Bis{2-[(2,4-dimethyl­phen­yl)imino­meth­yl]pyridine-κ²N,N′}bis­(thio­cyanato-κN)cadmium

The title compound, [Cd(NCS)₂(C₁₄H₁₄N₂)₂], features crystallographic inversion symmetry with the Cd^II ion located on a centre of inversion. The Cd^II ion is six-coordinated in a slightly distorted octa­hedral geometry with the thiocyanate anions in axial positions. The angle between the benzene and pyridine rings is 69.64 (9)°. An inter­molecular C—H...S hydrogen bond stabilizes the crystal structure.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.025
• wR factor = 0.075
• Data-to-parameter ratio = 22.2

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT934_ALERT_3_B Number of (Iobs-Icalc)/SigmaW .gt. 10 Outliers .          1

Alert level C
PLAT230_ALERT_2_C Hirshfeld Test Diff for    S1     --  C15     ..        6.5 su
PLAT241_ALERT_2_C Check High      Ueq as Compared to Neighbors for         N3
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for        C15
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.600          5
PLAT912_ALERT_4_C Missing # of FCF Reflections Above STh/L=  0.600         17
PLAT913_ALERT_3_C Missing # of Very Strong Reflections in FCF ....          1

Alert level G
PLAT005_ALERT_5_G No _iucr_refine_instructions_details in CIF ....          ?
PLAT006_ALERT_5_G Note: Extinction Parameter Refined  =  0.0048             !
PLAT380_ALERT_4_G Check Incorrectly? Oriented X(sp2)-Methyl Moiety         C8

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

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   3 ALERT type 2 Indicator that the structure model may be wrong or deficient
   3 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion
   2 ALERT type 5 Informative message, check

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S1. Comment

Nitrogen donor ligands particularly Schiff bases have been a subject of interest for chemists. Schiff bases form a class of compounds with azomethine group, which are usually synthesized from the condensation of primary amines and active carbonyl groups by elimination of water molecule. The Schiff bases and their metal complexes are important class of compounds in medicinal and pharmaceutical field (Azza & Abu, 2006; Dudek & Dudek, 1966; Pandeya et al., 1999; Panneerselvam et al., 2005; Singh et al., 2006; Sridhar et al. 2001; Mladenova et al., 2002; Walsh et al., 1996).

Following our studies on the synthesis and structural determination of transition metal complexes with iminopyridine ligands by X-ray crystallography (Talei Bavil Olyai et al., 2008; Talei Bavil Olyai, Gholami Troujeni et al., 2010; Talei Bavil Olyai, Razzaghi Fard et al., 2010; Fallah Nejad et al., 2010; Loni et al., 2011). We report herein the crystal structure of the title compound, a new cadmium(II) complex, (1), derived from the Schiff base ligand and thiocyanate. The title complex was synthesized by the reaction of Cd(CH₃COO)₂.2H₂O with 2-[(2,4-dimethylphenyl)iminomethyl]- pyridine and KSCN in methanol as solution.

In the crystal structure of the title compound (Fig. 1), the cadmium(II) ion is six-coordinated in distorted octahedral geometry. Two Schiff base ligands coordinate the cadmium center as a bidentate ligand through the nitrogen atoms of imine group and pyridine ring. The Cd(II) ion is soft acidic metal center. According to symbiosis logic of Jorgensen, coordination of four electronegative nitrogen atoms of iminopyridine ligands have increased hardness of the cadmium ion and makes it a hard Lewis acid. Therefore, the Cd(II) ion prefers to bond to nitrogen atom of the ambidentate thiocyanate ligand.

The Cd—N_thiocyanate distances [2.3032 (17) Å] are notably shorter than the Cd—N_imine distances [2.3529 (1) Å] and Cd—N_pyridine [2.3708 (14) Å] (Table 1). The two imine linkages, C9—N1 [1.268 (2) Å], are both short, which is in the accepted range for carbon-nitrogen double bonds. Four donor nitrogen atoms of the iminopyridine ligands are absolutely planar with the Cadmium(II). In the title compound, coordination plane (containing the ligands backbone and the cadmium atom), and two thiocyanate ions are trans to each other. The angle between phenyl and pyridine rings are 69.64 (9) Å. In the crystal structure of the title compound an intermolecular C—H···S hydrogen bond (Table 2) stabilize crystal structure.

