Di-μ-iodo-bis­[(4,4′-dimethyl-2,2′-bipyridine)copper(I)]

The title binuclear compound, [Cu₂I₂(C₁₂H₁₂N₂)₂], has crystallographic mirror symmetry. The Cu atoms are monovalent and have a tetra­hedral environment. The mol­ecules pack in a layer structure.

Key indicators

• Single-crystal X-ray study
• T = 295 K
• Mean [sigma](C-C) = 0.008 Å
• R factor = 0.050
• wR factor = 0.129
• Data-to-parameter ratio = 21.2

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT232_ALERT_2_B Hirshfeld Test Diff (M-X)  I1     -   Cu1     ..      11.41 su
PLAT232_ALERT_2_B Hirshfeld Test Diff (M-X)  I2     -   Cu1     ..      13.31 su

Alert level C
ABSTM02_ALERT_3_C  The ratio of expected to reported Tmax/Tmin(RR') is < 0.90
            Tmin and Tmax reported:      0.403     0.557
            Tmin(prime) and Tmax expected:      0.485     0.557
            RR(prime) =      0.830
            Please check that your absorption correction is appropriate.
PLAT061_ALERT_3_C Tmax/Tmin Range Test RR' too Large .............       0.81
PLAT601_ALERT_2_C Structure Contains Solvent Accessible VOIDS of .      46.00 A   3 

   0 ALERT level A = In general: serious problem
   2 ALERT level B = Potentially serious problem
   3 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   3 ALERT type 2 Indicator that the structure model may be wrong or deficient
   2 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

4,4'-Dimethyl-2,2'-bipyridine, a commercially available bidentate chelating heterocyclic ligand, furnishes complexes from a large range of metal salts. The structure of the binuclear title compound, (I), obtained from copper(I) iodide is shown in Fig. 1. Each Cu atom is chelated by the heterocycle and two µ₂-I atoms in a four-coordinate environment and shows tetrahedron geometry (Fig. 1). The two Cu—I bond lengths [2.5948 (9) and 2.6307 (9) Å] are comparable with those reported earlier (Kutoglu et al., 1991). The molecule has crystallographic mirror

symmetry and the structure is a binuclear layer compound. The two copper(I) atoms are separated by a distance of 2.5274 (14) Å indicating a strong Cu^I···Cu^I interaction, which is comparable with the Cu^I···Cu^I distance found previously (Che et al., 2000; Hou et al., 2004).

Related literature

For related literature, see Che et al. (2000); Hou et al. (2004); Kutoglu et al. (1991).

S2. Experimental

4,4'-dimethyl-2,2'-bipyridine was commercially available and was used as received without further purification. This compound (0.0184 g, 0.1 mmol), together with a saturated potassium iodide solution containing copper(I) iodide (0.0190 g, 0.1 mmol), were dissolved in water (10 ml). Then the solution was placed and sealed in a 15 ml Teflon-lined stainless steel reactor and heated to 453 K for 72 h, then cooled down to room temperature at a rate of 5 K/h. Red block crystals were formed in about 50% yield.

S3. Refinement

H atoms were placed in calculated positions (C—H 0.93 Å; U_iso(H) = 1.2U_eq(C) for the ring H atoms and C—H 0.96 Å; U_iso(H) = 1.5U_eq(C) for the methyl groups) and were included in the refinement in the riding model approximation. The largest peak in the final difference map was 0.95 Å from atom I2.

Computing details

Data collection: SMART (Bruker, 2002); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97.

Figures

Fig. 1. A view of the molecule of (I) showing the atom labeling scheme. Displacement ellipsoids are drawn at the 50% probability level, and H atoms are drawn as spheres of arbitrary radii. Atoms labeled with "a" are generated by the symmetry operation x, 1/2 - y, z.

