A new asymmetrically coordinated bis-trinuclear iron(III) cluster containing a {Fe
3O}
7+ core has been synthesizedand structurally, magnetically, and spectroscopically characterized. [Fe
6Na
2O
2(O
2CPh)
10(pic)
4(EtOH)
4(H
2O)
2](ClO
4)
2·2
tOH (
1·2
tOH) crystallizes in the
P space group and consists of two symmetry-related {Fe
3O}
7+ subunitslinked by two Na
+ cations. Inside each {Fe
3O}
7+ subunit, the iron(III) ions are antiferromagnetically coupled, andtheir magnetic exchange is best described by an isosceles triangle model with two equal (
J) and one different (
J ')coupling constants. On the basis of the
H = -2
JijSiSj spin Hamiltonian formalism, the two best fits to the datayield solutions
J = -27.4 cm
-1,
J ' = -20.9 cm
-1 and
J = -22.7 cm
-1,
J ' = -31.6 cm
-1. The ground state ofthe cluster is
S =
1/
2. X-band electron paramagnetic resonance (EPR) spectroscopy at liquid-helium temperaturereveals a signal comprising a sharp peak at
g ~ 2 and a broad tail at higher magnetic fields consistent with the
S =
1/
2 character of the ground state. Variable-temperature zero-field and magnetically perturbed Mössbauer spectraat liquid-helium temperatures are consistent with three antiferromagnetically coupled high-spin ferric ions in agreementwith the magnetic susceptibility and EPR results. The EPR and Mössbauer spectra are interpreted by assumingthe presence of an antisymmetric exchange interaction with
d ~ 2-4 cm
-1 and a distribution of exchange constants
Jij.