trans-Diaqua­bis(5-methyl­pyrazine-2-carboxyl­ato-κ²O,N)zinc(II)

The crystal structure of the title compound, [Zn(C₆H₅N₂O₂)₂(H₂O)₂], consists of discrete mononuclear complex mol­ecules. The Zn^II ion is located on an inversion centre and is coordinated in a trans mode by the N,O-bonding groups donated by two 3-methyl­pyrazine-2-carboxyl­ate ligands [Zn—N = 2.109 (1) Å and Zn—O = 2.090 (1) Å] and by two aqua O atoms [Zn—O = 2.129 (2) Å]. The coordination geometry around the Zn^II ion is slightly distorted octa­hedral. The crystal structure is stabilized by a network of O—H...O hydrogen bonds operating between the coordinated water mol­ecules and carboxyl­ate O atoms.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.031
• wR factor = 0.085
• Data-to-parameter ratio = 16.1

checkCIF/PLATON results

No syntax errors found



Alert level C
CELLV02_ALERT_1_C  The supplied cell volume s.u. differs from that
            calculated from the cell parameter s.u.'s by > 2
            Calculated cell volume su =      15.33
            Cell volume su given      =      13.00
PLAT152_ALERT_1_C Supplied and Calc Volume s.u. Inconsistent .....          ?
PLAT154_ALERT_1_C The su's on the Cell Angles are Equal (x 10000)        3000 Deg.
PLAT164_ALERT_4_C Nr. of Refined C-H H-Atoms in Heavy-At Struct...          5
PLAT222_ALERT_3_C Large Non-Solvent    H     Ueq(max)/Ueq(min) ...       3.12 Ratio
PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor ....       2.51
PLAT390_ALERT_3_C Deviating Methyl C8      X-C-H Bond Angle ......     119.00 Deg.

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

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

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

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Computing details

Data collection: KM-4 Software (Kuma Diffraction, 1996); cell refinement: KM-4 Software; data reduction: DATAPROC (Kuma, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP (Siemens, 1992); software used to prepare material for publication: SHELXL97.

trans-Diaquabis(5-methylpyrazine-2-carboxylato-κ²O,N)zinc(II)

Crystal data

[Zn(C6H5N2O2)2(H2O)2]	Z = 1
Mr = 375.64	F(000) = 192
Triclinic, P1	Dx = 1.700 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 5.1405 (10) Å	Cell parameters from 25 reflections
b = 6.4312 (13) Å	θ = 6–15°
c = 12.234 (2) Å	µ = 1.71 mm^−1
α = 104.67 (3)°	T = 293 K
β = 90.61 (3)°	Block, colourless
γ = 109.44 (3)°	0.48 × 0.12 × 0.10 mm
V = 366.97 (13) Å^3

Data collection

Kuma KM-4 four-circle diffractometer	2070 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.010
Graphite monochromator	θmax = 30.1°, θmin = 1.7°
profile data from ω/2θ scans	h = −7→0
Absorption correction: analytical (CrysAlis RED; Oxford Diffraction, 2002)	k = −8→8
Tmin = 0.758, Tmax = 0.813	l = −17→17
2381 measured reflections	3 standard reflections every 200 reflections
2157 independent reflections	intensity decay: 0.2%