Di-µ-iodo-bis[(4,4'-dimethyl-2,2'-bipyridine)copper(I)]

Crystal data

[Cu2I2(C12H12N2)2]	F(000) = 1440
Mr = 749.35	Dx = 1.854 Mg m^−3
Orthorhombic, Pnma	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2n	Cell parameters from 2945 reflections
a = 11.162 (2) Å	θ = 2.2–24.9°
b = 17.432 (4) Å	µ = 3.90 mm^−1
c = 13.794 (3) Å	T = 295 K
V = 2684.0 (10) Å^3	Block, red
Z = 4	0.18 × 0.16 × 0.15 mm

Data collection

Bruker APEX area-detector diffractometer	3178 independent reflections
Radiation source: fine-focus sealed tube	2373 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.031
φ and ω scans	θmax = 27.5°, θmin = 1.9°
Absorption correction: multi-scan (SADABS; Bruker, 2002)	h = −14→14
Tmin = 0.403, Tmax = 0.557	k = −21→22
15856 measured reflections	l = −8→17

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)] = 0.050	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.129	H-atom parameters constrained
S = 1.10	w = 1/[σ^2(Fo^2) + (0.0571P)^2 + 3.2733P] where P = (Fo^2 + 2Fc^2)/3
3178 reflections	(Δ/σ)max = 0.001
150 parameters	Δρmax = 1.53 e Å^−3
0 restraints	Δρmin = −0.78 e Å^−3

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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 > σ(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
Cu1	0.00472 (7)	0.32249 (4)	0.35891 (5)	0.0652 (2)
I1	0.02234 (5)	0.2500	0.19524 (4)	0.05818 (19)
I2	−0.04114 (7)	0.2500	0.52201 (4)	0.0760 (2)
N1	0.1340 (4)	0.4068 (2)	0.3767 (3)	0.0523 (10)
N2	−0.1010 (4)	0.4200 (2)	0.3583 (3)	0.0484 (10)
C1	0.2528 (5)	0.3975 (4)	0.3846 (4)	0.0640 (15)
H1A	0.2840	0.3481	0.3809	0.077*
C2	0.3299 (5)	0.4571 (4)	0.3978 (4)	0.0695 (16)
H2A	0.4116	0.4474	0.4025	0.083*
C3	0.2893 (5)	0.5313 (3)	0.4042 (4)	0.0603 (14)
C4	0.1643 (5)	0.5412 (3)	0.3960 (3)	0.0519 (12)
H4A	0.1312	0.5900	0.4006	0.062*
C5	0.0911 (4)	0.4788 (3)	0.3812 (3)	0.0436 (10)
C6	−0.0402 (4)	0.4862 (3)	0.3683 (3)	0.0428 (10)
C7	−0.0989 (5)	0.5568 (3)	0.3662 (3)	0.0493 (12)
H7A	−0.0552	0.6019	0.3730	0.059*
C8	−0.2214 (5)	0.5600 (3)	0.3542 (4)	0.0554 (13)
C9	−0.2824 (5)	0.4923 (3)	0.3449 (4)	0.0591 (14)
H9A	−0.3651	0.4923	0.3370	0.071*
C10	−0.2196 (5)	0.4238 (3)	0.3473 (4)	0.0554 (13)
H10A	−0.2622	0.3782	0.3410	0.066*
C11	0.3689 (6)	0.5995 (4)	0.4184 (5)	0.090 (2)
H11A	0.4424	0.5836	0.4484	0.136*
H11B	0.3293	0.6362	0.4593	0.136*
H11C	0.3859	0.6225	0.3567	0.136*
C12	−0.2839 (6)	0.6367 (3)	0.3491 (5)	0.0819 (19)
H12A	−0.2307	0.6741	0.3216	0.123*
H12B	−0.3067	0.6525	0.4132	0.123*
H12C	−0.3541	0.6323	0.3093	0.123*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cu1	0.0990 (6)	0.0276 (3)	0.0688 (5)	0.0008 (3)	0.0047 (4)	−0.0003 (3)
I1	0.0780 (4)	0.0420 (3)	0.0545 (3)	0.000	0.0019 (2)	0.000
I2	0.1387 (6)	0.0316 (3)	0.0577 (4)	0.000	0.0104 (3)	0.000
N1	0.069 (3)	0.038 (2)	0.051 (2)	0.0070 (19)	0.003 (2)	0.0018 (18)
N2	0.067 (3)	0.0310 (19)	0.048 (2)	−0.0040 (18)	0.0057 (19)	−0.0018 (16)
C1	0.076 (4)	0.060 (3)	0.056 (3)	0.017 (3)	−0.002 (3)	0.002 (3)
C2	0.051 (3)	0.099 (5)	0.058 (4)	0.011 (3)	−0.004 (3)	0.005 (3)
C3	0.064 (4)	0.066 (4)	0.051 (3)	−0.006 (3)	0.000 (2)	0.000 (3)
C4	0.066 (3)	0.042 (3)	0.048 (3)	−0.003 (2)	0.004 (2)	−0.003 (2)
C5	0.060 (3)	0.037 (2)	0.034 (2)	0.003 (2)	0.002 (2)	0.0001 (18)
C6	0.060 (3)	0.034 (2)	0.035 (2)	−0.001 (2)	0.004 (2)	0.0002 (18)
C7	0.062 (3)	0.032 (2)	0.054 (3)	−0.001 (2)	0.003 (2)	−0.005 (2)
C8	0.064 (3)	0.049 (3)	0.052 (3)	0.008 (2)	0.005 (2)	0.000 (2)
C9	0.052 (3)	0.068 (4)	0.057 (3)	−0.005 (3)	0.007 (2)	0.003 (3)
C10	0.068 (4)	0.048 (3)	0.050 (3)	−0.013 (3)	0.003 (3)	0.000 (2)
C11	0.064 (4)	0.106 (5)	0.101 (5)	−0.024 (4)	−0.003 (4)	−0.006 (4)
C12	0.079 (4)	0.062 (4)	0.105 (5)	0.020 (3)	0.002 (4)	−0.002 (4)

