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The hydro­thermal reaction of cadmium(II) nitrate with 5-amino-2,4,6-triiodo­isophthalic acid and pyridine in DMF solution leads to the formation of the title compound, [Cd(C8H2I3NO4)(C5H5N)2]n. The structure contains a four-coordinate Cd2+ ion in a distorted tetra­hedral geometry, which lies on a crystallographic twofold rotation axis. The Cd2+ ion is bonded to two N atoms from two pyridine ligands and two carboxyl­ate O atoms from two 5-amino-2,4,6-triiodo­isophthalate anions. The Cd—O distances are 2.429 (5) and 2.305 (5) Å and the Cd—N distance is 2.236 (8) Å. The two carboxyl­ate groups of individual 5-amino-2,4,6-triiodo­isophthalate anions act as a bridge to the Cd2+ atoms. leading to a chain structure along the c axis.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536810039498/si2296sup1.cif
Contains datablocks I, New_Global_Publ_Block

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536810039498/si2296Isup2.hkl
Contains datablock I

CCDC reference: 799426

Key indicators

  • Single-crystal X-ray study
  • T = 293 K
  • Mean [sigma](C-C) = 0.014 Å
  • R factor = 0.038
  • wR factor = 0.089
  • Data-to-parameter ratio = 20.3

checkCIF/PLATON results

No syntax errors found



Alert level C PLAT220_ALERT_2_C Large Non-Solvent C Ueq(max)/Ueq(min) ... 3.44 Ratio PLAT242_ALERT_2_C Check Low Ueq as Compared to Neighbors for N2 PLAT342_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang .. 14 PLAT234_ALERT_4_C Large Hirshfeld Difference C9 -- C10 .. 0.17 Ang. PLAT912_ALERT_4_C Missing # of FCF Reflections Above STh/L= 0.600 2
Alert level G REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is correct. If it is not, please give the correct count in the _publ_section_exptl_refinement section of the submitted CIF. From the CIF: _diffrn_reflns_theta_max 28.16 From the CIF: _reflns_number_total 2714 Count of symmetry unique reflns 1618 Completeness (_total/calc) 167.74% TEST3: Check Friedels for noncentro structure Estimate of Friedel pairs measured 1096 Fraction of Friedel pairs measured 0.677 Are heavy atom types Z>Si present yes PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints ....... 60 PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature 293 K PLAT200_ALERT_1_G Check the Reported _diffrn_ambient_temperature 293 K PLAT764_ALERT_4_G Overcomplete CIF Bond List Detected (Rep/Expd) . 1.18 Ratio
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 5 ALERT level C = Check and explain 5 ALERT level G = General alerts; check 2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 2 ALERT type 2 Indicator that the structure model may be wrong or deficient 2 ALERT type 3 Indicator that the structure quality may be low 4 ALERT type 4 Improvement, methodology, query or suggestion 0 ALERT type 5 Informative message, check

Comment top

5-Amino-2,4,6-triiodoisophthalic acid (ATIA), is the precursor and core structure of triiodinated contrast media used in radiology (Estep et al., 2000). The crystal structure of this compound was reported recently (Beck et al., 2008), however, there are very few studies that have been reported on the structural characterization of its metal complexes (Dai et al., 2008; Zhang et al., 2008). Here we report the synthesis and crystal structure of the title complex catena-[bis(pyridine)-µ-5-amino-2,4,6-triiodoisophthalic acid-O,O-cadmium(II)].

In the title complex the central cadmium ion is coordinated by two nitrogen atoms from two pyridine ligands and two oxygen atoms from different ATIA ligands in a tetrahedral geometry. The bond lengths are 2.236 (8)Å for Cd1—N2; 2.305 (5) Å for Cd1—O2 and 2.429 (5) Å for Cd1—O1. Both carboxylate groups of ATIA ligand are deprotonated during the reaction, and the whole ligand acts as a bridging linker to connect two cadmium ions. Thus, the [Cd(pyr)2] units are infinitely connected by ATIA ligands along the c axis to give rise to a one-dimensional chain structure.

Related literature top

For the isotypic Hg complex, see: Zhang et al. (2008). For the structure of 5-amino-2,4,6-triiodoisophthalic acid monohydrate, see: Beck & Sheldrick (2008). For the structures of related metal complexes, see Dai et al. (2008).For the use of triiodinated aromatic compounds in radiology, see: Estep et al. (2000).

