Work

Dinuclear Benzene Linker Bis(pyrazolyl)amine Cobalt(II) Complexes and their Application as Selective Ethylene Dimerization Catalysts

Year: 2025

Type: article

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.

Source: European Journal of Inorganic Chemistry

DOI: 10.1002/ejic.202500204

Authors: Francis K. Migwi, George S. Nyamato, Stephen O. Ojwach

Institutions: University of KwaZulu-Natal, University of Embu

Language: English

Topic: Organometallic Complex Synthesis and Catalysis

Subfield: Organic Chemistry

Field: Chemistry

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $4,050

Funder: National Research Foundation