Spectral, photophysical and photochemical properties of tetra-and octaglycosylated zinc phthalocyanines
- Iqbal, Zafar, Masilela, Nkosiphile, Nyokong, Tebello, Lyubimtsev, Alexey, Hanack, Michael, Ziegler, Thomas
- Authors: Iqbal, Zafar , Masilela, Nkosiphile , Nyokong, Tebello , Lyubimtsev, Alexey , Hanack, Michael , Ziegler, Thomas
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244428 , vital:51256 , xlink:href="https://doi.org/10.1039/c2pp05348a"
- Description: Photophysical and photochemical properties of a series of tetra- and octaglycosylated zinc phthalocyanines (ZnPcs) substituted with glucose and galactose moieties have been reported. Spectral properties of these phthalocyanines are compared in DMSO. Absorption spectra of the non-peripherally tetra-substituted ZnPcs 2 showed a significant red shift in their Q-band maxima as compared to the peripherally substituted analog 1. All the complexes gave high triplet quantum yields ranging from 0.68 to 0.88, whereas triplet lifetimes were in the range of 100–430 µs in argon-saturated solutions. The octagalactosylated ZnPc 3b showed the highest triplet quantum yield and singlet oxygen quantum yield of 0.88 and 0.69, respectively. The fluorescence quantum yields and lifetimes of all the compounds under investigation were within the range of zinc phthalocyanine complexes.
- Full Text:
- Date Issued: 2012
- Authors: Iqbal, Zafar , Masilela, Nkosiphile , Nyokong, Tebello , Lyubimtsev, Alexey , Hanack, Michael , Ziegler, Thomas
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244428 , vital:51256 , xlink:href="https://doi.org/10.1039/c2pp05348a"
- Description: Photophysical and photochemical properties of a series of tetra- and octaglycosylated zinc phthalocyanines (ZnPcs) substituted with glucose and galactose moieties have been reported. Spectral properties of these phthalocyanines are compared in DMSO. Absorption spectra of the non-peripherally tetra-substituted ZnPcs 2 showed a significant red shift in their Q-band maxima as compared to the peripherally substituted analog 1. All the complexes gave high triplet quantum yields ranging from 0.68 to 0.88, whereas triplet lifetimes were in the range of 100–430 µs in argon-saturated solutions. The octagalactosylated ZnPc 3b showed the highest triplet quantum yield and singlet oxygen quantum yield of 0.88 and 0.69, respectively. The fluorescence quantum yields and lifetimes of all the compounds under investigation were within the range of zinc phthalocyanine complexes.
- Full Text:
- Date Issued: 2012
Synthesis and photophysicochemical properties of novel zinc phthalocyanines mono substituted with carboxyl containing functional groups
- Rapulenyane, Nomasonto, Antunes, Edith M, Masilela, Nkosiphile, Nyokong, Tebello
- Authors: Rapulenyane, Nomasonto , Antunes, Edith M , Masilela, Nkosiphile , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/242389 , vital:51037 , xlink:href="https://doi.org/10.1016/j.jphotochem.2012.09.007"
- Description: This work reports on the synthesis and the physicochemical properties of novel unsymmetrically substituted zinc phthalocyanines (complexes 8, 10 and 11) and their symmetrically substituted counterparts (complexes 9, 12 and 13). The new complexes and their counterparts were successfully structurally characterized by IR, NMR, mass spectral and elemental analyses. Low fluorescence quantum yields (0.032) and lifetimes (0.91 ns) were obtained for the symmetrical ZnOTPc (complex 9) compared to the higher fluorescence quantum yields (0.15, 0.13, 0.10, 0.09 and 0.29) and lifetimes (4.4, 1.69, 1.69, 2.16 and 3.23 ns) obtained for ZnMPCPc (8), ZnTDTPc (12), ZnMCapPc (10), ZnMCafPc (11) and ZnTCPPc (13), respectively. All the complexes showed the ability to produce singlet oxygen with the highest triplet quantum yields obtained for 8 and 10 (0.80 and 0.65 respectively). High triplet lifetimes (109–286 μs) were obtained for all complexes. Complex 8 showed the longest triplet and fluorescence lifetimes as well the largest triplet state and singlet oxygen quantum yields.
- Full Text:
- Date Issued: 2012
- Authors: Rapulenyane, Nomasonto , Antunes, Edith M , Masilela, Nkosiphile , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/242389 , vital:51037 , xlink:href="https://doi.org/10.1016/j.jphotochem.2012.09.007"
- Description: This work reports on the synthesis and the physicochemical properties of novel unsymmetrically substituted zinc phthalocyanines (complexes 8, 10 and 11) and their symmetrically substituted counterparts (complexes 9, 12 and 13). The new complexes and their counterparts were successfully structurally characterized by IR, NMR, mass spectral and elemental analyses. Low fluorescence quantum yields (0.032) and lifetimes (0.91 ns) were obtained for the symmetrical ZnOTPc (complex 9) compared to the higher fluorescence quantum yields (0.15, 0.13, 0.10, 0.09 and 0.29) and lifetimes (4.4, 1.69, 1.69, 2.16 and 3.23 ns) obtained for ZnMPCPc (8), ZnTDTPc (12), ZnMCapPc (10), ZnMCafPc (11) and ZnTCPPc (13), respectively. All the complexes showed the ability to produce singlet oxygen with the highest triplet quantum yields obtained for 8 and 10 (0.80 and 0.65 respectively). High triplet lifetimes (109–286 μs) were obtained for all complexes. Complex 8 showed the longest triplet and fluorescence lifetimes as well the largest triplet state and singlet oxygen quantum yields.
