Synthesis, Crystal Structure, Magnetic Properties, and EPR of Cu(bp3ca)Br2·H2O (bp3ca =
2,2‘-Bipyridine-3,3‘-dicarboxylic Acid). Ferromagnetic Interactions via Unsymmetrical
Bromide Bridges
posted on 1997-09-24, 00:00authored bySindhu Menon, M. V. Rajasekharan, J.-P. Tuchagues
Cu(bp3ca)Br2·H2O
crystallizes in the triclinic space group P1̄ with
a = 10.622(2) Å, b = 10.832(2) Å,
c =
14.684(2) Å, α = 106.13(1)°, β =
105.91(1)°, γ = 102.74(1)°, and Z = 2.
The asymmetric unit consists of a bis
μ-bromo unsymmetrically dibridged dimer which is further linked to
its inversion-related partner to form a dimer
of dimers. Weak intertetramer contacts are also observed. The
magnetic data for this compound were fit to a
linear tetramer model to give J1 =
J3 = −8.69 ×
10-3 cm-1,
J2 = 91.52 cm-1, and
the intertetramer interaction
J‘ = −1.187 cm-1 with
g = 1.93. EPR data are consistent with the magnetic
data. This system is compared to
its previously reported chloro counterpart, which differs markedly in
both structure and magnetic properties.