Improved Photophysical and Photochemical Properties of Thiopheneethoxy Substituted Metallophthalocyanines on Immobilization onto Gold‐speckled Silica Nanoparticles
- Dube, Edith, Oluwole, David O, Nyokong, Tebello
- Authors: Dube, Edith , Oluwole, David O , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187699 , vital:44688 , xlink:href="https://doi.org/10.1111/php.12879"
- Description: This work reports on the synthesis of tetrakis-[(thiophineethoxy) phthalocyaninato] indium(II) chloride (3). The photophysical behavior of complex 3 was compared to that of the Zn derivative (tetrakis-[(thiophineethoxy) phthalocyaninato] zinc(II) (complex 2)). The compounds were interacted with gold-speckled silica (GSS) nanoparticles via Au–S self assembly to afford the conjugates (2–GSS and 3–GSS). The photophysicochemical behavior of the compounds and their conjugates were assessed. The conjugates afforded a decrease in fluorescence quantum yields and lifetimes with improved triplet and singlet oxygen quantum yields in comparison with complexes 2 and 3 alone. The complexes and their conjugates could serve as good candidates for photodynamic therapy.
- Full Text:
- Date Issued: 2018
- Authors: Dube, Edith , Oluwole, David O , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187699 , vital:44688 , xlink:href="https://doi.org/10.1111/php.12879"
- Description: This work reports on the synthesis of tetrakis-[(thiophineethoxy) phthalocyaninato] indium(II) chloride (3). The photophysical behavior of complex 3 was compared to that of the Zn derivative (tetrakis-[(thiophineethoxy) phthalocyaninato] zinc(II) (complex 2)). The compounds were interacted with gold-speckled silica (GSS) nanoparticles via Au–S self assembly to afford the conjugates (2–GSS and 3–GSS). The photophysicochemical behavior of the compounds and their conjugates were assessed. The conjugates afforded a decrease in fluorescence quantum yields and lifetimes with improved triplet and singlet oxygen quantum yields in comparison with complexes 2 and 3 alone. The complexes and their conjugates could serve as good candidates for photodynamic therapy.
- Full Text:
- Date Issued: 2018
Glycosylated zinc phthalocyanine-gold nanoparticle conjugates for photodynamic therapy
- Dube, Edith, Oluwole, David O, Nwaji, Njemuwa, Nyokong, Tebello
- Authors: Dube, Edith , Oluwole, David O , Nwaji, Njemuwa , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/234524 , vital:50205 , xlink:href="https://doi.org/10.1016/j.saa.2018.05.081"
- Description: In this work, we report on the synthesis of tris-[(2,2,7,7-tetramethyltetrahydro-3aH-bis([1,3]dioxolo)[4,5-b:4′,5′-d]pyran-5-yl)methoxy)-2-(4-benzo[d]thiazol-2-ylphenoxyphthalocyaninato] zinc(II) (complex 3) and its linkage to gold nanoparticles (AuNPs) of different shapes through S-Au/N-Au self-assembly. The conjugates of complex 3 (with both gold nanorods (AuNR) and nanospheres (AuNS)), displayed decreased fluorescence quantum yield with corresponding improved triplet and singlet quantum yields compared to complex 3 alone, however 3-AuNR showed improved properties than 3-AuNS. Complex 3 showed relatively low in vitro dark cytotoxicity against the epithelial breast cancer cells with cell survival ≥ 85% at concentration ≤ 160 μg/mL but afforded reduced photodynamic therapy activity which may be due to aggregation. 3-AuNR afforded superior PDT activity with more than 50% viable cells at concentration ≥ 40 μg/mL in comparison to 3-AuNS with more than 50% viable cells at concentration ≥ 80 μg/mL. The superior activity of 3-AuNR is attributed to the photothermal therapy effect since nanorods absorb more light at 680 nm than nanospheres.
- Full Text:
- Date Issued: 2018
- Authors: Dube, Edith , Oluwole, David O , Nwaji, Njemuwa , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/234524 , vital:50205 , xlink:href="https://doi.org/10.1016/j.saa.2018.05.081"
- Description: In this work, we report on the synthesis of tris-[(2,2,7,7-tetramethyltetrahydro-3aH-bis([1,3]dioxolo)[4,5-b:4′,5′-d]pyran-5-yl)methoxy)-2-(4-benzo[d]thiazol-2-ylphenoxyphthalocyaninato] zinc(II) (complex 3) and its linkage to gold nanoparticles (AuNPs) of different shapes through S-Au/N-Au self-assembly. The conjugates of complex 3 (with both gold nanorods (AuNR) and nanospheres (AuNS)), displayed decreased fluorescence quantum yield with corresponding improved triplet and singlet quantum yields compared to complex 3 alone, however 3-AuNR showed improved properties than 3-AuNS. Complex 3 showed relatively low in vitro dark cytotoxicity against the epithelial breast cancer cells with cell survival ≥ 85% at concentration ≤ 160 μg/mL but afforded reduced photodynamic therapy activity which may be due to aggregation. 3-AuNR afforded superior PDT activity with more than 50% viable cells at concentration ≥ 40 μg/mL in comparison to 3-AuNS with more than 50% viable cells at concentration ≥ 80 μg/mL. The superior activity of 3-AuNR is attributed to the photothermal therapy effect since nanorods absorb more light at 680 nm than nanospheres.
- Full Text:
- Date Issued: 2018
Photophysicochemical and photodynamic therapy properties of metallophthalocyanines linked to gold speckled silica nanoparticles
- Dube, Edith, Oluwole, David O, Niemuwa, Nwaji, Prinsloo, Earl, Nyokong, Tebello
- Authors: Dube, Edith , Oluwole, David O , Niemuwa, Nwaji , Prinsloo, Earl , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187472 , vital:44657 , xlink:href="https://doi.org/10.1016/j.pdpdt.2019.01.019"
- Description: This work reports on the linkage of 2(3),9(10),16(17),23(24) tetrakis [(benzo[d]thiazol-2-yl phenoxy) phthalocyaninato] zinc(II) (1) and indium(III) chloride (2) to gold speckled silica (GSS) nanoparticles via gold to sulphur (Au-S) and gold to nitrogen (Au-N) self-assembly to form the conjugates: 1-GSS and 2-GSS. The formed conjugates were characterized using microscopic and spectroscopic techniques, and the photophysicochemical properties and photodynamic therapy (PDT) activity against human breast adenocarcinoma cell line (MCF-7 cells) were studied. The conjugates afforded decrease in fluorescence quantum yields with corresponding increase in triplet and singlet oxygen quantum yields when compared to phthalocyanines alone. Singlet oxygen is cytotoxic to cancer cells hence it is important for PDT. The in vitro dark toxicity of complex 2 and 2-GSS against MCF–7 cells showed ≥93% viable cells within concentration ranges of 10–160 μg/mL. 2–GSS showed enhanced PDT activity with less than 50% viable cells at 80 μg/mL as compared to 2 and GSS alone which showed > 60% viable cells within 10–160 μg/mL. The observed improvements in the PDT activity of 2-GSS could be attributed to the high singlet oxygen generation of 2-GSS compared to 2 alone in addition to the phototoxicity of GSS.
