Abstract

The trimer [Co3(μ-OOCCF3)4(μ-H 2O)2(OOCCF3)2(H2O) 2(C4H8O2)]·2C 4H8O2 (1) is composed of three tetragonally distorted CoII centers bridged by four trifluoroacetates and two bridging water molecules. 1,4-Dioxane is coordinated at a distance of 2.120(3) Å 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 CoII, spin-orbit coupling and a low-symmetry crystal field acting within the 4T1g 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. © 2006 American Chemical Society.