Bis{N 2,N 6-bis­[(pyridin-3-yl)meth­yl]pyridine-2,6-dicarboxamide-κN}bis­(methanol-κO)bis­(thio­cyanato-κN)cobalt(II)

Guang-Rui Yang; Juan Ren; Guo-Ting Li

doi:10.1107/S1600536812020326

. 2012 May 12;68(Pt 6):m765. doi: 10.1107/S1600536812020326

Bis{N ²,N ⁶-bis[(pyridin-3-yl)methyl]pyridine-2,6-dicarboxamide-κN}bis(methanol-κO)bis(thiocyanato-κN)cobalt(II)

Guang-Rui Yang ^a,^*, Juan Ren ^b, Guo-Ting Li ^a

PMCID: PMC3379100 PMID: 22719321

Abstract

In the title compound, [Co(NCS)₂(C₁₉H₁₇N₅O₂)₂(CH₃OH)₂], the Co^II atom lies on an inversion center and is coordinated by two isothiocyanate N atoms, two O atoms of methanol molecules and two pyridine N atoms in a slightly distorted octahedral environment. Intermolecular O—H⋯O and N—H⋯N hydrogen bonds join the complex molecules into layers parallel to the bc plane.

Related literature

For the coordination chemistry of pyridylcarboxamides, see: Thompson (2002 ▶); Wu et al. (2008 ▶). For the architectures of complexes with pyridylcarboxamide ligands and various metal ions, see: Uemura et al. (2002 ▶); Burchell et al. (2006 ▶).

Experimental

Crystal data

[Co(NCS)₂(C₁₉H₁₇N₅O₂)₂(CH₄O)₂]
M _r = 933.93
Monoclinic,
a = 9.6728 (19) Å
b = 17.631 (4) Å
c = 13.041 (3) Å
β = 100.13 (3)°
V = 2189.4 (8) Å³
Z = 2
Mo Kα radiation
μ = 0.55 mm⁻¹
T = 293 K
0.22 × 0.21 × 0.18 mm

Data collection

Siemens SMART CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.892, T _max = 0.914
21676 measured reflections
3803 independent reflections
3435 reflections with I > 2σ(I)
R _int = 0.049

Refinement

R[F ² > 2σ(F ²)] = 0.054
wR(F ²) = 0.101
S = 1.15
3803 reflections
291 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.18 e Å⁻³
Δρ_min = −0.18 e Å⁻³

Data collection: SMART (Siemens, 1996 ▶); cell refinement: SAINT (Siemens, 1996 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812020326/yk2057sup1.cif

e-68-0m765-sup1.cif^{(22.6KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812020326/yk2057Isup2.hkl

e-68-0m765-Isup2.hkl^{(186.4KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Selected bond lengths (Å).

Co1—N6	2.074 (2)
Co1—O3	2.134 (2)
Co1—N4	2.162 (2)

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Table 2. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N3—H3A⋯N5ⁱ	0.88	2.18	2.980 (3)	151
O3—H1⋯O2ⁱⁱ	0.76 (3)	1.94 (3)	2.679 (3)	163 (3)

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

This work was supported by the Natural Science Foundation of China.

supplementary crystallographic information

Comment

Pyridylcarboxamides derived from carboxylic acids form a class of spectacularly multidentate heterocyclic ligands and hold an important position in biochemistry and coordination chemistry (Thompson, 2002; Wu et al., 2008). Over the last decades, several research groups worldwide have provided a wide range of structural motifs from isolated macrocycles, helicates to dynamic porous frameworks based on pyridylcarboxamide ligands (Uemura, et al., 2002; Burchell, et al., 2006). In course of such studies, we synthesized the symmetric multifunctional ligand N²,N⁶-bis((pyridin-3-yl)methyl)pyridine-2,6-dicarboxamide (BPDA) and prepared complexes of BPDA with some metal ions. Here we present the structure of such complex, [Co(BPDA)₂(CH₄O)₂(SCN)₂] (1).

The title compound is a mononuclear complex, where the Co²⁺ ion lies at the inversion center, thus the asymmetric unit consists of Co atom, one BPDA, one methanol molecule, and one SCN^- anion (Fig. 1). In (1) the coordination center is ligated by two isothiocyanato N atoms, two methanol O atoms, and two BPDA acting as monodentate ligands through their pyridyl N atoms. The octahedral coordination environment is slightly distorted, the largest deviation of coordination angles from idealized values are 1.59 (9) °.

Further aggregation of complex molecules is formed by the multiple hydrogen-bonding between the dicarboxamide groups of BPDA (as donors) and the uncoordinated pyridyl groups of other BPDA (as acceptors) as well as between the coordination methanol molecules (as donors) and the dicarboxamide groups of BPDA (as acceptors) (Table 2). Consequently, monomers are linked by O—H···O and N—H···N hydrogen bonds into a two-dimensional network parallel to the bc plane (Fig. 2). The layer structure is stabilized by face-to-face π···π stacking interactions between adjacent central pyridine rings of BPDA with a centroid to centroid distance of 3.793 (2) Å. Notably, that the ligand BPDA in (1) have pseudo-C₂ symmetry and adopts helical conformation with the dihedral angles of the pendant pyridyl groups with the central pyridine ring of 76.1 (3) and 75.6 (3) °, respectively.

Experimental

Synthesis of BPDA ligand. A mixture of 2,6-pyridinedicarboxylic acid (10 g, 60 mmol) and thionyl chloride (75 ml) was heated with reflux for 6 h under anhydrous condition, and then excess thionyl chloride was removed by rotary evaporation. The resulting white solid pyridine-2,6-dicarboyl dichloride was dissolved in dry CH₂Cl₂ (50 ml), to which a solution of 3-(aminomethyl)pyridine (13 g, 120 mmol) and triethylamine (24 ml) in dry CH₂Cl₂ (70 ml) was added dropwise with continuous stirring in an ice-bath. Stirred at room temperature for another hour, the mixture was washed with water (500 ml). The separated organic phase was dried with magnesium sulfate, and the solvent was removed by rotary evaporation. After recrystallization from alcohol/water (2:1), white crystals of BPDA were obtained (Yield: 70%). Selected IR (cm^-1, KBr pellet): 3551(m), 3305(s), 3055(m), 2925(m), 1670(vs), 1593(m), 1542(vs), 1478(m), 1425(m), 1313(m), 1258(m), 1175(m), 1076(m), 1000(s), 864(m), 770(s), 679(m), 614(w).

The title compound (1) was prepared according to the following process. A solution of BPDA (69.4 mg, 0.2 mmol) in DMF (5 ml) was dropwise added into a solution of CoSO₄.6H₂O (28.1 mg, 0.1 mmol) in methanol (5 ml), and then a solution of KSCN (19.4 mg, 0.2 mmol) in methanol (5 ml) was dropwise added into the above mixture. With stirring for 30 minutes, the resulting mixture was filtered. The filtrate was allowed to evaporate at room temperature for two days, and pink crystals were obtain in 48% yield. Selected IR (cm^-1, KBr pellet): 3351(m), 2072(vs), 1670(vs), 1534(vs), 1437(m), 1087(m), 750(m), 709(m).