- Full Text:
- Date Issued: 2019
- Authors: Dube, Edith , Oluwole, David O , Niemuwa, Nwaji , Prinsloo, Earl , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187472 , vital:44657 , xlink:href="https://doi.org/10.1016/j.pdpdt.2019.01.019"
- Description: This work reports on the linkage of 2(3),9(10),16(17),23(24) tetrakis [(benzo[d]thiazol-2-yl phenoxy) phthalocyaninato] zinc(II) (1) and indium(III) chloride (2) to gold speckled silica (GSS) nanoparticles via gold to sulphur (Au-S) and gold to nitrogen (Au-N) self-assembly to form the conjugates: 1-GSS and 2-GSS. The formed conjugates were characterized using microscopic and spectroscopic techniques, and the photophysicochemical properties and photodynamic therapy (PDT) activity against human breast adenocarcinoma cell line (MCF-7 cells) were studied. The conjugates afforded decrease in fluorescence quantum yields with corresponding increase in triplet and singlet oxygen quantum yields when compared to phthalocyanines alone. Singlet oxygen is cytotoxic to cancer cells hence it is important for PDT. The in vitro dark toxicity of complex 2 and 2-GSS against MCF–7 cells showed ≥93% viable cells within concentration ranges of 10–160 μg/mL. 2–GSS showed enhanced PDT activity with less than 50% viable cells at 80 μg/mL as compared to 2 and GSS alone which showed > 60% viable cells within 10–160 μg/mL. The observed improvements in the PDT activity of 2-GSS could be attributed to the high singlet oxygen generation of 2-GSS compared to 2 alone in addition to the phototoxicity of GSS.
- Full Text:
- Date Issued: 2019
Photophysicochemical behaviour of phenoxy propanoic acid functionalised zinc phthalocyanines when grafted onto iron oxide and silica nanoparticles: Effects in photodynamic antimicrobial chemotherapy
- Dube, Edith, Soy, Rodath, Shumba, Mumyaradzi, Nyokong, Tebello
- Authors: Dube, Edith , Soy, Rodath , Shumba, Mumyaradzi , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185465 , vital:44389 , xlink:href="https://doi.org/10.1016/j.jlumin.2021.117939"
- Description: This work reports on the covalent linkage of (3-aminopropyl)triethoxysilane (APTES) functionalised iron oxide (IONPs–APTES) and silica (SiNPs–APTES) nanoparticles with zinc(II) tetra–([3–(4–phenoxy) propanoic acid) phthalocyanine] (1) and zinc(II) mono–([3–(4–phenoxy) propanoic acid) phthalocyanine (2) via an amide bond to form the conjugates, 1–IONPs-APTES, 1–SiNPs–APTES, 2-IONPs-APTES and 2-SiNPs-APTES). The photophysicochemical behaviour of the conjugates was investigated. These were characterized by a decrease in the fluorescence quantum yields and lifetimes, and an increase in the triplet quantum yield and singlet oxygen quantum yield when compared to complex 1 and 2 alone. The conjugates to IONPs-APTES displayed higher ΦT than those of SiNPs-APTES probably due to the heavy atom effect of iron compared to silica and the high loading capacity of the relatively smaller iron oxide NPs, however, there was no significant difference in the ΦΔ values of 2-IONPs-APTES (ΦΔ=0.59) and 2-SiNPs-APTES (ΦΔ=0.58), suggesting that the energy transfer process between the excited triplet state of 2-IONPs-APTES and ground state molecular oxygen was not effective. Photodynamic antimicrobial chemotherapy (PACT) studies showed that linkage of Pcs to NPs improves their photoinactivation capability against Staphylococcus aureus and Escherichia coli. IONPs-APTES and its conjugates generally displayed the highest log reductions than SiNPs-APTES and its conjugates except for studies after 75 min of irradiation for S. Aureus where the log reductions are the same. 2-IONP-APTES was recovered using a magnet after each photodegradation cycle and its stability after 3 cycles confirmed re-usability.
- Full Text:
- Date Issued: 2021
- Authors: Dube, Edith , Soy, Rodath , Shumba, Mumyaradzi , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185465 , vital:44389 , xlink:href="https://doi.org/10.1016/j.jlumin.2021.117939"
- Description: This work reports on the covalent linkage of (3-aminopropyl)triethoxysilane (APTES) functionalised iron oxide (IONPs–APTES) and silica (SiNPs–APTES) nanoparticles with zinc(II) tetra–([3–(4–phenoxy) propanoic acid) phthalocyanine] (1) and zinc(II) mono–([3–(4–phenoxy) propanoic acid) phthalocyanine (2) via an amide bond to form the conjugates, 1–IONPs-APTES, 1–SiNPs–APTES, 2-IONPs-APTES and 2-SiNPs-APTES). The photophysicochemical behaviour of the conjugates was investigated. These were characterized by a decrease in the fluorescence quantum yields and lifetimes, and an increase in the triplet quantum yield and singlet oxygen quantum yield when compared to complex 1 and 2 alone. The conjugates to IONPs-APTES displayed higher ΦT than those of SiNPs-APTES probably due to the heavy atom effect of iron compared to silica and the high loading capacity of the relatively smaller iron oxide NPs, however, there was no significant difference in the ΦΔ values of 2-IONPs-APTES (ΦΔ=0.59) and 2-SiNPs-APTES (ΦΔ=0.58), suggesting that the energy transfer process between the excited triplet state of 2-IONPs-APTES and ground state molecular oxygen was not effective. Photodynamic antimicrobial chemotherapy (PACT) studies showed that linkage of Pcs to NPs improves their photoinactivation capability against Staphylococcus aureus and Escherichia coli. IONPs-APTES and its conjugates generally displayed the highest log reductions than SiNPs-APTES and its conjugates except for studies after 75 min of irradiation for S. Aureus where the log reductions are the same. 2-IONP-APTES was recovered using a magnet after each photodegradation cycle and its stability after 3 cycles confirmed re-usability.