Experimental top

5-amino-2,4,6-triiodoisophthalic acid (0.5 mmol) was dissolved in 10 ml DMA, in which Cd(NO3)2(0.5 mmol) and 20 µl pyridine were added in. The mixture was sealed in a Pyrex tube and heated at 358 K for 3 d. After cooling to room temperature, light yellow block crystals were obtained.

Refinement top

All H atoms were positioned geometrically and constrained as riding atoms, with C—H distance of 0.93 Å and Uiso(H) set to 1.2 Ueq(C) of the parent atom.

Structure description top

5-Amino-2,4,6-triiodoisophthalic acid (ATIA), is the precursor and core structure of triiodinated contrast media used in radiology (Estep et al., 2000). The crystal structure of this compound was reported recently (Beck et al., 2008), however, there are very few studies that have been reported on the structural characterization of its metal complexes (Dai et al., 2008; Zhang et al., 2008). Here we report the synthesis and crystal structure of the title complex catena-[bis(pyridine)-µ-5-amino-2,4,6-triiodoisophthalic acid-O,O-cadmium(II)].

In the title complex the central cadmium ion is coordinated by two nitrogen atoms from two pyridine ligands and two oxygen atoms from different ATIA ligands in a tetrahedral geometry. The bond lengths are 2.236 (8)Å for Cd1—N2; 2.305 (5) Å for Cd1—O2 and 2.429 (5) Å for Cd1—O1. Both carboxylate groups of ATIA ligand are deprotonated during the reaction, and the whole ligand acts as a bridging linker to connect two cadmium ions. Thus, the [Cd(pyr)2] units are infinitely connected by ATIA ligands along the c axis to give rise to a one-dimensional chain structure.

For the isotypic Hg complex, see: Zhang et al. (2008). For the structure of 5-amino-2,4,6-triiodoisophthalic acid monohydrate, see: Beck & Sheldrick (2008). For the structures of related metal complexes, see Dai et al. (2008).For the use of triiodinated aromatic compounds in radiology, see: Estep et al. (2000).

