Retracted: Diazido­bis(2,2′-biimidazole)copper(II)

In the title compound, [Cu(N₃)₂(C₆H₆N₄)₂], the Cu atom (site symmetry ) is bonded to two azide ions and two bidentate biimidizole ligands, resulting in a slightly distorted octa­hedral CuN₆ geometry for the metal. In the crystal structure, N—H...N hydrogen bonds help to consolidate the packing.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.005 Å
• R factor = 0.037
• wR factor = 0.128
• Data-to-parameter ratio = 11.9

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT062_ALERT_4_C Rescale T(min) & T(max) by .....................       0.98
PLAT180_ALERT_3_C Check Cell Rounding: # of Values Ending with 0 =          3
PLAT230_ALERT_2_C Hirshfeld Test Diff for    N1     -   N2      ..       6.12 su
PLAT230_ALERT_2_C Hirshfeld Test Diff for    N2     -   N3      ..       5.39 su
PLAT790_ALERT_4_C Centre of Gravity not Within Unit Cell: Resd.  #          1
              C12 H12 Cu N14

Alert level G
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_G Check the Reported _diffrn_ambient_temperature .        293 K
PLAT794_ALERT_5_G Check Predicted Bond Valency for Cu1         (1)       1.23

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

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

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S1. Comment

In recent years, N-heterocycle ligands have been widely used as polydentate ligands which show various metal chelation reactions (Scapin et al., 1997; Okabe & Oya, 2000; Serre et al., 2005). In this paper, we report the structure of the title compound, (I).

In compound (I), the Cu ion occupies an inversion centre, and is hexacoordinated by six N atoms from two chelating ligands of H₂bim (biimidizole; C₆H₆N₄) and two azide ions, showing a slightly distorted octahedral geometry (Table 1). The four N atoms from the chelating H₂bim consist of the base and the other two N atoms from two azide ions ocupy the axial positions. In the crystal of (I), N—H···N hydrogen bonds, one of which is bifurcated (Table 2), help to consolidate the packing.

Related literature

For related literature, see: Scapin et al. (1997); Okabe & Oya (2000); Serre et al. (2005).

S2. Experimental

A mixture of CuCl_2.2(H₂O) (1 mmoL), 2,2'-biimidazoline (2 mmoL) and Na₃N₃ (2 mmoL) in 20 ml me thanol was reflued for two hours. The above cooled solution was filterated and the filtrate was evaporated naturally at room temperature. Two day later, blue blocks of (I) were obtained with a yield of 31%. Anal. Calc. for C₁₂H₁₂CuN₁₄: C 40.39, H 3.37, N 47.13%; Found: C 40.32, H 3.42, N 47.08%.

S3. Refinement

All H atoms were placed in calculated positions with C—H = 0.93 Å and N—H = 0.86 Å and refined as riding with U_iso(H) = 1.2U_eq(carrier).

Computing details

Data collection: APEX2 (Bruker, 2004); cell refinement: SAINT-Plus (Bruker, 2001); data reduction: SAINT-Plus (Bruker, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 2001); software used to prepare material for publication: SHELXTL (Bruker, 2001).

Figures

Fig. 1. The molecular structure of (I), drawn with 30% probability displacement ellipsoids for the non-hydrogen atoms. Atoms with suffix I are at the symmetry position (-x + 1/2, -y - 1/2, -z + 1).

