Di-μ-chlorido-dichloridobis{8-[2-(dimethylamino)ethylamino]quinoline}dicadmium monohydrate

The title complex, [Cd2Cl4(C13H17N3)2]·H2O, is centrosymmetic and contains two Cd2+ ions bridged by two Cl− ions, leading to a strictly planar Cd2Cl2 core. Each Cd2+ ion is further coordinated by an additional Cl− ion and three N atoms of a tridentate 8-[2-(dimethylamino)ethylamino]quinoline ligand in the form of a considerably distorted octahedron for the overall coordination sphere. A lattice water molecule is located on a twofold rotation axis and links pairs of complexes through N—H⋯O and O—H⋯Cl hydrogen bonds.

The title complex, [Cd 2 Cl 4 (C 13 H 17 N 3 ) 2 ]ÁH 2 O, is centrosymmetic and contains two Cd 2+ ions bridged by two Cl À ions, leading to a strictly planar Cd 2 Cl 2 core. Each Cd 2+ ion is further coordinated by an additional Cl À ion and three N atoms of a tridentate 8-[2-(dimethylamino)ethylamino]quinoline ligand in the form of a considerably distorted octahedron for the overall coordination sphere. A lattice water molecule is located on a twofold rotation axis and links pairs of complexes through N-HÁ Á ÁO and O-HÁ Á ÁCl hydrogen bonds.   Table 1 Hydrogen-bond geometry (Å , ).
Some quinoline-containing ligands show interesting biological activities (Puviarasan et al., 2004), such as antiphlogistic activity in rats, bacterial inhibitors, are precursors to a number of antimalarial and cancer drugs, or act as local anaesthetics. In addition, they are also active against staphylococcus, epidermis, neisseria and gonorrhea. Derivatives of aminoquinoline are used as inhibitors of the human immunedefciency virus (HIV). Although the biologically active ligand 8-[2-(diethylamino)ethylamino]quinoline was synthesized some time ago (Hartshorn & Baird, 1946), to the best of our knowledge, the methyl analogue has not been reported up to date. In addition, complexation properties of such tridentate asymmetric ligands have been neglected. Inspired by the multifarious properties shown by quinoline-containing ligands, the methyl analogue of the tridentate ligand 8-[2-(diethylamino)ethylamino]quinoline, has been synthesized and some aspects of its coordination chemistry are currently being investigated. One of the results is reported here, viz. Complex (I) is centrosymmetic and hence the asymmetric unit contains one half of the molecule (Fig. 1). The two Cd 2+ ions are bridged by two Clions. In addition to the bridging ions, each Cd 2+ is also coordinated by another Clion and three N atoms from the tridentate ligand in the form of a considerably distorted octahedron. Large deviations from right angles are observed, with angles ranging from 69.48 (5)° to 101.08 (4)°. The crystal structure ( Fig. 2) also contains a water molecule located on a twofold rotation axis. The water molecule is both an acceptor and a donor to hydrogen bonding, accepting two N-H···O bonds and donating two O-H···Cl bonds to a pairs of the complex units ( Fig. 3, Table   1).

Experimental
The ligand was prepared by the standard Bucherer procedure (Amoroso et al., 2009;Hartshorn & Baird, 1946). To a stirred dry methanolic solution (30 ml) of cadmium dichloride (0.2 g; 0.0011 mol) kept under a positive nitrogen pressure, a dry methanolic solution (10 ml) of the ligand (0.24 g; 0.0011 mol) was slowly added. The resulting solution was stirred at room temperature for 3 h. The solvent was then removed under vacuum and the sticky solid obtained was

Refinement
Ligand H atoms were positioned geometrically and refined using a riding model with U iso (H) constrained to be 1.2 times U eq for the atom it is bonded to (except for methyl groups where it was 1.5 times with free rotation about the C-C bond).
The water hydrogen was refined freely. Of the low angle reflections missing from the refinement, reflections (110), (200), (202) and (111) were omitted due to deviant intensities consistent with obstruction by the beamstop; the rest of the missing reflections were eliminated automatically during data processing, possibly as overloads.  The molecular structure of the centrosymmetric complex (I), showing atom labels and atoms with their displacement ellipsoids at the 50% probability level for non-H atoms. Non-labelled atoms are generated by symmetry code -x, -y, -z.     Special details Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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.