Computing details top

Data collection: SMART (Bruker, 2003); cell refinement: SAINT (Bruker, 2003); data reduction: SAINT (Bruker, 2003); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XP in SHELXTL (Sheldrick, 2008) and DIAMOND (Brandenburg, 2000); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. ORTEP plot of the title complex with atom numbering scheme. Thermal ellipsoids are drawn at 40% probability level.
[Figure 2] Fig. 2. A section of the infinite [Cd(ATIA)(pyr)2]n chain along the c axis.
catena-Poly[[dipyridinecadmium(II)]-µ-5-amino-2,4,6- triiodoisophthalato] top
Crystal data top
[Cd(C8H2I3NO4)(C5H5N)2]Dx = 2.482 Mg m3
Mr = 827.41Mo Kα radiation, λ = 0.71073 Å
Tetragonal, P41212Cell parameters from 1949 reflections
Hall symbol: P 4abw 2nwθ = 2.2–28.2°
a = 11.824 (3) ŵ = 5.20 mm1
c = 15.841 (9) ÅT = 293 K
V = 2214.7 (15) Å3Block, light yellow
Z = 40.25 × 0.25 × 0.20 mm
F(000) = 1520
Data collection top
Bruker SMART CCD
diffractometer
2714 independent reflections
Radiation source: fine-focus sealed tube1949 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.054
Detector resolution: none pixels mm-1θmax = 28.2°, θmin = 2.2°
phi and ω scansh = 1515
Absorption correction: multi-scan
(SADABS; Bruker 2003)
k = 1415
Tmin = 0.357, Tmax = 0.423l = 1721
14248 measured reflections
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.038H-atom parameters constrained
wR(F2) = 0.089 w = 1/[σ2(Fo2) + (0.0338P)2 + 2.974P]
where P = (Fo2 + 2Fc2)/3
S = 1.02(Δ/σ)max < 0.001
2714 reflectionsΔρmax = 0.60 e Å3
134 parametersΔρmin = 0.87 e Å3
60 restraintsAbsolute structure: Flack (1983), 1096 Friedel pairs
Primary atom site location: structure-invariant direct methodsAbsolute structure parameter: 0.04 (6)
Crystal data top
[Cd(C8H2I3NO4)(C5H5N)2]Z = 4
Mr = 827.41Mo Kα radiation
Tetragonal, P41212µ = 5.20 mm1
a = 11.824 (3) ÅT = 293 K
c = 15.841 (9) Å0.25 × 0.25 × 0.20 mm
V = 2214.7 (15) Å3
Data collection top
Bruker SMART CCD
diffractometer
2714 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker 2003)
1949 reflections with I > 2σ(I)
Tmin = 0.357, Tmax = 0.423Rint = 0.054
14248 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.038H-atom parameters constrained
wR(F2) = 0.089Δρmax = 0.60 e Å3
S = 1.02Δρmin = 0.87 e Å3
2714 reflectionsAbsolute structure: Flack (1983), 1096 Friedel pairs
134 parametersAbsolute structure parameter: 0.04 (6)
60 restraints
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*/UeqOcc. (<1)
Cd10.62771 (5)0.37229 (5)0.25000.0572 (2)
I10.51631 (4)0.51631 (4)0.00000.0630 (2)
I20.28105 (5)0.12921 (6)0.17206 (4)0.0802 (2)
N10.1416 (5)0.1416 (5)0.00000.064 (2)
H1A0.13570.09610.04210.077*0.50
H1B0.09610.13570.04210.077*0.50
N20.6179 (7)0.2214 (7)0.3348 (5)0.0771 (19)
O10.5507 (5)0.2646 (5)0.1328 (3)0.0668 (15)
O20.6079 (5)0.5525 (4)0.3035 (3)0.0684 (16)
C10.2221 (6)0.2221 (6)0.00000.051 (2)
C20.2982 (6)0.2357 (6)0.0666 (4)0.0462 (16)
C30.3809 (6)0.3171 (6)0.0673 (4)0.0479 (17)
C40.3908 (5)0.3908 (5)0.00000.043 (2)
C50.4652 (7)0.3247 (7)0.1375 (5)0.0540 (19)
C60.5209 (10)0.1691 (10)0.3519 (9)0.113 (3)
H60.45600.19460.32480.135*
C70.5108 (12)0.0835 (12)0.4049 (10)0.134 (4)
H70.44190.04640.41140.161*
C80.6063 (12)0.0494 (13)0.4514 (11)0.147 (4)
H80.60260.00390.49440.177*
C90.7027 (12)0.0999 (13)0.4288 (10)0.143 (4)
H90.77010.07450.45230.172*
C100.7060 (10)0.1827 (10)0.3754 (8)0.113 (4)
H100.77550.21690.36540.135*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cd10.0617 (3)0.0617 (3)0.0482 (4)0.0120 (4)0.0049 (3)0.0049 (3)
I10.0559 (3)0.0559 (3)0.0773 (5)0.0148 (3)0.0062 (3)0.0062 (3)
I20.0755 (4)0.0957 (5)0.0695 (3)0.0276 (4)0.0027 (3)0.0291 (3)
