Retracted: catena-Poly[[aqua­(pyrazine-2-carboxyl­ato)copper(II)]-μ-pyrazine-2-carboxyl­ato]

The title compound, [Cu(C₅H₃N₂O₂)₂(H₂O)]_n, prepared by hydro­thermal synthesis, is isostructural with its Fe^II-, Co^II- and Ni^II-containing analogues. The asymmetric unit contains two bidendate pyrazine-2-carboxyl­ate (pc) anions bonded to Cu in the equatorial plane through one N and one O atom. The Cu atoms are linked into chains by the second N atom of one of the pc anions bonding to an axial site of a neighbouring Cu atom. The slightly distorted octa­hedral coordination around Cu is completed by a water mol­ecule, which forms hydrogen bonds to link the chains into a three-dimensional structure. The crystal studied was an inversion twin.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.006 Å
• R factor = 0.038
• wR factor = 0.099
• Data-to-parameter ratio = 13.5

checkCIF/PLATON results

No syntax errors found



Alert level C
STRVA01_ALERT_4_C           Flack test results are ambiguous.
           From the CIF: _refine_ls_abs_structure_Flack    0.490
           From the CIF: _refine_ls_abs_structure_Flack_su    0.020
PLAT033_ALERT_2_C Flack Parameter Value Deviates 2 * su from zero.       0.49
PLAT094_ALERT_2_C Ratio of Maximum / Minimum Residual Density ....       3.34
PLAT222_ALERT_3_C Large Non-Solvent    H     Ueq(max)/Ueq(min) ...       3.08 Ratio
PLAT710_ALERT_4_C Delete 1-2-3 or 2-3-4 Linear Torsion Angle ... #         51
            O3  -CU1 -O1  -C1   -133.60  1.60   1.555   1.555   1.555   1.555
PLAT710_ALERT_4_C Delete 1-2-3 or 2-3-4 Linear Torsion Angle ... #         58
            O1  -CU1 -O3  -C6    -38.50  1.80   1.555   1.555   1.555   1.555

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           26.99
           From the CIF: _reflns_number_total               2460
           Count of symmetry unique reflns         1459
           Completeness (_total/calc)            168.61%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured      1001
           Fraction of Friedel pairs measured     0.686
           Are heavy atom types Z>Si present        yes
PLAT794_ALERT_5_G Check Predicted Bond Valency for Cu1         (2)       2.29
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
   6 ALERT level C = Check and explain
   3 ALERT level G = General alerts; check

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

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S1. Comment

The title compound, (I), is isostructural with its Fe^II, Co^II, and Ni^II analogues [Hao & Liu, (2007); Hao, Mu & Liu, (2007); Gao et al. (2007)]. The Cu^II atom in (I) is coordinated in a bidentate fashion by two O and two N atoms from two independent pyrazine-2-carboxylate anions. The distorted octhedral coordiantion is completed by another N atom from a third pyrazine-2-carboxylate ligand, and by the O atom of a water molecule (Fig. 1, Table 1). One pyrazine-2-carboxylate ligand coordinates to a neighboring Cu atom via its second N atom, leading to a polymeic structure with zigzag chains extending parallel to the b axis (Fig. 2). Hydrogen bonding involving the water molecules (Table 2) stablizes the structure.

Related literature

For the isostructural Fe^II, Co^II, and Ni^II analogues, see: Hao & Liu (2007); Hao et al. (2007); Gao et al. (2007).

[Prep section states red block crystals were formed, but CIF data tables state blue cube - which is correct?]

S2. Experimental

A mixture of copper dichloride hexahydrate (0.5 mmol), potassium hydroxide (0.5 mmol), 2-pyrazine caboxylic acid (0.5 mmol), EtOH (8 ml) and H₂O (8 ml) in a 25 ml Teflon-lined stainless steel autoclave was heated to at 413 K for 2 d, and then cooled to room temperature. Red block-shaped crystals of (I) were obtained in a yield of 36%. Anal. Calc. for C₁₀H₈CuN₄O₅: C 36.62, H 2.44, N 17.09%; Found: C 36.59, H 2.47, N 17.01%.

S3. Refinement

All H atoms on C atoms were generated geometrically (C—H = 0.93 Å) and refined as riding with U_iso(H) = 1.2U_eq(C). The H atoms of the water molecule were located from difference density maps and were refined with distance restraints of O—H = 0.82 (1) Å and H···H = 1.38 (2) Å and a fixed U_iso(H) of 0.08 Ų.

Computing details

Data collection: SMART (Bruker, 2001) [Or APEX2?]; cell refinement: SAINT-Plus (Bruker, 2001); data reduction: SAINT-Plus; 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.

