Iron and cobalt salicylaldimine complexes as catalysts for epoxide and carbon dioxide coupling: effects of substituents on catalytic activity
详细信息 查看全文
- 作者：Adnan S. Abu-Surrah ; Hamzeh M. Abdel-Halim…
- 刊名：Transition Metal Chemistry
- 出版年：2017
- 出版时间：March 2017
- 年：2017
- 卷：42
- 期：2
- 页码：117-122
- 全文大小：
- 刊物类别：Chemistry and Materials Science
- 刊物主题：Catalysis; Physical Chemistry; Inorganic Chemistry; Organometallic Chemistry;
- 出版者：Springer International Publishing
- ISSN：1572-901X
- 卷排序：42
文摘
The synthesis and characterization of substituted ONNO-donor salen-type Schiff base complexes of general formula [MIII(L)Cl] (L = Schiff base ligand, M = Fe, Co) is reported. The complexes have been applied as catalysts for the coupling of carbon dioxide and styrene oxide in the presence of tetrabutylammonium bromide as a co-catalyst. The reactions were carried out under relatively low-pressure and solvent-free conditions. The effects of the metal center, ligands, and various substituents on the peripheral sites of the ligand on the coupling reaction were investigated. The catalyst systems were found to be selective for the coupling of CO2 and styrene oxide, resulting in cyclic styrene carbonate. The cobalt(III) complex with no substituents on the ligand showed higher activity (TON = 1297) than the corresponding iron(III) complex (TON = 814); however, the iron(III)-based catalysts bearing electron-withdrawing substituents on the salen ligands (NEt3, TON = 1732) showed the highest catalytic activity under similar reaction conditions. The activity of one of the cobalt(III) complexes toward the coupling of 1-butene oxide, cyclohexene oxide and propylene oxide with CO2 was evaluated, revealing a notable activity for the coupling of 1-butene oxide.