List of Titles

Simultaneous voltammetric determination of dopamine and serotonin on carbon paste electrodes modified with iron (II) phthalocyanine complexes

- Oni, Joshua, Nyokong, Tebello

Authors: Oni, Joshua , Nyokong, Tebello
Date: 2001
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/291603 , vital:56891 , xlink:href="https://doi.org/10.1016/S0003-2670(01)00822-4"
Description: Carbon paste electrodes (CPE) containing iron(II) phthalocyanine (FePc) and iron(II) tetrasulfophthalocyanine ([FeTSPc]4−) were used for the detection of dopamine (DA) and serotonin (5-HT). Both complexes showed catalytic activity towards the detection of DA and 5-HT. The catalytic activities of [FeTSPc]4− and FePc are compared with those of [CoTSPc]4−, [NiTSPc] 4−, CoPc and NiPc complexes and with those of metal(II) tetraaminophthalocyanines (MTAPc, where M=Ni, Co or Fe) complexes. A significant improvement in the reversibility of the DA oxidation couple was observed on [FeTSPc]4− and FePc modified CPE. [FeTSPc]4− and other [MTSPc]4− modified electrodes inhibited the detection of ascorbic acid (AA), a major interferent in the detection of DA. Simultaneous detection of DA and 5-HT on [FeTSPc]4− modified CPE, in the presence of AA, showed that AA does not interfere with the determination of both species. Also no interference between DA and 5-HT was observed.
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Date Issued: 2001

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Synthesis, photophysical and photochemical studies on long chain zinc phthalocyanine derivatives

- Ogunsipe, Abimbola, Durmus, Mahmut, Atilla, Devrim, Gürek, Ayşe Gül, Ahsen, Vefa, Nyokong, Tebello

Authors: Ogunsipe, Abimbola , Durmus, Mahmut , Atilla, Devrim , Gürek, Ayşe Gül , Ahsen, Vefa , Nyokong, Tebello
Date: 2008
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/266019 , vital:53910 , xlink:href="https://doi.org/10.1016/j.synthmet.2008.06.007"
Description: The synthesis and characterization of 2,9,16,23-chloro-3,10,17,24-triethyleneoxysulphanylphthalocyaninato zinc(II) (CTESZnPc) is described. The photophysics and photochemistry of CTESZnPc and those of tetrakis(triethyleneoxysulphanyl)zinc phthalocyanine (TTESZnPc) and octakis(triethyleneoxysulphanyl)zinc phthalocyanine (OTESZnPc), are presented and compared with those of unsubstituted zinc phthalocyanine (ZnPc). The presence of triethyleneoxysulphanyl substituents on the ZnPc ring gave rise to higher values of singlet oxygen (ΦΔ) and photodegradation (ΦPd) quantum yields in DMF. However, TTESZnPc, OTESZnPc and CTESZnPc are less fluorescent than ZnPc, judging from their fluorescence quantum yield (ΦF) values. Fluorescence was lower in toluene than in DMF due to aggregation in the former solvent. Triplet quantum yield (ΦT) values were found to increase with the presence of substituents on the ZnPc ring, while triplet lifetimes (τT) were found to vary linearly with the logarithms of solvent viscosities. The fluorescences of the substituted ZnPc complexes were effectively quenched by benzoquinone (BQ), and the quenching data analyzed by the Stern–Volmer equation. The Stern–Volmer constants and the diffusion-controlled bimolecular rate constants were calculated.
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Date Issued: 2008

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Synthesis, photophysical and photochemical properties of octa-substituted antimony phthalocyanines

- Modibane, Desmond Kwena, Nyokong, Tebello

Authors: Modibane, Desmond Kwena , Nyokong, Tebello
Date: 2009
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/264226 , vital:53711 , xlink:href="https://doi.org/10.1016/j.poly.2008.11.052"
Description: This work reports on the synthesis and photophysicochemical parameters of unsubstituted [SbIIIPc]+I3- and octa-phenoxy ([SbIIIOPPc]+I3-) and -4-t-butylphenoxy ([SbIIIOTBPPc]+I3-) substituted antimony phthalocyanines. Photophysical and photochemical properties were studied for these complexes in dimethylsulfoxide, dimethylformamide and toluene. The excitation spectra of oxidized antimony (Sb(V)Pc) derivates were similar to absorption spectra. Low fluorescence quantum yields, high triplet quantum yields and low triplet lifetimes were observed as the result of heavy atom (antimony ion).
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Date Issued: 2009

