Di-μ-iodo-bis{[1,1′-methyl­enebis(3,5-dimethyl-1H-pyrazole-κN²)]copper(I)}

In the title compound, [Cu₂I₂(C₁₁H₁₆N₄)₂], each of the two crystallographically equivalent Cu atoms is tetrahedrally coordinated by two N atoms from one 1,1′-methyl­ene­bis(3,5-di­methyl-1H-pyrazole) ligand and two bridging iodide anions. The mol­ecule has a crystallographic center of symmetry located at the mid-point of the Cu...Cu line. One H atom of the CH₂ group of the 1,1′-methyl­ene­bis(3,5-di­methyl-1H-pyrazole) ligand interacts with an iodide ion in an adjacent mol­ecule to afford pairwise intermolecular C—H...I contacts, thereby forming chains of mol­ecules running along the [101] direction.

S1. Comment

Cuprous halide (CuX) is known to easily form neutral adducts with various N-atom donor ligands (L). Some of these compounds show interesting catalytic properties (Mar Diaz-Requejo et al., 2003; Caballero et al., 2003) and rich luminescent properties (Lindsay et al., 1996; Vital et al., 2001; Rasika Dias et al., 2003). The most commonly encountered stoichiometry in CuX/L complexes is dimeric one, [CuXL]₂ (X = Cl, Br, I). For example, in the case of X = I, a nubmer of the dimeric complexes with different N-atom donor ligands (e.g. 1,10-phenanthroline, N,N-bis(pyrazol-1-ylmethyl)benzylamine, 2,6-bis(3-pyridyloxy)pyrazine and 2–2-ethylpyrazine) have been reported (Healy et al., 1985; Sheu et al., 1995; McMorran et al., 2002; Näther et al., 2003). Although the N-atom donor ligand bis(3,5-dimethylpyrazolyl)methane (dmpzm; Julia et al., 1982) has often been employed to react with transition metals to form interesting coordination compounds, for example [Hg(CN)₂(dmpzm)] (Cingolani et al., 1987), [NiCl₂(dmpzm)]₂ (Jansen et al., 1980) and [PdL'(dmpzm)]₂(ClO₄)₂·CH₃COCH₃·H₂O (L' is p-toluenethiolato; Sanchez et al., 2000), there is no report of the cuprous halide adduct of this ligand. We report here the crystal structure of the title cuprous iodide complex, (I), of dmpzm.

Complex (I) crystallizes in space group C2/c and the asymmetric unit contains one dmpzm ligand, one Cu atom and one iodide ion. The structure contains a dimetallocyclic Cu₂I₂ species with a crystallographic center of symmetry at the mid-point of the Cu···Cu line. Every Cu atom is coordinated by two N atoms of one dmpzm ligand and two bridging iodides, forming a distorted tetrahedral geometry with bond angles at the Cu atom ranging from 104.60 (10) to 117.89 (10)°. Each dmpzm ligand coordinates to one Cu center in an N,N'-bidentate fashion, forming a six-membered chelate ring. The dinuclear Cu₂I₂ core is asymmetric, as the Cu1—I1 and Cu1—I1ⁱ bond distances are 2.5719 (10) and 2.6933 (10) Å, while the Cu1—I1—Cu1ⁱ and I1—Cu1—I1ⁱ bond angles are 62.70 (3) and 117.30 (3)° [symmetry code (i): 1/2 − x, 1/2 − y, 1 − z]. The Cu—I bond lengths are comparable to the? mean value of 2.615 (1) Å in the similar [CuIL]₂ complex (L is 1,10-phenanthroline; Healy et al., 1985), but are shorter than that in [CuIL]₂ [2.7297 (9) Å; L is 2,6-bis(3-pyridyloxy)pyrazine; McMorran et al., 2002]. The Cu···Cu distance [2.7412 (13) Å] within the Cu₂I₂ core is shorter than that in [CuIL]₂ [2.803 (2) Å; L is 2,6-bis(3-pyridyloxy)pyrazine; McMorran et al., 2002], but longer than that in [CuIL]₂ [2.609 (2) Å; L is 1,10-phenanthroline; Healy et al., 1985].

