Dinuclear mesogens with antiferromagnetic properties.
Herein, two new groups of isomeric bimetallic nickel(II) and copper(II) complexes containing pyrazine or pyrimidine rings are synthesized and examined. The complexes exhibit liquid-crystalline columnar phases in a broad temperature range. For the copper(II) complexes, super-exchange coupling between two Cu(II) ions is observed. For the pyrimidine derivative in which the paramagnetic Cu(II) ions are separated only by three atoms, an antiferromagnetic spin alignment is detected. When the distance between Cu(II) ions increases to four atoms in the pyrazine derivative, the magnetic interaction becomes significantly weaker.
Department of Chemistry, University of Warsaw, Al. Zwirki i Wigury 101, 02-089 Warsaw, Poland.
Jadwiga
J
Szydłowska
Adam
A
Krówczyński
Damian
D
Pociecha
Jacek
J
Szczytko
Paweł
P
Budzowski
Andrzej
A
Twardowski
Ewa
E
Górecka