Di-μ-hydroxido-κ⁴O:O-di-μ-perchlorato-κ⁴O:O′-bis­­[(2,2′-bi­pyridine-κ²N,N′)copper(II)]

In the title binuclear copper(II) complex, [Cu₂(ClO₄)₂(OH)₂(C₁₀H₈N₂)₂], the Cu^II ion is coordinated in the form of a Jahn–Teller distorted octahedron by two bi­pyridine N atoms, two perchlorate O atoms and two hydroxide O atoms, and displays a distorted octa­hedral geometry. The mol­ecule belongs to the symmetry point group C_2h. The Cu^II ion is located on a twofold rotation axis and the hydroxide and perchlorate ligands are located on a mirror plane. Within the dinuclear mol­ecule, the Cu⋯Cu separation is 2.8614 (7) Å. The crystal structure exhibits O—H⋯O, C—H⋯O and π–π [centroid–centroid distance = 3.5374 (13) Å] inter­actions.

Related literature

For the biological activity of copper complexes, see: Müller et al. (2003); Lo et al. (2000). For related strucutures, see: Li et al. (2009); Shaikh et al. (2012); Wang et al. (2010).

Experimental

Crystal data

• [Cu₂(ClO₄)₂(OH)₂(C₁₀H₈N₂)₂]

• M_r = 672.36

• Monoclinic, C 2/m

• a = 13.6014 (12) Å

• b = 15.2064 (13) Å

• c = 6.2738 (6) Å

• β = 113.587 (3)°

• V = 1189.19 (19) ų

• Z = 2

• Mo Kα radiation

• μ = 2.08 mm⁻¹

• T = 295 K

• 0.24 × 0.20 × 0.18 mm

Data collection

• Bruker Kappa APEXII diffractometer

• Absorption correction: multi-scan (SADABS; Sheldrick, 1996) T_min = 0.635, T_max = 0.706

• 4520 measured reflections

• 1516 independent reflections

• 1330 reflections with I > 2σ(I)

• R_int = 0.022

Refinement

• R[F² > 2σ(F²)] = 0.026

• wR(F²) = 0.077

• S = 1.03

• 1516 reflections

• 95 parameters

• 1 restraint

• H atoms treated by a mixture of independent and constrained refinement

• Δρ_max = 0.44 e Å⁻³

• Δρ_min = −0.31 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1⋯O2^i	0.81 (2)	2.34 (1)	3.134 (3)	169 (4)
C5—H5⋯O2^i	0.93	2.52	3.381 (3)	153
Symmetry code: (i) x, y, z+1.

Data collection: APEX2 (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: SHELXL97.

Supporting information

S1. Comment

Copper complexes have received much attention because of their interesting interactions with biological ligands to generate stable mixed coordinated complexes, which play a key role in life processes such as enzymatic catalysis, storage and conveyance of the matter, transfer of copper ions (Müller et al., 2003; Lo et al., 2000). In the molecular structure of the title compound (Fig. 1), the bond distances Cu1—N1 = 1.9865 (16) Å and Cu1—O1 = 1.9097 (13) Å agree with the reported similar structures (Shaikh et al., 2012; Wang et al., 2010). Each Cu^(II) cation is hexa-coordinated with two N atoms of bipyridine, two hydroxyl group O atoms bridging the copper cations and two O atoms of perchlorate anions, showing distorted octahedral environment (Fig. 1). The molecule belongs to the symmetry point group C_2h. The two copper anions are separated by a distance of 2.8614 (7) Å, indicating a strong Cu^II···Cu^II interaction which is comparable with the Cu^II···Cu^II distance in the reported structure (Li et al., 2009).

The crystal structure is stabilized by O—H···O, C—H···O (Fig. 2 & Table 1) and π–π [Cg1···Cg1ⁱ distance = 3.5374 (13) Å; (i) -2-x, y, -z; Cg1 is the centroid of the ring (N1/C1/-C5)] interactions.

Related literature

For the biological activity of copper complexes, see: Müller et al. (2003); Lo et al. (2000). For related strucutures, see: Li et al. (2009); Shaikh et al. (2012); Wang et al. (2010).

S2. Experimental

To a solution of 2,2'-bipyridine (0.25 g, 1.60 mM) in 10 mL methanol, Cu(ClO₄)₂. 6H₂O (0.59 g, 1.60 mM) in 10 mL of methanol, was slowly added dropwise with constant stirring. The mixture was stirred well at room temperature for about 3 h, the formed blue solution was then concentrated to one third of its volume, washed well (with water, methanol and ether) and dried under vacuum. The complex was then recrystallized in ethanol by the slow evaporation method to obtain X-ray quality single crystals of the complex, which appeared gradually after several days.

