A comparative photophysicochemical study of mono substituted phthalocyanines grafted onto silica nanoparticles
- Fashina, Adebayo, Antunes, Edith M, Nyokong, Tebello
- Authors: Fashina, Adebayo , Antunes, Edith M , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193844 , vital:45399 , xlink:href="https://doi.org/10.1142/S1088424614500138"
- Description: In this study, we report on the covalent linking of carboxylic acid functionalized silica nanoparticles with zinc phthalocyanine mono-substituted non-peripherally and peripherally with either a 4-amino phenoxy (1, peripheral and 2, non-peripheral) or an amino group (3 peripheral). The grafting is achieved via the formation of an amide bond between the carboxylic acid of the silica nanoparticles and the amino group of the phthalocyanine complexes. The hybrid nanoparticles retained the amorphous nature of silica nanoparticles after conjugation. A slight decrease in fluorescence and a general improvement in triplet quantum yields compared to free Pcs were observed. Triplet lifetimes for 2-SiNPs and 3-SiNPs also improved when compared to the free phthalocyanine. The changes in singlet oxygen quantum yields upon conjugation were minimal.
- Full Text:
- Date Issued: 2014
- Authors: Fashina, Adebayo , Antunes, Edith M , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193844 , vital:45399 , xlink:href="https://doi.org/10.1142/S1088424614500138"
- Description: In this study, we report on the covalent linking of carboxylic acid functionalized silica nanoparticles with zinc phthalocyanine mono-substituted non-peripherally and peripherally with either a 4-amino phenoxy (1, peripheral and 2, non-peripheral) or an amino group (3 peripheral). The grafting is achieved via the formation of an amide bond between the carboxylic acid of the silica nanoparticles and the amino group of the phthalocyanine complexes. The hybrid nanoparticles retained the amorphous nature of silica nanoparticles after conjugation. A slight decrease in fluorescence and a general improvement in triplet quantum yields compared to free Pcs were observed. Triplet lifetimes for 2-SiNPs and 3-SiNPs also improved when compared to the free phthalocyanine. The changes in singlet oxygen quantum yields upon conjugation were minimal.
- Full Text:
- Date Issued: 2014
Silica nanoparticles grafted with phthalocyanines
- Fashina, Adebayo, Antunes, Edith M, Nyokong, Tebello
- Authors: Fashina, Adebayo , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/232545 , vital:50001 , xlink:href="https://doi.org/10.1039/C3NJ00439B"
- Description: Silica nanoparticles grafted with phthalocyanines (tetra-substituted non-peripherally with 4-carboxyphenoxy and 3-carboxyphenoxy groups) have been synthesized, characterized and their photophysical properties evaluated in solution. The phthalocyanine dyes have a free carboxyl group facilitating the covalent attachment of the dye onto the silica surface via ester bond formation. The photophysical properties of the hybrid nanoparticles show higher fluorescence and triplet quantum yields as well as longer triplet lifetimes as compared to the free phthalocyanines. The triplet quantum yields were found to be higher for the phthalocyanines with ester bonds as compared to the amide bonded linkages. The silica nanoparticles were also studied in artificial lysosomal fluid over a period of 96 h and the dissolution of the nanoparticles was monitored and confirmed using inductively coupled plasma optical emission spectrometry.
- Full Text:
- Date Issued: 2013
- Authors: Fashina, Adebayo , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/232545 , vital:50001 , xlink:href="https://doi.org/10.1039/C3NJ00439B"
- Description: Silica nanoparticles grafted with phthalocyanines (tetra-substituted non-peripherally with 4-carboxyphenoxy and 3-carboxyphenoxy groups) have been synthesized, characterized and their photophysical properties evaluated in solution. The phthalocyanine dyes have a free carboxyl group facilitating the covalent attachment of the dye onto the silica surface via ester bond formation. The photophysical properties of the hybrid nanoparticles show higher fluorescence and triplet quantum yields as well as longer triplet lifetimes as compared to the free phthalocyanines. The triplet quantum yields were found to be higher for the phthalocyanines with ester bonds as compared to the amide bonded linkages. The silica nanoparticles were also studied in artificial lysosomal fluid over a period of 96 h and the dissolution of the nanoparticles was monitored and confirmed using inductively coupled plasma optical emission spectrometry.
- Full Text:
- Date Issued: 2013
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