organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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1,4-Bis(2-diazo­acet­yl)piperazine

aDepartment of Chemistry, University of Oslo, PO Box 1033 Blindern, N-0315 Oslo, Norway
*Correspondence e-mail: c.h.gorbitz@kjemi.uio.no

(Received 13 May 2013; accepted 8 July 2013; online 13 July 2013)

The asymmetric unit of the title compound, C8H10N6O2, contains one-half mol­ecule, which is completed by a crystallographic center of symmetry. The piperazine ring adopts a chair conformation. In the crystal, weak C—H⋯O inter­actions link the mol­ecules into layers parallel to the bc plane. The crystal packing also exhibits short N⋯N contacts of 3.0467 (16) Å between the terminal diazo N atoms from neighbouring mol­ecules.

Related literature

For related structures in the Cambridge Structural Database (Version 5.34 of November 2012; Allen, 2002[Allen, F. H. (2002). Acta Cryst. B58, 380-388.]), see: Kaupang (2010[Kaupang, Å. (2010). MSc Thesis, University of Oslo, Norway, 230 pp., PDF available online at http://urn.nb.no/URN:NBN:no-26202 or through http://www.duo.uio.no/ .]); Kaupang et al. (2010[Kaupang, Å., Görbitz, C. H. & Hansen, T. (2010). Acta Cryst. E66, o1299.], 2011[Kaupang, Å., Görbitz, C. H. & Hansen, T. (2011). Acta Cryst. E67, o1844-o1845.]); Aliev et al. (1980[Aliev, Z. G., Kartsev, V. G., Atovmyan, L. O. & Bogdanov, G. N. (1980). Khim. Farm. Zh. 14, 84-88.]); Fitzgerald & Jensen (1978[Fitzgerald, A. & Jensen, L. H. (1978). Acta Cryst. B34, 828-836.]); Hope & Black (1972[Hope, H. & Black, K. T. (1972). Acta Cryst. B28, 3632-3634.]). For normal bond lengths in organic compounds, see: Allen et al. (1987[Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1-17.]). For synthetic details, see: Kaupang & Bonge-Hansen (2013[Kaupang, Å. & Bonge-Hansen, T. (2013). Beil. J. Org. Chem. Submitted.]); Kaupang (2010[Kaupang, Å. (2010). MSc Thesis, University of Oslo, Norway, 230 pp., PDF available online at http://urn.nb.no/URN:NBN:no-26202 or through http://www.duo.uio.no/ .]); Toma et al. (2007[Toma, T., Shimokawa, J. & Fukuyama, T. (2007). Org. Lett. 9, 3195-3197.]). For the synthesis of other diazo­acetamides with a 1,4-di­aza six-membered ring, see: Kaupang (2010[Kaupang, Å. (2010). MSc Thesis, University of Oslo, Norway, 230 pp., PDF available online at http://urn.nb.no/URN:NBN:no-26202 or through http://www.duo.uio.no/ .]); Mickelson et al. (1996[Mickelson, J. W., Jacobsen, E. J., Carter, D. B., Im, H. K., Im, W. B., Schreur, P. J. K. D., Sethy, V. H., Tang, A. H., McGee, J. E. & Petke, J. D. (1996). J. Med. Chem. 39, 4654-4666.]). For the synthesis of other diazo­acetamides, see: Ouihia et al. (1993[Ouihia, A., Rene, L., Guilhem, J., Pascard, C. & Badet, B. (1993). J. Org. Chem. 58, 1641-1642.]). For the Chemical Abstracts Service, see: American Chemical Society (2008[American Chemical Society (2008). Chemical Abstracts Service, American Chemical Society, Columbus, OH, USA; accessed Apr 27, 2010.]). For graph-set notation for hydrogen-bonding patterns, see: Etter et al. (1990[Etter, M. C., MacDonald, J. C. & Bernstein, J. (1990). Acta Cryst. B46, 256-262.]).

[Scheme 1]

Experimental

Crystal data
  • C8H10N6O2

  • Mr = 222.22

  • Monoclinic, P 21 /c

  • a = 4.0630 (7) Å

  • b = 9.0941 (15) Å

  • c = 13.230 (2) Å

  • β = 94.453 (2)°

  • V = 487.38 (14) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 0.12 mm−1

  • T = 105 K

  • 1.4 × 0.2 × 0.2 mm

Data collection
  • Bruker APEXII CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2007[Bruker (2007). APEX2, SAINT-Plus and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.859, Tmax = 0.977

  • 4255 measured reflections

  • 1190 independent reflections

  • 1013 reflections with I > 2σ(I)

  • Rint = 0.021

Refinement
  • R[F2 > 2σ(F2)] = 0.034

  • wR(F2) = 0.090

  • S = 1.04

  • 1190 reflections

  • 82 parameters

  • 3 restraints

  • H atoms treated by a mixture of independent and constrained refinement

  • Δρmax = 0.30 e Å−3

  • Δρmin = −0.22 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
C2—H21⋯O1i 0.92 (1) 2.39 (1) 3.2219 (15) 151 (1)
Symmetry code: (i) [-x, y-{\script{1\over 2}}, -z+{\script{1\over 2}}].

