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Dichloro-Bis(1-Alkyl/Styryl-Benzimidazole)-Cobalt(II) Pre-Catalyst for Ethylene Dimerization

Shaima Hkiri, Neslihan Şahin, Romain Sabourin, Rémi Brandt, İsmail Özdemir, David Sémeril

Organics · pp. 49–49 · Published 4 Nov 2025

10.3390/org6040049

Abstract

A series of five cobalt(II) complexes, dichloro-bis(1-benzyl-benzimidazole)-cobalt(II) (1a), dichloro-bis[1-(4-fluorobenzyl)-benzimidazole]-cobalt(II) (1b), dichloro-bis((Z)-1-styryl-benzimidazole)-cobalt(II) (1c), dichloro-bis[(Z)-1-(2-fluorostyryl)-benzimidazole]-cobalt(II) (1d) and dichloro-bis(1-cinnamyl-benzimidazole)-cobalt(II) (1e), were evaluated in ethylene dimerization. Four of these complexes were described for the first time and fully characterized by IR, elemental analysis, mass and NMR spectroscopy. In the solid state, the cobalt atom exhibited a typical tetrahedral geometry and was found to be coordinated to two chlorine atoms and two benzimidazole rings. In the presence of 20 bar of ethylene and diethylaluminium chloride as a co-catalyst, the complex with styryl substituents on the benzimidazole rings, complex 1c, exhibited the highest activity with a turnover frequency of 3430 mol(ethylene)·mol(Co)−1·h−1.

Ethylene Chemistry Benzimidazole Cobalt Chlorine Chlorine atom Elemental analysis Chloride

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