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The effect of Ge, Si and Sn phthalocyanine photosensitizers on cell proliferation and viability of human oesophageal carcinoma cells

- Seotsanyana-Mokhosi, Itumeleng, Kresfelder, Tina, Abrahamse, Heidi, Nyokong, Tebello

Authors: Seotsanyana-Mokhosi, Itumeleng , Kresfelder, Tina , Abrahamse, Heidi , Nyokong, Tebello
Date: 2006
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/286115 , vital:56241 , xlink:href="https://doi.org/10.1016/j.jphotobiol.2005.12.004"
Description: The photodynamic activity of water soluble mixed sulfonated metallophthalocyanines complexes: GePcSmix, SnPcSmix and SiPcSmix on human oesophageal carcinoma (SNO) cells are reported, and compared with the activity of the unmetallated H2PcSmix and of the newly synthesized water soluble adjacently substituted binaphthalo phthalocyanine (complex 3). The alkaline phosphate (ALP) showed damage to the cell membrane in the presence of complex 3 without irradiation. The GePcSmix complex caused a relatively large increase in inflammation and a high intracellular ATP.
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Date Issued: 2006

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X-ray photoelectron spectroscopy analysis of the effect of alkyl-and arylthio substituents on manganese phthalocyanines for self-assembled monolayer formation on gold

- Coates, Megan, Nyokong, Tebello

Authors: Coates, Megan , Nyokong, Tebello
Date: 2013
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/190490 , vital:44999 , xlink:href="https://doi.org/10.1016/j.elecom.2013.03.019"
Description: Self-assembled monolayers of an octa-substituted alkylthio and arylthio manganese phthalocyanines were formed on gold. X-ray photoelectron spectroscopy was used to analyse both of the phthalocyanine layers on gold. Approximately 60% of the sulphur groups in the aryl substituted-SAM surface were bound to gold through the cleavage of the C S bond, as opposed to only 37% for the alkyl substituted-SAM.
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Date Issued: 2013

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Novel cationic-chalcone phthalocyanines for photodynamic therapy eradication of S. aureus and E. coli bacterial biofilms and MCF-7 breast cancer

- Openda, Yolande Ikala, Babu, Balaji, Nyokong, Tebello

Authors: Openda, Yolande Ikala , Babu, Balaji , Nyokong, Tebello
Date: 2022
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/300129 , vital:57895 , xlink:href="https://doi.org/10.1016/j.pdpdt.2022.102863"
Description: New tetrasubstituted zinc (II) and indium (III) phthalocyanines bearing dimethylamino chalcone group (complexes 3 and 4) as well as their quaternized analogs (3a and 4a) have been assessed for their photodynamic therapy (PDT) of cancer as well as photodynamic antimicrobial chemotherapy activities against biofilms and planktonic cultures of pathogenic bacteria of Staphylococcus aureus and Escherichia coli. Compared to the non-quaternized phthalocyanines 3 and 4, the cationic phthalocyanines 3a and 4a exhibit a higher photodynamic inactivation against the planktonic cells with log reduction values above 9 at a concentration of 1.25 µM. This was attributed to the positive charge which enhances cellular uptake. More interestingly, 3a and 4a show a higher photodynamic inactivation (less than 3% of S. aureus survived) on their biofilm counterparts thanks to their stronger affinity to these cells. 3a and 4a Pcs also exhibited interesting PDT activity against MCF-7 cancer cells giving IC50 values of 17.9 and 7.4 μM, respectively following 15 min irradiation. The obtained results in this work show that the positively charged phthalocyanines 3a and 4a are potential antibacterial photosensitizers that show some selectivity toward the Gram-positive and Gram-negative bacteria as well as MCF-7 breasts cancer cells.
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Date Issued: 2022

