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A hydrazine-bridged dinuclear ruthenium complex: Structural properties and biological activity
(Elsevier, 2023) Erdener, Digdem; Dervisoglu, Gokhan; Ozdemir, Fethi Ahmet; Serbetci, Zafer; Ozdemir, Namik; Dayan, Osman
In this study, a new dimeric Ru(II) complex, [Ru(eta(6)-p-cymene)Cl-2](2) (mu(2)-N-2 H-4) (C1), readily synthesized with a reaction of hydrazine hydrate as ligand and [RuCl2(p-cymene)](2) dimmer in dichloromethane. The C1 complex was characterized structurally using IR, NMR, thermal gravimetry and single-crystal X-ray diffraction and theoretically using DFT techniques. Additionally, electrochemical, and optical properties were investigated in cyclic voltammetry and UV-visible spectroscopy. Furthermore, the C1 complex exhibited great antibacterial activity towards 16 Gram + and Gram - species and cell cytotoxicity towards human SH-SY5Y neuroblastoma cell, DU-145 prostate cancer cell, and A549 lung cancer cell lines. (c) 2022 Elsevier B.V. All rights reserved.
A Schiff base based on triphenylamine and thiophene moieties as a fluorescent sensor for Cr (III) ions: Synthesis, characterization and fluorescent applications
(Elsevier Science Sa, 2020) Kolcu, Feyza; Erdener, Digdem; Kaya, İsmet
[Anstract Not Available]
Colorimetric chemical sensing properties of 3-amino-4-hydroxybenzene- sulfonic acid-based Schiff bases containing electron donor-acceptor groups
(Elsevier, 2023) Yildiz, Elif Akhuseyin; Pepe, Yasemin; Erdener, Digdem; Karatay, Ahmet; Boyacioglu, Bahadir; Unver, Huseyin; Yapar, Gonul
A new series of aminobenzene sulfonic acid-based Schiff bases (1-3) were synthesized from the reaction of 3-amino-4-hydroxybenzenesulfonic acid with 5-methyl, 5-nitro and 5-bromo-salicylaldehyde. The colorimetric and UV-Vis spectroscopic responses of compounds in DMSO to addition of equivalent number of anions (F-, Br-, I-, CN-, SCN-, ClO4-, HSO4-, AcO-, H2PO4-, N3- and OH-) were investigated. Additionally, biological activities of the compounds; antimicrobial and DNA binding properties, were investigated. A DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) free radical method was used to measure antioxidant activity, and 4-hydroxy-3-(2-hydroxy-5-methylbenzylideneamino)benzene sulfonic acid (1) displayed greater antioxidant activity than butylated hydroxytoluene (BHT). Studied compounds demonstrated emission properties over a wide range of visible spectrum, and compound 4-hydroxy-3-(2-hydroxy-5-nitrobenzylideneamino)benzenesulfonic acid (2) has hyp-sochromic shift by incorporating NO2 in comparison with other compounds. Femtosecond transient absorption spectroscopy measurements showed that compounds 4-hydroxy-3-(2-hydroxy-5-nitrobenzylideneamino)benze-nesulfonic acid (2) and 3-(5-bromo-2-hydroxybenzylideneamino)-4-hydroxybenzenesulfonic acid (3), incorpo-rated nitro and bromine groups and possessing electron accepting features have fast triplet transition. This study provides a novel design strategy for biological activity and colorimetric probing features of aminobenzene sul-fonic acid-based Schiff bases.
Colorimetric probe and optical behaviours of new azomethine derivatives of sulfonamide
(Elsevier, 2022) Tekin, Sezen; Karatay, Ahmet; Erdener, Digdem; Yildiz, Elif Akhuseyin; Boyacioglu, Bahadir; Unver, Huseyin; Yıldız, Mustafa
Syntheses, colorimetric anion probe properties, density functional theory (DFT) studies, and optical properties of the Schiffbases; 4-fluoro-N-(2-hydroxy-5-methylbenzylidene) benzenesulfonamide (1), 4fluoro-N-(2-hydroxy-5-nitrobenzylidene)benzenesulfonamide (2) and 4-fluoro-N-[(2-hydroxynaphthalen1-yl)methylene]benzenesulfonamide (3) were reported. The structure of the compounds was elucidated using MS, FTIR, and UV-visible spectroscopic techniques. Their structures were examined by theoretical calculations using density functional theory (DFT). The colorimetric response of the Schiffbase receptors in DMSO was investigated before and after the addition of an equivalent amount of each anion to evaluate the anion recognition properties. The ultrafast transient absorption spectroscopy measurements were performed to investigate the energy transfer dynamics and decay kinetics of the compounds 1-3. The fluorescence and wavelength-dependent pump-probe measurements of the compounds showed that the excited state lifetime of compound 2 is shorter than compounds 1 and 3. The fluorescence properties of compounds 1-3 were compatible with the pump-probe spectroscopy measurements. The compounds with longer ESA lifetimes showed higher fluorescence. (c) 2021 Published by Elsevier B.V.
