Duygu Uzun - Academia.edu (original) (raw)

Papers by Duygu Uzun

Spectroscopy Letters, 1998

Abstract N,N′-bis(2-hydroxy-4-benzoic acid)-3,4,9,10-perylenebis(dicarboximide) is synthesized fr... more Abstract N,N′-bis(2-hydroxy-4-benzoic acid)-3,4,9,10-perylenebis(dicarboximide) is synthesized from perylene 3,4,9,10-tetracarboxylic dianhydride and 4-amino-3-hydroxy benzoic acid in 90% yield. Together with the photostability the dye is also very stable thermally. The fluorescence quantum yield is measured as one, Qf=1.The diimide dissolves in water at PH = 8 completely. The diimide is an ideal reference probe for fluorescence quantum yield measurements in 500–650 nm region and an attractive photosensitizer for the photoreactions occur in water.

Photochemical & Photobiological Sciences, 2003

Three novel naphthalene diimides (1-3) and a cyclophane (4) containing two naphthalene diimide mo... more Three novel naphthalene diimides (1-3) and a cyclophane (4) containing two naphthalene diimide moieties were synthesized and characterized. In contrast to the absorption spectra, the emission spectra were strongly dependent on the solvent polarity. The excimer-like emission and low fluorescence rate constant suggest the formation of ground state complexes in DMF. All the compounds have low fluorescence quantum yields (0.001-0.012). They undergo reversible electron reduction and oxidation while deltaEp values depend strongly on solvent polarity. The LUMO energy values of 1 (3.76 eV), 2 (3.69 eV), and 3 (3.66 eV) vary with the substituent pattern. The structurally relatively rigid cyclophane 4 exhibits excellent thermal stability, a high glass transition temperature (tg, 102 degrees C) and a low LUMO energy value (3.59 eV). Compound 2 is insoluble in DMF at room temperature, but begins to dissolve at 37 degrees C and could therefore potentially serve as a sensor in temperature-sensing devices.

Journal of Photochemistry and Photobiology A: Chemistry, 2003

N,N-Bis(4-cyanophenyl)-1,4,5,8-naphthalenediimide (CN-NDI) and N,N-bis(4-cyanophenyl)-3,4,9,10-pe... more N,N-Bis(4-cyanophenyl)-1,4,5,8-naphthalenediimide (CN-NDI) and N,N-bis(4-cyanophenyl)-3,4,9,10-perylenebis(dicarboximide) (CN-PDI) have been synthesized under special conditions in high yield. The compounds are characterized by UV-Vis, IR, NMR, MS, DSC, TGA and CV measurements. The fluorescence lifetimes, quantum yields and singlet-state energies are presented. CN groups at the phenyl moieties improve the thermal stability of the compounds. The LUMO energy values, −3.91 eV (CN-NDI in solution) and −3.96 eV (CN-NDI and CN-PDI at solid state), are determined by cyclic voltammetry. Whereas CN-NDI shows two reversible (−0.89 and −1.34 V) reduction steps (vs. Fc) in solution, CN-NDI and CN-PDI exhibit only one reversible wave at −0.48 V vs. Ag/AgCl at solid state, assigned to the one-electron reduction. Formation of aggregates shifts the UV absorption spectrum of CN-PDI to shorter wavelengths and its lifetime is measured as 4.6 ns at 580 nm. CN-PDI may be a promising dye for organic solar cells.

