Ferromagnetic oxovanadium(IV) complexes chelated with tetrahalosalen ligands

Five oxovanadium(IV) complexes [VO(X4salen)] have been prepared and characterized, where each benzene ring was substituted with two halogen atoms in salen (H2salen = N,N′-disalicylideneethylenediamine). The X-ray diffraction study on 3,3′,5,5′-tetrachloro-, 3,3′,5,5′-tetrabromo-, and 4,4′,6,6′-tetrachlorosalen derivatives clarified their polymeric structure with the (–VO–)n repeating unit. The interatomic V···V distances are 3.710(3), 3.695(3), and 3.749(3) Å, respectively, being shorter than that of known [VO(salpn)] (3.83 Å; H2salpn = N,N′-disalicylidenepropylenediamine). The exchange coupling parameters (J) were determined by fitting the magnetic susceptibility data to the one-dimensional ferromagnetic model, giving 2J/kB = 8.2–16 K, which are the largest in the [VO(salen)] and [VO(salpn)] family.

Five oxovanadium(IV) complexes [VO(X4salen)] have been prepared and characterized. The exchange coupling parameters (J) were determined by fitting the magnetic susceptibility data to the one-dimensional ferromagnetic model, giving 2J/kB = 8.2–16 K, which are the largest in the [VO(salen)] and [VO(salpn)] family.Figure optionsDownload as PowerPoint slideHighlights
► All of the present compounds are ferromagnetic.
► The introduction of halogen atoms improves the intimate 1-D structure.
► The V···V distances are the shortest in the [VO(salen)] and [VO(salpn)] family.
► The largest exchange couplings are thus obtained.