Di-μ-nicotinato-κ2N:O;κ2O:N-bis­[aqua­(ethyl­enediamine-κ2N,N′)(nicotinato-κN)cadmium(II)] dihydrate

Moncol, J.; Mikloš, D.; Segla, P.; Koman, M.

doi:10.1107/S1600536808009756

metal-organic compounds

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ISSN: 2056-9890

Volume 64| Part 5| May 2008| Pages m665-m666

doi:10.1107/S1600536808009756

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Di-μ-nicotinato-κ²N:O;κ²O:N-bis[aqua(ethylenediamine-κ²N,N′)(nicotinato-κN)cadmium(II)] dihydrate

Jan Moncol,^a ^* Dušan Mikloš,^a Peter Segla ^a and Marian Koman ^a

^aDepartment of Inorganic Chemistry, Slovak Technical University, Radlinského 9, SK-812 37 Bratislava, Slovakia
^*Correspondence e-mail: jan.moncol@stuba.sk

(Received 2 April 2008; accepted 9 April 2008; online 16 April 2008)

The dinuclear molecule of the title compound, [Cd₂(C₆H₄NO₂)₄(C₂H₈N₂)₂(H₂O)₂]·2H₂O, lies on an inversion centre and forms 12-membered (CdNC₃O)₂ metallacycles with the two Cd²⁺ ions bridged by two nicotinate ligands. Both Cd²⁺ ions display coordination polyhedra with a distorted octahedral geometry that includes two pyridine N atoms from bridging and terminal nicotinate anions, two amine N atoms from chelating ethylenediamine ligands, carboxylate O atoms from bridging nicotinate anions and water O atoms. Intermolecular O—H⋯O and N—H⋯O hydrogen bonds result in the formation of a three-dimensional network, and π–π stacking interactions are observed between symmetry-related pyridine rings of bridging as well as terminal nicotinate anions (the centroid–centroid distances are 3.59 and 3.69 Å, respectively, and the distances between parallel planes of the stacked pyridine rings are 3.53 and 3.43 Å, respectively). The two methylene groups of the ethylenediamine ligand are disordered over two positions; the site occupancy factors are ca 0.8 and 0.2.

Related literature

For related literature, see: Bernstein et al. (1995 ); Chen (2003 ); Clegg et al. (1995 ); Evans & Lin (2001 ); Janiak (2000 ); Kang et al. (2007 ); Liang & Li (2005 ); Lu & Kohler (2002 ); Lu et al. (2007 ); Luo et al. (2004 ); Song et al. (2006 ); Xian et al. (2007 ); Zhang et al. (1996 ); Zhang et al. (2004 ). For related structures, see: Ayyappan et al. (2001 ); Abu-Youssef (2005 ); Chen et al. (2001 , 2008 ); Lin et al. (2000 ); Liu et al. (2005 ); Madalan et al. (2005 ); Wang et al. (2002 ); Wasson & LaDuca (2007 ); Wu et al. (2003 ).

Experimental

Crystal data

[Cd₂(C₆H₄NO₂)₄(C₂H₈N₂)₂(H₂O)₂]·2H₂O
M_r = 905.18
Triclinic, $[P \overline 1]$
a = 7.678 (1) Å
b = 10.364 (1) Å
c = 11.984 (2) Å
α = 101.080 (1)°
β = 93.60 (1)°
γ = 109.63 (1)°
V = 873.1 (2) Å³
Z = 1
Mo Kα radiation
μ = 1.29 mm⁻¹
T = 294 (2) K
0.35 × 0.30 × 0.20 mm

Data collection

Siemens P4 diffractometer
Absorption correction: ψ scan (XEMP; Siemens, 1994 ) T_min = 0.652, T_max = 0.776
6118 measured reflections
5071 independent reflections
4491 reflections with I > 2σ(I)
R_int = 0.055
3 standard reflections every 97 reflections intensity decay: 2.0%

Refinement

R[F² > 2σ(F²)] = 0.030
wR(F²) = 0.076
S = 1.06
5071 reflections
245 parameters
21 restraints
H-atom parameters constrained
Δρ_max = 0.57 e Å⁻³
Δρ_min = −0.62 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1W—H1W⋯O4ⁱ	0.82	1.84	2.659 (2)	174
O1W—H2W⋯O2ⁱⁱ	0.84	1.93	2.762 (3)	169
O2W—H3W⋯O2Wⁱⁱⁱ	0.84	2.25	3.041 (10)	158
O2W—H4W⋯O3^iv	0.82	1.97	2.742 (5)	157
N3—H3A⋯O2	0.89	2.37	3.099 (3)	139
N3—H3B⋯O4^v	0.90	2.11	2.966 (3)	160
N3—H3C⋯O2	0.89	2.36	3.099 (3)	141
N3—H3D⋯O4^v	0.90	2.24	2.966 (3)	138
N4—H4A⋯O3ⁱ	0.91	2.16	3.054 (3)	169
N4—H4B⋯O2W	0.91	2.22	2.975 (4)	140
N4—H4C⋯O3ⁱ	0.92	2.26	3.054 (3)	145
N4—H4D⋯O2W	0.90	2.13	2.975 (4)	157
Symmetry codes: (i) x, y-1, z; (ii) x+1, y, z; (iii) -x, -y, -z+1; (iv) -x+1, -y+1, -z+1; (v) -x+1, -y+1, -z.

