Novel example of a chain structure formed by 1,4-dioxane and cobalt(II) links.: Chain [Co3(μ-OOCCF3)4(μ-H2O)2(OOCCF3)2(H2O)2(C4H8O2)]•2C4H8O2

The trimer [Co-3(mu-OOCCF3)(4)(mu-H2O)(2)(OOCCF3)(2)(H2O)(2)(C4H8O2)]center dot 2C(4)H(8)O(2) (1) is composed of three tetragonally distorted Coll centers bridged by four trifluoroacetates and two bridging water molecules. 1,4-Dioxane is coordinated at a distance of 2.120(3) angstrom from the terminal cobalt Co2; the remaining oxygen of this 1,4-dioxane links the terminal cobalt to a neighbor trimer, forming a one-dimensional chain. The crystal structure displays a network of hydrogen bonds between four noncoordinated 1,4-dioxane molecules and the coordinated terminal water molecules. The magnetic properties of 1 were analyzed with the use of the Hamiltonian including isotropic exchange interactions between real spins of a high-spin Co-parallel to, spin-orbit coupling and a low-symmetry crystal field acting within the T-4(1g) ground manifold of each cobalt ion. A weak antiferromagnetic exchange interaction between cobalt ions in 1 was found. The results of the magnetic model are in good agreement with the experimental observations.