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The title compound, [CdCl
2(C
6H
7N
3O)
2], was obtained unintentionally as a product of an attempted reaction of CdCl
2·2.5H
2O and picolinic acid hydrazide, in order to obtain a cadmium(II) complex analogous to a 15-metallacrown-5 complex of the formula [
MCu
5L5]
Xn, with
M = a central metal ion,
L = picolinic acid hydrazide and
X = Cl
−, but with cadmium the only metal present. The coordination geometry around the Cd
II atom can be considered as distorted octahedral, with two bidentate picolinic acid hydrazide ligands, each coordinating through their carbonyl O atom and amino N atom, and two chloride anions. In the crystal structure, intermolecular N—H
Cl and N—H
N hydrogen bonds link the molecules into a two-dimensional network parallel to the (100) plane. The pyridine rings of adjacent networks are involved in π–π stacking interactions, the minimum distance between the ring centroids being 3.693 (2) Å.
Supporting information
CCDC reference: 672771
Key indicators
- Single-crystal X-ray study
- T = 293 K
- Mean (C-C) = 0.004 Å
- R factor = 0.027
- wR factor = 0.067
- Data-to-parameter ratio = 13.3
checkCIF/PLATON results
No syntax errors found
Alert level C
PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low ....... 0.98
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
0 ALERT level A = In general: serious problem
0 ALERT level B = Potentially serious problem
1 ALERT level C = Check and explain
2 ALERT level G = General alerts; check
2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
0 ALERT type 2 Indicator that the structure model may be wrong or deficient
1 ALERT type 3 Indicator that the structure quality may be low
0 ALERT type 4 Improvement, methodology, query or suggestion
0 ALERT type 5 Informative message, check
The ligand picolinic acid hydrazide was prepared as described previously
(Klingele & Brooker, 2004), by refluxing the respective picolinic acid
ethylester for 4 h with a slight excess of hydrazine monohydrate. The product
was recrystallized from ethanol. The cadmium complex was synthesized by adding
a solution of CdCl2·2.5H2O (0.229 g, 1 mmol) in methanol (20 ml) to a
stirred solution of picolinic acid hydrazide (0.274 g, 2 mmol) in methanol (20 ml). The mixture was stirred for 1 h at room temperature. Colourless crystals
were obatined after leaving the solution to evaporate for 3 d. The crystals
were collected by filtration, washed with cold methanol and dried in a
desiccator.
All H atoms were initially located in a difference Fourier map and later placed
in idealized positions and constrained to ride on their parent atoms, with
C—H = 0.93 Å, N—H = 0.86 or 0.90 Å and Uiso(H) = 1.2eq(C).
Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); data reduction: SAINT (Bruker, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: PLATON (Spek, 2003).
Dichloridobis(picolinohydrazide)cadmium(II)
top
Crystal data top
[CdCl2(C6H7N3O)2] | F(000) = 904 |
Mr = 457.60 | Dx = 1.872 Mg m−3 |
Monoclinic, C2/c | Cu Kα radiation, λ = 1.54178 Å |
Hall symbol: -C 2yc | Cell parameters from 2348 reflections |
a = 16.9951 (7) Å | θ = 5.3–71.6° |
b = 6.7365 (2) Å | µ = 13.97 mm−1 |
c = 14.3313 (6) Å | T = 293 K |
β = 98.221 (3)° | Rod, colourless |
V = 1623.89 (11) Å3 | 0.30 × 0.15 × 0.10 mm |