The two Cu centres and the four N atoms (N1, N1ⁱ, N4 and N4ⁱ) lie close to the Cu₂N₄ plane (the maximum deviation from this plane is 0.18 Å). This plane is perpendicular to the Cu₂I₂ core. The Cu1—N1 and Cu1—N4 distances are almost identical, and the mean Cu—N bond length [2.097 (4) Å] is longer than that observed in [CuIL]₂ [2.0303 (18) Å; L is 2,6-bis(3-pyridyloxy)pyrazine; McMorran et al., 2002] and shorter than that in [CuIL]₂ [2.167 (9) Å; L is 2-(2'-pyridyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazolyl-1-oxyl; Oshio et al., 1996]. Each ligand in the title compound adopts an extended and twisted exo-anti conformation. Atom C6 of one of the methylene groups in the dinuclear complex lies 1.89 Å below the Cu₂N₄ plane, while the symmetry-related atom in the other ligand lies the same distance above the plane.

Atom H6B from the CH₂ group of each dmpzm ligand interacts with atom I1 in an adjacent molecule to afford pairwise intermolecular C—H···I contacts, thereby forming chains of molecules running along the [101] direction (Fig. 2 and Table 2).

S2. Experimental

An acetonitrile solution (10 ml) of bis(3,5-dimethylpyrazolyl)methane (0.020 g, 0.1 mmol) was added to CuI (0.035 g, 0.18 mmol). The mixture was stirred at room temperature for 1 h and then filtered. Slow evaporation of the filtrate gave rise to colorless prisms of (I). Yield 0.051 g (92%, based on Cu). The crystal used for the crystal structure determination was obtained directly from the above preparation. Analysis found: C 33.47, H 4.18, N, 14.19%; calculated for C₂₂H₃₂Co₂I₂N₈: C 33.22, H 4.38, N 13.75%. IR (KBr, cm⁻¹): 3008 (w), 2942 (w), 2920 (w), 1633 (m), 1558 (m), 1465 (m), 1427 (m), 1384 (s), 1287 (s), 1270 (m), 1035 (m), 792 (m), 676 (m).

S3. Refinement

The final difference Fourier map had a peak about 1.17 Å from atom C1. All H atoms were placed in idealized positions (C—H = 0.98 Å for methyl groups, 0.99 Å for methylene groups and 0.95 Å for phenyl groups) and constrained to ride on their parent atoms with U_iso(H) values of 1.2U_eq(C).

Computing details

Data collection: CrystalClear (Rigaku/MSC, 2001); cell refinement: CrystalClear; data reduction: CrystalStructure (Rigaku/MSC, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPII (Johnson, 1976); software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. A perspective view of (I), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level and H atoms are shown as small sheres of arbitrary radii. [Symmetry code: (i) 1/2 − x, 1/2 − y, 1 − z.]
	Fig. 2. A packing diagram of (I), viewed approximately down the b axis, showing chains of molecules linked by pairwise C—H···I interactions running along the [101] direction.

Di-µ-iodo-bis{[1,1'-methylenebis(3,5-dimethyl-4H-pyrazole)]copper(I)}

Crystal data

[Cu2I2(C11H16N4)2]	F(000) = 1536
Mr = 789.44	Dx = 1.884 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 5625 reflections
a = 17.924 (5) Å	θ = 3.1–27.5°
b = 11.702 (3) Å	µ = 3.77 mm^−1
c = 14.339 (4) Å	T = 193 K
β = 112.249 (6)°	Platelet, colorless
V = 2783.6 (13) Å^3	0.30 × 0.12 × 0.03 mm
Z = 4

Data collection

Rigaku Mercury CCD area-detector diffractometer	3187 independent reflections
Radiation source: fine-focus sealed tube	2742 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.041
ω scans	θmax = 27.5°, θmin = 3.1°
Absorption correction: multi-scan (Jacobson, 1998)	h = −23→23
Tmin = 0.397, Tmax = 0.895	k = −13→15
15314 measured reflections	l = −18→15