Data collection: APEX2 (Bruker, 2007[Bruker (2007). APEX2, SAINT-Plus and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT-Plus (Bruker, 2007[Bruker (2007). APEX2, SAINT-Plus and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Supporting information


Comment top

The N,N'-bis(2-diazoacetyl)piperazine (I) was prepared as part of a series of diazoacetamides (Kaupang et al., 2010; 2011) used in the intramolecular C—H insertion reactions taking place upon thermolysis of their corresponding α-bromodiazoacetamides (Kaupang, 2010). The title compound was synthesized from N,N'-bis(2-bromoacetyl)piperazine following a procedure reported by Toma et al. (2007), modified to employ 1,1,3,3-tetramethylguanidine as the base instead of 1,8-diazabicyclo[5.4.0]undec-7-ene. No previous reports of this compound were found in the Chemical Abstracts Service (CAS; American Chemical Society, 2008).

In (I) (Fig. 1), the piperazine ring is in a normal chair conformation, with one half of the molecule constituting the asymmetric unit. In the Scheme the diazoacetyl group is illustrated in the normal way with CN+ and N+N- double bonds, but sometimes a C—N single bond and a NN triple bond is used. N2—N3 = 1.1239 (14) Å is actually close in length to the triple bond in N2(g) = 1.0976 Å, but N2—C2 = 1.3099 (14) Å is clearly shorter than a normal NN—C(sp3) single bond = 1.493 Å (Allen et al., 1987), illustrating clearly the double bond nature.

As pointed out previously (Kaupang et al., 2010), the ring N atoms have an amide rather than amine character and display an almost planar configuration [sum of C—N1—C angles 358.86 (15)°] due to the double bond character of N1—C1 = 1.3621 (13) Å. There are two interesting intermolecular interactions in the crystal packing (Fig. 2) - a C2—H21···O1 contact (Table 1) giving rise to chains and rings, and a 3.047 (14) Å N3···N3(1 - x,-y,-z) contact between the diazo groups with an associated N2—N3···N3 angle of 115.56 (10)° and N2—N3···N3—N2 torsion angle 180.0°. The diazoacetyl moiety is a relatively rare functional group occurring in 20 different organic molecules in the Cambridge Structural Database (CSD, Version 5.34 of November 2012; Allen 2002), and only three (Aliev et al., 1980; Fitzgerald & Jensen, 1978; Hope & Black, 1972) participate in this type of interaction. Among more general compounds with a diazo group, 40 structures with 53 N···N distance < 3.5 Å were found in the CSD. Most contacts are within the 3.0 to 3.4 Å range. N—N···N angles have a wide distribution, but 45 are in the range 75 - 140° with average value 107°. A trans orientation for the N—N···N—N torsion angle is preferred; 36 out of 53 contacts have values in the range 180 ±20°. Almost all structures with N···N contacts < 3.2 Å fall into this group.

Related literature top

For related structures in the Cambridge Structural Database (Version 5.34 of November 2012; Allen, 2002), see: Kaupang (2010); Kaupang et al. (2010, 2011); Aliev et al. (1980); Fitzgerald & Jensen (1978); Hope & Black (1972). For normal bond lengths in organic compounds, see: Allen et al. (1987). For synthetic details, see: Kaupang & Bonge-Hansen (2013); Kaupang (2010); Toma et al. (2007). For the synthesis of other diazoacetamides with a 1,4-diaza six-membered ring, see: Kaupang (2010); Mickelson et al. (1996). For the synthesis of other diazoacetamides, see: Ouihia et al. (1993). For the Chemical Abstracts Service, see: American Chemical Society (2008). For graph-set notation for hydrogen-bonding patterns, see: Etter et al. (1990).

Experimental top

A solution of 4.0 mg of the title compound in 500 µL of MeCN was placed in a vial measuring 30 × 6 mm and the open vial stored in the dark, exposed to air and at ambient temperature. Slow evaporation afforded yellow needles after 48 h. Crystals are rather fragile and easily fracture if cut with a scalpel. A rather long needle, 1.4 × 0.2 × 0.2 mm, was thus used for data collection.

Refinement top

H atoms bonded to C4 were positioned with idealized geometry and with fixed C—H distances at 0.99 Å, while positional coordinates were refined for H atoms bonded to C2 and C3, as too short intramolecular H···H distances resulted from putting these H atoms in theoretical positions. Distance restraints were imposed on the C2—H21 and C3—H31/H32 bonds utilizing SHELX DFIX 0.95 0.02 and DFIX 0.99 0.02 commands, respectively.