Colorimetric probing and fluorescent chemosensor features of functionalized sulphonamide-azomethine derivatives
(Elsevier Science Sa, 2022) Yildiz, Elif Akhuseyin; Erdener, Digdem; Tekin, Sezen; Karatay, Ahmet; Boyacioglu, Bahadir; Unver, Huseyin; Yıldız, Mustafa
In this work, we have experimentally synthesized bromosulfonamide-based azomethine compounds through the reaction of 4-bromobenzenesulfonamide with 2-hydroxy-5-iodobenzaldehyde, 2-hydroxy-5-nitrobenzaldehyde, and 2-hydroxy-l-naphthaldehyde. We have also characterized the molecular structure of the investigated compounds with MS, H-1 NMR, FTIR and UV-vis spectra. Theoretically, using DFT and TD-DFT methods, we computed frontier molecular orbitals (FMOs) energies and UV-vis spectra as well. We have also obtained the electron localization function (ELF) maps to identify electrophilic substitution sites in the molecules and density of states (DOS) diagrams to show the composition of the fragment orbitals that contribute to the molecular orbitals. We have investigated steady-state absorption, emission features, and excited state dynamics to better understand the photophysical process of bromosulfonamide-based azomethines. It has been demonstrated that by adding a naphthalene unit, the absorption properties of azomethine into two branches. Besides, azomethine, including heavy iodo atoms, presents a slight decrement in the fluorescence intensity. According to thorough calculations of charge transfer dynamics using femtosecond transient absorption spectra, the bromosulfonamidebased azomethines with iodo atoms and incorporating naphthalene units exhibit an intersystem crossing mechanism following photoexcitation. The colorimetric response of the compounds in DMSO to the addition of the equivalent amount of anions (F- , Br- , I-, CN-, SCN-, ClO4-, HSO4-, AcO-, H2PO4- , N-3(-) and OH-) was investigated. In this regard, while the addition of F- ,CN- ,AcO- , H2PO4- and OH(- )anions into the solution containing the compounds resulted in a significant color change, the addition of Br-, I-, SCN-, ClO4- HSO4- and N-3 anions resulted in no color change.
Exploring Charge Transfer Mechanisms in Schiff Base-Modified N-Doped GQDs: Insights from DFT and Pump-Probe Spectroscopy for Bioimaging Applications
(Wiley-V C H Verlag Gmbh, 2024) Hance, Saadet; Erdener, Digdem; Ozturk, Berfin Ilayda; Yildiz, Elif Akhuseyin; Karatay, Ahmet; Boyacioglu, Bahadir; Unver, Huseyin
In recent developments, graphene quantum dots (GQDs) have emerged as valuable tools for imaging and biosensing. Various modifications on the GQDs with any desired functionality and attachment of organic molecules and/or nanostructures allow tuning their photophysical properties as well as charge transfer dynamics for bioimaging applications. This study focuses on synthesizing and characterizing of polyethyleneimine-functionalized nitrogen-doped GQDs (NC1), Schiff base- functionalized nitrogen-doped GQDs (NC2), and silver nanocomposites of these Schiff base-functionalized nitrogen-doped GQDs (NC3). We explore their absorption and emission properties to understand their interactions in the ground state. Furthermore, ultrafast transient absorption spectroscopy measurements reveal that the presence of NC3 shortens the excited state lifetime of NC1 due to charge transfer, resulting in reduced fluorescence intensity. Both experimental and DFT results suggest the potential of NC3 for bioimaging and sensing applications, making them promising candidates for phototheranostic purposes.
