Bis(2-propyl-1H-imidazol-3-ium) bis­(pyridine-2,6-dicarboxyl­ato-κ3O2,N,O6)cadmate(II)

Dong, G.-Y.; Liu, T.-F.; He, C.-H.; Deng, X.-C.; Shi, X.-G.

doi:10.1107/S1600536811024792

metal-organic compounds

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ISSN: 2056-9890

Volume 67| Part 7| July 2011| Page m1007

doi:10.1107/S1600536811024792

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Bis(2-propyl-1H-imidazol-3-ium) bis(pyridine-2,6-dicarboxylato-κ³O²,N,O⁶)cadmate(II)

Gui-Ying Dong,^a ^* Tong-Fei Liu,^a Cui-Hong He,^a Xiao-Chen Deng ^b and Xiao-Ge Shi ^b

^aCollege of Chemical Engineering, Hebei United University, Tangshan 063009, People's Republic of China, and ^bQian'an College, Hebei United University, Tangshan 063009, People's Republic of China
^*Correspondence e-mail: tsdgying@126.com

(Received 6 June 2011; accepted 23 June 2011; online 30 June 2011)

The title salt, (C₆H₁₁N₂)₂[Cd(C₇H₃NO₄)₂], displays a discrete mononuclear structure, in which the central Cd^II atom is six-coordinated in a distorted octahedral coordination geometry by two N and four O atoms from two different pyridine-2,6-dicarboxylate anions in an O²,N,O⁶-tridentate chelation mode. The crystal packing is stabilized by N—H⋯O hydrogen bonds and π–π interactions [centroid–centroid distance = 3.576 (5) Å].

Related literature

For background to and the biological activity of pyridine-2,6-dicarboxylic acid, see: Hay et al. (2003 ). For related complexes, see: Dong et al. (2006 ); Guerriero et al. (1987 ); Kjell et al. (1993 ); Abboud et al. (1998 ).

Experimental

Crystal data

(C₆H₁₁N₂)₂[Cd(C₇H₃NO₄)₂]
M_r = 664.95
Monoclinic, C 2/c
a = 19.928 (4) Å
b = 9.5038 (19) Å
c = 15.073 (3) Å
β = 109.90 (3)°
V = 2684.2 (11) Å³
Z = 4
Mo Kα radiation
μ = 0.88 mm⁻¹
T = 295 K
0.22 × 0.12 × 0.08 mm

Data collection

Bruker SMART CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ) T_min = 0.796, T_max = 0.808
11223 measured reflections
2364 independent reflections
2238 reflections with I > 2σ(I)
R_int = 0.034

Refinement

R[F² > 2σ(F²)] = 0.031
wR(F²) = 0.065
S = 1.19
2364 reflections
186 parameters
H-atom parameters constrained
Δρ_max = 0.26 e Å⁻³
Δρ_min = −0.46 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H2B⋯O2ⁱ	0.86	1.93	2.753 (3)	160
N3—H3B⋯O4ⁱⁱ	0.86	1.84	2.690 (3)	173
Symmetry codes: (i) $[-x+{\script{1\over 2}}, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (ii) $[x+{\script{1\over 2}}, y-{\script{1\over 2}}, z]$ .

Data collection: SMART (Bruker, 1998 ); cell refinement: SAINT (Bruker, 1998); data reduction: SAINT; 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: SHELXTL.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811024792/aa2014sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536811024792/aa2014Isup2.hkl

checkCIF report

Comment top

The pyridine-2,6-dicarboxylic (dipicolinic) acid is now recognized to be a major component of bacterial spores, which is used in a variety of processes as an enzyme inhibitor, plant preservative and food sanitizer (Hay et al. 2003). Pyridine-2,6-dicarboxylate has proved to be a versatile ligand with N,O-chelation and adopts diverse coordination modes (Guerriero et al., 1987; Kjell et al., 1993; Abboud et al., 1998; Dong et al.,2006). Recent efforts of our laboratory to synthesize coordination polymers with pyridine-2,6-dicarboxylic acid and 2-propylimidazole with transition metals resulted in the synthesis of the title complex (I).