Geometric parameters (Å, º)

Cu1—N2	2.069 (4)	C4—H4A	0.9300
Cu1—N1	2.074 (4)	C5—C6	1.482 (7)
Cu1—Cu1^i	2.5274 (14)	C6—C7	1.394 (6)
Cu1—I1	2.5948 (9)	C7—C8	1.379 (7)
Cu1—I2	2.6307 (9)	C7—H7A	0.9300
N1—C1	1.341 (7)	C8—C9	1.369 (7)
N1—C5	1.345 (6)	C8—C12	1.509 (7)
N2—C10	1.334 (7)	C9—C10	1.385 (7)
N2—C6	1.347 (6)	C9—H9A	0.9300
C1—C2	1.361 (8)	C10—H10A	0.9300
C1—H1A	0.9300	C11—H11A	0.9600
C2—C3	1.374 (8)	C11—H11B	0.9600
C2—H2A	0.9300	C11—H11C	0.9600
C3—C4	1.411 (8)	C12—H12A	0.9600
C3—C11	1.497 (8)	C12—H12B	0.9600
C4—C5	1.375 (6)	C12—H12C	0.9600
N2—Cu1—N1	79.37 (16)	N1—C5—C4	122.2 (5)
N2—Cu1—Cu1^i	145.23 (12)	N1—C5—C6	115.4 (4)
N1—Cu1—Cu1^i	135.10 (11)	C4—C5—C6	122.4 (4)
N2—Cu1—I1	116.08 (11)	N2—C6—C7	121.2 (4)
N1—Cu1—I1	113.27 (12)	N2—C6—C5	115.8 (4)
Cu1^i—Cu1—I1	60.855 (17)	C7—C6—C5	123.0 (4)
N2—Cu1—I2	106.69 (11)	C8—C7—C6	120.3 (5)
N1—Cu1—I2	112.00 (12)	C8—C7—H7A	119.8
Cu1^i—Cu1—I2	61.290 (17)	C6—C7—H7A	119.8
I1—Cu1—I2	121.66 (3)	C9—C8—C7	118.0 (5)
Cu1—I1—Cu1^i	58.29 (3)	C9—C8—C12	122.0 (5)
Cu1^i—I2—Cu1	57.42 (3)	C7—C8—C12	120.0 (5)
C1—N1—C5	117.5 (5)	C8—C9—C10	119.4 (5)
C1—N1—Cu1	127.8 (4)	C8—C9—H9A	120.3
C5—N1—Cu1	114.8 (3)	C10—C9—H9A	120.3
C10—N2—C6	118.0 (4)	N2—C10—C9	123.2 (5)
C10—N2—Cu1	127.4 (3)	N2—C10—H10A	118.4
C6—N2—Cu1	114.6 (3)	C9—C10—H10A	118.4
N1—C1—C2	122.9 (5)	C3—C11—H11A	109.5
N1—C1—H1A	118.5	C3—C11—H11B	109.5
C2—C1—H1A	118.5	H11A—C11—H11B	109.5
C1—C2—C3	121.3 (5)	C3—C11—H11C	109.5
C1—C2—H2A	119.3	H11A—C11—H11C	109.5
C3—C2—H2A	119.3	H11B—C11—H11C	109.5
