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The title compound, [Cd(NO3)2(C9H12N4)2]n, has a one-dimensional double-bridged chain polymer structure with a 16-membered macrometallacyclic tetra­gonal structural motif. The CdII ion occupies a crystallographic inversion centre and is coordinated by four equatorial N atoms from four distinct bis­(2-methyl­imidazol-1-yl)methane ligands and two apical nitrate O atoms to form a slightly distorted octa­hedral coordination geometry.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270107043454/sf3054sup1.cif
Contains datablocks I, 070626

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270107043454/sf3054Isup2.hkl
Contains datablock I

CCDC reference: 665489

Comment top

Coordination polymers have attracted a great deal of attention because of their intriguing structural properties and potential applications in magnetism, electrical conductivity, ion exchange, separation and catalysis (Carlucci et al., 2003; Moulton & Zaworotko, 2001). Studies in this field have been focused on the design and construction of novel coordination frameworks and on the examination of the relationships between their structures and properties. Many coordination polymers with diverse architectures, such as linear or zigzag chains, helices, honeycombs, square grids, ladders, brick walls, and interwoven diamondoids, have been developed extensively (Bünzli & Piguet, 2002; Sharma & Rogers, 1999). More recently, flexible components, both ligands and metals, have been employed as versatile building blocks for coordination polymer construction, allowing access to topologies that are often unattainable by using more rigid components (Jung et al., 2002). Bis(2-methylimidazol-1-yl)methane (2-mBIM) is a bis-imidazole ligand connected by a flexible methylene linker. We have reported an interesting infinite one-dimensional catenane polymer formed by the addition of a solution of 2-mBIM to AgNO3 (Jin et al., 2006). We report here the interesting solid-state structure of a novel one-dimensional double-bridged chain polymer structure, (I), with a 16-membered macrometallacyclic tetragonal structural motif formed, by the addition of a solution of 2-mBIM to Cd(NO3)2.

As revealed by single-crystal X-ray diffraction analysis, each CdII cation occupies a crystallographic inversion centre and is coordinated by four N atoms from four distinct 2-mBIM ligands and two O atoms from two NO3 anions to form a slightly distorted octahedral geometry about the cadmium center. The four N donor atoms of the 2-mBIM ligands lie in the equatorial plane and the two coordinated NO3 anions in the apical positions (Fig. 1). Selected N—Cd—N and N—Cd—O bond angles are given in Table 1. The Cd1—N2 and Cd1—N5ii distances [see Table 1 for values and symmetry code] are within the range expected for such ligating bonds (Kasai et al., 2000). It is noteworthy that the nitrate anion, a monodentate ligand, has a Cd1—O1 distance that is slightly shorter than those reported for similar structures (Wang et al., 2000). The distances between Cd1 and O2 and between Cd1 and O3 are 3.319 (1) and 4.374 (2) Å, respectively.

Each pair of neighboring CdII centers is bridged by two 2-mBIM ligands to form a 16-membered macrometallacyclic tetragonal-shaped structural motif with a Cd···Cd separation of 9.654 Å. Each 2-mBIM ligand is coordinated to two CdII cations and acts as a bridge ligand to form a one-dimensional double-bridged chain polymer structure that runs along the [011] direction. The conformation of the 2-mBIM ligand in (I) is considerably different from that of free 2-mBIM (Jin & Gong, 2005), since the two methyl groups at the 2-position of the coordinated ligand point in the same direction (see Fig. 1). Each pair of 2-mBIM ligands in the same 16-membered metallacycle is centrosymmetric. The dihedral angle between the two imidazole rings of the same 2-mBIM ligand is 59.6°. Significant ππ contacts [the shortest N···N distance is 3.707 (2) Å] and weak C—H···O interactions between adjacent one-dimensional double-bridged chain polymers are present. Although similar one-dimensional double-bridged chain polymer structures have been documented for bipyridine ligands (Dong et al., 2000), coordination polymer structures containing Cd(NO3)2 and imidazole ligands are still quite rare.

Related literature top

For related literature, see: Bünzli & Piguet (2002); Carlucci et al. (2003); Dong et al. (2000); Jin & Gong (2005); Jin et al. (2006); Jung et al. (2002); Kasai et al. (2000); Moulton & Zaworotko (2001); Sharma & Rogers (1999); Wang et al. (2000).