S3. Refinement

The H atom of the hydroxyl O atom was located in a difference Fourier map and refined with the O1—H1 distance restrained to 0.82 (1)Å. All other H atoms were positioned geometrically and refined using riding model, with C—H = 0.93 Å and U_iso(H) = 1.2U_eq(C).

One reflection (1 1 0) was omitted from the final cycles of refinement owing to poor agreement.

Computing details

Data collection: APEX2 (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT (Bruker, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures

	Fig. 1. The molecular structure of the title compound, with atom labels and 30% probability displacement ellipsoids for non-H atoms. Symmetry codes : (a) -2-x, y, -1-z; (b) -2-x, -y, -1-z; (c) x, -y, z.
	Fig. 2. The packing of the title compound, viewed down a axis. Hydrogen bonds are shown as dashed lines. H atoms not involved in hydrogen bonding have been omitted.

Di-µ-hydroxido-κ⁴O:O-di-µ-perchlorato-κ⁴O:O'-bis[(2,2'-bipyridine-κ²N,N')copper(II)]

Crystal data

[Cu2(ClO4)2(OH)2(C10H8N2)2]	F(000) = 676
Mr = 672.36	Dx = 1.878 Mg m^−3
Monoclinic, C2/m	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2y	Cell parameters from 4012 reflections
a = 13.6014 (12) Å	θ = 3.2–28.3°
b = 15.2064 (13) Å	µ = 2.08 mm^−1
c = 6.2738 (6) Å	T = 295 K
β = 113.587 (3)°	Block, colourless
V = 1189.19 (19) Å^3	0.24 × 0.20 × 0.18 mm
Z = 2

Data collection

Bruker Kappa APEXII diffractometer	1516 independent reflections
Radiation source: fine-focus sealed tube	1330 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.022
ω and ϕ scans	θmax = 28.3°, θmin = 3.3°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −17→17
Tmin = 0.635, Tmax = 0.706	k = −20→18
4520 measured reflections	l = −8→8

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.026	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.077	H atoms treated by a mixture of independent and constrained refinement
S = 1.03	w = 1/[σ^2(Fo^2) + (0.0419P)^2 + 0.8702P] where P = (Fo^2 + 2Fc^2)/3
1516 reflections	(Δ/σ)max < 0.001
95 parameters	Δρmax = 0.44 e Å^−3
1 restraint	Δρmin = −0.31 e Å^−3

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 F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > 2sigma(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² 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 (Ų)

	x	y	z	Uiso*/Ueq
C1	−0.96779 (13)	−0.27374 (12)	−0.3726 (3)	0.0316 (4)
C2	−0.93192 (16)	−0.34870 (14)	−0.2418 (3)	0.0415 (4)
H2	−0.9468	−0.4039	−0.3115	0.050*
C3	−0.87311 (17)	−0.34058 (17)	−0.0041 (4)	0.0481 (5)
H3	−0.8474	−0.3903	0.0877	0.058*
C4	−0.85328 (16)	−0.25859 (17)	0.0941 (4)	0.0469 (5)
H4	−0.8151	−0.2520	0.2536	0.056*
C5	−0.89063 (16)	−0.18601 (16)	−0.0462 (3)	0.0429 (5)
H5	−0.8767	−0.1303	0.0207	0.052*
N1	−0.94650 (12)	−0.19315 (11)	−0.2767 (2)	0.0331 (3)
O1	−0.95484 (16)	0.0000	−0.2803 (3)	0.0416 (5)
O2	−0.75740 (19)	0.0000	−0.7997 (4)	0.0547 (6)
O3	−0.79963 (14)	−0.07747 (11)	−0.5234 (3)	0.0566 (4)
O4	−0.63781 (17)	0.0000	−0.4095 (4)	0.0584 (6)
Cl1	−0.74892 (5)	0.0000	−0.56343 (11)	0.03846 (17)
Cu1	−1.0000	−0.09408 (2)	−0.5000	0.03551 (13)
H1	−0.8987 (16)	0.0000	−0.167 (4)	0.053*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0339 (8)	0.0310 (9)	0.0312 (9)	−0.0004 (7)	0.0143 (7)	0.0011 (7)
C2	0.0480 (11)	0.0352 (10)	0.0402 (10)	0.0028 (8)	0.0163 (9)	0.0054 (8)
C3	0.0491 (11)	0.0519 (14)	0.0398 (11)	0.0063 (10)	0.0139 (9)	0.0167 (10)
C4	0.0411 (10)	0.0649 (15)	0.0299 (9)	−0.0013 (10)	0.0093 (8)	0.0043 (10)
C5	0.0442 (10)	0.0481 (12)	0.0330 (9)	−0.0068 (9)	0.0118 (8)	−0.0047 (9)
N1	0.0373 (7)	0.0311 (8)	0.0297 (7)	−0.0038 (6)	0.0122 (6)	−0.0013 (6)
O1	0.0478 (11)	0.0305 (10)	0.0335 (10)	0.000	0.0027 (8)	0.000
O2	0.0678 (14)	0.0552 (14)	0.0335 (11)	0.000	0.0123 (10)	0.000
O3	0.0610 (10)	0.0435 (9)	0.0628 (11)	−0.0040 (7)	0.0223 (8)	0.0070 (8)
O4	0.0420 (11)	0.0687 (16)	0.0470 (13)	0.000	−0.0004 (10)	0.000
Cl1	0.0394 (3)	0.0367 (3)	0.0315 (3)	0.000	0.0061 (3)	0.000
Cu1	0.0431 (2)	0.02606 (18)	0.0349 (2)	0.000	0.01302 (14)	0.000

