The photophysicochemical properties and photodynamic therapy activity of phenyldiazenyl phenoxy substituted phthalocyanines when incorporated into Pluronic® F127 micelles
- Motloung, Banele M, Sekhosana, Kutloano E, Managa, Muthumuni, Prinsloo, Earl, Nyokong, Tebello
- Authors: Motloung, Banele M , Sekhosana, Kutloano E , Managa, Muthumuni , Prinsloo, Earl , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186769 , vital:44532 , xlink:href="https://doi.org/10.1016/j.poly.2019.114157"
- Description: The synthesis, photophysicochemical properties and photodynamic activity (PDT) of 4(4-phenyldiazenyl) phenoxy substituted indium (III) (InPc) and zinc (ZnPc) phthalocyanines when alone or incorporated into Pluronic_ F127 micelles are presented in this study. The InPc exhibited higher singlet oxygen (UD) at 0.47 compared to the ZnPc at 0.20 in dimethylsulfoxide. The UD values in the presence of Pluronic_ F127 and in water, were 0.32 for InPc and 0.09 for ZnPc. The triplet quantum yields (UT) were 0.92 for InPc and 0.32 for ZnPc in DMSO. The PDT activity followed the same trend as the singlet oxygen quantum yields. At the highest concentration, InPc in Pluronic_ F127 gave 22% cell viability compared to 34% for complex ZnPc. The partition coefficient Kp values were determined using the water and octanol system. InPc had a larger Kp suggesting that it is more likely to be taken up by the cancer cells, hence it exhibited better PDT activity.
- Full Text:
- Date Issued: 2019
- Authors: Motloung, Banele M , Sekhosana, Kutloano E , Managa, Muthumuni , Prinsloo, Earl , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186769 , vital:44532 , xlink:href="https://doi.org/10.1016/j.poly.2019.114157"
- Description: The synthesis, photophysicochemical properties and photodynamic activity (PDT) of 4(4-phenyldiazenyl) phenoxy substituted indium (III) (InPc) and zinc (ZnPc) phthalocyanines when alone or incorporated into Pluronic_ F127 micelles are presented in this study. The InPc exhibited higher singlet oxygen (UD) at 0.47 compared to the ZnPc at 0.20 in dimethylsulfoxide. The UD values in the presence of Pluronic_ F127 and in water, were 0.32 for InPc and 0.09 for ZnPc. The triplet quantum yields (UT) were 0.92 for InPc and 0.32 for ZnPc in DMSO. The PDT activity followed the same trend as the singlet oxygen quantum yields. At the highest concentration, InPc in Pluronic_ F127 gave 22% cell viability compared to 34% for complex ZnPc. The partition coefficient Kp values were determined using the water and octanol system. InPc had a larger Kp suggesting that it is more likely to be taken up by the cancer cells, hence it exhibited better PDT activity.
- Full Text:
- Date Issued: 2019
Electrocatalytic activity of ethynylbenzyl phthalocyanines when linked to quantum dots via click chemistry: Towards efficient oxygen reduction reaction and H2O2 oxidation
- Mpeta, Lekhetho S, Nyokong, Tebello
- Authors: Mpeta, Lekhetho S , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187037 , vital:44558 , xlink:href="https://doi.org/10.1016/j.jelechem.2019.03.064"
- Description: This work describes the conjugation of Co, Mn and Fe tetra ethynyl benzyl phthalocyanines to CdTe/ZnS quantum dots via click chemistry. The synthesized conjugates were then immobilised on glassy carbon electrode and their electrocatalytic activity towards hydrogen peroxide oxidation and oxygen reduction investigated. CoPc (1)-QDs showed superior electrocatalytic behaviour towards hydrogen peroxide catalysis with sensitivity of 2.8 × 105 μA/mM and limit of detection of 0.023 μM. On the other hand, FePc(3)-QDs showed the best oxygen reduction activity involving a direct 4-electron mechanism.
