supplementary materials


HTML versionpdf versioncif file3d viewstructure factorssupplementary materialsCIF check reportcited insimilar papers  retraction Open access

Acta Cryst. (2008). E64, m76    [ doi:10.1107/S1600536807062873 ]

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

S. Li, S.-B. Wang, F.-L. Zhang and K. Tang

Abstract top

In the title compound, [Co(N3)2(C6H6N4)2], the CoII atom lies on a centre of inversion and is bonded to two azide ions and two bidentate 2,2'-biimidizole ligands, giving a slightly distorted octahedral CoN6 coordination geometry. In the crystal structure, intermolecular N-H...N hydrogen bonds exist between the 2,2'-biimidizole ligands and the azide ions, linking the complexes into sheets.

Comment top

The imidazole moiety is of biochemical importance due to its presence in more than 200 metalloenzymes, such as carboxypeptidase A (CPA), carbonic anhydrase (CA), liver alcohol dehydrogenase (LADH), and superoxide dismutase (SOD) (Rees et al., 1983; Hardman & Lipscomb, 1984; Kuo & Makinen, 1982; Dworschak & Plapp, 1977).

In the title compound, the CoII atom occupies an inversion centre, and is hexacoordinated by six N atoms from two chelating ligands of H2bim (2,2'-biimidizole; C6H6N4) and two azide ions, showing a slightly distorted octahedral geometry (Fig. 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, intermolecular N—H···N hydrogen bonds between 2,2'-biimidizole ligands and azide ions link the complexes into sheets lying in the (002) planes (Fig. 2).

Related literature top

For related literature, see: Rees et al. (1983); Hardman & Lipscomb (1984); Kuo & Makinen (1982); Dworschak & Plapp (1977).

Experimental top

A mixture of CoCl2.2(H2O) (1 mmol), 2,2'-biimidazoline (2 mmol) and NaN3 (2 mmol) in 20 ml me thanol was refluxed for two hours. After cooling, the solution was filtered and the filtrate was evaporated naturally at room temperature. Two day later, red blocks of the title compound were obtained with a yield of 22%. Elemental analysis calculated: C 35.04, H 2.92, N 47.69%; found: C 35.01, H 2.96, N 47.65%.

Refinement top

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 Uiso(H) = 1.2Ueq(C/N).

Computing details top

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 top
[Figure 1] Fig. 1. The molecular structure with 30% probability displacement ellipsoids for non-H atoms. Atoms with suffix I are generated by the symmetry operator -x + 1/2, -y - 1/2, -z + 1.
[Figure 2] Fig. 2. Packing diagram showing intermolecular N—H···N hydrogen bonds.
Diazidobis(2,2'-biimidazole)cobalt(II) top
Crystal data top
[Co(N3)2(C6H6N4)2]F(000) = 836
Mr = 411.29Dx = 1.682 Mg m−3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 1501 reflections
a = 12.8085 (10) Åθ = 2.8–25.5°
b = 8.7632 (5) ŵ = 1.09 mm−1
c = 14.4793 (5) ÅT = 293 K
β = 91.913 (1)°Block, red
V = 1624.30 (17) Å30.28 × 0.22 × 0.20 mm
Z = 4
Data collection top
Bruker APEXII CCD
diffractometer		1501 independent reflections
Radiation source: fine-focus sealed tube1246 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.022
φ and ω scansθmax = 25.5°, θmin = 2.8°
Absorption correction: multi-scan
(SADABS; Bruker, 2001)		h = −1→15
Tmin = 0.750, Tmax = 0.811k = −1→10
1961 measured reflectionsl = −17→17
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.029Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.078H-atom parameters constrained
S = 1.00 w = 1/[σ2(Fo2) + (0.032P)2 + 0.7528P]
where P = (Fo2 + 2Fc2)/3
1501 reflections(Δ/σ)max = 0.016
124 parametersΔρmax = 0.24 e Å−3
0 restraintsΔρmin = −0.20 e Å−3
Crystal data top
[Co(N3)2(C6H6N4)2]V = 1624.30 (17) Å3
Mr = 411.29Z = 4
Monoclinic, C2/cMo Kα radiation
a = 12.8085 (10) ŵ = 1.09 mm−1
b = 8.7632 (5) ÅT = 293 K
c = 14.4793 (5) Å0.28 × 0.22 × 0.20 mm
β = 91.913 (1)°
Data collection top
Bruker APEXII CCD
diffractometer		1501 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2001)		1246 reflections with I > 2σ(I)
Tmin = 0.750, Tmax = 0.811Rint = 0.022
1961 measured reflectionsθmax = 25.5°
Refinement top
R[F2 > 2σ(F2)] = 0.029H-atom parameters constrained
wR(F2) = 0.078Δρmax = 0.24 e Å−3
S = 1.00Δρmin = −0.20 e Å−3
1501 reflectionsAbsolute structure: ?
124 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Special details top