- Full Text:
- Date Issued: 2012
Synthesis and physicochemical behavior of new low symmetry Ge, Ti and Sn phthalocyanines
- Masilela, Nkosiphile, Nyokong, Tebello
- Authors: Masilela, Nkosiphile , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/242421 , vital:51040 , xlink:href="https://doi.org/10.1016/j.synthmet.2012.07.028"
- Description: The synthesis and photophysicochemical properties of new low symmetrically Ge, Sn and Ti phthalocyanines substituted with one carboxy containing group are reported. Broading and splitting in the absorption spectra were observed for some of the complexes in particular for both the titanium Pcs due to loss of symmetry. Higher fluorescence quantum yields and lifetimes were obtained for the Pcs substituted with three benzyloxy (5–7) compared to their corresponding counterparts substituted with six 2-diethylaminoethylthiol groups (9–11). The germanium Pc complexes gave the highest triplet and singlet oxygen quantum yields compared to all the other complexes studied in DMF. All the complexes showed reasonable ability to generate singlet oxygen with quantum yields ranging from 0.54 to 0.69.
- Full Text:
- Date Issued: 2012
- Authors: Masilela, Nkosiphile , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/242421 , vital:51040 , xlink:href="https://doi.org/10.1016/j.synthmet.2012.07.028"
- Description: The synthesis and photophysicochemical properties of new low symmetrically Ge, Sn and Ti phthalocyanines substituted with one carboxy containing group are reported. Broading and splitting in the absorption spectra were observed for some of the complexes in particular for both the titanium Pcs due to loss of symmetry. Higher fluorescence quantum yields and lifetimes were obtained for the Pcs substituted with three benzyloxy (5–7) compared to their corresponding counterparts substituted with six 2-diethylaminoethylthiol groups (9–11). The germanium Pc complexes gave the highest triplet and singlet oxygen quantum yields compared to all the other complexes studied in DMF. All the complexes showed reasonable ability to generate singlet oxygen with quantum yields ranging from 0.54 to 0.69.
- Full Text:
- Date Issued: 2012
The photophysical and energy transfer behaviour of low symmetry phthalocyanine complexes conjugated to coreshell quantum dots
- Masilela, Nkosiphile, Nyokong, Tebello
- Authors: Masilela, Nkosiphile , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/243051 , vital:51111 , xlink:href="https://doi.org/10.1016/j.jphotochem.2012.07.016"
- Description: This work reports on the synthesis of new coreshell quantum dots (QDs)-low symmetry phthalocyanines conjugates. The energy transfer from QDs (donor) to phthalocyanines (acceptor) was investigated when the two are mixed together or chemically linked to each other. Ti monocarboxy phthalocyanine QDs-linked and Sn monocarboxy phthalocyanine QDs-linked gave the smallest centre-to-centre separation distance (r) corresponding to their higher Förster resonance energy transfer efficiencies which are estimated at 0.76 and 0.85 respectively. Higher energy transfer behaviour was achieved for all the covalently linked conjugates compared to their corresponding mixed counterparts. An improvement in triplet quantum yields and lifetimes was achieved for all the complexes in the presence of quantum dots, with the linked counterparts displaying excellent triplet state behaviour.
- Full Text:
- Date Issued: 2012
- Authors: Masilela, Nkosiphile , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/243051 , vital:51111 , xlink:href="https://doi.org/10.1016/j.jphotochem.2012.07.016"
- Description: This work reports on the synthesis of new coreshell quantum dots (QDs)-low symmetry phthalocyanines conjugates. The energy transfer from QDs (donor) to phthalocyanines (acceptor) was investigated when the two are mixed together or chemically linked to each other. Ti monocarboxy phthalocyanine QDs-linked and Sn monocarboxy phthalocyanine QDs-linked gave the smallest centre-to-centre separation distance (r) corresponding to their higher Förster resonance energy transfer efficiencies which are estimated at 0.76 and 0.85 respectively. Higher energy transfer behaviour was achieved for all the covalently linked conjugates compared to their corresponding mixed counterparts. An improvement in triplet quantum yields and lifetimes was achieved for all the complexes in the presence of quantum dots, with the linked counterparts displaying excellent triplet state behaviour.
- Full Text:
- Date Issued: 2012
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