Researcher:
Sündü, Buse

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PhD Student

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Buse

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Sündü

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Sündü, Buse

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2021 - 20233

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Researcher Of Publications: search.filters.isAuthorOfPublication.521eb709-5f8f-4068-acad-178d4272144e

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    Catalytic dehydrogenation of natural terpenes via CuPd alloy nanoparticles generated on mesoporous graphitic carbon nitride
    (Wiley, 2023) Mekkaoui, Ayoub Abdelkader; El Houssame, Soufiane; N/A; N/A; N/A; Department of Chemistry; Yalın, Ahsen Sare; Sündü, Buse; Özer, Melek Sermin; Metin, Önder; PhD Student; PhD Student; Researcher; Faculty Member; Department of Chemistry; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; N/A; College of Engineering; N/A; N/A; N/A; 46962
    A facile wet-chemical protocol for the synthesis of bimetallic CuPd alloy nanoparticles (NPs) anchored on mesoporous graphitic carbon nitride (m-gCN), serving as both stabilizer and support material, was presented herein. The presented protocol allowed to synthesize nearly monodisperse CuPd alloy NPs with an average particle size of 3.9 +/- 0.9 nm without use of any additional surfactants and to prepare CuPd/m-gCN nanocatalysts with different Cu/Pd compositions (Cu25Pd75/m-gCN, Cu35Pd65/m-gCN, Cu16Pd74/m-gCN, Cu32Pd68/m-gCN, Cu10Pd90/m-gCN, and Cu50Pd50/m-gCN). After the detailed characterization of CuPd/m-gCN nanocatalysts, they were utilized as catalysts in the dehydrogenation of terpenes. Among all tested nanocatalysts, Cu50Pd50/m-gCN showed the highest activity in terms of the product yields within the same reaction time. Various parameters influencing the catalytic activity of Cu50Pd50/m-gCN were studied using himachalene as a model substrate and the optimum conditions were determined. Under the optimized reaction conditions, the catalytic application of Cu50Pd50/m-gCN nanocatalysts was extended to nine different terpenes and the corresponding products were obtained in high conversion yields (>90%) under mild conditions. A reusability test showed that Cu50Pd50/m-gCN nanocatalysts can be re-used up to four cycles without significant loss in their initial activity.
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    Ag, Co3O4, Ag-Co3O4, and Ag/Co3O4 nanoparticles decorated mesoporous natural phosphate: effect of metal synergy and preparation method on the catalytic reduction reaction
    (Springer, 2022) Orfi, Hamza; Mekkaoui, Ayoub Abdelkader; Laayati, Mouhsine; Labyad, Salim Adam; El Firdoussi, Larbi; El Houssame, Soufiane; N/A; Department of Chemistry; Sündü, Buse; Metin, Önder; PhD Student; Faculty Member; Department of Chemistry; Koç University Surface Science and Technology Center (KUYTAM) / Koç Üniversitesi Yüzey Teknolojileri Araştırmaları Merkezi (KUYTAM); Graduate School of Sciences and Engineering; College of Sciences; N/A; 46962
    Addressed herein is a facile method for the preparation of cobalt-silver (Co-x-Ag-y) nanoparticles decorated mesoporous natural phosphate (m-NP). Various Co-x-Ag-y@NP nanocatalysts were prepared in different forms of Ag and Co3O4 including mono- and bimetallic active sites. The bimetallic nanocatalysts were prepared by two different preparation methods, namely in-situ (Ag-Co3O4) and ex-situ (Ag/Co3O4 core-shell). In the first step, colloidal Co-x-Ag-y nanoparticles were synthesized in solution and their formation was monitored by using UV-Visible spectroscopy. Furthermore, the obtained nanoparticles were characterized by XRD and IR spectroscopy. All nanoparticles were deposited on m-NP using a simple wetness impregnation method followed by a calcination at 