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ISSN: 2414-3146

1,4-Bis(2-nitro­benz­yl)piperazine

aDepartment of Chemistry & Biochemistry, Central Connecticut State University, 1619 Stanley Street, New Britain, CT 06053, USA
*Correspondence e-mail: crundwellg@ccsu.edu

Edited by W. T. A. Harrison, University of Aberdeen, Scotland (Received 28 October 2019; accepted 29 October 2019; online 5 November 2019)

The title compound, C18H20N4O4, was synthesized via the base-assisted reaction of piperazine and 2-nitro­benyl bromide in toluene: the complete mol­ecule is generated by a crystallographic inversion centre in the solid state.

3D view (loading...)
[Scheme 3D1]
Chemical scheme
[Scheme 1]

Structure description

The title compound, C18H20N4O4, has been previously studied by Schlager et al. (1996[Schlager, O., Wieghardt, K., Rufińska, A. & Nuber, B. (1996). J. Chem. Soc. Dalton Trans. pp. 1659-1668.]) and Cameron & Fréchet (1991[Cameron, J. F. & Fréchet, J. M. J. (1991). J. Am. Chem. Soc. 113, 4303-4313.]). In the solid state, the complete mol­ecule is generated by a crystallographic inversion center and the exocyclic N—C bonds have equatorial orientations (bond-angle sum for N1 = 332.4°). The nitro group makes a torsion angle of 45.36 (6)° with its attached C4–C9 phenyl ring. All bond lengths and angles fall within expected values. The mol­ecular structure is shown in Fig. 1[link] and a view of the unit-cell packing along [100] is shown in Fig. 2[link]. No directional inter­molecular inter­actions beyond normal van der Waals contacts could be identified in the extended structure.

[Figure 1]
Figure 1
The mol­ecular structure of the title compound with displacement ellipsoids drawn at the 50% probability level. Unlabelled atoms are generated by the symmetry operation (1 − x, −y, −z) and H atoms are omitted for clarity.
[Figure 2]
Figure 2
A view approximately along [100] of the unit-cell packing.

Synthesis and crystallization

1,4-Bis(2-nitro­benz­yl)piperazine was made according to the published method of Schlager et al. (1996[Schlager, O., Wieghardt, K., Rufińska, A. & Nuber, B. (1996). J. Chem. Soc. Dalton Trans. pp. 1659-1668.]). In an Erlenmeyer flask placed in an 60°C oil bath, 40 mmol (3.45 g) of 1,4-di­aza­cyclo­hexane was added to 100 ml of toluene with stirring. To that solution, 80 mmol (17.3 g) of 2-nitro­benzyl bromide was added. Once dissolved, 90 mmol of powdered KOH (4.98 g) were slowly added with stirring. The mixture was allowed to stir overnight in the oil bath. Upon removal from the oil bath and subsequent cooling, large block-like yellow crystals of the title compound formed. The title compound melts at 409 K. 1H NMR data (Schlager et al., 1996[Schlager, O., Wieghardt, K., Rufińska, A. & Nuber, B. (1996). J. Chem. Soc. Dalton Trans. pp. 1659-1668.]) and FTIR data (Cameron & Fréchet, 1991[Cameron, J. F. & Fréchet, J. M. J. (1991). J. Am. Chem. Soc. 113, 4303-4313.]) are in agreement with published values.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 1[link]. Reflections affected by the beam stop were omitted from the refinement.

Table 1
Experimental details

Crystal data
Chemical formula C18H20N4O4
Mr 356.38
Crystal system, space group Monoclinic, P21/c
Temperature (K) 293
a, b, c (Å) 6.0338 (3), 12.9814 (6), 11.4890 (5)
β (°) 91.185 (4)
V3) 899.71 (7)
Z 2
Radiation type Mo Kα
μ (mm−1) 0.10
Crystal size (mm) 0.41 × 0.40 × 0.22
 
Data collection
Diffractometer Oxford Diffraction Xcalibur, Sapphire3
Absorption correction Multi-scan (CrysAlis PRO; Oxford Diffraction, 2009[Oxford Diffraction (2009). CrysAlis CCD, CrysAlis RED and CrysAlis PRO. Oxford Diffraction Ltd, Yarnton, England.])
Tmin, Tmax 0.801, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections 22354, 3335, 2339
Rint 0.029
(sin θ/λ)max−1) 0.779
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.056, 0.153, 1.03
No. of reflections 3335
No. of parameters 118
H-atom treatment H-atom parameters constrained
Δρmax, Δρmin (e Å−3) 0.19, −0.21
Computer programs: CrysAlis CCD and CrysAlis RED (Oxford Diffraction, 2009[Oxford Diffraction (2009). CrysAlis CCD, CrysAlis RED and CrysAlis PRO. Oxford Diffraction Ltd, Yarnton, England.]), SHELXS2014 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]), SHELXL2014 (Sheldrick, 2015[Sheldrick, G. M. (2015). Acta Cryst. C71, 3-8.]), ORTEP-3 for Windows (Farrugia, 2012[Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849-854.]) and OLEX2 (Bourhis et al., 2015[Bourhis, L. J., Dolomanov, O. V., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2015). Acta Cryst. A71, 59-75.]).

