İmranlı Meslek Yüksekokulu Makale Koleksiyonu
https://hdl.handle.net/20.500.12418/699
2024-03-29T07:52:08ZEffects of Heavy Iodine Atoms and π-Expanded Conjugation on Charge Transfer Dynamics in Carboxylic Acid BODIPY Derivatives as Triplet Photosensitizers
https://hdl.handle.net/20.500.12418/14780
Effects of Heavy Iodine Atoms and π-Expanded Conjugation on Charge Transfer Dynamics in Carboxylic Acid BODIPY Derivatives as Triplet Photosensitizers
Akhüseyin-Yıldız, Elif; Yabaş, Ebru; Sözmen, Fazlı; Bozkurt, Yasemin; Karatay, Ahmet; Boyacıoğlu, Bahadır; Ünver, Hüseyin; Elmalı, Ayhan
Borondipyrromethene (BODIPY) chromophores are composed
of a functional-COOH group at meso position with or without a
biphenyl ring, and their compounds with heavy iodine atoms at
����� 2, ����� 6 positions of the BODIPY indacene core were synthesized.
The photophysical properties of the compounds were
studied with steady-state absorption and fluorescence measurements.
It was observed that the absorption band is significantly
red-shifted, and fluorescence signals are quenched in the
presence of iodine atoms. In addition to that, it was indicated
that the biphenyl ring does not affect the spectral shifting in
the absorption as well as fluorescence spectra. In an attempt to
investigate the effect of π-expanded biphenyl moieties and
heavy iodine atoms on charge transfer dynamics, femtosecond
transient absorption spectroscopy measurements were carried
out in the environment of the tetrahydrofuran (THF) solution.
Based on the performed ultrafast pump-probe spectroscopy,
BODIPY compounds with iodine atoms lead to intersystem
crossing (ISC) and ISC rates were determined as 150 ps and
180 ps for iodine BODIPY compounds with and without π-
expanded biphenyl moieties, respectively. According to the
theoretical results, the charge transfer in the investigated
compounds mostly appears to be intrinsic local excitations,
corresponding to high photoluminescence efficiency. These
experimental findings are useful for the design and study of the
fundamental photochemistry of organic triplet photosensitizers.
2023-01-01T00:00:00ZTwo-Photon Absorption Response of Functionalized BODIPY Dyes in Near-IR Region by Tuning Conjugation Length and Meso- Substituents
https://hdl.handle.net/20.500.12418/14779
Two-Photon Absorption Response of Functionalized BODIPY Dyes in Near-IR Region by Tuning Conjugation Length and Meso- Substituents
Akhüseyin-Yıldız, Elif; Ünlü, Bekir Asilcan; Karatay, Ahmet; Bozkurt, Yasemin; Özler, Muhammed Emre; Sözmen, Fazlı; Yabaş, Ebru; Boyacıoğlu, Bahadır; Ünver, Hüseyin; Elmalı, Ayhan
BODIPY dyes substituted by phenol or −COOMe units at the meso-position (C8) with and without a distyryl group including a methoxy moiety at the -C3 and -C5 positions of the BODIPY have been synthesized to analyze the photophysical properties. To clarify the ground-state interaction, absorption and emission features were investigated in the THF environment. Extending the π-conjugation with the methoxy moiety at -C3 and -C5 positions of BODIPY leads to a spectral shifting of the absorption maxima toward red by 120 nm. In addition, attaching the −COOMe unit at the meso-position of the BODIPY structure increases nonradiative molecular relaxation as compared to compounds possessing phenol substituents at the same position. We have investigated the effect of phenol and a −COOMe group and π-extended conjugation length with a methoxy moiety on the properties of two-photon absorption (TPA) and electron transfer dynamics by performing open-aperture (OA) Z-scan and femtosecond transient absorption spectroscopy measurements, respectively. The synthesized BODIPY compounds with the distyryl group including the methoxy unit show TPA character due to the longer conjugation length and therefore intramolecular charge
transfer ability. Based on the OA Z-scan experiments upon photoexcitation with 800 nm pulsed laser light, TPA cross-section values were obtained as 74 and 81 GM for the compounds possessing phenol and −COOMe units at the meso-position of BODIPY treated by distyryl group with methoxy moieties, respectively. Additionally, optical and electronic properties were calculated theoretically by using the DFT method.
2023-01-01T00:00:00ZNovel reduced graphene oxide/zinc phthalocyanine and re duce d graphene oxide/cobalt phthalocyanine hybrids as high sensitivity room temperature volatile organic compound gas sensors
https://hdl.handle.net/20.500.12418/14778
Novel reduced graphene oxide/zinc phthalocyanine and re duce d graphene oxide/cobalt phthalocyanine hybrids as high sensitivity room temperature volatile organic compound gas sensors
Yabaş, Ebru; Biçer, Emre; Altındal, Ahmet
In this work, novel 4-pyridynyl-oxadiazole tetrasubstituted zinc and cobalt phthalocyanine compounds were synthesized and characterized by UV-vis, Fluorescence spectroscopy, and SEM. Then these com- pounds were mixed with reduced graphene oxide. As a result of the interaction of these newly syn- thesized phthalocyanines with reduced graphene oxide (rGO), rGO/ZnPc and rGO/CoPc hybrids were ob- tained. The measurement results confirm that the prepared non-covalent rGO/ZnPc and rGO/CoPc hybrid structures are formed by strong π–πinteraction. A comparative study of the sensor response of rGO and non-covalently functionalized with zinc and cobalt phthalocyanines (rGO/ZnPc, and rGO/CoPc) hybrids to five different volatile organic compound vapors, ammonia, acetone, ethanol, methanol and butanol is car- ried out. The response of the sensors increases with respect to ammonia concentrations ranging from 30 to 210 ppm. The response time for 120 ppm ammonia vapor were approximately 250s, 230s and 190s for rGO, rGO/ZnPc, and rGO/CoPc based sensors, respectively. Also, we have conducted selectivity exper- iments with the aformentioned vapors, thus, studies have indicated that functionalization of rGO with ZnPc results in a 43-fold improvement in sensor response towards ammonia vapors.
2023-01-01T00:00:00ZA comprehensive archaeometric analysis of a novel special organic finding in a glass unguentarium: NMR, FT‑IR, SEM/EDX
https://hdl.handle.net/20.500.12418/14777
A comprehensive archaeometric analysis of a novel special organic finding in a glass unguentarium: NMR, FT‑IR, SEM/EDX
Pehlivan, Erdener; Yabaş, Ebru; Özer, Ali
In this study, systematical analyses were employed to determine that which period the historical artifact belonged, and evaluations were based on the glass-making technology of the period. In addition, since organic substances were carried in these glass bottles, they are likely to be the medicine or ornaments at that time; by using recently developed techniques as NMR, SEM– EDX and interpret them in the correct way, it was possible to predict what the yellow oily looking organic substance might be in. As the mouth of the glass bottle is completely closed with clay, the characterization of this organic material was made on the clay sample taken from the underneath of the environment without damaging the historical artifact. The trace organic matter residues on the clay were isolated and characterized by NMR spectrometry; this sample was characterized with FT-IR. Finally, the surface morphology of the clay–oil mixture was examined morphologically with SEM, and with EDX, elemental analysis was performed. In the results obtained, it was concluded that the organic material in the historical artifact could be olive oil with a high content of palmitic acid. With this study, the content of the artifact could be clarified by making a structural examination of the remains without damaging the historical artifact.
2023-01-01T00:00:00Z