Diaqua­bis(2-methyl­pyrazine-5-carboxyl­ato)cobalt(II)

The title compound, [Co(C₆H₆N₂O₂)₂(H₂O)₂], was obtained from Co(CH₃COO)₂·6H₂O and 2-methyl­pyrazine-5-carboxylic acid. The crystal structure reveals that the Co atom is located on a crystallographic inversion center and is six-coordinated in a distorted octa­hedral geometry by 2-methyl­pyrazine-5-carboxyl­ate anions and water mol­ecules. The structure is stabilized both by hydrogen bonds forming a two-dimensional network parallel to the ab plane and by π–π stacking inter­actions between the 2-methyl­pyrazine-5-carboxyl­ate ligands.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.030
• wR factor = 0.084
• Data-to-parameter ratio = 14.1

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT154_ALERT_1_C The su's on the Cell Angles are Equal (x 10000)        3000 Deg.
PLAT232_ALERT_2_C Hirshfeld Test Diff (M-X)  Co1    -   O2      ..       5.18 su
PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor ....       2.27
PLAT380_ALERT_4_C Check Incorrectly? Oriented X(sp2)-Methyl Moiety         C5
PLAT720_ALERT_4_C Number of Unusual/Non-Standard Label(s) ........          2

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

   1 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
   0 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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Computing details

Data collection: SMART (Bruker, 2000); cell refinement: SMART; data reduction: SAINT (Bruker, 2000); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997a); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997a); molecular graphics: SHELXTL (Sheldrick, 1997b); software used to prepare material for publication: SHELXTL.

Diaquabis(2-methylpyrazine-5-carboxylato)cobalt(II)

Crystal data

[Co(C6H6N2O2)2(H2O)2]	Z = 1
Mr = 369.20	F(000) = 189
Triclinic, P1	Dx = 1.672 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 5.1051 (10) Å	Cell parameters from 2378 reflections
b = 6.3653 (13) Å	θ = 2.2–27.5°
c = 12.281 (3) Å	µ = 1.21 mm^−1
α = 103.53 (3)°	T = 298 K
β = 91.06 (3)°	Block, red
γ = 108.28 (3)°	0.29 × 0.19 × 0.15 mm
V = 366.59 (16) Å^3

Data collection

Bruker APEX-II CCD area-detector diffractometer	1627 independent reflections
Radiation source: fine-focus sealed tube	1569 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.011
φ and ω scans	θmax = 28.1°, θmin = 1.7°
Absorption correction: multi-scan (SADABS; Bruker, 1998)	h = −6→5
Tmin = 0.761, Tmax = 0.836	k = −8→7
2378 measured reflections	l = −16→16

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.030	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.084	w = 1/[σ^2(Fo^2) + (0.0519P)^2 + 0.1476P] where P = (Fo^2 + 2Fc^2)/3
S = 1.05	(Δ/σ)max = 0.024
1627 reflections	Δρmax = 0.38 e Å^−3
115 parameters	Δρmin = −0.28 e Å^−3
0 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.023 (6)

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
Co1	0.0000	0.5000	0.5000	0.02631 (15)
N1	0.0927 (3)	0.4735 (3)	0.33096 (13)	0.0283 (3)
C1	0.0028 (4)	0.6109 (3)	0.28416 (16)	0.0288 (4)
N2	0.1757 (5)	0.4895 (4)	0.11013 (16)	0.0470 (5)
C3	0.2597 (4)	0.3504 (4)	0.15644 (17)	0.0358 (4)
C4	0.2208 (4)	0.3433 (3)	0.26732 (17)	0.0330 (4)
H4A	0.2853	0.2459	0.2978	0.040*
C5	0.3975 (6)	0.1972 (5)	0.0849 (2)	0.0508 (6)
H5A	0.4071	0.2241	0.0111	0.076*
H5B	0.2918	0.0403	0.0792	0.076*
H5C	0.5815	0.2296	0.1188	0.076*
C2	0.0463 (5)	0.6189 (4)	0.17453 (18)	0.0430 (5)
H2A	−0.0163	0.7174	0.1442	0.052*
O2	−0.1853 (3)	0.7186 (2)	0.45461 (11)	0.0309 (3)
O1	−0.2477 (4)	0.8709 (3)	0.31392 (13)	0.0417 (4)
C6	−0.1560 (4)	0.7479 (3)	0.35608 (16)	0.0284 (4)
O1W	0.3649 (3)	0.7735 (3)	0.55874 (15)	0.0392 (4)
H1WA	0.497 (6)	0.792 (4)	0.525 (2)	0.037 (7)*
H1WB	0.355 (6)	0.888 (5)	0.590 (2)	0.041 (7)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Co1	0.0318 (2)	0.0293 (2)	0.0245 (2)	0.01763 (15)	0.01167 (13)	0.00822 (14)
N1	0.0324 (8)	0.0310 (8)	0.0264 (8)	0.0160 (6)	0.0109 (6)	0.0081 (6)
C1	0.0322 (9)	0.0310 (9)	0.0271 (9)	0.0148 (7)	0.0104 (7)	0.0080 (7)
N2	0.0590 (12)	0.0649 (13)	0.0293 (9)	0.0344 (10)	0.0181 (8)	0.0145 (9)
C3	0.0362 (10)	0.0437 (11)	0.0289 (9)	0.0183 (9)	0.0127 (8)	0.0037 (8)
C4	0.0373 (10)	0.0364 (10)	0.0319 (10)	0.0214 (8)	0.0116 (8)	0.0078 (8)
C5	0.0558 (14)	0.0594 (15)	0.0410 (12)	0.0312 (12)	0.0215 (11)	0.0013 (11)
C2	0.0601 (14)	0.0548 (13)	0.0303 (10)	0.0354 (11)	0.0146 (9)	0.0178 (9)
O2	0.0372 (7)	0.0341 (7)	0.0297 (7)	0.0215 (6)	0.0145 (5)	0.0093 (5)
O1	0.0589 (10)	0.0407 (8)	0.0387 (8)	0.0328 (7)	0.0106 (7)	0.0122 (6)
C6	0.0306 (9)	0.0265 (8)	0.0309 (9)	0.0144 (7)	0.0070 (7)	0.0054 (7)
O1W	0.0347 (8)	0.0327 (8)	0.0514 (9)	0.0162 (6)	0.0164 (7)	0.0049 (7)

