Crystal structure of bis­(acetato-κO)bis­(pyridine-2-carboxamide oxime-κ²N,N′)cadmium ethanol disolvate

In this Cd^II complex incorporating two monodentate acetate groups and two N,N′-chelating pyridine-2-carboxamide oxime ligands, mol­ecules are assembled into chains along the c axis via N—H...O hydrogen bonding. The resulting chains are further assembled by ethanol solvent mol­ecules into a three-dimensional supermolecular structure.

Key indicators

• Single-crystal X-ray study
• T = 294 K
• Mean [sigma](C-C) = 0.009 Å
• R factor = 0.047
• wR factor = 0.125
• Data-to-parameter ratio = 13.9

checkCIF/PLATON results

No syntax errors found



Alert level B
            Crystal system given = monoclinic
PLAT735_ALERT_1_B D-H     Calc     0.85(6), Rep   0.851(10) ......          6 su-Rat
              O4   -H4A     1.555   1.555                    #         37

Alert level C
PLAT242_ALERT_2_C Low       Ueq as Compared to Neighbors for .....         C7 Check
PLAT342_ALERT_3_C Low Bond Precision on  C-C Bonds ...............     0.0086 Ang.
PLAT360_ALERT_2_C Short  C(sp3)-C(sp3) Bond  C9     -   C10    ...       1.41 Ang.
PLAT731_ALERT_1_C Bond    Calc     0.84(4), Rep   0.846(10) ......          4 su-Rat
              O1   -H1      1.555   1.555                    #          7
PLAT731_ALERT_1_C Bond    Calc     0.85(4), Rep   0.851(10) ......          4 su-Rat
              N2   -H2A     1.555   1.555                    #         13
PLAT731_ALERT_1_C Bond    Calc     0.85(4), Rep   0.847(10) ......          4 su-Rat
              N2   -H2B     1.555   1.555                    #         14
PLAT731_ALERT_1_C Bond    Calc     0.85(6), Rep   0.851(10) ......          6 su-Rat
              O4   -H4A     1.555   1.555                    #         30
PLAT735_ALERT_1_C D-H     Calc     0.84(4), Rep   0.846(10) ......          4 su-Rat
              O1   -H1      1.555   1.555                    #         37
PLAT735_ALERT_1_C D-H     Calc     0.85(4), Rep   0.851(10) ......          4 su-Rat
              N2   -H2A     1.555   1.555                    #         37
PLAT735_ALERT_1_C D-H     Calc     0.85(4), Rep   0.847(10) ......          4 su-Rat
              N2   -H2B     1.555   1.555                    #         37
PLAT736_ALERT_1_C H...A   Calc     2.08(7), Rep     2.09(3) ......        2.3 su-Rat
              H4A  -O3      1.555   8.465                    #         37
PLAT910_ALERT_3_C Missing # of FCF Reflections Below Th(Min) .....          5 Report
PLAT934_ALERT_3_C Number of (Iobs-Icalc)/SigmaW > 10 Outliers ....          1 Check

Alert level G
PLAT005_ALERT_5_G No _iucr_refine_instructions_details  in the CIF     Please Do !
PLAT860_ALERT_3_G Number of Least-Squares Restraints .............          4 Note

   0 ALERT level A = Most likely a serious problem - resolve or explain
   1 ALERT level B = A potentially serious problem, consider carefully
  13 ALERT level C = Check. Ensure it is not caused by an omission or oversight
   2 ALERT level G = General information/check it is not something unexpected

   9 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
   4 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion
   1 ALERT type 5 Informative message, check

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S1. Chemical context

The monoanions of simple of 2-pyridyl oximes, (py)C(R)NOH (R = a non-coordinating group, e.g. H, Me, Ph etc.), are remarkable sources of homo- and heterometallic complexes with novel structures and inter­esting physical properties (Miyasaka et al., 2003; Stamatatos et al., 2007). A logical extension of such studies is the investigation of the coordination chemistry of analogous organic molecules in which the non-donor R group is replaced by a donor group (e.g. pyridine, cyano etc.; Alcazar et al., 2013; Escuer et al., 2011). When R is an amino group, the resulting ligand is pyridine-2-amidoxime (systematic name: N-hy­droxy-pyridine-2-carboxamidine), (py)C(NH₂)NOH, which belongs to the class of amidoximes. The presence of the amine functionality is expected to alter the coordination behaviour of this ligand in comparison with that of the (py)C(R)NOH (R = a non-coordinating group) ligands. Characteristics that differentiate the amino group are its coordination capability, potential for deprotonation, different electronic properties and hydrogen-bonding effects. In the present work, we report the first use of (py)C(NH₂)NOH in Cd^II coordination chemistry by describing the synthesis and structure of the mononuclear titlecompound.

