Improvement in Titanium Complexes Bearing Schiff Base Ligands in the Ring-Opening Polymerization of L-Lactide: A Dinuclear System with Hydrazine-Bridging Schiff Base Ligands

Inorganic Chemistry
Hsi-Ching TsengHsuan-Ying Chen

Abstract

A series of titanium (Ti) complexes bearing hydrazine-bridging Schiff base ligands were synthesized and investigated as catalysts for the ring-opening polymerization (ROP) of L-lactide (LA). Complexes with electron withdrawing or steric bulky groups reduced the catalytic activity. In addition, the steric bulky substituent on the imine groups reduced the space around the Ti atom and then reduced LA coordination with Ti atom, thereby reducing catalytic activity. All the dinuclear Ti complexes exhibited higher catalytic activity (approximately 10-60-fold) than mononuclear L(Cl-H)-TiOPr2 did. The strategy of bridging dinuclear Ti complexes with isopropoxide groups in the ROP of LA was successful, and adjusting the crowded heptacoordinated transition state by the bridging isopropoxide groups may be the key to our successful strategy.

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Citations

May 18, 2016·Inorganic Chemistry·Alexandre B KremerParisa Mehrkhodavandi
Oct 27, 2017·Dalton Transactions : an International Journal of Inorganic Chemistry·Antonio OteroAna M Rodríguez
May 26, 2016·Dalton Transactions : an International Journal of Inorganic Chemistry·Yingguo LiJincai Wu
Aug 12, 2016·Dalton Transactions : an International Journal of Inorganic Chemistry·Florence IsnardMina Mazzeo
Jun 8, 2018·Dalton Transactions : an International Journal of Inorganic Chemistry·Yong HuangYing Yang

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