Diazidobis(2,2'-biimidazole)copper(II)

Crystal data

[Cu(N3)2(C6H6N4)2]	F(000) = 844
Mr = 415.90	Dx = 1.749 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 1479 reflections
a = 12.457 (1) Å	θ = 2.8–25.6°
b = 9.0112 (5) Å	µ = 1.42 mm^−1
c = 14.081 (1) Å	T = 293 K
β = 91.84 (1)°	Block, blue
V = 1579.80 (19) Å^3	0.43 × 0.28 × 0.22 mm
Z = 4

Data collection

Bruker APEXII CCD diffractometer	1479 independent reflections
Radiation source: fine-focus sealed tube	1233 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.022
φ and ω scans	θmax = 25.6°, θmin = 2.8°
Absorption correction: multi-scan (SADABS; Bruker, 2001)	h = −1→15
Tmin = 0.581, Tmax = 0.746	k = −1→10
1929 measured reflections	l = −17→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)] = 0.037	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.128	H-atom parameters constrained
S = 1.00	w = 1/[σ^2(Fo^2) + (0.0836P)^2 + 1.7026P] where P = (Fo^2 + 2Fc^2)/3
1479 reflections	(Δ/σ)max < 0.001
124 parameters	Δρmax = 0.33 e Å^−3
0 restraints	Δρmin = −0.33 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	0.2500	−0.2500	0.5000	0.0416 (2)
C1	0.3231 (3)	−0.0321 (4)	0.6784 (2)	0.0474 (8)
H1	0.3724	−0.0908	0.7122	0.057*
C2	0.2945 (3)	0.1098 (4)	0.7029 (2)	0.0491 (8)
H2	0.3203	0.1633	0.7553	0.059*
C3	0.2097 (2)	0.0439 (3)	0.5743 (2)	0.0374 (6)
C4	0.1460 (2)	0.0370 (3)	0.4894 (2)	0.0378 (7)
C5	0.0370 (3)	0.0753 (4)	0.3717 (2)	0.0462 (8)
H5	−0.0130	0.1180	0.3296	0.055*
C6	0.0846 (3)	−0.0622 (4)	0.3624 (2)	0.0462 (8)
H6	0.0715	−0.1281	0.3126	0.055*
N1	0.3825 (2)	−0.1638 (3)	0.42674 (19)	0.0447 (6)
N2	0.3960 (2)	−0.0324 (3)	0.42134 (18)	0.0443 (7)
N3	0.4102 (3)	0.0983 (3)	0.4146 (2)	0.0578 (8)
N4	0.2686 (2)	−0.0741 (3)	0.59778 (17)	0.0408 (6)
N5	0.2220 (2)	0.1569 (3)	0.63632 (19)	0.0439 (6)
H5A	0.1901	0.2416	0.6340	0.053*
N6	0.0766 (2)	0.1363 (3)	0.45316 (18)	0.0413 (6)
H6A	0.0605	0.2212	0.4767	0.050*
N7	0.1528 (2)	−0.0858 (3)	0.43695 (17)	0.0394 (6)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cu1	0.0427 (4)	0.0416 (4)	0.0399 (4)	0.0115 (2)	−0.0075 (2)	−0.0051 (2)
C1	0.0473 (17)	0.053 (2)	0.0409 (16)	0.0051 (15)	−0.0089 (13)	−0.0010 (14)
C2	0.0541 (19)	0.054 (2)	0.0386 (16)	−0.0005 (16)	−0.0074 (14)	−0.0082 (14)
C3	0.0370 (14)	0.0393 (16)	0.0360 (14)	0.0045 (12)	0.0027 (12)	−0.0025 (12)
C4	0.0337 (14)	0.0409 (17)	0.0388 (15)	0.0068 (12)	0.0020 (11)	0.0010 (12)
C5	0.0424 (16)	0.056 (2)	0.0403 (16)	0.0164 (15)	−0.0036 (13)	0.0046 (14)
C6	0.0423 (16)	0.058 (2)	0.0382 (15)	0.0133 (15)	−0.0063 (13)	−0.0035 (14)
N1	0.0440 (14)	0.0404 (16)	0.0495 (15)	0.0094 (12)	−0.0012 (12)	−0.0033 (12)
N2	0.0385 (14)	0.0527 (19)	0.0412 (14)	0.0130 (13)	−0.0071 (11)	−0.0069 (12)
N3	0.0591 (18)	0.0401 (17)	0.073 (2)	0.0079 (14)	−0.0097 (15)	−0.0072 (15)
N4	0.0421 (14)	0.0420 (15)	0.0380 (13)	0.0069 (12)	−0.0054 (11)	−0.0054 (11)
N5	0.0477 (15)	0.0408 (15)	0.0431 (13)	0.0075 (12)	−0.0005 (11)	−0.0058 (12)
N6	0.0423 (14)	0.0414 (14)	0.0401 (13)	0.0134 (12)	0.0011 (11)	0.0013 (11)
N7	0.0369 (13)	0.0442 (15)	0.0368 (13)	0.0107 (11)	−0.0041 (10)	−0.0038 (11)