Figures

Fig. 1. A fragment of the structure of (I) showing 30% probability displacement ellipsoids (arbitrary spheres for the H atoms). Atoms labeled with I at the symmetry positions (-x + 1, y - 1/2, -z + 3/2).

catena-Poly[[aqua(pyrazine-2-carboxylato)copper(II)]-µ-pyrazine-2-carboxylato]

Crystal data

[Cu(C5H3N2O2)2(H2O)]	F(000) = 660
Mr = 327.74	Dx = 1.894 Mg m^−3
Orthorhombic, P212121	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2ab	Cell parameters from 2460 reflections
a = 7.7379 (5) Å	θ = 2.5–27.0°
b = 9.9021 (5) Å	µ = 1.93 mm^−1
c = 15.002 (1) Å	T = 298 K
V = 1149.48 (12) Å^3	Cube, blue
Z = 4	0.10 × 0.10 × 0.10 mm

Data collection

Bruker APEXII CCD area-detector diffractometer	2219 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.032
Graphite monochromator	θmax = 27.0°, θmin = 2.5°
φ and ω scans	h = −8→9
6840 measured reflections	k = −12→12
2460 independent reflections	l = −15→19

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)] = 0.038	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.099	w = 1/[σ^2(Fo^2) + (0.0666P)^2 + 0.3756P] where P = (Fo^2 + 2Fc^2)/3
S = 1.01	(Δ/σ)max = 0.014
2460 reflections	Δρmax = 1.20 e Å^−3
182 parameters	Δρmin = −0.36 e Å^−3
3 restraints	Absolute structure: Flack (1983), with 1004 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.49 (2)

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
Cu1	0.42685 (6)	0.63422 (4)	0.59076 (3)	0.01911 (14)
C1	0.1940 (5)	0.8096 (4)	0.6830 (3)	0.0259 (5)
C2	0.3720 (5)	0.8540 (4)	0.7110 (2)	0.0174 (7)
C3	0.3948 (5)	0.9581 (4)	0.7733 (3)	0.0214 (8)
H3	0.2981	1.0026	0.7955	0.026*
C4	0.6843 (6)	0.9334 (4)	0.7638 (3)	0.0243 (9)
H4	0.7954	0.9589	0.7804	0.029*
C5	0.6628 (5)	0.8307 (4)	0.6996 (3)	0.0226 (9)
H5	0.7594	0.7905	0.6740	0.027*
C6	0.6424 (6)	0.4713 (4)	0.4810 (3)	0.0228 (9)
C7	0.4616 (5)	0.4269 (4)	0.4590 (3)	0.0232 (9)
C8	0.4259 (6)	0.3353 (4)	0.3918 (3)	0.0323 (10)
H8	0.5175	0.2988	0.3597	0.039*
C9	0.1408 (6)	0.3514 (4)	0.4213 (3)	0.0307 (9)
H9	0.0268	0.3269	0.4101	0.037*
C10	0.1755 (6)	0.4432 (4)	0.4894 (3)	0.0271 (9)
H10	0.0847	0.4779	0.5230	0.033*
N1	0.5062 (4)	0.7910 (3)	0.6756 (2)	0.0195 (7)
N2	0.5494 (4)	0.9948 (3)	0.8012 (2)	0.0191 (7)
N3	0.3352 (4)	0.4817 (3)	0.5070 (2)	0.0197 (7)
N4	0.2667 (5)	0.2974 (4)	0.3713 (3)	0.0383 (10)
O1	0.1945 (3)	0.7028 (3)	0.63112 (18)	0.0201 (6)
O2	0.0686 (3)	0.8697 (3)	0.70894 (18)	0.0259 (5)
O3	0.6530 (4)	0.5644 (3)	0.54124 (19)	0.0218 (6)
O4	0.7633 (4)	0.4208 (4)	0.4411 (3)	0.0434 (9)
O5	0.4184 (4)	0.7653 (3)	0.48314 (19)	0.0274 (6)
H1W	0.509 (5)	0.793 (6)	0.462 (5)	0.080*
H2W	0.335 (5)	0.815 (6)	0.475 (5)	0.080*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cu1	0.0166 (2)	0.0202 (2)	0.0205 (2)	−0.00007 (19)	−0.00077 (19)	−0.00039 (19)
C1	0.0155 (10)	0.0306 (12)	0.0314 (12)	0.0031 (11)	−0.0021 (9)	−0.0043 (10)
C2	0.0168 (17)	0.0186 (17)	0.0168 (17)	0.0012 (14)	−0.0034 (13)	0.0012 (15)
C3	0.021 (2)	0.0237 (18)	0.0189 (18)	0.0014 (15)	0.0012 (16)	−0.0043 (15)
C4	0.019 (2)	0.0229 (19)	0.031 (2)	−0.0010 (17)	−0.0004 (17)	−0.0052 (17)
C5	0.0156 (19)	0.024 (2)	0.029 (2)	0.0018 (16)	0.0015 (16)	−0.0003 (16)
C6	0.0189 (19)	0.024 (2)	0.025 (2)	−0.0033 (16)	0.0005 (16)	0.0005 (16)
C7	0.024 (2)	0.0222 (19)	0.023 (2)	0.0035 (16)	0.0005 (16)	0.0005 (16)
C8	0.023 (2)	0.037 (2)	0.038 (3)	0.003 (2)	0.002 (2)	−0.0162 (17)
C9	0.0215 (19)	0.033 (2)	0.038 (2)	−0.0013 (18)	−0.0046 (18)	−0.007 (2)
C10	0.022 (2)	0.027 (2)	0.032 (2)	0.0010 (17)	0.0026 (18)	−0.0019 (17)
N1	0.0169 (15)	0.0205 (16)	0.0211 (17)	0.0013 (13)	−0.0001 (13)	0.0009 (13)
N2	0.0184 (17)	0.0182 (14)	0.0206 (15)	0.0002 (14)	0.0006 (13)	−0.0037 (12)
N3	0.0185 (16)	0.0182 (16)	0.0223 (16)	0.0007 (13)	−0.0003 (14)	−0.0014 (13)
N4	0.031 (2)	0.041 (2)	0.043 (2)	−0.0074 (18)	−0.0033 (18)	−0.0200 (19)
O1	0.0146 (13)	0.0238 (13)	0.0219 (14)	0.0003 (11)	−0.0022 (11)	−0.0039 (11)
O2	0.0155 (10)	0.0306 (12)	0.0314 (12)	0.0031 (11)	−0.0021 (9)	−0.0043 (10)
O3	0.0135 (13)	0.0233 (14)	0.0286 (15)	−0.0016 (11)	0.0001 (11)	−0.0007 (12)
O4	0.0217 (17)	0.054 (2)	0.054 (2)	0.0074 (16)	0.0067 (15)	−0.0191 (17)
O5	0.0234 (15)	0.0304 (15)	0.0285 (14)	0.0089 (15)	0.0052 (14)	0.0127 (12)