Photochemical & Photobiological Sciences, 2008

Journal of Photochemistry and Photobiology A: Chemistry

Abstract Novel, one bay-substituted perylene bisanhydride (6) and two bay-substituted perylene bi... more Abstract Novel, one bay-substituted perylene bisanhydride (6) and two bay-substituted perylene bisimides (7, 10) have been successfully synthesized with a large and swallow tail type, 2-decyl-1-tetradecanoyl substituents at the bay area (1 and 7 positions). The non-bay-substituted perylene bisimides with the same N-substituents were prepared as model compounds (3, 9) for comparison. Absorption and fluorescence, electrochemical, spectroelectrochemical, morphological properties of the compounds were investigated, and then, density functional theory (DFT) simulations were conducted. The compounds 6, 7 and 10 have shown J-aggregated featureless, very broad absorbance through the UV–vis-NIR region with a strong fluorescence quenching attributed to efficient intramolecular electron transfer from electron donor 2-decyl-1-tetradecanoyl substituent to PDI acceptor and scaffolds allow π–π intermolecular interactions, induced molecular aggregation. The absolute positions of LUMO and HOMO values for 3, 9, 6, 7 and 10 in solutions were −3.91/−6.09 eV, −3.93/−6.08 eV, −4.02/−5.90 eV, −4.02/−5.91 eV and −4.02/−5.97 eV, respectively. The onset reduction potential of compounds 6, 7 and 10 are lower than those of compounds 3 and 9. Similarly, the onset oxidation potential values of the compounds 6, 7 and 10 are smaller than those of the non-bay-substituted perylene dyes 3 and 9. The synthesized compounds (3 with 7; 9 with 10) can be exploited as an off-on fluorescence probes for photonic applications.

Photochemical & Photobiological Sciences, 2003

Three novel naphthalene diimides (1-3) and a cyclophane (4) containing two naphthalene diimide mo... more Three novel naphthalene diimides (1-3) and a cyclophane (4) containing two naphthalene diimide moieties were synthesized and characterized. In contrast to the absorption spectra, the emission spectra were strongly dependent on the solvent polarity. The excimer-like emission and low fluorescence rate constant suggest the formation of ground state complexes in DMF. All the compounds have low fluorescence quantum yields (0.001-0.012). They undergo reversible electron reduction and oxidation while deltaEp values depend strongly on solvent polarity. The LUMO energy values of 1 (3.76 eV), 2 (3.69 eV), and 3 (3.66 eV) vary with the substituent pattern. The structurally relatively rigid cyclophane 4 exhibits excellent thermal stability, a high glass transition temperature (tg, 102 degrees C) and a low LUMO energy value (3.59 eV). Compound 2 is insoluble in DMF at room temperature, but begins to dissolve at 37 degrees C and could therefore potentially serve as a sensor in temperature-sensing...

Spectroscopy Letters, 2001

Spectroscopy Letters, 1998

Abstract N,N′-bis(2-hydroxy-4-benzoic acid)-3,4,9,10-perylenebis(dicarboximide) is synthesized fr... more Abstract N,N′-bis(2-hydroxy-4-benzoic acid)-3,4,9,10-perylenebis(dicarboximide) is synthesized from perylene 3,4,9,10-tetracarboxylic dianhydride and 4-amino-3-hydroxy benzoic acid in 90% yield. Together with the photostability the dye is also very stable thermally. The fluorescence quantum yield is measured as one, Qf=1.The diimide dissolves in water at PH = 8 completely. The diimide is an ideal reference probe for fluorescence quantum yield measurements in 500–650 nm region and an attractive photosensitizer for the photoreactions occur in water.

Photochemical & Photobiological Sciences, 2003

Three novel naphthalene diimides (1-3) and a cyclophane (4) containing two naphthalene diimide mo... more Three novel naphthalene diimides (1-3) and a cyclophane (4) containing two naphthalene diimide moieties were synthesized and characterized. In contrast to the absorption spectra, the emission spectra were strongly dependent on the solvent polarity. The excimer-like emission and low fluorescence rate constant suggest the formation of ground state complexes in DMF. All the compounds have low fluorescence quantum yields (0.001-0.012). They undergo reversible electron reduction and oxidation while deltaEp values depend strongly on solvent polarity. The LUMO energy values of 1 (3.76 eV), 2 (3.69 eV), and 3 (3.66 eV) vary with the substituent pattern. The structurally relatively rigid cyclophane 4 exhibits excellent thermal stability, a high glass transition temperature (tg, 102 degrees C) and a low LUMO energy value (3.59 eV). Compound 2 is insoluble in DMF at room temperature, but begins to dissolve at 37 degrees C and could therefore potentially serve as a sensor in temperature-sensing devices.

