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1,3-Dioxane Functionalized Pd-PEPPSI Catalyst for Direct Arylation of Heteroaromatics
(Elsevier, 2021) Ulu, Oznur Dogan
A series of benzimidazolium salts (1a-d) and their Pd-PEPPSI complexes (pyridine-enhanced precatalyst preparation, stabilization, and initiation) (2a-d) were prepared to catalyze the direct arylation of heteroaromatics (2-acetylthiophene and 2-furaldehyde) with various aryl bromides. The structures of all isolated compounds were elucidated based on spectroscopic methods (H-1 and C-13 NMR, FT-IR and LC-MS spectroscopy). Under optimized reaction conditions, C5-arylated products were obtained in moderate to excellent yields in the direct arylation of heteroaromatics. (C) 2021 Elsevier B.V. All rights reserved.
Alkylation of cyclic amines with alcohols catalyzed by Ru(II) complexes bearing N-Heterocyclic carbenes
(Pergamon-Elsevier Science Ltd, 2018) Ulu, Oznur Dogan; Gurbuz, Nevin; Ozdemir, Ismail
This paper includes the synthesis of 2-(1,3-dioxane-2-yl)ethyl substituted benzimidazole substituted N-heterocyclic carbenes precursors and their ruthenium complexes. Synthesized compounds were characterized by elemental analysis and NMR spectroscopy. All complexes have been tested in the alkylation of pyrrolidine and morpholine with alcohols, showing an excellent activity in this reaction. (C) 2017 Published by Elsevier Ltd.
Carboxymethyl chitosan/inulin composite films incorporated with different phenolic compounds as a potential new material for food packaging applications
(Elsevier, 2026) Ulu, Oznur Dogan; Ulu, Ahmet; Birhanli, Emre; Pekdemir, Mustafa Ersin; Ates, Burhan
In this study, three types of biodegradable packaging composite films were developed using a solution casting method for the packaging of food products: Composite films based on carboxymethyl chitosan (CMCS) linked with inulin (INU) and then combined with gallic acid (GA), tannic acid (TA), and naringenin (NAR). The swelling capacity and water vapor permeability of the composite films increased by 3.5-fold compared to the CMCS/INU film, while the moisture content remained almost unchanged. Additionally, the results showed that the incorporation of phenolic compounds significantly improved the UV resistance of composite films, and the UV shielding rate of all composite films reached to 95-99 %. Crucially, the incorporation of phenolic compounds imparted excellent antimicrobial properties as well as remarkable antioxidant activity with over 90 % free radical scavenging rate. While the CMCS/INU film did not show inhibition zone diameter against P. aeruginosa, S. aureus, and C. albicans, the inhibitory zone diameters of the CMCS/INU/TA composite film were found to be 19.75, 22, and 18 mm, respectively. Most importantly, shelf life of green grapes and chicken meat packaged in composite films was effectively extended from 3 days to 12 and 7 days without any decay, respectively. Considering this fact, this study not only provides valuable insights into the development of films with antioxidant and antimicrobial properties but also provides a promising framework for advancing active food packaging technologies.
Design, synthesis, characterization, and biological activities of novel Ag (I)-NHC complexes based on 1,3-dioxane ligand
(Elsevier Science Inc, 2024) Ulu, Oznur Dogan; Kurucay, Ali; Gumushan, Ilkay Yildirim; Ozdemir, Namik; Ates, Burhan; Ozdemir, Ismail
Herein, a series of new Ag(I)-NHC complexes containing 1,3-dioxane group were synthesized by the direct reaction of Ag2O and benzimidazolium salts in light-free conditions. All Ag(I)-NHC complexes were spectrally characterized using 1H, 13C NMR, FT-IR, LC-MS, and elemental analysis. Additionally, the structures of compounds 1a and 1e were elucidated by the single X-ray diffraction techniques. Further, the synthesized Ag(I)-NHC complexes were evaluated for cytotoxicity study on the L-929 cells and the anticancer activity against the HCT 116 and MCF-7 cancer cell lines. Notably, 1a showed significant anticancer activity against HCT 116 with an IC50 of 6.37 f 0.92 mu g/mL compared to cisplatin (IC50 = 36.75 f 1.76 mu g/mL). 1c (IC50 = 3.21 f 1.96 mu g/mL) and 1e (IC50 = 3.72 f 1.12 mu g/mL) exhibited significant anticancer activity against MCF-7 cells and was similar to cisplatin (IC50 = 32.17 f 2.85 mu g/mL). Meanwhile, 1a and 1e displayed the highest selectivity index. Most importantly, the cell viability test showed that 1e induced neglectable cytotoxicity (IC50 = 36.38 f 2.27 mu g/mL) toward L-929 and was similar to cisplatin (IC50 = 36.11 f 2.09 mu g/mL). The anticancer activities of Ag(I)-NHC complexes vary depending on the substituent group of the silver complex and the cell line type. Moreover, the inhibitory mechanism of 1e was not dependent on caspase-associated apoptosis initiated by the lysosomalmitochondrial pathway. Taken together, we conclude that this work provides a simple and rapid protocol for the synthesis of Ag(I)-NHC complexes and the featured Ag(I)-NHC complexes have an anticancer drug potential for biomedical applications.