Geometric parameters (Å, º)

Cu1—O1	2.015 (3)	C5—H5	0.9300
Cu1—O3	2.023 (3)	C6—O4	1.218 (5)
Cu1—O5	2.073 (3)	C6—O3	1.293 (5)
Cu1—N3	2.089 (3)	C6—C7	1.503 (6)
Cu1—N1	2.099 (3)	C7—N3	1.331 (5)
Cu1—N2^i	2.137 (3)	C7—C8	1.384 (6)
C1—O2	1.203 (5)	C8—N4	1.324 (6)
C1—O1	1.313 (5)	C8—H8	0.9300
C1—C2	1.506 (5)	C9—N4	1.341 (6)
C2—N1	1.323 (5)	C9—C10	1.394 (6)
C2—C3	1.402 (5)	C9—H9	0.9300
C3—N2	1.319 (5)	C10—N3	1.320 (6)
C3—H3	0.9300	C10—H10	0.9300
C4—N2	1.332 (5)	N2—Cu1^ii	2.137 (3)
C4—C5	1.410 (6)	O5—H1W	0.82 (5)
C4—H4	0.9300	O5—H2W	0.82 (5)
C5—N1	1.324 (5)
O1—Cu1—O3	175.85 (12)	O4—C6—O3	126.0 (4)
O1—Cu1—O5	89.69 (12)	O4—C6—C7	119.1 (4)
O3—Cu1—O5	87.45 (12)	O3—C6—C7	114.9 (3)
O1—Cu1—N3	96.98 (12)	N3—C7—C8	121.0 (4)
O3—Cu1—N3	79.95 (12)	N3—C7—C6	116.5 (3)
O5—Cu1—N3	88.47 (13)	C8—C7—C6	122.6 (4)
O1—Cu1—N1	80.18 (12)	N4—C8—C7	122.8 (4)
O3—Cu1—N1	102.86 (13)	N4—C8—H8	118.6
O5—Cu1—N1	91.06 (13)	C7—C8—H8	118.6
N3—Cu1—N1	177.12 (14)	N4—C9—C10	122.0 (4)
O1—Cu1—N2^i	93.83 (12)	N4—C9—H9	119.0
O3—Cu1—N2^i	89.04 (12)	C10—C9—H9	119.0
O5—Cu1—N2^i	176.48 (14)	N3—C10—C9	121.0 (4)
N3—Cu1—N2^i	91.07 (13)	N3—C10—H10	119.5
N1—Cu1—N2^i	89.57 (12)	C9—C10—H10	119.5
O2—C1—O1	126.3 (4)	C2—N1—C5	118.0 (3)
O2—C1—C2	120.2 (4)	C2—N1—Cu1	111.3 (3)
O1—C1—C2	113.5 (3)	C5—N1—Cu1	130.7 (3)
N1—C2—C3	121.0 (3)	C3—N2—C4	116.8 (3)
N1—C2—C1	117.9 (3)	C3—N2—Cu1^ii	119.8 (3)
C3—C2—C1	121.1 (3)	C4—N2—Cu1^ii	123.2 (3)
N2—C3—C2	121.9 (4)	C10—N3—C7	117.5 (3)
N2—C3—H3	119.1	C10—N3—Cu1	130.3 (3)
C2—C3—H3	119.1	C7—N3—Cu1	111.8 (3)
N2—C4—C5	121.6 (4)	C9—N4—C8	115.7 (4)
N2—C4—H4	119.2	C1—O1—Cu1	116.9 (2)
C5—C4—H4	119.2	C6—O3—Cu1	116.5 (3)
N1—C5—C4	120.5 (4)	Cu1—O5—H1W	119 (5)