Structural data


Computing details top

Data collection: CrysAlis CCD (Oxford Diffraction, 2009); cell refinement: CrysAlis RED (Oxford Diffraction, 2009); data reduction: CrysAlis RED (Oxford Diffraction, 2009); program(s) used to solve structure: SHELXS2014 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: OLEX2 (Bourhis et al., 2015).

1,4-Bis(2-nitrobenzyl)piperazine top
Crystal data top
C18H20N4O4F(000) = 376.1911
Mr = 356.38Dx = 1.315 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
a = 6.0338 (3) ÅCell parameters from 5355 reflections
b = 12.9814 (6) Åθ = 4.8–31.0°
c = 11.4890 (5) ŵ = 0.10 mm1
β = 91.185 (4)°T = 293 K
V = 899.71 (7) Å3Block, yellow
Z = 20.41 × 0.40 × 0.22 mm
Data collection top
Oxford Diffraction Xcalibur, Sapphire3
diffractometer
3335 independent reflections
Radiation source: Enhance (Mo) X-ray Source2339 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.029
Detector resolution: 16.1790 pixels mm-1θmax = 33.6°, θmin = 4.7°
ω scansh = 99
Absorption correction: multi-scan
(CrysAlis PRO; Oxford Diffraction, 2009)
k = 1919
Tmin = 0.801, Tmax = 1.000l = 1717
22354 measured reflections
Refinement top
Refinement on F2Primary atom site location: iterative
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.056Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.153H-atom parameters constrained
S = 1.03 w = 1/[σ2(Fo2) + (0.0652P)2 + 0.1367P]
where P = (Fo2 + 2Fc2)/3
3335 reflections(Δ/σ)max < 0.001
118 parametersΔρmax = 0.19 e Å3
0 restraintsΔρmin = 0.21 e Å3
Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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.

H atoms were included in calculated positions with C–H = 0.93–0.97 Å and were included in the refinement in the riding motion approximation with Uiso = 1.2Ueq(carrier).

