Bis(pyrazine-2-carboxyl­ato-κ²N¹,O²)nickel(II) dihydrate

In the title compound, [Ni(C₅H₃N₂O₂)₂]·2H₂O, the Ni^II cation is four-coordinated by two N and two O atoms belonging to two pyrazine-2-carboxyl­ate ligands. The Ni^II atom occupies a special position at a centre of symmetry. Hydrogen bonds between water mol­ecules, and between water mol­ecules and carboxyl­ate O atoms, stabilize the crystal structure.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.005 Å
• R factor = 0.039
• wR factor = 0.096
• Data-to-parameter ratio = 11.7

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT230_ALERT_2_B Hirshfeld Test Diff for    N2     -   C3      ..       8.97 su
PLAT432_ALERT_2_B Short Inter X...Y Contact  C1     ..  C1      ..       3.04 Ang.

Alert level C
PLAT154_ALERT_1_C The su's on the Cell Angles are Equal  (x 10000)        200 Deg.
PLAT230_ALERT_2_C Hirshfeld Test Diff for    N2     -   C4      ..       5.92 su
PLAT232_ALERT_2_C Hirshfeld Test Diff (M-X)  Ni1    -   O1      ..       8.28 su
PLAT232_ALERT_2_C Hirshfeld Test Diff (M-X)  Ni1    -   N1      ..       5.66 su
PLAT241_ALERT_2_C Check High      Ueq as Compared to Neighbors for         N2
PLAT309_ALERT_2_C Single Bonded Oxygen (C-O .GT. 1.3 Ang) ........         O2
PLAT432_ALERT_2_C Short Inter X...Y Contact  O1     ..  C1      ..       2.96 Ang.

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 Ni1         (2)       1.65
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          3

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

   3 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   8 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

In recent years carboxylic acids have been widely used as polydentate ligands, which can coordinate to transition or rare earth ions yielding complexes with interesting properties that are useful in materials science (Church & Halvorson, 1959; Chung et al., 1971) and in biological systems (Okabe & Oya, 2000; Serre et al., 2005; Pocker & Fong, 1980; Scapin et al., 1997). Herein, we report the synthesis and X-ray crystal structure analysis of the title compound bis(pyrazine-2-carboxylato)nickel(II) hydrate (Fig. 1). The nickel cation is tetra-coordinated by two O an d two N atoms belonging to two pyrazine-2-carboxylate. Hydrogen bonds between symmetry operated water molecules, and water molecule and carboxylate oxygen atom stablize the crystal structure (Table 1 and Fig. 2).

Related literature

For related literature, see: Church & Halvorson (1959); Chung et al. (1971); Okabe & Oya (2000); Serre et al. (2005); Pocker & Fong (1980); Scapin et al. (1997).

S2. Experimental

The 8 ml etanol solution of nickel acetate (0.5 mmol), pyrazine-2-carboxylic acid (1.0 mmol) in a 25 ml Teflon-lined stainless steel autoclave was kept at 423 K for three days. Green crystals were obtained after cooling to room temperature with a yield of 35%. Anal. Calc. for C₁₀H₁₀N₄Ni: C 35.19, H 2.93, N 16.42%; Found: C 35.11, H 2.97, N 16.38%.

S3. Refinement

The H atoms of the water molecule were located from difference density maps and were refined with distance restraints of d(H–H) = 1.38 (2)Å and d(O–H) = 0.82 (2) Å. All other H atoms were placed in calculated positions with a C—H bond distance of 0.93 Å and U_iso(H) = 1.2U_eq of the respective carrier atom.

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) with the 30% probability displacement ellipsoids. Symmetry operator i: 1 x, y, z + 1.
	Fig. 2. The packing diagram of the title compound along the direction [010].

Bis(pyrazine-2-carboxylato-κ²N¹,O²)nickel(II) dihydrate

Crystal data

[Ni(C5H3N2O2)2]·2H2O	Z = 1
Mr = 340.93	F(000) = 174
Triclinic, P1	Dx = 1.632 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 5.5576 (6) Å	Cell parameters from 1208 reflections
b = 7.3252 (9) Å	θ = 2.3–25.0°
c = 9.3021 (11) Å	µ = 1.43 mm^−1
α = 75.065 (2)°	T = 293 K
β = 84.298 (2)°	Cube, green
γ = 71.503 (2)°	0.10 × 0.10 × 0.10 mm
V = 346.93 (7) Å^3

Data collection

Bruker APEX II CCD area-detector diffractometer	1208 independent reflections
Radiation source: fine-focus sealed tube	1111 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.050
φ and ω scans	θmax = 25.0°, θmin = 2.3°
Absorption correction: multi-scan (SADABS; Bruker, 2001)	h = −6→5
Tmin = 0.870, Tmax = 0.870	k = −8→8
1705 measured reflections	l = −8→11