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Catalytic activity of iron and cobalt phthalocyanine complexes towards the oxidation of cyclohexene using tert-butylhydroperoxide and chloroperoxybenzoic acid

- Sehlotho, Nthapo, Nyokong, Tebello

Authors: Sehlotho, Nthapo , Nyokong, Tebello
Date: 2004
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/290257 , vital:56729 , xlink:href="https://doi.org/10.1016/j.molcata.2003.08.014"
Description: Cyclohexene oxidation using tert-butylhydroperoxide (TBHP) or chloroperoxybenzoic acid (CPBA) in the presence of iron(II) polychlorophthalocyanine (Cl16PcFe), iron(II) phthalocyanine (PcFe) and cobalt(II) phthalocyanine (PcCo), results in the formation of the following products: cyclohexene oxide, 2-cyclohexene-1-ol and 2-cyclohexene-1-one. Adipic acid was also formed after long reaction times. The selectivity for 2-cyclohexene-1-one is favoured when Cl16PcFe or PcCo catalysts are employed, while PcFe is selective towards the formation of 2-cyclohexene-1-ol. The Cl16PcFe catalyst is transformed into a μ-oxo dimer (Cl16PcFeIIIOIIIFePcCl16) during the oxidation process. The catalytic process using the unsubstituted PcCoII and PcFeII catalysts involved PcMIII species as an intermediate. The active form of the Cl16PcFe catalyst was stable to degradation in that it was still active even after 4 weeks of continued catalysis.
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Date Issued: 2004

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The development visions and attitudes towards urban forestry of officials responsible for greening in South African towns

- Gwedla, Nanamhla, Shackleton, Charlie M

Authors: Gwedla, Nanamhla , Shackleton, Charlie M
Date: 2015
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/180856 , vital:43651 , xlink:href="https://doi.org/10.1016/j.landusepol.2014.07.004"
Description: The planting and maintenance of trees in public areas of South African towns is the responsibility of local municipalities. Therefore, it is necessary to appreciate the visions and attitudes of municipal officials and decision-makers in charge of such activities for an understanding of the distribution and abundance of trees along streets and in urban green spaces. We hypothesised that the town size and relative wealth and current extent of trees in public places would influence the visions of such officials. We therefore conducted 24 semi-structured interviews with the officials responsible for urban tree planting in 24 towns in the Eastern Cape province, whilst also assessing the abundance of street trees via GIS counts. The density of street trees was variable, ranging from 0.5 to 9.5 trees/ha. There were significantly positive relationships between town size, relative wealth measures and street tree density. Several of the managers did not include environmental issues or trees in vision of the future for their town, although most did. There was no relationship between the managers’ visions for the future and attitudes and current street tree density. Most of the managers experienced several constraints in trying to implement their vision, notably a lack of funds for urban forestry, limited space for tree planting in low-cost housing developments, vandalism, and lack of skilled personnel.
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Date Issued: 2015

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Investigation of electrocatalytic behaviour of low symmetry cobalt phthalocyanines when clicked to azide grafted carbon electrodes

- Mpeta, Lakethe S, Sen, Pinar, Nyokong, Tebello

Authors: Mpeta, Lakethe S , Sen, Pinar , Nyokong, Tebello
Date: 2020
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/186304 , vital:44483 , xlink:href="https://doi.org/10.1016/j.jelechem.2020.113896"
Description: This work describes the electrochemical properties of low symmetry cobalt phthalocyanines namely, tris-[(4-tert-butylphenoxy)-4-(pent-4-yn-1-yloxy) phthalocyaniato] cobalt (II) (3) and tris-[(4-tert-butylphenoxy)-4-(4-ethybylbenzyl-oxy) phthalocyaniato] cobalt (II) (5). The complexes were characterized by a number of techniques including UV–Vis, mass, and infrared spectra, as well as elemental analysis. The glassy carbon electrodes were first azide functionalized then clicked to low symmetry phthalocyanines. The click reaction was confirmed using X-ray photoelectron spectra. The constructed electrodes showed excellent electrocatalytic activity towards hydrazine oxidation. Oxidation peaks with low potentials of 0.21 V and 0.26 V, for complexes 3 and 5, respectively were obtained. Complex-5 gave a better detection limit of 0.94 μM and electrocatalytic rate constant of 5.6 × 106 M−1 s−1.
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Date Issued: 2020