Direct arylation of heteroaromatic compounds by Pd(OAc)2/tetrakis(N-benzimidazoliummethyl)benzene salt system
(Arkat Usa Inc, 2021) Ulu, Oznur Dogan; Ozdemir, Ismail
Six novel tetrakis(N-benzimidazoliummethyl)benzene salts were synthesized using 1,2,4,5-tetrakis(bromomethyl)benzene with 1-alkylbenzimidazole. The structures of all isolated compounds were elucidated based on spectroscopic methods (H-1 and C-13 NMR, and FT-IR spectroscopy) and were investigated for their catalytic activities in the direct arylation of 2-n-propylthiazole, 2-n-buthyltiophene, 2-n-butylfuran, and 4,5dimethylthiazole. All synthesized salts showed high catalytic activity for direct arylation of heteroaromatic compounds. [GRAPHICS]
Enhanced antioxidant and antimicrobial activities of chitosan/oxidized microcrystalline cellulose blended films with Tribulus terrestris extract for food packaging applications
(Elsevier, 2025) Ulu, Oznur Dogan; Birhanli, Emre; Ulu, Ahmet; Ates, Burhan
Chitosan/oxidized cellulose blended film with Tribulus terrestris (T. terrestris) extract films were successfully produced by casting method. The obtained blend films were characterized by structural, mechanical, optical, permeation, antioxidant, and antimicrobial properties. Finally, these biodegradable blend films were used to prolong the shelf-life of sour cherries. Remarkable physical properties such as water vapor transmission rate, swelling, water solubility, mechanic strength, and UV-vis light transmittance were observed to improve positively. All blend films showed 60-70 % degradation after 30 days of hydrolytic degradation and soil burial. T. terrestris extract increased the tensile strength from 1.1 MPa to a maximum of 2.1 MPa and elongation at break from 16 % to 46 %. Furthermore, blend films with T. terrestris extract showed similar to 4 and similar to 3.7 times higher ABTS(center dot+) and DPPH center dot scavenging potential, respectively. Moreover, the findings also revealed that blend films displayed strong antimicrobial activity against S. aureus, E. coli, and C. tropicalis. Most importantly, the shelf life of sour cherries packaged with blend films was effectively extended up to 10 days. Overall, blended films are a promising potential alternative material to petroleum-based synthetic plastics for use in active food packaging, especially in products with short shelf life such as sour cherry.
Fabrication and characterization of functional chitosan/MXene composite films decorated with lead zirconate titanate nanoparticles
(Elsevier Science Sa, 2025) Ulu, Oznur Dogan; Ulu, Ahmet; Birhanli, Emre; Pekdemir, Mustafa Ersin; Atalay, Selcuk; Gelir, Ali; Ates, Burhan
The current study is intended to enhance unique bioactive and eco-friendly composite films following a simple solvent-casting method by incorporating lead zirconate titanate nanoparticles (PZT NPs) with chitosan (CHS)/ MXene matrix. Different characterization techniques were used in the examination of the obtained composite films and the basic physicochemical properties, electrical properties, antioxidant and antibacterial activities of the composite films were determined. The swelling degree, water uptake, and water solubility of the CHS/ MXene/PZT composite films decreased with the incorporation of PZT NPs, whereas the thermal stability increased. When PZT NPs were added, the tensile strength and elongation at break of composite films reached 1.32 MPa and 29.32 %, respectively, which were obviously higher than that of CHS/MXene film. Meanwhile, composite film had moderate antioxidant properties, which, interestingly, decreased with increasing PZT NPs content. In contrast, the obtained composite films showed good antibacterial activity against E. coli (11.00-16.80 mm) and S. aureus (12.20-18.60 mm), which gradually increased with the amount of PZT NPs. Meanwhile, the order of antibacterial activity was found to be S. aureus > E. coli, showing the selectivity of composite films. These results will shed light on additive selection for functional composite films of several applications.