Experimental top

A methanol solution (5 ml) of 2-mBIM (88 mg, 0.5 mmol) was diffused slowly into an aqueous solution (5 ml) of Cd(NO3)2·4H2O (154 mg, 0.5 mmol) in a test tube. Colorless crystals of [Cd(2-mBIM)2(NO3)2]n were formed at the solvent interface after two weeks with 84% yield.

Refinement top

H atoms were positioned geometrically at distances of 0.93 (CH), 0.97 (CH2) and 0.96 Å (CH3) from the parent C atoms; a riding model was used during the refinement process. The Uiso(H) values were constrained to be 1.2Ueq of the carrier atom, except for methyl H atoms, which were constrained to 1.5Ueq of the C atom.

Computing details top

Data collection: SMART (Bruker, 2001); cell refinement: SAINT-Plus (Bruker, 2001); data reduction: SAINT-Plus (Bruker, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 2001); software used to prepare material for publication: SHELXTL (Bruker, 2001).

Figures top
[Figure 1] Fig. 1. The structure of (I), showing the atom numbering. Displacement ellipsoids are drawn at the 50% probability level. H atoms have been omitted for clarity. [Symmetry codes: (i) −x + 1, −y, −z + 2; (ii) x, y − 1, z + 1; (iii) −x + 1, −y + 1, −z + 1.]
Poly[[bis-µ-3, 3'-bis(2-methylimidazol-1-yl)methyl]dinitratocadmium(II)] top
Crystal data top
[Cd(C9H12N4)2(NO3)2]V = 568.51 (11) Å3
Mr = 588.87Z = 1
Triclinic, P1F(000) = 298
Hall symbol: -P 1Dx = 1.720 Mg m3
a = 7.9252 (9) ÅMo Kα radiation, λ = 0.71073 Å
b = 9.2783 (10) Åθ = 2.5–28.0°
c = 9.4118 (10) ŵ = 1.02 mm1
α = 62.192 (2)°T = 298 K
β = 73.725 (2)°Block, colorless
γ = 69.787 (2)°0.32 × 0.26 × 0.24 mm
Data collection top
Bruker SMART APEX CCD area-detector
diffractometer
2229 independent reflections
Radiation source: sealed tube2168 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.060
phi and ω scansθmax = 26.0°, θmin = 2.5°
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
h = 99
Tmin = 0.74, Tmax = 0.78k = 1111
5982 measured reflectionsl = 1111
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.031Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.068H-atom parameters constrained
S = 1.07 w = 1/[σ2(Fo2) + (0.03P)2 + 0.33P]
where P = (Fo2 + 2Fc2)/3
2229 reflections(Δ/σ)max < 0.001
162 parametersΔρmax = 0.77 e Å3
0 restraintsΔρmin = 0.44 e Å3
Crystal data top
[Cd(C9H12N4)2(NO3)2]γ = 69.787 (2)°
Mr = 588.87V = 568.51 (11) Å3
Triclinic, P1Z = 1
a = 7.9252 (9) ÅMo Kα radiation
b = 9.2783 (10) ŵ = 1.02 mm1
c = 9.4118 (10) ÅT = 298 K
α = 62.192 (2)°0.32 × 0.26 × 0.24 mm
β = 73.725 (2)°
Data collection top
Bruker SMART APEX CCD area-detector
diffractometer
2229 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
2168 reflections with I > 2σ(I)
Tmin = 0.74, Tmax = 0.78Rint = 0.060
5982 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0310 restraints
wR(F2) = 0.068H-atom parameters constrained
S = 1.07Δρmax = 0.77 e Å3
2229 reflectionsΔρmin = 0.44 e Å3
162 parameters
Special details top

