Polymerization of methyl methacrylate catalyzed by nickel complexes with hydroxyindanone-imine ligands?

Dalton Transactions Pub Date: 2007-08-02 DOI: 10.1039/B708048D

Abstract

A series of new hydroxyindanone-imine ligands [PhN[double bond, length as m-dash]CC2H3(CH3)C6H2(CH3)OH] (HL111) and [ArN[double bond, length as m-dash]CC2H3(CH3)C6H2(R)OH] (Ar = 2,6-i-Pr2C6H3, R = Me (HL222), R = H (HL333), and R = Cl (HL444)) were synthesized and characterized. Reactions of hydroxyindanone-imines with Ni(OAc)2·4H2O result in the formation of the trinuclear hexa(indanone-iminato)tri(nickel(II)) complex Ni3[PhN[double bond, length as m-dash]CC2H3(CH3)C6H2(CH3)O]6 (1) and the mononuclear bis(indanone-iminato)nickel(II) complexes Ni[ArN[double bond, length as m-dash]CC2H3(CH3)C6H2(R)O]2 (Ar = 2,6-i-Pr2C6H3, R = Me (2), R = H (3), and R = Cl (4)). All nickel complexes were characterized by their IR, NMR spectra and elemental analyses. In addition, X-ray structure analyses were performed for complexes 1 and 2. After being activated with methylaluminoxane (MAO), these nickel(II) complexes can be used as catalysts for the polymerization of methyl methacrylate (MMA) to produce syndiotactic-rich PMMA. Catalytic activities and the degree of syndiotacticity of PMMA have been investigated for various reaction conditions.

Graphical abstract: Polymerization of methyl methacrylate catalyzed by nickel complexes with hydroxyindanone-imine ligands
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