{"title":"Direct arylation of heteroarenes catalyzed by palladium complexes based on N-isopropyl-substituted N-heterocyclic carbenes","authors":"","doi":"10.1016/j.ica.2024.122355","DOIUrl":null,"url":null,"abstract":"<div><p>A series of seven 1-isopropyl-5,6-dimethylbenzimidazolium chlorides with a range of benzyl substituents on their N3 position (<strong>1a</strong>–<strong>g</strong>) were synthesized and used as NHC ligand precursors to prepare the corresponding [PdCl<sub>2</sub>(NHC)(Py)] complexes (<strong>2a</strong>–<strong>g</strong>). The structural analyses of all novel compounds were done by <sup>1</sup>H and <sup>13</sup>C{<sup>1</sup>H} Nuclear Magnetic Resonance Spectroscopy, Fourier Transform Infrared Spectroscopy, and elemental analysis was also performed to evaluate the purity of the complexes. Also, the solid state structures of complexes <strong>2d</strong> and <strong>2g</strong> have been determined by the X-ray crystallography technique. Under optimized reaction conditions, the catalytic activity of the palladium complexes was tested by direct arylation of 2-<em>n</em>-propylthiazole, 2-<em>n</em>-propylfuran, and 2-<em>n</em>-propylthiophene with various aryl halides at 120 °C for 1 h and 3 h. It was observed that palladium complexes gave high yields and were selective at the C5-position of heteroaryl derivatives. Complex <strong>2g</strong>, with an NHC N3-substituted by a 2,3,4,5,6-pentamethylbenzyl group showed the highest conversion probably due to the flexibility, the electronic and mostly the steric effects of this group.</p></div>","PeriodicalId":13599,"journal":{"name":"Inorganica Chimica Acta","volume":null,"pages":null},"PeriodicalIF":2.7000,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0020169324004468/pdfft?md5=4c96f68885784059c10fe93d82f2c984&pid=1-s2.0-S0020169324004468-main.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Inorganica Chimica Acta","FirstCategoryId":"92","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0020169324004468","RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, INORGANIC & NUCLEAR","Score":null,"Total":0}
引用次数: 0
Abstract
A series of seven 1-isopropyl-5,6-dimethylbenzimidazolium chlorides with a range of benzyl substituents on their N3 position (1a–g) were synthesized and used as NHC ligand precursors to prepare the corresponding [PdCl2(NHC)(Py)] complexes (2a–g). The structural analyses of all novel compounds were done by 1H and 13C{1H} Nuclear Magnetic Resonance Spectroscopy, Fourier Transform Infrared Spectroscopy, and elemental analysis was also performed to evaluate the purity of the complexes. Also, the solid state structures of complexes 2d and 2g have been determined by the X-ray crystallography technique. Under optimized reaction conditions, the catalytic activity of the palladium complexes was tested by direct arylation of 2-n-propylthiazole, 2-n-propylfuran, and 2-n-propylthiophene with various aryl halides at 120 °C for 1 h and 3 h. It was observed that palladium complexes gave high yields and were selective at the C5-position of heteroaryl derivatives. Complex 2g, with an NHC N3-substituted by a 2,3,4,5,6-pentamethylbenzyl group showed the highest conversion probably due to the flexibility, the electronic and mostly the steric effects of this group.
期刊介绍:
Inorganica Chimica Acta is an established international forum for all aspects of advanced Inorganic Chemistry. Original papers of high scientific level and interest are published in the form of Articles and Reviews.
Topics covered include:
• chemistry of the main group elements and the d- and f-block metals, including the synthesis, characterization and reactivity of coordination, organometallic, biomimetic, supramolecular coordination compounds, including associated computational studies;
• synthesis, physico-chemical properties, applications of molecule-based nano-scaled clusters and nanomaterials designed using the principles of coordination chemistry, as well as coordination polymers (CPs), metal-organic frameworks (MOFs), metal-organic polyhedra (MPOs);
• reaction mechanisms and physico-chemical investigations computational studies of metalloenzymes and their models;
• applications of inorganic compounds, metallodrugs and molecule-based materials.
Papers composed primarily of structural reports will typically not be considered for publication.