Z = 4 | |
Data collection top
Bruker SMART 6000 diffractometer | 1395 independent reflections |
Radiation source: fine-focus sealed tube | 1349 reflections with I > 2σ(I) |
Crossed Göbel mirrors monochromator | Rint = 0.036 |
ω and ϕ scans | θmax = 66.6°, θmin = 5.3° |
Absorption correction: multi-scan (SADABS; Bruker, 1997) | h = −20→17 |
Tmin = 0.116, Tmax = 0.247 | k = −8→7 |
5326 measured reflections | l = −16→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)] = 0.027 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.067 | H-atom parameters constrained |
S = 1.11 | w = 1/[σ2(Fo2) + (0.0362P)2 + 1.6198P] where P = (Fo2 + 2Fc2)/3 |
1395 reflections | (Δ/σ)max = 0.001 |
105 parameters | Δρmax = 0.52 e Å−3 |
0 restraints | Δρmin = −0.90 e Å−3 |
Crystal data top
[CdCl2(C6H7N3O)2] | V = 1623.89 (11) Å3 |
Mr = 457.60 | Z = 4 |
Monoclinic, C2/c | Cu Kα radiation |
a = 16.9951 (7) Å | µ = 13.97 mm−1 |
b = 6.7365 (2) Å | T = 293 K |
c = 14.3313 (6) Å | 0.30 × 0.15 × 0.10 mm |
β = 98.221 (3)° | |
Data collection top
Bruker SMART 6000 diffractometer | 1395 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 1997) | 1349 reflections with I > 2σ(I) |
Tmin = 0.116, Tmax = 0.247 | Rint = 0.036 |
5326 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.027 | 0 restraints |
wR(F2) = 0.067 | H-atom parameters constrained |
S = 1.11 | Δρmax = 0.52 e Å−3 |
1395 reflections | Δρmin = −0.90 e Å−3 |
105 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 | x | y | z | Uiso*/Ueq | |
C1 | 0.18958 (16) | −0.0129 (4) | 0.4884 (2) | 0.0251 (6) | |
C2 | 0.26626 (17) | 0.0003 (4) | 0.4662 (2) | 0.0285 (6) | |
H2 | 0.2758 | −0.0039 | 0.4039 | 0.034* | |
C3 | 0.32779 (17) | 0.0197 (4) | 0.5395 (2) | 0.0325 (7) | |
H3 | 0.3799 | 0.0312 | 0.5272 | 0.039* | |
C4 | 0.31165 (19) | 0.0218 (5) | 0.6308 (3) | 0.0375 (7) | |
H4 | 0.3525 | 0.0319 | 0.6812 | 0.045* | |
C5 | 0.2330 (2) | 0.0087 (5) | 0.6461 (2) | 0.0392 (8) | |
H5 | 0.2222 | 0.0111 | 0.7079 | 0.047* | |
C6 | 0.12048 (16) | −0.0340 (4) | 0.4117 (2) | 0.0227 (5) | |
N1 | 0.17201 (15) | −0.0072 (4) | 0.57595 (18) | 0.0313 (6) | |
N2 | 0.05532 (15) | −0.1154 (3) | 0.43715 (19) | 0.0253 (5) | |
H2A | 0.0547 | −0.1535 | 0.4943 | 0.030* | |
N3 | −0.01277 (14) | −0.1381 (3) | 0.36872 (18) | 0.0239 (5) | |
H3A | −0.0574 | −0.1181 | 0.3945 | 0.029* | |
H3B | −0.0144 | −0.2608 | 0.3436 | 0.029* | |
O1 | 0.12502 (12) | 0.0236 (3) | 0.33022 (15) | 0.0307 (5) | |
Cl1 | 0.03593 (5) | 0.36372 (10) | 0.13274 (6) | 0.03299 (19) | |
Cd1 | 0.0000 | 0.10888 (4) | 0.2500 | 0.02458 (13) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
C1 | 0.0255 (15) | 0.0245 (13) | 0.0247 (16) | 0.0018 (10) | 0.0019 (11) | 0.0020 (10) |
C2 | 0.0266 (15) | 0.0279 (13) | 0.0309 (17) | 0.0035 (10) | 0.0040 (12) | 0.0014 (11) |
C3 | 0.0203 (14) | 0.0309 (15) | 0.045 (2) | 0.0009 (11) | 0.0011 (12) | 0.0001 (13) |
C4 | 0.0320 (17) | 0.0385 (17) | 0.038 (2) | −0.0031 (13) | −0.0099 (13) | 0.0008 (13) |
C5 | 0.0374 (18) | 0.053 (2) | 0.0251 (19) | −0.0067 (14) | −0.0012 (13) | 0.0007 (14) |
C6 | 0.0240 (13) | 0.0237 (13) | 0.0202 (15) | 0.0035 (10) | 0.0029 (10) | 0.0017 (10) |
N1 | 0.0280 (13) | 0.0412 (14) | 0.0237 (15) | −0.0035 (10) | 0.0006 (10) | 0.0008 (10) |
N2 | 0.0239 (12) | 0.0305 (13) | 0.0207 (15) | −0.0016 (8) | 0.0006 (10) | 0.0032 (8) |
