Crystal structure of tetraaqua(5,5 '-dimethyl-2,2 '-bipyridyl-kappa N-2,N ')iron(II) sulfate

In the title compound, [Fe(C12H12N2)(H2O)(4)]SO4, the central Fe-II ion is coordinated by two N atoms from the 5,5-dimethyl-2,2-bipyridine ligand and four water O atoms in a distorted octahedral geometry. The Fe-O coordination bond lengths vary from 2.080 (3) to 2.110 (3) angstrom, while the two Fe-N coordination bonds have practically identical lengths [2.175 (3) and 2.177 (3) angstrom ]. The chelating N-Fe-N angle of 75.6 (1)degrees shows the largest deviation from an ideal octahedral geometry; the other coordination angles deviate from ideal values by 0.1 (1) to 9.1 (1)degrees. O-HO hydrogen bonding between the four aqua ligands of the cationic complex and four O-atom acceptors of the anion leads to the formation of layers parallel to the ab plane. Neighbouring layers further interact by means of C-HO and pi-pi interactions involving the laterally positioned bipyridine rings. The perpendicular distance between pi-pi interacting rings is 3.365(2)angstrom, with a centroid-centroid distance of 3.702 (3) angstrom.