{5,5′-Dimethoxy-2,2′-[1,1′-(2,2-dimethylpropane-1,3-diyldinitrilo)diethylidyne]diphenolato-κ4 O,N,N′,O′}copper(II) monohydrate

The tetradentate dianion in the title complex hydrate, [Cu(C23H28N2O4)]·H2O, provides the CuII atom with a cis-N2O2 donor set. There is a significant twist from a regular square-planar geometry with the dihedral angle formed between the two six-membered CuOC3N chelate rings being 32.14 (8)°. The water molecule forms hydrogen bonds to each of the coordinating O atoms of a given complex molecule. Supramolecular layers in the bc plane are formed in the crystal packing through C—H⋯O and C—H⋯π interactions.

The tetradentate dianion in the title complex hydrate, [Cu(C 23 H 28 N 2 O 4 )]ÁH 2 O, provides the Cu II atom with a cis-N 2 O 2 donor set. There is a significant twist from a regular square-planar geometry with the dihedral angle formed between the two six-membered CuOC 3 N chelate rings being 32.14 (8) . The water molecule forms hydrogen bonds to each of the coordinating O atoms of a given complex molecule. Supramolecular layers in the bc plane are formed in the crystal packing through C-HÁ Á ÁO and C-HÁ Á Á interactions.
The tetradentate dianion in the title monohydrate, (I), Fig. 1 two CuOC 3 N chelate rings is 32.14 (8)° indicating a significant distortion from a regular square planar geometry. Each of the methoxy groups is co-planar with the benzene ring to which it is attached as seen in the values of the C7-O1-C3-C2 and C23-O4-C20-C19 of -0.8 (4) and -179.3 (3)°, respectively. The water molecule of solvation is associated with the complex, forming a bridge via its hydrogen atoms between the two coordinated oxygen atoms, Table 2.
The crystal packing features C-H···O and C-H···π interactions, Table 2, that assemble molecules into layers in the bc plane, Fig. 2, which stack along the a axis, Fig. 3.

Experimental
The title complex was obtained by the template method in a branch tube (Harrowfield et al., 1996). The recently described (Ghaemi et al., 2011) N,N'-bis(2-hydroxy-4-methoxyacetophenone)-2,2-dimethylpropane-1,3-diamine (0.40 g, 1 mmol) and copper(II) acetate monohydrate (0.199 g, 1 mmol) were placed in the main arm of a branched tube. Ethanol was added to fill both arms. The tube was sealed and the main arm immersed in an oil bath at 333 K while the other was held at ambient temperature. After one week, crystals deposited in the cooler arm. These were filtered off and air dried. Yield: 75%. FT-IR data: ν(C═N) 1595 cm -1 .

Refinement
The H-atoms were placed in calculated positions (C-H 0.93 to 0.97 Å) and were included in the refinement in the riding model approximation, with U iso (H) set to 1.2 to 1.5U equiv (C  Fig. 1. The molecular structure of (I) showing the atom-labelling scheme and displacement ellipsoids at the 50% probability level.