- Full Text:
- Date Issued: 2019
- Authors: Mpeta, Lekhetho S , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187037 , vital:44558 , xlink:href="https://doi.org/10.1016/j.jelechem.2019.03.064"
- Description: This work describes the conjugation of Co, Mn and Fe tetra ethynyl benzyl phthalocyanines to CdTe/ZnS quantum dots via click chemistry. The synthesized conjugates were then immobilised on glassy carbon electrode and their electrocatalytic activity towards hydrogen peroxide oxidation and oxygen reduction investigated. CoPc (1)-QDs showed superior electrocatalytic behaviour towards hydrogen peroxide catalysis with sensitivity of 2.8 × 105 μA/mM and limit of detection of 0.023 μM. On the other hand, FePc(3)-QDs showed the best oxygen reduction activity involving a direct 4-electron mechanism.
- Full Text:
- Date Issued: 2019
Photo-physicochemical properties and in vitro photodynamic therapy activity of morpholine-substituted Zinc (II)-Phthalocyanines π-π stacked on biotinylated graphene quantum dots
- Nene, Lindokuhle, Managa, Muthumuni, Nyokong, Tebello
- Authors: Nene, Lindokuhle , Managa, Muthumuni , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186993 , vital:44554 , xlink:href="https://doi.org/10.1016/j.dyepig.2019.03.002"
- Description: Two morpholine-substituted Zn(II) phthalocyanines, complex 4 and the cationic 5, were synthesized and conjugated to graphene quantum dots (GQDs) and biotinylated GQDs (GQDs-biotin) by non-covalent π-π interactions. The GQDs-biotin are prepared as potential nanoparticle-based Pc delivery vector combined with a receptor-mediated transport system using biotin. The photo-physicochemical properties of the Pc complexes and their corresponding conjugates were studied. Upon conjugation, the fluorescence quantum yields decrease for 4 and 5, however, the triplet quantum yields were increased for the conjugates. All samples demonstrated singlet oxygen generation. For conjugated complexes, the singlet quantum yields decreased due to the screening effect in some cases. An increase in the photodynamic therapy activities upon quaternization was observed for the conjugates, with the cell viability decreasing from 66.2% to 51.2% after treatment for 4-GQDs and 5-GQDs, respectively. A relatively better performance was also observed for the cationic complex in combination with the biotin functionalized GQDs, 5-GQDs-biotin, where the cell viability was 34.9% after treatment. Moreover, the cellular uptake of 5-GQDs-biotin over 24 h was relatively higher compared to Pc complex alone and other PcsGQDs conjugates.
- Full Text:
- Date Issued: 2019
- Authors: Nene, Lindokuhle , Managa, Muthumuni , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186993 , vital:44554 , xlink:href="https://doi.org/10.1016/j.dyepig.2019.03.002"
- Description: Two morpholine-substituted Zn(II) phthalocyanines, complex 4 and the cationic 5, were synthesized and conjugated to graphene quantum dots (GQDs) and biotinylated GQDs (GQDs-biotin) by non-covalent π-π interactions. The GQDs-biotin are prepared as potential nanoparticle-based Pc delivery vector combined with a receptor-mediated transport system using biotin. The photo-physicochemical properties of the Pc complexes and their corresponding conjugates were studied. Upon conjugation, the fluorescence quantum yields decrease for 4 and 5, however, the triplet quantum yields were increased for the conjugates. All samples demonstrated singlet oxygen generation. For conjugated complexes, the singlet quantum yields decreased due to the screening effect in some cases. An increase in the photodynamic therapy activities upon quaternization was observed for the conjugates, with the cell viability decreasing from 66.2% to 51.2% after treatment for 4-GQDs and 5-GQDs, respectively. A relatively better performance was also observed for the cationic complex in combination with the biotin functionalized GQDs, 5-GQDs-biotin, where the cell viability was 34.9% after treatment. Moreover, the cellular uptake of 5-GQDs-biotin over 24 h was relatively higher compared to Pc complex alone and other PcsGQDs conjugates.
