Diaqua­bis­(5-methyl-1,2-oxazole-3-car­box­yl­ato-κ²N,O³)cobalt(II) dihydrate

In the title compound, [Co(C₅H₄NO₃)₂(H₂O)₂]·2H₂O, the coordination polyhedron around the six-coordinate Co^II ion is formed by two equatorial 5-methyl­isoxazole-3-carboxyl­ate ligands in an N,O³-bidentate fashion through the isoxazole N atom and a carboxyl­ate O atom, and by two axial water ligands. The asymmetric unit consists of half of the complex and one water mol­ecule (the full comlex being completed by application of inversion). In the crystal, the water mol­ecules participate in the formation of an intricate three-dimensional network of hydrogen bonds involving the coordinated water mol­ecule and the carboxyl­ate groups.

Key indicators

• Single-crystal X-ray study
• T = 296 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.028
• wR factor = 0.078
• Data-to-parameter ratio = 10.9

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.595          2

Alert level G
PLAT005_ALERT_5_G No _iucr_refine_instructions_details in CIF ....          ?
PLAT128_ALERT_4_G Alternate Setting of Space-group P21/c   .......      P21/n
PLAT909_ALERT_3_G Percentage of Observed Data at Theta(Max) still          82 Perc.

   0 ALERT level A = Most likely a serious problem - resolve or explain
   0 ALERT level B = A potentially serious problem, consider carefully
   1 ALERT level C = Check. Ensure it is not caused by an omission or oversight
   3 ALERT level G = General information/check it is not something unexpected

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 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
   1 ALERT type 5 Informative message, check

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S1. Comment

Isoxazole derivatives are versatile ligands towards transition metal ions both in man-made and natural systems. They are not only used as (bio)catalysts but also for dioxygen transport and electron storage (Luo et al., 2011). As part of our interest in isoxazole derivatives, we report here the crystal structure of a new cobalt complex.

The molecular structure of the title compound is shown in Fig. 1. All non-H atoms, except O3 and O4, are located in the same plane with an r.m.s. deviation of 0.0247 Å.

The coordination polyhedron around the six coordinated central Co^II ion is described as a octahedron, formed by two equatorial 5-methylisoxazole-3-carboxylates in an O, N bidentate fashion through the isoxazole nitrogen and the carboxylate oxygen atoms and by two axial water ligands.

The title compound forms a three-dimensional structure via intermolecular O—H···O hydrogen bonds interactions (Table 1, Fig. 2).

Related literature

For a related structure, see: Luo et al. (2011).

S2. Experimental

0.06 g CoCl₂.6H₂O (mg) was added to a methanol solution of 0.06 g 5-methyl-3-isoxazolecarboxylic acid and stirred for three h at room temperature. The resulting solution was filtered off and allowed to evaporate at room temperature. Pillar pink crystals of the title compound were obtained within 3 days.

S3. Refinement

All H atoms attached to C atoms were fixed geometrically and treated as riding with C—H = 0.93 Å (CH), C—H = 0.96 Å (CH₃) with U_iso(H) = 1.2U_eq(CH) and U_iso(H) = 1.5U_eq(CH₃). H atoms of water molecules were located in difference Fourier maps and included in the subsequent refinement using restraints (O—H= 0.79 (1) Å with U_iso(H) = 1.5U_eq(O) or U_iso(H) = 2.0 U_eq(O). In the last cycles of refinement, they were treated as riding on their parent O atoms.

Computing details

Data collection: CrystalClear (Rigaku, 2005); cell refinement: CrystalClear (Rigaku, 2005); data reduction: CrystalClear (Rigaku, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg & Putz, 2005); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures

	Fig. 1. The molecular structure of the title compound with the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level. H atoms are represented as small spheres of arbitrary radii. Symmetry code: (A) -x+1, -y, -z+1.
	Fig. 2. A packing view down the a axis showing the three dimensional network. Intermolecular hydrogen bonds are shown as dashed lines.