Data collection: XSCANS (Siemens, 1994); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997 ); software used to prepare material for publication: enCIFer (Allen et al., 2004 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808009756/zl2107sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808009756/zl2107Isup2.hkl

checkCIF report

Comment top

Several Cd^II coordination polymers that contain bridging 3-pyridylcarboxylate (nicotinate) ligands have been reported recently (Abu-Youssef, 2005; Evans & Lin, 2001; Chen, (2003); Clegg et al., 1995; Kang et al., 2007; Liang & Li, 2005; Lu & Kohler, 2002; Lu et al., 2007; Song et al., 2006; Xian et al. 2007; Zhang et al., 1996; Zhang et al., 2004). However, if the nicotinate anions are coordinated only as terminal ligands, the possibility of participating in a hydrogen-bonding network originates. As part of our efforts to investigate metal(II) complexes based on pyridine carboxylic acids, we report herein the crystal structure of the title compound, (I).

Figure 1 shows a representative ORTEP diagram for (I). The Cd centers are µ₂-bridged by two nicotinate ligands to form a twelve-membered (CdNC₃O)₂ ring with the Cd···Cdⁱ [symmetry code: (i) -x + 1, -y + 1, -z + 1] distance being 7.355 (1) Å. The two nicotinate ligands bridge two Cd centers through the pyridyl N atom and one of the carboxylate O atoms. The Cd²⁺ ion has a distorted octahedral coordination formed by the two pyridine N atoms of bridging [Cd–N1ⁱ = 2.349 (2) Å] and terminal [Cd–N2 = 2.406 (2) Å] nicotinate anions; the two N atoms of chelating 1,2-ethylenediamine ligands [Cd–N3 = 2.321 (2) Å and Cd–N4 = 2.345 (2) Å], and two O atoms in trans positions, one from the carboxylate group of a µ₂-bridging nicotinate ligand [Cd–O1 = 2.325 (2) Å] and one from the coordinated water molecule [Cd–O1W = 2.348 (2) Å].

The structure of (I) can be compared with two dimeric copper(II) complexes with a µ₂-bridging nicotinate ligand [Cu(µ₂-nic)(dien)]₂(nic)₂ (II) and [Cu(µ₂-nic)(dien)]₂(BF₄)₂.2MeOH (III) [dien is diethylenetriamine] (Chen et al., 2008). Both compounds (II-III) are dimeric complexes, where the nicotinate ligands are bridging two Cu centers to form similar twelve-membered (CuNC₃O)₂ rings (Table 2). On the other hand, the same (MNC₃O)₂ [M = Cu, Cd, Ni or Mn] rings are observed in some metal(II) nicotinate based coordination polymers, but the nicotinate ligands are µ₃-bridging ones. M···M distances and chromophores for dinuclear and polymeric complexes with twelve-membered (MNC₃O)₂ rings are compared in Table 2.

The hydrogen-bonding parameters of (I) are listed in Table 1. In the crystal structure, intermolecular O–H···O and N–H···O hydrogen-bonds (Table 1) link the molecules to form a three-dimensional network (Figures 2 and 3). One of the amine H atoms of the 1,2-ethylenediamine ligand forms an intramolecular hydrogen-bond [N3–H3A···O2 or N3–H3C···O2] and partipicates in creation of aan intramolecular metallocyclus with an S(6) pattern (Bernstein et al., 1995) (Figure 2). One O atom and one H atom of each of the uncoordinated water molecules, two amine groups of the 1,2-ethylenediamine ligands and one carboxylate O atom of each of the terminal nicotinate ligands are connected through hydrogen-bonds to rings with a graph set motif of R₆⁶(12) (Bernstein et al., 1995) [N4–H4B···O2W or N4–H4D···O2W; N4–H4A···O3ⁱⁱⁱ or N4–H4C···O3ⁱⁱⁱ; and O2W–H4W···O3ⁱ, symmetry codes: (i) -x + 1, -y + 1, -z + 1; (iii) x, y - 1, z] (Figure 2). The H atoms from the amine groups of the 1,2-ethylenediamine ligand and the H atoms from the coordinated water molecule are connected through hydrogen-bonds to the carboxylate O atoms of the terminal nicotinate ligands [N4–H4A···O3ⁱⁱⁱ or N4–H4C···O3ⁱⁱⁱ; O1W–H1W···O4ⁱⁱⁱ] and these groups create six-membered R₂²(8) rings (Bernstein et al., 1995) (Figure 2). The remaining hydrogen-bonds from the amine groups of the ethylendiamine ligands are connected to carboxylate O atoms of terminal nicotinate ligands of neighbouring complex molecules [N3–H3B···O4ⁱⁱ or N3–H3D···O4ⁱⁱ, symmetry codes: (ii) -x + 1, -y + 1, -z] (Figure 2). Further intermolecular hydrogen-bonds between uncoordinated water molecules [O2W–H3W···O2W^v, symmetry codes: (v) -x, -y, -z + 1], and between coordinated water molecules and carboxylate O atoms of bridging nicotinate ligands [O1W–H2W···O2^iv, symmetry codes: (iv) x + 1, y, z] are shown in Figure 3.

Additional interactions between the pyridine rigs of nicotinate ligands are π-π stacking interactions (Janiak, 2000) between the two adjacent pyridine rings of terminal nicotinate ligands [N2/C8—C12] (π_a-π_aⁱⁱ) (Figure 2), and between the two adjacent pyridine rings of bridging nicotinate ligands [N1/C2—C6] (π_b-π_b^vi) (Figure 3) [symmetry codes: (ii) -x + 1, -y + 1, -z; (vi) -x, -y + 1, -z - 1]. The centroid (C_g) distances C_g···C_g are 3.69 and 3.59 Å, respectively. The distances between parallel planes of the stacked pyridine rings are 3.43 and 3.53 Å, respectively.

Related literature top

For related literature, see: Bernstein et al. (1995); Chen (2003); Clegg et al. (1995); Evans & Lin (2001); Janiak (2000); Kang et al. (2007); Liang & Li (2005); Lu & Kohler (2002); Lu et al. (2007); Luo et al. (2004); Song et al. (2006); Xian et al. (2007); Zhang et al. (1996); Zhang et al. (2004). For related structures, see: Ayyappan et al. (2001); Abu-Youssef (2005); Chen et al. (2001, 2008); Lin et al. (2000); Liu et al. (2005); Madalan et al. (2005); Wang et al. (2002); Wasson & LaDuca (2007); Wu et al. (2003).

Experimental top

The title complex was formed in a methanolic solution (30 cm³) of Cd(nicotinate)₂.H₂O (1.25 mmol) by adding 1,2-ethylenediamine in the molar ratio of 1:1. The resulting solution was left to slowly evaporate at room temperature. Well shaped crystals, suitable for X-ray structure analysis were collected after a few days by filtration and finally dried in vacuo. Anal. Calc.: C, 37.14; H, 4.45; N, 12.37; Cd, 24.83; Found: C, 36.82; H, 4.53; N, 12.30; Cd, 24.65. Selected IR data (KBr) cm^-1: 1611 vs,br ν_as(COO^-); 1383 vs,br ν_s(COO^-); 643m δ(pyridine ring in-plane bending); 432m χ(pyridine ring out-of-plane bending).

Computing details top

Data collection: XSCANS (Siemens, 1994); cell refinement: XSCANS (Siemens, 1994); data reduction: XSCANS (Siemens, 1994); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: enCIFer (Allen et al., 2004).

Figures top

	Fig. 1. Perspective view of (I), with the atom numbering scheme. Thermal ellipsoids are drawn at the 30% probability level. Bonds in the minor disordered parts are drawn as open-dashed lines.
	Fig. 2. The hydrogen-bonds and π_a-π_a stacking interactions in the crystal packing of (I). Only the major disordered part is shown. [symmetry codes: (i) -x + 1, -y + 1, -z + 1; (ii) -x + 1, -y + 1, -z; (iii) x, y - 1, z]
	Fig. 3. The hydrogen-bonds and π_b-π_b stacking interactions in the crystal packing of (I). Only the major disordered part is shown. [symmetry codes: (iii) x, y - 1, z; (iv) x + 1, y, z; (v) -x, -y, -z + 1]

Di-µ-nicotinato-κ²N:O;κ²O:N-bis[aqua(ethylenediamine- κ²N,N')(nicotinato-κN)cadmium(II)] dihydrate top

Crystal data top

[Cd₂(C₆H₄NO₂)₄(C₂H₈N₂)₂(H₂O)₂]·2H₂O	Z = 1
M_r = 905.18	F(000) = 456
Triclinic, P1	D_x = 1.722 Mg m⁻³
Hall symbol: -P1	Mo Kα radiation, λ = 0.71073 Å
a = 7.678 (1) Å	Cell parameters from 25 reflections
b = 10.364 (1) Å	θ = 2.1–8.9°
c = 11.984 (2) Å	µ = 1.29 mm⁻¹
α = 101.08 (1)°	T = 294 K
β = 93.60 (1)°	Prism, colourless
γ = 109.63 (1)°	0.35 × 0.30 × 0.20 mm
V = 873.1 (2) Å³

Data collection top

Siemens P4 diffractometer	4491 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.055
Graphite monochromator	θ_max = 30.0°, θ_min = 1.8°
2θ/ω scans	h = −1→10
Absorption correction: ψ scan (XEMP; Siemens, 1994)	k = −14→13
T_min = 0.652, T_max = 0.776	l = −16→16
6118 measured reflections	3 standard reflections every 97 reflections
5071 independent reflections	intensity decay: 2.0%

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.030	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.076	H-atom parameters constrained
S = 1.06	w = 1/[σ²(F_o²) + (0.0307P)² + 0.1604P] where P = (F_o² + 2F_c²)/3
5071 reflections	(Δ/σ)_max = 0.001
245 parameters	Δρ_max = 0.57 e Å⁻³
21 restraints	Δρ_min = −0.62 e Å⁻³

Crystal data top

[Cd₂(C₆H₄NO₂)₄(C₂H₈N₂)₂(H₂O)₂]·2H₂O	γ = 109.63 (1)°
M_r = 905.18	V = 873.1 (2) Å³
Triclinic, P1	Z = 1
a = 7.678 (1) Å	Mo Kα radiation
b = 10.364 (1) Å	µ = 1.29 mm⁻¹
c = 11.984 (2) Å	T = 294 K
α = 101.08 (1)°	0.35 × 0.30 × 0.20 mm
β = 93.60 (1)°

Data collection top

Siemens P4 diffractometer	4491 reflections with I > 2σ(I)
Absorption correction: ψ scan (XEMP; Siemens, 1994)	R_int = 0.055
T_min = 0.652, T_max = 0.776	3 standard reflections every 97 reflections
6118 measured reflections	intensity decay: 2.0%
5071 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.030	21 restraints
wR(F²) = 0.076	H-atom parameters constrained
S = 1.06	Δρ_max = 0.57 e Å⁻³
5071 reflections	Δρ_min = −0.62 e Å⁻³
245 parameters

Special details top

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 > 2sigma(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 (Å²) top

	x	y	z	U_iso*/U_eq	Occ. (<1)
Cd1	0.50747 (2)	0.217937 (14)	0.263617 (13)	0.03264 (6)
O1	0.3261 (3)	0.3353 (2)	0.35364 (17)	0.0505 (5)
O1W	0.7358 (3)	0.13999 (17)	0.18352 (18)	0.0457 (4)
H1W	0.7166	0.0558	0.1631	0.069*
H2W	0.8505	0.1895	0.2005	0.069*
O2	0.1020 (3)	0.3222 (2)	0.21860 (16)	0.0471 (4)
O2W	0.1968 (6)	0.0994 (5)	0.4981 (3)	0.1256 (15)
H3W	0.1050	0.0314	0.5055	0.188*
H4W	0.2579	0.1496	0.5595	0.188*
O3	0.6053 (4)	0.8065 (2)	0.2856 (2)	0.0739 (8)
O4	0.6980 (4)	0.87012 (19)	0.12727 (19)	0.0619 (6)
N1	0.2917 (3)	0.6858 (2)	0.56161 (17)	0.0364 (4)
N2	0.6293 (3)	0.41008 (18)	0.17134 (17)	0.0353 (4)
N3	0.2678 (3)	0.0997 (2)	0.11238 (19)	0.0429 (4)
H3A	0.1697	0.1239	0.1265	0.051*	0.780 (10)
H3B	0.3071	0.1225	0.0476	0.051*	0.780 (10)
H3C	0.2002	0.1532	0.1062	0.051*	0.220 (10)
H3D	0.3192	0.0863	0.0479	0.051*	0.220 (10)
N4	0.3717 (3)	−0.0048 (2)	0.30277 (19)	0.0445 (5)
H4A	0.4522	−0.0522	0.2930	0.053*	0.780 (10)
H4B	0.3529	0.0051	0.3776	0.053*	0.780 (10)
H4C	0.4641	−0.0346	0.3276	0.053*	0.220 (10)
H4D	0.3025	0.0006	0.3600	0.053*	0.220 (10)
C1	0.2052 (3)	0.3777 (2)	0.3123 (2)	0.0347 (4)
C2	0.1904 (3)	0.5085 (2)	0.38534 (19)	0.0315 (4)
C3	0.2937 (3)	0.5680 (2)	0.4933 (2)	0.0357 (4)
H3	0.3691	0.5233	0.5199	0.043*
C4	0.1810 (4)	0.7494 (2)	0.5236 (2)	0.0412 (5)
H4	0.1777	0.8311	0.5702	0.049*
C5	0.0722 (4)	0.6972 (3)	0.4178 (2)	0.0468 (6)
H5	−0.0040	0.7429	0.3940	0.056*
C6	0.0771 (3)	0.5761 (3)	0.3470 (2)	0.0407 (5)
H6	0.0058	0.5405	0.2749	0.049*
C7	0.6597 (4)	0.7856 (2)	0.1908 (2)	0.0428 (5)
C8	0.6792 (3)	0.6441 (2)	0.1471 (2)	0.0326 (4)
C9	0.6207 (3)	0.5384 (2)	0.20765 (19)	0.0333 (4)
H9	0.5737	0.5576	0.2761	0.040*
C10	0.6977 (3)	0.3842 (2)	0.0733 (2)	0.0386 (5)
H10	0.7041	0.2955	0.0478	0.046*
C11	0.7595 (4)	0.4825 (3)	0.0076 (2)	0.0399 (5)
H11	0.8065	0.4605	−0.0603	0.048*
C12	0.7494 (3)	0.6147 (2)	0.0455 (2)	0.0358 (4)
H12	0.7895	0.6829	0.0030	0.043*
C13A	0.2200 (8)	−0.0529 (4)	0.1059 (4)	0.0548 (13)	0.780 (10)
H13A	0.3186	−0.0828	0.0767	0.066*	0.780 (10)
H13B	0.1052	−0.1059	0.0539	0.066*	0.780 (10)
C14A	0.1963 (8)	−0.0807 (5)	0.2237 (4)	0.0604 (14)	0.780 (10)
H14A	0.0978	−0.0504	0.2527	0.072*	0.780 (10)
H14B	0.1602	−0.1808	0.2193	0.072*	0.780 (10)
C13B	0.1473 (18)	−0.0289 (13)	0.1436 (17)	0.056 (4)	0.220 (10)
H13C	0.0625	−0.0923	0.0769	0.067*	0.220 (10)
H13D	0.0740	−0.0052	0.2019	0.067*	0.220 (10)
C14B	0.270 (2)	−0.0967 (12)	0.1881 (13)	0.052 (4)	0.220 (10)
H14C	0.3580	−0.1059	0.1354	0.062*	0.220 (10)
H14D	0.1959	−0.1898	0.1967	0.062*	0.220 (10)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cd1	0.04196 (9)	0.02134 (7)	0.03364 (8)	0.01255 (6)	0.00412 (6)	0.00197 (5)
O1	0.0542 (11)	0.0569 (11)	0.0438 (9)	0.0363 (9)	−0.0027 (8)	−0.0076 (8)
O1W	0.0458 (9)	0.0247 (7)	0.0671 (12)	0.0154 (7)	0.0149 (8)	0.0040 (7)
O2	0.0444 (9)	0.0463 (9)	0.0415 (9)	0.0158 (8)	−0.0034 (7)	−0.0076 (7)
O2W	0.162 (4)	0.189 (4)	0.075 (2)	0.125 (3)	0.040 (2)	0.022 (2)
O3	0.135 (2)	0.0523 (12)	0.0625 (14)	0.0592 (14)	0.0451 (15)	0.0202 (11)
O4	0.1147 (19)	0.0276 (8)	0.0537 (12)	0.0330 (10)	0.0270 (12)	0.0143 (8)
N1	0.0429 (10)	0.0330 (9)	0.0338 (9)	0.0176 (8)	0.0026 (7)	0.0023 (7)
N2	0.0440 (10)	0.0227 (7)	0.0409 (10)	0.0147 (7)	0.0038 (8)	0.0067 (7)
N3	0.0484 (11)	0.0411 (10)	0.0368 (10)	0.0151 (9)	0.0021 (8)	0.0062 (8)
N4	0.0578 (13)	0.0339 (9)	0.0417 (11)	0.0138 (9)	0.0093 (9)	0.0124 (8)
C1	0.0322 (10)	0.0333 (10)	0.0352 (10)	0.0108 (8)	0.0063 (8)	0.0012 (8)
C2	0.0308 (9)	0.0300 (9)	0.0341 (10)	0.0113 (8)	0.0082 (8)	0.0059 (8)
C3	0.0391 (11)	0.0335 (10)	0.0361 (10)	0.0182 (9)	0.0038 (8)	0.0026 (8)
C4	0.0532 (14)	0.0342 (11)	0.0413 (12)	0.0234 (10)	0.0066 (10)	0.0060 (9)
C5	0.0578 (15)	0.0456 (13)	0.0460 (13)	0.0309 (12)	0.0013 (11)	0.0102 (11)
C6	0.0422 (12)	0.0442 (12)	0.0375 (11)	0.0198 (10)	0.0008 (9)	0.0068 (9)
C7	0.0629 (15)	0.0264 (9)	0.0439 (12)	0.0223 (10)	0.0083 (11)	0.0071 (9)
C8	0.0362 (10)	0.0228 (8)	0.0394 (10)	0.0122 (7)	0.0018 (8)	0.0064 (7)
C9	0.0402 (11)	0.0248 (9)	0.0367 (10)	0.0141 (8)	0.0050 (8)	0.0066 (8)
C10	0.0504 (13)	0.0262 (9)	0.0410 (11)	0.0191 (9)	0.0041 (9)	0.0028 (8)
C11	0.0485 (13)	0.0355 (11)	0.0404 (11)	0.0207 (10)	0.0128 (9)	0.0065 (9)
C12	0.0399 (11)	0.0279 (9)	0.0406 (11)	0.0112 (8)	0.0087 (9)	0.0102 (8)
C13A	0.069 (3)	0.0353 (17)	0.0425 (19)	0.0009 (17)	−0.0001 (18)	0.0024 (14)
C14A	0.062 (3)	0.048 (2)	0.052 (2)	−0.007 (2)	0.006 (2)	0.0158 (19)
C13B	0.043 (7)	0.043 (7)	0.063 (10)	0.004 (5)	−0.002 (6)	−0.004 (6)
C14B	0.055 (8)	0.024 (5)	0.064 (9)	0.001 (5)	0.011 (6)	0.003 (5)

Geometric parameters (Å, º) top

Cd1—N3	2.321 (2)	N4—H4D	0.8980
Cd1—O1	2.325 (2)	C1—C2	1.509 (3)
Cd1—N4	2.344 (2)	C2—C3	1.385 (3)
Cd1—O1W	2.348 (2)	C2—C6	1.394 (3)
Cd1—N1ⁱ	2.349 (2)	C3—H3	0.9300
Cd1—N2	2.406 (2)	C4—C5	1.378 (4)
O1—C1	1.264 (3)	C4—H4	0.9300
O1W—H1W	0.8187	C5—C6	1.387 (3)
O1W—H2W	0.8450	C5—H5	0.9300
O2—C1	1.247 (3)	C6—H6	0.9300
O2W—H3W	0.8365	C7—C8	1.519 (3)
O2W—H4W	0.8232	C8—C12	1.385 (3)
O3—C7	1.240 (3)	C8—C9	1.395 (3)
O4—C7	1.243 (3)	C9—H9	0.9300
N1—C3	1.339 (3)	C10—C11	1.384 (3)
N1—C4	1.344 (3)	C10—H10	0.9300
N1—Cd1ⁱ	2.349 (2)	C11—C12	1.388 (3)
N2—C10	1.334 (3)	C11—H11	0.9300
N2—C9	1.343 (3)	C12—H12	0.9300
N3—C13B	1.477 (12)	C13A—C14A	1.504 (6)
N3—C13A	1.484 (4)	C13A—H13A	0.9700
N3—H3A	0.8860	C13A—H13B	0.9700
N3—H3B	0.8955	C14A—H14A	0.9700
N3—H3C	0.8870	C14A—H14B	0.9700
N3—H3D	0.8982	C13B—C14B	1.479 (15)
N4—C14A	1.474 (5)	C13B—H13C	0.9700
N4—C14B	1.507 (12)	C13B—H13D	0.9700
N4—H4A	0.9105	C14B—H14C	0.9700
N4—H4B	0.9088	C14B—H14D	0.9700
N4—H4C	0.9180

N3—Cd1—O1	90.64 (7)	O2—C1—C2	118.9 (2)
N3—Cd1—N4	76.38 (8)	O1—C1—C2	115.1 (2)
O1—Cd1—N4	100.83 (9)	C3—C2—C6	117.3 (2)
N3—Cd1—O1W	97.31 (8)	C3—C2—C1	120.63 (19)
O1—Cd1—O1W	169.36 (7)	C6—C2—C1	122.1 (2)
N4—Cd1—O1W	87.95 (7)	N1—C3—C2	124.0 (2)
N3—Cd1—N1ⁱ	168.76 (7)	N1—C3—H3	118.0
O1—Cd1—N1ⁱ	84.28 (7)	C2—C3—H3	118.0
N4—Cd1—N1ⁱ	94.70 (7)	N1—C4—C5	122.1 (2)
O1W—Cd1—N1ⁱ	89.07 (7)	N1—C4—H4	119.0
N3—Cd1—N2	91.32 (7)	C5—C4—H4	119.0
O1—Cd1—N2	88.34 (7)	C4—C5—C6	119.5 (2)
N4—Cd1—N2	164.61 (7)	C4—C5—H5	120.2
O1W—Cd1—N2	84.44 (7)	C6—C5—H5	120.2
N1ⁱ—Cd1—N2	98.52 (7)	C5—C6—C2	119.1 (2)
C1—O1—Cd1	130.80 (16)	C5—C6—H6	120.4
Cd1—O1W—H1W	120.5	C2—C6—H6	120.4
Cd1—O1W—H2W	121.2	O3—C7—O4	125.6 (2)
H1W—O1W—H2W	113.0	O3—C7—C8	117.7 (2)
H3W—O2W—H4W	113.8	O4—C7—C8	116.7 (2)
C3—N1—C4	118.0 (2)	C12—C8—C9	118.18 (19)
C3—N1—Cd1ⁱ	119.65 (15)	C12—C8—C7	121.6 (2)
C4—N1—Cd1ⁱ	122.28 (16)	C9—C8—C7	120.2 (2)
C10—N2—C9	117.98 (19)	N2—C9—C8	122.8 (2)
C10—N2—Cd1	117.60 (14)	N2—C9—H9	118.6
C9—N2—Cd1	124.23 (16)	C8—C9—H9	118.6
C13B—N3—Cd1	107.2 (6)	N2—C10—C11	123.4 (2)
C13A—N3—Cd1	107.0 (2)	N2—C10—H10	118.3
C13B—N3—H3A	80.3	C11—C10—H10	118.3
C13A—N3—H3A	109.8	C10—C11—C12	118.3 (2)
Cd1—N3—H3A	109.2	C10—C11—H11	120.8
C13B—N3—H3B	135.6	C12—C11—H11	120.8
C13A—N3—H3B	111.4	C8—C12—C11	119.4 (2)
Cd1—N3—H3B	109.0	C8—C12—H12	120.3
H3A—N3—H3B	110.3	C11—C12—H12	120.3
C13B—N3—H3C	107.7	N3—C13A—C14A	109.3 (4)
C13A—N3—H3C	133.5	N3—C13A—H13A	109.8
Cd1—N3—H3C	108.4	C14A—C13A—H13A	109.8
C13B—N3—H3D	115.9	N3—C13A—H13B	109.8
C13A—N3—H3D	86.8	C14A—C13A—H13B	109.8
Cd1—N3—H3D	108.1	H13A—C13A—H13B	108.3
H3C—N3—H3D	109.4	N4—C14A—C13A	110.5 (4)
C14A—N4—Cd1	108.3 (2)	N4—C14A—H14A	109.6
C14B—N4—Cd1	103.7 (6)	C13A—C14A—H14A	109.6
C14A—N4—H4A	110.7	N4—C14A—H14B	109.6
C14B—N4—H4A	85.4	C13A—C14A—H14B	109.6
Cd1—N4—H4A	109.4	H14A—C14A—H14B	108.1
C14A—N4—H4B	112.2	N3—C13B—C14B	107.7 (12)
C14B—N4—H4B	137.7	N3—C13B—H13C	110.2
Cd1—N4—H4B	109.4	C14B—C13B—H13C	110.2
H4A—N4—H4B	106.8	N3—C13B—H13D	110.2
C14A—N4—H4C	131.2	C14B—C13B—H13D	110.2
C14B—N4—H4C	110.1	H13C—C13B—H13D	108.5
Cd1—N4—H4C	109.3	C13B—C14B—N4	107.3 (12)
C14A—N4—H4D	88.0	C13B—C14B—H14C	110.3
C14B—N4—H4D	116.6	N4—C14B—H14C	110.3
Cd1—N4—H4D	109.8	C13B—C14B—H14D	110.3
H4C—N4—H4D	107.1	N4—C14B—H14D	110.3
O2—C1—O1	126.0 (2)	H14C—C14B—H14D	108.5

N3—Cd1—O1—C1	−33.5 (2)	O1—C1—C2—C3	−4.8 (3)
N4—Cd1—O1—C1	−109.7 (2)	O2—C1—C2—C6	−5.8 (3)
O1W—Cd1—O1—C1	105.0 (4)	O1—C1—C2—C6	173.7 (2)
N1ⁱ—Cd1—O1—C1	156.5 (2)	C4—N1—C3—C2	0.8 (4)
N2—Cd1—O1—C1	57.8 (2)	Cd1ⁱ—N1—C3—C2	−175.37 (17)
N3—Cd1—N2—C10	−65.68 (18)	C6—C2—C3—N1	−0.4 (4)
O1—Cd1—N2—C10	−156.28 (18)	C1—C2—C3—N1	178.1 (2)
N4—Cd1—N2—C10	−29.2 (4)	C3—N1—C4—C5	−0.2 (4)
O1W—Cd1—N2—C10	31.54 (18)	Cd1ⁱ—N1—C4—C5	175.8 (2)
N1ⁱ—Cd1—N2—C10	119.76 (17)	N1—C4—C5—C6	−0.6 (4)
N3—Cd1—N2—C9	109.32 (19)	C4—C5—C6—C2	0.9 (4)
O1—Cd1—N2—C9	18.72 (18)	C3—C2—C6—C5	−0.4 (4)
N4—Cd1—N2—C9	145.8 (3)	C1—C2—C6—C5	−179.0 (2)
O1W—Cd1—N2—C9	−153.46 (19)	O3—C7—C8—C12	−176.1 (3)
N1ⁱ—Cd1—N2—C9	−65.24 (19)	O4—C7—C8—C12	4.7 (4)
O1—Cd1—N3—C13B	−87.9 (8)	O3—C7—C8—C9	5.8 (4)
N4—Cd1—N3—C13B	13.1 (8)	O4—C7—C8—C9	−173.4 (3)
O1W—Cd1—N3—C13B	99.2 (8)	C10—N2—C9—C8	0.3 (3)
N1ⁱ—Cd1—N3—C13B	−25.0 (9)	Cd1—N2—C9—C8	−174.71 (16)
N2—Cd1—N3—C13B	−176.2 (8)	C12—C8—C9—N2	−0.2 (3)
O1—Cd1—N3—C13A	−121.2 (3)	C7—C8—C9—N2	178.0 (2)
N4—Cd1—N3—C13A	−20.2 (3)	C9—N2—C10—C11	−0.1 (4)
O1W—Cd1—N3—C13A	65.9 (3)	Cd1—N2—C10—C11	175.22 (19)
N1ⁱ—Cd1—N3—C13A	−58.3 (5)	N2—C10—C11—C12	−0.1 (4)
N2—Cd1—N3—C13A	150.4 (3)	C9—C8—C12—C11	−0.1 (3)
N3—Cd1—N4—C14A	−10.2 (3)	C7—C8—C12—C11	−178.2 (2)
O1—Cd1—N4—C14A	77.8 (3)	C10—C11—C12—C8	0.2 (4)
O1W—Cd1—N4—C14A	−108.2 (3)	C13B—N3—C13A—C14A	−46.9 (11)
N1ⁱ—Cd1—N4—C14A	162.9 (3)	Cd1—N3—C13A—C14A	48.5 (6)
N2—Cd1—N4—C14A	−47.9 (5)	C14B—N4—C14A—C13A	−46.1 (10)
N3—Cd1—N4—C14B	20.6 (7)	Cd1—N4—C14A—C13A	39.8 (6)
O1—Cd1—N4—C14B	108.7 (7)	N3—C13A—C14A—N4	−61.5 (8)
O1W—Cd1—N4—C14B	−77.4 (7)	C13A—N3—C13B—C14B	47.9 (10)
N1ⁱ—Cd1—N4—C14B	−166.3 (7)	Cd1—N3—C13B—C14B	−46.7 (16)
N2—Cd1—N4—C14B	−17.1 (8)	N3—C13B—C14B—N4	70 (2)
Cd1—O1—C1—O2	30.5 (4)	C14A—N4—C14B—C13B	49.7 (10)
Cd1—O1—C1—C2	−148.90 (17)	Cd1—N4—C14B—C13B	−53.2 (15)
O2—C1—C2—C3	175.7 (2)

Symmetry code: (i) −x+1, −y+1, −z+1.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1W—H1W···O4ⁱⁱ	0.82	1.84	2.659 (2)	174
O1W—H2W···O2ⁱⁱⁱ	0.84	1.93	2.762 (3)	169
O2W—H3W···O2W^iv	0.84	2.25	3.041 (10)	158
O2W—H4W···O3ⁱ	0.82	1.97	2.742 (5)	157
N3—H3A···O2	0.89	2.37	3.099 (3)	139
N3—H3B···O4^v	0.90	2.11	2.966 (3)	160
N3—H3C···O2	0.89	2.36	3.099 (3)	141
N3—H3D···O4^v	0.90	2.24	2.966 (3)	138
N4—H4A···O3ⁱⁱ	0.91	2.16	3.054 (3)	169
N4—H4B···O2W	0.91	2.22	2.975 (4)	140
N4—H4C···O3ⁱⁱ	0.92	2.26	3.054 (3)	145
N4—H4D···O2W	0.90	2.13	2.975 (4)	157

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

Experimental details

Crystal data
Chemical formula	[Cd₂(C₆H₄NO₂)₄(C₂H₈N₂)₂(H₂O)₂]·2H₂O
M_r	905.18
Crystal system, space group	Triclinic, P1
Temperature (K)	294
a, b, c (Å)	7.678 (1), 10.364 (1), 11.984 (2)
α, β, γ (°)	101.08 (1), 93.60 (1), 109.63 (1)
V (Å³)	873.1 (2)
Z	1
Radiation type	Mo Kα
µ (mm⁻¹)	1.29
Crystal size (mm)	0.35 × 0.30 × 0.20

Data collection
Diffractometer	Siemens P4 diffractometer
Absorption correction	ψ scan (XEMP; Siemens, 1994)
T_min, T_max	0.652, 0.776
No. of measured, independent and observed [I > 2σ(I)] reflections	6118, 5071, 4491
R_int	0.055
(sin θ/λ)_max (Å⁻¹)	0.703

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.030, 0.076, 1.06
No. of reflections	5071
No. of parameters	245
No. of restraints	21
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.57, −0.62

Computer programs: XSCANS (Siemens, 1994), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997), enCIFer (Allen et al., 2004).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1W—H1W···O4ⁱ	0.82	1.84	2.659 (2)	173.6
O1W—H2W···O2ⁱⁱ	0.84	1.93	2.762 (3)	169.0
O2W—H3W···O2Wⁱⁱⁱ	0.84	2.25	3.041 (10)	157.9
O2W—H4W···O3^iv	0.82	1.97	2.742 (5)	156.7
N3—H3A···O2	0.89	2.37	3.099 (3)	139.0
N3—H3B···O4^v	0.90	2.11	2.966 (3)	159.8
N3—H3C···O2	0.89	2.36	3.099 (3)	141.2
N3—H3D···O4^v	0.90	2.24	2.966 (3)	138.3
N4—H4A···O3ⁱ	0.91	2.16	3.054 (3)	168.8
N4—H4B···O2W	0.91	2.22	2.975 (4)	139.7
N4—H4C···O3ⁱ	0.92	2.26	3.054 (3)	145.1
N4—H4D···O2W	0.90	2.13	2.975 (4)	157.1

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

Table 2. Comparative M···M distances (Å) and chromophores for selected dinuclear and polymeric complexes with 12-membered (MNC₃O)₂ rings top

Compound	Bonding mode	M···M	Chromophore
I^a	µ₂-nic-κ²N:O	7.355 (1)	CdN₄O₂
II^b	µ₂-nic-κ²N:O	6.904 (2)	CuN₄O
III^c	µ₂-nic-κ²N:O	6.972 (2)	CuN₄O
IV^d	µ₃-nic-κ³N:O:O'	7.208 (1)	MnN₂O₄
V^e	µ₃-nic-κ³N:O:O'	7.304 (3)	CdN₂O₄
VI^f	µ₃-nic-κ³N:O:O'	6.736 (1)	CuN₃O₂
VII^g	µ₃-nic-κ³N:O:O'	6.680 (1)	CuN₃O₂
VIII^h	µ₃-nic-κ³N:O:O'	6.646 (2)	NiN₂O₄
IXⁱ	µ₃-nic-κ³N:O:O'	6.90 (1)	NiN₂O₄
X^j	µ₃-nic-κ³N:O:O'	6.622 (2)	NiN₂O₄
XI^k	µ₃-nic-κ³N:O:O'	7.324 (1)	MnN₂O₄
XII^l	µ₃-nic-κ³N:O:O'	6.890 (2)	NiN₂O₄
	µ₂-nic-κ²N:O	7.027 (2)	NiN₃O₃

(a) [Cd(µ₂-nic)(nic)(en)(H₂O)]₂.2H₂O (this work); (b) [Cu(µ₂-nic)(dien)]₂(nic)₂ (dien is diethylenetriamine) (Chen et al., 2008); (c) [Cu(µ₂-nic)(dien)]₂(BF₄)₂.2MeOH [dien is diethylenetriamine] (Chen et al., 2008); (d) [Mn₃(µ₃-nic)₄(µ₂-N₃)₂(H₂O)₂]_n (Chen et al., 2001); (e) [Cd₃(µ₃-nic)₄(µ₂-N₃)₂(H₂O)₂]_n (Abu-Youssef, 2005); (f) [Cu₂(µ₃-nic)₂(Me₂bipy)₂]_n.2nClO₄ [Me₂bipy is 4,4'-dimethyl-2,2'-bipyridine] (Madalan et al., 2005); (g) [Cu₂(µ₃-nic)₂(bipy)₂]_n.2nClO₄.2H₂O [bipy is 2,2'-bipyridine] (Madalan et al., 2005); (h) [Ni₄(µ₃-nic)₄(µ₂-nic)₄(µ₂-H₂O)₂]_n.2nEtOH.2nH₂O (Ayyappan et al., 2001); (i) [Ni₄(µ₃-nic)₄(µ₂-nic)₄(µ₂-H₂O)₂]_n (Wu et al., 2003); (j) [Ni₄(µ₃-nic)₄(µ₂-nic)₄(µ₂-H₂O)₂]_n.2nH₂O (Wasson & LaDuca, 2007); (k) [Mn(µ₃-nic)₂]_n (Lin et al., 2000; Wang et al., 2002); (l) [Ni₃(µ₃-nic)₂(µ₂-nic)₂(µ₂-N₃)₂(µ₂-Hnic)₂]_n (Liu et al., 2005).

Acknowledgements

We thank the Scientific Grant Agency of the Ministry of Education of the Slovak Republic and the Slovak Academy of Sciences (grant Nos. 1/4454/07 and 1/0353/08) for financial support.

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