Ferromagnetic exchange in a twisted, oxime-bridged [Mn(III)2] dimer.
The dimeric complex [Mn(III)(2)(Naphth-sao)(2)(Naphth-saoH)(2)(MeOH)(2)]·4MeOH (1·4MeOH), acts as a simple model complex with which to examine the magneto-structural relationship in polymetallic, oxime-bridged Mn(III) complexes. Dc magnetic susceptibility studies reveal that ferromagnetic exchange is mediated through the heavily twisted Mn-O-N-Mn moiety (J = +1.24 cm(-1)) with magnetisation measurements at low temperatures and high fields suggesting significant anisotropy. Simulations of high field, high frequency EPR data reveal a single ion anisotropy, D((Mn(III))) = -3.94 cm(-1). Theoretical studies on simplified model complexes of 1 reveal that calculated values of the exchange coupling and the anisotropy are in excellent agreement with experiment, with the weak ferromagnetism resulting from an accidental orthogonality between the Mn-N-O plane of the first Mn(III) ion and the Jahn-Teller axis of the second Mn(III) ion.
School of Chemistry, NUI Galway, University Road, Galway, Ireland.
Edel
E
Houton
Stephanie M
SM
Taylor
Christopher C
CC
Beedle
Joan
J
Cano
Stergios
S
Piligkos
Stephen
S
Hill
Alan G
AG
Ryder
Euan K
EK
Brechin
Leigh F
LF
Jones