N1—C5—H5	119.8	Cu1—O5—H2W	121 (5)
C4—C5—H5	119.8	H1W—O5—H2W	114 (3)
O2—C1—C2—N1	−175.2 (4)	C5—C4—N2—Cu1^ii	172.6 (3)
O1—C1—C2—N1	5.7 (5)	C9—C10—N3—C7	−1.8 (6)
O2—C1—C2—C3	5.3 (6)	C9—C10—N3—Cu1	170.6 (3)
O1—C1—C2—C3	−173.8 (3)	C8—C7—N3—C10	1.5 (6)
N1—C2—C3—N2	−2.1 (6)	C6—C7—N3—C10	−179.4 (4)
C1—C2—C3—N2	177.3 (4)	C8—C7—N3—Cu1	−172.3 (3)
N2—C4—C5—N1	−1.0 (6)	C6—C7—N3—Cu1	6.8 (4)
O4—C6—C7—N3	177.6 (4)	O1—Cu1—N3—C10	−1.5 (4)
O3—C6—C7—N3	−3.8 (5)	O3—Cu1—N3—C10	−178.6 (4)
O4—C6—C7—C8	−3.3 (6)	O5—Cu1—N3—C10	−91.0 (4)
O3—C6—C7—C8	175.3 (4)	N2^i—Cu1—N3—C10	92.5 (4)
N3—C7—C8—N4	0.1 (7)	O1—Cu1—N3—C7	171.3 (3)
C6—C7—C8—N4	−179.0 (4)	O3—Cu1—N3—C7	−5.9 (2)
N4—C9—C10—N3	0.6 (7)	O5—Cu1—N3—C7	81.8 (3)
C3—C2—N1—C5	−1.1 (6)	N2^i—Cu1—N3—C7	−94.7 (3)
C1—C2—N1—C5	179.4 (4)	C10—C9—N4—C8	1.0 (7)
C3—C2—N1—Cu1	176.9 (3)	C7—C8—N4—C9	−1.3 (7)
C1—C2—N1—Cu1	−2.6 (4)	O2—C1—O1—Cu1	175.0 (4)
C4—C5—N1—C2	2.6 (6)	C2—C1—O1—Cu1	−6.0 (5)
C4—C5—N1—Cu1	−175.0 (3)	O3—Cu1—O1—C1	−133.6 (16)
O1—Cu1—N1—C2	−0.4 (2)	O5—Cu1—O1—C1	−87.4 (3)
O3—Cu1—N1—C2	176.7 (3)	N3—Cu1—O1—C1	−175.8 (3)
O5—Cu1—N1—C2	89.1 (3)	N1—Cu1—O1—C1	3.8 (3)
N2^i—Cu1—N1—C2	−94.4 (3)	N2^i—Cu1—O1—C1	92.7 (3)
O1—Cu1—N1—C5	177.3 (4)	O4—C6—O3—Cu1	177.0 (4)
O3—Cu1—N1—C5	−5.6 (4)	C7—C6—O3—Cu1	−1.6 (4)
O5—Cu1—N1—C5	−93.2 (4)	O1—Cu1—O3—C6	−38.5 (18)
N2^i—Cu1—N1—C5	83.3 (4)	O5—Cu1—O3—C6	−84.9 (3)
C2—C3—N2—C4	3.7 (6)	N3—Cu1—O3—C6	4.0 (3)
C2—C3—N2—Cu1^ii	−171.3 (3)	N1—Cu1—O3—C6	−175.4 (3)
C5—C4—N2—C3	−2.2 (6)	N2^i—Cu1—O3—C6	95.3 (3)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O5—H2W···O3^iii	0.82 (5)	1.86 (5)	2.682 (4)	177 (7)
O5—H1W···O1^iv	0.82 (5)	2.01 (4)	2.757 (4)	153 (7)

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