Related literature

For the medicinal and pharmaceutical application of Schiff base compounds, see: Azza & Abu (2006); Dudek & Dudek (1966); Pandeya et al. (1999); Panneerselvam et al. (2005); Singh et al. (2006); Sridhar et al. (2001); Mladenova et al. (2002); Walsh et al. (1996). For the crystal structure of iminopyridine complexes, see: Talei Bavil Olyai et al. (2008); Talei Bavil Olyai, Gholami Troujeni et al. (2010); Talei Bavil Olyai, Razzaghi Fard et al. (2010); Fallah Nejad et al. (2010); Loni et al. (2011).

S2. Experimental

For the preparation of the title compound, a mixed solution of 2-[(2,4-dimethylphenyl)-iminomethyl]-pyridine (0.420 g, 2.00 mmol) and KSCN (0.195 g 2.00 mmol) in methanol (10 ml) was added slowly to a solution of Cd(CH₃COO)₂.2H₂O (0.267 g, 1.00 mmol) in methanol (10 ml) and the resulting yellow solution was stirred for 45 min at room temperature, and then left to evaporate slowly at 3–5°C. After twenty days, yellow crystals of the title compound were isolated (yield; 0.426 g, 74.2%, m. p. 453 K).

S3. Refinement

All H atoms were positioned geometrically and refined as riding atoms with C—H=0.93(CH) and 0.96(CH₃) Å and with U_iso(H) = 1.2 (1.5 for methyl)U_eq(C).

Computing details

Data collection: X-AREA (Stoe & Cie, 2005); cell refinement: X-AREA (Stoe & Cie, 2005); data reduction: X-AREA (Stoe & Cie, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures

	Fig. 1. The molecular structure of the title molecule, with the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level [symmetry code:(a)-x + 1, -y, -z + 1].
	Fig. 2. Packing diagram of the title compound showing intermolecular C—H···S hydrogen bonding.

Bis{2-[(2,4-dimethylphenyl)iminomethyl]pyridine- κ²N,N'}bis(thiocyanato-κN)cadmium

Crystal data

[Cd(NCS)2(C14H14N2)2]	F(000) = 1320.0
Mr = 649.13	Dx = 1.445 Mg m^−3
Orthorhombic, Pbcn	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2n 2ab	Cell parameters from 4016 reflections
a = 11.285 (2) Å	θ = 2.3–29.2°
b = 15.048 (3) Å	µ = 0.90 mm^−1
c = 17.576 (4) Å	T = 298 K
V = 2984.7 (10) Å^3	Block, yellow
Z = 4	0.45 × 0.4 × 0.4 mm

Data collection

Stoe IPDS II diffractometer	4016 independent reflections
Radiation source: fine-focus sealed tube	2589 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.028
Detector resolution: 0.15 mm pixels mm^-1	θmax = 29.2°, θmin = 2.3°
rotation method scans	h = −15→13
Absorption correction: numerical shape of crystal determined optically	k = −20→18
Tmin = 0.406, Tmax = 0.430	l = −20→24
12952 measured reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.025	H-atom parameters constrained
wR(F^2) = 0.075	w = 1/[σ^2(Fo^2) + (0.0406P)^2 + 0.0706P] where P = (Fo^2 + 2Fc^2)/3
S = 1.00	(Δ/σ)max = 0.001
4016 reflections	Δρmax = 0.20 e Å^−3
181 parameters	Δρmin = −0.39 e Å^−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0048 (4)

