date Issued: 2003
Solvent effects on the photochemical and fluorescence properties of zinc phthalocyanine derivatives
- Ogunsipe, Abimbola Olukayode, Maree, D, Nyokong, Tebello
- Authors: Ogunsipe, Abimbola Olukayode , Maree, D , Nyokong, Tebello
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6586 , http://hdl.handle.net/10962/d1004162 , http://dx.doi.org/10.1016/S0022-2860(03)00155-8
- Description: The effects of solvents on the singlet oxygen, photobleaching and fluorescence quantum yields for zinc phthalocyanine (ZnPc) and its derivatives; (pyridino)zinc phthalocyanine ((py)ZnPc), zinc octaphenoxyphthalocyanine (ZnOPPc) and zinc octaestronephthalocyanine (ZnOEPc), is presented. The effects of the solvents on the ground state spectra are also discussed. The largest red shift of the Q band was observed in aromatic solvents, the highest shift being observed for 1-chloronaphthalene. Higher singlet fluorescence quantum yields were observed in THF for ZnPc and ZnOPPC. Also in the same solvent phototransformation rather than photobleaching was observed for ZnOPPc. Split Q band in the emission and excitation spectra of ZnOPPc was observed in some solvents and this is explained in terms of the lowering of symmetry following excitation.
- Full Text:
- Date Issued: 2003
- Authors: Ogunsipe, Abimbola Olukayode , Maree, D , Nyokong, Tebello
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6586 , http://hdl.handle.net/10962/d1004162 , http://dx.doi.org/10.1016/S0022-2860(03)00155-8
- Description: The effects of solvents on the singlet oxygen, photobleaching and fluorescence quantum yields for zinc phthalocyanine (ZnPc) and its derivatives; (pyridino)zinc phthalocyanine ((py)ZnPc), zinc octaphenoxyphthalocyanine (ZnOPPc) and zinc octaestronephthalocyanine (ZnOEPc), is presented. The effects of the solvents on the ground state spectra are also discussed. The largest red shift of the Q band was observed in aromatic solvents, the highest shift being observed for 1-chloronaphthalene. Higher singlet fluorescence quantum yields were observed in THF for ZnPc and ZnOPPC. Also in the same solvent phototransformation rather than photobleaching was observed for ZnOPPc. Split Q band in the emission and excitation spectra of ZnOPPc was observed in some solvents and this is explained in terms of the lowering of symmetry following excitation.
- Full Text:
- Date Issued: 2003
Synthesis, spectral and electrochemical properties of a new family of pyrrole substituted cobalt, iron, manganese, nickel and zinc phthalocyanine complexes
- Obirai, Joe, Rodrigues, Nazaré Pereira, Bedioui, Fethi, Nyokong, Tebello
- Authors: Obirai, Joe , Rodrigues, Nazaré Pereira , Bedioui, Fethi , Nyokong, Tebello
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/304852 , vital:58496 , xlink:href="https://0-doi.org.wam.seals.ac.za/10.1142/S1088424603000641"
- Description: A new family of pyrrole substituted metallophthalocyanine complexes, namely cobalt(II), iron(II), manganese(III), nickel(II) and zinc(II) tetrakis-4-(pyrrol-1-yl)phenoxy phthalocyanines (noted as M(TPhPyrPc), where M is the metallic cation) have been synthesized and fully characterized. In particular, the UV-visible spectra of the iron and nickel complexes showed extensive aggregation even at low concentrations. The cyclic voltammetry of the cobalt, iron and manganese complexes showed three to four redox couples assigned to metal and ring based processes. Spectroelectrochemistry of the manganese derivative confirmed that the synthesized complex is MnIII(TPhPyrPc-2) and that the reduction of MnII(TPhPyrPc-2) to be centred on the ring and rather than on the metal, forming the MnII(TPhPyrPc-4) species. Also, the electrochemical polymerization of these newly synthesized pyrrole-substituted phthalocyanines has been demonstrated in the case of the cobalt complex and the electrocatalytic activity of the obtained film has been tested towards the oxidation of L-cysteine.
- Full Text:
- Date Issued: 2003
- Authors: Obirai, Joe , Rodrigues, Nazaré Pereira , Bedioui, Fethi , Nyokong, Tebello
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/304852 , vital:58496 , xlink:href="https://0-doi.org.wam.seals.ac.za/10.1142/S1088424603000641"
- Description: A new family of pyrrole substituted metallophthalocyanine complexes, namely cobalt(II), iron(II), manganese(III), nickel(II) and zinc(II) tetrakis-4-(pyrrol-1-yl)phenoxy phthalocyanines (noted as M(TPhPyrPc), where M is the metallic cation) have been synthesized and fully characterized. In particular, the UV-visible spectra of the iron and nickel complexes showed extensive aggregation even at low concentrations. The cyclic voltammetry of the cobalt, iron and manganese complexes showed three to four redox couples assigned to metal and ring based processes. Spectroelectrochemistry of the manganese derivative confirmed that the synthesized complex is MnIII(TPhPyrPc-2) and that the reduction of MnII(TPhPyrPc-2) to be centred on the ring and rather than on the metal, forming the MnII(TPhPyrPc-4) species. Also, the electrochemical polymerization of these newly synthesized pyrrole-substituted phthalocyanines has been demonstrated in the case of the cobalt complex and the electrocatalytic activity of the obtained film has been tested towards the oxidation of L-cysteine.
- Full Text:
- Date Issued: 2003
Synthesis, spectroscopy and photochemistry of octasubstituted thiol-derivatized phthalocyaninatozinc (II) complexes
- Ozoemena, Kenneth I, Nyokong, Tebello
- Authors: Ozoemena, Kenneth I , Nyokong, Tebello
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/290401 , vital:56746 , xlink:href="https://doi.org/10.1016/S1387-7003(03)00218-1"
- Description: Synthesis, spectroscopic and photochemical characterization of phenylthiol-derivatized zinc phthalocyanine complex: 2,3,9,10,16,17,23,24-octa(4-methylphenylthio-)phthalocyaninatozinc(II) [ZnPc(SC6H4CH3)8] (3a) and its alkanethiol derivative, 2,3,9,10,16,17,23,24-octabutylthiophthalocyaninatozinc(II) [ZnPc(SC4H9)8] (3b) are described. Spectroscopic analyses show that 3a has a higher aggregation tendency than 3b in organic solvents. Photochemical studies indicate that 3b is more photostable and more efficient at singlet oxygen generation than 3a.
- Full Text:
- Date Issued: 2003
- Authors: Ozoemena, Kenneth I , Nyokong, Tebello
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/290401 , vital:56746 , xlink:href="https://doi.org/10.1016/S1387-7003(03)00218-1"
- Description: Synthesis, spectroscopic and photochemical characterization of phenylthiol-derivatized zinc phthalocyanine complex: 2,3,9,10,16,17,23,24-octa(4-methylphenylthio-)phthalocyaninatozinc(II) [ZnPc(SC6H4CH3)8] (3a) and its alkanethiol derivative, 2,3,9,10,16,17,23,24-octabutylthiophthalocyaninatozinc(II) [ZnPc(SC4H9)8] (3b) are described. Spectroscopic analyses show that 3a has a higher aggregation tendency than 3b in organic solvents. Photochemical studies indicate that 3b is more photostable and more efficient at singlet oxygen generation than 3a.
- Full Text:
- Date Issued: 2003
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