S2. Structural commentary

The title complex consists of isolated [Cd(O₂CMe)₂{(py)C(NH₂)NOH}₂] complex molecules and ethanol solvent molecules. It crystallizes in the monoclinic space group C2/c and the central Cd^II atom is located on a twofold axis (Wyckoff site 4e). The Cd^II atom is coordinated by two monodentate MeCO^2- groups and two N,N'-chelating (η²)(py)C(NH₂)NOH ligands (Fig. 1 and Table 1). The (py)C(NH₂)NOH donor atoms are the N atoms of the neutral oxime and the 2-pyridyl groups. The amino N atom of each ligand remains uncoordinated albeit participating in an extensive inter­molecular hydrogen-bonding network. Each of the two coordinating (py)C(NH₂)NOH molecules results in the formation of a five-membered chelate ring including a Cd^II atom, in which the chelate angle N1—Cd1—N1 [86.7 (2)°] is noteably larger than comparable angles found in [Cd(HCO₂)₂(pya)₂] (pya = pyridine-2-aldoxime; Croitor et al., 2013) and Cd—N distances of 2.413 (4) and 2.315 (3) Å.

S3. Supra­molecular features

Table 2 shows the hydrogen-bonding inter­actions. There are two very strong symmetry-related intra­molecular hydrogen bonds between the unbound oxime (–O1—H1) group and uncoordinating acetate atom O3. Uncoordinating amino atom N2 acts as a donor for two hydrogen bonds; in one of these, the acceptor is coordinating atom O2 from the acetate group, which leads to the formation of chains running along the c-axis direction (Fig. 2). These chains are further linked by hydrogen bonds involving the ethanol solvent molecule (O4), acting as a donor for the uncoordinating carboxyl­ate O atom (O3) and as an acceptor for the remaining amino H atom H2B (Table 2 and Fig. 3).

S4. Synthesis and crystallization

A stoichiometric amount in the ratio of 2:1 of (py)C(NH₂)NOH and Cd(OAc)₂·3H₂O were dissolved in 20 ml ethanol and 10 ml DMF, and the solution left to evaporate slowly to afford colourless block-like crystals after three weeks at room temperature.

S5. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 3. H atoms bonded to C atoms were placed in geometrically calculated position and were refined using a riding model, with C—H = 0.93 or 0.96 Å and U_iso(H) = 1.2U_eq(C). The N- and O-bound H atoms were located in a difference map and the coordinates were refined with N—H = 0.86 (1) Å and U_iso(H) = 1.2U_eq(N) or 1.5U_eq(O).

Related literature

For related literature, see: Alcazar et al. (2013); Escuer et al. (2011); Miyasaka et al. (2003); Stamatatos et al. (2007).

Computing details

Data collection: CrysAlis PRO (Agilent, 2011); cell refinement: CrysAlis PRO (Agilent, 2011); data reduction: CrysAlis PRO (Agilent, 2011); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: Olex2 (Dolomanov et al., 2009); software used to prepare material for publication: Olex2 (Dolomanov et al., 2009).

Figures

	Fig. 1. The title compound with displacement ellipsoids are drawn at the 30% probability level. [Symmetry code: (i) -x+1, y, -z+3/2.]
	Fig. 2. The hydrogen-bonded chain along the c axis. Dashed lines represent hydrogen bonds and H atoms bonded to C atoms have been omitted for clarity.
	Fig. 3. The crystal structure projected along the c axis. Dashed lines represent hydrogen bonds and H atoms bonded to C atoms have been omitted for clarity.

Bis(acetato-κO)bis(pyridine-2-carboxamide oxime-κ²N,N')cadmium ethanol disolvate

Crystal data

[Cd(C2H3O2)2(C6H7N3O)2]·2C2H6O	F(000) = 1224
Mr = 596.92	Dx = 1.515 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 15.894 (3) Å	Cell parameters from 1816 reflections
b = 10.9654 (17) Å	θ = 2.9–29.6°
c = 15.0212 (16) Å	µ = 0.89 mm^−1
β = 91.746 (12)°	T = 294 K
V = 2616.7 (7) Å^3	Block, colourless
Z = 4	0.28 × 0.26 × 0.2 mm

