Diaqua­bis[5-(pyrazin-2-yl)tetra­zolato]cobalt(II)

In the title complex, [Co(C₅H₃N₃)₂(H₂O)₂], prepared in a one-pot synthesis, the Co^II atom (site symmetry ), is coordinated by four N atoms from two 5-(2-pyrazin­yl)tetra­zolate ligands and by two water mol­ecules in a distorted trans-CoO₂N₄ octa­hedral geometry. A supra­molecular network is formed via inter­molecular O—H...N hydrogen bonds.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.034
• wR factor = 0.083
• Data-to-parameter ratio = 14.0

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT232_ALERT_2_C Hirshfeld Test Diff (M-X)  Co1    -   N1      ..       5.41 su

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 Co1         (2)       1.78
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          3

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

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 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
   0 ALERT type 4 Improvement, methodology, query or suggestion
   1 ALERT type 5 Informative message, check

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S1. Comment

The design, synthesis, characterization, and properties of supramolecular networks formed by using functionalized organic molecules as bridges between metal centers are of great interest (Rizk et al., 2005; Eddaoudi et al., 2001). The reports on tetrazoles is expanding rapidly, since tetrazoles have an important role in coordination chemistry as a ligand (Deng et al., 2006). Recently, 5-substituted 1H-tetrazoles have been synthesized by a facile approach (Demko & Sharpless, 2001a, 2001b). In the general reaction, the tetrazoles are prepared by the addition of azide to nitriles in water with the aid of a lewis acid such a Zn²⁺. In this paper, we selected 2-cyanopyrazine, NaN₃ and a Lewis acid CoCl₂ as reagent, to yield in one step the mononuclear structure (I) under hydrothermal condition.

In (I), the Co^II atom, located on an inversion center, is coordinated by four N atoms from two 5-(2-pyrazinyl)tetrazolate ligands and two water molecules in a distorted octahedral geometry (Fig. 1; Table 1). In the ligand, the pyrazinyl and tetrazolyl rings are almost coplanar, with a dihedral angle of 3.53 (4)°. Intermolecular O—H···N hydrogen bonds (Table 2) form a supramolecular network (Fig. 2).

Related literature

For related literature, see: Demko & Sharpless (2001a, 2001b); Deng et al. (2007); Eddaoudi et al. (2001); Rizk et al. (2005).

S2. Experimental

Hydrothermal treatment of CoCl₂.6H₂O (1.0 mmol, 0.237 g), 2-cyanopyrazine (1 mmol, 0.105 g), Na_N3 (1 mmol, 0.065 g), and water (3 ml) over 50 h at 422 K yielded red prisms of (I) (yield 78%).

S3. Refinement

The water H atoms were located in a difference Fourier map and their positions were freely refined with U_iso(H) = 1.2U_eq(O). The other H atoms were placed

in calculated positions (C—H = 0.93 Å) refined using a riding model with U_iso(H) = 1.2U_eq(C).

Computing details

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

Figures

	Fig. 1. The structure of (I), showing the atomic numbering scheme. Non-H atoms are shown as 50% probability displacement ellipsoids. Unlabelled atoms are related to the labelled atoms by the symmetry operator (1 - x, 1 - y, -z).
	Fig. 2. A packing diagram of (I). Hydrogen bonds are depicted as broken lines.

Diaquabis[5-(pyrazin-2-yl)tetrazolate]cobalt(II)

Crystal data

[Co(C5H3N3)2(H2O)2]	F(000) = 394
Mr = 389.23	Dx = 1.809 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 5700 reflections
a = 6.0676 (1) Å	θ = 1.7–28.0°
b = 11.4221 (2) Å	µ = 1.24 mm^−1
c = 10.7096 (2) Å	T = 293 K
β = 105.652 (1)°	Prism, red
V = 714.70 (2) Å^3	0.18 × 0.16 × 0.15 mm
Z = 2

Data collection

Bruker APEXII area-detector diffractometer	1693 independent reflections
Radiation source: fine-focus sealed tube	1325 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.035
φ and ω scans	θmax = 27.9°, θmin = 2.7°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −7→7
Tmin = 0.808, Tmax = 0.836	k = −15→14
6011 measured reflections	l = −14→12

