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Öğe 7-Oxy-3-(3,4,5-trimethoxyphenyl)coumarin substituted phthalonitrile derivatives as fluorescent sensors for detection of Fe3+ ions: Experimental and theoretical study(Elsevier Science Sa, 2014) Kaya, Esra Nur; Yuksel, Fatma; Ozpinar, Gul Altinbas; Bulut, Mustafa; Durmus, MahmutThe novel 7-hydroxy-3-(3,4,5-trimethoxyphenyl) coumarin (1) has been synthesized via Perkin reaction and its phthalonitrile derivatives (2, 3, 4 and 5) have also been prepared from the reaction of this coumarin (1) with 3-nitrophthalonitrile, 4-nitrophthalonitrile or 4,5-dichlorophthalonitrile compounds for the first time in this study. The newly synthesized compounds have been fully characterized by H-1 NMR, MALDI-TOF, FT-IR, UV-vis and fluorescence spectral data as well as elemental analysis. The exact structure of the coumarin substituted phthalonitrile derivatives (2, 3 and 5) have also been determined using X-ray diffraction. The electronic absorption and fluorescence properties of these new compounds have been studied in different solvents. The chemosensor behaviors of these compounds to metal ions have also been examined by fluorescence spectroscopy and these compounds exhibited as fluorescence chemosensor for the determination of Fe3+ ions in solution. Fe3+ complex structures of mono-coumarin ring substituted derivatives (1-4) have been investigated by using density functional theory computations. (C) 2013 Elsevier B.V. All rights reserved.Öğe Asymmetrically tetra-substituted phthalocyanine derivatives: synthesis, photophysical and photochemical properties(Springer, 2022) Dilber, Gulsev; Nas, Asiye; Piskin, Mehmet; Durmus, MahmutThe syntheses of highly soluble asymmetrically substituted metal free and zinc phthalocyanine derivatives bearing three 4-(4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenoxy) and one 4-(2-(benzo[d]thiazol-2-yl)phenoxy) groups or bearing one 4-(4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenoxy) and three 4-(2-(benzo[d]thiazol-2-yl)phenoxy) groups were reported for the first time in this study. The successful synthesis of phthalocyanines was achieved through the common statistical condensation method utilizing two different phthalonitriles named as 4-(4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenoxy)phthalonitrile and 4-(2-(benzo[d]thiazol-2-yl)phenoxy)phthalonitrile. The asymmetrical phthalocyanines were characterized by spectroscopic methods. Moreover, the aggregation behavior, photophysical and photochemical properties of the substituted A(3)B type asymmetrical metal free and Zn (II) phthalocyanines were investigated in DMF. The asymmetrical Zn (II) phthalocyanine complexes produced highly singlet oxygen and appropriate fluorescence behavior in DMF suggesting that they can be suitable candidates as Type II photosensitizers in photodynamic therapy (PDT) applications.Öğe Do the positions of trimethyl groups on phthalocyanine photosensitizers improve their photochemical and photophysical properties?(Elsevier Science Sa, 2017) Cetinkaya, Mehmet; Piskin, Mehmet; Altun, Selcuk; Odabas, Zafer; Durmus, MahmutThe synthesis of novel highly soluble and non-aggregated metal-free and zinc(II) phthalocyanines containing four 2,3,5-trimethylphenoxy groups was achieved by starting phthalonitrile compounds. The phthalocyanines were characterized by elemental analysis, infrared, ultraviolet-visible and matrix assisted laser desorption/ionization time-of-flight mass spectroscopic techniques. Their photochemical and photophysical properties were also investigated in N,N-dimethylformamide. In addition, the influences of position of methyl groups on phenoxy unit and nature of metal in phthalocyanine cavity on photophysical and photochemical properties were investigated by comparing with previous analogues (phthalocyanines with 2,3,6-trimethylphenoxy and 2,4,6-trimethylphenoxy groups). (C) 2016 Elsevier B.V. All rights reserved.