Data collection

Agilent Xcalibur, Atlas, Gemini ultra diffractometer	2400 independent reflections
Radiation source: Enhance (Mo) X-ray Source	2017 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.050
Detector resolution: 10.3592 pixels mm^-1	θmax = 25.4°, θmin = 3.5°
ω scans	h = −19→16
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2011)	k = −13→11
Tmin = 0.910, Tmax = 1.000	l = −18→16
5661 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.047	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.125	H atoms treated by a mixture of independent and constrained refinement
S = 1.05	w = 1/[σ^2(Fo^2) + (0.0689P)^2] where P = (Fo^2 + 2Fc^2)/3
2400 reflections	(Δ/σ)max < 0.001
173 parameters	Δρmax = 0.85 e Å^−3
4 restraints	Δρmin = −0.48 e Å^−3

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
Cd1	0.5000	0.55546 (4)	0.7500	0.0336 (2)
O1	0.3289 (2)	0.5799 (3)	0.6185 (2)	0.0456 (9)
H1	0.323 (4)	0.623 (5)	0.664 (2)	0.068*
O2	0.5829 (2)	0.6898 (3)	0.67588 (19)	0.0448 (8)
O3	0.6590 (3)	0.7760 (3)	0.7846 (2)	0.0627 (11)
N1	0.5479 (2)	0.3954 (4)	0.6536 (2)	0.0349 (9)
N2	0.3668 (3)	0.4189 (4)	0.5009 (3)	0.0411 (10)
H2A	0.384 (3)	0.381 (4)	0.456 (2)	0.049*
H2B	0.333 (3)	0.478 (3)	0.493 (4)	0.049*
N3	0.4048 (2)	0.5170 (4)	0.6337 (2)	0.0348 (9)
C1	0.6196 (3)	0.3347 (5)	0.6661 (3)	0.0510 (13)
H1A	0.6528	0.3520	0.7166	0.061*
C2	0.6469 (4)	0.2478 (5)	0.6083 (4)	0.0574 (14)
H2	0.6969	0.2059	0.6200	0.069*
C3	0.5988 (3)	0.2237 (5)	0.5326 (4)	0.0548 (14)
H3	0.6165	0.1666	0.4914	0.066*
C4	0.5238 (3)	0.2855 (4)	0.5189 (3)	0.0421 (12)
H4	0.4900	0.2698	0.4686	0.051*
C5	0.4994 (3)	0.3717 (4)	0.5812 (3)	0.0304 (10)
C6	0.4200 (3)	0.4393 (4)	0.5716 (3)	0.0307 (10)
C7	0.6314 (3)	0.7709 (5)	0.7064 (3)	0.0423 (12)
C8	0.6594 (5)	0.8661 (6)	0.6421 (4)	0.077 (2)
H8A	0.6782	0.8273	0.5890	0.115*
H8B	0.7047	0.9125	0.6688	0.115*
H8C	0.6132	0.9194	0.6273	0.115*
O4	0.2093 (3)	0.5194 (5)	0.3968 (3)	0.0762 (13)
H4A	0.207 (6)	0.583 (5)	0.364 (5)	0.114*
C9	0.1674 (7)	0.4180 (8)	0.3623 (6)	0.105 (3)
H9A	0.1766	0.3505	0.4032	0.126*
H9B	0.1927	0.3961	0.3066	0.126*
C10	0.0799 (7)	0.4315 (9)	0.3466 (8)	0.146 (5)
H10A	0.0541	0.4565	0.4006	0.219*
H10B	0.0563	0.3551	0.3271	0.219*
H10C	0.0698	0.4922	0.3014	0.219*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cd1	0.0343 (3)	0.0403 (3)	0.0260 (3)	0.000	−0.00478 (18)	0.000
O1	0.0355 (19)	0.053 (2)	0.047 (2)	0.0123 (16)	−0.0101 (15)	−0.0073 (16)
O2	0.054 (2)	0.046 (2)	0.0348 (17)	−0.0145 (18)	−0.0026 (14)	−0.0009 (15)
O3	0.089 (3)	0.042 (2)	0.055 (2)	−0.020 (2)	−0.027 (2)	0.0086 (17)
N1	0.036 (2)	0.034 (2)	0.0340 (19)	0.0011 (18)	−0.0032 (16)	−0.0007 (16)
N2	0.043 (2)	0.045 (3)	0.034 (2)	0.005 (2)	−0.0100 (18)	−0.0086 (18)
N3	0.031 (2)	0.040 (2)	0.033 (2)	0.0060 (18)	−0.0039 (15)	−0.0039 (17)
C1	0.039 (3)	0.065 (4)	0.049 (3)	0.013 (3)	−0.012 (2)	−0.008 (3)
C2	0.048 (3)	0.051 (3)	0.073 (4)	0.019 (3)	−0.004 (3)	−0.002 (3)
C3	0.058 (3)	0.048 (3)	0.059 (3)	0.008 (3)	0.008 (3)	−0.009 (3)
C4	0.046 (3)	0.041 (3)	0.039 (2)	0.004 (2)	−0.001 (2)	−0.010 (2)
C5	0.035 (2)	0.028 (2)	0.028 (2)	−0.003 (2)	0.0008 (18)	0.0048 (17)
C6	0.031 (2)	0.035 (2)	0.026 (2)	−0.003 (2)	0.0000 (17)	0.0072 (18)
C7	0.043 (3)	0.046 (3)	0.038 (3)	−0.001 (2)	−0.001 (2)	−0.006 (2)
C8	0.097 (5)	0.075 (5)	0.057 (4)	−0.045 (4)	−0.008 (3)	0.020 (3)
O4	0.081 (3)	0.068 (3)	0.079 (3)	−0.001 (3)	−0.021 (2)	0.015 (2)
C9	0.148 (9)	0.080 (6)	0.086 (6)	−0.003 (6)	−0.029 (6)	0.001 (4)
C10	0.139 (10)	0.150 (11)	0.147 (9)	−0.070 (8)	−0.041 (8)	0.044 (7)