Integrated experimental-computational elucidation of a new Ag(I)-NHC complex: Synthesis, spectroscopic profiling, DFT/TD-DFT calculations, and QTAIM topological analysis
(Elsevier, 2026) Balazghem, Nour-Elhouda; Ulu, Oznur Dogan; Serin, Sumeyya; Sekkoum, Khaled; Yildirim, Ilkay; Ozdemir, Namik; Ozdemir, Ismail
In this study, the electronic structures, bonding properties, and reactivity profiles of the benzimidazolium salt (1) and its Ag(I) complex (2) were investigated using DFT-based analyses. The structures of the compounds were elucidated by using spectroscopic methods including FT-IR, NMR, and LC-MS. Furthermore, the structure of the Ag(I)-NHC complex was determined by single-crystal X-ray diffraction. The results reveal that, compared to complex 2, 1 possesses a smaller energy gap, enhanced electronic delocalization, and more accessible donoracceptor regions, indicating higher chemical softness and reactivity. In contrast, Ag(I) coordination induces a more stabilized and localized electronic distribution, reduces polarity, and increases structural rigidity. NBO second-order perturbation analysis further demonstrates that while precursor 1 exhibits strong pi ->pi* and lonepair-driven delocalization pathways, complex 2 displays additional ligand-metal donor-acceptor interactions with moderate stabilization energies, confirming the electron-accepting role of the metal center.
Laboratory Applications: Polymers in
(Crc Press-Taylor & Francis Group, 2019) Ulu, Oznur Dogan; Ozdemir, Ismail
N-Heterocyclic carbene (NHC) ligands have been successfully used in organic, inorganic, and organometallic chemistry, and over the past decades, intensive research efforts have been devoted. Herein, we aim to provide an overview of the NHC compounds supported with different polymers, and we intend to present the readers with perspectives and innovative ideas about the existing compounds and strategies in the literature. Herewith, the synthesis procedure of the supported NHC compounds is illustrated in detail. In addition, the catalytic applications of supported NHC compounds are briefly reviewed to discuss the practical use of this technique and to compare with other applications.
NHC based Pd-PEPPSI complexes: synthesis, computational studies and application for Suzuki and direct arylation reactions
(Springer/Plenum Publishers, 2026) Belazghem, Nour-Elhouda; Ulu, Oznur Dogan; Serin, Sumeyya; Yildirim, Ilkay; Sekkoum, Khaled; Ozdemir, Namik; Ozdemir, Ismail
A series of novel air- and moisture-resistant NHC-based pyridine containing palladium PEPPSI-type Pd(II) complexes (2a-e) were synthesized and characterized. The structures of all synthesized complexes were determined by various spectroscopic techniques. In addition, the structure of 2b was elucidated by single X-ray crystallography. The structural and electronic properties of 2a-e were further investigated using DFT calculations, which provided valuable insights into thermodynamic parameters, frontier molecular orbitals, and natural bond orbital interactions. The experimental and theoretical data showed strong agreement, confirming the robustness of the applied methodology. The complexes were successfully employed in the Suzuki cross-coupling of phenylboronic acid with aryl chlorides using green solvents. Also, the complexes were tested for direct arylation reactions and obtained mild to good yields.
