Aminopyridinate-FI Hybrids, Their Hafnium and Titanium Complexes, and Their Application in the Living Polymerization of 1-Hexene

作者：Haas Isabelle; Dietel Thomas; Press Konstantin; Kol Moshe^*; Kempe Rhett

来源：Chemistry - A European Journal, 2013, 19(42): 14254-14262.

DOI：10.1002/chem.201301511

• hafnium
• ligand design
• ligand effects
• living polymerization
• polymerization

Based on two well-established ligand systems, the aminopyridinato (Ap) and the phenoxyimine (FI) ligand systems, new Ap-FI hybrid ligands were developed. Four different Ap-FI hybrid ligands were synthesized through a simple condensation reaction and fully characterized. The reaction of hafnium tetrabenzyl with all four Ap-FI hybrid ligands exclusively led to mono(Ap-FI) complexes of the type [(Ap-FI)HfBn2]. The ligands acted as tetradentate dianionic chelates. Upon activation with tris(pentafluorophenyl)borane, the hafnium-dibenzyl complexes led to highly active catalysts for the polymerization of 1-hexene. Ultrahigh molecular weights and extremely narrow polydispersities support the living nature of this polymerization process. A possible deactivation product of the hafnium catalysts was characterized by single-crystal X-ray analysis and is discussed. The coordination modes of these new ligands were studied with the help of model titanium complexes. The reaction of titanium(IV) isopropoxide with ligand 1 led to a mono(Ap-FI) complex, which showed the desired fac-mer coordination mode. Titanium (IV) isopropoxide reacted with ligand 4 to give a complex of the type [(ApH-FI)(2)Ti(OiPr)(2)], which featured the ligand in its monoanionic form. The two titanium complexes were characterized by X-ray crystal-structure analysis.

• 出版日期2013-10-11