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    A BODIPY decorated multiple mode reusable paper-based colorimetric and fluorometric pH sensor
    (Elsevier, 2022) Ozturk, Dilek; Omeroglu, Ipek; Gol, Cem; Durmus, Mahmut
    In this study, two difluoroboradiazaindacene (BODIPY) compounds bearing diethylaminostyryl groups were synthesized in order to establish colorimetric and fluorometric paper-based pH sensors. The structures of these novel BODIPY compounds were identified by NMR (H-1, C-13, B-11, and F-19), elemental analysis, MALDI-TOF, FT-IR, UV-vis and fluorescence spectroscopies as well as single-crystal X-Ray data. The DFT study was also per-formed to optimize of these two novel BODIPY structures. Electrochemical measurements were applied to estimate their redox potentials. Photophysical properties such as fluorescence quantum yield and lifetimes were investigated to determine the effect of acid addition in both DMSO and 1,4-dioxane solutions of the studied BODIPY derivatives. Also, pKa values of the synthesized compounds (1a and 1b) were determined from absorbance and fluorescence measurements by acid titration studies. The paper-based pH sensor behavior of these BODIPY derivatives was investigated and their performances were determined on the lemon juice samples as a real sample analysis. A simple, cost-effective, rapid, portable, colorimetric, and fluorometric paper-based BODIPY sensing platform was developed in this study for the detection of the variety of pH changes in lemon juice.
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    One-pot hydrothermal conversion of different residues to value-added chemicals using new acidic carbonaceous catalyst
    (Elsevier Sci Ltd, 2019) Özsel Kaya, Burçak; Ozturk, Dilek; Niş, Berna
    The direct hydrothermal conversion of waste biomass to 5-hydroxymethyl furfural (5-HMF) and levulinic acid was studied here in the presence of new biomass-derived sulfonated carbonaceous solid acid catalysts. Different cheap and waste lignocellulosic/cellulosic biomass materials (wheat straw, corn straw, cotton linter and industrial textile fluff) were used as feedstock to prepare bio-based chemicals in an eco-friendly and economical process. The yields of products were improved by optimization of reaction temperature, reaction time and catalyst type for various types of biomass. Under the optimum reaction conditions BT300S sulfonated solid acid carbonaceous catalyst has exhibited higher activity compared to commercial Amberlyst 15 thus 403.7 ppm 5-HMF (16.2 mg 5-HMF/g biomass) and 1624.8 ppm LA (65.6 mg LA/g biomass) have been generated from corn straw biomass in aqueous media at 200 degrees C in 1 h.
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    Photophysicochemical and electrochemical properties of pyrene-BODIPY platforms
    (Royal Soc Chemistry, 2024) Omeroglu, Ipek; Koksoy, Baybars; Ozturk, Dilek; Salah, Lubna; Maksheed, Saad; Durmus, Mahmut
    The photochemical, photophysical, and electrochemical properties of BODIPY compounds (1-7) substituted with iodine or pyrene at the 2-, 6-, or 8-positions (meso) were thoroughly investigated in this study. Through the incorporation of iodine and/or pyrene moieties into the BODIPY derivatives, we evaluated their impact on the photophysical properties using both steady-state and time-resolved fluorescence analyses. Notably, the heavy atom effect induced by iodine was observed, leading to an increase in singlet oxygen quantum yield in proportion to fluorescence intensity. Furthermore, the introduction of pyrene at the meso position in BODIPY (compound 5) significantly enhanced the pi-conjugated system and facilitated the generation of singlet oxygen. Intriguingly, compound 7, which featured pyrene substitutions at positions 2, 6, and 8, exhibited a reduced singlet oxygen yield when compared to the iodine-substituted compound 6. Moreover, we conducted an evaluation of the electrochemical properties of the BODIPY compounds (1-7) in dichloromethane. Additionally, we characterized the structures of the synthesized compounds (5 diamond , 6, and 7) using various spectroscopic techniques, including FT-IR, HRMS, and NMR (1H, 13C, 19F, and 11B), which were performed for the first time within the scope of this study. The comprehensive findings obtained from this extensive research contribute valuable knowledge that has the potential to guide the development of highly efficacious photosensitizers for applications in photodynamic therapy. The photochemical, photophysical, and electrochemical properties of novel BODIPY compounds substituted with iodine or pyrene groups at the 2-, 6-, or 8-positions (meso) were thoroughly investigated.