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 (Å2) top
xyzUiso*/Ueq
Co10.2500−0.25000.50000.04053 (15)
C10.08433 (18)−0.0620 (3)0.36274 (15)0.0523 (6)
H10.0724−0.12980.31410.063*
C20.03681 (18)0.0756 (3)0.37190 (15)0.0528 (6)
H2−0.01260.11940.33150.063*
C30.14622 (17)0.0371 (2)0.48932 (14)0.0433 (5)
C40.21008 (17)0.0440 (2)0.57427 (14)0.0437 (5)
C50.32254 (19)−0.0319 (3)0.67815 (16)0.0535 (6)
H50.3710−0.09240.71030.064*
C60.29414 (19)0.1097 (3)0.70284 (16)0.0556 (6)
H60.31820.16440.75430.067*
N10.15295 (14)−0.0854 (2)0.43678 (12)0.0463 (4)
N20.26893 (14)−0.0737 (2)0.59794 (12)0.0475 (4)
N30.38297 (15)−0.1637 (2)0.42685 (13)0.0521 (5)
N40.39621 (15)−0.0323 (2)0.42133 (13)0.0507 (5)
N50.41050 (18)0.0987 (2)0.41471 (16)0.0668 (6)
N60.22221 (15)0.1566 (2)0.63634 (12)0.0506 (5)
H6A0.19050.24320.63480.061*
N70.07654 (14)0.1364 (2)0.45280 (12)0.0484 (4)
H7A0.05980.22300.47610.058*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Co10.0437 (2)0.0363 (2)0.0409 (2)0.01142 (17)−0.00752 (16)−0.00494 (16)
C10.0524 (13)0.0580 (14)0.0459 (12)0.0139 (11)−0.0072 (10)−0.0039 (10)
C20.0522 (13)0.0585 (15)0.0473 (12)0.0164 (11)−0.0055 (10)0.0043 (11)
C30.0431 (11)0.0417 (12)0.0452 (11)0.0082 (9)0.0015 (9)0.0009 (9)
C40.0455 (11)0.0400 (11)0.0456 (11)0.0047 (10)0.0022 (9)−0.0028 (9)
C50.0556 (13)0.0536 (14)0.0503 (12)0.0048 (11)−0.0100 (10)−0.0019 (11)
C60.0618 (14)0.0551 (15)0.0491 (12)−0.0004 (12)−0.0088 (11)−0.0091 (11)
N10.0474 (10)0.0460 (11)0.0450 (9)0.0112 (9)−0.0048 (8)−0.0042 (8)
N20.0507 (10)0.0442 (10)0.0472 (10)0.0078 (9)−0.0065 (8)−0.0044 (8)
N30.0554 (11)0.0401 (11)0.0605 (11)0.0096 (9)−0.0019 (9)−0.0036 (9)
N40.0488 (11)0.0505 (13)0.0522 (11)0.0128 (9)−0.0073 (9)−0.0070 (9)
N50.0717 (14)0.0417 (12)0.0860 (15)0.0073 (11)−0.0101 (12)−0.0065 (11)
N60.0588 (11)0.0415 (11)0.0514 (10)0.0074 (9)−0.0008 (9)−0.0070 (8)
N70.0531 (11)0.0425 (10)0.0497 (10)0.0148 (9)0.0018 (8)0.0005 (8)
Geometric parameters (Å, º) top
Co1—N12.0945 (17)C3—C41.455 (3)
Co1—N1i2.0945 (17)C4—N21.316 (3)
Co1—N2i2.1055 (18)C4—N61.341 (3)
Co1—N22.1055 (18)C5—C61.344 (3)
Co1—N32.172 (2)C5—N21.379 (3)
Co1—N3i2.172 (2)C5—H50.930
