Comparing Singlet Oxygen Generation of Schiff Base Substituted Novel Silicon Phthalocyanines by Sonophotochemical and Photochemical Applications

Abstract

Although the sonophotodynamic method has an effective therapeutic outcome for anticancer treatment compared with the photodynamic method, there are not enough related studies in the literature and this study aims to contribute to the development of sonophotodynamic studies. For this purpose, the Schiff base substituted silicon phthalocyanines were designed and synthesized as effective sensitizer candidates and the photophysicochemical and sonophotochemical features of the phthalocyanines were examined to increase singlet oxygen efficiency. The calculated ΦΔ values indicate that the contribution of substituent groups improved the production of singlet oxygen compared with silicon (IV) phthalocyanine dichloride (SiPcCI2) and also the sonophotochemical applications increased the singlet oxygen yields. The ΦΔ values (ΦΔ = 0.76 for axially bis‐{4‐[(E)‐(pyridin‐3‐ylimino)methyl]phenol} substituted silicon (IV) phthalocyanine (2a), 0.68 for axially bis‐4‐[(E)‐{[(pyridin‐3‐yl)methyl]imino}methyl]phenol substituted silicon (IV) phthalocyanine (2b) in photochemical study) reached to ΦΔ = 0.98 for 2a, 0.94 for 2b in sonophotochemical study. This article will enrich the literature on increasing singlet oxygen yield.

Design consideration of phthalocyanines as sensitizers for enhanced sono-photodynamic combinatorial therapy of cancer

“…Axial ligands alter the geometry of the Pcs and may improve their solubility 81 , 82 . A selection of various axially substituted SiPcs have been reported for SDT/SPDT, including the Pc 27 –Pc 40 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 . Some of the Pcs with axial ligands that have been studied for SDT and or SPDT are shown in Fig.…”

“…The SPDT yields are higher compared to PDT treatments. 85 7.05 × 10 15 photons/(s·cm 2 ), 20 s Pc 31 674 SPDT 35 kHz, 20 s – – Increase in 1 O 2 yields for SPDT compared to PDT treatments 86 7.05 × 10 15 photons/(s·cm 2 ), 20 s Pc 32 674 SPDT 35 kHz, 20 s – – 87 7.05 × 10 15 photons/(s·cm 2 ), 20 s Pc 33 696 SPDT 35 kHz, 20 s – – 88 Pc 34 695 7.05 × 10 15 photons/(s·cm 2 ), 20 s Pc 35 673 SPDT 0.5 W, 60 s Prostate (PC3) cells In vitro ROS yields of axially-substituted Pcs is enhanced compared to SiCl 2 . Cytotoxicity increased for SPDT compared to PDT treatments.…”

Effect of Direct Alkyne Substitution on the Photophysical Properties of Two Novel Octasubstituted Zinc Phthalocyanines

“…Their photophysical properties can be fine‐tuned through the addition of substituents to the periphery or nonperiphery of the macrocycle, or by changing the nature of the metal in the center [13,14] . Based on all these properties, Pcs can be shown potential for photodynamic cancer therapy (PDT) [15–17] . However, since most of the Pcs have poor solubility in various organic solvents, including chloroform (CHCl 3 ), dichloromethane (DCM), toluene, ethyl acetate (EtAc), ethanol (EtOH), methanol (MeOH), THF, and especially in water, their purification and application are limited.…”

“…[ 13 , 14 ] Based on all these properties, Pcs can be shown potential for photodynamic cancer therapy (PDT). [ 15 , 16 , 17 ] However, since most of the Pcs have poor solubility in various organic solvents, including chloroform (CHCl 3 ), dichloromethane (DCM), toluene, ethyl acetate (EtAc), ethanol (EtOH), methanol (MeOH), THF, and especially in water, their purification and application are limited. The solubility of the phthalocyanines can be increased by the binding of long alkyne chains, bulky substituents, or water‐soluble groups to the macrocycle's peripheral or non‐peripheral positions or by the use of isomeric mixtures.…”

“…Phthalocyanine derivatives have a conjugated 18 π electron system and can exhibit different fluorescence properties depending on the type of metal and substituents. [ 3 , 13 , 16 , 17 , 23 , 27 , 28 , 29 ] Substances that exhibit fluorescent properties have the potential to create an image in laser scanning confocal microscopy.…”