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Upstream product

• 55137-80-9 2,6-bis{1-(phenylimino)ethyl}pyridine 
• 70317-90-7 FeCl₂(THF)2 

Relevant academic research and scientific papers

New iron-based bis(imino)pyridine and acetyliminopyridine complexes as single-site catalysts for the oligomerization of ethylene

New Fe-based bis(imino)pyridine complexes 6,7 and the acetyliminopyridine complex 8a are active catalysts together with the co-catalyst MAO for the oligomerization of ethylene. The influence of electron donating methoxy- and electron withdrawing trifluoromethyl-groups attached to the imino phenyl substituents was tested in the catalysis. The bis(imino)pyridine and the acetyliminopyridine complexes 5-8a revealed differences in their behavior as precatalysts for the oligomerization of ethylene, which depended on the different electronic influence of the various substituents at the rings and on the reaction conditions. Olefins ranging from C4-C18 were produced in all experiments but the turnover numbers varied between 1000 and 43,000. Variation of the catalyst ligand, temperature, and pressure had a considerable effect on α-olefin selectivity and on the formation of the main olefin species in the products. The complexes 5-8a showed small Schulz-Flory α values, which proved a low chain propagation.

Propylene bulk phase oligomerization with bisiminepyridine iron complexes in a calorimeter: Mechanistic investigation of 1,2 versus 2,1 propylene insertion

Iron(II) complexes were synthesized with bisiminepyridine ligands of low steric demand. Activation with modified-methylaluminoxane (25 mol.% isobutyl groups) generated very active catalysts for propylene oligomerization. The oligomerizations were carried out in liquid propylene in a heat flow calorimeter. The oligomers were separated by preparative gas chromatography and the dimers and trimers analyzed using analytical gas chromatography, 1 H-NMR- and 13C-NMR-spectroscopy. With knowledge of the dimer and trimer structure, we were able to establish a mechanistic pathway for propylene insertion and obtained knowledge about the iron alkyl species involved. Analysis of the various dimers formed allowed us to determine the percentage of 1,2 versus 2,1 propylene insertions. Considering the same iron alkyl species with ligands of different steric demand, a change in the probabilities for 1,2 versus 2,1 propylene insertions can be observed. With this knowledge, the catalyst behavior for ligands of varying steric demand can be predicted.

New bis(imino)pyridine-iron(II)- and cobalt(II)-based catalysts: Synthesis, characterization and activity towards polymerization of ethylene

The synthesis of a new series of iron(II)- and cobalt(II)-based complexes of the general formula M(NONON) Cl2 (M = Fe; M = Co) bearing 2,6-bis(imin)pyridyl ligands [A-N=C-Py-C=N-A] that carry bulky, alkyl-free aromatic terminals (A = naphthyl, pyrenyl, 2-benzylphenyl, phenyl) or chiral cycloaliphatic auxiliary moieties (A = ((-)-cis-myrtanyl) is described. The Fe(II) complexes are exceptionally active (up to 40800 kg PE/(mol M h) towards the polymerization of ethylene in the presence of methylaluminoxane (MAO) as activator. Varying the steric bulkiness of the aromatic groups in the tridentate ligands affects catalytic productivity, molecular weight and for the first time the microstructure of the resulted material. The Fe(II) precatalysts are an order of magnitude more active than the corresponding Co(II) precatalysts.

Heterogenized iron(II) complexes as highly active ethene polymerization catalysts

The synthesis of new iron(II) diiminopyridine complexes and their heterogenization to give highly active ethene polymerization catalysts is described. The ligands are characterized by 1H NMR, 13C NMR spectroscopy and GC/MS. The compl