- Full Text:
- Date Issued: 2019
The photo-physicochemical properties and in vitro photodynamic therapy activity of differently substituted-zinc (II)-phthalocyanines and graphene quantum dots conjugates on MCF7 breast cancer cell line
- Nene, Lindokuhle C, Managa, Muthumuni E, Oluwole, David O, Mafukidze, Donovan M, Sindelo, Azole, Nyokong, Tebello
- Authors: Nene, Lindokuhle C , Managa, Muthumuni E , Oluwole, David O , Mafukidze, Donovan M , Sindelo, Azole , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187449 , vital:44653 , xlink:href="https://doi.org/10.1016/j.ica.2019.01.012"
- Description: Several differently substituted Zn(II) phthalocyanines (ZnPcs) were prepared and conjugated to GQDs. The photophysical properties were determined for both the Pcs and their respective conjugates including the fluorescence/triplet quantum yields and lifetimes as well as the singlet oxygen generating abilities. Upon conjugation to GQDs, the fluorescence of the Pcs decreased (insignificant decrease in some cases), with an increase in the triplet quantum yields. However, the singlet quantum yields of the Pcs in the conjugates did not show an increase with the increase in the triplet quantum yields, this is suspected to be due to the screening effect. The cytotoxicity of the complexes in vitro decreased upon conjugation, as a result of the reduced actual number of Pcs units provided in the conjugate for therapy. Upon introduction of cationic charges, the photodynamic therapy activity of the complexes increased.
- Full Text:
- Date Issued: 2019
- Authors: Nene, Lindokuhle C , Managa, Muthumuni E , Oluwole, David O , Mafukidze, Donovan M , Sindelo, Azole , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187449 , vital:44653 , xlink:href="https://doi.org/10.1016/j.ica.2019.01.012"
- Description: Several differently substituted Zn(II) phthalocyanines (ZnPcs) were prepared and conjugated to GQDs. The photophysical properties were determined for both the Pcs and their respective conjugates including the fluorescence/triplet quantum yields and lifetimes as well as the singlet oxygen generating abilities. Upon conjugation to GQDs, the fluorescence of the Pcs decreased (insignificant decrease in some cases), with an increase in the triplet quantum yields. However, the singlet quantum yields of the Pcs in the conjugates did not show an increase with the increase in the triplet quantum yields, this is suspected to be due to the screening effect. The cytotoxicity of the complexes in vitro decreased upon conjugation, as a result of the reduced actual number of Pcs units provided in the conjugate for therapy. Upon introduction of cationic charges, the photodynamic therapy activity of the complexes increased.
- Full Text:
- Date Issued: 2019
Effect of bromination on the optical limiting properties at 532 nm of BODIPY dyes with p-benzyloxystyryl groups at the 3, 5-positions
- Ngoy, Bokolombe P, May, Aviwe K, Mack, John, Nyokong, Tebello
- Authors: Ngoy, Bokolombe P , May, Aviwe K , Mack, John , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187507 , vital:44665 , xlink:href="https://doi.org/10.1016/j.molstruc.2018.08.012"
- Description: The optical limiting (OL) properties of 3,5-di-p-benzyloxystyrylBODIPY dyes that contain both protons and bromine atoms at the 2,6-positions have been investigated by using the Z-scan technique at 532 nm on the nanosecond timescale. There is relatively weak absorbance at 532 nm under ambient light conditions, because the incorporation of p-benzyloxystyryl groups at the 3,5-positions results in a ca. 140 nm red shift of the main BODIPY spectral band to the 640–670 nm range. Reverse saturable absorbance (RSA) profiles that are consistent with an excited state absorption (ESA) mechanism involving the T1 and/or S1 states are observed in CH2Cl2 solution. Second order hyperpolarizability values of ca. 8 × 10−30 esu are obtained and this demonstrates that the dyes are potentially suitable for use in OL applications at 532 nm. There is a slight enhancement of the OL properties upon bromination, due to increased intersystem crossing to the triplet manifold, but the enhancement of the OL properties is less significant than has been observed with metal phthalocyanine complexes.