500 degrees C. The prepared nanocatalysts were fully characterized by advanced analytical techniques including IR, XRD, XPS, SEM-EDX, FESEM, and TEM. The catalytic reduction of 4-nitrophenol was studied as a model reaction to investigate the effect of synergy created between the metals, oxidation state, catalyst structure, and preparation method on their catalytic activity. Accordingly, reaction kinetics and comparative study of various colloidal Co-x-Ag-y and m-NP supported nanocatalysts in the reduction of 4-nitrophenol was carried out. The optimized conditions were used to study the substrate scope of the catalytic reduction over various nitroarenes.
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    The synthesis of new PEPPSI-type N-heterocyclic carbene (NHC)-Pd(II) complexes bearing long alkyl chain as precursors for the synthesis of NHC-stabilized Pd(0) nanoparticles and their catalytic applications
    (Elsevier Science Sa, 2021) Arıcı, Hatice; Fırıncı, Rukiye; Ertuğrul, Engin; Özdemir, Namık; Çetinkaya, Bekir; Günay, Muhammet Emin; N/A; Department of Chemistry; Sündü, Buse; Metin, Önder; PhD Student; Faculty Member; Department of Chemistry; Graduate School of Sciences and Engineering; College of Sciences; N/A; 46962
    Six new N-heterocyclic carbene (NHC) ligands bearing long-chain alkyl groups on N-atom of 5,6-dimethylbenzimidazole skeleton and their Pd(II) complexes (PEPPSI type) with a close formula of trans-[PdX2(NHC)Py] (X = Cl or Br; Py = pyridine) were successfully synthesized. The yielded NHC ligands and their Pd(II) complexes were characterized by elemental analysis, H-1- and C-13 NMR, FT-IR spectroscopy, and mass spectroscopy and the molecular structure of 3f was determined by X-ray crystallography. All synthesized NHC-Pd(II) complexes were air-stable both as powder and in solution under ambient conditions, which allow us to test them as catalysts in Suzuki-Miyaura cross-coupling (SMC) reactions and to use them as precursors for the in situ synthesis of NHC-stabilized Pd(0) nanoparticles (NPs) during the dehydrogenation of ammonia borane (AB) in dry tetrahydrofuran solution at room temperature. In this protocol, AB served both as a reducing agent for the reduction of NHC-Pd(II) complexes to yield NHC-stabilized Pd(0) NPs and a chemical hydrogen storage material for the concomitant hydrogen generation. The in situ synthesized NHC-stabilized Pd(0) NPs were characterized by UV-Vis spectroscopy, TEM, and XRD techniques. The catalytic activity of the in situ generated NHC-stabilized Pd(0) NPs in the dehydrogenation of AB was followed by measuring the volume of hydrogen generated versus time at room temperature. Among the five different NHC-Pd(II) complexes, 3c (dichloro[1-octadesyl3-(2,4,6-trimethylbenzyl)-(5,6-dimethylbenzimidazol-2-ylidene)](pyridine)palladium(II)) yielded the most stable Pd(0) NPs along with the highest catalytic activity in the dehydrogenation of AB (TOF= 37.7 min(-1) at 1 eqv. H-2 release). The B-11-NMR analysis of the THF solution after the catalytic dehydrogenation of AB revealed the formation of cyclopolyborazane, which is one of the important dehydrocoupling products of AB. Additionally, all NHC-Pd(II) complexes provided high yields in the SMC reactions of phenylboronic acid with various aryl bromides bearing electron-withdrawing or electron-donating groups and even for aryl chlorides bearing electron-withdrawing group at room temperature with the low catalyst loadings. This study revealed that the length of the alkyl chain of NHC ligands has a significant effect on the catalytic activity of the NHC-Pd(II) complexes in the SMC reactions, the longer the alkyl chain on the N atom of NHC ligand, the higher activity of NHC-Pd(II) complex in SMC reactions. It also influences the particle size, morphology and catalytic activity of in situ generated Pd(0) NPs in the dehydrogenation of AB.