Öğe Effects of position (? or ?) and linker heteroatom (O or S) of substituent on the photophysicochemical behavior of poly(oxyethylene) substituted ZnPcs and assessment of J-aggregation or protonation using TD-DFT computations(Royal Soc Chemistry, 2013) Ayhan, Mehmet Menaf; Ozpinar, Gul Altinbas; Durmus, Mahmut; Gurek, Ayse GulA series of zinc phthalocyanines (ZnPcs) tetra-substituted with 1,3-di[2-(2-ethoxyethoxy)ethoxy]-2-propanol (1a) or 1,3-di[2-(2-ethoxyethoxy)ethoxy]-2-propanethiol (1b) at peripheral (beta) (6a-b) and non-peripheral (a) (7a-b) positions have been synthesized and characterized. The spectroscopic, photophysical (fluorescence quantum yields and lifetimes) and photochemical (singlet oxygen generation and photodegradation) properties of these newly synthesized phthalocyanines have been investigated in DMSO. The effects of the position of the substituents on the phthalocyanine skeleton and the nature of the linker heteroatom on their spectroscopic, photophysical and photochemical properties have been determined. The quenching behavior of the zinc phthalocyanines by 1,4-benzoquinone has been studied in DMSO. All of the zinc(II) Pc complexes (6a-b and 7a-b) showed similar electronic absorption spectra in various solvents (chloroform, dichloromethane, DMF, DMSO, THF and toluene). However, complex 7a gave an extra red-shifted band at 742 nm in chloroform and dichloromethane. DFT and TD-DFT computations were performed on the model structures (8a-d, p-8a-d and 9a-d) to find out the cause of the extra red-shifted Q band (J-type aggregation or protonation of the Pc ring). The computational results showed that monoprotonation of a meso nitrogen atom leads to the formation of this extra band. Photophysical and photochemical measurements indicated that these newly synthesized ZnPc derivatives are promising candidates for use as photosensitizers in the application of PDT.Öğe Efficient singlet oxygen generation by triptycene substituted A3B type zinc(II) phthalocyanine photosensitizers(Pergamon-Elsevier Science Ltd, 2016) Al-Sohaimi, Bandar R.; Piskin, Mehmet; Ghanem, Bader S.; Al-Raqa, Shaya Y.; Durmus, MahmutA(3)B type unsymmetrical 8,11,15,18,22,25-hexadecyl-2,3-(9,10-diocty1-6,7-dimethoxy-2,3-dioxytriptycene) (11) and 8,11,15,18,22,25-hexadecyl-2,3-(9,10-diundecy1-6,7-dimethoxy-2,3-dioxytriptycene) (12) zinc(II) phthalocyanines were synthesized for the first time. Their photophysical and photochemical properties were investigated as solutions in toluene and obtained values were compared with unsubstituted zinc(II) phthalocyanine for determination of substitution effect. Both newly synthesized phthalocyanines showed high singlet oxygen generation making them good candidates as photosensitizers for photocatalytic-reactions. (C) 2015 Elsevier Ltd. All rights reserved.Öğe Enhancing photophysical and photochemical properties of zinc(II) phthalocyanine dyes by substitution of triptycene moieties(Elsevier, 2016) Al-Sohaimi, Bander Roshadan; Piskin, Mehmet; Aljuhani, Ateyatallah; Al-Raqa, Shaya Y.; Durmus, MahmutThe symmetrical zinc(II) phthalocyanines conjugated with 9,10-dioctyl-6,7-dimethoxy-2,3-dioxytriptycene or 9,10-diundecyl-6,7-dimethoxy-2,3-dioxytriptycene moieties were synthesized in this study. These novel phthalocyanines were characterized by standard characterization techniques such as 1HNMR, FT-IR, UV-vis, Mass and Elemental Analysis. All these phthalocyanines showed highly solubility and formed non-aggregated monomeric species in most of the organic solvents. Their photochemical properties such as singlet oxygen, and photodegradation quantum yields, and photophysical properties including fluorescence quantum yields and lifetimes were investigated in toluene. The fluorescence quenching behavior of the studied zinc(II) phthalocyanines by the addition of 1,4-benzoquinone were also described in toluene. (C) 2016 Elsevier B.V. All rights reserved.Öğe First investigation on the photophysical and photochemical properties of azo-bridged phthalocyanine photosensitizers(Elsevier Science Bv, 2016) Sahin, Safinaz; Piskin, Mehmet; Altun, Selcuk; Durmus, Mahmut; Odabas, ZaferNovel azo-bridged indium(III) acetate phthalocyanine was synthesized by cyclotetramerization reaction of (E)-4-((2,5-dimethoxyphenyl)diazenyl)phthalonitrile. This phthalocyanine was fully characterized by FT-IR, H-1-NMR, UV-vis and MALDI-TOF mass spectroscopic techniques and elemental analyses as well. Additionally, the photophysical and photochemical properties of this phthalocyanine was investigated for the first time. The obtained results were compared with azo-bridged zinc(II) and metal-free phthalocyanine counterparts for determination of central metal effect on these properties. These results were also compared with unsubstituted zinc(II) and indium(III)acetate phthalocyanines for determination of substitution effect on the photophysical and photochemical properties. (C) 2016 Elsevier B.V. All rights reserved.