Diaqua­bis[3-(2-pyrid­yl)-1H-pyrazole- κ²N²,N³]cadmium(II) dinitrate

In the title centrosymmetric compound, [Cd(C₈H₇N₃)₂(H₂O)₂](NO₃)₂, the Cd^II atom lies on a center of symmetry and is six-coordinated by four N donors from two distinct chelating 3-(2-pyrid­yl)-1H-pyrazole ligands and two O atoms from two water mol­ecules, in a distorted octa­hedral geometry. The Cd^II mononuclear units and nitrate ions are linked through inter­molecular O—H...O, N—H...O and C—H...O hydrogen-bonding inter­actions, forming a three-dimensional framework.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.024
• wR factor = 0.057
• Data-to-parameter ratio = 15.7

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT230_ALERT_2_C Hirshfeld Test Diff for    N3     -   C8      ..       5.45 su
PLAT244_ALERT_4_C Low   'Solvent' Ueq as Compared to Neighbors for         N4
PLAT720_ALERT_4_C Number of Unusual/Non-Standard Label(s) ........          2
PLAT790_ALERT_4_C Centre of Gravity not Within Unit Cell: Resd.  #          2
              N O3

Alert level G
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_G Check the Reported _diffrn_ambient_temperature .        293 K
PLAT794_ALERT_5_G Check Predicted Bond Valency for Cd1         (2)       2.17

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   4 ALERT level C = Check and explain
   3 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
   0 ALERT type 3 Indicator that the structure quality may be low
   3 ALERT type 4 Improvement, methodology, query or suggestion
   1 ALERT type 5 Informative message, check

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S1. Comment

In recent years, much attention has been focused on the synthetic approach and the structural control of metal-organic coordination architectures with ligands based on pyrazolyl-pyridine chelating units (Steel, 2005; Ward et al., 2001). Many novel functional complexes with 3-(2-pyridyl)-1H-pyrazole (L) and/or 3-(2-pyridyl)pyrazole ligands have been reported (Bell et al., 2003; Paul et al., 2004; Singh et al., 2003; Ward et al., 2001). Recently, we have used 3-(2-pyridyl)-1H-pyrazole and its derivatives to obtain complexes with various structures, including discrete multinuclear molecules, one- and two-dimensional coordination polymers, which exhibit luminescent and magnetic properties (Hu et al., 2006; Liu et al., 2006, 2007; Zou et al., 2004,2005,2006). Now we report here the crystal structure of a cadmium(II) complex of L ligand, [Cd(L)₂(H₂O)₂]²⁺.2NO₃^2-, the title compound.

In the title centrosymmetric complex, the Cd^II center is six-coordinated by four N donors from two L ligands and two O atoms from two water molecules (Table 1). The L ligand chelates to the Cd^II atom, which lies on an inversion center, in a nearly isobidentate manner [Cd1—N2 = 2.3539 (18) Å and Cd1—N3 = 2.2900 (17) Å]. The two other coordination sites are occupied by two water molecules. The coordination geometry around the Cd^II center can be described as a distorted octahedron (Fig. 1). The distortion from the ideal octahedral geometry is evident from the bond angles given in Table 1.

The Cd^II mononuclear units are linked to nitrate anions through intermolecular O–H···O, N–H···O and C–H···O (Desiraju & Steiner, 1999) hydrogen-bonding interactions (Table 2) involving the coordinated water molecules and free nitrate anions, forming a three-dimensional framework (Fig. 2).

Related literature

For related literature, see: Bell et al. (2003); Hu et al. (2006); Liu et al. (2006, 2007); Paul et al. (2004); Steel (2005); Ward et al. (2001); Zou et al. (2004, 2005, 2006). For hydrogen-bond details, see: Desiraju & Steiner (1999).

S2. Experimental

3-(2-Pyridyl)-1H-pyrazole) (0.1 mmol) and Cd(NO₃)₂ (0.1 mmol) were added to methanol (15 ml) containing water (5 ml). In few minutes, a white solid appeared which then was filtered. The resulting solution was kept at room temperature. Colourless single crystals of the title compound suitable for X-ray analysis were obtained by slow evaporation of the solvent after several days (yield: 30%). Analysis calculated for (C₁₆H₁₈CdN₈O₈): C 34.15, H 3.22, N 19.91%; found: C 34.26, H 3.14, N 18.77%.

S3. Refinement

H atoms of the water molecule were located in a difference map and were allowed to ride on the parent atom, with U_iso = 1.2U_eq(O). The remaining H atoms were included in calculated positions and treated in the subsequent refinement as riding atoms, with C-H = 0.93 Å, N-H = 0.86 Å and i>U_iso(H) = 1.2U_eq(C,N).

Computing details

Data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 1998); data reduction: SAINT (Bruker, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 1998); software used to prepare material for publication: SHELXTL (Bruker, 1998) and PLATON (Spek, 2003).

Figures

	Fig. 1. The molecular structure of the title compound. Displacement ellipsoids are drawn at the 30% probability level. Atoms labelled with the suffix A are generated by the symmetry operation (1 - x, 2 - y, 1 - z).
	Fig. 2. Part of the crystal packing in the title compound. Hydrogen bonds are shown as dashed lines. For clarity only H atoms involved in the interactions are shown.

Diaquabis[3-(2-pyridyl)-1H-pyrazole- κ²N²,N³]cadmium(II) dinitrate

Crystal data

[Cd(C8H7N3)2(H2O)2](NO3)2	F(000) = 564
Mr = 562.78	Dx = 1.790 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 666 reflections
a = 8.1283 (16) Å	θ = 2.3–22.5°
b = 10.461 (2) Å	µ = 1.11 mm^−1
c = 12.309 (3) Å	T = 293 K
β = 94.04 (3)°	Block, colourless
V = 1044.0 (4) Å^3	0.22 × 0.18 × 0.16 mm
Z = 2

Data collection

Bruker SMART CCD area-detector diffractometer	2377 independent reflections
Radiation source: fine-focus sealed tube	1810 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.032
ϕ and ω scans	θmax = 27.5°, θmin = 2.6°
Absorption correction: multi-scan (SADABS; Bruker, 1998)	h = −10→10
Tmin = 0.795, Tmax = 0.845	k = −14→13
6639 measured reflections	l = −15→15

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)] = 0.025	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.057	H-atom parameters constrained
S = 0.93	w = 1/[σ^2(Fo^2) + (0.0278P)^2] where P = (Fo^2 + 2Fc^2)/3
2377 reflections	(Δ/σ)max = 0.001
151 parameters	Δρmax = 0.43 e Å^−3
0 restraints	Δρmin = −0.25 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	1.0000	0.5000	0.03912 (8)
C1	0.7329 (3)	0.6068 (2)	0.5375 (2)	0.0564 (6)
H1A	0.8148	0.5450	0.5353	0.068*
C2	0.5940 (3)	0.5968 (2)	0.5903 (2)	0.0559 (6)
H2A	0.5605	0.5283	0.6315	0.067*
C3	0.5102 (3)	0.7142 (2)	0.56918 (17)	0.0423 (5)
C4	0.3529 (3)	0.7578 (2)	0.60517 (17)	0.0419 (5)
C5	0.2468 (3)	0.6775 (2)	0.6560 (2)	0.0593 (7)
H5A	0.2746	0.5923	0.6686	0.071*
C6	0.1009 (3)	0.7249 (3)	0.6875 (2)	0.0669 (8)
H6A	0.0294	0.6719	0.7224	0.080*
C7	0.0596 (3)	0.8489 (3)	0.6681 (2)	0.0610 (7)
H7A	−0.0398	0.8816	0.6890	0.073*
C8	0.1675 (3)	0.9247 (2)	0.6172 (2)	0.0536 (6)
H8A	0.1393	1.0095	0.6030	0.064*
N1	0.7326 (2)	0.72088 (19)	0.48873 (18)	0.0529 (5)
H1B	0.8102	0.7479	0.4506	0.064*
N2	0.5972 (2)	0.78798 (17)	0.50643 (15)	0.0444 (4)
N3	0.3126 (2)	0.88119 (17)	0.58709 (14)	0.0416 (4)
N4	−0.4146 (2)	0.79729 (19)	0.84554 (14)	0.0449 (4)
O1	−0.4736 (2)	0.69650 (17)	0.87871 (16)	0.0685 (5)
O2	−0.2770 (2)	0.7968 (2)	0.81080 (17)	0.0818 (6)
O3	−0.4952 (3)	0.89658 (17)	0.84575 (19)	0.0767 (6)
O1W	0.3392 (2)	0.96843 (16)	0.33963 (14)	0.0583 (5)
H1WA	0.3421	1.0117	0.2814	0.070*
H1WB	0.2902	0.8984	0.3236	0.070*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cd1	0.03983 (12)	0.03118 (11)	0.04703 (13)	−0.00183 (10)	0.00790 (8)	0.00727 (10)
C1	0.0514 (14)	0.0395 (13)	0.0765 (18)	0.0158 (11)	−0.0076 (13)	−0.0038 (12)
C2	0.0613 (15)	0.0411 (12)	0.0636 (16)	0.0000 (12)	−0.0068 (12)	0.0072 (12)
C3	0.0481 (12)	0.0337 (10)	0.0436 (12)	−0.0016 (10)	−0.0064 (9)	0.0007 (9)
C4	0.0517 (12)	0.0379 (11)	0.0353 (11)	−0.0125 (10)	−0.0017 (9)	0.0024 (9)
C5	0.0677 (17)	0.0509 (14)	0.0596 (15)	−0.0166 (13)	0.0075 (13)	0.0097 (12)
C6	0.0603 (16)	0.075 (2)	0.0674 (17)	−0.0231 (15)	0.0199 (14)	0.0018 (15)
C7	0.0428 (13)	0.0773 (19)	0.0655 (16)	−0.0073 (13)	0.0222 (12)	−0.0123 (15)
C8	0.0530 (13)	0.0493 (14)	0.0594 (15)	−0.0037 (12)	0.0100 (12)	−0.0038 (12)
N1	0.0448 (10)	0.0454 (11)	0.0690 (13)	0.0079 (9)	0.0072 (9)	−0.0014 (10)
N2	0.0426 (10)	0.0353 (9)	0.0553 (11)	0.0040 (8)	0.0036 (8)	0.0031 (9)
N3	0.0402 (9)	0.0412 (10)	0.0440 (10)	−0.0051 (8)	0.0069 (8)	0.0009 (8)
N4	0.0498 (11)	0.0432 (10)	0.0414 (10)	−0.0084 (9)	0.0017 (8)	−0.0012 (8)
O1	0.0753 (12)	0.0446 (10)	0.0860 (13)	−0.0143 (9)	0.0072 (10)	0.0178 (10)
O2	0.0574 (11)	0.1002 (16)	0.0920 (15)	−0.0163 (11)	0.0359 (10)	−0.0100 (13)
O3	0.0805 (13)	0.0438 (10)	0.1049 (16)	0.0108 (10)	−0.0012 (11)	−0.0007 (11)
O1W	0.0690 (11)	0.0541 (10)	0.0504 (9)	−0.0187 (8)	−0.0056 (8)	0.0104 (8)

Geometric parameters (Å, º)

Cd1—N3	2.2900 (17)	C5—C6	1.367 (4)
Cd1—N3^i	2.2900 (17)	C5—H5A	0.93
Cd1—O1W^i	2.3133 (18)	C6—C7	1.357 (4)
Cd1—O1W	2.3133 (18)	C6—H6A	0.93
Cd1—N2	2.3539 (18)	C7—C8	1.366 (3)
Cd1—N2^i	2.3539 (18)	C7—H7A	0.93
C1—N1	1.336 (3)	C8—N3	1.341 (3)
C1—C2	1.346 (4)	C8—H8A	0.93
C1—H1A	0.93	N1—N2	1.337 (2)
C2—C3	1.420 (3)	N1—H1B	0.86
C2—H2A	0.93	N4—O2	1.226 (2)
C3—N2	1.330 (3)	N4—O3	1.228 (2)
C3—C4	1.456 (3)	N4—O1	1.239 (2)
C4—N3	1.346 (3)	O1W—H1WA	0.85
C4—C5	1.384 (3)	O1W—H1WB	0.85
N3—Cd1—N3^i	180	C6—C5—C4	119.3 (3)
N3—Cd1—O1W^i	91.87 (6)	C6—C5—H5A	120.4
N3^i—Cd1—O1W^i	88.13 (6)	C4—C5—H5A	120.4
N3—Cd1—O1W	88.13 (6)	C7—C6—C5	120.4 (2)
N3^i—Cd1—O1W	91.87 (6)	C7—C6—H6A	119.8
O1W^i—Cd1—O1W	180	C5—C6—H6A	119.8
N3—Cd1—N2	72.87 (6)	C6—C7—C8	118.4 (2)
N3^i—Cd1—N2	107.13 (6)	C6—C7—H7A	120.8
O1W^i—Cd1—N2	86.43 (7)	C8—C7—H7A	120.8
O1W—Cd1—N2	93.57 (7)	N3—C8—C7	122.4 (2)
N3—Cd1—N2^i	107.13 (6)	N3—C8—H8A	118.8
N3^i—Cd1—N2^i	72.87 (6)	C7—C8—H8A	118.8
O1W^i—Cd1—N2^i	93.57 (7)	C1—N1—N2	111.8 (2)
O1W—Cd1—N2^i	86.43 (7)	C1—N1—H1B	124.1
N2—Cd1—N2^i	180	N2—N1—H1B	124.1
N1—C1—C2	108.2 (2)	C3—N2—N1	105.52 (17)
N1—C1—H1A	125.9	C3—N2—Cd1	112.07 (13)
C2—C1—H1A	125.9	N1—N2—Cd1	140.14 (14)
C1—C2—C3	104.6 (2)	C8—N3—C4	119.2 (2)
C1—C2—H2A	127.7	C8—N3—Cd1	124.93 (16)
C3—C2—H2A	127.7	C4—N3—Cd1	115.83 (14)
N2—C3—C2	109.9 (2)	O2—N4—O3	120.3 (2)
N2—C3—C4	120.58 (18)	O2—N4—O1	119.7 (2)
C2—C3—C4	129.5 (2)	O3—N4—O1	120.0 (2)
N3—C4—C5	120.3 (2)	Cd1—O1W—H1WA	126.6
N3—C4—C3	117.32 (18)	Cd1—O1W—H1WB	123.3
C5—C4—C3	122.4 (2)	H1WA—O1W—H1WB	107.7
N1—C1—C2—C3	0.1 (3)	O1W^i—Cd1—N2—C3	83.94 (15)
C1—C2—C3—N2	0.3 (3)	O1W—Cd1—N2—C3	−96.06 (15)
C1—C2—C3—C4	179.9 (2)	N3—Cd1—N2—N1	−168.5 (2)
N2—C3—C4—N3	−10.1 (3)	N3^i—Cd1—N2—N1	11.5 (2)
C2—C3—C4—N3	170.3 (2)	O1W^i—Cd1—N2—N1	−75.4 (2)
N2—C3—C4—C5	169.8 (2)	O1W—Cd1—N2—N1	104.6 (2)
C2—C3—C4—C5	−9.8 (4)	C7—C8—N3—C4	1.5 (4)
N3—C4—C5—C6	0.1 (4)	C7—C8—N3—Cd1	179.34 (19)
C3—C4—C5—C6	−179.9 (2)	C5—C4—N3—C8	−1.1 (3)
C4—C5—C6—C7	0.7 (4)	C3—C4—N3—C8	178.82 (19)
C5—C6—C7—C8	−0.3 (4)	C5—C4—N3—Cd1	−179.15 (17)
C6—C7—C8—N3	−0.8 (4)	C3—C4—N3—Cd1	0.8 (2)
C2—C1—N1—N2	−0.4 (3)	O1W^i—Cd1—N3—C8	100.70 (18)
C2—C3—N2—N1	−0.5 (2)	O1W—Cd1—N3—C8	−79.30 (18)
C4—C3—N2—N1	179.83 (19)	N2—Cd1—N3—C8	−173.62 (19)
C2—C3—N2—Cd1	−166.96 (15)	N2^i—Cd1—N3—C8	6.38 (19)
C4—C3—N2—Cd1	13.4 (2)	O1W^i—Cd1—N3—C4	−81.39 (16)
C1—N1—N2—C3	0.6 (3)	O1W—Cd1—N3—C4	98.61 (16)
C1—N1—N2—Cd1	160.79 (18)	N2—Cd1—N3—C4	4.29 (14)
N3—Cd1—N2—C3	−9.12 (14)	N2^i—Cd1—N3—C4	−175.71 (14)
N3^i—Cd1—N2—C3	170.88 (14)

Symmetry code: (i) −x+1, −y+2, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1W—H1WA···O2^ii	0.85	2.34	3.096 (3)	148
O1W—H1WA···O3^ii	0.85	2.28	3.036 (3)	149
O1W—H1WB···O2^iii	0.85	2.12	2.944 (3)	164
N1—H1B···O1^iv	0.86	2.10	2.956 (3)	171
N1—H1B···O3^iv	0.86	2.60	3.170 (3)	125
O1W—H1WB···O1^iii	0.85	2.50	3.138 (2)	133
C1—H1A···O3^v	0.93	2.53	3.319 (3)	143
C8—H8A···O1^vi	0.93	2.39	3.253 (3)	153

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