{6,6'-Dimeth-oxy-2,2'-[2,2-dimethyl-propane-1,3-diylbis(nitrilo-methyl-idyne)]diphenolato}nickel(II) 1.78-hydrate

In the title complex, [Ni(C(21)H(24)N(2)O(4))]·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 tetra-dentate Schiff base ligand, with a mean deviation of 0.272 Å from the NiN(2)O(2) plane. The N and O donor atoms are mutually cis. The dihedral angle between two benzene rings of the ligand is 38.86 (8)°. There are also three solvent water mol-ecules, 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 mol-ecules are linked together as tetra-mers in R(2) (2)(8) ring motifs, which also connect two neighbouring mol-ecules of the complex through a network of O-H⋯O hydrogen bonds. The crystal structure is further stabilized by inter-molecular C-H⋯O and C-H⋯π inter-actions, which link neighbouring mol-ecules into extended chains along the b axis. Other inter-esting features of the crystal structure are the short inter-molecular C⋯C [3.204 (3)-3.365 (3) Å] and the C⋯O [3.199 (2)-3.205 (2) Å] contacts which are shorter than the sum of the van der Waals radii of these atoms.