NHC-based Pd-PEPPSI complexes: Synthesis, characterization, DFT studies and catalytic activity in Suzuki-Miyaura cross coupling
(Elsevier, 2025) Ulu, Oznur Dogan; Serin, Sumeyya; Ozdemir, Ismail
Three new Pd-PEPPSI complexes (2a-c) with the general formula [PdBr2(NHC)(Py)] were prepared via unsymmetrical benzimidazolium salts containing a 1-3-dioxane group on one of the nitrogen atoms and cyanopropyl, cyclobutyl or 2-methylbenzyl on the other side. All the compounds were isolated in excellent yields (68-85 %) and fully characterized using 1H and 13C NMR, FT-IR, and elemental analysis. Additionally, the DFT (Density functional Theory) calculations carried out on complexes 2a-c offers valuable insights on topics like physicochemical characteristics and reactivity tendencies, as well as further validations to the experimentally obtained data of examined Pd complexes. With regard to structural parameters, experimental and computational findings were revealed to be in alignment. A comparative analysis was conducted of the electronic properties, possible donor-acceptor interactions, and electrostatic surface properties of 2a-c. A close examination of the computational findings reveals that cyanopropyl substitution leads to a relative increase in structural stability. Also, Pd-PEPPSI-type complexes with NHC ligands were applied as catalyst precursors in Suzuki cross-coupling reactions forming a wide range of biaryls with high yields. Therefore, the catalytic activities of the synthesized complexes in the Suzuki reaction were tested. The reactions were carried out at very low catalyst loading (0.25 mol%) in the presence of air using a green water-based solvent (i-PrOH:H2O/1:3). The results demonstrated that the catalysts exhibited high activity in this reaction.
Quantum Chemical Benchmark Study on Valdecoxib, a Potent and Selective Inhibitor of COX-2, and its Hydroxylated Derivative
(2022) Serin, Sümeyya; Ulu, Oznur Dogan
In this work, quantum chemical calculations were performed on valdecoxib (VLB), a highly selective and potent COX-2 inhibitor, and its hydroxylated derivative (1H-VLB), an active metabolite. The geometry optimizations and frequency calculations were carried out by using density functional theory (DFT)/B3LYP functional with the 6- 311++G (d, p) basis set. To define water phase behaviors, calculations were renewed by using universal SMD solvation model for both molecules. Structural and thermodynamic parameters, FT-IR analysis, Mulliken population analysis (MPA), frontier molecular orbital (FMO) analysis, natural bond orbital (NBO) analysis, and electrostatic surface properties were investigated in detail. Quantum chemical reactivity identifiers were calculated separately for both vacuum and water environment in order to evaluate the bioactivity tendency of both mentioned compounds. When the bioactivity of VLB and 1H-VLB molecules were compared based on quantum chemical reactivity identifiers, it was observed that the VLB molecule was more active. Moreover, druglikeness properties of studied molecules were predicted by means of Molinspiration cheminformatics software. Molecular lipophilicity potential (MLP)
Silver and selenium compounds of benzimidazolium salts containing fluorine substituents: Synthesis, characterization, and evaluation of anticancer potentials
(Elsevier Science Sa, 2025) Karakas, Gulsen; Serin, Suemeyya; Mumcu, Akin; Ulu, Oznur Dogan; Ulu, Ahmet; Kurucay, Ali; Ates, Burhan
The applications of fluorine in the field of drug design are expanding at a rapid pace. The development of synthetic methodologies has enabled the creation of new fluorinated motifs. Benzimidazolium salts represent a significant source of N-heterocyclic carbenes (NHCs), a distinctive class of ligands. These salts have a wide range of applications due to their notable qualities. The present study encompasses the synthesis of four novel benzimidazolium salts (1a-d) substituted with 2,6-difluorobenzyl moiety. Subsequently, the prepared salts were utilized in the synthesis of silver complexes (2a-d) and selenium compounds (3a-d). The structures of all compounds were elucidated by 1H, 13C, 19F NMR, HRMS, FT-IR spectroscopies, and elemental analysis techniques. The incorporation of a fluorine atom into the molecular structure of a compound has been known to induce substantial alterations in the biological responses of mentioned compound. Therefore, the cytotoxic effect of these compounds was also evaluated using the MTT assay on HCT116 and L929 cell lines. Acridine orange (AO)/ethidium bromide (EB) staining were used for the detection of apoptosis. Notably, cytotoxicity assays showed that compound 3d displayed approximately 22-fold higher potency against HCT116 than cisplatin. Taken together, this enhanced efficacy signifies the promising role of silver and selenium compounds of benzimidazolium salts containing fluorine substituents in anticancer therapies.