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 (Å2) top
xyzUiso*/Ueq
C10.2778 (4)0.1098 (4)0.7023 (3)0.0344 (6)
H10.18420.06760.77960.041*
C20.2821 (4)0.1729 (4)0.5412 (3)0.0345 (6)
H20.19470.18150.48720.041*
C30.5294 (4)0.1859 (3)0.5945 (3)0.0279 (6)
C40.7036 (4)0.2250 (4)0.5687 (3)0.0417 (7)
H4A0.68640.34490.52100.063*
H4B0.79100.17830.49730.063*
H4C0.74680.17710.67090.063*
C50.5099 (4)0.2867 (3)0.2980 (3)0.0291 (6)
H5A0.64170.25690.28340.035*
H5B0.47320.23270.24890.035*
C60.2721 (4)0.5508 (4)0.1735 (3)0.0334 (6)
H60.17660.50240.19850.040*
C70.2695 (4)0.7150 (4)0.0902 (3)0.0340 (6)
H70.16930.80060.04810.041*
C80.5413 (4)0.5863 (3)0.1520 (3)0.0288 (6)
C90.7341 (4)0.5483 (4)0.1659 (4)0.0417 (7)
H9A0.79190.62450.06990.063*
H9B0.79330.43470.17790.063*
H9C0.74270.56110.25890.063*
Cd10.50000.00001.00000.02545 (11)
N10.8951 (3)0.1401 (3)0.8239 (3)0.0319 (5)
N20.4318 (3)0.1167 (3)0.7363 (3)0.0307 (5)
N30.4417 (3)0.2223 (3)0.4716 (2)0.0272 (5)
N40.4444 (3)0.4688 (3)0.2142 (3)0.0275 (5)
N50.4377 (3)0.7378 (3)0.0765 (3)0.0301 (5)
O10.8240 (3)0.0798 (3)0.9281 (2)0.0377 (5)
O20.8068 (4)0.2008 (3)0.7872 (3)0.0591 (7)
O31.0513 (3)0.1352 (4)0.7587 (3)0.0628 (7)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0380 (16)0.0372 (16)0.0284 (14)0.0174 (13)0.0005 (12)0.0105 (13)
C20.0368 (16)0.0404 (16)0.0303 (14)0.0177 (13)0.0076 (12)0.0107 (13)
C30.0337 (14)0.0253 (13)0.0220 (13)0.0071 (11)0.0045 (11)0.0075 (11)
C40.0423 (17)0.058 (2)0.0244 (14)0.0219 (15)0.0038 (12)0.0111 (14)
C50.0389 (15)0.0267 (13)0.0199 (12)0.0094 (11)0.0029 (11)0.0080 (11)
C60.0347 (15)0.0341 (15)0.0320 (15)0.0131 (12)0.0075 (12)0.0096 (12)
C70.0373 (16)0.0321 (15)0.0323 (15)0.0072 (12)0.0104 (12)0.0112 (12)
C80.0356 (15)0.0292 (14)0.0212 (12)0.0120 (11)0.0015 (11)0.0088 (11)
C90.0380 (17)0.0326 (16)0.0462 (18)0.0129 (13)0.0095 (14)0.0047 (14)
Cd10.03127 (17)0.02535 (16)0.01893 (15)0.00968 (11)0.00312 (10)0.00696 (11)
N10.0322 (13)0.0297 (12)0.0320 (12)0.0089 (10)0.0036 (10)0.0109 (10)
N20.0370 (13)0.0326 (12)0.0209 (11)0.0132 (10)0.0034 (9)0.0070 (10)
N30.0356 (12)0.0267 (11)0.0191 (10)0.0108 (9)0.0043 (9)0.0069 (9)
N40.0344 (12)0.0246 (11)0.0223 (11)0.0092 (9)0.0049 (9)0.0070 (9)
N50.0359 (13)0.0280 (12)0.0261 (11)0.0103 (10)0.0051 (9)0.0090 (10)
O10.0420 (12)0.0396 (11)0.0323 (11)0.0080 (9)0.0005 (9)0.0197 (9)
O20.0722 (17)0.0774 (18)0.0518 (14)0.0424 (15)0.0104 (12)0.0287 (14)
O30.0323 (13)0.0845 (19)0.0821 (19)0.0163 (12)0.0132 (12)0.0534 (17)
Geometric parameters (Å, º) top
C1—C21.341 (4)C7—N51.383 (4)
C1—N21.374 (4)C7—H70.9300
C1—H10.9300C8—N51.324 (3)
C2—N31.377 (3)C8—N41.361 (3)
C2—H20.9300C8—C91.474 (4)
C3—N21.326 (3)C9—H9A0.9600
C3—N31.362 (3)C9—H9B0.9600
C3—C41.474 (4)C9—H9C0.9600
C4—H4A0.9600Cd1—N2i2.338 (2)
C4—H4B0.9600Cd1—N22.338 (2)
C4—H4C0.9600Cd1—N5ii2.383 (2)
C5—N41.458 (3)Cd1—N5iii2.383 (2)
C5—N31.462 (3)Cd1—O1i2.404 (2)
C5—H5A0.9700Cd1—O12.404 (2)
C5—H5B0.9700N1—O31.224 (3)
C6—C71.345 (4)N1—O21.232 (3)
C6—N41.376 (4)N1—O11.255 (3)
C6—H60.9300N5—Cd1iv2.383 (2)
C2—C1—N2110.1 (2)H9A—C9—H9C109.5
C2—C1—H1125.0H9B—C9—H9C109.5
N2—C1—H1125.0N2i—Cd1—N2180.0
C1—C2—N3106.3 (2)N2i—Cd1—N5ii85.17 (8)
C1—C2—H2126.9N2—Cd1—N5ii94.83 (8)
N3—C2—H2126.9N2i—Cd1—N5iii94.83 (8)
N2—C3—N3109.8 (2)N2—Cd1—N5iii85.17 (8)
N2—C3—C4126.4 (2)N5ii—Cd1—N5iii180.0
N3—C3—C4123.7 (2)N2i—Cd1—O1i95.91 (7)
C3—C4—H4A109.5N2—Cd1—O1i84.09 (7)
C3—C4—H4B109.5N5ii—Cd1—O1i81.43 (7)
H4A—C4—H4B109.5N5iii—Cd1—O1i98.57 (7)
C3—C4—H4C109.5N2i—Cd1—O184.09 (7)
H4A—C4—H4C109.5N2—Cd1—O195.91 (7)
H4B—C4—H4C109.5N5ii—Cd1—O198.57 (7)
N4—C5—N3113.1 (2)N5iii—Cd1—O181.43 (7)
N4—C5—H5A109.0O1i—Cd1—O1180.0
N3—C5—H5A109.0O3—N1—O2121.0 (3)
N4—C5—H5B109.0O3—N1—O1119.1 (2)
N3—C5—H5B109.0O2—N1—O1119.9 (2)
H5A—C5—H5B107.8C3—N2—C1106.4 (2)
C7—C6—N4106.1 (2)C3—N2—Cd1130.36 (19)
C7—C6—H6126.9C1—N2—Cd1123.02 (17)
N4—C6—H6126.9C3—N3—C2107.5 (2)
C6—C7—N5110.0 (3)C3—N3—C5127.0 (2)
C6—C7—H7125.0C2—N3—C5125.3 (2)
N5—C7—H7125.0C8—N4—C6107.7 (2)
N5—C8—N4110.1 (2)C8—N4—C5127.6 (2)
N5—C8—C9125.5 (2)C6—N4—C5124.6 (2)
N4—C8—C9124.5 (2)C8—N5—C7106.1 (2)
C8—C9—H9A109.5C8—N5—Cd1iv126.22 (18)
C8—C9—H9B109.5C7—N5—Cd1iv125.61 (18)
H9A—C9—H9B109.5N1—O1—Cd1121.74 (17)
C8—C9—H9C109.5
Symmetry codes: (i) x+1, y, z+2; (ii) x, y1, z+1; (iii) x+1, y+1, z+1; (iv) x, y+1, z1.