Öğe Metal or metal-free phthalocyanines containing morpholine substituents: synthesis, spectroscopic and photophysicochemical properties(Taylor & Francis Ltd, 2022) Demirbas, Umit; Piskin, Mehmet; Durmus, Mahmut; Kantekin, HalitThe phthalonitrile (3) and its peripherally tetra 4-(3-morpholinophenoxy) substituted metal-free (4), lead(II) (5) and zinc(II) (6) phthalocyanine derivatives were synthesized. The structures of 3-6 were confirmed by FT-IR, H-1-NMR, MALDI-TOF mass, UV-vis and fluorescence spectral data. The solubility and aggregation behaviors of 4-6 were determined in dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), tetrahydrofuran (THF), chloroform (CHCl3) and dichloromethane (CH2Cl2). The observed sharp absorptions were evidence of formation of non-aggregated phthalocyanine species at the studied concentration. The effects of the substituent and central metal ions (metal-free, zinc or lead) on spectroscopic and photophysicochemical properties were determined. Their photophysicochemical properties such as fluorescence quantum yields and lifetimes, singlet oxygen generation and photodegradation quantum yields were investigated in DMSO. The fluorescence spectra of metal-free (4) and lead(II) (5) phthalocyanines were not recorded due to negligible fluorescence emissions of these phthalocyanines. The zinc(II) phthalocyanine (6) had 0.17 fluorescence quantum yield (phi(F)) and 1.42 fluorescence lifetime (tau(F)). The phthalocyanines (4-6) had 0.18, 0.41, 0.52 singlet oxygen quantum yields (phi(Delta)) and 0.51, 3.90, 0.46 photodegradation quantum yields (phi(Delta)), respectively. The zinc(II) phthalocyanine (6) in particular could be a potential Type II photosensitizer candidate for photodynamic therapy in cancer treatment.Öğe Metal-free, zinc(II) and lead(II) phthalocyanines functioning with 3-(2H-benzo[d][1,2,3]triazol-2-yl)-4-hydroxyphenethyl methacrylate groups: Synthesis and investigation of photophysical and photochemical properties(Elsevier Science Sa, 2016) Demirbas, Umit; Piskin, Mehmet; Barut, Burak; Bayrak, Riza; Durmus, Mahmut; Kantekin, HalitIn this study, the synthesis and characterization of 3-(2H-benzo[d][1,2,3]triazol-2-yl)-4-hydroxyphenethyl methacrylate substituted novel phthalonitrile compound and its peripherally substituted zinc(II) lead(II) and metal-free phthalocyanine derivatives were performed for the first time. This novel compounds were characterized by obtained data from general spectroscopic methods such as FT-IR, H-1 NMR, C-13 NMR and mass. The photophysical and photochemical properties of these phthalocyanines were investigated in N,N-dimethylformamide solutions for determination of their photosensitizing abilities in photocatalytic applications such as photodynamic therapy. The lead(II) phthalocyanine complex did not produce any fluorescent in N,N-dimethylformamide because of the heavy atom effect of bigger lead atom. The fluorescence quantum yields of studied zinc(II) and metal-free phthalocyanines were found to quite higher than unsubstituted zinc(II) phthalocyanine due to substitution of the phthalocyanine skeleton. The influence of substituent and variety of the central metal ions on spectroscopic, photophysical and photochemical properties were also determined and compared. (C) 2016 Elsevier B.V. All rights reserved.Öğe New metallophthalocyanines including benzylphenoxy groups and investigation of their organic-field effect transistor (OFET) features(Elsevier Sci Ltd, 2022) Ozdemir, Mucahit; Altinisik, Sinem; Koksoy, Baybars; Canimkurbey, Betul; Koyuncu, Sermet; Durmus, Mahmut; Bulut, MustafaIn this study, metal and metal-free novel phthalocyanines containing peripheral and non-peripheral tetra 2-ben-zylphenoxy groups were synthesized. The compounds were characterized by UV-Vis, FT-IR, H-1 NMR, and MALDI-TOF mass spectrometry as well as elemental analysis. These new phthalocyanines exhibited excellent solubility in most organic solvents, and their redox behavior was investigated in different solvents such as dimethyl sulfoxide (DMSO) and dichloromethane (DCM). The redox behavior of the peripheral and non-peripheral phthalocyanine compounds 1a -c and 2a -c was determined by cyclic voltammetry and in situ spec-troelectrochemistry. According to organic field-effect transistors (OFETs) measurements, the peripheral and non-peripheral phthalocyanine-cobalt complexes which have higher mobility than others were utilized top-gate bottom-contact OFETs fabrication. The output characteristics of the device show that its mobility is approximately 5 x 10(-2) cm(2)/Vs with p-type accumulation.