New tripodal iminophosphorane-based ethylene oligomerization catalysts

• Published in: Journal of molecular catalysis. A, Chemical Chemical, 2008-03, Vol.283 (1), p.77-82
• Main Authors: Beaufort, Laurence, Benvenuti, Federica, Delaude, Lionel, Noels, Alfred F.
• Format: Article
• Language: English
• Subjects: Cu complexes; Fe complexes; Ni complexes; Pd complexes; Tripodal ligand
• ISSN: 1381-1169; 1873-314X
• DOI: 10.1016/j.molcata.2007.12.012

Seven transition-metal complexes based on new tripodal iminophosphorane ligands were investigated as initiators for the oligomerization of ethylene in the presence of aluminum co-catalysts using high-throughput techniques. Structural modifications, either at the metal center or within the tripodal ligand, did not markedly affect the catalytic activity but had a significant impact on the oligomer distribution. ▪ Seven transition-metal complexes of general formula RC ( C H 2 NP ⁡ R ′ 3 ) 3 ) M X 2 based on new tripodal iminophosphorane ligands were investigated as initiators for the oligomerization of ethylene in the presence of aluminum co-catalysts using high-throughput techniques. In all cases, ethylene consumption peaked at ca. 30 °C and was not drastically affected by varying the nature of the metal (M = Ni, Fe, Pd, Cu), the aluminum co-catalyst (MMAO, Et 2AlCl, or EtAlCl 2) or the substituents of the tris(iminophosphorane) ligand (R = Me, Ph; R′ = cyclopentyl, Ph). Structural modifications of the organometallic complexes, either at the metal center or within the tripodal ligand, however, had a significant impact on the oligomer distribution obtained. In particular, Pd-based catalyst (PhC(CH 2NPPh 3) 3)PdCl 2 displayed an excellent selectivity toward hexene formation.