In the title compound, the Cd^II is octahedrally coordinated by two tridentate dipicolinate ligands via their O and N atoms. In the crystal structure, adjacent molecules are linked via strong N—H···O hydrogen bonds into chains parallel to the b axis, see Fig. 2. Also there are π-π interactions between the centroids of adjacent pyridine rings. For Cg1 (the centroid of ring N1,C1—C5) and Cg1^a (ring N1^a,C1^a—C5^a) [symmetry code (a):-x,-y,-z + 1), the centroid–centroid distance is 3.576 (5)Å and the dihedral angle is 12.43 (3)°, this may further stabilize the structure.

Related literature top

For background to and the biological activity of pyridine-2,6-dicarboxylic acid, see: Hay et al. (2003). For related complexes, see: Dong et al. (2006); Guerriero et al. (1987); Kjell et al. (1993); Abboud et al. (1998).

Experimental top

A mixture of cadmium(II) nitrate tetrahydrate (308.49 mg, 1 mmol) was added to a slightly basic (pH > 8) solution of pyridine-2,6-dicarboxylic acid (334 mg, 2 mmol), followed by the addition of 2-propylimidazole (440 mg, 4 mmol) with stirring. The reaction mixture was filtered and the filtrate was allowed to stay at room temperature. Colourless prism-shaped crystals were obtained after one week (yield: 0.132 g, 20%). Analysis for C₂₆H₂₈CdN₆O₈ (%): calculated C 46.96, H 4.24,N 12.64; found C 46.85, H 4.13 N 12.57.

Computing details top

Data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 1998); data reduction: SAINT (Bruker, 1998); 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: SHELXTL (Sheldrick, 2008).

Figures top

	Fig. 1. Fig. 1. The molecular structure of (I), showing displacement ellipsoids at the 30% probability level. Symmetry code: (i) -x, y, 0.5 - z.
	Fig. 2. A partial packing diagram of the title compound. Hydrogen bonds are shown as dashed lines and H atoms not involved in hydrogen bonding are omitted.

Bis(2-propyl-1H-imidazol-3-ium) bis(pyridine-2,6-dicarboxylato-κ³O²,N,O⁶)cadmate(II) top

Crystal data top

(C₆H₁₁N₂)₂[Cd(C₇H₃NO₄)₂]	F(000) = 1352
M_r = 664.95	D_x = 1.645 Mg m⁻³
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 5638 reflections
a = 19.928 (4) Å	θ = 22.4–4.6°
b = 9.5038 (19) Å	µ = 0.88 mm⁻¹
c = 15.073 (3) Å	T = 295 K
β = 109.90 (3)°	Prism, colourless
V = 2684.2 (11) Å³	0.22 × 0.12 × 0.08 mm
Z = 4

Data collection top

Bruker SMART CCD area-detector diffractometer	2364 independent reflections
Radiation source: fine–focus sealed tube	2238 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.034
ϕ and ω scans	θ_max = 25.0°, θ_min = 3.5°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −23→23
T_min = 0.796, T_max = 0.808	k = −11→11
11223 measured reflections	l = −17→17

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)] = 0.031	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.065	H-atom parameters constrained
S = 1.19	w = 1/[σ²(F_o²) + (0.0218P)² + 4.3339P] where P = (F_o² + 2F_c²)/3
2364 reflections	(Δ/σ)_max < 0.001
186 parameters	Δρ_max = 0.26 e Å⁻³
0 restraints	Δρ_min = −0.46 e Å⁻³

Crystal data top

(C₆H₁₁N₂)₂[Cd(C₇H₃NO₄)₂]	V = 2684.2 (11) Å³
M_r = 664.95	Z = 4
Monoclinic, C2/c	Mo Kα radiation
a = 19.928 (4) Å	µ = 0.88 mm⁻¹
b = 9.5038 (19) Å	T = 295 K
c = 15.073 (3) Å	0.22 × 0.12 × 0.08 mm
β = 109.90 (3)°