Synthesis and characterization of novel Rh-NHC complexes: addition of phenylboronic acid to aldehydes, DFT/TD-DFT, and QTAIM studies
(Elsevier Science Sa, 2026) Ulu, Oznur Dogan; Serin, Sumeyya; Ozdemir, Ismail
Herein, three new Rh(I)-NHC complexes (2a-c) were synthesized by reacting benzimidazolium salts with the [Rh (OMe)(COD)]2 compound. The structures of the synthesized compounds were elucidated by various spectroscopic methods such as 1H, 13C NMR, FT-IR, and UV-vis spectroscopies, and the elemental analysis technique. A thorough theoretical investigation was conducted to explore the electronic structure, reactivity, donor-acceptor interactions, and thermodynamic properties of newly synthesized Rh-NHC complexes. To this end, Density Functional Theory (DFT) calculations were utilized. The findings reveal that the 3,4,5-trimethoxybenzyl substitution contributes to the formation of a more stable and rigid structure in the Rh complex. Additionally, TDDFT calculations were performed to assess the potential electronic transitions of the complexes 2a-c within a chloroform environment. It is possible to interpret the observed peaks of the three complexes as predominantly associated with intra-ligand pi -> pi* transitions and metal-ligand charge-transfer (MLCT) transitions. The quantum theory of atoms in molecules (QTAIM) was employed to facilitate comprehension of bond characteristics and intermolecular interaction strengths in 2a-c complexes. Furthermore, the complexes were evaluated in the reaction of phenylboronic acid to aldehydes, and satisfactory yields were obtained for the desired products.
Synthesis of palladium complexes containing benzimidazole core and their catalytic activities in direct arylation of heteroaromatic species
(Taylor & Francis Ltd, 2024) Seker, Sema; Ulu, Oznur Dogan; Gurbuz, Nevin; Ozdemir, Namik; Ozdemir, Ismail; Bulbul, Hakan
Herein, we report the synthesis of four new palladium complexes containing a benzimidazole core and examine their catalytic activities in the direct arylation of heteroaromatic species with aryl bromides. The complexes were characterized by H-1 and C-13 NMR spectroscopy, FT-IR spectroscopy, and elemental analysis. In the C-13 NMR spectra, NCHN peaks of Pd(II) complexes were observed between 143.2 and 144.9 ppm. Also, the structure of 2b was determined by single-crystal XRD analysis. The obtained data suggest that the lengths of the Pd-N and Pd-Cl bonds are like those of previous Pd complexes. Direct arylation reactions, using KOAc as base and DMAc as solvent under inert conditions, were carried out with the synthesized complexes in the presence of various aryl bromides, and 2-acetylthiophene, 2-furaldehyde, and 1-methylpyrole-2-carboxaldehyde. Moderate to high yields were obtained under 1% mol catalyst loading conditions. The results showed that electron-donating and electron-withdrawing substituents on the aryl halides may produce coupling products in good yields in the presence of 2a-d. These findings contribute to the synthesis and design of palladium complexes containing benzimidazole cores.
SYNTHESIS, CHARACTERIZATION, AND BIOLOGICAL ACTIVITY OF 1,3-DISUBSTITUTED BENZIMIDAZOLIUM SALT AND ITS Ag-NHC COMPLEX
(Soc Chemists Technologists Madeconia, 2023) Ulu, Oznur Dogan
In this study, a 1,3-dioxane functionalized benzimidazole salt and its Ag-complex were synthe-sized. The prepared compounds were structurally verified by several spectroscopic techniques including 1H NMR, 13C NMR, FT-IR, LC-MS, and C, H, N analysis. Compounds were evaluated for their in vitro antioxidant activity. The salts and their Ag-NHC complexes were further evaluated for their in vitro anti-cancer activities against HCT-116 human colon cancer cells. The results showed that complex 2 exhibited high activity (4.1 times) against the cancer cell lines studied when compared to the reference drug cispla-tin. Stability studies demonstrated that these compounds are stable in aqueous and organic solutions.
