Bis(guanidinium) trans-diaqua­bis(malonato-κ²O,O′)cobaltate(II)

In the title compound, (CH₆N₃)₂[Co(C₃H₂O₄)₂(H₂O)₂], the anions lie on crystallographic centres of inversion. The crystal structure adopts a layered structure, stabilized by an extensive network of N—H...O and O—H...O hydrogen bonds. One H atom of the guanidinium cation does not participate in any strong hydrogen bonds.

Key indicators

• Single-crystal X-ray study
• T = 100 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.031
• wR factor = 0.091
• Data-to-parameter ratio = 30.0

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ ....          ?
PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor ....       2.10
PLAT420_ALERT_2_C D-H Without Acceptor       N20    -   H202   ...          ?

Alert level G
REFLT03_ALERT_1_G ALERT: Expected hkl max differ from CIF values
           From the CIF: _diffrn_reflns_theta_max           36.54
           From the CIF: _reflns_number_total               3445
           From the CIF: _diffrn_reflns_limit_ max hkl   14.   17.   13.
           From the CIF: _diffrn_reflns_limit_ min hkl  -14.  -15.  -13.
           TEST1: Expected hkl limits for theta max
           Calculated maximum hkl   15.   19.   13.
           Calculated minimum hkl  -15.  -19.  -13.

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

   2 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
   0 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

Supramolecular motifs with malonate ions have been widely explored in crystal engineering (Hemamalini et al., 2006, Zhao et al., 2007). These ligands as part of [M(malonate)₂(H₂O)₂]^2- anions have been used as "robust anionic building blocks for crystal engineering of inorganic-organic hybrid materials" (Zhao et al., 2007).

The title compound consists of trans-diaquabis(malonato-O,O')-cobaltate(II) anions and guanidinium cations (Fig. 1). In each centrosymmetric anion, the central Co^II atom is octahedrally surrounded by two water ligands and two chelating malonate ligands. The guanidinium cation geometrical parameters agree with those previously reported (Cygler et al., 1976).

The crystal adopts a layered structure, common for guanidinium salts (Fig. 2; Videnova-Adrabińska et al., 2007). Alternate layers consist of the trans-diaquabis(malonato-O,O')-cobaltate(II) anions and the guanidinium cations. Within each anion layer, both water ligands are involved in O—H···O hydrogen bonds. In two of these hydrogen bonds, the carboxyl O22 and O21 atoms from the malonate ligands act as acceptors (Fig. 3). Each guanidinium cation is hydrogen bonded to the anions from both neighbouring anion layers (Fig. 3). Atom H201 participates in a bifurcated N—H···O hydrogen bond to the malonate carboxyl O11 and water O1W atoms, constituting a R¹₂(4) motif (Etter et al., 1990). Atom H302 is involved in the N30—H302···O21 hydrogen bond with the malonate carboxyl O21 atom. This hydrogen bond along with the N20—H201···O11 hydrogen bonds forms a R²₂(8) motif (Etter et al., 1990). The hydrogen bonds formed between the guanidinium cation and another anion layer are the following: N10—H102···O21, N10—H101···O12 and N30—H301···O22. The latter two form a R³₁(8) structural motif (Etter et al., 1990). It is interesting to note that one guanidinium H atom (H202) is not involved in any strong hydrogen bonds.

Related literature

For related literature, see: Cygler et al. (1976); Etter et al. (1990); Hemamalini et al. (2006); Videnova-Adrabińska et al. (2007); Zhao et al. (2007).

S2. Experimental

The title complex was prepared by dissolving guanidinium carbonate (4 mmol, 720 mg) and malonic acid (2 mmol, 208 mg) in water (20 ml). The mixture was stirred for about 1 h at room temperature. Subsequently, Co(ClO₄)₂ (1 mmol, 366 mg) was added to the resulting solution and stirred for about 3 h at room temperature. The solution yielded crystals after 10 d.

S3. Refinement

The malonate H atoms were generated in their calculated positions. All remaining H atoms were found in difference Fourier maps and their positions were refined initially with the water O—H bond lengths and guanidinium N—H bond lengths restrained to be 0.820 (1) and 0.860 (1) Å, respectively. In the final stages of refinement, these H atoms were constrained to ride on their parent atoms (AFIX 3 instruction) with U_iso(H) = 1.2U_eq(parent atom).

Computing details

Data collection: CrysAlis CCD (Oxford Diffraction, 2006); cell refinement: CrysAlis RED (Oxford Diffraction, 2006); data reduction: CrysAlis RED (Oxford Diffraction, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg & Putz, 2005); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).

Figures

	Fig. 1. The molecular structure of the title compound with displacement ellipsoids at 30% probability for non-H atoms. The part indicated with dashed lines is generated by the symmetry operation -x + 1, -y + 1, -z + 1.
	Fig. 2. View of the crystal structure along [010] showing cation and anion layers parallel to the bc plane.
	Fig. 3. View of the hydrogen bonding scheme. The non-aqueous H atoms not participating in any hydrogen bonds have been omitted and the neighbouring ions have been denoted with different colour (gray and black). The hydrogen bonds are indicated with dashed lines. Symmetry operations: (i) -x + 1, -y + 1, -z + 1; (ii) -x + 2, y - 1/2, -z + 3/2; (iii) x + 1, y, z + 1; (iv) x, -y + 3/2, z + 1/2; (v) -x + 1, y - 1/2, -z + 3/2.

Bis(guanidinium) trans-diaquabis(malonato-κ²O,O')cobaltate(II)

Crystal data

(CH6N3)2[Co(C3H2O4)2(H2O)2]	F(000) = 434
Mr = 419.23	Dx = 1.752 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 9403 reflections
a = 8.969 (3) Å	θ = 2–35°
b = 11.524 (4) Å	µ = 1.15 mm^−1
c = 8.272 (3) Å	T = 100 K
β = 111.61 (4)°	Block, pink
V = 794.9 (5) Å^3	0.31 × 0.25 × 0.18 mm
Z = 2

Data collection

Oxford Diffraction XcaliburPX CCD diffractometer	3445 independent reflections
Radiation source: sealed tube	2768 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.024
ω & φ scans	θmax = 36.5°, θmin = 3.0°
Absorption correction: analytical (CrysAlis RED; Oxford Diffraction, 2006)	h = −14→14
Tmin = 0.720, Tmax = 0.848	k = −15→17
11133 measured reflections	l = −13→13

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) = 0.091	H-atom parameters constrained
S = 1.03	w = 1/[σ^2(Fo^2) + (0.060P)^2] where P = (Fo^2 + 2Fc^2)/3
3445 reflections	(Δ/σ)max < 0.001
115 parameters	Δρmax = 0.58 e Å^−3
0 restraints	Δρmin = −0.43 e Å^−3

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Co	0.5000	0.5000	0.5000	0.00962 (6)
O11	0.63731 (9)	0.63701 (7)	0.64141 (10)	0.01133 (14)
O21	0.73793 (9)	0.81502 (7)	0.69642 (10)	0.01402 (15)
O12	0.36319 (9)	0.61700 (7)	0.32127 (10)	0.01255 (15)
O22	0.26743 (9)	0.78487 (7)	0.19808 (10)	0.01408 (16)
N10	1.18921 (11)	0.52517 (9)	0.97198 (13)	0.01332 (17)
H101	1.2399	0.5498	1.0759	0.016*
H102	1.2123	0.4595	0.9380	0.016*
N20	0.96719 (12)	0.53173 (10)	0.71656 (13)	0.01675 (19)
H201	0.8722	0.5562	0.6569	0.020*
H202	0.9805	0.4605	0.6947	0.020*
N30	1.01516 (11)	0.68018 (9)	0.91834 (13)	0.01470 (17)
H301	1.0815	0.7133	1.0096	0.018*
H302	0.9314	0.7147	0.8478	0.018*
C2	0.49632 (12)	0.79769 (10)	0.45438 (14)	0.01213 (19)
H1	0.5473	0.8466	0.3909	0.015*
H2	0.4393	0.8512	0.5055	0.015*
O1W	0.33221 (11)	0.50357 (6)	0.62312 (12)	0.01377 (16)
H1W	0.3146	0.5620	0.6696	0.017*
H2W	0.3253	0.4567	0.6947	0.017*
C3	0.36771 (11)	0.72673 (9)	0.31750 (13)	0.00952 (17)
C10	1.05660 (12)	0.57952 (10)	0.86977 (13)	0.01182 (18)
C1	0.63218 (11)	0.74416 (9)	0.60624 (13)	0.00945 (17)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Co	0.01041 (10)	0.00690 (11)	0.01022 (10)	−0.00018 (6)	0.00225 (7)	0.00026 (6)
O11	0.0121 (3)	0.0070 (4)	0.0123 (3)	0.0000 (2)	0.0014 (2)	−0.0010 (3)
O21	0.0127 (3)	0.0093 (4)	0.0154 (4)	−0.0015 (3)	−0.0004 (3)	−0.0020 (3)
O12	0.0138 (3)	0.0070 (4)	0.0124 (3)	−0.0008 (3)	−0.0003 (3)	0.0009 (3)
O22	0.0134 (3)	0.0086 (4)	0.0144 (4)	0.0002 (3)	−0.0017 (3)	0.0021 (3)
N10	0.0120 (4)	0.0128 (4)	0.0128 (4)	0.0013 (3)	0.0018 (3)	−0.0006 (3)
N20	0.0125 (4)	0.0190 (5)	0.0153 (4)	−0.0012 (3)	0.0011 (3)	−0.0049 (4)
N30	0.0111 (4)	0.0136 (4)	0.0158 (4)	0.0014 (3)	0.0008 (3)	−0.0014 (3)
O1W	0.0200 (4)	0.0074 (4)	0.0180 (4)	0.0006 (3)	0.0118 (3)	0.0001 (3)
C1	0.0094 (4)	0.0088 (5)	0.0102 (4)	0.0004 (3)	0.0037 (3)	−0.0012 (3)
C2	0.0126 (4)	0.0082 (5)	0.0119 (4)	−0.0008 (3)	0.0002 (3)	−0.0002 (3)
C3	0.0096 (4)	0.0082 (5)	0.0101 (4)	−0.0003 (3)	0.0029 (3)	0.0003 (3)
C10	0.0101 (4)	0.0126 (5)	0.0123 (4)	−0.0023 (3)	0.0035 (3)	−0.0002 (3)

Geometric parameters (Å, º)

Co—O11	2.078 (1)	O11—C1	1.2655 (14)
Co—O12	2.043 (2)	O21—C1	1.2656 (14)
Co—O1W	2.105 (2)	O12—C3	1.2659 (14)
N10—C10	1.334 (2)	O22—C3	1.2567 (14)
N20—C10	1.343 (2)	C2—C1	1.5218 (16)
N30—C10	1.325 (2)	C2—C3	1.5229 (16)
Co—O12^i	2.0429 (11)	C2—H1	0.99
Co—O11^i	2.0777 (10)	C2—H2	0.99
Co—O1W^i	2.1053 (11)
O12—Co—O11	88.8 (1)	O11^i—Co—O1W^i	95.39 (4)
O12—Co—O1W	89.5 (1)	O1W—Co—O1W^i	180.0
O11—Co—O1W	95.4 (1)	C1—O11—Co	130.40 (7)
N30—C10—N10	120.2 (1)	C3—O12—Co	131.37 (7)
N30—C10—N20	120.6 (1)	C1—C2—C3	123.57 (10)
N10—C10—N20	119.2 (2)	C1—C2—H1	106.4
O12^i—Co—O12	180.0	C3—C2—H1	106.4
O12^i—Co—O11	91.18 (5)	C1—C2—H2	106.4
O12^i—Co—O11^i	88.82 (5)	C3—C2—H2	106.4
O12—Co—O11^i	91.18 (5)	H1—C2—H2	106.5
O11—Co—O11^i	180.0	O22—C3—O12	122.12 (10)
O12^i—Co—O1W	90.50 (4)	O22—C3—C2	115.15 (10)
O11^i—Co—O1W	84.61 (4)	O12—C3—C2	122.72 (9)
O12^i—Co—O1W^i	89.50 (4)	O11—C1—O21	122.56 (10)
O12—Co—O1W^i	90.50 (4)	O11—C1—C2	122.38 (9)
O11—Co—O1W^i	84.61 (4)	O21—C1—C2	115.05 (10)
C3—C2—C1—O11	−8.6 (2)	O1W^i—Co—O12—C3	−87.46 (10)
C3—C2—C1—O21	172.6 (1)	Co—O12—C3—O22	−176.83 (7)
O12^i—Co—O11—C1	174.90 (9)	Co—O12—C3—C2	4.47 (15)
O12—Co—O11—C1	−5.10 (9)	C1—C2—C3—O22	−177.85 (10)
O1W—Co—O11—C1	−94.49 (9)	C1—C2—C3—O12	0.93 (16)
O1W^i—Co—O11—C1	85.51 (9)	Co—O11—C1—O21	−170.78 (7)
O11^i—Co—O12—C3	177.14 (9)	Co—O11—C1—C2	10.54 (14)
O1W—Co—O12—C3	92.54 (10)

Symmetry code: (i) −x+1, −y+1, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N20—H201···O11	0.86	2.26	3.043 (2)	151
N20—H201···O1W^i	0.86	2.46	3.117 (2)	133
N10—H102···O21^ii	0.86	2.14	2.984 (2)	168
N10—H101···O12^iii	0.86	2.07	2.930 (2)	177
N30—H301···O22^iii	0.86	1.99	2.841 (2)	168
N30—H302···O21	0.86	2.08	2.934 (2)	173
O1W—H1W···O22^iv	0.82	1.85	2.633 (2)	160
O1W—H2W···O21^v	0.82	2.04	2.835 (2)	162

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