Journal of Photochemistry and Photobiology A: Chemistry, 2003

N,N-Bis(4-cyanophenyl)-1,4,5,8-naphthalenediimide (CN-NDI) and N,N-bis(4-cyanophenyl)-3,4,9,10-pe... more N,N-Bis(4-cyanophenyl)-1,4,5,8-naphthalenediimide (CN-NDI) and N,N-bis(4-cyanophenyl)-3,4,9,10-perylenebis(dicarboximide) (CN-PDI) have been synthesized under special conditions in high yield. The compounds are characterized by UV-Vis, IR, NMR, MS, DSC, TGA and CV measurements. The fluorescence lifetimes, quantum yields and singlet-state energies are presented. CN groups at the phenyl moieties improve the thermal stability of the compounds. The LUMO energy values, −3.91 eV (CN-NDI in solution) and −3.96 eV (CN-NDI and CN-PDI at solid state), are determined by cyclic voltammetry. Whereas CN-NDI shows two reversible (−0.89 and −1.34 V) reduction steps (vs. Fc) in solution, CN-NDI and CN-PDI exhibit only one reversible wave at −0.48 V vs. Ag/AgCl at solid state, assigned to the one-electron reduction. Formation of aggregates shifts the UV absorption spectrum of CN-PDI to shorter wavelengths and its lifetime is measured as 4.6 ns at 580 nm. CN-PDI may be a promising dye for organic solar cells.

Photochemical & Photobiological Sciences, 2008

Journal of Photochemistry and Photobiology A: Chemistry

Abstract Novel, one bay-substituted perylene bisanhydride (6) and two bay-substituted perylene bi... more Abstract Novel, one bay-substituted perylene bisanhydride (6) and two bay-substituted perylene bisimides (7, 10) have been successfully synthesized with a large and swallow tail type, 2-decyl-1-tetradecanoyl substituents at the bay area (1 and 7 positions). The non-bay-substituted perylene bisimides with the same N-substituents were prepared as model compounds (3, 9) for comparison. Absorption and fluorescence, electrochemical, spectroelectrochemical, morphological properties of the compounds were investigated, and then, density functional theory (DFT) simulations were conducted. The compounds 6, 7 and 10 have shown J-aggregated featureless, very broad absorbance through the UV–vis-NIR region with a strong fluorescence quenching attributed to efficient intramolecular electron transfer from electron donor 2-decyl-1-tetradecanoyl substituent to PDI acceptor and scaffolds allow π–π intermolecular interactions, induced molecular aggregation. The absolute positions of LUMO and HOMO values for 3, 9, 6, 7 and 10 in solutions were −3.91/−6.09 eV, −3.93/−6.08 eV, −4.02/−5.90 eV, −4.02/−5.91 eV and −4.02/−5.97 eV, respectively. The onset reduction potential of compounds 6, 7 and 10 are lower than those of compounds 3 and 9. Similarly, the onset oxidation potential values of the compounds 6, 7 and 10 are smaller than those of the non-bay-substituted perylene dyes 3 and 9. The synthesized compounds (3 with 7; 9 with 10) can be exploited as an off-on fluorescence probes for photonic applications.

Photochemical & Photobiological Sciences, 2003

Three novel naphthalene diimides (1-3) and a cyclophane (4) containing two naphthalene diimide mo... more Three novel naphthalene diimides (1-3) and a cyclophane (4) containing two naphthalene diimide moieties were synthesized and characterized. In contrast to the absorption spectra, the emission spectra were strongly dependent on the solvent polarity. The excimer-like emission and low fluorescence rate constant suggest the formation of ground state complexes in DMF. All the compounds have low fluorescence quantum yields (0.001-0.012). They undergo reversible electron reduction and oxidation while deltaEp values depend strongly on solvent polarity. The LUMO energy values of 1 (3.76 eV), 2 (3.69 eV), and 3 (3.66 eV) vary with the substituent pattern. The structurally relatively rigid cyclophane 4 exhibits excellent thermal stability, a high glass transition temperature (tg, 102 degrees C) and a low LUMO energy value (3.59 eV). Compound 2 is insoluble in DMF at room temperature, but begins to dissolve at 37 degrees C and could therefore potentially serve as a sensor in temperature-sensing...

Spectroscopy Letters, 2001