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)] = 0.042	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.082	H-atom parameters constrained
S = 1.11	w = 1/[σ^2(Fo^2) + (0.026P)^2 + 13.432P] where P = (Fo^2 + 2Fc^2)/3
3187 reflections	(Δ/σ)max < 0.001
155 parameters	Δρmax = 1.05 e Å^−3
0 restraints	Δρmin = −0.68 e Å^−3

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
I1	0.19514 (2)	0.36842 (3)	0.36810 (2)	0.0363 (1)
Cu1	0.32371 (3)	0.28540 (5)	0.50282 (4)	0.0327 (2)
N1	0.4086 (2)	0.4025 (3)	0.5930 (3)	0.0296 (11)
N2	0.4874 (2)	0.3684 (3)	0.6207 (3)	0.0297 (11)
N3	0.4869 (2)	0.2020 (3)	0.5232 (3)	0.0301 (11)
N4	0.4098 (2)	0.2118 (3)	0.4544 (3)	0.0305 (11)
C1	0.3369 (3)	0.5845 (4)	0.5754 (4)	0.0469 (17)
C2	0.4122 (3)	0.5167 (4)	0.5969 (3)	0.0334 (14)
C3	0.4917 (3)	0.5548 (4)	0.6251 (4)	0.0403 (17)
C4	0.5383 (3)	0.4588 (4)	0.6400 (3)	0.0336 (14)
C5	0.6272 (3)	0.4446 (5)	0.6732 (4)	0.0492 (19)
C6	0.5047 (2)	0.2477 (4)	0.6232 (3)	0.0309 (12)
C7	0.6225 (3)	0.1219 (5)	0.5443 (5)	0.0514 (19)
C8	0.5355 (3)	0.1465 (4)	0.4849 (4)	0.0382 (16)
C9	0.4880 (3)	0.1213 (4)	0.3876 (4)	0.0445 (17)
C10	0.4108 (3)	0.1627 (4)	0.3709 (4)	0.0369 (16)
C11	0.3364 (3)	0.1598 (5)	0.2778 (4)	0.0501 (17)
H1A	0.29840	0.53960	0.59390	0.0560*
H1B	0.34970	0.65530	0.61490	0.0560*
H1C	0.31310	0.60320	0.50350	0.0560*
H3	0.50970	0.63180	0.63250	0.0480*
H5A	0.63890	0.37380	0.64500	0.0590*
H5B	0.64960	0.50970	0.64960	0.0590*
H5C	0.65140	0.44110	0.74700	0.0590*
H6A	0.56230	0.23470	0.66490	0.0370*
H6B	0.47220	0.20650	0.65500	0.0370*
H7A	0.63130	0.11380	0.61570	0.0620*
H7B	0.63780	0.05080	0.52000	0.0620*
H7C	0.65550	0.18490	0.53610	0.0620*
H9	0.50430	0.08290	0.34010	0.0530*
H11A	0.30330	0.22700	0.27600	0.0610*
H11B	0.35110	0.16000	0.21860	0.0610*
H11C	0.30580	0.09030	0.27760	0.0610*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
I1	0.0257 (2)	0.0397 (2)	0.0370 (2)	−0.0038 (1)	0.0044 (1)	0.0131 (1)
Cu1	0.0226 (3)	0.0359 (3)	0.0355 (3)	−0.0025 (2)	0.0063 (2)	0.0027 (2)
N1	0.0235 (18)	0.0320 (19)	0.0307 (19)	−0.0036 (15)	0.0073 (15)	−0.0018 (16)
N2	0.0219 (17)	0.040 (2)	0.0249 (18)	−0.0080 (15)	0.0062 (14)	−0.0031 (16)
N3	0.0239 (18)	0.0328 (19)	0.032 (2)	0.0009 (15)	0.0087 (15)	0.0020 (16)
N4	0.0269 (18)	0.0308 (19)	0.032 (2)	−0.0014 (15)	0.0092 (15)	0.0006 (16)
C1	0.056 (3)	0.037 (3)	0.048 (3)	0.007 (2)	0.020 (3)	0.002 (2)
C2	0.039 (3)	0.034 (2)	0.025 (2)	−0.001 (2)	0.0097 (19)	−0.0003 (18)
C3	0.051 (3)	0.036 (3)	0.036 (3)	−0.018 (2)	0.019 (2)	−0.007 (2)
C4	0.030 (2)	0.048 (3)	0.023 (2)	−0.013 (2)	0.0102 (18)	−0.002 (2)
C5	0.037 (3)	0.069 (4)	0.044 (3)	−0.020 (3)	0.018 (2)	−0.010 (3)
C6	0.020 (2)	0.041 (2)	0.030 (2)	0.0015 (18)	0.0076 (17)	0.0041 (19)
C7	0.037 (3)	0.055 (3)	0.067 (4)	0.014 (2)	0.025 (3)	0.012 (3)
C8	0.036 (3)	0.032 (2)	0.050 (3)	0.006 (2)	0.020 (2)	0.005 (2)
C9	0.060 (3)	0.035 (3)	0.047 (3)	0.007 (2)	0.030 (3)	−0.001 (2)
C10	0.050 (3)	0.027 (2)	0.036 (3)	−0.003 (2)	0.019 (2)	−0.0029 (19)
C11	0.057 (3)	0.048 (3)	0.036 (3)	−0.003 (3)	0.007 (2)	−0.013 (2)

