{6,6′-Dimethoxy-2,2′-[2,2-dimethylpropane-1,3-diylbis(nitrilomethylidyne)]diphenolato}nickel(II) 1.78-hydrate

In the title complex, [Ni(C21H24N2O4)]center dot 1.78H(2)O, the Ni-II ion has a slightly distorted planar geometry, coordinated by the two N and two O atoms of the tetradentate Schiff base ligand, with a mean deviation of 0.272 angstrom from the NiN2O2 plane. The N and O donor atoms are mutually cis. The dihedral angle between two benzene rings of the ligand is 38.86 (8)degrees. There are also three solvent water molecules, two of which lie across different crystallographic twofold rotation axes; one of these is partially occupied with a refined occupancy factor of 0.570 (7). The water molecules are linked together as tetramers in R-2(2)(8) ring motifs, which also connect two neighbouring molecules of the complex through a network of O-H center dot center dot center dot O hydrogen bonds. The crystal structure is further stabilized by intermolecular C-H center dot center dot center dot O and C-H center dot center dot center dot pi interactions, which link neighbouring molecules into extended chains along the b axis. Other interesting features of the crystal structure are the short intermolecular C center dot center dot center dot C [3.204 (3)-3.365 (3) angstrom] and the C center dot center dot center dot O [3.199 (2)-3.205 (2) angstrom] contacts which are shorter than the sum of the van der Waals radii of these atoms.