- Full Text:
- Date Issued: 2019
- Authors: Ngoy, Bokolombe P , May, Aviwe K , Mack, John , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187507 , vital:44665 , xlink:href="https://doi.org/10.1016/j.molstruc.2018.08.012"
- Description: The optical limiting (OL) properties of 3,5-di-p-benzyloxystyrylBODIPY dyes that contain both protons and bromine atoms at the 2,6-positions have been investigated by using the Z-scan technique at 532 nm on the nanosecond timescale. There is relatively weak absorbance at 532 nm under ambient light conditions, because the incorporation of p-benzyloxystyryl groups at the 3,5-positions results in a ca. 140 nm red shift of the main BODIPY spectral band to the 640–670 nm range. Reverse saturable absorbance (RSA) profiles that are consistent with an excited state absorption (ESA) mechanism involving the T1 and/or S1 states are observed in CH2Cl2 solution. Second order hyperpolarizability values of ca. 8 × 10−30 esu are obtained and this demonstrates that the dyes are potentially suitable for use in OL applications at 532 nm. There is a slight enhancement of the OL properties upon bromination, due to increased intersystem crossing to the triplet manifold, but the enhancement of the OL properties is less significant than has been observed with metal phthalocyanine complexes.
- Full Text:
- Date Issued: 2019
Photophysical and enhanced nonlinear optical response in asymmetric benzothiazole substituted phthalocyanine covalently linked to semiconductor quantum dots
- Nwaji, Njemuwa, Dingiswayo, Somila, Mack, John, Nyokong, Tebello
- Authors: Nwaji, Njemuwa , Dingiswayo, Somila , Mack, John , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187851 , vital:44703 , xlink:href="https://doi.org/10.1016/j.saa.2018.06.098"
- Description: The synthesis of asymmetric benzothiazole substituted phthalocyanines (complexes 3 to 5) and their covalent attachment to glutathione (GSH) functionalized quantum dots (QDs) are reported in this work. Additionally, their photophysical and nonlinear optical properties were investigated. A decrease in the fluorescence quantum yield with corresponding increase in the triplet quantum yield was observed when the complexes were covalently linked to glutathione (GSH) functionalized cadmium telluride (CdTe) quantum dots. Reverse saturable absorption was found to be predominantly dominated by excited state absorption. The observed limiting threshold values range from 0.29–0.75 J/cm2.
- Full Text:
- Date Issued: 2019
- Authors: Nwaji, Njemuwa , Dingiswayo, Somila , Mack, John , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187851 , vital:44703 , xlink:href="https://doi.org/10.1016/j.saa.2018.06.098"
- Description: The synthesis of asymmetric benzothiazole substituted phthalocyanines (complexes 3 to 5) and their covalent attachment to glutathione (GSH) functionalized quantum dots (QDs) are reported in this work. Additionally, their photophysical and nonlinear optical properties were investigated. A decrease in the fluorescence quantum yield with corresponding increase in the triplet quantum yield was observed when the complexes were covalently linked to glutathione (GSH) functionalized cadmium telluride (CdTe) quantum dots. Reverse saturable absorption was found to be predominantly dominated by excited state absorption. The observed limiting threshold values range from 0.29–0.75 J/cm2.
- Full Text:
- Date Issued: 2019
Electrocatalytic activity of a push pull Co (II) phthalocyanine in the presence of graphitic carbon nitride quantum dots
- Nxele, Siphesihle R, Oluwole, David O, Nyokong, Tebello
- Authors: Nxele, Siphesihle R , Oluwole, David O , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186746 , vital:44530 , xlink:href="https://doi.org/10.1016/j.electacta.2019.134978"
- Description: This work reports for the first time on the use of a conjugate of graphitic carbon nitride quantum dots (gCNQDs) with a push-pull asymmetrical cobalt phthalocyanine (CoPc) for electrochemical sensing. The nanocomposite is immobilized on a glassy carbon electrode (GCE) surface for the use in l-cysteine electrocatalysis. The nanocomposites were characterized using techniques such as X-ray diffractometry (XRD), Fourier transform infrared (FTIR) spectroscopy, UV-vis spectroscopy, transmission electron microscopy (TEM), energy dispersive X-ray (EDX) analysis, Raman spectroscopy and electrochemical methods. The nanocomposites were immobilized by the drop-dry method, sequentially or when premixed in solution. Good electrocatalytic oxidation of l-cysteine was observed, especially by the sequentially modified electrode surface, with the CoPc on top of gCNQDs. The sensitivity was determined as 3.5 μA.mM-1 and the limit of detection (LoD) as 101.3 μM for GCE-gCNQDs, 0.65 μA.mM-1 and 0.96 μM for GCE-CoPc, 23.41 μA.mM-1 and 0.41 μM for gCNQDs-CoPc (premixed) and 100.5 μA.mM-1 and 0.02 μM for gCNQDs-CoPc (sequential). The electrode surfaces also showed high stability by continuous cyclization.