Geometric parameters (Å, º)

Cd1—O2	2.288 (3)	C2—C3	1.376 (8)
Cd1—O2^i	2.288 (3)	C3—H3	0.9300
Cd1—N1	2.413 (4)	C3—C4	1.381 (7)
Cd1—N1^i	2.413 (4)	C4—H4	0.9300
Cd1—N3^i	2.315 (3)	C4—C5	1.394 (6)
Cd1—N3	2.315 (3)	C5—C6	1.468 (6)
O1—H1	0.846 (10)	C7—C8	1.498 (7)
O1—N3	1.404 (5)	C8—H8A	0.9600
O2—C7	1.254 (6)	C8—H8B	0.9600
O3—C7	1.244 (5)	C8—H8C	0.9600
N1—C1	1.328 (6)	O4—H4A	0.851 (10)
N1—C5	1.339 (5)	O4—C9	1.388 (10)
N2—H2A	0.851 (10)	C9—H9A	0.9700
N2—H2B	0.847 (10)	C9—H9B	0.9700
N2—C6	1.355 (6)	C9—C10	1.412 (14)
N3—C6	1.291 (6)	C10—H10A	0.9600
C1—H1A	0.9300	C10—H10B	0.9600
C1—C2	1.368 (7)	C10—H10C	0.9600
C2—H2	0.9300
O2—Cd1—O2^i	99.86 (18)	C2—C3—C4	118.9 (5)
O2—Cd1—N1	88.81 (13)	C4—C3—H3	120.5
O2^i—Cd1—N1	163.16 (12)	C3—C4—H4	120.4
O2—Cd1—N1^i	163.16 (12)	C3—C4—C5	119.3 (4)
O2^i—Cd1—N1^i	88.81 (13)	C5—C4—H4	120.4
O2—Cd1—N3^i	96.42 (12)	N1—C5—C4	120.8 (4)
O2—Cd1—N3	97.07 (12)	N1—C5—C6	117.0 (4)
O2^i—Cd1—N3	96.42 (12)	C4—C5—C6	122.2 (4)
O2^i—Cd1—N3^i	97.07 (12)	N2—C6—C5	120.5 (4)
N1^i—Cd1—N1	86.69 (19)	N3—C6—N2	123.3 (4)
N3—Cd1—N1	68.01 (13)	N3—C6—C5	116.1 (4)
N3—Cd1—N1^i	96.27 (13)	O2—C7—C8	116.7 (4)
N3^i—Cd1—N1^i	68.01 (13)	O3—C7—O2	124.9 (5)
N3^i—Cd1—N1	96.27 (13)	O3—C7—C8	118.3 (5)
N3^i—Cd1—N3	159.0 (2)	C7—C8—H8A	109.5
N3—O1—H1	106 (4)	C7—C8—H8B	109.5
C7—O2—Cd1	129.4 (3)	C7—C8—H8C	109.5
C1—N1—Cd1	124.4 (3)	H8A—C8—H8B	109.5
C1—N1—C5	119.2 (4)	H8A—C8—H8C	109.5
C5—N1—Cd1	116.4 (3)	H8B—C8—H8C	109.5
H2A—N2—H2B	119 (5)	C9—O4—H4A	116 (6)
C6—N2—H2A	120 (4)	O4—C9—H9A	108.3
C6—N2—H2B	111 (4)	O4—C9—H9B	108.3
O1—N3—Cd1	124.9 (3)	O4—C9—C10	115.9 (9)
C6—N3—Cd1	122.3 (3)	H9A—C9—H9B	107.4
C6—N3—O1	112.6 (3)	C10—C9—H9A	108.3
N1—C1—H1A	118.5	C10—C9—H9B	108.3