Data collection top

Bruker SMART CCD area-detector diffractometer	2364 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	2238 reflections with I > 2σ(I)
T_min = 0.796, T_max = 0.808	R_int = 0.034
11223 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.031	0 restraints
wR(F²) = 0.065	H-atom parameters constrained
S = 1.19	Δρ_max = 0.26 e Å⁻³
2364 reflections	Δρ_min = −0.46 e Å⁻³
186 parameters

Special details top

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 (Å²) top

	x	y	z	U_iso*/U_eq
Cd1	0.0000	0.07339 (3)	0.2500	0.03025 (11)
O1	0.09384 (11)	−0.0821 (2)	0.31049 (13)	0.0428 (5)
C7	0.13072 (14)	−0.0697 (3)	0.39623 (19)	0.0301 (6)
N1	0.04450 (10)	0.0993 (2)	0.40666 (14)	0.0221 (5)
O3	−0.06932 (10)	0.2362 (2)	0.29862 (13)	0.0400 (5)
O2	0.18879 (10)	−0.1286 (2)	0.43686 (14)	0.0413 (5)
O4	−0.07871 (12)	0.3529 (3)	0.42064 (15)	0.0513 (6)
C6	−0.05008 (14)	0.2656 (3)	0.3843 (2)	0.0309 (6)
C5	0.10172 (13)	0.0254 (3)	0.45517 (17)	0.0228 (5)
C1	0.01417 (13)	0.1878 (3)	0.44944 (18)	0.0243 (6)
C4	0.13092 (14)	0.0374 (3)	0.55192 (18)	0.0298 (6)
H4A	0.1713	−0.0139	0.5856	0.036*
C3	0.09920 (15)	0.1269 (3)	0.59761 (18)	0.0349 (7)
H3A	0.1173	0.1349	0.6630	0.042*
C2	0.04064 (14)	0.2043 (3)	0.54622 (18)	0.0321 (6)
H2A	0.0193	0.2667	0.5760	0.039*
N3	0.33043 (12)	0.0315 (2)	0.29967 (17)	0.0340 (6)
H3B	0.3571	−0.0311	0.3360	0.041*
C9	0.24342 (15)	0.1779 (3)	0.2381 (2)	0.0357 (7)
H9A	0.2019	0.2307	0.2254	0.043*
N2	0.29048 (11)	0.1827 (2)	0.18995 (16)	0.0313 (5)
H2B	0.2866	0.2357	0.1422	0.038*
C10	0.26839 (15)	0.0829 (3)	0.3068 (2)	0.0379 (7)
H10A	0.2476	0.0569	0.3511	0.045*
C8	0.34294 (14)	0.0927 (3)	0.2285 (2)	0.0316 (6)
C11	0.40311 (17)	0.0637 (4)	0.1952 (3)	0.0531 (9)
H11A	0.4345	−0.0051	0.2365	0.064*
H11B	0.4303	0.1495	0.1986	0.064*
C12	0.3781 (3)	0.0082 (5)	0.0936 (3)	0.0786 (14)
H12A	0.3508	0.0811	0.0517	0.094*
H12B	0.4196	−0.0118	0.0760	0.094*
C13	0.3335 (2)	−0.1215 (5)	0.0797 (3)	0.0729 (13)
H13A	0.3195	−0.1505	0.0149	0.109*
H13B	0.2917	−0.1021	0.0956	0.109*
H13C	0.3605	−0.1951	0.1195	0.109*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cd1	0.03459 (18)	0.03409 (18)	0.01739 (15)	0.000	0.00275 (11)	0.000
O1	0.0528 (13)	0.0463 (12)	0.0258 (11)	0.0206 (11)	0.0090 (9)	−0.0040 (9)
C7	0.0329 (15)	0.0278 (14)	0.0306 (15)	0.0010 (13)	0.0123 (12)	0.0042 (12)
N1	0.0216 (11)	0.0243 (12)	0.0198 (11)	−0.0003 (9)	0.0062 (9)	0.0008 (9)
O3	0.0346 (11)	0.0486 (13)	0.0298 (11)	0.0154 (10)	0.0019 (9)	0.0016 (9)
O2	0.0328 (11)	0.0433 (12)	0.0431 (12)	0.0159 (10)	0.0071 (9)	−0.0023 (10)
O4	0.0512 (14)	0.0585 (15)	0.0436 (13)	0.0309 (12)	0.0154 (11)	−0.0012 (11)
C6	0.0260 (14)	0.0309 (15)	0.0352 (16)	0.0036 (12)	0.0095 (12)	0.0034 (13)
C5	0.0215 (13)	0.0229 (13)	0.0233 (13)	−0.0009 (10)	0.0066 (10)	0.0028 (10)
C1	0.0243 (13)	0.0244 (13)	0.0255 (13)	0.0000 (11)	0.0101 (11)	−0.0002 (11)
C4	0.0261 (14)	0.0337 (16)	0.0245 (14)	0.0010 (12)	0.0021 (11)	0.0051 (12)
C3	0.0371 (16)	0.0478 (18)	0.0173 (13)	−0.0029 (14)	0.0062 (12)	−0.0017 (12)
C2	0.0349 (16)	0.0370 (17)	0.0268 (14)	−0.0008 (13)	0.0136 (12)	−0.0059 (12)
N3	0.0331 (13)	0.0281 (13)	0.0395 (14)	0.0027 (10)	0.0107 (11)	0.0019 (11)
C9	0.0265 (14)	0.0336 (16)	0.0462 (18)	0.0023 (12)	0.0112 (13)	−0.0047 (14)
N2	0.0296 (12)	0.0268 (12)	0.0373 (13)	−0.0007 (10)	0.0114 (10)	0.0020 (10)
C10	0.0362 (16)	0.0394 (17)	0.0421 (17)	−0.0022 (14)	0.0186 (13)	−0.0046 (15)
C8	0.0252 (14)	0.0254 (15)	0.0439 (17)	−0.0039 (12)	0.0115 (12)	−0.0034 (13)
C11	0.0419 (18)	0.0431 (19)	0.087 (3)	0.0057 (16)	0.0383 (19)	0.0133 (19)
C12	0.111 (4)	0.076 (3)	0.081 (3)	0.046 (3)	0.075 (3)	0.034 (2)
C13	0.092 (3)	0.076 (3)	0.048 (2)	0.037 (3)	0.021 (2)	−0.006 (2)

