Tetra­aqua­bis(5-hydroxy­nicotinato-κN)cadmium(II)

The title compound, [Cd(C₆H₄NO₃)₂(H₂O)₄], was obtained by the reaction of cadmium chloride with 5-hydroxy­nicotinic acid. The Cd^II atom is located on an inversion centre and is coordinated by two N atoms from two 5-hydroxy­nicotinic acid ligands and four water mol­ecules in a distorted octa­hedral geometry. The structure is stabilized by inter­molecular O—H...O hydrogen bonds, forming a three-dimensional network.

Key indicators

• Single-crystal X-ray study
• T = 296 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.016
• wR factor = 0.042
• Data-to-parameter ratio = 13.4

checkCIF/PLATON results

No syntax errors found



Alert level C
            Value of measurement temperature given =   296.000
            Value of melting point given =     0.000
PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor ....       2.12
PLAT153_ALERT_1_C The su's on the Cell Axes   are Equal (x 100000)         10 Ang.
PLAT154_ALERT_1_C The su's on the Cell Angles are Equal  (x 10000)        100 Deg.
PLAT180_ALERT_4_C Check Cell Rounding: # of Values Ending with 0 =          6

Alert level G
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          7
PLAT720_ALERT_4_G Number of Unusual/Non-Standard Labels ..........          4

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

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

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S1. Comment

There is intense research on the synthesis of the cadmium metal compounds for their interesting photoluminescent properties. A large number of these compounds have been synthesized (He et al., 2008; Zora et al., 2006; Kang et al.,2007; Zhang et al., 2006).

As illustrated in Fig. 1, the Cd(II) atom is coordinated by two nitrogen atoms from two 5-hydroxynicotinic acid ligands and four water molecules. Four coordinated atoms of O1W, O2W, O1WA and O2WA constitute the base of the octahedral, whereas N1 and N1A atoms occupy the apical position. The intermolecular hydrogen bonds play an important role in the formation of the three-dimensional network. As shown in Fig. 2, the intermolecular O—H···O hydrogen bonds link the neighboring molecules to a three-dimensional network.

Related literature

For cadmium componds and their photoluminescent properties, see: He et al. (2008); Kang et al. (2007); Zhang et al. (2006); Zora et al. (2006).

S2. Experimental

A mixture of 0.5 mmol 5-hydroxynicotinic acid and 0.5 mmol of cadmium chloride in 10 ml distilled water was stirred for 30 min at 323 K, then the reaction mixture was filtered and well shaped colourless crystals of the title compound was obtained from the mother liquor by slow evaporation at room temperature for several days.

S3. Refinement

The H atoms bonded to C atoms were positioned geometrically [aromatic C—H = 0.93 Å and aliphatic C—H = 0.97 Å, U_iso(H) = 1.2U_eq(C)]. The H atoms bonded to O atoms were located in a difference Fourier maps and refined with O—H distance restraints of 0.85 and U_iso(H) = 1.5U_eq(O).

Computing details

Data collection: SMART (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: XPREP (Bruker, 2004); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures

	Fig. 1. A view of the molecule of (I), showing the atom-labelling scheme, displacement ellipsoids are shown at the 30% probability level. [Symmetry code: (A) -x + 1, -y + 1, -z + 2].
	Fig. 2. A view of the three dimensional framework of the title compound. The O—H···O interactions are depicted by dashed lines.

Tetraaquabis(5-hydroxynicotinato-κN)cadmium(II)

Crystal data

[Cd(C6H4NO3)2(H2O)4]	Z = 1
Mr = 460.68	F(000) = 230
Triclinic, P1	Dx = 1.982 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.2190 (1) Å	Cell parameters from 5615 reflections
b = 7.2510 (1) Å	θ = 2.5–27.5°
c = 8.9260 (1) Å	µ = 1.48 mm^−1
α = 70.377 (1)°	T = 296 K
β = 68.154 (1)°	Sheet, colourless
γ = 65.717 (1)°	0.27 × 0.17 × 0.07 mm
V = 385.97 (1) Å^3

Data collection

Bruker APEXII diffractometer	1759 independent reflections
Radiation source: fine-focus sealed tube	1754 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.017
ω scans	θmax = 27.5°, θmin = 2.5°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −9→9
Tmin = 0.667, Tmax = 0.903	k = −9→9
6067 measured reflections	l = −11→11

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)] = 0.016	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.042	H atoms treated by a mixture of independent and constrained refinement
S = 1.09	w = 1/[σ^2(Fo^2) + (0.0249P)^2 + 0.1253P] where P = (Fo^2 + 2Fc^2)/3
1759 reflections	(Δ/σ)max < 0.001
131 parameters	Δρmax = 0.36 e Å^−3
7 restraints	Δρmin = −0.34 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
Cd1	0.5000	0.5000	1.0000	0.02626 (6)
O1	0.8938 (2)	0.7990 (2)	0.32463 (16)	0.0427 (3)
O1W	0.2684 (3)	0.3168 (3)	1.07212 (17)	0.0482 (4)
H1WA	0.287 (5)	0.249 (4)	1.009 (3)	0.072*
H1WB	0.209 (5)	0.270 (4)	1.163 (2)	0.072*
O2	0.6901 (2)	0.8709 (2)	0.16430 (15)	0.0429 (3)
O2W	0.7595 (2)	0.2074 (2)	0.92481 (18)	0.0478 (4)
H2WA	0.881 (3)	0.189 (4)	0.865 (3)	0.072*
H2WB	0.762 (5)	0.098 (3)	0.994 (3)	0.072*
O3	0.0066 (2)	0.7675 (2)	0.58671 (17)	0.0400 (3)
H3	0.002 (4)	0.785 (4)	0.491 (2)	0.053 (7)*
N1	0.4459 (2)	0.6297 (2)	0.74305 (16)	0.0264 (3)
C1	0.5945 (2)	0.6740 (2)	0.60554 (19)	0.0267 (3)
H1A	0.7280	0.6483	0.6138	0.032*
C2	0.5560 (2)	0.7568 (2)	0.45137 (18)	0.0245 (3)
C3	0.3595 (3)	0.7885 (2)	0.43778 (19)	0.0263 (3)
H3A	0.3310	0.8402	0.3354	0.032*
C4	0.2061 (2)	0.7415 (2)	0.5802 (2)	0.0270 (3)
C5	0.2549 (2)	0.6655 (3)	0.73035 (19)	0.0276 (3)
H5A	0.1507	0.6383	0.8260	0.033*
C6	0.7273 (3)	0.8123 (2)	0.30121 (19)	0.0288 (3)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cd1	0.02499 (9)	0.03841 (10)	0.01604 (8)	−0.01493 (7)	−0.00552 (6)	−0.00099 (6)
O1	0.0313 (6)	0.0688 (9)	0.0266 (6)	−0.0259 (6)	−0.0010 (5)	−0.0044 (6)
O1W	0.0589 (9)	0.0749 (10)	0.0276 (6)	−0.0484 (8)	−0.0017 (6)	−0.0091 (7)
O2	0.0587 (8)	0.0592 (8)	0.0199 (6)	−0.0385 (7)	−0.0088 (5)	0.0028 (5)
O2W	0.0368 (7)	0.0424 (7)	0.0347 (7)	−0.0075 (6)	0.0072 (6)	0.0013 (6)
O3	0.0285 (6)	0.0620 (8)	0.0326 (7)	−0.0220 (6)	−0.0135 (5)	0.0007 (6)
N1	0.0258 (6)	0.0362 (7)	0.0187 (6)	−0.0141 (5)	−0.0068 (5)	−0.0018 (5)
C1	0.0252 (7)	0.0376 (8)	0.0208 (7)	−0.0155 (6)	−0.0064 (6)	−0.0037 (6)
C2	0.0278 (7)	0.0271 (7)	0.0195 (7)	−0.0128 (6)	−0.0046 (6)	−0.0033 (5)
C3	0.0312 (7)	0.0288 (7)	0.0207 (7)	−0.0120 (6)	−0.0109 (6)	−0.0005 (5)
C4	0.0249 (7)	0.0305 (7)	0.0281 (7)	−0.0112 (6)	−0.0107 (6)	−0.0026 (6)
C5	0.0254 (7)	0.0358 (8)	0.0219 (7)	−0.0143 (6)	−0.0053 (6)	−0.0023 (6)
C6	0.0340 (8)	0.0319 (8)	0.0206 (7)	−0.0166 (6)	−0.0025 (6)	−0.0038 (6)

Geometric parameters (Å, º)

Cd1—O2W	2.2830 (14)	O3—C4	1.3543 (19)
Cd1—O2W^i	2.2830 (14)	O3—H3	0.830 (17)
Cd1—N1^i	2.2831 (13)	N1—C5	1.335 (2)
Cd1—N1	2.2831 (13)	N1—C1	1.3411 (19)
Cd1—O1W	2.3291 (13)	C1—C2	1.387 (2)
Cd1—O1W^i	2.3291 (13)	C1—H1A	0.9300
O1—C6	1.255 (2)	C2—C3	1.385 (2)
O1W—H1WA	0.809 (17)	C2—C6	1.517 (2)
O1W—H1WB	0.794 (17)	C3—C4	1.389 (2)
O2—C6	1.244 (2)	C3—H3A	0.9300
O2W—H2WA	0.823 (17)	C4—C5	1.386 (2)
O2W—H2WB	0.822 (17)	C5—H5A	0.9300
O2W—Cd1—O2W^i	180.0	C5—N1—C1	118.64 (13)
O2W—Cd1—N1^i	87.79 (5)	C5—N1—Cd1	117.86 (10)
O2W^i—Cd1—N1^i	92.21 (5)	C1—N1—Cd1	123.49 (10)
O2W—Cd1—N1	92.21 (5)	N1—C1—C2	122.29 (14)
O2W^i—Cd1—N1	87.79 (5)	N1—C1—H1A	118.9
N1^i—Cd1—N1	180.000 (1)	C2—C1—H1A	118.9
O2W—Cd1—O1W	85.72 (6)	C3—C2—C1	118.97 (14)
O2W^i—Cd1—O1W	94.28 (6)	C3—C2—C6	121.06 (14)
N1^i—Cd1—O1W	90.57 (5)	C1—C2—C6	119.96 (14)
N1—Cd1—O1W	89.43 (5)	C2—C3—C4	118.68 (14)
O2W—Cd1—O1W^i	94.28 (6)	C2—C3—H3A	120.7
O2W^i—Cd1—O1W^i	85.72 (6)	C4—C3—H3A	120.7
N1^i—Cd1—O1W^i	89.43 (5)	O3—C4—C5	115.78 (14)
N1—Cd1—O1W^i	90.57 (5)	O3—C4—C3	125.40 (14)
O1W—Cd1—O1W^i	180.0	C5—C4—C3	118.81 (14)
Cd1—O1W—H1WA	117 (2)	N1—C5—C4	122.55 (14)
Cd1—O1W—H1WB	127 (2)	N1—C5—H5A	118.7
H1WA—O1W—H1WB	110 (2)	C4—C5—H5A	118.7
Cd1—O2W—H2WA	131 (2)	O2—C6—O1	125.02 (15)
Cd1—O2W—H2WB	117 (2)	O2—C6—C2	117.26 (15)
H2WA—O2W—H2WB	105 (2)	O1—C6—C2	117.71 (14)
C4—O3—H3	108.2 (19)
O2W—Cd1—N1—C5	119.15 (12)	C1—C2—C3—C4	1.8 (2)
O2W^i—Cd1—N1—C5	−60.85 (12)	C6—C2—C3—C4	−177.83 (14)
O1W—Cd1—N1—C5	33.45 (13)	C2—C3—C4—O3	178.81 (15)
O1W^i—Cd1—N1—C5	−146.55 (13)	C2—C3—C4—C5	0.2 (2)
O2W—Cd1—N1—C1	−61.78 (13)	C1—N1—C5—C4	1.7 (2)
O2W^i—Cd1—N1—C1	118.22 (13)	Cd1—N1—C5—C4	−179.16 (12)
O1W—Cd1—N1—C1	−147.47 (13)	O3—C4—C5—N1	179.22 (15)
O1W^i—Cd1—N1—C1	32.53 (13)	C3—C4—C5—N1	−2.1 (2)
C5—N1—C1—C2	0.5 (2)	C3—C2—C6—O2	−5.8 (2)
Cd1—N1—C1—C2	−178.62 (11)	C1—C2—C6—O2	174.61 (15)
N1—C1—C2—C3	−2.2 (2)	C3—C2—C6—O1	173.06 (16)
N1—C1—C2—C6	177.42 (14)	C1—C2—C6—O1	−6.6 (2)

Symmetry code: (i) −x+1, −y+1, −z+2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1W—H1WA···O2^ii	0.81 (2)	1.94 (2)	2.742 (2)	171 (3)
O1W—H1WB···O3^iii	0.79 (2)	2.20 (2)	2.9728 (19)	164 (3)
O2W—H2WA···O1^iv	0.82 (2)	1.87 (2)	2.6556 (18)	160 (3)
O2W—H2WB···O2^v	0.82 (2)	1.93 (2)	2.7349 (19)	165 (3)
O3—H3···O1^vi	0.83 (2)	1.88 (2)	2.6637 (19)	157 (3)

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