Palladium(II) complexes containing N,N′-bidentate N-(pyridin-2-ylmethyl)aniline and its derivatives: Synthesis, structural characterisation, and methyl methacrylate polymerisation

The reaction of [Pd(CH3CN)2Cl2] with N-(pyridin-2-ylmethyl)aniline (L1) and its derivatives (L2–L6) in ethanol yields [(NN′)PdCl2] complexes, namely [LnPdCl2] (Ln = L1–L6). The X-ray crystal structure of Pd(II) complexes revealed that the palladium atom in [LnPdCl2] (Ln = L1–L6) showed a square plane geometry involving two nitrogen atoms of NN′-bidentate and two chlorido ligands. Complex [L4PdCl2] containing 2,4,6-trimethyl-N-(pyridin-2-ylmethyl)aniline (L4) showed the highest catalytic activity for the polymerisation of methyl methacrylate (MMA) in the presence of modified methylaluminoxane (MMAO) with an activity of 1.41 × 105 g PMMA/mol Pd·h at 60 °C and poly(methyl methacrylate) (PMMA) syndiotacticity (characterised using 1H NMR spectroscopy) of ca. 0.70.

Complexes [LnPdCl2] (Ln = L1–L6), for example L1 is N-(pyridin-2-ylmethyl)aniline, were synthesized and characterized by X-ray crystallography. It showed that the co-ordination geometry around the palladium center was slightly distorted square-planar. The catalytic activity of MMA polymerisation by [L4PdCl2] (L4 = 2,4,6-trimethyl-N-(pyridin-2-ylmethyl)aniline) under MMAO was 1.41 × 105 g PMMA/mol Pd.h with 70% conversion of MMA to PMMA.Figure optionsDownload as PowerPoint slide