Syntheses and structures of titanium complexes having O,N,O-tridentate ligands and their catalytic ability for ethylene polymerization

O,N,O-tridentate ligands 2-H2 based on a 2,6-substituted pyridine structure and their dichlorotitanium complexes 3 were synthesized and structurally characterized. The complexes have five-coordinated, trigonal bipyramidal structure, in which one chlorine atom was located at trans-position to the nitrogen atom of the pyridine ring and the other was at cis-position. NMR spectroscopy indicated their fluxional structure in solution. The complexes showed low to modest catalytic activity for ethylene polymerization in the presence of methylaluminoxane (MAO) as a co-catalyst.

Graphical abstractDichlorotitanium complexes 3 that have O,N,O-tridentate ligands based on a 2,6-substituted pyridine were synthesized and structurally characterized. The complexes have five-coordinated, trigonal bipyramidal structure. The complexes showed modest catalytic activity for ethylene polymerization in the presence of methylaluminoxane.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Titanium complexes that have O,N,O-tridentate ligands were synthesized. ► The ligands are based on a 2,6-substituted pyridine structure. ► The complexes showed trigonal bipyramidal structure. ► The complexes showed catalytic activity for ethylene polymerization with MAO.