Geometric parameters (Å, º)

Co1—O2	2.0763 (14)	C3—C4	1.389 (3)
Co1—O2^i	2.0763 (14)	C3—C5	1.507 (3)
Co1—O1W	2.0854 (19)	C4—H4A	0.9300
Co1—O1W^i	2.0854 (19)	C5—H5A	0.9600
Co1—N1	2.1176 (16)	C5—H5B	0.9600
Co1—N1^i	2.1176 (16)	C5—H5C	0.9600
N1—C1	1.335 (3)	C2—H2A	0.9300
N1—C4	1.335 (2)	O2—C6	1.271 (2)
C1—C2	1.379 (3)	O1—C6	1.229 (2)
C1—C6	1.519 (2)	O1W—H1WA	0.79 (3)
N2—C3	1.325 (3)	O1W—H1WB	0.76 (3)
N2—C2	1.340 (3)
O2—Co1—O2^i	180.00 (7)	N2—C3—C4	121.44 (18)
O2—Co1—O1W	90.19 (6)	N2—C3—C5	118.1 (2)
O2^i—Co1—O1W	89.81 (6)	C4—C3—C5	120.5 (2)
O2—Co1—O1W^i	89.81 (6)	N1—C4—C3	121.27 (19)
O2^i—Co1—O1W^i	90.19 (6)	N1—C4—H4A	119.4
O1W—Co1—O1W^i	180.00 (8)	C3—C4—H4A	119.4
O2—Co1—N1	78.97 (6)	C3—C5—H5A	109.5
O2^i—Co1—N1	101.03 (6)	C3—C5—H5B	109.5
O1W—Co1—N1	91.70 (8)	H5A—C5—H5B	109.5
O1W^i—Co1—N1	88.30 (8)	C3—C5—H5C	109.5
O2—Co1—N1^i	101.03 (6)	H5A—C5—H5C	109.5
O2^i—Co1—N1^i	78.97 (6)	H5B—C5—H5C	109.5
O1W—Co1—N1^i	88.30 (8)	N2—C2—C1	122.3 (2)
O1W^i—Co1—N1^i	91.70 (8)	N2—C2—H2A	118.9
N1—Co1—N1^i	180.000 (1)	C1—C2—H2A	118.9
C1—N1—C4	117.60 (16)	C6—O2—Co1	116.58 (11)
C1—N1—Co1	112.11 (12)	O1—C6—O2	126.44 (17)
C4—N1—Co1	130.29 (14)	O1—C6—C1	117.97 (17)
N1—C1—C2	120.57 (17)	O2—C6—C1	115.57 (16)
N1—C1—C6	116.66 (16)	Co1—O1W—H1WA	122.1 (19)
C2—C1—C6	122.74 (18)	Co1—O1W—H1WB	119 (2)
C3—N2—C2	116.84 (18)	H1WA—O1W—H1WB	110 (3)

Symmetry code: (i) −x, −y+1, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1W—H1WA···O2^ii	0.79 (3)	1.98 (3)	2.727 (2)	156.45
O1W—H1WB···O1^iii	0.76 (3)	1.94 (3)	2.675 (3)	164.62

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