Öğe New peripherally and non-peripherally tetra-substituted metal-free, magnesium(II) and zinc(II) phthalocyanine derivatives fused chalcone units: Design, synthesis, spectroscopic characterization, photochemistry and photophysics(Elsevier Science Sa, 2018) Kantekin, Halit; Yalazan, Halise; Kahriman, Nuran; Ertem, Beytullah; Serdaroglu, Vildan; Piskin, Mehmet; Durmus, MahmutChalcone containing new peripherally and non-peripherally tetra-substituted metal-free and metallophthalo-cyanine derivatives were designed and synthesized (Schemes 1 and 2). The structures of chalcone-phthalocyanines were characterized by a combination of common spectroscopic techniques such as LC-MS/MS (for new phthalonitrile derivative 3a), ground state electronic absorption spectra (for all new phthalocyanines), H-1 NMR spectroscopy (for all new compounds), C-13 NMR spectroscopy (for new phthalonitrile and metal-free phthalocyanine derivatives), Fourier transform infrared (FT-IR with ATR sampling accessory) (for all new compounds) and MALDI-TOF mass spectral data (for all new phthalocyanines and new phthalonitrile derivative 3b) as well as elemental analysis. In addition, the effects of the presence of different kinds of metal ions [magnesium(II) or zinc (II)] in the phthalocyanine core and the effects of the introduction of (3,4-dimethoxyphenyl)-3-oxoprop-1en-1-yl)phenoxy units at both peripheral and non-peripheral positions of the phthalocyanine skeleton on photophysical and photochemical properties of the new substituted magnesium(II) and zinc(II) phthalocyanines have also been examined in DMF. The obtained results were compared with each other and with unsubstituted magnesium(II) and zinc(II) phthalocyanines. All newly synthesized phthalocyanines are soluble in common organic solvents as well as no type of aggregation was observed in these solvents. Moreover; the chalcone fused magnesium(II) and zinc(II) phthalocyanines also showed excellent fluorescence properties. Specifically, the new non-peripheral zinc(II) and magnesium(II) chalcone-phthalocyanines have the remarkable potential to be used as Type II photosensitizers for the treatment of cancer in PDT owing to their good singlet oxygen and appropriate photodegradation quantum yields. Since chalcones and their derivatives show a broad range of biological and pharmaceutical activities, these products are promising candidates for various applications, particularly as photosensitizers for photodynamic therapy in combination with fluorescence imaging.Öğe New peripherally and non-peripherally tetra-substituted water soluble zinc phthalocyanines: Synthesis, photophysics and photochemistry(Elsevier Science Sa, 2015) Cakir, Volkan; Cakir, Dilek; Piskin, Mehmet; Durmus, Mahmut; Biyiklioglu, ZekeriyaThe synthesis and photochemical properties of peripherally and non-peripherally 1,3-bis[3-(dimethy-lamino)phenoxy]prop-2-oxy tetra-substituted zinc phthalocyanines (2a and 3a) and their quaternized derivatives (2b and 3b) were reported in this study. Photochemical properties of quaternized ionic zinc (II) phthalocyanines (2b and 3b) were investigated in both dimethyl sulfoxide (DMSO) and aqueous solutions, while non ionic derivatives were only studied in DMSO. The quaternized compounds exhibit excellent solubility in water, making them potential photosensitizers for use in photodynamic therapy (PDT) of cancer. This study also showed that the water-soluble quaternized Zn(II) phthalocyanines strongly bind to blood plasma proteins such as bovine serum albumin (BSA). On the other hand, the interactions of the novel water soluble phthalocyaines with DNA were also examined. (C) 2015 Elsevier B.V. All rights reserved.Öğe Spectroscopic and electrochemical behavior of the novel tetra-2-methyl-pyrazinoporphyrazines(Elsevier Science Bv, 2017) Piskin, Mehmet; Ozturk, Naciye; Durmus, MahmutThis study presents the synthesis and characterization of novel metal-free (H2Pc) and metallo porphyrazines (magnesium(II) (MgPz), copper(II) (CuPz), iron(II) (FePz), manganese(II) (MnPz) and nickel(II) (NiPz)) substituted with four 2-methylpyrazine groups on the peripheral positions. The spectroscopic properties of newly synthesized porphyrazines were investigated. The electrochemical behaviors of these porphyrazines were also determined in DMSO solution by cyclic voltammetry (CV) and square wave voltammetry (SWV) methods on edge plane pyrolytic graphite electrode (EPPG) electrode. (C) 2017 Published by Elsevier B.V.