Naked-eye colorimetric anion probing and fluorescent switching features of conjugated Schiff Bases derived from 4-(Trifluoromethyl) benzenesulfonamide
(Elsevier, 2022) Yildiz, Elif Akhuseyin; Tekin, Sezen; Erdener, Digdem; Karatay, Ahmet; Boyacioglu, Bahadir; Unver, Huseyin; Yıldız, Mustafa
In this work, synthesis, spectroscopic, density functional theory (DFT) and photophysical studies of the three conjugated benzenesulfonamide Schiff bases were reported. We also calculated the energies of the frontier molecular orbitals (FMOs) and UV-Vis spectra of Schiff bases theoretically using the DFT and TD-DFT methods. Additionally, photophysical properties were investigated by UV-Vis and fluorescence spectroscopy techniques. The ground state interactions show that the absorption band has been separated into two branches and bathochromatically tuned to the visible region, and fluorescence intensity decreased in the case of the Schiff base incorporated naphthalene unit. Furthermore, the charge transfer dynamics of the compounds were analyzed using femtosecond transient absorption spectroscopy measurements proving the triplet-triplet transitions via intersystem crossing mechanism. Based on the ultrafast pump-probe experimental results, as well as decay kinetics of the compounds, the Schiff base with naphthalene unit, showed a fast transition to the triplet state (1.2 ps) as compared to Schiff bases including methyl (4 ps) and chloro (2.7 ps) units. However, upon the addition of various anions, the molecule structure gains anion sensing and fluorescence switching capabilities under daylight and UV light. The obtained experimental results pointed out that the modification of Schiff base molecules with methyl, chlorine and naphthalene units affected its photophysical properties as well as excited-state dynamics significantly.
Spectroscopic Studies and Crystal Structure of 4-(2-Hydroxy-3-Methoxybenzylideneamino)-N-(5-Methylisoxazol-3-yl) Benzenesulfonamide
(Springer/Plenum Publishers, 2010) Yıldız, Mustafa; Unver, Hueseyin; Erdener, Digdem; Iskeleli, Nazan Ocak
Schiff base 4-[(2-hydroxy-3-methoxybenzylideneamino)-N-(5-methylisoxazol-3-yl)benzene-sulfonamidehas been synthesized from the reaction of 4-amino-N-(5-methylisoxazol-3-yl)benzenesulfonamide(sulfamethoxazole) with 2-hydroxy-3-methoxybenzaldehyde. It has been characterized by elemental analysis, MS, IR, H-1 NMR, C-13 NMR, HET-COR and UV-Visible techniques. The structure of it also has been examined crystallographically. For the compound exist as dominant form of enol-imines in both the solid state and the solutions. It crystallizes in the monoclinic space group P2(1)/c with a = 8.2694(7), b = 8.3453( 5), c = 26.260( 2) angstrom, beta = 97.142(7)degrees, V = 1798.1(2) angstrom(3) , D-x = 1.431 g cm(-3), R-1 = 0.0529 and wR(2) = 0.1370 [ I > 2 sigma(I)], respectively.
Superb ruthenium(ii) complex melody: Uncovering its hidden catalytic and biological properties
(Pergamon-Elsevier Science Ltd, 2024) Duman, Sibel; Dervisoglu, Gokhan; Ozdemir, Fethi Ahmet; Serbetci, Zafer; Erdener, Digdem; Dayan, Osman
Aliphatic/aromatic nitrogen-substituted ligands have a very important role in ruthenium chemistry. Polydentate ligands with N-substituted pyridine rings are notable for their ability to easily modify the electronic and steric properties of ruthenium. In this study, the catalytic and biological activities of the [RuCl2(NNN)(CH3CN)] (NNN: 2,6-di(1H-pyrazol-3-yl)pyridine)) complex were examined for two different applications. Firstly, the superb Ru(II) complex was used to catalyze the methanolysis of NaBH4, and its initial rate was calculated as 69360 mLH(2)min(-1)g(cat)(-1). Secondly, the biological activities of the superb Ru(II) complex were examined. Accordingly, it was determined that this homogeneous complex showed anti-microbial activity on all bacteria used in the study, among the Gram-positive bacteria used in the study, the best result belongs to the Bacillus cereus EMC 19 bacterium with 8 mm, while among the Gram-negative bacteria, the best zone diameter belongs to the Pseudomonas aeruginosa DSM 50071 bacterium with 5 mm. However, it was observed that zone diameters varied between 8 mm and 3 mm. Compared to the control group, it was determined that 0.25 mg/mL concentration had 94.87%, 0.5 mg/mL concentration 96.10%, 1 mg/mL concentration 96.50%, and 2 mg/mL concentration 97.09% cytotoxic activity on the SH-SY5Y cell line. it was determined that all doses of the superb Ru(II) complex used in the study showed anti-cancer activity, but the anticancer activity shown at low doses was statistically more significant at the p < 0.05 level.