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	0.0000	0.5000	0.05113 (8)
S1	0.81414 (5)	0.10677 (4)	0.32032 (3)	0.08019 (19)
N1	0.40527 (12)	0.08917 (9)	0.40838 (7)	0.0506 (3)
N2	0.56541 (13)	0.09386 (10)	0.59987 (8)	0.0522 (3)
N3	0.66504 (15)	0.03255 (13)	0.42813 (10)	0.0687 (4)
C1	0.40926 (15)	0.18477 (11)	0.40648 (9)	0.0484 (4)
C2	0.34254 (16)	0.23310 (12)	0.45844 (9)	0.0537 (4)
C3	0.35215 (18)	0.32527 (12)	0.45528 (11)	0.0607 (5)
H3	0.3075	0.3589	0.4892	0.073*
C4	0.42425 (17)	0.36928 (12)	0.40456 (11)	0.0603 (5)
C5	0.49090 (17)	0.31881 (14)	0.35509 (12)	0.0645 (5)
H5	0.5413	0.3469	0.3208	0.077*
C6	0.48400 (16)	0.22711 (14)	0.35565 (11)	0.0585 (5)
H6	0.5295	0.1939	0.3219	0.070*
C7	0.2607 (2)	0.18931 (16)	0.51445 (12)	0.0771 (6)
H7A	0.2006	0.1569	0.4875	0.116*
H7B	0.2241	0.2338	0.5457	0.116*
H7C	0.3051	0.1492	0.5459	0.116*
C8	0.4294 (2)	0.46981 (15)	0.40349 (16)	0.0888 (7)
H8A	0.3775	0.4931	0.4419	0.133*
H8B	0.4049	0.4911	0.3545	0.133*
H8C	0.5090	0.4890	0.4134	0.133*
C9	0.37889 (16)	0.04762 (12)	0.34795 (10)	0.0560 (4)
H9	0.3556	0.0800	0.3054	0.067*
C10	0.61622 (16)	0.04953 (12)	0.65736 (9)	0.0530 (4)
C11	0.66386 (19)	0.09220 (14)	0.71998 (12)	0.0700 (5)
H11	0.6992	0.0597	0.7588	0.084*
C12	0.6583 (2)	0.18377 (15)	0.72401 (13)	0.0756 (6)
H12	0.6895	0.2139	0.7656	0.091*
C13	0.6062 (2)	0.22922 (14)	0.66575 (12)	0.0698 (5)
H13	0.6016	0.2909	0.6670	0.084*
C14	0.56032 (18)	0.18261 (13)	0.60500 (11)	0.0619 (5)
H14	0.5243	0.2142	0.5658	0.074*
C15	0.72622 (16)	0.06333 (12)	0.38293 (10)	0.0522 (4)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cd1	0.06666 (13)	0.05083 (12)	0.03589 (10)	−0.00527 (8)	−0.00409 (7)	0.00119 (7)
S1	0.0866 (4)	0.0912 (4)	0.0628 (3)	−0.0209 (3)	0.0033 (3)	0.0211 (3)
N1	0.0607 (8)	0.0512 (9)	0.0399 (7)	0.0054 (7)	0.0001 (6)	−0.0038 (6)
N2	0.0612 (9)	0.0500 (9)	0.0453 (8)	−0.0035 (7)	0.0000 (6)	−0.0037 (6)
N3	0.0716 (11)	0.0741 (11)	0.0603 (10)	−0.0121 (9)	0.0033 (8)	0.0023 (9)
C1	0.0585 (10)	0.0476 (10)	0.0390 (8)	0.0059 (7)	−0.0049 (7)	−0.0004 (7)
C2	0.0597 (10)	0.0555 (11)	0.0459 (9)	0.0052 (8)	0.0011 (8)	−0.0029 (8)
C3	0.0684 (11)	0.0553 (11)	0.0584 (10)	0.0112 (9)	−0.0002 (9)	−0.0086 (9)
C4	0.0667 (11)	0.0533 (11)	0.0609 (11)	−0.0013 (9)	−0.0121 (9)	0.0007 (9)
C5	0.0689 (12)	0.0657 (13)	0.0590 (11)	−0.0056 (10)	0.0020 (9)	0.0101 (10)
C6	0.0706 (12)	0.0607 (12)	0.0442 (9)	0.0069 (9)	0.0049 (8)	0.0000 (9)
C7	0.0892 (15)	0.0687 (13)	0.0733 (13)	0.0118 (12)	0.0293 (12)	0.0053 (11)
C8	0.1038 (19)	0.0544 (12)	0.108 (2)	−0.0100 (13)	−0.0139 (15)	0.0021 (13)
C9	0.0691 (11)	0.0571 (12)	0.0418 (9)	0.0060 (9)	−0.0044 (8)	−0.0015 (8)
C10	0.0618 (10)	0.0546 (12)	0.0426 (9)	0.0016 (8)	−0.0012 (8)	−0.0067 (8)
C11	0.0891 (14)	0.0677 (14)	0.0531 (10)	0.0060 (11)	−0.0140 (10)	−0.0143 (10)
C12	0.0940 (16)	0.0691 (15)	0.0636 (11)	−0.0024 (12)	−0.0115 (12)	−0.0225 (11)
C13	0.0852 (14)	0.0517 (11)	0.0727 (13)	−0.0019 (10)	0.0019 (11)	−0.0165 (10)
C14	0.0712 (13)	0.0538 (11)	0.0607 (11)	−0.0017 (9)	−0.0021 (10)	0.0008 (9)
C15	0.0588 (10)	0.0489 (9)	0.0491 (9)	−0.0032 (8)	−0.0094 (8)	0.0014 (8)