- Full Text:
- Date Issued: 2021
Investigation of photophysicochemical properties of zinc phthalocyanines conjugated to metallic nanoparticles
- Dube, Edith, Nwaji, Njemuwa, Oluwole, David O, Mack, John, Nyokong, Tebello
- Authors: Dube, Edith , Nwaji, Njemuwa , Oluwole, David O , Mack, John , Nyokong, Tebello
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/233425 , vital:50089 , xlink:href="https://doi.org/10.1016/j.jphotochem.2017.09.020"
- Description: The syntheses of zinc(II) tetra–[3–(4–phenoxy) (propanoic acid) phthalocyanine] (2) and zinc(II) mono–[3–(4–phenoxy) (propanoic acid) phthalocyanine (3) are reported in this work. Compounds 2 and 3 were covalently linked to glutathione capped silver (AgNPs–GSH), gold (AuNPs–GSH) and silver-gold alloy (Ag3Au1NPs–GSH) nanoparticles (NPs) via an amide bond formation to afford the conjugates: 2–AgNPs–GSH, 3–AgNPs–GSH, 2–AuNPs–GSH, 3–AuNPs–GSH, 2-Ag3Au1NPs–GSH and 3-Ag3Au1NPs–GSH. The photophysicochemical behaviours of the compounds and their conjugates with NPs were assessed in solution. The conjugates afforded a decrease in fluorescence quantum yields and lifetimes with improved triplet quantum yields in comparison to the compounds. Accordingly, the AgNPs and AuNPs conjugates with the compounds afforded high singlet quantum yields. On the contrary, the conjugates of the alloy afforded decreased singlet quantum yields probably due to the screening effect. The compounds and their conjugates with NPs could serve as a viable and efficacious photosensitizer for photodynamic therapy.
- Full Text:
- Date Issued: 2017
- Authors: Dube, Edith , Nwaji, Njemuwa , Oluwole, David O , Mack, John , Nyokong, Tebello
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/233425 , vital:50089 , xlink:href="https://doi.org/10.1016/j.jphotochem.2017.09.020"
- Description: The syntheses of zinc(II) tetra–[3–(4–phenoxy) (propanoic acid) phthalocyanine] (2) and zinc(II) mono–[3–(4–phenoxy) (propanoic acid) phthalocyanine (3) are reported in this work. Compounds 2 and 3 were covalently linked to glutathione capped silver (AgNPs–GSH), gold (AuNPs–GSH) and silver-gold alloy (Ag3Au1NPs–GSH) nanoparticles (NPs) via an amide bond formation to afford the conjugates: 2–AgNPs–GSH, 3–AgNPs–GSH, 2–AuNPs–GSH, 3–AuNPs–GSH, 2-Ag3Au1NPs–GSH and 3-Ag3Au1NPs–GSH. The photophysicochemical behaviours of the compounds and their conjugates with NPs were assessed in solution. The conjugates afforded a decrease in fluorescence quantum yields and lifetimes with improved triplet quantum yields in comparison to the compounds. Accordingly, the AgNPs and AuNPs conjugates with the compounds afforded high singlet quantum yields. On the contrary, the conjugates of the alloy afforded decreased singlet quantum yields probably due to the screening effect. The compounds and their conjugates with NPs could serve as a viable and efficacious photosensitizer for photodynamic therapy.
- Full Text:
- Date Issued: 2017
A gold–chitosan composite with low symmetry zinc phthalocyanine for enhanced singlet oxygen generation and improved photodynamic therapy activity
- Dube, Edith, Oluwole, David O, Prinsloo, Earl, Nyokong, Tebello
- Authors: Dube, Edith , Oluwole, David O , Prinsloo, Earl , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/233397 , vital:50087 , xlink:href="https://doi.org/10.1039/C8NJ00801A"
- Description: Novel zinc(II) 3-(4-((3,17,23-tris(4-(benzo[d]thiazol-2-yl)phenoxy)phthalocyanine-9-yl)oxy)phenyl)propanoic acid (complex 3) was synthesised. Complex 3 was subsequently reacted with gold nanoparticles (AuNPs), chitosan (CT) and a gold–chitosan (AuCT) hybrid to form 3-AuNPs, 3-CT and 3-AuCT, respectively. The conjugates afforded a decrease in fluorescence quantum yield with a corresponding increase in the triplet and singlet quantum yields compared to complex 3. The in vitro dark cytotoxicity and photodynamic therapy activity (PDT) of complex 3 and 3-AuCT composites were investigated against epithelial breast cancer cells (MCF-7) with both the samples showing minimum dark cytotoxicity. They both accounted for a cell viability of ≥90% at a concentration of ≤59.2 μg mL−1. 3-AuCT showed better PDT activity (compared to 3 alone) with less than 50% viable cells at a concentration of ≥29.6 μg mL−1 making it potentially applicable for PDT. On the other hand, AuCT displayed some activity against cancer cells, probably due to photothermal activity since gold is a light absorber, however it had more than 50% viable cells at a concentration of ≤59.2 μg mL−1.
- Full Text:
- Date Issued: 2018
- Authors: Dube, Edith , Oluwole, David O , Prinsloo, Earl , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/233397 , vital:50087 , xlink:href="https://doi.org/10.1039/C8NJ00801A"
- Description: Novel zinc(II) 3-(4-((3,17,23-tris(4-(benzo[d]thiazol-2-yl)phenoxy)phthalocyanine-9-yl)oxy)phenyl)propanoic acid (complex 3) was synthesised. Complex 3 was subsequently reacted with gold nanoparticles (AuNPs), chitosan (CT) and a gold–chitosan (AuCT) hybrid to form 3-AuNPs, 3-CT and 3-AuCT, respectively. The conjugates afforded a decrease in fluorescence quantum yield with a corresponding increase in the triplet and singlet quantum yields compared to complex 3. The in vitro dark cytotoxicity and photodynamic therapy activity (PDT) of complex 3 and 3-AuCT composites were investigated against epithelial breast cancer cells (MCF-7) with both the samples showing minimum dark cytotoxicity. They both accounted for a cell viability of ≥90% at a concentration of ≤59.2 μg mL−1. 3-AuCT showed better PDT activity (compared to 3 alone) with less than 50% viable cells at a concentration of ≥29.6 μg mL−1 making it potentially applicable for PDT. On the other hand, AuCT displayed some activity against cancer cells, probably due to photothermal activity since gold is a light absorber, however it had more than 50% viable cells at a concentration of ≤59.2 μg mL−1.
