Issue 18, 2017

Aluminum complexes derived from a hexadentate salen-type Schiff base: synthesis, structure, and catalysis for cyclic carbonate synthesis

Abstract

Different aluminum complexes were synthesized by the reaction of aluminum alkyls with a hexadentate salen-type Schiff base. The reaction of N,N′-bis(3,5-di-tert-butylsalicylidene)-2,2′-(ethylenedioxy)dianiline (LH2) with one equiv. of AlMe3 in toluene at 100 °C proceeded by methane elimination to produce the intermediate methyl complex [AlMeL] (1), and then subsequent intramolecular methyl migration to give the aluminum complex [AlL′] (2) [L′ = (2-O-3,5-tBu2C6H2)CH[double bond, length as m-dash]NC6H4OCH2CH2OC6H4NCH(Me)(2′-O-3′,5′-tBu2C6H2)]. The reaction of the same ligand with AlEt3 under the same experimental conditions involved ethane elimination, ethylene elimination and intramolecular hydrogen migration, and led to the complex [AlL′′] (3) [L′′ = (2-O-3,5-tBu2C6H2)CH[double bond, length as m-dash]NC6H4OCH2CH2OC6H4NCH2(2′-O-3′,5′-tBu2C6H2)]. However, the interaction of two equivalents of AlMe3 and AlEt3 afforded the corresponding binuclear complexes [(AlMe2)2L] (4) and [(AlEt2)2L] (5), respectively, and no methyl or hydrogen migration was found. The solid-state structures of aluminum complexes 1–3 were determined by single-crystal X-ray diffraction. It was found that complexes 2–5 show a very effective catalytic activity for the cycloaddition of epoxides and CO2 in the presence of NBu4Br as a cocatalyst at atmospheric pressure.

Graphical abstract: Aluminum complexes derived from a hexadentate salen-type Schiff base: synthesis, structure, and catalysis for cyclic carbonate synthesis

Supplementary files

Article information

Article type
Paper
Submitted
04 Mar 2017
Accepted
27 Mar 2017
First published
28 Mar 2017

Dalton Trans., 2017,46, 5848-5855

Aluminum complexes derived from a hexadentate salen-type Schiff base: synthesis, structure, and catalysis for cyclic carbonate synthesis

Y. Xu, D. Yuan, Y. Wang and Y. Yao, Dalton Trans., 2017, 46, 5848 DOI: 10.1039/C7DT00789B

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements