Triaqua­(1,10-phenanthroline-2,9-dicarboxyl­ato)cobalt(II) dihydrate

The title compound, [Co(C₁₄H₆N₂O₄)(H₂O)₃]·2H₂O, has two­fold crystallographic symmetry. The Co^II atom is in a distorted penta­gonal-bipyramidal coordination environment with two N atoms and two O atoms from a tetradentate 1,10-phenanthroline-2,9-dicarboxyl­ate ligand and one O atom from a water mol­ecule forming the penta­gonal plane, and two O atoms from two water mol­ecules occupying axial positions. In the crystal, adjacent mol­ecules are linked by O—H...O hydrogen bonds, forming a three-dimensional network.

Key indicators

• Single-crystal X-ray study
• T = 296 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.035
• wR factor = 0.098
• Data-to-parameter ratio = 14.2

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT094_ALERT_2_C Ratio of Maximum / Minimum Residual Density ....       2.08
PLAT912_ALERT_4_C Missing # of FCF Reflections Above STh/L=  0.600          6

Alert level G
PLAT083_ALERT_2_G SHELXL Second Parameter in WGHT Unusually Large.      16.29
PLAT333_ALERT_2_G Check Large Av C6-Ring C-C Dist. C5     -C7            1.41 Ang.
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          2
PLAT720_ALERT_4_G Number of Unusual/Non-Standard Labels ..........          1
PLAT764_ALERT_4_G Overcomplete CIF Bond List Detected (Rep/Expd) .       1.12 Ratio

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

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   3 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
   3 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

In recent years, the research of coordination compounds has been one of the most attractive fields due to their peculiar structures and properties (Zhao et al., 2008; Poulsen et al., 2005). Many multi-carboxylate or heterocyclic carboxylic acids are used for this purpose (Luo et al., 2009; Han et al., 2009). In the designed synthesis of the coordination compounds, H₂PDA is an excellent dicarboxylate ligand (Xie et al., 2005). In order to extend the investigation, we have prepared the Co^II complex of H₂PDA, and report its crystal structure here.

The title compound (Fig. 1) is located on a twofold axis of symmetry which passes through the Co and O3 atoms, which is isomorphous with [Mg(PDA)(H₂O)₃].2H₂O (Park et al., 2001). The seven-coordinated Co atom is in a distorted pentagonal bipyramidal geometry. Two N and two O atoms from PDA and one O atom from a water molecule define the pentagonal plane, and the two axial positions are occupied by O atoms derived from two water molecules.

Important bond distances and angles are presented in Table 1. The bond distances between Co and the PDA donor atoms [Co—O1 2.3364 (16) Å and Co—N6 2.1936 (18) Å] are significantly longer than those to the coordinated water molecules [Co—O3 2.072 (2) Å and Co—O4 2.1254 (19) Å]. This is probably due to the high rigidity of PDA as well as the high affinity of the Co^II ion to water molecules (Zhang & Chen, 2009). The carboxylate groups of the PDA ligand are almost coplanar with the phenanthroline unit as indicated by the O1—C1—C2—N6 torsion angle of 2.6 (3)°. All bond distances and angles are similar to those observed in other seven-coordinated Co^II complexes (Newkome et al., 1984; Rajput & Biradha, 2007). Adjacent molecules are linked by O—H···O hydrogen bonds, forming a three-dimensional network.

Related literature

For the structures and properties of coordination compounds, see: Zhao et al. (2008); Poulsen et al. (2005). For the use of multi-carboxylate and heterocyclic carboxylic acids in coordination chemistry, see: Luo et al. (2009); Han et al. (2009) and for the dicarboxylate ligand H₂PDA (PDA is [please define]), see: Xie et al. (2005). For the isomorphous structure [Mg(PDA)(H₂O)₃].2H₂O, see: Park et al. (2001). For the high affinity of the Co^II ion to water molecules, see: (Zhang & Chen (2009). For bond distances and angles in other seven-coordinated Co^II complexes, see: Newkome et al. (1984); Rajput & Biradha (2007). For the synthesis of 1,10-phenanthroline-2,9-dicarboxylic acid, see: De Cian et al. (2007).

S2. Experimental

1,10-Phenanthroline-2,9-dicarboxylic acid was synthesized by using a literature method (De Cian et al., 2007). To a solution of cobalt nitrate hexahydrate (0.145 g, 0.5 mmol) in water (5 ml) was added an aqueous solution (5 ml) of the ligand (0.135 g, 0.5 mmol) and sodium hydroxide (0.04 g, 1.0 mmol). The reactants were sealed in a 25-ml Teflon-lined, stainless-steel Parr bomb. The bomb was heated at 433 K for 3 days. The cool solution yielded single crystals in ca 50% yield. Anal. Calcd for C₁₄H₁₆CoN_2O9: C, 40.50; H, 3.88; N, 6.75. Found: C, 40.01; H, 4.12; N, 6.45.

S3. Refinement

The coordinated water H atoms were located in a difference Fourier map and refined with distance constraints of O—H = 0.83 (3) Å. The free water H atoms attached to oxygen atoms were placed at calculated positions and refined with the riding model, considering the position of oxygen atoms and the quantity of H atoms. The carbon-bound H atoms were placed in geometrically idealized positions, with C—H = 0.93 Å, and constrained to ride on their respective parent atoms, with Uiso(H) = 1.2 Ueq(C).

Computing details

Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); data reduction: SAINT (Bruker, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures

Fig. 1. The molecular structure of (I) showing 50% proability displacement ellipsoids and the atom-numbering scheme (Symmetry code A: -x+7/4,-y+7/4,z).

Triaqua(1,10-phenanthroline-2,9-dicarboxylato)cobalt(II) dihydrate

Crystal data

[Co(C14H6N2O4)(H2O)3]·2H2O	F(000) = 3408
Mr = 415.22	Dx = 1.688 Mg m^−3
Orthorhombic, Fddd	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -F 2uv 2vw	Cell parameters from 2624 reflections
a = 7.4093 (5) Å	θ = 3.0–25.2°
b = 18.9267 (17) Å	µ = 1.11 mm^−1
c = 46.609 (4) Å	T = 296 K
V = 6536.1 (9) Å^3	Block, yellow
Z = 16	0.20 × 0.19 × 0.17 mm

Data collection

Bruker APEXII CCD diffractometer	1520 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.032
Graphite monochromator	θmax = 27.5°, θmin = 1.8°
ϕ and ω scans	h = −9→9
9724 measured reflections	k = −24→23
1877 independent reflections	l = −45→60

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)] = 0.035	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.098	H atoms treated by a mixture of independent and constrained refinement
S = 1.06	w = 1/[σ^2(Fo^2) + (0.0494P)^2 + 16.2882P] where P = (Fo^2 + 2Fc^2)/3
1877 reflections	(Δ/σ)max = 0.001
132 parameters	Δρmax = 0.96 e Å^−3
2 restraints	Δρmin = −0.46 e Å^−3

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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	Occ. (<1)
Co1	0.8750	0.8750	0.575281 (8)	0.02703 (15)
C1	0.5006 (3)	0.79758 (12)	0.56914 (5)	0.0303 (5)
C2	0.5619 (3)	0.81188 (11)	0.53888 (5)	0.0286 (5)
C3	0.4668 (3)	0.79146 (13)	0.51428 (5)	0.0369 (5)
H3	0.3573	0.7678	0.5160	0.044*
C4	0.5356 (4)	0.80639 (13)	0.48763 (5)	0.0403 (6)
H4	0.4723	0.7936	0.4712	0.048*
C5	0.7025 (3)	0.84111 (12)	0.48536 (5)	0.0336 (5)
C6	0.7884 (3)	0.85853 (11)	0.51113 (4)	0.0283 (5)
C7	0.7938 (4)	0.85890 (13)	0.45911 (5)	0.0426 (6)
H7	0.7394	0.8479	0.4417	0.051*
H3A	0.953 (3)	0.8937 (8)	0.6302 (4)	0.063 (10)*
H5A	0.8692	0.7242	0.6386	0.075*
H5B	0.8592	0.6518	0.6227	0.075*	0.50
H5B'	0.7138	0.7061	0.6221	0.075*	0.50
H4A	1.088 (5)	0.7728 (17)	0.5770 (7)	0.049 (10)*
H4B	0.955 (5)	0.7546 (18)	0.5909 (8)	0.060 (11)*
N6	0.7184 (2)	0.84503 (10)	0.53724 (4)	0.0274 (4)
O1	0.6029 (2)	0.82142 (9)	0.58824 (4)	0.0380 (4)
O2	0.3589 (2)	0.76361 (11)	0.57280 (4)	0.0446 (5)
O3	0.8750	0.8750	0.61974 (5)	0.0459 (7)
O4	0.9892 (3)	0.77204 (10)	0.57658 (4)	0.0359 (4)
O5	0.8336 (4)	0.69890 (11)	0.62306 (5)	0.0670 (7)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Co1	0.0278 (3)	0.0337 (3)	0.0196 (2)	−0.00067 (18)	0.000	0.000
C1	0.0231 (11)	0.0333 (12)	0.0344 (12)	0.0020 (9)	0.0013 (9)	−0.0046 (9)
C2	0.0256 (11)	0.0298 (11)	0.0305 (11)	0.0043 (9)	−0.0041 (9)	−0.0060 (8)
C3	0.0325 (13)	0.0401 (13)	0.0382 (13)	−0.0006 (10)	−0.0095 (10)	−0.0084 (10)
C4	0.0463 (15)	0.0418 (14)	0.0328 (13)	0.0055 (11)	−0.0153 (11)	−0.0087 (10)
C5	0.0438 (14)	0.0321 (12)	0.0248 (11)	0.0101 (11)	−0.0069 (9)	−0.0048 (9)
C6	0.0313 (12)	0.0296 (11)	0.0239 (10)	0.0057 (9)	−0.0010 (9)	−0.0015 (8)
C7	0.0637 (17)	0.0412 (14)	0.0228 (11)	0.0069 (12)	−0.0065 (11)	−0.0037 (9)
N6	0.0261 (9)	0.0320 (9)	0.0241 (9)	0.0013 (8)	−0.0014 (7)	−0.0023 (7)
O1	0.0327 (9)	0.0544 (10)	0.0268 (8)	−0.0075 (8)	0.0024 (7)	−0.0060 (7)
O2	0.0304 (10)	0.0550 (11)	0.0483 (11)	−0.0086 (8)	0.0052 (8)	−0.0053 (8)
O3	0.0490 (16)	0.0680 (17)	0.0206 (11)	−0.0285 (14)	0.000	0.000
O4	0.0312 (11)	0.0403 (10)	0.0363 (10)	0.0012 (8)	−0.0012 (8)	0.0004 (8)
O5	0.1009 (19)	0.0418 (11)	0.0582 (13)	−0.0027 (12)	0.0008 (13)	−0.0004 (10)

Geometric parameters (Å, º)

Co1—O3	2.072 (2)	C4—C5	1.404 (4)
Co1—O4	2.1254 (19)	C4—H4	0.9300
Co1—O4^i	2.1254 (19)	C5—C6	1.399 (3)
Co1—N6^i	2.1936 (18)	C5—C7	1.438 (3)
Co1—N6	2.1936 (18)	C6—N6	1.348 (3)
Co1—O1	2.3364 (16)	C6—C6^i	1.426 (5)
Co1—O1^i	2.3364 (16)	C7—C7^i	1.349 (6)
C1—O2	1.243 (3)	C7—H7	0.9300
C1—O1	1.253 (3)	O3—H3A	0.837 (17)
C1—C2	1.506 (3)	O4—H4A	0.74 (4)
C2—N6	1.320 (3)	O4—H4B	0.79 (4)
C2—C3	1.400 (3)	O5—H5A	0.9066
C3—C4	1.372 (4)	O5—H5B	0.9119
C3—H3	0.9300	O5—H5B'	0.8988
O3—Co1—O4	88.37 (5)	C4—C3—C2	119.8 (2)
O3—Co1—O4^i	88.37 (5)	C4—C3—H3	120.1
O4—Co1—O4^i	176.75 (11)	C2—C3—H3	120.1
O3—Co1—N6^i	143.92 (5)	C3—C4—C5	119.5 (2)
O4—Co1—N6^i	92.83 (8)	C3—C4—H4	120.3
O4^i—Co1—N6^i	89.80 (7)	C5—C4—H4	120.3
O3—Co1—N6	143.92 (5)	C6—C5—C4	116.5 (2)
O4—Co1—N6	89.80 (7)	C6—C5—C7	117.5 (2)
O4^i—Co1—N6	92.83 (8)	C4—C5—C7	126.0 (2)
N6^i—Co1—N6	72.16 (10)	N6—C6—C5	123.7 (2)
O3—Co1—O1	75.02 (4)	N6—C6—C6^i	115.43 (12)
O4—Co1—O1	86.46 (8)	C5—C6—C6^i	120.83 (14)
O4^i—Co1—O1	92.69 (7)	C7^i—C7—C5	121.69 (15)
N6^i—Co1—O1	141.06 (6)	C7^i—C7—H7	119.2
N6—Co1—O1	68.91 (6)	C5—C7—H7	119.2
O3—Co1—O1^i	75.02 (4)	C2—N6—C6	118.72 (18)
O4—Co1—O1^i	92.69 (7)	C2—N6—Co1	122.73 (14)
O4^i—Co1—O1^i	86.46 (8)	C6—N6—Co1	118.50 (15)
N6^i—Co1—O1^i	68.91 (6)	C1—O1—Co1	119.62 (15)
N6—Co1—O1^i	141.06 (6)	Co1—O3—H3A	125.6 (15)
O1—Co1—O1^i	150.03 (8)	Co1—O4—H4A	112 (3)
O2—C1—O1	126.8 (2)	Co1—O4—H4B	106 (2)
O2—C1—C2	118.4 (2)	H4A—O4—H4B	108 (3)
O1—C1—C2	114.7 (2)	H5A—O5—H5B	118.1
N6—C2—C3	121.7 (2)	H5A—O5—H5B'	104.2
N6—C2—C1	113.83 (18)	H5B—O5—H5B'	110.7
C3—C2—C1	124.5 (2)
O2—C1—C2—N6	−176.6 (2)	C6^i—C6—N6—Co1	0.2 (3)
O1—C1—C2—N6	2.6 (3)	O3—Co1—N6—C2	−2.8 (2)
O2—C1—C2—C3	2.2 (3)	O4—Co1—N6—C2	84.14 (17)
O1—C1—C2—C3	−178.6 (2)	O4^i—Co1—N6—C2	−93.94 (17)
N6—C2—C3—C4	−0.5 (4)	N6^i—Co1—N6—C2	177.2 (2)
C1—C2—C3—C4	−179.2 (2)	O1—Co1—N6—C2	−2.14 (16)
C2—C3—C4—C5	1.0 (4)	O1^i—Co1—N6—C2	178.19 (14)
C3—C4—C5—C6	−0.1 (3)	O3—Co1—N6—C6	179.93 (11)
C3—C4—C5—C7	178.5 (2)	O4—Co1—N6—C6	−93.11 (16)
C4—C5—C6—N6	−1.3 (3)	O4^i—Co1—N6—C6	88.81 (16)
C7—C5—C6—N6	179.9 (2)	N6^i—Co1—N6—C6	−0.07 (11)
C4—C5—C6—C6^i	177.6 (2)	O1—Co1—N6—C6	−179.40 (17)
C7—C5—C6—C6^i	−1.2 (4)	O1^i—Co1—N6—C6	0.9 (2)
C6—C5—C7—C7^i	0.1 (4)	O2—C1—O1—Co1	174.59 (19)
C4—C5—C7—C7^i	−178.6 (3)	C2—C1—O1—Co1	−4.5 (3)
C3—C2—N6—C6	−0.9 (3)	O3—Co1—O1—C1	−176.70 (18)
C1—C2—N6—C6	178.00 (18)	O4—Co1—O1—C1	−87.44 (18)
C3—C2—N6—Co1	−178.11 (16)	O4^i—Co1—O1—C1	95.71 (18)
C1—C2—N6—Co1	0.7 (3)	N6^i—Co1—O1—C1	2.7 (2)
C5—C6—N6—C2	1.8 (3)	N6—Co1—O1—C1	3.71 (16)
C6^i—C6—N6—C2	−177.2 (2)	O1^i—Co1—O1—C1	−176.70 (18)
C5—C6—N6—Co1	179.17 (16)

Symmetry code: (i) −x+7/4, −y+7/4, z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3A···O1^ii	0.837 (17)	1.957 (16)	2.778 (2)	167 (2)
O5—H5A···O2^iii	0.91	1.95	2.837 (3)	164
O5—H5B···O5^iv	0.91	1.93	2.803 (4)	161
O5—H5B′···O5^iii	0.90	2.22	3.096 (6)	165
O4—H4A···O2^v	0.74 (4)	2.02 (4)	2.750 (3)	171 (4)
O4—H4B···O5	0.79 (4)	2.04 (4)	2.818 (3)	169 (3)

Symmetry codes: (ii) x+1/2, −y+7/4, −z+5/4; (iii) −x+5/4, y, −z+5/4; (iv) x, −y+5/4, −z+5/4; (v) x+1, y, z.