Geometric parameters (Å, º) top

Cd1—N1	2.235 (2)	C2—H2A	0.9300
Cd1—N1ⁱ	2.235 (2)	N3—C8	1.316 (4)
Cd1—O1	2.313 (2)	N3—C10	1.368 (4)
Cd1—O1ⁱ	2.313 (2)	N3—H3B	0.8600
Cd1—O3ⁱ	2.351 (2)	C9—C10	1.336 (4)
Cd1—O3	2.351 (2)	C9—N2	1.368 (4)
O1—C7	1.256 (3)	C9—H9A	0.9300
C7—O2	1.243 (3)	N2—C8	1.323 (3)
C7—C5	1.513 (4)	N2—H2B	0.8600
N1—C1	1.324 (3)	C10—H10A	0.9300
N1—C5	1.326 (3)	C8—C11	1.475 (4)
O3—C6	1.247 (3)	C11—C12	1.534 (6)
O4—C6	1.236 (3)	C11—H11A	0.9700
C6—C1	1.515 (4)	C11—H11B	0.9700
C5—C4	1.379 (4)	C12—C13	1.492 (6)
C1—C2	1.381 (4)	C12—H12A	0.9700
C4—C3	1.376 (4)	C12—H12B	0.9700
C4—H4A	0.9300	C13—H13A	0.9600
C3—C2	1.374 (4)	C13—H13B	0.9600
C3—H3A	0.9300	C13—H13C	0.9600

