Bis(μ-cyclohexane-1,4-dicarboxylato)bis{aqua[1-(1H-imidazo[4,5-f][1,10]phenanthrolin-2-yl)naphthalen-2-ol]cadmium} monohydrate

The asymmetric unit of the title compound, [Cd2(C8H10O4)2(C23H14N4O)2(H2O)2]·H2O, consists of one half of the dimeric complex, which lies about an inversion centre, and a half-occupancy solvent water molecule on a general position. Each CdII cation is six-coordinated by the two N atoms from one 1-(1H-imidazo[4,5-f][1,10]phenanthrolin-2-yl)naphthalen-2-ol (L) ligand and three O atoms from two different 1,4-chdc2− ligands (1,4-H2chdc = cyclohexane-1,4-dicarboxylic acid), two coordinating in a bidentate fashion and the other in a monodentate fashion. The distorted octahedral coordination sphere is completed by a coordinated water molecule. The CdII atoms are each bridged by two 1,4-chdc2− ligands, forming an inversion dimer with the L ligands located on the outside of the dimeric unit. An intramolecular N—H⋯O hydrogen bond occurs. In the crystal, O—H⋯O and N—H⋯O hydrogen-bonding interactions stabilize the packing.


Related literature
For background to the coordination chemistry of 1,10phenanthroline and its derivatives, see: Wang et al. (2010).

Experimental
A mixture of CdCl 2 . 2.5H 2 O (0.5 mmol), 1,4-H 2 chdc (0.5 mmol) and L (0.5 mmol) in 10 mL distilled water was heated at 460 K in a Teflon-lined stainless steel autoclave for seven days. The reaction system was then slowly cooled to room temperature. Pale yellow crystals of (I) suitable for single crystal X-ray diffraction analysis were collected from the final reaction system by filtration, washed several times with distilled water and dried in air at ambient temperature. Yield: 29% based on Cd(II).

Refinement
All H atoms on C and N atoms were positioned geometrically (N-H = 0.86 Å and C-H = 0.93 Å) and refined as riding, with U iso (H)=1.2U eq (carrier). The water H-atoms of O1W were located in difference Fourier maps, and were refined freely.
However, the hydrogen atoms of the half occupancy water molecule were not located in difference Fourier maps. Fig. 1

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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.
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )