4-Acetyl­piperazinium picrate

Channappa N Kavitha; Manpreet Kaur; Jerry P Jasinski; Hemmige S Yathirajan

doi:10.1107/S1600536814011726

. 2014 May 31;70(Pt 6):o717–o718. doi: 10.1107/S1600536814011726

4-Acetylpiperazinium picrate

Channappa N Kavitha ^a, Manpreet Kaur ^a, Jerry P Jasinski ^b,^*, Hemmige S Yathirajan ^a

PMCID: PMC4051097 PMID: 24940287

Abstract

In the title salt, C₆H₁₃N₂O⁺·C₆H₂N₃O₇ ⁻ (systematic name: 4-acetylpiperazin-1-ium 2,4,6-trinitrophenolate), the piperazin-1-ium ring has a slightly distorted chair conformation. In the picrate anion, the mean planes of the two o-NO₂ and p-NO₂ groups are twisted with respect to the benzene ring by 15.0 (2), 68.9 (4) and 4.4 (3)°, respectively. In the crystal, N—H⋯O hydrogen bonds are observed, linking the ions into an infinite chain along [010]. In addition, weak cation–anion C—H⋯O intermolecular interactions and a weak π–π stacking interaction between the benzene rings of the anions, with an inter-centroid distance of 3.771 (8) Å, help to stabilize the crystal packing, giving an overall sheet structure lying parallel to (100). Disorder was modelled for one of the O atoms in one of the o-NO₂ groups over two sites with an occupancy ratio of 0.57 (6):0.43 (6).

Related literature

Piperazines and substituted piperazines are important pharmacophores that can be found in many biologically active compounds across a number of different therapeutic areas, see: Berkheij (2005 ▶); Choudhary et al. (2006 ▶); Kharb et al. (2012 ▶); Upadhayaya et al. (2004 ▶). For picric acid salts, see: Hundal et al. (1997 ▶); Szumna et al. (2000 ▶); Colquhoun et al. (1986 ▶). For related structures, see: Kavitha et al. (2013 ▶, 2014 ▶); Loughlin et al. (2003 ▶); Wang & Jia (2008 ▶); Song et al. (2012 ▶). For puckering parameters, see Cremer & Pople (1975 ▶). For standard bond lengths, see: Allen et al. (1987 ▶). graphic file with name e-70-0o717-scheme1.jpg

Experimental

Crystal data

C₆H₁₃N₂O⁺·C₆H₂N₃O₇ ⁻
M _r = 357.29
Monoclinic,
a = 6.6843 (7) Å
b = 11.5971 (12) Å
c = 20.131 (2) Å
β = 90.000 (4)°
V = 1560.5 (3) Å³
Z = 4
Cu Kα radiation
μ = 1.12 mm⁻¹
T = 173 K
0.32 × 0.28 × 0.06 mm

Data collection

Agilent Eos Gemini diffractometer
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2014 ▶) T _min = 0.631, T _max = 1.000
9739 measured reflections
2993 independent reflections
2690 reflections with I > 2σ(I)
R _int = 0.036

Refinement

R[F ² > 2σ(F ²)] = 0.045
wR(F ²) = 0.126
S = 1.10
2993 reflections
238 parameters
H-atom parameters constrained
Δρ_max = 0.27 e Å⁻³
Δρ_min = −0.20 e Å⁻³

Data collection: CrysAlis PRO (Agilent, 2014 ▶); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SUPERFLIP (Palatinus & Chapuis, 2007 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: OLEX2 (Dolomanov et al., 2009 ▶); software used to prepare material for publication: OLEX2.

Supplementary Material

Crystal structure: contains datablock(s) I. DOI: 10.1107/S1600536814011726/zs2300sup1.cif

e-70-0o717-sup1.cif^{(25.7KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536814011726/zs2300Isup2.hkl

e-70-0o717-Isup2.hkl^{(164.4KB, hkl)}

Click here for additional data file.^{(6.4KB, cml)}

Supporting information file. DOI: 10.1107/S1600536814011726/zs2300Isup3.cml

CCDC reference: 1004370

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
N2A—H2AA⋯O1A ⁱ	0.97	1.78	2.7057 (19)	159
N2A—H2AB⋯O1B ⁱⁱ	0.97	1.82	2.7401 (19)	157
C3A—H3AA⋯O5B ⁱ	0.97	2.46	3.333 (2)	150
C3A—H3AB⋯O3B ⁱⁱⁱ	0.97	2.55	3.469 (3)	158
C5A—H5AA⋯O7B ^iv	0.97	2.57	3.365 (2)	139
C5B—H5B⋯O1A	0.93	2.47	3.307 (2)	149

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

Acknowledgments

CNK thanks the University of Mysore for research facilities and also grateful to the Principal, Maharani’s Science College for Women, Mysore, for giving permission to undertake research. JPJ acknowledges the NSF–MRI program (grant No. CHE-1039027) for funds to purchase the X-ray diffractometer.

supplementary crystallographic information

1. Comment

Piperazines and substituted piperazines are important pharmacophores that can be found in many biologically active compounds across a number of different therapeutic areas (Berkheij, 2005) such as antifungal (Upadhayaya et al., 2004), anti-bacterial, anti-malarial and anti-psychotic agents (Choudhary et al., 2006). A valuable insight into recent advances on antimicrobial activity of piperazine derivatives has been reported (Kharb et al., 2012). Also picric acid forms salts which exhibit electrostatic forces, multiple hydrogen bonds (Hundal et al., 1997; Szumna et al., 2000) and π–π stacking interactions (Colquhoun et al., 1986), which improve the quality of the crystalline materials. The supra-molecular structure of molecular adducts of picric acid and piperazine have been reported (Wang & Jia, 2008). The crystal structures of some related compounds, viz., 1-[4-(4-hydroxyphenyl)piperazin-1-yl]ethanone (Kavitha et al., 2013), 3-(Z)-isobutylidene-1-acetylpiperazine-2,5-dione (Loughlin et al. , 2003), piperazine-1,4-diium picrate-piperazine (Wang & Jia, 2008), cinnarizinium picrate (Song et al., 2012) and 1-piperonylpiperazinium picrate (Kavitha et al., 2014) have been reported. In view of the importance of the title compound, C₆H₁₃N₂O⁺. C₆H₂N₃O₇^-, this paper reports its crystal structure.

The title salt crystallizes with one piperazinium cation (A) and a picrate anion (B) in the asymmetric unit (Fig. 1). In the cation, the piperazine ring is in a slightly distorted chair conformation (puckering parameters Q, θ, and φ = 0.569 (2)Å, 178.3 (5)° and 197 (9)°, respectively (Cremer & Pople, 1975). In the picrate anion, the mean planes of the two o-NO₂ groups and the p-NO₂ group are twisted with respect to the phenyl ring plane by 15.0 (2)°, 68.9 (4)° and 4.4 (3)°, respectively. Bond lengths are in normal ranges (Allen et al., 1987). Intermolecular N—H···O hydrogen bonds are observed (Table 1) linking the anions with the cations and other anions forming an infinite one-dimensional chain along [010] (Fig. 2). In addition, weak cation-anion intermolecular C—H···O interactions and a weak π–π stacking interaction between the anionic phenyl rings [inter-centroid distance = 3.771 (8) Å] stabilize the crystal packing and generate a overall two-dimensional sheet structure lying parallel to (100). Disorder was modelled for the O2B oxygen atom in one of the o-NO₂ groups over two sites with an occupancy ratio of 0.57 (6):0.43 (6).

2. Experimental

Picric acid (1.14 g, 0.005 mol) was dissolved in methanol and acetyl piperazine (0.63 ml, 0.005 mol) was added to it with stirring. A yellow precipitate was obtained instantaneously. The precipitate was recrystallized from ethanol by slow evaporation (m.p.: 443–448 K).