- Full Text:
- Date Issued: 2019
- Authors: Nxele, Siphesihle R , Oluwole, David O , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186746 , vital:44530 , xlink:href="https://doi.org/10.1016/j.electacta.2019.134978"
- Description: This work reports for the first time on the use of a conjugate of graphitic carbon nitride quantum dots (gCNQDs) with a push-pull asymmetrical cobalt phthalocyanine (CoPc) for electrochemical sensing. The nanocomposite is immobilized on a glassy carbon electrode (GCE) surface for the use in l-cysteine electrocatalysis. The nanocomposites were characterized using techniques such as X-ray diffractometry (XRD), Fourier transform infrared (FTIR) spectroscopy, UV-vis spectroscopy, transmission electron microscopy (TEM), energy dispersive X-ray (EDX) analysis, Raman spectroscopy and electrochemical methods. The nanocomposites were immobilized by the drop-dry method, sequentially or when premixed in solution. Good electrocatalytic oxidation of l-cysteine was observed, especially by the sequentially modified electrode surface, with the CoPc on top of gCNQDs. The sensitivity was determined as 3.5 μA.mM-1 and the limit of detection (LoD) as 101.3 μM for GCE-gCNQDs, 0.65 μA.mM-1 and 0.96 μM for GCE-CoPc, 23.41 μA.mM-1 and 0.41 μM for gCNQDs-CoPc (premixed) and 100.5 μA.mM-1 and 0.02 μM for gCNQDs-CoPc (sequential). The electrode surfaces also showed high stability by continuous cyclization.
- Full Text:
- Date Issued: 2019
Synthesis and photophysicochemical properties of novel axially di-substituted silicon (IV) phthalocyanines and their photodynamic antimicrobial chemotherapy (PACT) activity against Staphylococcus aureus
- Sen, Pinar, Sindelo, Azole, Mafukidze, Donovan M, Nyokong, Tebello
- Authors: Sen, Pinar , Sindelo, Azole , Mafukidze, Donovan M , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186757 , vital:44531 , xlink:href="https://doi.org/10.1016/j.synthmet.2019.116203"
- Description: In this study, novel silicon (IV) phthalocyanine axially di-substituted with benzimidazole moieties (3) and its quaternized derivative (4) have been synthesized and fully characterized. The photophysical and photochemical properties of both phthalocyanines such as absorption, fluorescence and, singlet oxygen quantum yields, triplet state quantum yields and exited state lifetimes were investigated in solutions. These new silicon phthalocyanines exhibited low fluorescence but produced high singlet oxygen yields in both DMSO (compound 3 and 4) and aqueous media (compound 4). The quaternization of Si(IV)Pc (3) improved the triplet state quantum yield (ΦT) 0.61 to 0.83, consequently singlet oxygen generation (ΦΔ) increased to 0.69 from 0.42. Photodynamic antimicrobial chemotherapy activities (PACT) of Si(IV)Pc photosensitizers were determined towards Staphylococcus aureus. The higher efficiency was obtained with cationic derivative (4) giving reduction percentage value of 99.75%.
- Full Text:
- Date Issued: 2019
- Authors: Sen, Pinar , Sindelo, Azole , Mafukidze, Donovan M , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186757 , vital:44531 , xlink:href="https://doi.org/10.1016/j.synthmet.2019.116203"
- Description: In this study, novel silicon (IV) phthalocyanine axially di-substituted with benzimidazole moieties (3) and its quaternized derivative (4) have been synthesized and fully characterized. The photophysical and photochemical properties of both phthalocyanines such as absorption, fluorescence and, singlet oxygen quantum yields, triplet state quantum yields and exited state lifetimes were investigated in solutions. These new silicon phthalocyanines exhibited low fluorescence but produced high singlet oxygen yields in both DMSO (compound 3 and 4) and aqueous media (compound 4). The quaternization of Si(IV)Pc (3) improved the triplet state quantum yield (ΦT) 0.61 to 0.83, consequently singlet oxygen generation (ΦΔ) increased to 0.69 from 0.42. Photodynamic antimicrobial chemotherapy activities (PACT) of Si(IV)Pc photosensitizers were determined towards Staphylococcus aureus. The higher efficiency was obtained with cationic derivative (4) giving reduction percentage value of 99.75%.