Synthesis, characterization, computational studies and biological activities of novel NHC precursor and its silver (I) and selenium compounds
(Elsevier, 2025) Serin, Sumeyya; Karakas, Gulsen; Mumcu, Akin; Ulu, Oznur Dogan; Dik, Gamze; Utku, Tugba; Ates, Burhan
The potential applications of fluorine in drug design are expanding rapidly. The evolution of synthetic methodologies has engendered the conception of novel fluorinated motifs. In the present study, the effective use of N-heterocyclic carbenes (NHCs) in pharmaceutical chemistry was combined with the enhancing role of fluorine groups in bioactivity, and the synthesis of a new NHC precursor (1) containing 2,6-difluorobenzyl group was achieved. Respective Ag-NHC (2) and Se-NHC (3) compounds were prepared from the synthesized NHC precursor. Structural characterization of each compound (1-3) was conducted by H-1, C-13 and F-19 NMR, FT-IR, UV-visible spectroscopy, and elemental analysis methods. The antioxidant activity of these compounds was evaluated by using ABTS and DPPH radical scavenging assays as well as their ability to inhibit the acetylcholine esterase (AChE) enzyme. Besides, density functional theory (DFT) computations were performed in order to comparatively peruse the molecular structures, electronic properties, reactivity tendencies, donor-acceptor interactions, and electrostatic surface properties of compounds 1-3 for both vacuum and CHCl3 phase. The reactivity ranking for the gas phase was clearly determined to be 3 < 2 < 1, based on the calculated energy gap values. The excited state characteristics of 1-3 in CHCl3 were calculated by the TD-DFT method. The antioxidant activity showed that the compounds, particularly compound 3 displayed effective antioxidant activities. According to the enzyme inhibition outcomes, compound 2 (IC50 value 8.43 +/- 0.71 mu M) had the most effective AChE inhibition among the synthesized compounds. Taken together, this investigation revealed the synthesis, characterization of various novel compounds (1-3) with, antioxidant potentials, AChE inhibitory activities, and quantum chemical calculations.
Synthesis, characterization, DFT quantum chemical calculations and catalytic properties of azobenzene-bearing Schiff base palladium(II) complexes for the Suzuki-Miyaura Cross-Coupling reaction in aqueous solvent
(Elsevier, 2025) Duyar, Ayse Inan; Sunbul, Ali Burak; Serin, Sumeyya; Ulu, Oznur Dogan; Ozdemir, Ismail; Ikiz, Mesut; Kose, Muhammet
A series of azobenzene-bearing Schiff base ligands, 4-((E)-(4-ethylphenyl)diazenyl)-2-((E)-(p-tolylimino)methyl) phenol (2), 4-((E)-(4-ethylphenyl)diazenyl)-2-((E)-((4-methoxyphenyl)imino)methyl)phenol (3), 2-((E)-((3,4dimethoxyphenyl)imino)methyl)-4-((E)-(4-ethylphenyl)diazenyl)phenol (4), 2-((E)-((4-chlorophenyl)imino) methyl)-4-((E)-(4-ethylphenyl)diazenyl)phenol (5), 2-((E)-((4-bromophenyl)imino)methyl)-4-((E)-(4-ethylphenyl)diazenyl)phenol (6), 2-((E)-(tert-butylimino)methyl)-4-((E)-(4-ethylphenyl)diazenyl)phenol (7), 2-((E)(cyclohexylimino)methyl)-4-((E)-(4-ethylphenyl)diazenyl)phenol (8) and their homoleptic Pd(II) complexes have been synthesized. Ligand structures were characterized by the combination of 13CNMR , 1HNMR , FTIR, UV-Visible spectroscopy and elemental analyses. According to the UV-visible, FTIR, elemental analyses and HRMS data, the Pd(II) complexes 9-15 are formed by the coordination of N, O atoms of the ligands. Examining the coordination of the free ligands with the central metal ion, the new weak bands observed in the 633-581 and 543-481 cm-1 ranges in the spectra of the Pd(II) metal complexes can be attributed to M-O and M-N stretching peaks, respectively. DFT calculations were performed to determine the optimized structures of Pd(II) complexes utilizing the GAUSSIAN 16 software package with appropriate basis sets. The HOMO and LUMO energies of complexes 9-15 were calculated at the studied theory level in the gas phase. The Delta E values were found to be 3.136-3.239 eV range suggests the high chemical reactivity for those of Pd(II) complexes. In addition, Pd(II) complexes were used as catalysts for Suzuki-Miyaura coupling reactions of phenylboronic acid with aryl bromide in aqueous media. All complexes exhibited notably high catalytic properties in the Suzuki-Miyaura coupling reactions. It was found that the substit & uuml;e groups in the aryl bromide has an impact on the catalytic reaction. In the presence of an electron-withdrawing group such as 4-bromobenzaldehyde, the highest yields were obtained with catalysts 12 and 15, while the lowest yield was observed when catalyst 11 was used with 86 % efficiency.