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Can local use assist in controlling invasive alien species in tropical forests?: The case of Lantana camara in southern India

- Kannan, Ramesh, Shackleton, Charlie M, Krishnan, Smitha, Shaanker, Ramanan U

Authors: Kannan, Ramesh , Shackleton, Charlie M , Krishnan, Smitha , Shaanker, Ramanan U
Date: 2016
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/180423 , vital:43387 , xlink:href="https://doi.org/10.1016/j.foreco.2016.06.016"
Description: Many invasive alien species (IAS) are used by local communities for a variety of subsistence and income generating purposes. This frequently poses a conflict of interest for their removal due to forest conservation and biodiversity concerns. However, if local use can simultaneously check or control specific IAS, the conflict can be avoided and both development and forest conservation perspectives accommodated in the short to medium term. We examine this for Lantana camara invasion in southern India through assessment of the demand for and impacts of harvesting on this globally problematic IAS. We interviewed local artisans regarding their knowledge and quantities of Lantana used, along with forest surveys to estimate Lantana densities and size classes in harvested and unharvested sites, and lastly we undertook controlled cutting in moist and dry deciduous forests in both the wet and dry seasons to examine rate of regrowth and mortality. Over the entire study area the abundance of Lantana far outweighed local demand, but at small scales around villages, density and size classes were significantly reduced through harvesting. The controlled cutting experiment showed marked seasonal differences, with the most severe cutting intensity resulting in significant mortality when Lantana plants were cut in the wet season, but with limited effect when cut in the dry season. We conclude that promoting local use of IAS may be a feasible approach in controlling them and thereby limiting their impacts in forests.
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Date Issued: 2016

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Electrocatalytic oxidation of amitrole and diuron on iron (II) tetraaminophthalocyanine-single walled carbon nanotube dendrimer

- Mugadza, Tawanda, Nyokong, Tebello

Authors: Mugadza, Tawanda , Nyokong, Tebello
Date: 2010
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/262611 , vital:53536 , xlink:href="https://doi.org/10.1016/j.electacta.2009.12.051"
Description: FeTAPc-single walled carbon nanotube (SWCNT) dendrimers are employed as glassy carbon electrode modifiers for the electrocatalytic oxidations of amitrole and diuron. The catalytic rate constants were 4.55 × 103 M−1 s−1 and 1.79 × 104 M−1 s−1 for amitrole and diuron, respectively using chronoamperometric studies. The diffusion constants were found to be 1.52 × 10−4 cm2 s−1 and 1.91 × 10−4 cm2 s−1 for diuron and amitrole, respectively. The linear concentration range for both were from 5.0 × 10−5 to 1.0 × 10−4 M and sensitivities of 0.6603 μA/μM and 0.6641 μA/μM for amitrole and diuron, with corresponding limits of detection of 2.15 × 10−7 and 2.6 × 10−7 M using the 3δ notation, respectively.
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Date Issued: 2010

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Equilibrium and kinetic studies of the reaction between pyridine and cobalt (II) phthalocyanine in DMSO

- Nyokong, Tebello

Authors: Nyokong, Tebello
Date: 1995
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/293380 , vital:57080 , xlink:href="https://doi.org/10.1016/0277-5387(95)00090-F"
Description: Kinetics and equilibria for the reaction between pyridine and cobalt(II) phthalocyanine [CoPc] (H2Pc = phthalocyanine) in dimethyl sulphoxide (DMSO) were studied at 25°C. The complex, CoPc(py)2, is formed in two consecutive steps. The formation of the mono-substituted CoPc(py)(DMSO) occurs first with a pseudo-first-order rate constant of k1f = 7.7 ± 0.3 × 10−3 dm3 mol−1 s−1. The final disubstituted CoPc(py)2 complex is formed with k2f= 1.1 ± 0.1 × 10−4dm3mol−1−1. The equilibrium constants were found to be K1 = 160 ± 20dm3 mol−1 and K2 = 15 ± 3 dm3mol−1 for the formation of CoPc(py)(DMSO) and CoPc(py)2, respectively.
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Date Issued: 1995