C1—C21.359 (3)C6—N61.373 (3)
C1—N11.379 (3)C6—H60.930
C1—H10.930N3—N41.167 (3)
C2—N71.370 (3)N4—N51.167 (3)
C2—H20.930N6—H6A0.860
C3—N11.320 (3)N7—H7A0.860
C3—N71.343 (3)
N1—Co1—N1i180.00 (8)N2—C4—N6110.49 (19)
N1—Co1—N2i99.06 (7)N2—C4—C3119.23 (19)
N1i—Co1—N2i80.94 (7)N6—C4—C3130.3 (2)
N1—Co1—N280.94 (7)C6—C5—N2109.7 (2)
N1i—Co1—N299.06 (7)C6—C5—H5125.1
N2i—Co1—N2180.0N2—C5—H5125.1
N1—Co1—N390.61 (7)C5—C6—N6105.7 (2)
N1i—Co1—N389.39 (7)C5—C6—H6127.1
N2i—Co1—N390.10 (7)N6—C6—H6127.1
N2—Co1—N389.90 (7)C3—N1—C1105.96 (18)
N1—Co1—N3i89.39 (7)C3—N1—Co1110.93 (13)
N1i—Co1—N3i90.61 (7)C1—N1—Co1142.74 (16)
N2i—Co1—N3i89.90 (7)C4—N2—C5106.00 (19)
N2—Co1—N3i90.10 (7)C4—N2—Co1110.33 (14)
N3—Co1—N3i180.00 (6)C5—N2—Co1143.64 (16)
C2—C1—N1109.4 (2)N4—N3—Co1119.70 (17)
C2—C1—H1125.3N5—N4—N3179.0 (3)
N1—C1—H1125.3C4—N6—C6108.01 (19)
C1—C2—N7105.91 (19)C4—N6—H6A126.0
C1—C2—H2127.0C6—N6—H6A126.0
N7—C2—H2127.0C3—N7—C2107.90 (18)
N1—C3—N7110.83 (19)C3—N7—H7A126.0
N1—C3—C4118.37 (18)C2—N7—H7A126.1
N7—C3—C4130.8 (2)
Symmetry code: (i) −x+1/2, −y−1/2, −z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N6—H6A···N5ii0.862.012.819 (3)156
N7—H7A···N5ii0.862.253.012 (3)148
N7—H7A···N3iii0.862.553.049 (3)118
Symmetry codes: (ii) −x+1/2, −y+1/2, −z+1; (iii) x−1/2, y+1/2, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N6—H6A···N5i0.862.012.819 (3)156.1
N7—H7A···N5i0.862.253.012 (3)148.3
N7—H7A···N3ii0.862.553.049 (3)117.6
Symmetry codes: (i) −x+1/2, −y+1/2, −z+1; (ii) x−1/2, y+1/2, z.
Acknowledgements top

The authors are grateful for financial support from Henan University (grant No. 05YBGG013)

references
References top

Bruker (2001). SADABS, SAINT-Plus and SHELXTL. Bruker AXS Inc., Madison, Wisconsin, USA.

Bruker (2004). APEX2. Bruker AXS Inc., Madison, Wisconsin, USA.

Dworschak, R. T. & Plapp, B. V. (1977). Biochemistry, 16, 111–117.

Hardman, K. D. & Lipscomb, W. N. (1984). J. Am. Chem. Soc. 106, 463–469.

Kuo, L. C. & Makinen, M. W. (1982). J. Biol. Chem. 257, 24–35.

Rees, D. C., Lewis, M. & Lipscomb, W. N. (1983). J. Mol. Biol. 168, 367–387.

Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany.