Dichlorido(3,5,5′-trimethyl-1,3′-bi-1H-pyrazole-κ2 N 2,N 2′)copper(II)

Lhoussaine El Ghayati; Lahcen El Ammari; Mohamed Labd Taha; El Mostafa Tjiou

doi:10.1107/S1600536811004375

. 2011 Feb 12;67(Pt 3):m323–m324. doi: 10.1107/S1600536811004375

Dichlorido(3,5,5′-trimethyl-1,3′-bi-1H-pyrazole-κ² N ²,N ^2′)copper(II)

Lhoussaine El Ghayati ^a, Lahcen El Ammari ^b, Mohamed Labd Taha ^c, El Mostafa Tjiou ^a,^*

PMCID: PMC3051990 PMID: 21522255

Abstract

In the title complex, [CuCl₂(C₉H₁₂N₄)], the Cu^II atom exhibits a distorted square-planar coordination geometry involving two chloride ions and two N-atom donors from the bipyrazole ligand. The chelate ring including the Cu^II atom is essentially planar, with a maximum deviation of 0.0181 (17) Å for one of the coordinated N atoms. This plane forms a dihedral angle of 30.75 (6)° with the CuCl₂ plane. In the crystal, each pair of adjacent molecules is linked into a centrosymmetric dimer by N—H⋯Cl hydrogen bonds. The crystal structure is stabilized by intermolecular C—H⋯N and C—H⋯Cl hydrogen bonds and weak slipped π–π stacking interactions between symmetry-related molecules, with an interplanar separation of 3.439 (19) Å and a centroid–centroid distance of 3.581 (19) Å.

Related literature

For the preparation of biheterocyclic complexes, see: Juanes et al. (1985 ▶); Arrieta et al. (1998 ▶); El Ghayati et al. (2010 ▶); Cohen-Fernandez et al. (1979 ▶); Tarrago et al. (1980 ▶). For applications of transition metal complexes with biheterocyclic ligands, see: Bekhit & Abdel-Aziem (2004 ▶); Benabdallah et al. (2007 ▶); Das & Mittra (1978 ▶); Sendai et al. (2000 ▶); Attayibat et al. (2006 ▶).

Experimental

Crystal data

[CuCl₂(C₉H₁₂N₄)]
M _r = 310.67
Triclinic,
a = 8.5475 (2) Å
b = 9.3475 (3) Å
c = 9.3512 (3) Å
α = 66.379 (2)°
β = 62.876 (1)°
γ = 78.065 (2)°
V = 608.99 (3) Å³
Z = 2
Mo Kα radiation
μ = 2.21 mm⁻¹
T = 296 K
0.26 × 0.16 × 0.08 mm

Data collection

Bruker X8 APEXII area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.661, T _max = 0.838
19588 measured reflections
5535 independent reflections
4468 reflections with I > 2σ(I)
R _int = 0.020

Refinement

R[F ² > 2σ(F ²)] = 0.030
wR(F ²) = 0.096
S = 1.04
5535 reflections
145 parameters
H-atom parameters constrained
Δρ_max = 0.78 e Å⁻³
Δρ_min = −0.53 e Å⁻³

Data collection: APEX2 (Bruker, 2005 ▶); cell refinement: SAINT (Bruker, 2005 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia,1997 ▶) and PLATON (Spek, 2009 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811004375/fj2386sup1.cif

e-67-0m323-sup1.cif^{(15.9KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811004375/fj2386Isup2.hkl

e-67-0m323-Isup2.hkl^{(271KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N4—H4⋯Cl1ⁱ	0.86	2.38	3.1587 (12)	150
C7—H7B⋯N1ⁱⁱ	0.96	2.61	3.483 (2)	151
C9—H9B⋯Cl1ⁱⁱⁱ	0.96	2.79	3.5377 (19)	135

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) .

Acknowledgments

The authors thank the Unit of Support for Technical and Scientific Research (UATRS, CNRST) for the X-ray measurements.

supplementary crystallographic information

Comment

The 1,1'-bipyrazoles and 3,4'-bipyrazoles have been the subject of several studies (Juanes et al. (1985); Arrieta et al. (1998); El Ghayati et al. (2010). A particular interest has been brought to 1,3'-bipyrazoles which present, contrary to those cited above, a carbon– nitrogen bond between the two pyrazoles (Cohen-Fernandez et al. (1979); Tarrago et al. 1980).

The ability of biheterocycles to form biochemically interesting complexes, with transition metals has prompted several researchers to test them in some areas: medicine (Bekhit & Abdel-Aziem, (2004); Sendai et al. 2000), agriculture (Das & Mittra, 1978) corrosion (Benabdallah et al. 2007) and as extractors of metals such as Cu²⁺, Cd²⁺ and Pb²⁺ (Attayibat et al. 2006). To better understand the interactions between the bipyrazoles and transition metals we have chosen to study some copper complex of bipyrazole possessing a Carbone-nitrogen bond between the two pyrazolics cycles.

The title molecule is built up from two interconnected five-membered rings as schown in Fig.1. Each of the two heterocyclic rings and the linked carbon are almost planar with a maximum deviations of -0.0101 (15) Å and -0.0107 (15) Å from N1 and N3 respectively. The dihedral angle between them is about 3.80 (9)°. The Cu^II ion is surrounded by two nitrogen atoms belonging to the organic molecule and two chlorides which form a very distorted square planar.The values of adjacent angles around the Cu^II ions are in the range 78.14 (5)–98.297 (16)° and 151.99 (4)–161.72 (4)° (Table 1), which confirms the distorted square-planar geometry. The chelate ring (N1—N2—C4—N3) and the copper atom are almost planar with a maximum deviations of 0.0181 (17) Å from C4 and build dihedral angle of 30.75 (6)° with the plane through the three ions: Cu^II+ and two Cl^-.

In the crystal, each pair of molecules linked by N4—H4···Cl1 hydrogen bonds form a dimer as schown in Fig.2 and table 2. The structure is held together by weak slipped π-π stacking between symmetry related molecules (N3—N4—C4—C5—C6 rings) with interplanar distance of 3.439 (19) Å and centroid to centroid vector of 3.581 (19) Å (Fig. 2). The crystal structure is also stabilized by an intermolecular C7—H7B···N1 and C9—H9B···Cl1 hydrogen bonds as schown in Fig.2 and Table 2.

Experimental

The title compound was synthesized by mixing a solution of bipyrazole in methanol and an aqueous solution of cupric chloride with ligand/metal ratio of 2. Heating was maintaind for few minutes.Then a pinch of NaCl was added and heating was continued until the solution became clear. After a long time, green crystals were collected and dried over P2O5.