N1—Cd1—N1ⁱ	167.37 (11)	C2—C3—H3A	120.2
N1—Cd1—O1	71.16 (7)	C3—C2—C1	118.7 (3)
N1ⁱ—Cd1—O1	117.61 (7)	C3—C2—H2A	120.6
N1—Cd1—O1ⁱ	117.61 (7)	C1—C2—H2A	120.6
N1ⁱ—Cd1—O1ⁱ	71.16 (7)	C8—N3—C10	109.5 (2)
O1—Cd1—O1ⁱ	100.59 (11)	C8—N3—H3B	125.3
N1—Cd1—O3ⁱ	101.12 (7)	C10—N3—H3B	125.3
N1ⁱ—Cd1—O3ⁱ	70.27 (7)	C10—C9—N2	107.0 (3)
O1—Cd1—O3ⁱ	93.52 (8)	C10—C9—H9A	126.5
O1ⁱ—Cd1—O3ⁱ	141.21 (7)	N2—C9—H9A	126.5
N1—Cd1—O3	70.27 (7)	C8—N2—C9	109.1 (2)
N1ⁱ—Cd1—O3	101.12 (7)	C8—N2—H2B	125.5
O1—Cd1—O3	141.21 (7)	C9—N2—H2B	125.5
O1ⁱ—Cd1—O3	93.52 (8)	C9—C10—N3	106.7 (3)
O3ⁱ—Cd1—O3	97.69 (11)	C9—C10—H10A	126.6
C7—O1—Cd1	117.19 (17)	N3—C10—H10A	126.6
O2—C7—O1	125.8 (3)	N3—C8—N2	107.7 (2)
O2—C7—C5	117.2 (2)	N3—C8—C11	126.6 (3)
O1—C7—C5	117.0 (2)	N2—C8—C11	125.7 (3)
C1—N1—C5	121.1 (2)	C8—C11—C12	112.3 (3)
C1—N1—Cd1	120.09 (16)	C8—C11—H11A	109.2
C5—N1—Cd1	118.80 (16)	C12—C11—H11A	109.2
C6—O3—Cd1	117.65 (17)	C8—C11—H11B	109.2
O4—C6—O3	125.7 (3)	C12—C11—H11B	109.2
O4—C6—C1	117.2 (2)	H11A—C11—H11B	107.9
O3—C6—C1	117.1 (2)	C13—C12—C11	113.6 (3)
N1—C5—C4	120.9 (2)	C13—C12—H12A	108.9
N1—C5—C7	114.9 (2)	C11—C12—H12A	108.9
C4—C5—C7	124.2 (2)	C13—C12—H12B	108.9
N1—C1—C2	120.9 (2)	C11—C12—H12B	108.9
N1—C1—C6	114.8 (2)	H12A—C12—H12B	107.7
C2—C1—C6	124.3 (2)	C12—C13—H13A	109.5
C3—C4—C5	118.7 (2)	C12—C13—H13B	109.5
C3—C4—H4A	120.7	H13A—C13—H13B	109.5
C5—C4—H4A	120.7	C12—C13—H13C	109.5
C4—C3—C2	119.7 (2)	H13A—C13—H13C	109.5
C4—C3—H3A	120.2	H13B—C13—H13C	109.5

Symmetry code: (i) −x, y, −z+1/2.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2B···O2ⁱⁱ	0.86	1.93	2.753 (3)	160
N3—H3B···O4ⁱⁱⁱ	0.86	1.84	2.690 (3)	173

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

Experimental details

Crystal data
Chemical formula	(C₆H₁₁N₂)₂[Cd(C₇H₃NO₄)₂]
M_r	664.95
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	295
a, b, c (Å)	19.928 (4), 9.5038 (19), 15.073 (3)
β (°)	109.90 (3)
V (Å³)	2684.2 (11)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.88
Crystal size (mm)	0.22 × 0.12 × 0.08

Data collection
Diffractometer	Bruker SMART CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.796, 0.808
No. of measured, independent and observed [I > 2σ(I)] reflections	11223, 2364, 2238
R_int	0.034
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.031, 0.065, 1.19
No. of reflections	2364
No. of parameters	186
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.26, −0.46

Computer programs: SMART (Bruker, 1998), SAINT (Bruker, 1998), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2B···O2ⁱ	0.86	1.93	2.753 (3)	160
N3—H3B···O4ⁱⁱ	0.86	1.84	2.690 (3)	173

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

Acknowledgements

The authors thank Hebei United University for supporting this work.

References

Abboud, K. A., Xu, C. & Drago, R. S. (1998). Acta Cryst. C54, 1270–1273. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
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