- Full Text:
- Date Issued: 2019
New type of metal-free and Zinc (II), In (III), Ga (III) phthalocyanines carrying biologically active substituents: Synthesis and photophysicochemical properties and photodynamic therapy activity
- Sen, Pinar, Managa, Muthumuni, Nyokong, Tebello
- Authors: Sen, Pinar , Managa, Muthumuni , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186971 , vital:44552 , xlink:href="https://doi.org/10.1016/j.ica.2019.03.010"
- Description: This study reports on novel phthalocyanines having benzimidazole units which are known to have biological properties. 4-(4-(5-chloro-1H-benzo[d]imidazol-2-yl) substituted metal-free, Zn(II), In(III) and Ga(III) phthalocyanines were synthesized, these newly synthesized molecules that were substituted by oxygen bridges were fully characterized. For the purpose of determining their potency for photodynamic therapy, the photophysicochemical properties were investigated in DMSO. The H2Pc (4) showed higher fluorescence quantum yield and fluorescence lifetime as compared to metallated phthalocyanines derivatives. However, the highest singlet oxygen (ΦΔ) and triplet state quantum yields (ΦT) values were obtained with the In(III)Pc (5).
- Full Text:
- Date Issued: 2019
- Authors: Sen, Pinar , Managa, Muthumuni , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186971 , vital:44552 , xlink:href="https://doi.org/10.1016/j.ica.2019.03.010"
- Description: This study reports on novel phthalocyanines having benzimidazole units which are known to have biological properties. 4-(4-(5-chloro-1H-benzo[d]imidazol-2-yl) substituted metal-free, Zn(II), In(III) and Ga(III) phthalocyanines were synthesized, these newly synthesized molecules that were substituted by oxygen bridges were fully characterized. For the purpose of determining their potency for photodynamic therapy, the photophysicochemical properties were investigated in DMSO. The H2Pc (4) showed higher fluorescence quantum yield and fluorescence lifetime as compared to metallated phthalocyanines derivatives. However, the highest singlet oxygen (ΦΔ) and triplet state quantum yields (ΦT) values were obtained with the In(III)Pc (5).
- Full Text:
- Date Issued: 2019
A novel axially palladium (II)-Schiff base complex substituted silicon (IV) phthalocyanine
- Sen, Pinar, Nyokong, Tebello
- Authors: Sen, Pinar , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186813 , vital:44536 , xlink:href="https://doi.org/10.1016/j.poly.2019.114135"
- Description: In this study, a novel silicon(IV) phthalocyanine is reported for the first time as a phthalocyanine derivative bearing axially a palladium(II)-Schiff base complex. The photophysical and photochemical properties of the new Si(IV)Pc, such as absorption, fluorescence, singlet oxygen quantum yields, triplet state quantum yields and exited state lifetimes were measured in DMSO. The new silicon phthalocyanine displayed very low fluorescence, showing efficient intersystem crossing resulting in high triplet and high singlet oxygen quantum yields in DMSO. When compared with the unsubstituted SiPcCl2, the singlet oxygen quantum yield value (UD = 0.47) in relation to the triplet quantum yield (UT = 0.82), which is an important determinant for PDT applications, increased. The photodynamic antimicrobial chemotherapy activity (PACT) of new Si(IV)Pc towards Staphylococcus aureus was determined in comparison to the unsubstituted SiPcCl2. The results of the photodynamic antimicrobial effect study demonstrated that the Pd(II) complex substituted SiPc (5) possesses excellent photodynamic activity with a reduction percentage value of 99.94% and a log red value of 3.26.