Synthesis, characterization, in vitro antibacterial, and anticancer studies of Ag(I)-N-heterocyclic carbene (NHC) complexes
(Springer Int Publ Ag, 2023) Ulu, Oznur Dogan; Kurucay, Ali; Ates, Burhan; Ozdemir, Ismail
N-Heterocyclic carbene (NHC) complexes of metals such as Ag(I), Au(I), Pd(II), and Cu(I) are very interesting compounds due to both their catalytic and biological properties. In particular, Ag(I)-NHC complexes show activity as antibacterial, antimicrobial, and anticancer agents. Therefore, in this study, six new Ag(I) complexes were obtained from the reaction of benzimidazolium salts with Ag2O. The structures of the prepared compounds were elucidated by FT-IR, H-1 NMR, C-13 NMR, LC-MS spectroscopic methods, and elemental analysis. The antibacterial activity of all Ag(I)-NHC complexes was evaluated against bacterial strains E. coli as gram-negative and B. subtilis as gram-positive bacteria using ampicillin as a standard antibiotic. Moreover, all Ag(I)-NHC complexes were investigated for anticancer activity against the breast adenocarcinoma cell line (MCF-7). All complexes showed good activity against two bacterial strains, even complexes 2d and 2e had more bactericidal activity against B. subtilis than ampicillin. Moreover, complexes 2a (IC50 6.01 +/- 2.39 mu g/mL) and 2e (IC50 3.40 +/- 0.87 mu g/mL) exhibited a better anticancer effect against to MCF-7 cell line than cisplatin (IC50 82.02 +/- 6.19 mu g/mL). Finally, it is worthy to note that the biochemical outcomes revealed that these complexes may be promising antibacterial and anticancer agents.
Synthesis, crystal structure, and DFT studies of NHC mediated Pd-PEPPSI complex: Application for Suzuki reaction
(Elsevier, 2025) Ulu, Oznur Dogan; Serin, Sumeyya; Ozdemir, Namik; Ozdemir, Ismail
A novel air and moisture resistant Pd-PEPPSI (pyridine-enhanced precatalyst preparation, stabilization, and initiation) complex was synthesized via the reaction of benzimidazolium salt, PdCl2, KBr, K2CO3, and pyridine. The structure was characterized by spectroscopic methods such as 1H and 13C NMR, FT-IR, UV-vis. and single Xray diffraction techniques. In order to evaluate the synthesized Pd complex in a detailed manner in terms of structural, bonding, electronic, and thermodynamic characteristics, DFT-based calculations were carried out at the B3LYP/6-311++G (d, p)/LANL2TZ theory level. Natural bond orbital (NBO) analysis was implemented to provide more insights about the possible donor-acceptor interactions and types of hybridization. Also, TD-DFT calculations were performed to rationalize the nature of the observed electronic transitions. The complex showed high catalytic activity in the Suzuki-Miyaura cross coupling of aryl chlorides with phenylboronic acid. Aryl chlorides bearing either electron- donating or withdrawing substituents afforded a wide range of biaryl derivatives that were isolated in the range of 55-97 % yields (7 examples). The reactions were carried out at very low catalyst loading (0.25 mol%) in the presence of air using a green water-based solvent (ipr:H2O/ 1:3). The palladium complex was found to be efficient for the coupling of aryl chlorides with arylboronic acids under aerobic conditions, affording the corresponding biaryls in high yields.

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