Geometric parameters (Å, º)

Cd1—N3^i	2.3032 (17)	C5—C6	1.382 (3)
Cd1—N3	2.3032 (17)	C5—H5	0.9300
Cd1—N1	2.3529 (14)	C6—H6	0.9300
Cd1—N1^i	2.3529 (14)	C7—H7A	0.9600
Cd1—N2^i	2.3708 (14)	C7—H7B	0.9600
Cd1—N2	2.3708 (14)	C7—H7C	0.9600
S1—C15	1.619 (2)	C8—H8A	0.9600
N1—C9	1.268 (2)	C8—H8B	0.9600
N1—C1	1.440 (2)	C8—H8C	0.9600
N2—C10	1.340 (2)	C9—C10^i	1.466 (3)
N2—C14	1.340 (2)	C9—H9	0.9300
N3—C15	1.150 (2)	C10—C11	1.383 (2)
C1—C6	1.384 (3)	C10—C9^i	1.466 (3)
C1—C2	1.389 (2)	C11—C12	1.381 (3)
C2—C3	1.392 (2)	C11—H11	0.9300
C2—C7	1.502 (3)	C12—C13	1.365 (3)
C3—C4	1.377 (3)	C12—H12	0.9300
C3—H3	0.9300	C13—C14	1.378 (3)
C4—C5	1.378 (3)	C13—H13	0.9300
C4—C8	1.514 (3)	C14—H14	0.9300
N3^i—Cd1—N3	180.0	C6—C5—H5	119.5
N3^i—Cd1—N1	97.43 (6)	C5—C6—C1	119.89 (18)
N3—Cd1—N1	82.57 (6)	C5—C6—H6	120.1
N3^i—Cd1—N1^i	82.57 (6)	C1—C6—H6	120.1
N3—Cd1—N1^i	97.43 (6)	C2—C7—H7A	109.5
N1—Cd1—N1^i	180.00 (5)	C2—C7—H7B	109.5
N3^i—Cd1—N2^i	91.58 (6)	H7A—C7—H7B	109.5
N3—Cd1—N2^i	88.42 (6)	C2—C7—H7C	109.5
N1—Cd1—N2^i	72.03 (5)	H7A—C7—H7C	109.5
N1^i—Cd1—N2^i	107.97 (5)	H7B—C7—H7C	109.5
N3^i—Cd1—N2	88.42 (6)	C4—C8—H8A	109.5
N3—Cd1—N2	91.58 (6)	C4—C8—H8B	109.5
N1—Cd1—N2	107.97 (5)	H8A—C8—H8B	109.5
N1^i—Cd1—N2	72.03 (5)	C4—C8—H8C	109.5
N2^i—Cd1—N2	180.0	H8A—C8—H8C	109.5
C9—N1—C1	118.73 (15)	H8B—C8—H8C	109.5
C9—N1—Cd1	113.50 (12)	N1—C9—C10^i	122.43 (16)
C1—N1—Cd1	124.85 (10)	N1—C9—H9	118.8
C10—N2—C14	117.64 (16)	C10^i—C9—H9	118.8
C10—N2—Cd1	113.27 (11)	N2—C10—C11	122.37 (17)
C14—N2—Cd1	129.08 (12)	N2—C10—C9^i	117.69 (15)
C15—N3—Cd1	161.83 (17)	C11—C10—C9^i	119.94 (17)
C6—C1—C2	120.91 (16)	C12—C11—C10	119.1 (2)
C6—C1—N1	119.60 (16)	C12—C11—H11	120.4
C2—C1—N1	119.40 (15)	C10—C11—H11	120.4
C1—C2—C3	116.94 (17)	C13—C12—C11	118.8 (2)
C1—C2—C7	122.30 (17)	C13—C12—H12	120.6
