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Metallopolymers with Schiff Base Side Chains. Synthesis and Characterization of Some Nickel(II) Containing Polymers with Unexpected Cooperative Magnetic Properties
Author(s) -
Werner Rüdiger,
Falk Karsten,
Ostrovsky Sergei,
Haase Wolfgang
Publication year - 2001
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/1521-3935(20011001)202:14<2813::aid-macp2813>3.0.co;2-t
Subject(s) - nickel , polymer , magnetization , ferromagnetism , magnetic susceptibility , schiff base , side chain , monomer , materials science , polymer chemistry , curie temperature , crystallography , chemistry , magnetic field , physics , condensed matter physics , composite material , metallurgy , quantum mechanics
The synthesis of a novel series of nickel containing crosslinked metallopolymers has been developed. Nickel(II) is complexed by Schiff base units as part of a mesogenic side chain polymer. Several polymers with different lengths of their aliphatic tails were used. The degree of complexation is in all cases very high which allows the nickel ions of neighbored side chains to order in linear chains. This leads to remarkable ferromagnetic exchange interactions between the nickel centers which are not present in related monomeric model compounds. Elemental analyses, IR‐spectroscopic investigations in the region 4 000–400 cm –1 , and temperature dependent magnetic susceptibility measurements were carried out to elucidate the structures of these new materials. Fitting the magnetic data to a linear chain model gives exchange constants J between 1 and 8 cm –1 . AC‐susceptibility and magnetization measurements show that 4 of the 8 samples exhibit cooperative magnetic properties with Curie temperatures between 9 and 15 K, coercitivities up to 590 G and remnant magnetization up to 860 emuG/mol.