C2—C3—C4	115.8 (5)	C8—C12—H12A	109.5
C2—C3—C11	124.1 (6)	C8—C12—H12B	109.5
C4—C3—C11	120.0 (5)	H12A—C12—H12B	109.5
C5—C4—C3	120.2 (5)	C8—C12—H12C	109.5
C5—C4—H4A	119.9	H12A—C12—H12C	109.5
C3—C4—H4A	119.9	H12B—C12—H12C	109.5
N2—Cu1—I1—Cu1^i	−140.73 (13)	C1—C2—C3—C11	−179.8 (6)
N1—Cu1—I1—Cu1^i	130.02 (12)	C2—C3—C4—C5	−0.8 (8)
I2—Cu1—I1—Cu1^i	−8.08 (5)	C11—C3—C4—C5	178.8 (5)
N2—Cu1—I2—Cu1^i	144.44 (12)	C1—N1—C5—C4	−1.7 (7)
N1—Cu1—I2—Cu1^i	−130.53 (12)	Cu1—N1—C5—C4	177.8 (4)
I1—Cu1—I2—Cu1^i	8.04 (4)	C1—N1—C5—C6	177.7 (4)
N2—Cu1—N1—C1	−179.2 (5)	Cu1—N1—C5—C6	−2.7 (5)
Cu1^i—Cu1—N1—C1	6.2 (5)	C3—C4—C5—N1	1.8 (7)
I1—Cu1—N1—C1	−65.2 (5)	C3—C4—C5—C6	−177.6 (4)
I2—Cu1—N1—C1	77.0 (5)	C10—N2—C6—C7	−0.7 (7)
N2—Cu1—N1—C5	1.4 (3)	Cu1—N2—C6—C7	178.0 (3)
Cu1^i—Cu1—N1—C5	−173.3 (2)	C10—N2—C6—C5	179.4 (4)
I1—Cu1—N1—C5	115.3 (3)	Cu1—N2—C6—C5	−1.9 (5)
I2—Cu1—N1—C5	−102.5 (3)	N1—C5—C6—N2	3.1 (6)
N1—Cu1—N2—C10	178.9 (4)	C4—C5—C6—N2	−177.5 (4)
Cu1^i—Cu1—N2—C10	−7.7 (5)	N1—C5—C6—C7	−176.8 (4)
I1—Cu1—N2—C10	68.1 (4)	C4—C5—C6—C7	2.7 (7)
I2—Cu1—N2—C10	−71.1 (4)	N2—C6—C7—C8	0.3 (7)
N1—Cu1—N2—C6	0.3 (3)	C5—C6—C7—C8	−179.8 (4)
Cu1^i—Cu1—N2—C6	173.7 (2)	C6—C7—C8—C9	0.2 (8)
I1—Cu1—N2—C6	−110.5 (3)	C6—C7—C8—C12	−178.2 (5)
I2—Cu1—N2—C6	110.3 (3)	C7—C8—C9—C10	−0.3 (8)
C5—N1—C1—C2	0.6 (8)	C12—C8—C9—C10	178.1 (5)
Cu1—N1—C1—C2	−178.8 (4)	C6—N2—C10—C9	0.6 (7)
N1—C1—C2—C3	0.3 (9)	Cu1—N2—C10—C9	−177.9 (4)
C1—C2—C3—C4	−0.2 (8)	C8—C9—C10—N2	−0.1 (8)

Symmetry code: (i) x, −y+1/2, z.