- Full Text:
- Date Issued: 2018
Effect of gold nanoparticles shape and size on the photophysicochemical behaviour of symmetric and asymmetric zinc phthalocyanines
- Dube, Edith, Nyokong, Tebello
- Authors: Dube, Edith , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187569 , vital:44672 , xlink:href="https://doi.org/10.1016/j.jlumin.2018.09.063"
- Description: Glutathione (GSH) capped Au nanotriangles (AuNTs–GSH) and nanospheres (AuNSs–GSH) are covalently linked to symmetric Zn phthalocyanine (ZnPc) substituted with phenoxy propanoic acid substituents only (complex 1) and two asymmetric ZnPc, each containing one phenoxy propanoic acid and three benzothiazole phenoxy moieties (complex 2), and one phenoxy propanoic acid and no other ligands (complex 3). The photophysicochemical behaviour of Pc complexes and their conjugates were studied. All conjugates displayed improved triplet and singlet oxygen quantum yields with decreases in fluorescence quantum yields compared to their respective Pc complexes. The conjugates of asymmetric complexes 2 and 3, afforded much higher triplet and singlet oxygen quantum yields compared to the symmetric complex 1, and could serve as good candidates for photodynamic therapy
- Full Text:
- Date Issued: 2019
- Authors: Dube, Edith , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187569 , vital:44672 , xlink:href="https://doi.org/10.1016/j.jlumin.2018.09.063"
- Description: Glutathione (GSH) capped Au nanotriangles (AuNTs–GSH) and nanospheres (AuNSs–GSH) are covalently linked to symmetric Zn phthalocyanine (ZnPc) substituted with phenoxy propanoic acid substituents only (complex 1) and two asymmetric ZnPc, each containing one phenoxy propanoic acid and three benzothiazole phenoxy moieties (complex 2), and one phenoxy propanoic acid and no other ligands (complex 3). The photophysicochemical behaviour of Pc complexes and their conjugates were studied. All conjugates displayed improved triplet and singlet oxygen quantum yields with decreases in fluorescence quantum yields compared to their respective Pc complexes. The conjugates of asymmetric complexes 2 and 3, afforded much higher triplet and singlet oxygen quantum yields compared to the symmetric complex 1, and could serve as good candidates for photodynamic therapy
- Full Text:
- Date Issued: 2019
Photophysicochemical behaviour of anionic indium phthalocyanine when grafted onto AgxAuy and porous silica nanoparticles
- Dube, Edith, Oluwole, David O, Nyokong, Tebello
- Authors: Dube, Edith , Oluwole, David O , Nyokong, Tebello
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188899 , vital:44796 , xlink:href="https://doi.org/10.1016/j.jlumin.2017.05.071"
- Description: This work reports on the synthesis of glutathione functionalised Ag3Au1 (Ag rich alloy, denoted as AgAu) and Ag1Au3 (Au rich alloy – denoted as AuAg) nano alloys as well as aminopropyl triethoxylsilane capped Ag1Au3 doped silica nanoparticles (NPs). The NPs were covalently linked to indium(III) chloride 2,9(10),16(17),23(24)–tetra–(3–carboxyphenoxy)phthalocyanine (1) via amide bond to form 1–AgAuNPs–GSH and 1–AuAgNPs–GSH. The AgAuNPs were also doped into aminopropyl triethoxylsilane (APTES) silica NPs (SiNPs-APTES) followed by linkage to complex 1 to form 1–AgAu-SiNPs–APTES. The photophysicochemical behaviour of complex 1 and its nanoconjugates were investigated. Decrease in the fluorescence quantum yields and lifetimes was observed in the conjugates in comparison to 1 alone. The singlet oxygen quantum yield for 1–AgAuNPs–GSH and 1–AuAgNPs–GSH decreased probably due to the screening effect caused by the NPs, while that of 1–AgAu-SiNPs–APTES increased in dimethylsulfoxide probably due to the permeability of the porous silica matrix to molecular oxygen.
- Full Text:
- Date Issued: 2017
- Authors: Dube, Edith , Oluwole, David O , Nyokong, Tebello
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188899 , vital:44796 , xlink:href="https://doi.org/10.1016/j.jlumin.2017.05.071"
- Description: This work reports on the synthesis of glutathione functionalised Ag3Au1 (Ag rich alloy, denoted as AgAu) and Ag1Au3 (Au rich alloy – denoted as AuAg) nano alloys as well as aminopropyl triethoxylsilane capped Ag1Au3 doped silica nanoparticles (NPs). The NPs were covalently linked to indium(III) chloride 2,9(10),16(17),23(24)–tetra–(3–carboxyphenoxy)phthalocyanine (1) via amide bond to form 1–AgAuNPs–GSH and 1–AuAgNPs–GSH. The AgAuNPs were also doped into aminopropyl triethoxylsilane (APTES) silica NPs (SiNPs-APTES) followed by linkage to complex 1 to form 1–AgAu-SiNPs–APTES. The photophysicochemical behaviour of complex 1 and its nanoconjugates were investigated. Decrease in the fluorescence quantum yields and lifetimes was observed in the conjugates in comparison to 1 alone. The singlet oxygen quantum yield for 1–AgAuNPs–GSH and 1–AuAgNPs–GSH decreased probably due to the screening effect caused by the NPs, while that of 1–AgAu-SiNPs–APTES increased in dimethylsulfoxide probably due to the permeability of the porous silica matrix to molecular oxygen.
- Full Text:
- Date Issued: 2017
Effect of gold nanoparticle shape on the photophysicochemical properties of sulphur containing metallophthalocyanines
- Dube, Edith, Nyokong, Tebello
- Authors: Dube, Edith , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187048 , vital:44559 , xlink:href="https://doi.org/10.1016/j.molstruc.2018.12.091"
- Description: In this work tetrakise[(thiopheneethoxy) phthalocyaninato] zinc(II) (1), tetrakise[(thiopheneethoxy) phthalocyaninato] indium (II) chloride (2), tetrakis [(benzo [d]thiazol-2-yl phenoxy) phthalocyaninato] zinc(II) (3), and tetrakis [(benzo [d]thiazol-2-yl phenoxy)phthalocyaninato] indium (II) chloride (4) were linked to both gold nanospheres (AuNSs) and gold nanotriangles (AuNTs) via Au-S and Au-N (the latter for complexes 3 and 4 only) self assembly. The photophysicochemical behaviour of complexes and their conjugates were studied. The conjugates yielded improved triplet and singlet quantum yields, with nanospheres displaying better properties than nanotriangles. The conjugates with a benzothiazole phenoxy substituent also yielded better properties than their thiophene ethoxy counterpart. These conjugates especially those with a benzothiazole phenoxy substituent have potential as photosensitisers for photodynamic therapy applications.