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)] = 0.039	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.096	H atoms treated by a mixture of independent and constrained refinement
S = 1.00	w = 1/[σ^2(Fo^2) + (0.0571P)^2] where P = (Fo^2 + 2Fc^2)/3
1208 reflections	(Δ/σ)max < 0.001
103 parameters	Δρmax = 0.54 e Å^−3
3 restraints	Δρmin = −0.51 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
Ni1	1.0000	0.0000	1.0000	0.0297 (2)
C1	0.4654 (6)	0.1781 (4)	1.0641 (4)	0.0332 (7)
C2	0.5285 (6)	0.3005 (4)	0.9152 (4)	0.0317 (7)
C3	0.3444 (6)	0.4682 (5)	0.8416 (4)	0.0385 (8)
H3	0.1797	0.5093	0.8789	0.046*
C4	0.6886 (8)	0.4949 (5)	0.6507 (4)	0.0481 (9)
H4	0.7394	0.5640	0.5604	0.058*
C5	0.8593 (7)	0.3250 (5)	0.7289 (4)	0.0412 (8)
H5	1.0228	0.2770	0.6919	0.049*
N1	0.7810 (5)	0.2302 (4)	0.8615 (3)	0.0326 (6)
N2	0.4262 (7)	0.5699 (5)	0.7071 (4)	0.0652 (10)
O1	0.6702 (4)	0.0410 (3)	1.1256 (2)	0.0378 (5)
O2	0.2286 (4)	0.2137 (3)	1.1166 (3)	0.0455 (6)
O1W	0.2352 (8)	0.0433 (7)	0.4397 (4)	0.1007 (13)
H1W	0.212 (13)	0.087 (10)	0.347 (3)	0.151*
H2W	0.369 (8)	−0.051 (8)	0.455 (7)	0.151*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ni1	0.0229 (3)	0.0247 (3)	0.0327 (3)	−0.0004 (2)	0.0048 (2)	−0.0021 (2)
C1	0.0315 (17)	0.0276 (15)	0.0401 (18)	−0.0068 (13)	0.0029 (13)	−0.0115 (13)
C2	0.0307 (16)	0.0260 (15)	0.0393 (18)	−0.0074 (13)	0.0009 (13)	−0.0114 (13)
C3	0.0374 (18)	0.0293 (16)	0.0450 (19)	−0.0040 (14)	−0.0017 (14)	−0.0100 (14)
C4	0.061 (2)	0.0363 (18)	0.041 (2)	−0.0155 (17)	−0.0010 (17)	0.0021 (15)
C5	0.0383 (18)	0.0409 (18)	0.0406 (19)	−0.0125 (15)	0.0048 (15)	−0.0046 (15)
N1	0.0315 (14)	0.0272 (13)	0.0365 (15)	−0.0072 (11)	0.0026 (11)	−0.0065 (11)
N2	0.074 (3)	0.0471 (19)	0.067 (2)	−0.0094 (17)	−0.0119 (19)	−0.0083 (17)
O1	0.0340 (12)	0.0307 (11)	0.0390 (13)	−0.0014 (9)	0.0043 (10)	−0.0043 (10)
O2	0.0343 (13)	0.0406 (13)	0.0530 (15)	−0.0033 (10)	0.0137 (11)	−0.0121 (11)
O1W	0.106 (3)	0.127 (4)	0.059 (2)	−0.051 (3)	−0.002 (2)	0.014 (2)

Geometric parameters (Å, º)

Ni1—N1	1.968 (3)	C3—N2	1.395 (5)
Ni1—N1^i	1.968 (3)	C3—H3	0.9300
Ni1—O1^i	2.054 (2)	C4—C5	1.378 (5)
Ni1—O1	2.054 (2)	C4—N2	1.481 (5)
C1—O1	1.319 (4)	C4—H4	0.9300
C1—O2	1.326 (4)	C5—N1	1.355 (4)
C1—C2	1.519 (4)	C5—H5	0.9300
C2—C3	1.390 (5)	O1W—H1W	0.84 (2)
C2—N1	1.421 (4)	O1W—H2W	0.83 (5)
N1—Ni1—N1^i	180.00 (14)	N2—C3—H3	122.6
N1—Ni1—O1^i	99.06 (9)	C5—C4—N2	121.5 (3)
N1^i—Ni1—O1^i	80.94 (9)	C5—C4—H4	119.3
N1—Ni1—O1	80.94 (9)	N2—C4—H4	119.3
N1^i—Ni1—O1	99.06 (9)	N1—C5—C4	117.8 (3)
O1^i—Ni1—O1	180.0	N1—C5—H5	121.1
O1—C1—O2	127.9 (3)	C4—C5—H5	121.1
O1—C1—C2	111.3 (2)	C5—N1—C2	120.9 (3)
O2—C1—C2	120.8 (3)	C5—N1—Ni1	124.8 (2)
C3—C2—N1	124.7 (3)	C2—N1—Ni1	114.3 (2)
C3—C2—C1	120.0 (3)	C3—N2—C4	120.5 (3)
N1—C2—C1	115.3 (3)	C1—O1—Ni1	117.65 (19)
C2—C3—N2	114.7 (3)	H1W—O1W—H2W	110 (3)
C2—C3—H3	122.6

Symmetry code: (i) −x+2, −y, −z+2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1W—H2W···O1W^ii	0.83 (5)	2.52 (6)	3.071 (9)	125 (6)
O1W—H1W···O2^iii	0.84 (2)	2.11 (3)	2.941 (4)	167 (7)

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