C3—C2—C7	120.73 (17)	C11—C12—H12	120.6
C4—C3—C2	123.43 (18)	C12—C13—C14	119.2 (2)
C4—C3—H3	118.3	C12—C13—H13	120.4
C2—C3—H3	118.3	C14—C13—H13	120.4
C3—C4—C5	117.78 (18)	N2—C14—C13	122.92 (19)
C3—C4—C8	120.7 (2)	N2—C14—H14	118.5
C5—C4—C8	121.5 (2)	C13—C14—H14	118.5
C4—C5—C6	121.01 (19)	N3—C15—S1	179.04 (17)
C4—C5—H5	119.5
N3^i—Cd1—N1—C9	−97.15 (13)	N1—C1—C2—C3	178.39 (16)
N3—Cd1—N1—C9	82.85 (13)	C6—C1—C2—C7	−179.92 (19)
N2^i—Cd1—N1—C9	−7.89 (12)	N1—C1—C2—C7	−3.3 (3)
N2—Cd1—N1—C9	172.11 (12)	C1—C2—C3—C4	−0.7 (3)
N3^i—Cd1—N1—C1	102.54 (13)	C7—C2—C3—C4	−179.06 (19)
N3—Cd1—N1—C1	−77.46 (13)	C2—C3—C4—C5	−0.7 (3)
N2^i—Cd1—N1—C1	−168.21 (13)	C2—C3—C4—C8	179.22 (19)
N2—Cd1—N1—C1	11.79 (13)	C3—C4—C5—C6	1.0 (3)
N3^i—Cd1—N2—C10	79.80 (12)	C8—C4—C5—C6	−178.9 (2)
N3—Cd1—N2—C10	−100.20 (12)	C4—C5—C6—C1	0.0 (3)
N1—Cd1—N2—C10	177.10 (12)	C2—C1—C6—C5	−1.4 (3)
N1^i—Cd1—N2—C10	−2.90 (12)	N1—C1—C6—C5	−178.07 (16)
N3^i—Cd1—N2—C14	−101.74 (16)	C1—N1—C9—C10^i	173.99 (15)
N3—Cd1—N2—C14	78.26 (16)	Cd1—N1—C9—C10^i	12.4 (2)
N1—Cd1—N2—C14	−4.44 (17)	C14—N2—C10—C11	−0.9 (3)
N1^i—Cd1—N2—C14	175.56 (17)	Cd1—N2—C10—C11	177.80 (15)
N1—Cd1—N3—C15	7.1 (5)	C14—N2—C10—C9^i	179.59 (16)
N1^i—Cd1—N3—C15	−172.9 (5)	Cd1—N2—C10—C9^i	−1.76 (19)
N2^i—Cd1—N3—C15	79.2 (5)	N2—C10—C11—C12	0.5 (3)
N2—Cd1—N3—C15	−100.8 (5)	C9^i—C10—C11—C12	−179.9 (2)
C9—N1—C1—C6	−57.6 (2)	C10—C11—C12—C13	−0.2 (3)
Cd1—N1—C1—C6	101.74 (16)	C11—C12—C13—C14	0.3 (3)
C9—N1—C1—C2	125.68 (18)	C10—N2—C14—C13	0.9 (3)
Cd1—N1—C1—C2	−74.95 (18)	Cd1—N2—C14—C13	−177.48 (15)
C6—C1—C2—C3	1.7 (3)	C12—C13—C14—N2	−0.7 (3)

Symmetry code: (i) −x+1, −y, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C12—H12···S1^ii	0.93	2.87	3.591 (2)	136

Symmetry code: (ii) −x+3/2, −y+1/2, z+1/2.