- Full Text:
- Date Issued: 2019
- Authors: Sen, Pinar , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186813 , vital:44536 , xlink:href="https://doi.org/10.1016/j.poly.2019.114135"
- Description: In this study, a novel silicon(IV) phthalocyanine is reported for the first time as a phthalocyanine derivative bearing axially a palladium(II)-Schiff base complex. The photophysical and photochemical properties of the new Si(IV)Pc, such as absorption, fluorescence, singlet oxygen quantum yields, triplet state quantum yields and exited state lifetimes were measured in DMSO. The new silicon phthalocyanine displayed very low fluorescence, showing efficient intersystem crossing resulting in high triplet and high singlet oxygen quantum yields in DMSO. When compared with the unsubstituted SiPcCl2, the singlet oxygen quantum yield value (UD = 0.47) in relation to the triplet quantum yield (UT = 0.82), which is an important determinant for PDT applications, increased. The photodynamic antimicrobial chemotherapy activity (PACT) of new Si(IV)Pc towards Staphylococcus aureus was determined in comparison to the unsubstituted SiPcCl2. The results of the photodynamic antimicrobial effect study demonstrated that the Pd(II) complex substituted SiPc (5) possesses excellent photodynamic activity with a reduction percentage value of 99.94% and a log red value of 3.26.
- Full Text:
- Date Issued: 2019
Physicochemical and photodynamic antimicrobial chemotherapy activity of morpholine-substituted phthalocyanines: Effect of point of substitution and central metal
- Sindelo, Azole, Kobayashi, Nagao, Kimura, Mutsumi, Nyokong, Tebello
- Authors: Sindelo, Azole , Kobayashi, Nagao , Kimura, Mutsumi , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187438 , vital:44652 , xlink:href="https://doi.org/10.1016/j.jphotochem.2019.01.025"
- Description: In this study, novel metal-free, zinc and indium 1(4),8(11),15(18),22(25)-tetramorpholine (1a, 2a, 3a respectively) and 2(3), 9(10), 16(17),23(24)-tetramorpholine (1b, 2b, 3b respectively) phthalocyanines were synthesized and complexes 2 and 3 were quaternized. The photophysical and photochemical properties were investigated in dimethylsulfoxide. The non-peripherally substituted phthalocyanines generated higher singlet oxygen than the peripherally substituted phthalocyanines. Photodynamic antimicrobial chemotherapy activities towards inactivation of Escherichia coli, Staphylococcus aureus and Candida albican were evaluated, where all the quaternized Pcs showed total elimination of the micro-organism with log reductions greater than 9. Though the neutral Pcs had log reductions less than 2, for C. albican the percentage reduction was 68.5% for 2b showing the antifungal properties of the morpholine group.
- Full Text:
- Date Issued: 2019
- Authors: Sindelo, Azole , Kobayashi, Nagao , Kimura, Mutsumi , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187438 , vital:44652 , xlink:href="https://doi.org/10.1016/j.jphotochem.2019.01.025"
- Description: In this study, novel metal-free, zinc and indium 1(4),8(11),15(18),22(25)-tetramorpholine (1a, 2a, 3a respectively) and 2(3), 9(10), 16(17),23(24)-tetramorpholine (1b, 2b, 3b respectively) phthalocyanines were synthesized and complexes 2 and 3 were quaternized. The photophysical and photochemical properties were investigated in dimethylsulfoxide. The non-peripherally substituted phthalocyanines generated higher singlet oxygen than the peripherally substituted phthalocyanines. Photodynamic antimicrobial chemotherapy activities towards inactivation of Escherichia coli, Staphylococcus aureus and Candida albican were evaluated, where all the quaternized Pcs showed total elimination of the micro-organism with log reductions greater than 9. Though the neutral Pcs had log reductions less than 2, for C. albican the percentage reduction was 68.5% for 2b showing the antifungal properties of the morpholine group.