Geometric parameters (Å, º)

I1—Cu1	2.5719 (10)	C9—C10	1.399 (8)
I1—Cu1^i	2.6933 (10)	C10—C11	1.488 (8)
Cu1—N1	2.092 (4)	C1—H1A	0.9800
Cu1—N4	2.102 (4)	C1—H1B	0.9800
N1—N2	1.374 (6)	C1—H1C	0.9800
N1—C2	1.338 (6)	C3—H3	0.9500
N2—C4	1.355 (6)	C5—H5A	0.9800
N2—C6	1.444 (6)	C5—H5B	0.9800
N3—N4	1.365 (6)	C5—H5C	0.9800
N3—C6	1.448 (6)	C6—H6A	0.9900
N3—C8	1.358 (7)	C6—H6B	0.9900
N4—C10	1.334 (7)	C7—H7A	0.9800
C1—C2	1.494 (8)	C7—H7B	0.9800
C2—C3	1.399 (8)	C7—H7C	0.9800
C3—C4	1.368 (7)	C9—H9	0.9500
C4—C5	1.490 (8)	C11—H11A	0.9800
C7—C8	1.495 (8)	C11—H11B	0.9800
C8—C9	1.363 (8)	C11—H11C	0.9800
Cu1—I1—Cu1^i	62.69 (2)	C2—C1—H1A	109.00
I1—Cu1—N1	116.88 (10)	C2—C1—H1B	110.00
I1—Cu1—N4	117.89 (11)	C2—C1—H1C	110.00
I1—Cu1—I1^i	117.31 (2)	H1A—C1—H1B	109.00
N1—Cu1—N4	91.12 (15)	H1A—C1—H1C	109.00
I1^i—Cu1—N1	105.32 (11)	H1B—C1—H1C	109.00
I1^i—Cu1—N4	104.60 (10)	C2—C3—H3	127.00
Cu1—N1—N2	114.6 (3)	C4—C3—H3	127.00
Cu1—N1—C2	133.8 (3)	C4—C5—H5A	109.00
N2—N1—C2	104.5 (4)	C4—C5—H5B	109.00
N1—N2—C4	111.8 (4)	C4—C5—H5C	109.00
N1—N2—C6	118.6 (3)	H5A—C5—H5B	110.00
C4—N2—C6	129.6 (4)	H5A—C5—H5C	110.00
N4—N3—C6	117.9 (4)	H5B—C5—H5C	109.00
N4—N3—C8	112.1 (4)	N2—C6—H6A	109.00
C6—N3—C8	130.0 (4)	N2—C6—H6B	109.00
Cu1—N4—N3	117.7 (3)	N3—C6—H6A	109.00
Cu1—N4—C10	137.2 (4)	N3—C6—H6B	109.00
N3—N4—C10	105.0 (4)	H6A—C6—H6B	108.00
N1—C2—C1	119.8 (5)	C8—C7—H7A	110.00
N1—C2—C3	111.0 (4)	C8—C7—H7B	109.00
C1—C2—C3	129.2 (4)	C8—C7—H7C	109.00
C2—C3—C4	106.2 (4)	H7A—C7—H7B	109.00
N2—C4—C3	106.6 (5)	H7A—C7—H7C	109.00
N2—C4—C5	122.3 (4)	H7B—C7—H7C	109.00
C3—C4—C5	131.1 (5)	C8—C9—H9	126.00
N2—C6—N3	111.8 (3)	C10—C9—H9	126.00
N3—C8—C7	123.5 (5)	C10—C11—H11A	109.00