Synthesis and Characterization of a Carbazole-Based Schiff Base Capable of Detection of Al3+ in Organic/Aqueous Media
(Springer/Plenum Publishers, 2022) Erdener, Digdem; Kaya, İsmet
A new fluorescence probe (L) selectively detecting Al3+ ions was synthesized via the condensation reaction, and characterized using UV-Vis, FT-IR, H-1-NMR and C-13-NMR spectroscopic techniques. The limit of detection for Al3+ ions of this synthesized probe was found to be 9.29 x 10(-7) M, while the Ka constant value was determined to be 1.64 x 10(4) M-1. The stoichiometric binding ratio of L-Al3+ was found to be 2:1 using the Job's plot method, and this ratio was also confirmed by H-1-NMR titration and mass spectrometry. The recyclability of the chemosensor was found by the fluorescence method through the addition of EDTA to the L-Al3+ solution. The obtained data showed that the carbazole-based Schiff base acted as an ideal chemosensor for Al3+.
Synthesis and characterization of a pyrene-based Schiff base and its oligomer: Investigation of fluorescent Cr3+ probe
(Elsevier, 2022) Yeldir, Elif Karacan; Erdener, Digdem; Kaya, İsmet
In this study, a unique Schiff base (SP) was synthesized from 1-aminopyrine (1-AP) and salicylaldehyde (SA) compounds. The obtained oligomer of this Schiff base was carried out by the oxidative polymerization method. The structural characterizations of 2-((pyren-1-yl-imino)methyl)phenol (SP) and oligo-2-((pyren-1-yl-imino)methyl)phenol (OSP) by FT-IR, H-1 NMR and C-13 NMR measurements, electrochemical properties by cyclic voltammetry (CV); optical properties by UV/Vis studies and photoluminescence (PL) spectrophotometry; thermal stability were performed by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The molecular weight of the obtained oligomer was determined using gel permeation chromatography (GPC). Accordingly, Mn and Mw values of OSP were found to be 2800 and 3150 Da, respectively. The imine bond provided the structures with high thermal stability, and the maximum mass loss temperatures (T-max) of SP and OSP were found to be 350(0) and 343 degrees C, respectively. PL study showed that SP could be used as a Cr3+ sensor among a series of metals. The results revealed that the limit of detection (LOD) value of SP was 1.03 x 10(-)(9) M and was not affected by other ions in the environment.
Synthesis and spectroscopic properties of geminal-bis(tert-butylamino)cyclotriphosphazenes obtained by the reaction of Spiro and ansa phenoxycyclotriphosphazenes with the tert-butylamine and the crystal structure of 4,4?-bis(tert-butylamino)-2,6?,6?,10-tetrachloro-4?,4?,6?,6?-tetrahydrospyro[12H-dibenzo[d,g]- (1,3,2]dioxaphosphocin-6,2??5-[1,3,5,2,4,6]-triazaphosphorine]
(Serbian Chemical Soc, 2011) Erdener, Digdem; Yıldız, Mustafa; Unver, Huseyin; Iskeleli, Nazan Ocak; Durlu, Tahsin Nuri
The condensation reactions of partly substituted spiro and ansa phcnoxycyclotriphosphazenes 1 and 2 with tert-butylamine produce disubstituted geminal-bis(tert-butylamino)phenoxycyclotriphosphazene derivatives (3 and 4). The structures of these compounds were characterized by elemental analysis, and IR, H-1-, C-13-, P-31-NMR and mass spectroscopic techniques. Compound 3 was also examined by X-ray crystallography and found to be crystallized in the monoclinic space group P2(1)/n with the unit cell parameters: a = = 10.842(4), b = 9.375(5), c = 29.104(11) angstrom, beta = 99.25(3), V= 2920(2) angstrom(3), D-x = 1.404 g cm(-3).
Synthesis and Spectroscopic Properties of Spiro, Ansa and Bino Phosphazenes
(Asian Journal Of Chemistry, 2012) Erdener, Digdem; Yıldız, Mustafa
The spiro (1, 2), ansa (3) and bino (4) phosphaza-lariat ethers have been synthesized. The structures of the compounds (1, 2, 3 and 4) are characterized by elemental analysis, mass spectrometry, IR, H-1, C-13 and P-31 NMR spectroscopy.