Geometric parameters (Å, º)

Cu1—N7^i	2.092 (2)	C3—C4	1.415 (4)
Cu1—N7	2.092 (2)	C4—N7	1.335 (4)
Cu1—N4^i	2.107 (2)	C4—N6	1.334 (4)
Cu1—N4	2.107 (2)	C5—N6	1.350 (4)
Cu1—N1	2.122 (3)	C5—C6	1.381 (5)
Cu1—N1^i	2.122 (3)	C5—H5	0.9300
C1—N4	1.358 (4)	C6—N7	1.346 (4)
C1—C2	1.374 (5)	C6—H6	0.9300
C1—H1	0.9300	N1—N2	1.199 (4)
C2—N5	1.349 (4)	N2—N3	1.196 (4)
C2—H2	0.9300	N5—H5A	0.8600
C3—N4	1.327 (4)	N6—H6A	0.8600
C3—N5	1.346 (4)
N7^i—Cu1—N7	180.0	N7—C4—N6	113.3 (3)
N7^i—Cu1—N4^i	78.17 (10)	N7—C4—C3	117.4 (3)
N7—Cu1—N4^i	101.83 (10)	N6—C4—C3	129.3 (3)
N7^i—Cu1—N4	101.83 (10)	N6—C5—C6	107.4 (3)
N7—Cu1—N4	78.17 (10)	N6—C5—H5	126.3
N4^i—Cu1—N4	180.0	C6—C5—H5	126.3
N7^i—Cu1—N1	90.95 (10)	N7—C6—C5	109.2 (3)
N7—Cu1—N1	89.05 (10)	N7—C6—H6	125.4
N4^i—Cu1—N1	91.62 (10)	C5—C6—H6	125.4
N4—Cu1—N1	88.38 (10)	N2—N1—Cu1	120.3 (2)
N7^i—Cu1—N1^i	89.05 (10)	N3—N2—N1	178.9 (4)
N7—Cu1—N1^i	90.95 (10)	C3—N4—C1	104.0 (3)
N4^i—Cu1—N1^i	88.38 (10)	C3—N4—Cu1	113.09 (19)
N4—Cu1—N1^i	91.62 (10)	C1—N4—Cu1	142.9 (2)
N1—Cu1—N1^i	180.0	C3—N5—C2	105.8 (3)
N4—C1—C2	110.0 (3)	C3—N5—H5A	127.1
N4—C1—H1	125.0	C2—N5—H5A	127.1
C2—C1—H1	125.0	C4—N6—C5	105.5 (3)
N5—C2—C1	107.0 (3)	C4—N6—H6A	127.3
N5—C2—H2	126.5	C5—N6—H6A	127.3
C1—C2—H2	126.5	C4—N7—C6	104.6 (3)
N4—C3—N5	113.2 (3)	C4—N7—Cu1	113.43 (19)
N4—C3—C4	117.7 (3)	C6—N7—Cu1	141.7 (2)
N5—C3—C4	129.0 (3)

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
N5—H5A···N3^ii	0.86	2.01	2.831 (4)	158
N6—H6A···N1^iii	0.86	2.53	3.029 (4)	118
N6—H6A···N3^ii	0.86	2.26	3.032 (4)	150

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