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On the topology of highly branched polyethylenes prepared by amine−imine nickel and palladium complexes: the effect of ortho ‐aryl substituents
Author(s) -
Mundil Robert,
Hermanová Soňa,
Peschel Martin,
Lederer Albena,
Merna Jan
Publication year - 2018
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/pi.5593
Subject(s) - imine , palladium , aryl , nickel , substituent , amine gas treating , polymer chemistry , polymerization , chemistry , catalysis , topology (electrical circuits) , materials science , organic chemistry , polymer , alkyl , mathematics , combinatorics
Series of nickel and palladium complexes bearing amine−imine ligands in various ortho ‐aryl and backbone positions were prepared and investigated in ethene polymerization. Ethene polymerization initiated by symmetrically ortho ‐substituted nickel and palladium amine−imine catalysts is controlled. Mono‐substitution in the ortho ‐aryl positions of nickel complexes is not as efficient in protecting centers from chain transfer as di‐substitution. Both the central metal and the size of the ortho ‐aryl substituent have a significant effect on the polyethylene (PE) topology. Based on detailed characterization by high temperature SEC‐IR‐η, SEC with multi‐angle laser light scattering and 13 C NMR data, PEs prepared by nickel amine−imine complexes have a linear rather than dendritic topology. In contrast, palladium amine−imine complexes with small ortho ‐aryl substituents at low ethene pressure were shown for the first time to form dendritic PEs with topology comparable to PEs formed by α‐diimine palladium catalyst. © 2018 Society of Chemical Industry