Francis K. Migwi, George S. Nyamato, Stephen O. Ojwach
{"title":"Dinuclear Benzene Linker Bis(pyrazolyl)amine Cobalt(II) Complexes and their Application as Selective Ethylene Dimerization Catalysts","authors":"Francis K. Migwi, George S. Nyamato, Stephen O. Ojwach","doi":"10.1002/ejic.202500204","DOIUrl":null,"url":null,"abstract":"<p>Reactions of synthons <i>N</i>,<i>N′</i>-(1,4-phenylenebis(methylene))bis(2-(1<i> H</i>-pyrazol-1-yl)ethan-1-amine) (<b>L1)</b>, <i>N</i>,<i>N</i>′-(1,4-phenylenebis(methylene))bis(2-(3,5-dimethyl-1<i> H</i>-pyrazol-1-yl)ethan-1-amine) (<b>L2)</b>, <i>N</i>,<i>N</i>′-(1,4-phenylenebis(methylene))bis(2-(3,5-di-<i>tert</i>-butyl-1<i> H</i>-pyrazol-1-yl)ethan-1-amine) (<b>L3)</b>, and <i>N</i>,<i>N</i>′-(1,3-phenylenebis(methylene))bis(2-(3,5-dimethyl-1<i> H</i>-pyrazol-1-yl)ethan-1-amine) (<b>L4)</b> with CoCl<sub>2</sub> produce the dinuclear cobalt(II) complexes [Co<sub>2</sub>(<b>L1</b>)Cl<sub>4</sub>] (<b>Co1</b>), [Co<sub>2</sub>(<b>L2</b>)Cl<sub>4</sub>] (<b>Co2</b>), [Co<sub>2</sub>(<b>L3</b>)Cl<sub>4</sub>] (<b>Co3</b>), and [Co<sub>2</sub>(<b>L4</b>)Cl<sub>4</sub>] (<b>Co4</b>), respectively. These new complexes are characterized using fourier transform-infra red and ultra-violet (UV)–Visible spectroscopies, elemental analysis, and single crystal X-ray crystallography diffraction for complexes <b>Co2</b> and <b>Co3</b>. The molecular structures of <b>Co2</b> and <b>Co3</b> confirm the formation of the dinuclear cobalt species. Activation of the precatalysts <b>Co1</b>–<b>Co4</b> with either EtAlCl<sub>2</sub> or Me<sub>3</sub>Al, affords active (up to 5.26 × 10<sup>5</sup> g·mol<sup>−1</sup>Co h<sup>−1</sup>) and selective ethylene dimerization (>98%) catalysts. The steric parameters of the coordinated ligands, as dictated by the substituents on the pyrazolyl ring, largely controll both the activity and regioselectivity of the resultant catalysts.</p>","PeriodicalId":38,"journal":{"name":"European Journal of Inorganic Chemistry","volume":"28 22","pages":""},"PeriodicalIF":2.0000,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://chemistry-europe.onlinelibrary.wiley.com/doi/epdf/10.1002/ejic.202500204","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"European Journal of Inorganic Chemistry","FirstCategoryId":"1","ListUrlMain":"https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/ejic.202500204","RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"CHEMISTRY, INORGANIC & NUCLEAR","Score":null,"Total":0}
引用次数: 0
Abstract
Reactions of synthons N,N′-(1,4-phenylenebis(methylene))bis(2-(1 H-pyrazol-1-yl)ethan-1-amine) (L1), N,N′-(1,4-phenylenebis(methylene))bis(2-(3,5-dimethyl-1 H-pyrazol-1-yl)ethan-1-amine) (L2), N,N′-(1,4-phenylenebis(methylene))bis(2-(3,5-di-tert-butyl-1 H-pyrazol-1-yl)ethan-1-amine) (L3), and N,N′-(1,3-phenylenebis(methylene))bis(2-(3,5-dimethyl-1 H-pyrazol-1-yl)ethan-1-amine) (L4) with CoCl2 produce the dinuclear cobalt(II) complexes [Co2(L1)Cl4] (Co1), [Co2(L2)Cl4] (Co2), [Co2(L3)Cl4] (Co3), and [Co2(L4)Cl4] (Co4), respectively. These new complexes are characterized using fourier transform-infra red and ultra-violet (UV)–Visible spectroscopies, elemental analysis, and single crystal X-ray crystallography diffraction for complexes Co2 and Co3. The molecular structures of Co2 and Co3 confirm the formation of the dinuclear cobalt species. Activation of the precatalysts Co1–Co4 with either EtAlCl2 or Me3Al, affords active (up to 5.26 × 105 g·mol−1Co h−1) and selective ethylene dimerization (>98%) catalysts. The steric parameters of the coordinated ligands, as dictated by the substituents on the pyrazolyl ring, largely controll both the activity and regioselectivity of the resultant catalysts.
期刊介绍:
The European Journal of Inorganic Chemistry (2019 ISI Impact Factor: 2.529) publishes Full Papers, Communications, and Minireviews from the entire spectrum of inorganic, organometallic, bioinorganic, and solid-state chemistry. It is published on behalf of Chemistry Europe, an association of 16 European chemical societies.
The following journals have been merged to form the two leading journals, European Journal of Inorganic Chemistry and European Journal of Organic Chemistry:
Chemische Berichte
Bulletin des Sociétés Chimiques Belges
Bulletin de la Société Chimique de France
Gazzetta Chimica Italiana
Recueil des Travaux Chimiques des Pays-Bas
Anales de Química
Chimika Chronika
Revista Portuguesa de Química
ACH—Models in Chemistry
Polish Journal of Chemistry
The European Journal of Inorganic Chemistry continues to keep you up-to-date with important inorganic chemistry research results.