Diaquabis(5-methyl-1,2-oxazole-3-carboxylato- κ²N,O³)cobalt(II) dihydrate

Crystal data

[Co(C5H4NO3)2(H2O)2]·2H2O	F(000) = 394
Mr = 383.18	Dx = 1.664 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 1344 reflections
a = 5.260 (3) Å	θ = 2.2–25.0°
b = 18.528 (10) Å	µ = 1.18 mm^−1
c = 8.077 (4) Å	T = 296 K
β = 103.707 (6)°	Pillar, pink
V = 764.9 (7) Å^3	0.20 × 0.20 × 0.20 mm
Z = 2

Data collection

Rigaku SCXmini diffractometer	1344 independent reflections
Radiation source: fine-focus sealed tube	1202 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.034
Detector resolution: 13.6612 pixels mm^-1	θmax = 25.0°, θmin = 2.2°
CCD_Profile_fitting scans	h = −6→6
Absorption correction: multi-scan (CrystalClear; Rigaku, 2005)	k = −22→22
Tmin = 0.983, Tmax = 0.983	l = −9→9
5217 measured reflections

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)] = 0.028	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.078	H atoms treated by a mixture of independent and constrained refinement
S = 1.06	w = 1/[σ^2(Fo^2) + (0.0428P)^2 + 0.2614P] where P = (Fo^2 + 2Fc^2)/3
1344 reflections	(Δ/σ)max < 0.001
123 parameters	Δρmax = 0.28 e Å^−3
0 restraints	Δρmin = −0.38 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
Co1	0.5000	0.0000	0.5000	0.02592 (16)
O1	0.8288 (3)	0.18878 (7)	0.38174 (19)	0.0361 (4)
O5	0.0881 (3)	0.06221 (8)	0.16193 (19)	0.0345 (4)
O2	0.7638 (3)	0.08451 (7)	0.50526 (17)	0.0293 (3)
N1	0.3171 (3)	0.06356 (9)	0.2896 (2)	0.0312 (4)
O3	0.3032 (4)	0.05798 (10)	0.6557 (2)	0.0369 (4)
C5	0.6992 (4)	0.13440 (10)	0.3955 (3)	0.0266 (4)
C4	0.4387 (4)	0.12311 (10)	0.2705 (3)	0.0270 (4)
C3	0.2957 (4)	0.16322 (12)	0.1325 (3)	0.0330 (5)
H3	0.3393	0.2077	0.0937	0.040*
C1	−0.1485 (5)	0.13125 (15)	−0.0775 (3)	0.0462 (6)
H1A	−0.1458	0.1782	−0.1275	0.069*
H1B	−0.3060	0.1259	−0.0382	0.069*
H1C	−0.1427	0.0949	−0.1612	0.069*
C2	0.0819 (4)	0.12328 (12)	0.0685 (3)	0.0313 (5)
O4	0.3191 (4)	0.20264 (10)	0.6234 (3)	0.0511 (5)
H3A	0.332 (6)	0.0981 (18)	0.655 (4)	0.051 (9)*
H3B	0.144 (8)	0.0564 (18)	0.623 (5)	0.081 (12)*
H4B	0.175 (8)	0.2028 (19)	0.555 (5)	0.080 (12)*
H4A	0.309 (7)	0.232 (2)	0.698 (5)	0.093 (13)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Co1	0.0265 (2)	0.0213 (2)	0.0275 (3)	−0.00130 (14)	0.00157 (17)	0.00343 (14)
O1	0.0380 (8)	0.0292 (8)	0.0374 (9)	−0.0093 (6)	0.0014 (7)	0.0050 (7)
O5	0.0321 (8)	0.0325 (8)	0.0324 (8)	−0.0032 (6)	−0.0051 (6)	0.0006 (6)
O2	0.0287 (7)	0.0267 (7)	0.0290 (8)	−0.0024 (6)	−0.0002 (6)	0.0046 (6)
N1	0.0300 (9)	0.0284 (9)	0.0301 (10)	−0.0019 (7)	−0.0030 (7)	0.0033 (7)
O3	0.0360 (10)	0.0318 (10)	0.0424 (10)	0.0002 (7)	0.0082 (7)	−0.0041 (7)
C5	0.0281 (10)	0.0244 (10)	0.0269 (11)	−0.0005 (8)	0.0059 (8)	−0.0007 (8)
C4	0.0297 (10)	0.0254 (10)	0.0252 (11)	−0.0006 (8)	0.0052 (8)	0.0007 (8)
C3	0.0374 (11)	0.0294 (11)	0.0305 (11)	0.0014 (9)	0.0048 (9)	0.0085 (9)
C1	0.0409 (13)	0.0579 (16)	0.0329 (13)	0.0074 (11)	−0.0051 (10)	0.0006 (11)
C2	0.0344 (11)	0.0343 (11)	0.0234 (11)	0.0064 (9)	0.0031 (9)	0.0012 (9)
O4	0.0483 (11)	0.0376 (10)	0.0598 (12)	0.0073 (8)	−0.0024 (9)	−0.0118 (9)