- Full Text:
- Date Issued: 2019
- Authors: Dube, Edith , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187048 , vital:44559 , xlink:href="https://doi.org/10.1016/j.molstruc.2018.12.091"
- Description: In this work tetrakise[(thiopheneethoxy) phthalocyaninato] zinc(II) (1), tetrakise[(thiopheneethoxy) phthalocyaninato] indium (II) chloride (2), tetrakis [(benzo [d]thiazol-2-yl phenoxy) phthalocyaninato] zinc(II) (3), and tetrakis [(benzo [d]thiazol-2-yl phenoxy)phthalocyaninato] indium (II) chloride (4) were linked to both gold nanospheres (AuNSs) and gold nanotriangles (AuNTs) via Au-S and Au-N (the latter for complexes 3 and 4 only) self assembly. The photophysicochemical behaviour of complexes and their conjugates were studied. The conjugates yielded improved triplet and singlet quantum yields, with nanospheres displaying better properties than nanotriangles. The conjugates with a benzothiazole phenoxy substituent also yielded better properties than their thiophene ethoxy counterpart. These conjugates especially those with a benzothiazole phenoxy substituent have potential as photosensitisers for photodynamic therapy applications.
- Full Text:
- Date Issued: 2019
The photophysicochemical behavior of symmetric and asymmetric zinc phthalocyanines, surface assembled onto gold nanotriangles
- Dube, Edith, Nwaji, Njemuwa, Mack, John, Nyokong, Tebello
- Authors: Dube, Edith , Nwaji, Njemuwa , Mack, John , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/233310 , vital:50079 , xlink:href="https://doi.org/10.1039/C8NJ02746C"
- Description: The synthesis of a novel asymmetric phthalocyanine, (4-(4-(benzo[d]thiazol-2-yl)phenoxy)-2,10,17-tris(4-(2-carboxyethyl)phenoxy)phthalocyaninatol)zinc(II), complex 3, is reported. Complex 3 together with the previously reported complexes tetrakis[(benzo[d]thiazol-2-yl phenoxy)phthalocyaninato]zinc(II) (4) and 3-(4-((3,17,23-tris(4-(benzo[d]thiazol-2-yl)phenoxy)phthalocyaninatol)oxy)phenyl)propanoic acid zinc(II) (5), were linked to gold nanotriangles (AuNTs) through S–Au/Au–N self-assembly to afford the conjugates (3-AuNTs, 4-AuNTs and 5-AuNTs). The photophysicochemical behaviour of the complexes and their conjugates were studied. The asymmetric complexes 3 and 5, displayed improved triplet and singlet oxygen quantum yields compared to the symmetric complex 4, while all conjugates displayed improved triplet and singlet oxygen quantum yields compared to their respective complexes alone. The complexes and their conjugates could serve as good candidates for photodynamic therapy.
- Full Text:
- Date Issued: 2018
- Authors: Dube, Edith , Nwaji, Njemuwa , Mack, John , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/233310 , vital:50079 , xlink:href="https://doi.org/10.1039/C8NJ02746C"
- Description: The synthesis of a novel asymmetric phthalocyanine, (4-(4-(benzo[d]thiazol-2-yl)phenoxy)-2,10,17-tris(4-(2-carboxyethyl)phenoxy)phthalocyaninatol)zinc(II), complex 3, is reported. Complex 3 together with the previously reported complexes tetrakis[(benzo[d]thiazol-2-yl phenoxy)phthalocyaninato]zinc(II) (4) and 3-(4-((3,17,23-tris(4-(benzo[d]thiazol-2-yl)phenoxy)phthalocyaninatol)oxy)phenyl)propanoic acid zinc(II) (5), were linked to gold nanotriangles (AuNTs) through S–Au/Au–N self-assembly to afford the conjugates (3-AuNTs, 4-AuNTs and 5-AuNTs). The photophysicochemical behaviour of the complexes and their conjugates were studied. The asymmetric complexes 3 and 5, displayed improved triplet and singlet oxygen quantum yields compared to the symmetric complex 4, while all conjugates displayed improved triplet and singlet oxygen quantum yields compared to their respective complexes alone. The complexes and their conjugates could serve as good candidates for photodynamic therapy.
- Full Text:
- Date Issued: 2018
Synthetic pathways to water-soluble phthalocyanines and close analogs
- Dumoulin, Fabienne, Durmus, Mahmut, Ahsen, Vefa, Nyokong, Tebello
- Authors: Dumoulin, Fabienne , Durmus, Mahmut , Ahsen, Vefa , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/249082 , vital:51776 , xlink:href="https://doi.org/10.1016/j.ccr.2010.05.002"
- Description: The different types of water-soluble phthalocyanines are presented and their synthesis is reviewed.
- Full Text:
- Date Issued: 2010
- Authors: Dumoulin, Fabienne , Durmus, Mahmut , Ahsen, Vefa , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/249082 , vital:51776 , xlink:href="https://doi.org/10.1016/j.ccr.2010.05.002"
- Description: The different types of water-soluble phthalocyanines are presented and their synthesis is reviewed.
- Full Text:
- Date Issued: 2010
Photophysical and photochemical studies of long chain-substituted zinc phthalocyanines
- Durmus, Mahmut, Ahsen, Vefa, Nyokong, Tebello
- Authors: Durmus, Mahmut , Ahsen, Vefa , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281310 , vital:55711 , xlink:href="https://doi.org/10.1016/j.jphotochem.2006.08.025"
- Description: Photochemical and photophysical measurements were conducted on peripheral and non-peripheral tetra(13,17-dioxanonacosane-15-hydroxy)-substituted zinc phthalocyanines (1, 2). General trends are described for quantum yields of photodegradation, fluorescence yields, triplet lifetimes and triplet quantum yields as well as singlet quantum yields of these compounds in dimethylformamide (DMF) and toluene. The effects of the solvents on the photophysical and photochemical parameters of the zinc(II) phthalocyanines (1, 2) are reported.
- Full Text:
- Date Issued: 2007
- Authors: Durmus, Mahmut , Ahsen, Vefa , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281310 , vital:55711 , xlink:href="https://doi.org/10.1016/j.jphotochem.2006.08.025"
- Description: Photochemical and photophysical measurements were conducted on peripheral and non-peripheral tetra(13,17-dioxanonacosane-15-hydroxy)-substituted zinc phthalocyanines (1, 2). General trends are described for quantum yields of photodegradation, fluorescence yields, triplet lifetimes and triplet quantum yields as well as singlet quantum yields of these compounds in dimethylformamide (DMF) and toluene. The effects of the solvents on the photophysical and photochemical parameters of the zinc(II) phthalocyanines (1, 2) are reported.
