cis-(Nitrato-κ2 O,O′)(2,5,5,7,9,12,12,14-octamethyl-1,4,8,11-tetraazacyclotetradecane-κ4 N,N′,N′′,N′′′)cadmium nitrate hemihydrate

The CdII atom in the title complex, [Cd(NO3)(C18H40N4)]NO3·0.5H2O, is coordinated within a cis-N4O2 donor set provided by the tetradentate macrocyclic ligand and two O atoms of a nitrate anion; the coordination geometry is distorted octahedral. The lattice water molecule is located on a twofold rotation axis. N—H⋯O hydrogen bonds and weak C—H⋯O interactions link the complex cations into a supramolecular layer in the bc plane. Layers are connected by O—H⋯O hydrogen bonds between the lattice water molecule and the non-coordinating nitrate anion, as well as by weak C—H⋯O contacts.

The Cd II atom in the title complex, [Cd(NO 3 )(C 18 H 40 N 4 )]-NO 3 Á0.5H 2 O, is coordinated within a cis-N 4 O 2 donor set provided by the tetradentate macrocyclic ligand and two O atoms of a nitrate anion; the coordination geometry is distorted octahedral. The lattice water molecule is located on a twofold rotation axis. N-HÁ Á ÁO hydrogen bonds and weak C-HÁ Á ÁO interactions link the complex cations into a supramolecular layer in the bc plane. Layers are connected by O-HÁ Á ÁO hydrogen bonds between the lattice water molecule and the non-coordinating nitrate anion, as well as by weak C-HÁ Á ÁO contacts.

Related literature
For background to macrocyclic complexes, see: Hazari et al. (2008). For the crystal structure of the anhydrous form of the title complex, see: Hazari et al. (2010). For the synthesis of the macrocyclic ligand, see: Bembi et al. (1989).
In cation in (I), Fig. 1, the Cd II atom exists within a cis-N 4 O 2 donor set defined by the four nitrogen atoms of the macrocyclic ligand and two nitrate-O atoms, Table 1. The coordination geometry is based on an octahedron, but with significant distortions owing in part to the restricted bite angle of the nitrate ligand as manifested in the O1-Cd-O2 angle of 52.80 (7)°. A more regular geometry was found in the anhydrous form of the complex (Hazari et al., 2010). The  Table 2.

Experimental
The macrocyclic ligand, 3,10-C-meso-2,5,5,7,9,12,12,14-octamethyl-1,4,8,11-tetraazacyclotetradecane (0.312 g, 1.0 mmol), prepared in accord with the literature procedure (Bembi et al., 1989), was dissolved in methanol (20 ml) in a round bottomed flask. Cadmium(II) nitrate hexahydrate (0.344 g, 1.0 mmol) in methanol (20 ml) was added drop wise to the round bottom flask with continuous stirring The mixture was heated for about 30 min. on a steam bath to ensure the completion of the reaction and was then filtered. After 48 h, the white crystalline product that formed from the filtrate was filtered off, washed with methanol followed by diethylether and dried in a desiccator over silica gel. Yield 85%.

Special details
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.