Geometric parameters (Å, º)

Co1—O2^i	2.0860 (16)	O3—H3B	0.82 (4)
Co1—O2	2.0860 (16)	C5—C4	1.512 (3)
Co1—N1^i	2.1035 (18)	C4—C3	1.401 (3)
Co1—N1	2.1035 (18)	C3—C2	1.343 (3)
Co1—O3^i	2.1038 (18)	C3—H3	0.9300
Co1—O3	2.1038 (18)	C1—C2	1.485 (3)
O1—C5	1.236 (2)	C1—H1A	0.9600
O5—C2	1.356 (3)	C1—H1B	0.9600
O5—N1	1.388 (2)	C1—H1C	0.9600
O2—C5	1.270 (2)	O4—H4B	0.83 (4)
N1—C4	1.303 (3)	O4—H4A	0.83 (5)
O3—H3A	0.76 (3)
O2^i—Co1—O2	180.00 (5)	Co1—O3—H3B	113 (3)
O2^i—Co1—N1^i	76.76 (6)	H3A—O3—H3B	103 (3)
O2—Co1—N1^i	103.24 (6)	O1—C5—O2	126.42 (19)
O2^i—Co1—N1	103.24 (6)	O1—C5—C4	119.00 (17)
O2—Co1—N1	76.76 (6)	O2—C5—C4	114.57 (16)
N1^i—Co1—N1	180.0	N1—C4—C3	110.96 (18)
O2^i—Co1—O3^i	91.37 (8)	N1—C4—C5	115.51 (17)
O2—Co1—O3^i	88.63 (8)	C3—C4—C5	133.53 (18)
N1^i—Co1—O3^i	90.08 (8)	C2—C3—C4	104.87 (19)
N1—Co1—O3^i	89.92 (8)	C2—C3—H3	127.6
O2^i—Co1—O3	88.63 (8)	C4—C3—H3	127.6
O2—Co1—O3	91.37 (8)	C2—C1—H1A	109.5
N1^i—Co1—O3	89.92 (8)	C2—C1—H1B	109.5
N1—Co1—O3	90.08 (8)	H1A—C1—H1B	109.5
O3^i—Co1—O3	180.00 (7)	C2—C1—H1C	109.5
C2—O5—N1	107.48 (15)	H1A—C1—H1C	109.5
C5—O2—Co1	117.73 (12)	H1B—C1—H1C	109.5
C4—N1—O5	106.92 (16)	C3—C2—O5	109.77 (18)
C4—N1—Co1	115.26 (13)	C3—C2—C1	134.6 (2)
O5—N1—Co1	137.76 (13)	O5—C2—C1	115.60 (19)
Co1—O3—H3A	112 (2)	H4B—O4—H4A	106 (3)

Symmetry code: (i) −x+1, −y, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O4—H4A···O1^ii	0.83 (5)	2.07 (5)	2.890 (3)	172 (4)
O4—H4B···O1^iii	0.83 (4)	2.03 (4)	2.853 (3)	172 (3)
O3—H3B···O2^iii	0.82 (4)	2.07 (4)	2.852 (3)	161 (3)
O3—H3A···O4	0.76 (3)	1.95 (3)	2.696 (3)	167 (3)

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