Abstract of Publication No. 524
Andreas Sieber, Dolos Foguet-Albiol, Oliver Waldmann, Stefan T. Ochsenbein, Roland Bircher,
George Christou, Felix Fernandez-Alonso, Hannu Mutka and Hans U. Güdel
Energy splittings resulting from anisotropy and exchange interactions in the
dimer of single-molecule magnets
are determined for both an undeuterated and a partially deuterated sample using
inelastic neutron scattering. The antiferromagnetic (AF) exchange coupling
between the two Mn4 subunits strongly depends on their separation.
The Cl···Cl distance between the two subunits can be modified either by
exchanging the solvent of crystallization or by deuteration of the C-H···Cl
hydrogen bonds. The exchange of acetonitrile for n-hexane leads to a five
times greater shortening of the Cl···Cl separation than does full deuteration of
all the hydrogen bonds. As a result, the AF exchange coupling constants between
the subunits are 0.0073(4) and 0.0103(9) meV in the samples with acetonitrile
and n-hexane solvent molecules, respectively, in the crystal structure.
On the other hand, the effect of C-H···Cl deuteration on the AF exchange
coupling is not detectable within the experimental accuracy of INS.