N3—C8—C9	105.6 (5)	C10—C11—H11B	109.00
C7—C8—C9	130.8 (5)	C10—C11—H11C	109.00
C8—C9—C10	107.1 (5)	H11A—C11—H11B	110.00
N4—C10—C9	110.1 (5)	H11A—C11—H11C	109.00
N4—C10—C11	120.2 (5)	H11B—C11—H11C	109.00
C9—C10—C11	129.7 (5)
Cu1^i—I1—Cu1—N1	−126.51 (13)	N1—N2—C4—C5	178.9 (4)
Cu1^i—I1—Cu1—N4	126.46 (12)	C6—N2—C4—C3	178.7 (4)
Cu1^i—I1—Cu1—I1^i	0.02 (8)	C6—N2—C4—C5	−2.7 (7)
Cu1—I1—Cu1^i—I1^i	−0.02 (10)	N1—N2—C6—N3	77.7 (5)
Cu1—I1—Cu1^i—N1^i	−131.98 (11)	C4—N2—C6—N3	−100.7 (5)
Cu1—I1—Cu1^i—N4^i	132.73 (11)	C6—N3—N4—Cu1	−2.8 (5)
I1—Cu1—N1—N2	−145.6 (3)	C6—N3—N4—C10	−179.6 (4)
I1—Cu1—N1—C2	−0.5 (5)	C8—N3—N4—Cu1	175.9 (3)
N4—Cu1—N1—N2	−23.3 (3)	C8—N3—N4—C10	−0.9 (5)
N4—Cu1—N1—C2	121.8 (5)	N4—N3—C6—N2	−58.9 (5)
I1^i—Cu1—N1—N2	82.1 (3)	C8—N3—C6—N2	122.6 (5)
I1^i—Cu1—N1—C2	−132.8 (4)	N4—N3—C8—C7	−178.8 (4)
I1—Cu1—N4—N3	159.1 (2)	N4—N3—C8—C9	0.9 (5)
I1—Cu1—N4—C10	−25.4 (5)	C6—N3—C8—C7	−0.3 (8)
N1—Cu1—N4—N3	37.6 (3)	C6—N3—C8—C9	179.4 (4)
N1—Cu1—N4—C10	−146.9 (5)	Cu1—N4—C10—C9	−175.3 (3)
I1^i—Cu1—N4—N3	−68.5 (3)	Cu1—N4—C10—C11	5.6 (7)
I1^i—Cu1—N4—C10	107.0 (5)	N3—N4—C10—C9	0.6 (5)
Cu1—N1—N2—C4	154.0 (3)	N3—N4—C10—C11	−178.6 (4)
Cu1—N1—N2—C6	−24.6 (5)	C1—C2—C3—C4	177.3 (4)
C2—N1—N2—C4	−0.8 (5)	N1—C2—C3—C4	−0.7 (5)
C2—N1—N2—C6	−179.4 (4)	C2—C3—C4—C5	−178.2 (5)
Cu1—N1—C2—C1	35.1 (7)	C2—C3—C4—N2	0.2 (5)
Cu1—N1—C2—C3	−146.6 (4)	N3—C8—C9—C10	−0.5 (5)
N2—N1—C2—C1	−177.4 (4)	C7—C8—C9—C10	179.2 (5)
N2—N1—C2—C3	0.9 (5)	C8—C9—C10—N4	−0.1 (6)
N1—N2—C4—C3	0.3 (5)	C8—C9—C10—C11	179.0 (5)

Symmetry code: (i) −x+1/2, −y+1/2, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C6—H6B···I1^i	0.99	3.02	3.877 (4)	145

Symmetry code: (i) −x+1/2, −y+1/2, −z+1.