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The effects of point of substitution on the electrochemical behavior of new manganese phthalocyanines, tetra-substituted with diethylaminoethanethiol

- Akinbulu, Isaac Adebayo, Nyokong, Tebello

Authors: Akinbulu, Isaac Adebayo , Nyokong, Tebello
Date: 2010
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/249137 , vital:51781 , xlink:href="https://doi.org/10.1016/j.ica.2010.06.003"
Description: The syntheses and comparative studies of the spectral, voltammetry and spectroelectrochemical properties of new manganese phthalocyanine complexes, tetra-substituted with diethylaminoethanethio at the peripheral (complex 3a) and non-peripheral positions (complex 3b) are reported. Solution electrochemistry of complex 3a showed quasi-reversible metal-based (MnIIIPc−2/MnIIPc−2, E1/2 = −0.07 V vs. Ag|AgCl) and ring-based (MnIIPc−2/MnIIPc−3, E1/2 = −0.78 V vs. Ag|AgCl) reductions, but no ring-based oxidation. However, complex 3b showed weak irreversible ring-oxidation signal (Ep = +0.86 vs. Ag|AgCl). Reversible metal-based (MnIIIPc−2/MnIIPc−2, E1/2 = −0.04 V vs. Ag|AgCl) and ring-based (MnIIPc−2/MnIIPc−3, E1/2 = −0.68 V vs. Ag|AgCl) reductions were also observed for complex 3b. Spectroelectrochemistry was used to confirm these processes. Reduction process involving the metal (MnIIIPc−2/MnIIPc−2) was associated with the formation of manganese μ-oxo complex in complex 3a.
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Date Issued: 2010

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Electrode modification using nanocomposites of boron or nitrogen doped graphene oxide and cobalt (II) tetra aminophenoxy phthalocyanine nanoparticles

- Shumba, Munyaradzi, Nyokong, Tebello

Authors: Shumba, Munyaradzi , Nyokong, Tebello
Date: 2016
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/188699 , vital:44777 , xlink:href="https://doi.org/10.1016/j.electacta.2016.02.166"
Description: Reduced graphene oxide nanosheets (rGONS), reduced boron doped graphene oxide nanosheets (rBDGONS) and reduced nitrogen doped graphene oxide nanosheets (rNDGONS) and their composites with cobalt tetra aminophenoxy phthalocyanine nanoparticles (CoTAPhPcNP) were employed towards the detection of hydrogen peroxide. The nanomaterials were characterized by absorption spectroscopy, transmission electron microscopy, scanning electron microscopy, Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, linear sweep voltammetry and cyclic voltammetry. rNDGONS showed excellent electrooxidation and electroreduction of hydrogen peroxide supported by superior surface coverage values. The inclusion of nanosized Pc significantly lowered the reduction overpotential. CoTAPhPcNP-rNDGONS-GCE gave a sensitivity of 39.30 mA/M, catalytic rate constant of 1 × 103 M−1 s−1 and a detection limit of 8.2 nM. An adsorption equilibrium constant and Gibbs free energy of 1.26 × 103 M−1 and −17.69 kJ mol−1 respectively were observed.
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Date Issued: 2016

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Electrocatalytic activity of manganese tetra 4-aminophenyl porphyrin in the presence of graphene quantum dots

- Jokzai, Mbulelo, Mpeta, Lekhetho S, Nyokong, Tebello

Authors: Jokzai, Mbulelo , Mpeta, Lekhetho S , Nyokong, Tebello
Date: 2021
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/231443 , vital:49888 , xlink:href="https://doi.org/10.1016/j.molstruc.2015.02.040"
Description: A manganese tetra 4-aminophenyl porphyrin (MnTAPP) was synthesized and attached to graphene quantum dots (GQDs) via covalent and π-π interaction to give MnTAPP@GQDs and MnTAPP--GQDs, respectively. There was an increase (using dynamic light scattering and transmission electron microscopy) in size of the GQDs in the presence of the porphyrin due to aggregation. The porphyrins in the absence and presence of GQDs were then adsorbed onto a glassy carbon electrode using drop and dry method. The electrochemical behavior was tested by cyclic voltammetry and chronoamperometry towards hydrazine. Both methods of combining MnTAPP with GQDs improved the activity of the electrocatalysis compared to individual components. MnTAPP@GQDs showed better catalytic rate constant of 4.36 × 102 Ms−1 and lowest LoD of 0.0023 mM followed by MnTAPP--GQDs. Furthermore, the sensor showed good selectivity in the presence of interfering analytes. All probes showed good stability.
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Date Issued: 2021

