Yazar "Zafar, Muhammad Naveed" seçeneğine göre listele

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    Benzimidazole-based N-heterocyclic carbene silver complexes as catalysts for the formation of carbonates from carbon dioxide and epoxides
    (Elsevier, 2022) Nawaz, Zahid; Ullah, Habib; Gurbuz, Nevin; Zafar, Muhammad Naveed; Verpoort, Francis; Tahir, Muhammad Nawaz; Ozdemir, Ismail
    A series of left-to-right inequivalent 1,3-disubstituted benzimidazolium halide pro-ligands having the general formula [(BNHCCH2OxMe)-B-R][X] (R = 3-Me-Bn, 3,5-Me-2-Bn, 2,4,6-Me-3-Bn, 2,3,5,6-Me-4-Bn, 2,3,4,5,6-Me-5-Bn, 3,4,5-(OMe)(3)-Bn, or 4-Bu-t-Bn; X = Cl, Br) were synthesized by the alkylation of 1-((3-methyloxetan-3-yl)methyl)benzimidazole. The corresponding Ag complexes, ((BNHCCH2OxMe)-B-R) AgX, were prepared following pro-ligand addition to Ag2O. These compounds were characterized using spectroscopic techniques such as FT-IR, NMR spectroscopy, and single-crystal X-ray diffraction. The solid-state structure of ((3-Me-BnBNHCCH2OxMe))AgCl revealed a linear monomer while [((2,4,6-Me3-BnBNHCCH2OxMe))AgCl](2) was found to exist as a dimer with pseudo trigonal planar geometry about each metal center. The synthesized ((BNHCCH2OxMe)-B-R)AgX complexes were found to be efficient for the addition of carbon dioxide to epoxides to yield value-added cyclic carbonates at ambient pressure. Amongst the investigated complexes, the bimetallic complex [((2,4,6-Me3-BnBNHCCH2OxMe))AgCl](2) was found to be the most active for CO2 insertion, exhibiting favorable activity when compared to known NHC complexes.
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    Design of efficient benzimidazole-derived N- heterocyclic carbene Ag(I) catalysts for aldehyde -amine -alkyne coupling
    (Elsevier, 2024) Nawaz, Zahid; Gurbuz, Nevin; Zafar, Muhammad Naveed; Tahir, Muhammad Nawaz; Ozdemir, Ismail; Trovitch, Ryan J.
    A mild catalytic protocol for aldehyde, amine, and alkyne coupling (A3-coupling) allows for the selective synthesis of propargyl amines using 5,6-dimethylbenzimidazole-derived N-heterocyclic carbene (BNHC) silver(I) catalysts. A series of BNHC Ag(I) halide complexes were synthesized and their structures have been elucidated through the use of multinuclear NMR and FT-IR spectroscopy. Furthermore, the pseudo-linear geometry of two different compounds was substantiated by single-crystal X-ray diffraction. Silver-based A3-coupling was achieved for both acyclic and cyclic secondary amines using a diverse set of alkynes to afford propargyl amines with yields of up to 95 %. The present approach is environmentally benign and water is generated as the sole byproduct.
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    Direct arylation (hetero-coupling) of heteroarenes via unsymmetrical palladium-PEPPSI-NHC type complexes
    (Pergamon-Elsevier Science Ltd, 2021) Nawaz, Zahid; Gurbuz, Nevin; Zafar, Muhammad Naveed; Tahir, Muhammad Nawaz; Ashfaq, Muhammad; Karci, Huseyin; Ozdemir, Ismail
    The growing interest of industry in the field of bi(hetero)arenes compounds, motivated us to synthesize these compounds via homogeneous catalytic route by using Pd PEPPSI-type complexes through direct arylation. In this work, the five new Pd PEPPSI-type complexes bearing NHC spectator ligands were synthesized and characterized by a bunch of spectroscopic techniques. Further confirmations of structural details were provided by a single crystal X-ray diffraction study of one pro-ligand and one complex. All these newly synthesized Pd-carbene complexes were found significantly active as catalysts toward direct arylation of five members heterocyclic compounds such as n-propylthaizole, 2-acetylfurane and 2-acetylthiophene with aryl bromides derivatives. These catalysts give significantly good results within two hours with just 1 mol % catalyst loading.
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    Synthesis of new Pd(NHC)-PEPPSI type complexes as catalysts toward C-C cross-coupling reactions
    (Elsevier, 2021) Nawaz, Zahid; Gurbuz, Nevin; Zafar, Muhammad Naveed; Ozdemir, Namik; Habib, Uzma; Jan, Kalsoom; Ozdemir, Ismail
    The goal of our research is to synthesis homogeneous catalysts, for which we take start from two novel precursors of 1-(3-methyloxetane-3-yl)benzimidazole and 5,6-dimethyl-1-((3-methyloxetane3-yl)benzimidazole. A series of ligands containing 1,3-disubstituted benzimidazolium salts were synthesized from the corresponding precursors to form N-heterocyclic carbene (NHC) ligands. Furthermore, four new Pd(NHC)-PEPPSI type complexes were synthesized from these ligands. The structure elucidation of all the synthesized ligands, and complexes was confirmed by various spectroscopic techniques such as NMR, FT-IR. The compounds 1b, 2b, 3a, 3d were confirmed by the X-ray technique. All these complexes were found significantly active as catalysts toward the C-C cross-coupling reaction. (c) 2021 Elsevier B.V. All rights reserved.