- Full Text:
- Date Issued: 2007
Synthesis and solvent effects on the electronic absorption and fluorescence spectral properties of substituted zinc phthalocyanines
- Durmus, Mahmut, Nyokong, Tebello
- Authors: Durmus, Mahmut , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293279 , vital:57071 , xlink:href="https://doi.org/10.1016/j.poly.2007.01.018"
- Description: The synthesis and spectroscopic properties of the following tetra- and octa-substituted aryloxy zinc(II) phthalocyanines are reported for the first time: 1,(4)-(tetrabenzyloxyphenoxyphthalocyaninato) zinc(II) (7); 2,(3)-(tetrabenzyloxyphenoxyphthalocyaninato) zinc(II) (8); 2,3-(octabenzyloxyphenoxyphthalocyaninato) zinc(II) (9). The new compounds have been characterized by elemental analysis, IR, 1H NMR spectroscopy and electronic spectroscopy. Spectroscopic properties of these compounds were investigated in different solvents. Protonation of non-peripherally substituted complex 7 resulted in the splitting and red-shifting of the Q-band. The peripherally substituted derivatives 8 and 9, did not show the split in the Q-band. Fluorescence spectra of the derivatives show Stokes shifts typical of MPc complexes.
- Full Text:
- Date Issued: 2007
- Authors: Durmus, Mahmut , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293279 , vital:57071 , xlink:href="https://doi.org/10.1016/j.poly.2007.01.018"
- Description: The synthesis and spectroscopic properties of the following tetra- and octa-substituted aryloxy zinc(II) phthalocyanines are reported for the first time: 1,(4)-(tetrabenzyloxyphenoxyphthalocyaninato) zinc(II) (7); 2,(3)-(tetrabenzyloxyphenoxyphthalocyaninato) zinc(II) (8); 2,3-(octabenzyloxyphenoxyphthalocyaninato) zinc(II) (9). The new compounds have been characterized by elemental analysis, IR, 1H NMR spectroscopy and electronic spectroscopy. Spectroscopic properties of these compounds were investigated in different solvents. Protonation of non-peripherally substituted complex 7 resulted in the splitting and red-shifting of the Q-band. The peripherally substituted derivatives 8 and 9, did not show the split in the Q-band. Fluorescence spectra of the derivatives show Stokes shifts typical of MPc complexes.
- Full Text:
- Date Issued: 2007
Energy transfer in zinc porphyrin–phthalocyanine heterotrimer and heterononamer studied by fluorescence resonance energy transfer (FRET)
- Durmus, Mahmut, Chen, Jiyao Y, Zhao, Zhixin X, Nyokong, Tebello
- Authors: Durmus, Mahmut , Chen, Jiyao Y , Zhao, Zhixin X , Nyokong, Tebello
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/268599 , vital:54213 , xlink:href="https://doi.org/10.1016/j.saa.2007.07.010"
- Description: Two or eight zinc triphenyl porphyrins were conjugated with Zn-phthalocyanine or H2-phthalocyanine to form ZnPc–(ZnTPP)2, ZnPc–(ZnTPP)8, H2Pc–(ZnTPP)2 and H2Pc–(ZnTPP)8. Energy transfers from the porphyrin moiety to phthalocyanine part were quantitatively studied with the modality of fluorescence resonance energy transfer (FRET). By measuring the fluorescence increment from the phthalocyanine moiety and the decrease from porphyrin part under selective excitation at the B band of the porphyrin part in those conjugated compounds and their equimolar mixture of compositions, energy transfer efficiencies were estimated to be 90% for H2Pc–(ZnTPP)8 and ZnPc–(ZnTPP)8, and 60%, 30% for ZnPc–(ZnTPP)2 and H2Pc–(ZnTPP)2, respectively.
- Full Text:
- Date Issued: 2008
- Authors: Durmus, Mahmut , Chen, Jiyao Y , Zhao, Zhixin X , Nyokong, Tebello
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/268599 , vital:54213 , xlink:href="https://doi.org/10.1016/j.saa.2007.07.010"
- Description: Two or eight zinc triphenyl porphyrins were conjugated with Zn-phthalocyanine or H2-phthalocyanine to form ZnPc–(ZnTPP)2, ZnPc–(ZnTPP)8, H2Pc–(ZnTPP)2 and H2Pc–(ZnTPP)8. Energy transfers from the porphyrin moiety to phthalocyanine part were quantitatively studied with the modality of fluorescence resonance energy transfer (FRET). By measuring the fluorescence increment from the phthalocyanine moiety and the decrease from porphyrin part under selective excitation at the B band of the porphyrin part in those conjugated compounds and their equimolar mixture of compositions, energy transfer efficiencies were estimated to be 90% for H2Pc–(ZnTPP)8 and ZnPc–(ZnTPP)8, and 60%, 30% for ZnPc–(ZnTPP)2 and H2Pc–(ZnTPP)2, respectively.
- Full Text:
- Date Issued: 2008
The synthesis and photophysicochemical behaviour of novel water-soluble cationic indium (III) phthalocyanine
- Durmus, Mahmut, Erdoğmuş, Ali, Ogunsipe, Abimbola, Nyokong, Tebello
- Authors: Durmus, Mahmut , Erdoğmuş, Ali , Ogunsipe, Abimbola , Nyokong, Tebello
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/263419 , vital:53626 , xlink:href="https://doi.org/10.1016/j.dyepig.2009.01.008"
- Description: The syntheses and characterization of 2,3-octakis-(3-pyridyloxyphthalocyaninato) indium(III) and quaternized 2,3-octakis-(3-pyridyloxyphthalocyaninato) indium(III) are described. The ground state electronic absorption spectra, photophysics and photochemistry of both dyes in DMSO as well as that of the quaternized compound in aqueous solution are also presented. A comparison of the photophysical and photochemical parameters of the two dyes revealed that quaternized 2,3-octakis-(3-pyridyloxyphthalocyaninato) indium(III) was a better photosensitizer than its unquaternized counterpart. The quantum yield values of fluorescence (ΦF), triplet state formation (ΦT) and singlet oxygen formation (ΦΔ) for the cationic dye were found to be 0.03, 0.68 and 0.66 respectively in DMSO; these values were higher than those for 2,3-octakis-(3-pyridyloxyphthalocyaninato) indium(III), which exhibited values of 0.02, 0.66 and 0.63, respectively in DMSO. The values for the cationic dye in aq. solution were 0.02, 0.59 and 0.56 respectively, suggesting that the water-soluble quaternized 2,3-octakis-(3-pyridyloxyphthalocyaninato) indium(III) offers potential as a photosensitizer in photodynamic therapy treatment.