Experimental details

Crystal data
Chemical formula[Cd(C9H12N4)2(NO3)2]
Mr588.87
Crystal system, space groupTriclinic, P1
Temperature (K)298
a, b, c (Å)7.9252 (9), 9.2783 (10), 9.4118 (10)
α, β, γ (°)62.192 (2), 73.725 (2), 69.787 (2)
V3)568.51 (11)
Z1
Radiation typeMo Kα
µ (mm1)1.02
Crystal size (mm)0.32 × 0.26 × 0.24
Data collection
DiffractometerBruker SMART APEX CCD area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 1996)
Tmin, Tmax0.74, 0.78
No. of measured, independent and
observed [I > 2σ(I)] reflections
5982, 2229, 2168
Rint0.060
(sin θ/λ)max1)0.617
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.031, 0.068, 1.07
No. of reflections2229
No. of parameters162
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.77, 0.44

Computer programs: SMART (Bruker, 2001), SAINT-Plus (Bruker, 2001), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXTL (Bruker, 2001).

Selected geometric parameters (Å, º) top
Cd1—N22.338 (2)Cd1—O12.404 (2)
Cd1—N5i2.383 (2)
N2ii—Cd1—N5i85.17 (8)N2—Cd1—O195.91 (7)
N2—Cd1—N5i94.83 (8)N5i—Cd1—O198.57 (7)
N2ii—Cd1—O184.09 (7)N5iii—Cd1—O181.43 (7)
Symmetry codes: (i) x, y1, z+1; (ii) x+1, y, z+2; (iii) x+1, y+1, z+1.
 

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