Geometric parameters (Å, º)

C1—N1	1.345 (2)	N1—Cu1	1.9865 (16)
C1—C2	1.375 (3)	O1—Cu1	1.9097 (13)
C1—C1^i	1.484 (3)	O1—Cu1^ii	1.9097 (13)
C2—C3	1.388 (3)	O1—H1	0.807 (10)
C2—H2	0.9300	O2—Cl1	1.440 (2)
C3—C4	1.369 (4)	O3—Cl1	1.4372 (17)
C3—H3	0.9300	O4—Cl1	1.431 (2)
C4—C5	1.376 (3)	Cl1—O3^iii	1.4372 (17)
C4—H4	0.9300	Cu1—O1^ii	1.9097 (13)
C5—N1	1.342 (2)	Cu1—N1^i	1.9865 (16)
C5—H5	0.9300	Cu1—Cu1^ii	2.8614 (7)
N1—C1—C2	121.81 (16)	Cu1—O1—H1	123.4 (12)
N1—C1—C1^i	114.25 (10)	Cu1^ii—O1—H1	123.4 (12)
C2—C1—C1^i	123.94 (11)	O4—Cl1—O3	109.45 (9)
C1—C2—C3	118.8 (2)	O4—Cl1—O3^iii	109.45 (9)
C1—C2—H2	120.6	O3—Cl1—O3^iii	110.11 (15)
C3—C2—H2	120.6	O4—Cl1—O2	108.83 (15)
C4—C3—C2	119.3 (2)	O3—Cl1—O2	109.49 (9)
C4—C3—H3	120.3	O3^iii—Cl1—O2	109.49 (9)
C2—C3—H3	120.3	O1—Cu1—O1^ii	82.97 (9)
C3—C4—C5	119.13 (19)	O1—Cu1—N1^i	176.89 (8)
C3—C4—H4	120.4	O1^ii—Cu1—N1^i	97.91 (6)
C5—C4—H4	120.4	O1—Cu1—N1	97.91 (6)
N1—C5—C4	122.0 (2)	O1^ii—Cu1—N1	176.89 (7)
N1—C5—H5	119.0	N1^i—Cu1—N1	81.37 (9)
C4—C5—H5	119.0	O1—Cu1—Cu1^ii	41.48 (4)
C5—N1—C1	118.93 (17)	O1^ii—Cu1—Cu1^ii	41.48 (4)
C5—N1—Cu1	126.04 (15)	N1^i—Cu1—Cu1^ii	139.32 (4)
C1—N1—Cu1	115.01 (11)	N1—Cu1—Cu1^ii	139.32 (4)
Cu1—O1—Cu1^ii	97.03 (9)
N1—C1—C2—C3	0.7 (3)	C1^i—C1—N1—Cu1	−2.8 (2)
C1^i—C1—C2—C3	−179.4 (2)	Cu1^ii—O1—Cu1—O1^ii	0.0
C1—C2—C3—C4	0.6 (3)	Cu1^ii—O1—Cu1—N1	176.99 (7)
C2—C3—C4—C5	−1.1 (3)	C5—N1—Cu1—O1	−3.53 (17)
C3—C4—C5—N1	0.4 (3)	C1—N1—Cu1—O1	178.01 (13)
C4—C5—N1—C1	0.9 (3)	C5—N1—Cu1—N1^i	179.53 (19)
C4—C5—N1—Cu1	−177.48 (15)	C1—N1—Cu1—N1^i	1.07 (9)
C2—C1—N1—C5	−1.4 (3)	C5—N1—Cu1—Cu1^ii	−0.47 (19)
C1^i—C1—N1—C5	178.60 (18)	C1—N1—Cu1—Cu1^ii	−178.93 (9)
C2—C1—N1—Cu1	177.14 (14)

Symmetry codes: (i) −x−2, y, −z−1; (ii) −x−2, −y, −z−1; (iii) x, −y, z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···O2^iv	0.81 (2)	2.34 (1)	3.134 (3)	169 (4)
C5—H5···O2^iv	0.93	2.52	3.381 (3)	153

Symmetry code: (iv) x, y, z+1.