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O10.40223 (19)0.01928 (9)0.36223 (11)0.0757 (3)
O20.7134 (2)0.06112 (8)0.37260 (12)0.0810 (4)
N10.50057 (15)0.06204 (8)0.10262 (8)0.0423 (2)
N20.6030 (2)0.01681 (8)0.35741 (9)0.0543 (3)
C10.29557 (18)0.01964 (11)0.05348 (10)0.0479 (3)
H1A0.22840.06900.00000.058*
H1B0.19210.00670.11530.058*
C20.65771 (19)0.07935 (10)0.01003 (10)0.0478 (3)
H2A0.79490.10670.04300.057*
H2B0.59750.12970.04440.057*
C30.4604 (2)0.15692 (11)0.16799 (11)0.0538 (3)
H3A0.32720.14920.21300.065*
H3B0.43780.21370.11420.065*
C40.6537 (2)0.18024 (9)0.24814 (10)0.0460 (3)
C50.7236 (2)0.11288 (9)0.33597 (10)0.0444 (3)
C60.9076 (2)0.13108 (11)0.40618 (12)0.0582 (3)
H60.94920.08400.46360.070*
C71.0285 (3)0.21903 (12)0.39046 (15)0.0669 (4)
H71.15130.23260.43820.080*
C80.9686 (3)0.28655 (12)0.30476 (15)0.0688 (4)
H81.05250.34570.29340.083*
C90.7835 (3)0.26779 (10)0.23431 (12)0.0609 (4)
H90.74520.31490.17640.073*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0701 (7)0.0770 (8)0.0805 (8)0.0093 (6)0.0174 (6)0.0004 (6)
O20.1077 (9)0.0464 (6)0.0885 (8)0.0106 (6)0.0089 (7)0.0041 (5)
N10.0397 (4)0.0547 (6)0.0325 (4)0.0097 (4)0.0008 (3)0.0032 (4)
N20.0721 (7)0.0484 (6)0.0422 (5)0.0029 (5)0.0009 (5)0.0028 (4)
C10.0367 (5)0.0678 (8)0.0394 (5)0.0076 (5)0.0042 (4)0.0029 (5)
C20.0422 (5)0.0606 (7)0.0407 (5)0.0005 (5)0.0026 (4)0.0008 (5)
C30.0590 (7)0.0590 (7)0.0433 (6)0.0228 (6)0.0049 (5)0.0061 (5)
C40.0560 (6)0.0437 (6)0.0384 (5)0.0127 (5)0.0029 (5)0.0056 (4)
C50.0520 (6)0.0414 (5)0.0400 (5)0.0076 (5)0.0005 (4)0.0061 (4)
C60.0649 (8)0.0552 (7)0.0540 (7)0.0142 (6)0.0142 (6)0.0113 (6)
C70.0583 (8)0.0660 (9)0.0761 (10)0.0030 (7)0.0061 (7)0.0261 (8)
C80.0742 (9)0.0568 (8)0.0764 (10)0.0126 (7)0.0212 (8)0.0227 (7)
C90.0864 (10)0.0461 (7)0.0507 (7)0.0066 (7)0.0140 (7)0.0015 (5)
Geometric parameters (Å, º) top
O1—N21.2143 (15)C3—H3B0.9700
O2—N21.2218 (15)C3—C41.5015 (17)
N1—C11.4570 (15)C4—C51.3941 (16)
N1—C21.4570 (14)C4—C91.3912 (19)
N1—C31.4653 (15)C5—C61.3792 (17)
N2—C51.4673 (16)C6—H60.9300
C1—H1A0.9700C6—C71.369 (2)
C1—H1B0.9700C7—H70.9300
C1—C2i1.5072 (18)C7—C81.361 (2)
C2—C1i1.5072 (18)C8—H80.9300
C2—H2A0.9700C8—C91.388 (2)
C2—H2B0.9700C9—H90.9300
C3—H3A0.9700
C1—N1—C2109.60 (9)H3A—C3—H3B108.1
C1—N1—C3111.61 (9)C4—C3—H3A109.6
C2—N1—C3111.20 (10)C4—C3—H3B109.6
O1—N2—O2123.83 (13)C5—C4—C3122.48 (12)
O1—N2—C5118.94 (11)C9—C4—C3121.77 (12)
O2—N2—C5117.19 (12)C9—C4—C5115.62 (12)
N1—C1—H1A109.6C4—C5—N2120.72 (11)
N1—C1—H1B109.6C6—C5—N2116.33 (11)
N1—C1—C2i110.12 (9)C6—C5—C4122.95 (12)
H1A—C1—H1B108.2C5—C6—H6120.3
C2i—C1—H1A109.6C7—C6—C5119.36 (14)
C2i—C1—H1B109.6C7—C6—H6120.3
N1—C2—C1i110.67 (10)C6—C7—H7120.0
N1—C2—H2A109.5C8—C7—C6119.91 (14)
N1—C2—H2B109.5C8—C7—H7120.0
C1i—C2—H2A109.5C7—C8—H8119.8
C1i—C2—H2B109.5C7—C8—C9120.48 (14)
H2A—C2—H2B108.1C9—C8—H8119.8
N1—C3—H3A109.6C4—C9—H9119.2
N1—C3—H3B109.6C8—C9—C4121.67 (14)
N1—C3—C4110.45 (9)C8—C9—H9119.2
Symmetry code: (i) x+1, y, z.
 

Acknowledgements

This research was funded by a CCSU–AAUP research grant.

References

First citationBourhis, L. J., Dolomanov, O. V., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2015). Acta Cryst. A71, 59–75.  Web of Science CrossRef IUCr Journals Google Scholar
First citationCameron, J. F. & Fréchet, J. M. J. (1991). J. Am. Chem. Soc. 113, 4303–4313.  CrossRef CAS Web of Science Google Scholar
First citationFarrugia, L. J. (2012). J. Appl. Cryst. 45, 849–854.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationOxford Diffraction (2009). CrysAlis CCD, CrysAlis RED and CrysAlis PRO. Oxford Diffraction Ltd, Yarnton, England.  Google Scholar
First citationSchlager, O., Wieghardt, K., Rufińska, A. & Nuber, B. (1996). J. Chem. Soc. Dalton Trans. pp. 1659–1668.  CSD CrossRef Web of Science Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSheldrick, G. M. (2015). Acta Cryst. C71, 3–8.  Web of Science CrossRef IUCr Journals Google Scholar

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