Synthesis, DFT computations and antimicrobial activity of a Schiff base derived from 2-hydroxynaphthaldehyde: Remarkable solvent effect
(Elsevier, 2020) Tercan, Melek; Ozdemir, Namik; Ozdemir, Fethi Ahmet; Serbetci, Zafer; Erdener, Digdem; Cetinkaya, Bekir; Dayan, Osman
A new Schiff base bearing sulfonamide group was synthesized and characterized by spectroscopic techniques. Its spectroscopic properties were investigated through density functional theory (DFT/B3LYP) method with the 6-311++G(d,p) basis set theoretically and the zwitterion reversible arrow enol tautomerization was studied using IEF-PCM approximation. The thermodynamic (entropy, enthalpy and Gibbs free energy changes) and energetic quantities of the zwitterion reversible arrow enol tautomerization indicate that the migration of single proton between zwitterion reversible arrow enol tautomer's is unfavored for both directions in all phases. During the change from the water phase to the gas phase, the tautomeric energy barrier increases for the proton transfer reaction from the zwitterion form to the enol form, while the barrier decreases from the enol form to the zwitterion form. On the other hand, experimental studies (UV-vis. and NMR spectroscopies) release that there are two tautomeric species which are the zwitterion form in polar and the enol form in apolar solvents for the soluted compound. Furthermore, the antibacterial effect of the compound was investigated in two different solvents (DMSO and THF) to demonstrate the effect of dominant tautomeric species. The results indicate that the solution in which the enol form is dominant than the zwitterionic form has more antimicrobial efficiency for all bacterial species. (C) 2020 Elsevier B.V. All rights reserved.
Synthesis, spectroscopic studies and crystal structure of (E)-2-(2,4-dihydroxybenzylidene)thiosemicarbazone and (E)-2-[(1H-indol-3-yl)methylene]thiosemicarbazone
(Elsevier, 2009) Yıldız, Mustafa; Unver, Huseyin; Erdener, Digdem; Kiraz, Askin; Iskeleli, Nazan Ocak
Thiosemicarbazone Schiff bases (1 and 2) derived from 2,4-dihydroxybenzaldehyde, indoline-3-carbaldehyde and thiosemicarbazone have been synthesized and their structures were elucidated by elemental analysis. FT-IR, H-1 NMR, C-13 NMR and UV-visible spectroscopic techniques. The structures of compounds 1 and 2 have also been examined cyrstallographically. The title compounds 1 and 2 crystallize in the monoclinic space group C-2/c and triclinic space group P (1) over bar, with unit cell parameters: a = 21.421 (1) and 7.233(1), b = 4.131(1) and 11.166(1), c = 24.942(2) and 13.648(1) angstrom, V = 1856.1(2) and 1019.5(1) angstrom(3), D-x = 1.512 and 1.422 g cm(-3) and Z = 8 and 4, respectively. (C) 2008 Elsevier B.V. All rights reserved.
UV-Vis spectroscopic and colorimetric anion detection and fluorescence properties of new 3-amino-4-hydroxybenzenesulfonic acid-based Schiff bases depending on the strength and position of the electron donor substitution
(Iop Publishing Ltd, 2023) Yildiz, Elif Akhuseyin; Pepe, Yasemin; Erdener, Digdem; Karatay, Ahmet; Boyacioglu, Bahadir; Unver, Hueseyin; Yapar, Gonul
In this study, 3-amino-4-hydroxybenzenesulfonic acid-based imine compounds; 3-(2,5-dihydroxybenzylideneamino)-4-hydroxybenzenesulfonic acid (1), 3-(2,4-dihydroxybenzylideneamino)-4-hydroxybenzenesulfonic acid (2) and 4-hydroxy-3-(2-hydroxy-3-methoxybenzylideneamino)-4-hydroxybenzenesulfonic acid (3) was synthesized. The compounds were analyzed using various spectroscopy methods, and the experimental UV-vis data matched the theoretical predictions. The compound 1 displayed lower stability, higher reactivity, and easier photoexcitation due to a smaller HOMO-LUMO energy gap. The investigated compounds 1-3 showed promise as chemosensors for anions, providing visible detection in daylight conditions. The compound 3 exhibited selective fluorescence at specific wavelengths. The compounds 1-3 interacted with DNA through electrostatic interactions. Also, compounds 1-3 showed higher antioxidant activity than BHT. However, fluorescence measurements indicated that the emission signals were strongly influenced by the position and strength of the electron-donating group. Adding a hydroxy or methoxy moiety near the -OH group on the phenyl ring decreased the fluorescence signal due to intersystem crossing and intramolecular charge transfer mechanisms, respectively. These findings were supported by femtosecond transient absorption spectroscopy measurements. The results emphasize the significance of substituents in imines derived from 3-amino-4-hydroxybenzenesulfonic acid in determining their biological activities, as well as their optical and sensor properties.

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