Öğe Spectroscopic, photophysical and photochemical properties of newly metallo-phthalocyanines containing coumarin derivative(Elsevier, 2020) Capkin, Aylin; Piskin, Mehmet; Durmus, Mahmut; Bulut, MustafaThe new, well-soluble and non-aggregated peripheral or non-peripheral tetra-ethyl 7-oxy-4,8-dimethylcoumarin-3-propanoate substituted magnesium (II), zinc (II) and indium (III) acetate phthalocyanines were synthesized. They were characterized by widely known spectroscopic methods such as UV-vis, IR, MALDI-TOF Mass, H-1 NMR spectroscopies and elemental analysis. Photophysical and photochemical properties were studied in N, N-dimethylformamide to determine the usability of each of these phthalocyanines as photosensitizers. The influences of the position and presence of the coumarin derivative at the phthalocyanine skeleton and metal' nature in the phthalocyanine cavity on photophysical and photochemical properties were investigated by comparing with previous analogues (magnesium, zinc, and indium phthalocyanines containing coumarin derivative with different functional groups). The spectroscopic, photophysical, photochemical data and results obtained for each of these phthalocyanines show that they may have the potential to be used as photosensitizers in photodynamic therapy. (c) 2020 Elsevier B.V. All rights reserved.Öğe Synthesis, characterisation, photophysical and photochemical properties of free-base tetra-(5-chloro-2-(2,4-dichlorophenoxy) phenoxy)phthalocyanine and respective zinc(II) and lead(II) complexes(Elsevier Science Sa, 2017) Demirbas, Umit; Piskin, Mehmet; Akcay, Hakki Turker; Barut, Burak; Durmus, Mahmut; Kantekin, HalitIn this study, novel peripherally tetra-(5-chloro-2-(2,4-dichlorophenoxy)phenol) substituted metal-free (4), zinc(II) (5) and lead(II) (6) phthalocyanine derivatives were synthesised. The novel phthalocyanines (4-6) were characterised by general spectroscopic methods such as IR, H-1 NMR, UV-vis, mass spectrometry and elemental analysis. Once the solubilities of the compounds were investigated, it was noticed that they have excellent solubility and did not tend to aggregation behaviour in common solvents. The photophysical and photochemical properties of novel phthalocyanines (4-6) were investigated in dimethysulfoxide. The effects of substituted 5-chloro-2-(2,4-dichlorophenoxy)phenoxy group and central metal ion [zinc(II)/lead(II)] on photophysical and photochemical properties of the novel phthalocyanines have also been examined, and the results were compared with unsubstituted zinc (II) phthalocyanine. According to photophysical and photochemical investigation results, it was observed that the novel phthalocyanines (4-6) have a potential for PDT application. (C) 2016 Elsevier B.V. All rights reserved.Öğe Synthesis, characterization and investigation of the photophysical and photochemical properties of highly soluble novel metal-free, zinc(II), and indium(III) phthalocyanines substituted with 2,3,6-trimethylphenoxy moieties(Royal Soc Chemistry, 2015) Gurel, Ekrem; Piskin, Mehmet; Altun, Selcuk; Odabas, Zafer; Durmus, MahmutThis work presents the synthesis and characterization of metal-free, zinc((II)), and indium((III)) acetate phthalo-cyanines substituted with 2,3,6-trimethylphenoxy groups at the peripheral and non-peripheral positions. The photophysical (fluorescence quantum yields and lifetimes) and photochemical (singlet oxygen generation and photodegradation under light irradiation) properties of these novel phthalocyanines and un-substituted zinc((II)) and indium((III)) acetate phthalocyanines were investigated in dimethylformamide solution. The effects of the types of substituents and their positions and the variety of central metal ions on the phthalocyanine core on their spectroscopic, photophysical and photochemical properties were also determined. The studied 2,3,6-trimethylphenoxy substituted metal-free, zinc((II)) and indium((III)) acetate phthalocyanines especially indium((III)) acetate derivatives exhibited appropriate photophysical and photochemical properties such as high singlet oxygen generation and these phthalocyanines can be potential Type II photosensitizers for photodynamic therapy in cancer applications.