N1—C1—C2	123.1 (4)	C9—C10—H10A	109.5
C2—C1—H1A	118.5	C9—C10—H10B	109.5
C1—C2—H2	120.7	C9—C10—H10C	109.5
C1—C2—C3	118.7 (5)	H10A—C10—H10B	109.5
C3—C2—H2	120.7	H10A—C10—H10C	109.5
C2—C3—H3	120.5	H10B—C10—H10C	109.5
Cd1—O2—C7—O3	17.9 (8)	N1—Cd1—N3—O1	−178.6 (4)
Cd1—O2—C7—C8	−164.0 (4)	N1—Cd1—N3—C6	−3.7 (3)
Cd1—N1—C1—C2	−177.2 (4)	N1^i—Cd1—N3—C6	−87.6 (4)
Cd1—N1—C5—C4	176.5 (3)	N1—C1—C2—C3	1.3 (9)
Cd1—N1—C5—C6	−4.1 (5)	N1—C5—C6—N2	−178.9 (4)
Cd1—N3—C6—N2	−177.2 (3)	N1—C5—C6—N3	0.9 (6)
Cd1—N3—C6—C5	3.0 (5)	N3—Cd1—O2—C7	157.2 (4)
O1—N3—C6—N2	−1.7 (6)	N3^i—Cd1—O2—C7	−38.9 (4)
O1—N3—C6—C5	178.5 (3)	N3^i—Cd1—N1—C1	−13.3 (4)
O2^i—Cd1—O2—C7	59.4 (4)	N3—Cd1—N1—C1	−178.9 (4)
O2^i—Cd1—N1—C1	−155.5 (4)	N3^i—Cd1—N1—C5	169.5 (3)
O2—Cd1—N1—C1	83.0 (4)	N3—Cd1—N1—C5	3.9 (3)
O2—Cd1—N1—C5	−94.2 (3)	N3^i—Cd1—N3—O1	137.7 (3)
O2^i—Cd1—N1—C5	27.3 (6)	N3^i—Cd1—N3—C6	−47.4 (3)
O2^i—Cd1—N3—O1	8.1 (4)	C1—N1—C5—C4	−0.8 (7)
O2—Cd1—N3—O1	−92.8 (3)	C1—N1—C5—C6	178.6 (4)
O2^i—Cd1—N3—C6	−177.1 (4)	C1—C2—C3—C4	−1.7 (9)
O2—Cd1—N3—C6	82.1 (4)	C2—C3—C4—C5	0.9 (8)
N1—Cd1—O2—C7	−135.1 (4)	C3—C4—C5—N1	0.4 (7)
N1^i—Cd1—O2—C7	−60.6 (6)	C3—C4—C5—C6	−179.0 (4)
N1^i—Cd1—N1—C1	−80.8 (4)	C4—C5—C6—N2	0.5 (6)
N1^i—Cd1—N1—C5	102.1 (3)	C4—C5—C6—N3	−179.7 (4)
N1^i—Cd1—N3—O1	97.6 (3)	C5—N1—C1—C2	−0.1 (8)

Symmetry code: (i) −x+1, y, −z+3/2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···O3^i	0.85 (1)	1.86 (4)	2.600 (5)	145 (6)
N2—H2A···O2^ii	0.85 (1)	2.20 (2)	3.040 (5)	169 (5)
N2—H2B···O4	0.85 (1)	2.45 (4)	3.113 (6)	136 (5)
O4—H4A···O3^iii	0.85 (1)	2.09 (3)	2.903 (5)	161 (8)

Symmetry codes: (i) −x+1, y, −z+3/2; (ii) −x+1, −y+1, −z+1; (iii) x−1/2, −y+3/2, z−1/2.