- Full Text:
- Date Issued: 2009
- Authors: Durmus, Mahmut , Erdoğmuş, Ali , Ogunsipe, Abimbola , Nyokong, Tebello
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/263419 , vital:53626 , xlink:href="https://doi.org/10.1016/j.dyepig.2009.01.008"
- Description: The syntheses and characterization of 2,3-octakis-(3-pyridyloxyphthalocyaninato) indium(III) and quaternized 2,3-octakis-(3-pyridyloxyphthalocyaninato) indium(III) are described. The ground state electronic absorption spectra, photophysics and photochemistry of both dyes in DMSO as well as that of the quaternized compound in aqueous solution are also presented. A comparison of the photophysical and photochemical parameters of the two dyes revealed that quaternized 2,3-octakis-(3-pyridyloxyphthalocyaninato) indium(III) was a better photosensitizer than its unquaternized counterpart. The quantum yield values of fluorescence (ΦF), triplet state formation (ΦT) and singlet oxygen formation (ΦΔ) for the cationic dye were found to be 0.03, 0.68 and 0.66 respectively in DMSO; these values were higher than those for 2,3-octakis-(3-pyridyloxyphthalocyaninato) indium(III), which exhibited values of 0.02, 0.66 and 0.63, respectively in DMSO. The values for the cationic dye in aq. solution were 0.02, 0.59 and 0.56 respectively, suggesting that the water-soluble quaternized 2,3-octakis-(3-pyridyloxyphthalocyaninato) indium(III) offers potential as a photosensitizer in photodynamic therapy treatment.
- Full Text:
- Date Issued: 2009
The synthesis, fluorescence behaviour and singlet oxygen studies of new water-soluble cationic gallium (III) phthalocyanines
- Durmus, Mahmut, Nyokong, Tebello
- Authors: Durmus, Mahmut , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/280207 , vital:55586 , xlink:href="https://doi.org/10.1016/j.inoche.2006.11.012"
- Description: The preparation of cationic water-soluble gallium phthalocyanine derivatives are described for the first time. Peripheral and non-peripheral 3-hydroxypyridine tetrasubstituted gallium(III)phthalocyanines (5a, 6a) and their quaternarized derivatives (5b and 6b) have been synthesized and characterized by elemental analysis, IR, 1H NMR spectroscopy, electronic spectroscopy and mass spectra. The quaternarized compounds (5b and 6b) are soluble in water and not aggregated (in water and in organic solvents) within a wide concentration range. General trends are described for singlet oxygen quantum yields, fluorescence quantum yields and fluorescence lifetimes of these compounds. These complexes showed better singlet oxygen quantum yields in water than the related quarternarized porphyrazine complexes.
- Full Text:
- Date Issued: 2007
- Authors: Durmus, Mahmut , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/280207 , vital:55586 , xlink:href="https://doi.org/10.1016/j.inoche.2006.11.012"
- Description: The preparation of cationic water-soluble gallium phthalocyanine derivatives are described for the first time. Peripheral and non-peripheral 3-hydroxypyridine tetrasubstituted gallium(III)phthalocyanines (5a, 6a) and their quaternarized derivatives (5b and 6b) have been synthesized and characterized by elemental analysis, IR, 1H NMR spectroscopy, electronic spectroscopy and mass spectra. The quaternarized compounds (5b and 6b) are soluble in water and not aggregated (in water and in organic solvents) within a wide concentration range. General trends are described for singlet oxygen quantum yields, fluorescence quantum yields and fluorescence lifetimes of these compounds. These complexes showed better singlet oxygen quantum yields in water than the related quarternarized porphyrazine complexes.
- Full Text:
- Date Issued: 2007
Synthesis and solvent effects on the electronic absorption and fluorescence spectral properties of substituted zinc phthalocyanines
- Durmus, Mahmut, Nyokong, Tebello
- Authors: Durmus, Mahmut , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283140 , vital:55914 , xlink:href="https://doi.org/10.1016/j.poly.2007.01.018"
- Description: The synthesis and spectroscopic properties of the following tetra- and octa-substituted aryloxy zinc(II) phthalocyanines are reported for the first time: 1,(4)-(tetrabenzyloxyphenoxyphthalocyaninato) zinc(II) (7); 2,(3)-(tetrabenzyloxyphenoxyphthalocyaninato) zinc(II) (8); 2,3-(octabenzyloxyphenoxyphthalocyaninato) zinc(II) (9). The new compounds have been characterized by elemental analysis, IR, 1H NMR spectroscopy and electronic spectroscopy. Spectroscopic properties of these compounds were investigated in different solvents. Protonation of non-peripherally substituted complex 7 resulted in the splitting and red-shifting of the Q-band. The peripherally substituted derivatives 8 and 9, did not show the split in the Q-band. Fluorescence spectra of the derivatives show Stokes shifts typical of MPc complexes.
- Full Text:
- Date Issued: 2007
- Authors: Durmus, Mahmut , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283140 , vital:55914 , xlink:href="https://doi.org/10.1016/j.poly.2007.01.018"
- Description: The synthesis and spectroscopic properties of the following tetra- and octa-substituted aryloxy zinc(II) phthalocyanines are reported for the first time: 1,(4)-(tetrabenzyloxyphenoxyphthalocyaninato) zinc(II) (7); 2,(3)-(tetrabenzyloxyphenoxyphthalocyaninato) zinc(II) (8); 2,3-(octabenzyloxyphenoxyphthalocyaninato) zinc(II) (9). The new compounds have been characterized by elemental analysis, IR, 1H NMR spectroscopy and electronic spectroscopy. Spectroscopic properties of these compounds were investigated in different solvents. Protonation of non-peripherally substituted complex 7 resulted in the splitting and red-shifting of the Q-band. The peripherally substituted derivatives 8 and 9, did not show the split in the Q-band. Fluorescence spectra of the derivatives show Stokes shifts typical of MPc complexes.
- Full Text:
- Date Issued: 2007
Synthesis, photophysical and photochemical properties of aryloxy tetra-substituted gallium and indium phthalocyanine derivatives
- Durmus, Mahmut, Nyokong, Tebello
- Authors: Durmus, Mahmut , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281431 , vital:55724 , xlink:href="https://doi.org/10.1016/j.tet.2006.11.089"
- Description: The synthesis, photophysical and photochemical properties of the tetra-substituted aryloxy gallium(III) and indium(III) phthalocyanines are reported for the first time. General trends are described for photodegradation, singlet oxygen, fluorescence, and triplet quantum yields and triplet lifetimes of these compounds. The introduction of phenoxy and tert-butylphenoxy substituents on the ring resulted in lowering of fluorescence quantum yields and lifetimes, and triplet quantum yields, and an increase of kIC, kISC, and kF. Photoreduction of the complexes was observed during laser flash photolysis. The singlet oxygen quantum yields (ΦΔ), which give an indication of the potential of the complexes as photosensitizers in applications where singlet oxygen is required (Type II mechanism) ranged from 0.41 to 0.91. Thus, these complexes show potential as Type II photosensitizers.
