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Synthesis of N , N ′, X ‐tridentate 2‐iminomethylpyrrole‐coordinated palladium(II) complexes via N─H bond activation of pyrrole moiety
Author(s) -
Kim Dongil,
Seo Jaeyoung,
Nayab Saira,
Lee Hyosun
Publication year - 2017
Publication title -
applied organometallic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 71
eISSN - 1099-0739
pISSN - 0268-2605
DOI - 10.1002/aoc.3780
Subject(s) - chemistry , moiety , methylene , palladium , methylaluminoxane , diamine , medicinal chemistry , monomer , amine gas treating , methyl methacrylate , polymer chemistry , stereochemistry , polymerization , metallocene , catalysis , organic chemistry , polymer
The reaction of [Pd(CH 3 CN) 2 Cl 2 ] with N ‐functional group‐substituted 2‐iminomethylpyrrole‐based ligands, namely N 1 ‐((1H‐pyrrol‐2‐yl)methylene)‐ N 3 , N 3 ‐dimethylpropane‐1,3‐diamine (L A ), N 1 ‐((1H‐pyrrol‐2‐yl)methylene)‐ N 3 ‐methyl‐ N 3 ‐phenylpropane‐1,3‐diamine (L B ), N ‐((1H‐pyrrol‐2‐yl)methylene)‐3‐(methylthio)propan‐1‐amine (L C ) and N ‐((1H‐pyrrol‐2‐yl)methylene)‐3‐methoxypropan‐1‐amine (L D ), resulted in [L n PdCl] (L n = L A –L D ) complexes in high yield via N─H bond activation of pyrrole moiety without use of base. [L n PdCl] existed as monomeric four‐coordinated complexes with slightly distorted square planar geometries around the palladium metal center. The ligands show N , N ′, X ‐tridentate binding mode to the palladium metal center to give two fused ring metallacycles. [L B PdCl] gave the highest activity (3.29 × 10 5 g PMMA (mol Pd) −1 h −1 ) for a methyl methacrylate (MMA) polymerization in the presence of modified methylaluminoxane at 60 °C compared to the other Pd(II) analogues, and resulted in PMMA with higher molecular weight ( M w = 7.16 × 10 5 g mol −1 ) and narrower polydispersity index. Syndiotactic‐enriched PMMA resulted in all cases.