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)] = 0.034	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.083	H atoms treated by a mixture of independent and constrained refinement
S = 1.06	w = 1/[σ^2(Fo^2) + (0.0392P)^2 + 0.1286P] where P = (Fo^2 + 2Fc^2)/3
1693 reflections	(Δ/σ)max < 0.001
121 parameters	Δρmax = 0.33 e Å^−3
3 restraints	Δρmin = −0.30 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
C1	0.5209 (3)	0.24786 (18)	0.0722 (2)	0.0292 (5)
C2	0.4676 (4)	0.13095 (19)	0.0833 (3)	0.0422 (6)
H2	0.5804	0.0813	0.1314	0.051*
C3	0.1084 (4)	0.1622 (2)	−0.0407 (3)	0.0437 (6)
H3	−0.0379	0.1351	−0.0813	0.052*
C4	0.1588 (4)	0.2787 (2)	−0.0534 (2)	0.0355 (5)
H4	0.0459	0.3277	−0.1025	0.043*
C5	0.7458 (3)	0.29806 (18)	0.1328 (2)	0.0292 (5)
Co1	0.5000	0.5000	0.0000	0.02720 (14)
H1W	0.305 (3)	0.5142 (18)	0.182 (2)	0.053*
H2W	0.457 (4)	0.5988 (15)	0.212 (2)	0.053*
N1	0.3655 (3)	0.32279 (14)	0.00284 (17)	0.0286 (4)
N2	0.2619 (3)	0.08721 (18)	0.0278 (2)	0.0507 (6)
N3	0.9254 (3)	0.24591 (16)	0.21020 (19)	0.0355 (4)
N4	1.0867 (3)	0.32889 (18)	0.2402 (2)	0.0427 (5)
N5	1.0062 (3)	0.42684 (17)	0.1815 (2)	0.0393 (5)
N6	0.7895 (3)	0.41001 (15)	0.11191 (18)	0.0306 (4)
O1W	0.4169 (3)	0.53856 (16)	0.17002 (18)	0.0428 (4)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0287 (11)	0.0243 (10)	0.0337 (12)	0.0012 (8)	0.0066 (9)	0.0007 (9)
C2	0.0394 (13)	0.0269 (12)	0.0563 (17)	0.0021 (10)	0.0057 (12)	0.0062 (11)
C3	0.0346 (12)	0.0398 (14)	0.0532 (16)	−0.0101 (10)	0.0061 (12)	−0.0053 (12)
C4	0.0295 (11)	0.0368 (12)	0.0378 (13)	−0.0004 (9)	0.0053 (10)	−0.0005 (10)
C5	0.0292 (11)	0.0241 (10)	0.0343 (12)	0.0034 (8)	0.0086 (9)	0.0032 (9)
Co1	0.0264 (2)	0.0196 (2)	0.0336 (2)	−0.00012 (16)	0.00481 (16)	0.00184 (17)
N1	0.0296 (9)	0.0247 (9)	0.0310 (10)	0.0007 (7)	0.0072 (8)	0.0009 (7)
N2	0.0447 (12)	0.0308 (11)	0.0706 (16)	−0.0105 (9)	0.0055 (11)	0.0010 (11)
N3	0.0286 (9)	0.0329 (10)	0.0419 (11)	0.0020 (8)	0.0041 (8)	0.0081 (9)
N4	0.0323 (10)	0.0448 (12)	0.0461 (12)	−0.0013 (9)	0.0024 (9)	0.0063 (10)
N5	0.0310 (10)	0.0365 (11)	0.0465 (12)	−0.0049 (8)	0.0039 (9)	0.0003 (9)
N6	0.0249 (9)	0.0261 (9)	0.0382 (11)	−0.0014 (7)	0.0042 (8)	0.0007 (8)
O1W	0.0455 (10)	0.0381 (9)	0.0503 (11)	−0.0154 (8)	0.0225 (9)	−0.0143 (8)

Geometric parameters (Å, º)

C1—N1	1.340 (2)	Co1—O1W	2.0638 (18)
C1—C2	1.386 (3)	Co1—O1W^i	2.0638 (18)
C1—C5	1.461 (3)	Co1—N6^i	2.1076 (17)
C2—N2	1.327 (3)	Co1—N6	2.1076 (17)
C2—H2	0.9300	Co1—N1^i	2.1856 (16)
C3—N2	1.330 (3)	Co1—N1	2.1856 (16)
C3—C4	1.381 (3)	N3—N4	1.338 (3)
C3—H3	0.9300	N4—N5	1.311 (3)
C4—N1	1.335 (3)	N5—N6	1.339 (2)
C4—H4	0.9300	O1W—H1W	0.777 (15)
C5—N3	1.320 (3)	O1W—H2W	0.819 (15)
C5—N6	1.337 (3)
N1—C1—C2	121.15 (19)	O1W^i—Co1—N1^i	90.25 (7)
N1—C1—C5	115.39 (18)	N6^i—Co1—N1^i	78.31 (6)
C2—C1—C5	123.46 (19)	N6—Co1—N1^i	101.69 (6)
N2—C2—C1	122.5 (2)	O1W—Co1—N1	90.25 (7)
N2—C2—H2	118.8	O1W^i—Co1—N1	89.75 (7)
C1—C2—H2	118.8	N6^i—Co1—N1	101.69 (6)
N2—C3—C4	122.3 (2)	N6—Co1—N1	78.31 (6)
N2—C3—H3	118.9	N1^i—Co1—N1	180.0
C4—C3—H3	118.9	C4—N1—C1	116.36 (18)
N1—C4—C3	121.7 (2)	C4—N1—Co1	130.69 (15)
N1—C4—H4	119.2	C1—N1—Co1	112.94 (13)
C3—C4—H4	119.2	C2—N2—C3	116.0 (2)
N3—C5—N6	111.69 (19)	C5—N3—N4	104.92 (17)
N3—C5—C1	128.00 (19)	N5—N4—N3	109.61 (17)
N6—C5—C1	120.31 (18)	N4—N5—N6	109.10 (17)
O1W—Co1—O1W^i	180.0	C5—N6—N5	104.68 (17)
O1W—Co1—N6^i	91.90 (7)	C5—N6—Co1	112.91 (13)
O1W^i—Co1—N6^i	88.10 (7)	N5—N6—Co1	142.10 (14)
O1W—Co1—N6	88.10 (7)	Co1—O1W—H1W	120.3 (18)
O1W^i—Co1—N6	91.90 (7)	Co1—O1W—H2W	123.5 (16)
N6^i—Co1—N6	180.0	H1W—O1W—H2W	111 (2)
O1W—Co1—N1^i	89.75 (7)

Symmetry code: (i) −x+1, −y+1, −z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1W—H1W···N5^ii	0.78 (2)	2.07 (2)	2.832 (2)	168 (2)
O1W—H2W···N3^iii	0.82 (2)	1.93 (2)	2.740 (2)	171 (2)

Symmetry codes: (ii) x−1, y, z; (iii) −x+3/2, y+1/2, −z+1/2.