Binuclear titanocenes linked by the bridge combination of rigid and flexible segment: Synthesis and their use as catalysts for ethylene polymerization

Five novel binuclear titanocenes (CpTiCl2)2[(C5H4)CH2(p-C6H4)O(CH2)nO(C6H4-p)CH2(C5H4)] (n = 2–6) (16–20) with the bridge combination of rigid and flexible segment were synthesized and characterized. In the presence of methylaluminoxane (MAO), the behaviors of these complexes toward ethylene polymerization were investigated. The results show that their catalytic behaviors are highly dependent on the length of flexible segment and polymerization conditions. With the length of flexible segment becoming longer, the catalytic activity increases, whereas the molecular weight (MW) of the produced polyethylene (PE) decreases. In addition, the longer flexible segment is favorable to produce PE with broader molecular weight distribution (MWD).

Graphical abstractFive novel binuclear titanocenes (CpTiCl2)2[(C5H4)CH2(p-C6H4)O(CH2)nO(C6H4-p)–CH2(C5H4)] (n = 2–6) (16–20) with the bridge combination of rigid and flexible segment were synthesized. In the presence of methylaluminoxane, the behaviors of these complexes toward ethylene polymerization were investigated. The results show that their catalytic behaviors are highly dependent on the length of flexible segment and polymerization conditions.Figure optionsDownload full-size imageDownload as PowerPoint slide