Issue 1, 2015

Dinuclear nickel(ii) complexes with 2,5-diamino-1,4-benzoquinonediimine ligands as precatalysts for the polymerization of styrene: electronic and steric substituent effects

Abstract

Catalytic polymerization of styrene with a series of dinuclear nickel(II) complexes [{Ni(acac)}2{μ-C6H2-(N-Ph-R)4}] (R = 4-Et (1a), 4-OEt (1b), 2-OEt (1c), 2-Et (1d), and 2,6-Et2 (1e)) in the presence of methylaluminoxane was studied under various conditions to evaluate the substituent effect. The activity of 1a–1e, except 1c, increased with an increase in the reaction temperature, and the highest activity (7.46 × 105 g PS mol−1 Ni h−1) was obtained using 1e at 70 °C. The electronic and steric properties of the ligand influenced the activity at room temperature, 50 °C, and 60 °C, steric factors barely, whereas electronic factors slightly dominated the activity at 70 °C. The activity with 1c remained constant at all temperatures, probably due to the masking of the active center by the formation of inactive N,N′,O-chelate species. The obtained polymers were atactic polystyrenes with molecular weights and molecular weight distributions in the range of 15 000–43 400 and 1.71–2.14, respectively. While a clear dependence of the molecular weight and molecular weight distribution on the temperature was observed, no significant dependence on the substituent was noted.

Graphical abstract: Dinuclear nickel(ii) complexes with 2,5-diamino-1,4-benzoquinonediimine ligands as precatalysts for the polymerization of styrene: electronic and steric substituent effects

Supplementary files

Article information

Article type
Paper
Submitted
17 Sep 2014
Accepted
17 Oct 2014
First published
10 Nov 2014

Dalton Trans., 2015,44, 368-376

Author version available

Dinuclear nickel(II) complexes with 2,5-diamino-1,4-benzoquinonediimine ligands as precatalysts for the polymerization of styrene: electronic and steric substituent effects

K. Ohno, A. Nagasawa and T. Fujihara, Dalton Trans., 2015, 44, 368 DOI: 10.1039/C4DT02858A

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