Applications of lead phthalocyanines embedded in electrospun fibers for the photoinactivation of Escherichia coli in water
- Osifeko, Olawale L, Nyokong, Tebello
- Authors: Osifeko, Olawale L , Nyokong, Tebello
- Date: 2014
- Language: English
- Type: Article
- Identifier: vital:7304 , http://hdl.handle.net/10962/d1020381
- Description: Lead (II) pyridyloxyphthalocyanine (PbTpyPc) and its quaternized form (PbTepyPc) were synthesized and the photophysical behavior examined. Low fluorescence quantum yields (ΦF) of 0.01 and 0.02 were observed for PbTepyPc and PbTpyPc, respectively. The singlet oxygen quantum yields (ΦΔ) were 0.60 and 0.68, for PbTepyPc and PbTpyPc, respectively using DPBF as a quencher in DMF. Singlet oxygen production of the embedded sensitizers in electrospun fiber were quantified using ADMA and were found to be ΦΔ = 0.41 and ΦΔ = 0.21 for PbTepyPc and PbTpyPc, respectively. Photodynamic inactivation of Escherichia coli (E. coli) with the quaternized photosensitizer at 5 μM, totally inactivated the E. coli (with log CFU = 10 decrease). Only 0.4 log CFU decrease was obtained with PbTpyPc. The embedded non-quaternized photosensitizer (PbTpyPc) was less active on the gram negative bacteria but the quaternized photosensitizer (PbTepyPc) was effective towards inactivation of E. coli. , Original publication is available at http://dx.doi.org/10.1016/j.dyepig.2014.05.010
- Full Text: false
- Date Issued: 2014
- Authors: Osifeko, Olawale L , Nyokong, Tebello
- Date: 2014
- Language: English
- Type: Article
- Identifier: vital:7304 , http://hdl.handle.net/10962/d1020381
- Description: Lead (II) pyridyloxyphthalocyanine (PbTpyPc) and its quaternized form (PbTepyPc) were synthesized and the photophysical behavior examined. Low fluorescence quantum yields (ΦF) of 0.01 and 0.02 were observed for PbTepyPc and PbTpyPc, respectively. The singlet oxygen quantum yields (ΦΔ) were 0.60 and 0.68, for PbTepyPc and PbTpyPc, respectively using DPBF as a quencher in DMF. Singlet oxygen production of the embedded sensitizers in electrospun fiber were quantified using ADMA and were found to be ΦΔ = 0.41 and ΦΔ = 0.21 for PbTepyPc and PbTpyPc, respectively. Photodynamic inactivation of Escherichia coli (E. coli) with the quaternized photosensitizer at 5 μM, totally inactivated the E. coli (with log CFU = 10 decrease). Only 0.4 log CFU decrease was obtained with PbTpyPc. The embedded non-quaternized photosensitizer (PbTpyPc) was less active on the gram negative bacteria but the quaternized photosensitizer (PbTepyPc) was effective towards inactivation of E. coli. , Original publication is available at http://dx.doi.org/10.1016/j.dyepig.2014.05.010
- Full Text: false
- Date Issued: 2014
Behavior of Palladium Nanoparticles in the Absence or Presence of Cobalt Tetraaminophthalocyanine for the Electrooxidation of Hydrazine
- Maringa, Audacity, Nyokong, Tebello
- Authors: Maringa, Audacity , Nyokong, Tebello
- Date: 2014
- Language: English
- Type: Article
- Identifier: vital:7305 , http://hdl.handle.net/10962/d1020382
- Description: We report on the electrodeposition of palladium nanoparticles (PdNPs) on a glassy carbon electrode (GCE) and onto a poly-CoTAPc-GCE (CoTAPc=cobalt tetraamino phthalocyanine) surface. The electrodes are denoted as PdNPs-GCE and PdNPs/poly-CoTAPc-GCE, respectively. PdNPs/poly-CoTAPc-GCE showed the best activity for the oxidation of hydrazine at the lowest potential of −0.28 V and with the highest currents. The results were further supported by electrochemical impedance spectroscopy (EIS) which showed that there was less resistance to charge transfer for PdNPs/poly-CoTAPc-GCE compared to PdNPs-GCE. The catalytic rate constant for hydrazine oxidation was 6.12×108 cm3 mol−1 s−1 using PdNPs/poly-CoTAPc-GCE. , Original publication is available at http://dx.doi.org/10.1002/elan.201400028
- Full Text: false
- Date Issued: 2014
- Authors: Maringa, Audacity , Nyokong, Tebello
- Date: 2014
- Language: English
- Type: Article
- Identifier: vital:7305 , http://hdl.handle.net/10962/d1020382
- Description: We report on the electrodeposition of palladium nanoparticles (PdNPs) on a glassy carbon electrode (GCE) and onto a poly-CoTAPc-GCE (CoTAPc=cobalt tetraamino phthalocyanine) surface. The electrodes are denoted as PdNPs-GCE and PdNPs/poly-CoTAPc-GCE, respectively. PdNPs/poly-CoTAPc-GCE showed the best activity for the oxidation of hydrazine at the lowest potential of −0.28 V and with the highest currents. The results were further supported by electrochemical impedance spectroscopy (EIS) which showed that there was less resistance to charge transfer for PdNPs/poly-CoTAPc-GCE compared to PdNPs-GCE. The catalytic rate constant for hydrazine oxidation was 6.12×108 cm3 mol−1 s−1 using PdNPs/poly-CoTAPc-GCE. , Original publication is available at http://dx.doi.org/10.1002/elan.201400028
- Full Text: false
- Date Issued: 2014
Effects of pyrene on the photophysical and two-photon absorption-based nonlinear optical properties of indium(III) phthalocyanines
- Sanusi, Kayode, Nyokong, Tebello
- Authors: Sanusi, Kayode , Nyokong, Tebello
- Date: 2014
- Language: English
- Type: Article
- Identifier: vital:7314 , http://hdl.handle.net/10962/d1020540
- Description: Photophysical and two-photon-dependent nonlinear absorption properties of two chloroindium(III) phthalocyanines bearing pyrene units have been investigated. The tetra- (3) and the tri- (4) pyrene-substituted phthalocyanines exhibit strong triplet absorption with high triplet yields () of 0.79 and 0.83, respectively. The measured nonlinear optical data, such as the two photon absorption cross-sections, the third- and second-order nonlinearities were found to be comparable with those of literature, thus, making the compounds promising candidates for a broad range of nonlinear optical applications. , Original publication is available at http://dx.doi.org/10.1080/00958972.2014.959509
- Full Text: false
- Date Issued: 2014
- Authors: Sanusi, Kayode , Nyokong, Tebello
- Date: 2014
- Language: English
- Type: Article
- Identifier: vital:7314 , http://hdl.handle.net/10962/d1020540
- Description: Photophysical and two-photon-dependent nonlinear absorption properties of two chloroindium(III) phthalocyanines bearing pyrene units have been investigated. The tetra- (3) and the tri- (4) pyrene-substituted phthalocyanines exhibit strong triplet absorption with high triplet yields () of 0.79 and 0.83, respectively. The measured nonlinear optical data, such as the two photon absorption cross-sections, the third- and second-order nonlinearities were found to be comparable with those of literature, thus, making the compounds promising candidates for a broad range of nonlinear optical applications. , Original publication is available at http://dx.doi.org/10.1080/00958972.2014.959509
- Full Text: false
- Date Issued: 2014
Photophysical behavior of Zn aminophenoxy substituted phthalocyanine conjugates with carboxylic acid-coated silica nanoparticles: Effect of point of substitution
- Fashina, Adedayo, Antunes, Edith M, Nyokong, Tebello
- Authors: Fashina, Adedayo , Antunes, Edith M , Nyokong, Tebello
- Date: 2014
- Language: English
- Type: Article
- Identifier: vital:7318 , http://hdl.handle.net/10962/d1020563 , Original publication is available at http://dx.doi.org/10.1016/j.molstruc.2014.04.034
- Description: This work reports on the grafting of silica nanoparticles with zinc phthalocyanine complexes tetra-substituted non-peripherally and peripherally with a 4-amino phenoxy group. The phthalocyanine dyes have free amino groups, facilitating covalent attachment of the dyes on the silica surface via amide bond formation. The surface area of the functionalized silica nanoparticles increased on conjugation but the pore volumes were reduced. The phthalocyanine functionalized silica nanoparticles showed lower fluorescence quantum yields as well as shorter triplet lifetimes compared to the free phthalocyanines in dimethyl formamide. For the non-peripherally substituted phthalocyanines increases in triplet yield quantum yields, lifetimes, and singlet oxygen quantum yields were observed.
- Full Text: false
- Date Issued: 2014
- Authors: Fashina, Adedayo , Antunes, Edith M , Nyokong, Tebello
- Date: 2014
- Language: English
- Type: Article
- Identifier: vital:7318 , http://hdl.handle.net/10962/d1020563 , Original publication is available at http://dx.doi.org/10.1016/j.molstruc.2014.04.034
- Description: This work reports on the grafting of silica nanoparticles with zinc phthalocyanine complexes tetra-substituted non-peripherally and peripherally with a 4-amino phenoxy group. The phthalocyanine dyes have free amino groups, facilitating covalent attachment of the dyes on the silica surface via amide bond formation. The surface area of the functionalized silica nanoparticles increased on conjugation but the pore volumes were reduced. The phthalocyanine functionalized silica nanoparticles showed lower fluorescence quantum yields as well as shorter triplet lifetimes compared to the free phthalocyanines in dimethyl formamide. For the non-peripherally substituted phthalocyanines increases in triplet yield quantum yields, lifetimes, and singlet oxygen quantum yields were observed.
- Full Text: false
- Date Issued: 2014
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