- Full Text:
- Date Issued: 2007
- Authors: Durmus, Mahmut , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281431 , vital:55724 , xlink:href="https://doi.org/10.1016/j.tet.2006.11.089"
- Description: The synthesis, photophysical and photochemical properties of the tetra-substituted aryloxy gallium(III) and indium(III) phthalocyanines are reported for the first time. General trends are described for photodegradation, singlet oxygen, fluorescence, and triplet quantum yields and triplet lifetimes of these compounds. The introduction of phenoxy and tert-butylphenoxy substituents on the ring resulted in lowering of fluorescence quantum yields and lifetimes, and triplet quantum yields, and an increase of kIC, kISC, and kF. Photoreduction of the complexes was observed during laser flash photolysis. The singlet oxygen quantum yields (ΦΔ), which give an indication of the potential of the complexes as photosensitizers in applications where singlet oxygen is required (Type II mechanism) ranged from 0.41 to 0.91. Thus, these complexes show potential as Type II photosensitizers.
- Full Text:
- Date Issued: 2007
Synthesis, photophysical and photochemical studies of new water-soluble indium (III) phthalocyanines
- Durmus, Mahmut, Nyokong, Tebello
- Authors: Durmus, Mahmut , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283976 , vital:56007 , xlink:href="https://doi.org/10.1039/b618478b"
- Description: The preparation of water-soluble indium(III)phthalocyanine complexes is described for the first time in this study. Peripherally and non-peripherally 3-hydroxypyridine tetrasubstituted indium(III) phthalocyanines (5a, 6a) and their quaternarized derivatives (5b, 6b) have been synthesized and characterized by elemental analysis, IR, 1H NMR spectroscopy, electronic spectroscopy and mass spectra. The quaternarized compounds (5b, 6b) show excellent solubility in water, which makes them potential photosensitizers for use in photodynamic therapy (PDT) applications. Photochemical and photophysical measurements were conducted on 3-pyridyloxy appended indium(III) phthalocyanines in dimethylsulfoxide (DMSO) for non-ionic (5b, 6b) derivatives. General trends are described for quantum yields of photodegradation, fluorescence lifetimes, fluorescence quantum yields, triplet lifetimes and triplet quantum yields as well as singlet oxygen quantum yields of these compounds. The singlet oxygen quantum yields (ΦΔ), which give an indication of the potential of the complexes as photosensitizers in applications where singlet oxygen is required (Type II mechanism) are very high (ΦΔ > 0.55). Thus, these complexes may be useful as Type II photosensitizers.
- Full Text:
- Date Issued: 2007
Synthesis, photophysical and photochemical studies of new water-soluble indium (III) phthalocyanines
- Authors: Durmus, Mahmut , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283976 , vital:56007 , xlink:href="https://doi.org/10.1039/b618478b"
- Description: The preparation of water-soluble indium(III)phthalocyanine complexes is described for the first time in this study. Peripherally and non-peripherally 3-hydroxypyridine tetrasubstituted indium(III) phthalocyanines (5a, 6a) and their quaternarized derivatives (5b, 6b) have been synthesized and characterized by elemental analysis, IR, 1H NMR spectroscopy, electronic spectroscopy and mass spectra. The quaternarized compounds (5b, 6b) show excellent solubility in water, which makes them potential photosensitizers for use in photodynamic therapy (PDT) applications. Photochemical and photophysical measurements were conducted on 3-pyridyloxy appended indium(III) phthalocyanines in dimethylsulfoxide (DMSO) for non-ionic (5b, 6b) derivatives. General trends are described for quantum yields of photodegradation, fluorescence lifetimes, fluorescence quantum yields, triplet lifetimes and triplet quantum yields as well as singlet oxygen quantum yields of these compounds. The singlet oxygen quantum yields (ΦΔ), which give an indication of the potential of the complexes as photosensitizers in applications where singlet oxygen is required (Type II mechanism) are very high (ΦΔ > 0.55). Thus, these complexes may be useful as Type II photosensitizers.
- Full Text:
- Date Issued: 2007
Synthesis, photophysical and photochemical properties of tetra-and octa-substituted gallium and indium phthalocyanines
- Durmus, Mahmut, Nyokong, Tebello
- Authors: Durmus, Mahmut , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/271276 , vital:54529 , xlink:href="https://doi.org/10.1016/j.poly.2007.03.007"
- Description: The synthesis, photophysical and photochemical properties of the tetra- and octa-[4-(benzyloxyphenoxy)] substituted gallium(III) and indium(III) phthalocyanines are reported for the first time. The new compounds have been characterized by elemental analysis, IR, 1H NMR spectroscopy and electronic spectroscopy. General trends are described for quantum yields of photodegredation, fluorescence quantum yields and lifetimes, triplet lifetimes and triplet quantum yields as well as singlet oxygen quantum yields of these compounds in dimethylsulfoxide (DMSO). Substituted indium phthalocyanine complexes (7b–9b) showed much higher quantum yields of triplet state and shorter triplet lifetimes, compared to the substituted GaPc derivatives due to enhanced intersystem crossing (ISC) in the former. The gallium and indium phthalocyanine complexes showed phototransformation during laser irradiation due to ring reduction. The singlet oxygen quantum yields (ΦΔ), which give an indication of the potential of the complexes as photosensitizers in applications where singlet oxygen is required (Type II mechanism) ranged from 0.51 to 0.94. Thus, these complexes show potential as photodynamic therapy of cancer.
- Full Text:
- Date Issued: 2007
- Authors: Durmus, Mahmut , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/271276 , vital:54529 , xlink:href="https://doi.org/10.1016/j.poly.2007.03.007"
- Description: The synthesis, photophysical and photochemical properties of the tetra- and octa-[4-(benzyloxyphenoxy)] substituted gallium(III) and indium(III) phthalocyanines are reported for the first time. The new compounds have been characterized by elemental analysis, IR, 1H NMR spectroscopy and electronic spectroscopy. General trends are described for quantum yields of photodegredation, fluorescence quantum yields and lifetimes, triplet lifetimes and triplet quantum yields as well as singlet oxygen quantum yields of these compounds in dimethylsulfoxide (DMSO). Substituted indium phthalocyanine complexes (7b–9b) showed much higher quantum yields of triplet state and shorter triplet lifetimes, compared to the substituted GaPc derivatives due to enhanced intersystem crossing (ISC) in the former. The gallium and indium phthalocyanine complexes showed phototransformation during laser irradiation due to ring reduction. The singlet oxygen quantum yields (ΦΔ), which give an indication of the potential of the complexes as photosensitizers in applications where singlet oxygen is required (Type II mechanism) ranged from 0.51 to 0.94. Thus, these complexes show potential as photodynamic therapy of cancer.
- Full Text:
- Date Issued: 2007