N′-[(E)-1-(2-Fluoro­phen­yl)ethyl­idene]pyridine-4-carbohydrazide

P B Sreeja; M Sithambaresan; N Aiswarya; M R Prathapachandra Kurup

doi:10.1107/S1600536814007545

. 2014 Apr 9;70(Pt 5):o532–o533. doi: 10.1107/S1600536814007545

N′-[(E)-1-(2-Fluorophenyl)ethylidene]pyridine-4-carbohydrazide

P B Sreeja ^a, M Sithambaresan ^b,^*, N Aiswarya ^c, M R Prathapachandra Kurup ^c

PMCID: PMC4011257 PMID: 24860344

Abstract

The title compound, C₁₄H₁₂FN₃O, adopts an E conformation with respect to the azomethine bond. The pyridyl and fluorobenzene rings make dihedral angles of 38.58 (6) and 41.61 (5)° respectively with the central C(=O)N₂CC unit, resulting in a non-planar molecule. The intermolecular interactions comprise two classical N—H⋯O and N—H⋯N hydrogen bonds and four non-classical C—H⋯O and C—H⋯F hydrogen bonds. These interactions are augmented by a weak π–π interaction between the benzene and pyridyl rings of neighbouring molecules, with a centroid–centroid distance of 3.9226 (10) Å. This leads to a three-dimensional supramolecular assembly in the crystal system. The F atom is disordered over two sites in a 0.559 (3): 0.441 (3) ratio, through a 180° rotation of the fluorobenzene ring.

Related literature

For biological properties of hydrazones, see: Kahwa et al. (1986 ▶); Santos et al. (2001 ▶); Rollas & Kucukguzel (2007 ▶). For the synthesis of related compounds, see: Mangalam & Kurup (2011 ▶). For related structures, see: Sreeja et al. (2013 ▶, 2014 ▶). graphic file with name e-70-0o532-scheme1.jpg

Experimental

Crystal data

C₁₄H₁₂FN₃O
M _r = 257.27
Monoclinic,
a = 8.2649 (6) Å
b = 19.2127 (14) Å
c = 8.0554 (5) Å
β = 99.244 (3)°
V = 1262.51 (15) Å³
Z = 4
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 296 K
0.35 × 0.30 × 0.25 mm

Data collection

Bruker Kappa APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2004 ▶) T _min = 0.965, T _max = 0.976
9610 measured reflections
3137 independent reflections
2262 reflections with I > 2σ(I)
R _int = 0.030

Refinement

R[F ² > 2σ(F ²)] = 0.048
wR(F ²) = 0.152
S = 1.04
3113 reflections
179 parameters
1 restraint
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.24 e Å⁻³
Δρ_min = −0.21 e Å⁻³

Data collection: APEX2 (Bruker, 2004 ▶); cell refinement: APEX2 and SAINT (Bruker, 2004 ▶); data reduction: SAINT and XPREP (Bruker, 2004 ▶); 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, 2012 ▶) and DIAMOND (Brandenburg, 2010 ▶); software used to prepare material for publication: SHELXL97 and publCIF (Westrip, 2010 ▶).

Supplementary Material

Crystal structure: contains datablock(s) Global, I. DOI: 10.1107/S1600536814007545/fj2669sup1.cif

e-70-0o532-sup1.cif^{(21.5KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536814007545/fj2669Isup2.hkl

e-70-0o532-Isup2.hkl^{(152.8KB, hkl)}

Click here for additional data file.^{(5KB, cml)}

Supporting information file. DOI: 10.1107/S1600536814007545/fj2669Isup3.cml

CCDC reference: 995414

Additional supporting information: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H2′⋯N1ⁱ	0.87 (1)	2.45 (1)	3.1420 (15)	137 (1)
N2—H2′⋯O1ⁱ	0.87 (1)	2.38 (1)	3.1777 (15)	154 (2)
C8—H8C⋯F1ⁱ	0.96	2.46	3.1603 (19)	129
C8—H8C⋯O1ⁱ	0.96	2.58	3.0680 (13)	112
C13—H13⋯F1ⁱⁱ	0.93	2.34	3.238 (2)	161
C14—H14⋯O1ⁱ	0.93	2.50	3.1849 (19)	131

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

Acknowledgments

PBS thanks the Center for Research, Christ University, for financial assistance. MRPK thanks the University Grants Commission, New Delhi, for a UGC–BSR one-time grant to faculty. The authors thank the Sophisticated Analytical Instruments Facility, Cochin University of Science & Technology, for collection of the diffraction data.

supplementary crystallographic information

1. Comment

The chemistry of Schiff bases has attracted a great deal of interest in recent years. These compounds play an important role in the development of various proteins and enzymes (Kahwa et al., 1986; Santos et al., 2001). A number of hydrazones derived from isoniazid were reported to be active antitubercular agents and were found to be less toxic than isoniazid (Rollas & Kucukguzel, 2007). In this paper we report the synthesis and crystal structure of the title compound.

The molecule crystallizes in monoclinic space group P2₁/c. The compound adopts an E configuration with respect to the azomethine olefinic bond whilst the C8 and N2 atoms are in Z configuration with respect to the same bond with torsion angles of -177.77 (8) of and 2.13 (14)° respectively (Fig. 1). The ketonic O and the azomethine N are also cis to each other with a torsion angle of 1.4 (2)°. The molecule exists in the amido form with a C9=O1 bond length of 1.2208 (16) Å which is very close to the reported C=O bond length of a similar structure (Sreeja et al., 2013). The pyridyl ring and the fluorophenyl ring make a dihedral angle of 38.58 (6) and 41.61 (5)° with the C(=O)N₂CC central unit making the molecule non-planar.

There exist two classical N–H···O and N–H···N hydrogen bonding interactions with D···A distances of 3.1777 (15) and 3.1419 (15) Å respectively (Table 1). In addition to this, there are four non-classical C–H···O and C–H···F H bonding interactions present with D···A distances of 3.1603 (19), 3.0680 (13), 3.238 (2) and 3.1849 (19) Å connecting various adjacent molecules together with the main molecule (Fig. 2). The hydrogen atoms at N2 and C8 form bifurcated hydrogen bonds with O1 & N1 and F1 and O1 respectively (Fig. 2). A weak π···π interaction between the phenyl and the pyridyl ring of the neighbouring molecules also supports to form a three-dimensional supramolecular assembly together with the dominant H bonding interactions with a centroid-centroid distance of 3.9226 (10) Å (Fig. 2). Fig. 3 shows the packing of the molecules by means of hydrogen bonding and π–π interactions along a axis.

Through a 180° rotation of the fluorophenyl ring, the fluorine atom F1 is disordered over two sites in a ratio of 56.0 (1):44.0 (1). Similar instances of positional disorder had been previously reported (Sreeja et al., 2014).

2. Experimental

The title compound was prepared by adapting a reported procedure (Mangalam & Kurup, 2011). Methanolic solutions of pyridine-4-carbohydrazide (0.137 g, 1 mmol) and 1-(2-fluorophenyl)ethanone (0.138 g, 1 mmol) was refluxed, in presence of a few drops of glacial acetic acid for 6 h. On cooling the reactant media, colourless crystals of hydrazones were separated out. The crystals were filtered and washed with minimum quantity of methanol and dried over P₄O₁₀in vacuo. Good quality block shaped crystals suitable for X-ray analysis, were obtained from methanolic solution by slow evaporation.