title: The effect of "on/off" molecular switching on the photophysical and photochemical properties of axially calixarene substituted activatable silicon(iv)phthalocyanine photosensitizers.
abstract: Silicon(iv) phthalocyanines ( and ) bearing two calixarene groups as axial ligands were synthesized. Surprisingly, both phthalocyanines were obtained as two different isomers ( and ) depending on the distance between calixarene benzene groups and the phthalocyanine ring. DFT and TD-DFT computations were performed to model plausible structures of these isomers and to simulate electronic absorption spectra. These isomers converted into each other depending on the polarity of the used solvent, temperature and light irradiation. The photophysical and photochemical properties of each isomer were investigated in dimethylsulfoxide (DMSO) for the determination of photodynamic therapy (PDT) activities of these compounds. The more blue-shifted isomers ( and ) showed higher fluorescence quantum yields and singlet oxygen generation compared to more red-shifted counterparts ( and ). This behavior is extremely important for developing activatable photosensitizers for cancer treatment by PDT. Although these photosensitizers produce lower singlet oxygen in normal cells, they produce higher singlet oxygen (six times higher for ) in cancer cells since these photosensitizers converted to more blue-shifted isomers by using light irradiation.
authors.affiliation: Department of Chemistry, Gebze Technical University, P.O. Box: 141, Gebze, 41400, Kocaeli, Turkey. durmus@gtu.edu.tr and Department of Chemistry Technology, Kocaeli University, Advance Vocational School of Hereke Omer Ismet Uzunyol, Kocaeli, 41800, Turkey.
authors.forename: Ömer
authors.initials: Ö
authors.lastname: Güngör
authors.affiliation: Department of Chemistry Engineering, Çanakkale Onsekiz Mart University, Faculty of Engineering, Terzioglu Campus, 17100, Çanakkale, Turkey.
authors.forename: Gül
authors.initials: G
authors.lastname: Altınbaş Özpınar
authors.affiliation: Department of Chemistry, Gebze Technical University, P.O. Box: 141, Gebze, 41400, Kocaeli, Turkey. durmus@gtu.edu.tr.
authors.forename: Mahmut
authors.initials: M
authors.lastname: Durmuş
authors.affiliation: Department of Chemistry, Gebze Technical University, P.O. Box: 141, Gebze, 41400, Kocaeli, Turkey. durmus@gtu.edu.tr.
authors.forename: Vefa
authors.initials: V
authors.lastname: Ahsen
mesh_terms: D047250:Calixarenes / Q000737:chemistry*; D007211:Indoles / Q000737:chemistry*; D054833:Isoindoles; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000138:chemical synthesis*; D012825:Silicon / Q000737:chemistry*
chemical_list: D007211:Indoles; D054833:Isoindoles; D017319:Photosensitizing Agents; D047250:Calixarenes; C013647:phthalocyanine; D012825:Silicon