- Full Text:
- Date Issued: 2019
Magnetic nanoparticle-indium phthalocyanine conjugate embedded in electrospun fiber for photodynamic antimicrobial chemotherapy and photodegradation of methyl red
- Sindelo, Azole, Nyokong, Tebello
- Authors: Sindelo, Azole , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186857 , vital:44540 , xlink:href="https://doi.org/10.1016/j.heliyon.2019.e02352"
- Description: ClIn(III) octacarboxy phthalocyanine (ClInOCPc) when alone or conjugated to magnetic nanoparticles (MNPClInOCPc) was employed for both photodynamic antimicrobial chemotherapy of an unknown water sample and Staphylococcus aureus, and for photo-degradation of methyl red (MR). The singlet oxygen quantum yields (ΦΔ) in water using ClInOCPc and MNP-ClInOCPc embedded in polyacrylonitrile (PAN) electrospun fibers were 0.36 and 0.22, respectively. When in solution, MNP-ClInOCPc gave 90.6% photoinactivation of microbes in a water sample from the stream and of ClInOCPc resulted in 84.8 % photoinactivation. When embedded to the polymer, there was 48.0% clearance for ClInOCPc and 63.7% clearance for MNP-ClInOCPc for the microbes in the water sample from the stream. For the photo-degradation of MR, the rate of degradation increased with decrease of the MR concentration with the MNP-ClInOCPc having the fastest rate.
- Full Text:
- Date Issued: 2019
- Authors: Sindelo, Azole , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186857 , vital:44540 , xlink:href="https://doi.org/10.1016/j.heliyon.2019.e02352"
- Description: ClIn(III) octacarboxy phthalocyanine (ClInOCPc) when alone or conjugated to magnetic nanoparticles (MNPClInOCPc) was employed for both photodynamic antimicrobial chemotherapy of an unknown water sample and Staphylococcus aureus, and for photo-degradation of methyl red (MR). The singlet oxygen quantum yields (ΦΔ) in water using ClInOCPc and MNP-ClInOCPc embedded in polyacrylonitrile (PAN) electrospun fibers were 0.36 and 0.22, respectively. When in solution, MNP-ClInOCPc gave 90.6% photoinactivation of microbes in a water sample from the stream and of ClInOCPc resulted in 84.8 % photoinactivation. When embedded to the polymer, there was 48.0% clearance for ClInOCPc and 63.7% clearance for MNP-ClInOCPc for the microbes in the water sample from the stream. For the photo-degradation of MR, the rate of degradation increased with decrease of the MR concentration with the MNP-ClInOCPc having the fastest rate.
- Full Text:
- Date Issued: 2019
Synthesis and properties of chiral amide-bonded porphyrin dimers with various functional bridging blocks
- Zhu, Weihua, Haider, Syed Najeeb-uz-Zaman, Zhang, Honglin, Attatsi, Isaac K, Mack, John, Dingiswayo, Somila, Nyokong, Tebello, Song, Yuting, Xu, Haijun, Liang, Xu
- Authors: Zhu, Weihua , Haider, Syed Najeeb-uz-Zaman , Zhang, Honglin , Attatsi, Isaac K , Mack, John , Dingiswayo, Somila , Nyokong, Tebello , Song, Yuting , Xu, Haijun , Liang, Xu
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186791 , vital:44534 , xlink:href="https://doi.org/10.1016/j.dyepig.2019.107740"
- Description: Eight porphyrin dimers with various functional bridging blocks and chiral amide-bonds were synthesized and characterized. An analysis of the spectroscopy and electrochemistry has been carried out to demonstrate that the chiral properties can be modified by changing the interchromophoric through-space coupling distance between the two porphyrin chromophores by introducing various bonding and bridging blocks.
- Full Text:
- Date Issued: 2019
- Authors: Zhu, Weihua , Haider, Syed Najeeb-uz-Zaman , Zhang, Honglin , Attatsi, Isaac K , Mack, John , Dingiswayo, Somila , Nyokong, Tebello , Song, Yuting , Xu, Haijun , Liang, Xu
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186791 , vital:44534 , xlink:href="https://doi.org/10.1016/j.dyepig.2019.107740"
- Description: Eight porphyrin dimers with various functional bridging blocks and chiral amide-bonds were synthesized and characterized. An analysis of the spectroscopy and electrochemistry has been carried out to demonstrate that the chiral properties can be modified by changing the interchromophoric through-space coupling distance between the two porphyrin chromophores by introducing various bonding and bridging blocks.
- Full Text:
- Date Issued: 2019