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Synthesis and characterization of Ni(II) complexes bearing of 2‐(1 H –benzimidazol‐2‐yl)‐phenol derivatives as highly active catalysts for ethylene oligomerization
Author(s) -
Haghverdi Marzieh,
Tadjarodi Azadeh,
BahriLaleh Naeimeh,
NekoomaneshHaghighi Mehdi
Publication year - 2018
Publication title -
applied organometallic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 71
eISSN - 1099-0739
pISSN - 0268-2605
DOI - 10.1002/aoc.4015
Subject(s) - chemistry , trimer , ligand (biochemistry) , catalysis , substituent , steric effects , denticity , guaiacol , medicinal chemistry , dimer , ethylene , selectivity , inorganic chemistry , stereochemistry , crystallography , organic chemistry , crystal structure , biochemistry , receptor
Novel Ni(II) complexes of 2‐(1 H –benzimidazol‐2‐yl)‐phenol derivatives (HL x : x = 1–5; C1–C5 ) have been synthesized and characterized. In the mononuclear complexes, the ligands were coordinated as bidentate, via one imine nitrogen and the phenolate oxygen atoms. The structures of the compounds were confirmed on the basis of FT‐IR, UV–Vis, 1 H‐, 13 C–NMR, inductively coupled plasma and elemental analyses (C, H and N). The purity of these compounds was ascertained by melting point (m.p.) and thin‐layer chromatography. The geometry optimization and vibrational frequency calculations of the compounds were performed using Gaussian 09 program with B3LYP/TZVP level of theory. All Ni(II) complexes were activated with diethylaluminum chloride (Et 2 AlCl), so that C2 showed the highest activity [6600 kg mol −1 (Ni) h −1 ], where the ligand contains a chlorine substituent. Oligomers obtained from the complexes consist mainly of dimer and trimer, and also exhibit high selectivity for linear 1‐butene and 1‐hexene. Both the steric and electronic effects of coordinative ligands affect the catalytic activity and the properties of the catalytic products.