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)] = 0.031	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.085	All H-atom parameters refined
S = 1.10	w = 1/[σ^2(Fo^2) + (0.0602P)^2 + 0.0776P] where P = (Fo^2 + 2Fc^2)/3
2157 reflections	(Δ/σ)max < 0.001
134 parameters	Δρmax = 0.95 e Å^−3
0 restraints	Δρmin = −0.80 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
Zn1	1.0000	0.5000	0.5000	0.02643 (10)
O3	0.6250 (3)	0.2195 (2)	0.43477 (13)	0.0368 (3)
N1	0.9066 (3)	0.5259 (2)	0.66926 (11)	0.0260 (2)
C6	0.7803 (3)	0.6550 (3)	0.73378 (14)	0.0311 (3)
C2	0.9956 (3)	0.3908 (2)	0.71483 (12)	0.0259 (3)
N2	0.8257 (4)	0.5138 (3)	0.89118 (13)	0.0444 (4)
C5	0.7419 (3)	0.6504 (3)	0.84581 (14)	0.0339 (3)
O2	1.2442 (3)	0.1366 (2)	0.68439 (12)	0.0394 (3)
C7	1.1528 (3)	0.2558 (2)	0.64163 (13)	0.0263 (3)
C3	0.9523 (4)	0.3848 (4)	0.82537 (15)	0.0404 (4)
O1	1.1819 (2)	0.28119 (19)	0.54285 (10)	0.0298 (2)
C8	0.6085 (5)	0.8018 (4)	0.9189 (2)	0.0498 (5)
H6	0.713 (5)	0.750 (4)	0.705 (2)	0.033 (5)*
H3	1.032 (5)	0.296 (4)	0.855 (2)	0.045 (7)*
H83	0.717 (10)	0.931 (8)	0.968 (4)	0.103 (15)*
H81	0.506 (8)	0.857 (7)	0.874 (4)	0.081 (11)*
H31	0.644 (6)	0.106 (6)	0.411 (3)	0.056 (8)*
H82	0.493 (8)	0.717 (6)	0.956 (3)	0.072 (10)*
H32	0.491 (5)	0.207 (4)	0.465 (2)	0.035 (6)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Zn1	0.03042 (14)	0.03387 (14)	0.02527 (13)	0.02101 (10)	0.01360 (9)	0.01205 (9)
O3	0.0298 (6)	0.0339 (6)	0.0509 (7)	0.0176 (5)	0.0168 (5)	0.0094 (5)
N1	0.0271 (5)	0.0319 (5)	0.0264 (5)	0.0177 (4)	0.0115 (4)	0.0102 (4)
C6	0.0331 (7)	0.0373 (7)	0.0316 (7)	0.0227 (6)	0.0123 (5)	0.0099 (6)
C2	0.0261 (6)	0.0307 (6)	0.0269 (6)	0.0159 (5)	0.0099 (5)	0.0095 (5)
N2	0.0534 (9)	0.0654 (10)	0.0289 (6)	0.0360 (8)	0.0181 (6)	0.0164 (7)
C5	0.0313 (7)	0.0430 (8)	0.0298 (7)	0.0193 (6)	0.0122 (5)	0.0051 (6)
O2	0.0517 (7)	0.0423 (6)	0.0390 (6)	0.0329 (6)	0.0092 (5)	0.0138 (5)
C7	0.0251 (6)	0.0266 (6)	0.0313 (6)	0.0147 (5)	0.0083 (5)	0.0072 (5)
C3	0.0526 (10)	0.0548 (10)	0.0316 (8)	0.0345 (8)	0.0160 (7)	0.0202 (7)
O1	0.0324 (5)	0.0352 (5)	0.0324 (5)	0.0229 (4)	0.0144 (4)	0.0118 (4)
C8	0.0505 (11)	0.0596 (12)	0.0433 (10)	0.0324 (10)	0.0221 (8)	0.0023 (9)

Geometric parameters (Å, º)

Zn1—O1^i	2.0901 (12)	C2—C3	1.381 (2)
Zn1—O1	2.0901 (12)	C2—C7	1.516 (2)
Zn1—N1	2.1085 (13)	N2—C5	1.326 (3)
Zn1—N1^i	2.1085 (13)	N2—C3	1.339 (2)
Zn1—O3	2.1287 (16)	C5—C8	1.495 (2)
Zn1—O3^i	2.1287 (16)	O2—C7	1.2331 (19)
O3—H31	0.75 (4)	C7—O1	1.2637 (19)
O3—H32	0.77 (3)	C3—H3	0.94 (3)
N1—C6	1.3312 (18)	C8—H83	0.89 (5)
N1—C2	1.3342 (19)	C8—H81	0.96 (4)
C6—C5	1.393 (2)	C8—H82	0.88 (4)
C6—H6	0.93 (2)
O1^i—Zn1—O1	180	N1—C6—H6	120.5 (15)
O1^i—Zn1—N1	100.77 (5)	C5—C6—H6	118.3 (15)
O1—Zn1—N1	79.23 (5)	N1—C2—C3	120.13 (14)
O1^i—Zn1—N1^i	79.23 (5)	N1—C2—C7	116.92 (13)
O1—Zn1—N1^i	100.77 (5)	C3—C2—C7	122.90 (14)
N1—Zn1—N1^i	180	C5—N2—C3	117.08 (15)
O1^i—Zn1—O3	89.36 (5)	N2—C5—C6	121.05 (15)
O1—Zn1—O3	90.64 (5)	N2—C5—C8	118.08 (17)
N1—Zn1—O3	92.44 (6)	C6—C5—C8	120.87 (18)
N1^i—Zn1—O3	87.56 (6)	O2—C7—O1	126.43 (14)
O1^i—Zn1—O3^i	90.64 (5)	O2—C7—C2	117.39 (14)
O1—Zn1—O3^i	89.36 (5)	O1—C7—C2	116.16 (12)
N1—Zn1—O3^i	87.56 (6)	N2—C3—C2	122.39 (16)
N1^i—Zn1—O3^i	92.44 (6)	N2—C3—H3	121.0 (17)
O3—Zn1—O3^i	180	C2—C3—H3	116.3 (17)
Zn1—O3—H31	115 (2)	C7—O1—Zn1	115.69 (9)
Zn1—O3—H32	121.6 (18)	C5—C8—H83	119 (3)
H31—O3—H32	112 (3)	C5—C8—H81	112 (3)
C6—N1—C2	118.09 (13)	H83—C8—H81	103 (4)
C6—N1—Zn1	129.97 (11)	C5—C8—H82	107 (2)
C2—N1—Zn1	111.94 (10)	H83—C8—H82	109 (4)
N1—C6—C5	121.24 (15)	H81—C8—H82	108 (3)

Symmetry code: (i) −x+2, −y+1, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O3—H31···O2^ii	0.75 (4)	1.96 (4)	2.679 (2)	162 (3)
O3—H32···O1^iii	0.77 (3)	1.99 (3)	2.7374 (18)	161 (3)

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