N10.060 (4)0.060 (4)0.071 (5)0.027 (5)0.007 (4)0.007 (4)
N20.075 (5)0.073 (5)0.083 (5)0.004 (4)0.013 (4)0.005 (4)
O10.054 (3)0.091 (4)0.056 (3)0.008 (3)0.006 (3)0.012 (3)
O20.091 (4)0.056 (3)0.058 (3)0.003 (3)0.026 (3)0.005 (2)
C10.047 (3)0.047 (3)0.058 (5)0.009 (5)0.003 (4)0.003 (4)
C20.041 (4)0.050 (4)0.048 (4)0.001 (3)0.005 (3)0.001 (3)
C30.040 (4)0.052 (4)0.052 (4)0.006 (3)0.009 (3)0.005 (3)
C40.036 (3)0.036 (3)0.058 (5)0.000 (4)0.013 (3)0.013 (3)
C50.048 (5)0.061 (5)0.053 (4)0.011 (4)0.006 (4)0.003 (4)
C60.077 (6)0.105 (7)0.156 (9)0.028 (6)0.026 (6)0.040 (6)
C70.102 (7)0.127 (8)0.173 (9)0.027 (7)0.027 (7)0.054 (7)
C80.105 (8)0.142 (8)0.196 (9)0.010 (7)0.031 (8)0.062 (8)
C90.108 (8)0.129 (8)0.192 (9)0.026 (7)0.043 (8)0.046 (8)
C100.075 (6)0.102 (7)0.161 (9)0.008 (6)0.038 (6)0.048 (6)
Geometric parameters (Å, º) top
Cd1—N22.236 (8)C1—C21.395 (9)
Cd1—N2i2.236 (8)C1—C2ii1.395 (9)
Cd1—O2i2.305 (5)C2—C31.373 (9)
Cd1—O22.305 (5)C3—C41.382 (8)
Cd1—O1i2.429 (5)C3—C51.495 (11)
Cd1—O12.429 (5)C4—C3ii1.382 (8)
Cd1—C5i2.681 (8)C5—O2i1.246 (9)
Cd1—C52.681 (8)C6—C71.321 (16)
I1—C42.098 (8)C6—H60.9300
I2—C22.102 (7)C7—C81.407 (17)
N1—C11.346 (12)C7—H70.9300
N1—H1A0.8600C8—C91.336 (17)
N1—H1B0.8600C8—H80.9300
N2—C101.307 (12)C9—C101.293 (16)
N2—C61.331 (13)C9—H90.9300
O1—C51.239 (10)C10—H100.9300
O2—C5i1.246 (9)
N2—Cd1—N2i116.3 (4)C5i—O2—Cd193.2 (5)
N2—Cd1—O2i104.7 (3)N1—C1—C2122.5 (4)
N2i—Cd1—O2i120.8 (2)N1—C1—C2ii122.5 (4)
N2—Cd1—O2120.8 (2)C2—C1—C2ii115.0 (9)
N2i—Cd1—O2104.7 (3)C3—C2—C1123.1 (7)
O2i—Cd1—O287.0 (3)C3—C2—I2118.8 (5)
N2—Cd1—O1i82.4 (2)C1—C2—I2118.0 (5)
N2i—Cd1—O1i91.2 (2)C2—C3—C4119.8 (7)
O2i—Cd1—O1i136.7 (2)C2—C3—C5121.6 (7)
O2—Cd1—O1i54.96 (18)C4—C3—C5118.6 (6)
N2—Cd1—O191.2 (2)C3ii—C4—C3119.2 (8)
N2i—Cd1—O182.4 (2)C3ii—C4—I1120.4 (4)
O2i—Cd1—O154.96 (18)C3—C4—I1120.4 (4)
O2—Cd1—O1136.7 (2)O1—C5—O2i123.3 (7)
O1i—Cd1—O1167.9 (3)O1—C5—C3117.7 (7)
N2—Cd1—C5i100.6 (3)O2i—C5—C3119.0 (7)
N2i—Cd1—C5i101.2 (3)O1—C5—Cd164.8 (4)
O2i—Cd1—C5i111.4 (2)O2i—C5—Cd159.1 (4)
O2—Cd1—C5i27.7 (2)C3—C5—Cd1169.9 (5)
O1i—Cd1—C5i27.5 (2)C7—C6—N2124.3 (13)
O1—Cd1—C5i164.3 (3)C7—C6—H6117.8
N2—Cd1—C5101.2 (3)N2—C6—H6117.8
N2i—Cd1—C5100.6 (3)C6—C7—C8118.7 (14)
O2i—Cd1—C527.7 (2)C6—C7—H7120.7
O2—Cd1—C5111.4 (2)C8—C7—H7120.7
O1i—Cd1—C5164.3 (3)C9—C8—C7114.6 (15)
O1—Cd1—C527.5 (2)C9—C8—H8122.7
C5i—Cd1—C5138.0 (4)C7—C8—H8122.7
C1—N1—H1A120.0C10—C9—C8122.6 (15)
C1—N1—H1B120.0C10—C9—H9118.7
H1A—N1—H1B120.0C8—C9—H9118.7
C10—N2—C6115.1 (9)C9—C10—N2124.2 (12)
C10—N2—Cd1122.3 (7)C9—C10—H10117.9
C6—N2—Cd1122.5 (7)N2—C10—H10117.9
C5—O1—Cd187.7 (5)
Symmetry codes: (i) y+1, x+1, z+1/2; (ii) y, x, z.

Experimental details

Crystal data
Chemical formula[Cd(C8H2I3NO4)(C5H5N)2]
Mr827.41
Crystal system, space groupTetragonal, P41212
Temperature (K)293
a, c (Å)11.824 (3), 15.841 (9)
V3)2214.7 (15)
Z4
Radiation typeMo Kα
µ (mm1)5.20
Crystal size (mm)0.25 × 0.25 × 0.20
Data collection
DiffractometerBruker SMART CCD
Absorption correctionMulti-scan
(SADABS; Bruker 2003)
Tmin, Tmax0.357, 0.423
No. of measured, independent and
observed [I > 2σ(I)] reflections
14248, 2714, 1949
Rint0.054
(sin θ/λ)max1)0.664
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.038, 0.089, 1.02
No. of reflections2714
No. of parameters134
No. of restraints60
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.60, 0.87
Absolute structureFlack (1983), 1096 Friedel pairs
Absolute structure parameter0.04 (6)

Computer programs: SMART (Bruker, 2003), SAINT (Bruker, 2003), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), XP in SHELXTL (Sheldrick, 2008) and DIAMOND (Brandenburg, 2000), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

 

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