N3 | 0.0220 (12) | 0.0272 (11) | 0.0216 (14) | −0.0028 (9) | 0.0002 (9) | −0.0009 (9) |
O1 | 0.0239 (10) | 0.0433 (12) | 0.0245 (12) | −0.0003 (8) | 0.0018 (8) | 0.0058 (9) |
Cl1 | 0.0444 (4) | 0.0284 (3) | 0.0278 (5) | 0.0019 (3) | 0.0107 (3) | 0.0038 (3) |
Cd1 | 0.02608 (18) | 0.02668 (18) | 0.0197 (2) | 0.000 | −0.00130 (11) | 0.000 |
Geometric parameters (Å, º) top
C1—N1 | 1.331 (4) | C6—N2 | 1.332 (4) |
C1—C2 | 1.388 (4) | N2—N3 | 1.414 (3) |
C1—C6 | 1.497 (4) | N2—H2A | 0.86 |
C2—C3 | 1.378 (4) | N3—Cd1 | 2.412 (2) |
C2—H2 | 0.93 | N3—H3A | 0.90 |
C3—C4 | 1.375 (5) | N3—H3B | 0.90 |
C3—H3 | 0.93 | O1—Cd1 | 2.338 (2) |
C4—C5 | 1.387 (5) | Cl1—Cd1 | 2.5372 (7) |
C4—H4 | 0.93 | Cd1—O1i | 2.338 (2) |
C5—N1 | 1.342 (4) | Cd1—N3i | 2.412 (2) |
C5—H5 | 0.93 | Cd1—Cl1i | 2.5371 (7) |
C6—O1 | 1.243 (4) | | |
| | | |
N1—C1—C2 | 124.0 (3) | N2—N3—Cd1 | 105.50 (15) |
N1—C1—C6 | 115.9 (2) | N2—N3—H3A | 110.6 |
C2—C1—C6 | 120.1 (3) | Cd1—N3—H3A | 110.6 |
C3—C2—C1 | 117.8 (3) | N2—N3—H3B | 110.6 |
C3—C2—H2 | 121.1 | Cd1—N3—H3B | 110.6 |
C1—C2—H2 | 121.1 | H3A—N3—H3B | 108.8 |
C4—C3—C2 | 119.6 (3) | C6—O1—Cd1 | 111.37 (17) |
C4—C3—H3 | 120.2 | O1—Cd1—O1i | 151.56 (11) |
C2—C3—H3 | 120.2 | O1—Cd1—N3 | 69.56 (8) |
C3—C4—C5 | 118.5 (3) | O1i—Cd1—N3 | 90.59 (8) |
C3—C4—H4 | 120.7 | O1—Cd1—N3i | 90.59 (8) |
C5—C4—H4 | 120.7 | O1i—Cd1—N3i | 69.56 (8) |
N1—C5—C4 | 123.0 (3) | N3—Cd1—N3i | 92.74 (12) |
N1—C5—H5 | 118.5 | O1—Cd1—Cl1i | 97.38 (6) |
C4—C5—H5 | 118.5 | O1i—Cd1—Cl1i | 101.77 (5) |
O1—C6—N2 | 123.4 (3) | N3—Cd1—Cl1i | 86.86 (6) |
O1—C6—C1 | 120.9 (2) | N3i—Cd1—Cl1i | 171.32 (6) |
N2—C6—C1 | 115.7 (2) | O1—Cd1—Cl1 | 101.77 (5) |
C1—N1—C5 | 117.1 (3) | O1i—Cd1—Cl1 | 97.38 (6) |
C6—N2—N3 | 119.0 (2) | N3—Cd1—Cl1 | 171.32 (6) |
C6—N2—H2A | 120.5 | N3i—Cd1—Cl1 | 86.86 (6) |
N3—N2—H2A | 120.5 | Cl1i—Cd1—Cl1 | 94.84 (3) |
| | | |
N1—C1—C2—C3 | 0.3 (4) | C1—C6—N2—N3 | 179.3 (2) |
C6—C1—C2—C3 | 179.9 (3) | C6—N2—N3—Cd1 | −24.3 (3) |
C1—C2—C3—C4 | 1.1 (4) | N2—C6—O1—Cd1 | 26.2 (3) |
C2—C3—C4—C5 | −1.4 (5) | C1—C6—O1—Cd1 | −153.2 (2) |
C3—C4—C5—N1 | 0.4 (5) | C6—O1—Cd1—O1i | −75.72 (18) |
N1—C1—C6—O1 | 155.8 (3) | C6—O1—Cd1—N3 | −27.42 (18) |
C2—C1—C6—O1 | −23.9 (4) | C6—O1—Cd1—N3i | −120.12 (19) |
N1—C1—C6—N2 | −23.6 (4) | C6—O1—Cd1—Cl1i | 56.43 (19) |
C2—C1—C6—N2 | 156.7 (3) | C6—O1—Cd1—Cl1 | 152.96 (18) |
C2—C1—N1—C5 | −1.2 (4) | N2—N3—Cd1—O1 | 25.21 (15) |
C6—C1—N1—C5 | 179.1 (3) | N2—N3—Cd1—O1i | −175.62 (16) |
C4—C5—N1—C1 | 0.9 (5) | N2—N3—Cd1—N3i | 114.82 (18) |
O1—C6—N2—N3 | −0.1 (4) | N2—N3—Cd1—Cl1i | −73.86 (16) |
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—H2A···Cl1ii | 0.86 | 2.49 | 3.321 (3) | 161 |
N3—H3A···N1iii | 0.90 | 2.22 | 3.086 (4) | 162 |
N3—H3B···Cl1iv | 0.90 | 2.59 | 3.379 (2) | 147 |
Symmetry codes: (ii) x, −y, z+1/2; (iii) −x, −y, −z+1; (iv) −x, y−1, −z+1/2. |
Experimental details
Crystal data |
Chemical formula | [CdCl2(C6H7N3O)2] |
Mr | 457.60 |
Crystal system, space group | Monoclinic, C2/c |
Temperature (K) | 293 |
a, b, c (Å) | 16.9951 (7), 6.7365 (2), 14.3313 (6) |
β (°) | 98.221 (3) |
V (Å3) | 1623.89 (11) |
Z | 4 |
Radiation type | Cu Kα |
µ (mm−1) | 13.97 |
Crystal size (mm) | 0.30 × 0.15 × 0.10 |
|
Data collection |
Diffractometer | Bruker SMART 6000 diffractometer |
