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    Chemoselective hydrogenation of aromatic nitro compounds in the presence of homogeneous Pd based catalysts
    (Pergamon-Elsevier Science Ltd, 2021) Zengin, Nursefa; Goksu, Haydar; Sen, Fatih
    The chemoselective reduction of aromatic nitro compounds to amine derivatives was easily performed with remarkable yields under ultrasonic conditions in a H2O/MeOH mixture (v/v = 1/4). In this process, commercially available BINAP.PdCl2 and NaBH4 were used as homogenous catalysts and the hydrogen source, respectively. The developed method has a high economic value and can be adapted to the industry. A variety of nitroarene derivatives were reacted by undergoing the BINAP.PdCl2 catalyzed reduction reaction. All nitroarenes were selectively hydrogenated to aromatic primary amines with quantitative yields in 15 min. The obtained primary amines were determined by 1H and 13C nuclear magnetic resonance spectroscopy.
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    Highly Active and Reusable Pd/AlO(OH) Nanoparticles for the Suzuki Cross-Coupling Reaction
    (Bentham Science Publ Ltd, 2018) Göksu, Haydar; Zengin, Nursefa; Karaosman, Arife; Şen, Fatih
    Background: Biphenyl derivatives are an important component of many natural products and used in the treatment of conditions such as anxiety disorders, infections, and insomnia. In addition, the synthesis of these molecules is very important due to their kinase inhibitory effect as well as their antibacterial and antifungal effects. In this study, highly efficient and reusable Pd/AlO(OH) Nanoparticles (NPs) were used as an alternative heterogeneous catalysts system for the coupling reactions. Methods: Pd/AlO(OH) Nanoparticles (NPs) was characterized by SEM, XRD and TEM. Later, Pd/AlO(OH) nanoparticles were performed for coupling reactions. At the end of the reaction, the main products were checked with GC and the GC yield calculated. The desired biaryl products were successfully obtained within 2 h with good yields in the presence of Pd/AlO(OH) nanoparticles. Results: The morphologies of the Pd/AlO(OH) NPs were characterized by scanning electron microscopy (SEM) and x-ray diffraction (XRD). The determination of the appropriate reaction conditions for the desired biaryl products is of crucial importance for successful synthesis. For this purpose, optimization of the conditions for conversion of iodobenzene to biphenyl. was carried out in detail. The reusability of the PdAlO(OH) NPs was also examined for Suzuki Cross-Coupling Reaction. On the other hand, the high temperature and type of catalyst are the factors that make it easier to reach the activation energy. For this reason, the comparison of the designed catalytic system with recently published works are given for Suzuki cross-coupling of bromobenzene with aryl boronic acid. Last but not least, the reaction mechanism of the Suzuki cross-coupling reaction has been entirely identified in the presence of PdAlO(OH) NPs. Conclusion: A novel method was developed for the synthesis of biphenyl derivatives in a short time with high yields by the help of Pd/AlO(OH) NPs at room temperature. As starting materials, neither phenylboronic acid, nor aryl halide derivatives are water soluble, so it was desirable to conduct the reactions in water/isopropyl alcohol as an eco-friendly solvent. Thus, the developed method is both ecofriendly and economical and can be considered as a viable alternative to prior methods appearing in the literature.
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    Metal Organic Frameworks Based Materials for Renewable Energy Applications
    (Materials Research Forum Llc, 2019) Göksu, Haydar; Zengin, Nursefa; Şen, Fatih
    Crystalline metal-organic frames (MOFs) fall into the category of high potential porous materials that can be used in gas storage, adsorption / separation, adsorption as adsorbent, catalysis, magnetism, sensor design and drug delivery. MOFs are typically formed by self-assembly, where secondary building units (SBUs) are connected with organic ligands to form complex networks. Organic ligands or metallic SBUs may be modified to be critical for their functionality and utility for specific applications in order to control the porosity of MOFs. MOFs are used in renewable energy and environmental applications, application of hydrogen energy, hydrogen storage, storage and conversion of CO2, biogas production, thermal energy storage, rechargeable batteries and supercapacitors and in dye sensitized solar cells.
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    A Novel Hydrogenation of Nitroarene Compounds with Multi Wall Carbon Nanotube Supported Palladium/Copper Nanoparticles (PdCu@MWCNT NPs) in Aqueous Medium
    (Nature Publishing Group, 2020) Goksu, Haydar; Zengin, Nursefa; Burhan, Hakan; Cellat, Kemal; Sen, Fatih
    A novel nanocatalyst, multi-wall carbon nanotube supported palladium/copper (PdCu@MWCNT) nanoparticles, was synthesized for the reduction of nitroarene compounds. Characterization of the nanocatalyst was achieved by XRD, XPS, TEM, and Raman spectroscopy analysis. In this study, the hydrogenation of nitroarenes to primary amine compounds was achieved in aqueous medium at room temperature. The aniline derivatives were synthesized with high yields at mild conditions via novel PdCu@MWCNT nanocatalyst. The conversion of nitroarenes to amine derivatives was accomplished at 99% efficiency. In addition to its high activity, the PdCu@MWCNT catalyst was determined to be stable and reusable after the 3rd consecutive use for the reaction and provided 99% conversion of various compounds in the reduction reaction.
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    Synthesis of benzylidenemalononitrile by Knoevenagel condensation through monodisperse carbon nanotube-based NiCu nanohybrids
    (Nature Publishing Group, 2020) Zengin, Nursefa; Burhan, Hakan; Savk, Aysun; Goksu, Haydar; Sen, Fatih
    Monodisperse nickel/copper nanohybrids (NiCu@MWCNT) based on multi-walled carbon nanotubes (MWCNT) were prepared for the Knoevenagel condensation of aryl and aliphatic aldehydes. The synthesis of these nanohybrids was carried out by the ultrasonic hydroxide assisted reduction method. NiCu@MWCNT nanohybrids were characterized by analytical techniques such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM), and Raman spectroscopy. According to characterization results, NiCu@MWCNT showed that these nanohybrids form highly uniform, crystalline, monodisperse, colloidally stable NiCu@MWCNT nanohybrids were successfully synthesized. Thereafter, a model reaction was carried out to obtain benzylidenemalononitrile derivatives using NiCu@MWCNT as a catalyst, and showed high catalytic performance under mild conditions over 10-180 min.