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Effect of bovine serum albumin and single walled carbon nanotube on the photophysical properties of zinc octacarboxy phthalocyanine

- Ogbodu, Racheal O, Nyokong, Tebello

Authors: Ogbodu, Racheal O , Nyokong, Tebello
Date: 2014
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/189806 , vital:44933 , xlink:href="https://doi.org/10.1016/j.saa.2013.10.064"
Description: This work reports on the photophysical parameters of the conjugate between zinc octacarboxy phthalocyanine (ZnOCPc) and bovine serum albumin (BSA) represented as ZnOCPc–BSA (1) which was further adsorbed onto single walled carbon nanotubes (SWCNT) represented as (ZnOCPc–BSA–SWCNT 2). ZnOCPc (without BSA) was also adsorbed on SWCNT represented as ZnOCPc–SWCNT (3). The presence of BSA resulted in the increase in singlet oxygen quantum yield (ΦΔ) for 1 (at ΦΔ = 0.44) and 2 (at ΦΔ = 0.41) compared to ΦΔ = 0.21 for ZnOCPc alone. For complex 3 which did not contain BSA singlet oxygen quantum yield decreased.
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Date Issued: 2014

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Solvent and central metal effects on the photophysical and photochemical properties of peripherally tetra mercaptopyridine substituted metallophthalocyanines

- Moeno, Sharon, Nyokong, Tebello

Authors: Moeno, Sharon , Nyokong, Tebello
Date: 2009
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/263522 , vital:53635 , xlink:href="https://doi.org/10.1016/j.jphotochem.2009.01.021"
Description: The synthesis of peripherally tetra 2-mercaptopyridine substituted phthalocyanines containing Si, Ga, Sn and In as central metal ions is reported for the first time in this study. Photophysical and photochemical studies were carried out on these compounds in order to determine the potential of the complexes as photosensitizers for use in photodynamic therapy. Fluorescence quantum yields (ΦF) ranged from 0.012 to 0.2 and triplet quantum yields (ΦT) from 0.54 to 0.89 in dimethylformamide (DMF) and from 0.65 to 0.93 in dimethylsulfoxide (DMSO). The triplet lifetimes ranged from 20 to 130 μs, the low values are due to the heavy atom effects of the central metal. The triplet lifetimes were larger in DMSO when compared with DMF.
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Date Issued: 2009

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Synthesis and electrochemical characterisation of new tantalum (V) alkythio phthalocyanines

- Chauke, Vongani, Nyokong, Tebello

Authors: Chauke, Vongani , Nyokong, Tebello
Date: 2010
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/249093 , vital:51777 , xlink:href="https://doi.org/10.1016/j.ica.2010.05.003"
Description: The synthesis and electrochemical characterisation of octa-pentylthio (4a) and octa-octylthio (4b) – phthalocyaninato tantalum (III) hydroxide are hereby reported. These TaPc complexes absorb in the near infrared region (∼800 nm in dichloromethane). They show good solubility in most common solvents especially non-viscous solvents such as dichloromethane and chloroform. NMR, mass and infrared spectroscopy and elemental analysis confirmed the structures and purity of the synthesised complexes. The cyclic voltammograms (CVs) showed reversible reduction couples and irreversible oxidation peaks. The latter exhibited adsorption behavior. The reduction processes were observed at −0.74 and −1.13 V (versus Ag|AgCl) for 4a, and −0.67, −1.02 and −1.48 V (versus Ag|AgCl) for 4b. Spectroelectrochemistry confirmed one metal reduction, with the rest of the redox processes being centered on the phthalocyanine ring.
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Date Issued: 2010

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