Synthesis, photophysicochemical studies of adjacently tetrasubstituted binaphthalo-phthalocyanines
- Seotsanyana-Mokhosi, Itumeleng, Chen, Ji-Yao, Nyokong, Tebello
- Authors: Seotsanyana-Mokhosi, Itumeleng , Chen, Ji-Yao , Nyokong, Tebello
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/289294 , vital:56616 , xlink:href="https://doi.org/10.1142/S108842460500040X"
- Description: Adjacent binaphthalo-phthalocyanines tetra-substituted with phenoxy (4a), 4-carboxyphenoxy (4b) and 4-t-butylphenoxy (4c) groups, as well as the di-substituted 4-carboxyphenoxy (5b) have been synthesized and characterized. The photophysical and photochemical behavior of 4a-c, were compared with those of the corresponding di-substituted derivatives, (5a-c). The secondary substituents on the phenoxy ring have an influence on the aggregation of the molecules and hence on their photophysical properties. All of the complexes exhibit a relatively good conversion of energy from the triplet-excited state to the singlet oxygen. The less aggregated molecule (4c), has the highest singlet oxygen quantum yield. For all the molecules, fluorescence yields are low and they all have relatively shorter triplet lifetimes compared with the unsubstituted zinc phthalocyanine. Increasing the number of ring substituents on these rigid MPc complexes (from complexes 5 to 4) showed a general increase in the triplet state lifetimes and singlet oxygen quantum yields, and a decrease in stability.
- Full Text:
- Date Issued: 2005
- Authors: Seotsanyana-Mokhosi, Itumeleng , Chen, Ji-Yao , Nyokong, Tebello
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/289294 , vital:56616 , xlink:href="https://doi.org/10.1142/S108842460500040X"
- Description: Adjacent binaphthalo-phthalocyanines tetra-substituted with phenoxy (4a), 4-carboxyphenoxy (4b) and 4-t-butylphenoxy (4c) groups, as well as the di-substituted 4-carboxyphenoxy (5b) have been synthesized and characterized. The photophysical and photochemical behavior of 4a-c, were compared with those of the corresponding di-substituted derivatives, (5a-c). The secondary substituents on the phenoxy ring have an influence on the aggregation of the molecules and hence on their photophysical properties. All of the complexes exhibit a relatively good conversion of energy from the triplet-excited state to the singlet oxygen. The less aggregated molecule (4c), has the highest singlet oxygen quantum yield. For all the molecules, fluorescence yields are low and they all have relatively shorter triplet lifetimes compared with the unsubstituted zinc phthalocyanine. Increasing the number of ring substituents on these rigid MPc complexes (from complexes 5 to 4) showed a general increase in the triplet state lifetimes and singlet oxygen quantum yields, and a decrease in stability.
- Full Text:
- Date Issued: 2005
Towards a better grasp of what matters in view of ‘the posts’
- O'Donoghue, Rob B, Lotz-Sisitka, Heila
- Authors: O'Donoghue, Rob B , Lotz-Sisitka, Heila
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182693 , vital:43854 , xlink:href="https://doi.org/10.1080/13504620500169593"
- Description: This response to McKenzie suggests that the issues of representivity, legitimacy and politics, inscribed within an institutional continuism characteristic of modernity within the McKenzie discourse, could well be recast within a reflexive view informed by insights derived with developing social theory. It briefly overviews the struggle for human agency that played out within the deconstructive engagements of the posts and probes how perspectives in social theory are opening the way for a break with features of environmental education as an institutional field. The review points to a reconstituting of the idea of environmental education research from scholastic field of/for environmental awareness and sustainable development, to a reflexive engagement within processes of social reproduction and reorientation in a changing world. A shift such as this would constitute a subtle change in a developing field of research, to situated design decisions of reflexive engagement (research) in social fields constituted within developing cultural contexts of risk.
- Full Text:
- Date Issued: 2005
- Authors: O'Donoghue, Rob B , Lotz-Sisitka, Heila
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182693 , vital:43854 , xlink:href="https://doi.org/10.1080/13504620500169593"
- Description: This response to McKenzie suggests that the issues of representivity, legitimacy and politics, inscribed within an institutional continuism characteristic of modernity within the McKenzie discourse, could well be recast within a reflexive view informed by insights derived with developing social theory. It briefly overviews the struggle for human agency that played out within the deconstructive engagements of the posts and probes how perspectives in social theory are opening the way for a break with features of environmental education as an institutional field. The review points to a reconstituting of the idea of environmental education research from scholastic field of/for environmental awareness and sustainable development, to a reflexive engagement within processes of social reproduction and reorientation in a changing world. A shift such as this would constitute a subtle change in a developing field of research, to situated design decisions of reflexive engagement (research) in social fields constituted within developing cultural contexts of risk.
- Full Text:
- Date Issued: 2005
- «
- ‹
- 1
- ›
- »