title: A comparative photophysicochemical study of phthalocyanines encapsulated in core-shell silica nanoparticles.
abstract: This work presents the synthesis and characterization of a new zinc phthalocyanine complex tetrasubstituted with 3-carboxyphenoxy in the peripheral position. The photophysical properties of the new complex are compared with those of phthalocyanines tetra substituted with 3-carboxyphenoxy or 4-carboxyphenoxy at non-peripheral positions. Three phthalocyanine complexes were encapsulated within silica matrix to form a core shell and the hybrid nanoparticles particles obtained were spherical and mono dispersed. When encapsulated within the silica shell nanoparticles, phthalocyanines showed improved triplet quantum yields and singlet oxygen quantum yields than surface grafted derivatives. The improvements observed could be attributed to the protection provided for the phthalocyanine complexes by the silica matrix.
authors.affiliation: Department of Chemistry, Rhodes University, Grahamstown 6140, South Africa.
authors.forename: Adedayo
authors.initials: A
authors.lastname: Fashina
authors.affiliation: Department of Chemistry, Rhodes University, Grahamstown 6140, South Africa.
authors.forename: Edith
authors.initials: E
authors.lastname: Amuhaya
authors.affiliation: Department of Chemistry, Rhodes University, Grahamstown 6140, South Africa. Electronic address: t.nyokong@ru.ac.za.
authors.forename: Tebello
authors.initials: T
authors.lastname: Nyokong
mesh_terms: D004121:Dimethyl Sulfoxide / Q000737:chemistry; D007211:Indoles / Q000138:chemical synthesis / Q000737:chemistry*; D054833:Isoindoles; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D055668:Photochemical Processes; D011789:Quantum Theory; D012822:Silicon Dioxide / Q000737:chemistry*; D026082:Singlet Oxygen / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D017967:Zinc Compounds
chemical_list: D007211:Indoles; D054833:Isoindoles; D009942:Organometallic Compounds; D017967:Zinc Compounds; C052159:Zn(II)-phthalocyanine; D026082:Singlet Oxygen; D012822:Silicon Dioxide; D004121:Dimethyl Sulfoxide
keywords: Carboxyphenoxy phthalocyanine; Core–shell; Silica matrix; Triplet quantum yields