Absorption correction | Multi-scan (SADABS; Bruker, 1997) |
Tmin, Tmax | 0.116, 0.247 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 5326, 1395, 1349 |
Rint | 0.036 |
(sin θ/λ)max (Å−1) | 0.595 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.027, 0.067, 1.11 |
No. of reflections | 1395 |
No. of parameters | 105 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.52, −0.90 |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N2—H2A···Cl1i | 0.86 | 2.49 | 3.321 (3) | 161 |
N3—H3A···N1ii | 0.90 | 2.22 | 3.086 (4) | 162 |
N3—H3B···Cl1iii | 0.90 | 2.59 | 3.379 (2) | 147 |
Symmetry codes: (i) x, −y, z+1/2; (ii) −x, −y, −z+1; (iii) −x, y−1, −z+1/2. |
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Metallocrowns are cyclic polynuclear complexes, which are the inorganic analogues of crown ethers, both in structure and function (Bodwin et al., 2001). In contrast to the numerous 12-metallacrown-4 structures reported, there are only a few examples of ligands capable of forming planar rings of the 15-metallacrown-5 structure type. Especially α-amino- and picolinehydroxamic acids have been used as precursor ligands in the synthesis of these complexes (Seda et al., 2007; Parac-Vogt et al., 2006; Stemmler, Kampf et al., 1996; Stemmler, Barwinski et al., 1996).
The title compound was obtained unintentionally as a product of an attempted reaction of CdCl2·2.5H2O and picolinic acid hydrazide, in order to obtain a cadmium(II)-complex analogous to a 15-metallacrown-5, but with cadmium the only metal present. Here, picolinic acid hydrazide was used instead of various α-amino-, mandelo-, or picolinehydroxamic acids as a precursor ligand (Seda et al., 2007; Parac-Vogt et al., 2006; Stemmler, Kampf et al., 1996; Stemmler, Barwinski et al., 1996)
The asymmetric unit of the title compound consists of one-half molecule of the complex, with the CdII ion lying on a twofold rotation axis. The coordination geometry around the CdII ion can be considered as a slightly distorted octahedron, with two bidentate picolinic acid hydrazide ligands and two chloride anions (Fig. 1).
As observed in the structure of picolinic acid hydrazide (Zareef et al., 2006), the aromatic C—C bond lengths within the phenyl ring vary between 1.375 (5) Å and 1.388 (5) Å. Additionaly, an opening of the angles N1—C1—C2 (124.0 (3)°) and N1—C5—C4 (123.0 (3)°) is observed, due to the presence of the nitrogen atom, N1 (Zareef et al., 2006). As a consequence, a decrease of the ring angles C1—C2—C3 (117.8 (3)°), C2—C3—C4 (119.6 (3)°), C3—C4—C5 (118.5 (3)°) and C1—N1—C5 (117.1 (3)°) is noticed. The pyridine ring is twisted away with respect to the rest of the picolinic acid hydrazide molecule; the dihedral angle between the N1/C1—C5 and C1/C6/O1/N2/N3 is 23.3 (1)°.
In the crystal structure, intermolecular N—H···Cl and N—H···N hydrogen bonds link the molecules in to a two-dimensional network parallel to the (1 0 0) plane (Fig. 2). In addition, π-π stacking interactions are observed between the pyridine rings of the adjacent networks, with the distance between the ring centroids being 3.815 (2) or 3.693 (2) Å.
The reported structure is homologous to the structure of dichloro-bis(picolinic acid hydrazide)-mangenese (Tsintsadze et al., 1979) (reference code PHYZMN, CSD (Version 5.28) (Allen, 2002)).