Magnetic properties of the octahedral chromium chalcogenide cluster complexes [Cr6Se8(PEt3)(6)], [Cr6Se8(H)(PEt3)(6)], and [Cr6S8(H)(PEt3)(6)]

The magnetic data of chromium chalcogenide cluster complexes [Cr6Se8(PEt3)( 6)] (1), [Cr6Se8(H)(PEt3)(6)] (2), and [Cr6S8(H)(PEt3)(6)] (3) have been an alyzed using the Heisenberg-Dirac-Van Vleck Hamiltonian. The analysis has s hown that all of these complexes display an antiferromagnetic interaction b etween chromium atoms and that the coupling constants decrease in the order 2 > 3 > 1. This interaction is mediated by Cr-(mu (3)-E)-Cr bridges (E = S e, S) and Cr-Cr bonds. In a comparison of the two hydride clusters, the sel enide 2 has a larger antiferromagnetic coupling than the sulfide 3. The sho rter Cr-Cr distances in 2 (mean 2.66 Angstrom) than those in 1 (mean 2.81 A ngstrom) seem to cause larger antiferromagnetic interaction through the Cr- Cr bonds.