(Ethylenediamine-κ2 N,N′)bis(perchlorato-κO)bis(pyridine-κN)copper(II)

In the title compound, [Cu(ClO4)2(C2H8N2)(C5H5N)2], the CuII cation is located on a twofold rotation axis and is coordinated by four N and two O atoms in a tetragonally distorted octahedral geometry. The crystal packing can be described as ClO4 tetrahedra and CuN4O2 octahedra alternating in a zigzag fashion along the c axis. The structure is stabilized by intermolecular N—H⋯O and C—H⋯O hydrogen bonds, as well as π–π interactions [centroid–centroid distance = 3.7179 (15) Å].

In the title compound, [Cu(ClO 4 ) 2 (C 2 H 8 N 2 )(C 5 H 5 N) 2 ], the Cu II cation is located on a twofold rotation axis and is coordinated by four N and two O atoms in a tetragonally distorted octahedral geometry. The crystal packing can be described as ClO 4 tetrahedra and CuN 4 O 2 octahedra alternating in a zigzag fashion along the c axis. The structure is stabilized by intermolecular N-HÁ Á ÁO and C-HÁ Á ÁO hydrogen bonds, as well asinteractions [centroidcentroid distance = 3.7179 (15) Å ].

Comment
Aliphatic and aromatic amines such as ethylenediamine and pyridine are commonly known as the good chelating properties towards transition metals (De Stefano et al., 1999). In this case, the title compound was obtained when mixing ethylenediamine, 2-hydroxy-6-[3-(1H-pyrrol-1-yl)propoxy]acetophenone and perchlorate of copper in a methanolic solution. This work have been focused the synthesis of half-units for the preparation of non-symmetrical Schiff base ligands (Costes et al., 1998) but, the resulting compound was not the expected material. Thus, it seems that the preferential formation of unexpected copper complex is probably due to the no heating of the mixture at the first moments after mixing the different reagents or to the higher affinity the copper ion towards the amines previously indicated (Moncol et al., 2008). This is in accordance with high donor effect of these both amines as reported in the literature for the synthesis of coordination compounds using aliphatic (Sing et al., 2004)) and aromatic amines such as bipyridinc ligands (Elliot & Herchenhart, 1982). We report here the synthesis of title compound and its crystal structure.
The molecular geometry of structure, (I), and the atomic numbering used, is illustrated in Fig. 1. The Cu II ion is coordinated in an irregular octahedral geometry by four N atoms via two pyridine and one ethylenediamine moiety and two O atoms via two perchlorate. The bond lengths for coordination Cu II sphere is ranging from 2.017 (2) to 2.0206 (19) Å for Cu-N distances and is 2.613 (3) Å for Cu-O distance ( Table 1). The crystal packing in the title structure can be described by alterning ClO 4 tetrahedra and CuN 4 O 2 octahedra of complex in zigzag along the c axis (Fig. 2). It's stabilized by intermolecular N-H···O hydrogen bonding (Table 2) and π-π interactions.
Experimental 259 mg (1 mmol) of 2-hydroxy-6-[3-(1H-pyrrol-1-yl)propoxy]acetophenone, 373 mg (1 mmol) of copper perchlorate hexahydrated and an excess of pyridine were dissolved in 12 ml of methanol. This solution was placed in a three necked flask surmounted by a condenser before to add it dropwisely a methanolic solution (8 ml) containing 60 mg (1 mmol) of ethylenediamine. This mixture was kept under nitrogen atmosphere and stirring for about 2 h to observe an abundant mallow precipitate. This solid was recovered by filtration, copiously washed with methanol and the suitable crystals were obtained by slow evaporation from the filtrate.

Refinement
The remaining H atoms were localized on Fourier maps but introduced in calculated positions and treated as riding on their parent atoms (C and N) with C-H = 0.97 Å (methylene) or 0.93 Å (aromatic) and N-H = 0.90 Å with U iso (H) = 1.2U eq (C or N).  (Farrugia, 1997) and DIAMOND (Brandenburg & Berndt, 2001); software used to prepare material for publication:

Figure 1
Drawing the molecular geometry of (I) with the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are represented as small spheres of arbitrary radii.  Alternating polyhedra of (I) viewed via a axis showing ClO 4 tetrahedra in green and CuN 4 O 2 octahedra in yellow.

(Ethylenediamine-κ 2 N,N′)bis(perchlorato-κO)bis(pyridine-κN)copper(II)
Crystal data 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.