  Three isostructural cyano-bridged heptanuclear complexes,
[{CuII(saldmen)(H2O)}6{MIII(CN)6}](ClO4)3$\cdotp$8H2O (M = FeIII 2; CoIII, 3;
CrIII 4), have been obtained by reacting the binuclear copper(II) complex,
[Cu2(saldmen)2(mu-H2O)(H2O)2](ClO4)2$\cdotp$2H2O 1, with K3[Co(CN)6],
K4[Fe(CN)6], and, respectively, K3[Cr(CN)6] (Hsaldmen is the Schiff base
resulted from the condensation of salicylaldehyde with
N,N-dimethylethylenediamine). A unique octameric water cluster, with
bicyclo[2,2,2]octane-like structure, is sandwiched between the heptanuclear
cations in 2, 3 and 4. The cryomagnetic investigations of compounds 2 and 4
reveal ferromagnetic couplings of the central FeIII or CrIII ions with the CuII
ions (JCuFe = +0.87 cm-1, JCuCr = +30.4 cm-1). The intramolecular Cu-Cu
exchange interaction in 3, across the diamagnetic cobalt(III) ion, is -0.3
cm-1. The solid-state1H-NMR spectra of compounds 2 and 3 have been
investigated.