Öğe Synthesis, characterization, photophysical, and photochemical properties of novel zinc(II) and indium(III) phthalocyanines containing 2-phenylphenoxy units(Elsevier Science Bv, 2016) Ali, Haytham Elzien Alamin; Piskin, Mehmet; Altun, Selcuk; Durmus, Mahmut; Odabas, ZaferThe synthesis of highly soluble and non-aggregated peripherally/non-peripherally Zn and In(OAc) phthalocyanines was achieved by 3-/ and 4-(2-phenylphenoxy)phthalonitrile as starting materials. The novel compounds were characterized by elemental analyses, FT-IR, H-1-NMR (for phthalonitriles), UV-vis and MALDI-TOF mass (for Pcs) spectroscopic techniques. Additionally, photophysical, photochemical and spectral properties of the phthalocyanines were reported. Especially, the indium(OAc) phthalocyanines showed good singlet oxygen quantum yields in DMSO and they can be appropriate candidates as Type II photosensitizers in photodynamic therapy (PDT) applications. (C) 2015 Elsevier B.V. All rights reserved.Öğe Synthesis, photophysical and photochemical properties of novel phthalocyanines substituted with triptycene moieties(Pergamon-Elsevier Science Ltd, 2015) Ghanem, Bader S.; Piskin, Mehmet; Durmus, Mahmut; El-Khouly, Mohamed E.; Al-Raqa, Shaya Y.New metal-free and zinc(II) phthalocyanines containing four triptycene moieties were synthesized and characterized by H-1 NMR, mass, IR, electronic spectroscopies and elemental analysis as well. The steady-state absorption spectra of the investigated compounds exhibited the main absorption bands in the visible region, at around 700 nm. The fluorescence spectra and quantum yields were recorded by steady-state emission measurements. The powerful nanosecond laser flash photolysis technique was employed to record the transient absorption spectra of the long-lived triplet states of the investigated compounds. The singlet oxygen generation and photodegradation properties of the target phthalocyanines under light irradiation were also investigated in tetrahydrofuran solution. (C) 2015 Elsevier Ltd. All rights reserved.Öğe The determination of photophysical and photochemical parameters of novel metal-free, zinc(II) and lead(II) phthalocyanines bearing 1,2,4-triazole groups(Elsevier Science Sa, 2016) Demirbas, Umit; Piskin, Mehmet; Bayrak, Riza; Unluer, Dilek; Dugdu, Esra; Durmus, Mahmut; Kantekin, HalitIn this study the synthesis and characterization of novel phthalonitrile compound (3) and its metal-free (4), zinc(II) (5), and lead(II) (6) phthalocyanines bearing four 4-(4-methoxyphenylethyl)-5-propyl-2,4-dihydro-3H-1,2,4-triazol-3-one groups at peripheral positions were synthesized for the first time. These novel compounds were fully characterized by FT-FT-IR, H-1 NMR, UV-vis and MALDI-TOF mass spectroscopic techniques. Their photochemical and photophysical properties were also investigated in N, N-dimethylformamide solutions. In addition, the effect of 4(4-methoxyphenylethyl)-5-propyl-2,4dihydro-3H-1,2,4-triazol-3-one groups as substituents and central metal ions (without metal, zinc(II) or lead(II)) in the phthalocyanine cavity on these properties were also compared. The studied zinc(II) or lead (II) phthalocyanines can be potential Type II photosensitizers for photodynamic therapy in cancer applications because these phthalocyanines showed good singlet oxygen generation and appropriate photodegradation. (C) 2016 Elsevier B.V. All rights reserved.Öğe The effect of on/off molecular switching on the photophysical and photochemical properties of axially calixarene substituted activatable silicon(IV)phthalocyanine photosensitizers(Royal Soc Chemistry, 2016) Gungor, Omer; Ozpinar, Gul Altinbas; Durmus, Mahmut; Ahsen, VefaSilicon(IV) phthalocyanines (4 and 5) bearing two calixarene groups as axial ligands were synthesized. Surprisingly, both phthalocyanines were obtained as two different isomers (4a-b and 5a-b) 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 (4b and 5b) showed higher fluorescence quantum yields and singlet oxygen generation compared to more red-shifted counterparts (4a and 5a). 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 5b) in cancer cells since these photosensitizers converted to more blue-shifted isomers by using light irradiation.