ic049252h_si_002.pdf (16.5 kB)
Targeted Ferromagnetic Coupling in a Trinuclear Copper(II) Complex: Analysis of the St = 3/2 Spin Ground State
journal contribution
posted on 2004-08-23, 00:00 authored by Thorsten Glaser, Maik Heidemeier, Stefan Grimme, Eckhard BillThe trinuclear CuII complex [(talen)CuII3] (1) using the new
triplesalen ligand H6talen has been synthesized and structurally
characterized. The three CuII ions are bridged in a m-phenylene
linkage by the phloroglucinol backbone of the ligand. This
m-phenylene bridging mode results in ferromagnetic couplings with
an St = 3/2 spin ground state, which has been analyzed by means
of EPR spectroscopy and DFT calculations. The EPR spectrum
exhibits an unprecedented pattern of 10 hyperfine lines due to
the coupling of three CuII ions (I = 3/2). Resonances around g =
4 in both perpendicular and parallel mode EPR spectra demonstrate
a zero-field splitting of D ∼ 74 × 10-4 cm-1 arising from
anisotropic/antisymmetric exchange interactions. The DFT calculations show an alteration in the sign of the spin densities of the
central benzene ring corroborating the spin-polarization mechanism
as origin for the ferromagnetic coupling.