Computing details top

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT-Plus (Bruker, 2007); data reduction: SAINT-Plus (Bruker, 2007); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure of (I) showing the atomic numbering and 50% probability displacement ellipsoids [symmetry code: (') -x, -y, 1 - z].
[Figure 2] Fig. 2. The unit cell and crystal packing of (I) viewed approximately along the a axis with the asymmetric unit covered by a grey ellipse. H atoms not involved in short intermolecular contacts (indicated by dotted lines) have been omitted for clarity. The molecules are connected by C21—H21···O1"(-x, y-1/2-y, 1/2-z) hydrogen bonds into two-dimensional sheets with C(4) chain and R44(26) ring motifs (for graph set notation, see Etter et al., 1990). An intermolecular N3···N3#(1-x,-y,-z) contact has been highlighted in orange.
1,4-Bis(2-diazoacetyl)piperazine top
Crystal data top
C8H10N6O2F(000) = 232
Mr = 222.22Dx = 1.514 Mg m3
Monoclinic, P21/cMelting point: 382 K
Hall symbol: -P 2ybcMo Kα radiation, λ = 0.71073 Å
a = 4.0630 (7) ÅCell parameters from 1727 reflections
b = 9.0941 (15) Åθ = 2.7–28.7°
c = 13.230 (2) ŵ = 0.12 mm1
β = 94.453 (2)°T = 105 K
V = 487.38 (14) Å3Needle, yellow
Z = 21.4 × 0.2 × 0.2 mm
Data collection top
Bruker APEXII CCD
diffractometer
1190 independent reflections
Radiation source: fine-focus sealed tube1013 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.021
Detector resolution: 8.3 pixels mm-1θmax = 28.7°, θmin = 2.7°
Sets of exposures each taken over 0.5° ω rotation scansh = 55
Absorption correction: multi-scan
(SADABS; Bruker, 2007)
k = 1111
Tmin = 0.859, Tmax = 0.977l = 1717
4255 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.034Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.090H atoms treated by a mixture of independent and constrained refinement
S = 1.04 w = 1/[σ2(Fo2) + (0.0478P)2 + 0.1317P]
where P = (Fo2 + 2Fc2)/3
1190 reflections(Δ/σ)max < 0.001
82 parametersΔρmax = 0.30 e Å3
3 restraintsΔρmin = 0.22 e Å3
Crystal data top
C8H10N6O2V = 487.38 (14) Å3
Mr = 222.22Z = 2
Monoclinic, P21/cMo Kα radiation
a = 4.0630 (7) ŵ = 0.12 mm1
b = 9.0941 (15) ÅT = 105 K
c = 13.230 (2) Å1.4 × 0.2 × 0.2 mm
β = 94.453 (2)°
Data collection top
Bruker APEXII CCD
diffractometer
1190 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2007)
1013 reflections with I > 2σ(I)
Tmin = 0.859, Tmax = 0.977Rint = 0.021
4255 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0343 restraints
wR(F2) = 0.090H atoms treated by a mixture of independent and constrained refinement
S = 1.04Δρmax = 0.30 e Å3
1190 reflectionsΔρmin = 0.22 e Å3
82 parameters
Special details top

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 > 2σ(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 (Å2) top
xyzUiso*/Ueq
C10.1936 (3)0.09488 (12)0.31650 (8)0.0164 (2)
C20.2433 (3)0.01250 (13)0.23807 (8)0.0206 (3)
H210.165 (3)0.1064 (14)0.2306 (11)0.025*
C30.0658 (3)0.10152 (12)0.41721 (8)0.0168 (2)
H310.016 (3)0.1708 (14)0.3686 (10)0.020*
H320.308 (3)0.1005 (15)0.4067 (10)0.020*
C40.0370 (3)0.15403 (11)0.47597 (8)0.0169 (2)
H410.27910.16880.46850.020*
H420.07010.24950.46380.020*
N10.0575 (2)0.04673 (10)0.40139 (7)0.0165 (2)
N20.4038 (2)0.03769 (10)0.16317 (7)0.0208 (2)
N30.5432 (3)0.08327 (13)0.10006 (8)0.0295 (3)
O10.2787 (2)0.22436 (9)0.30680 (6)0.0208 (2)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0158 (5)0.0172 (5)0.0158 (5)0.0018 (4)0.0009 (4)0.0016 (4)
C20.0285 (6)0.0176 (5)0.0162 (5)0.0020 (4)0.0047 (4)0.0010 (4)
C30.0204 (5)0.0141 (5)0.0162 (5)0.0021 (4)0.0026 (4)0.0006 (4)
C40.0202 (5)0.0142 (5)0.0167 (5)0.0009 (4)0.0030 (4)0.0012 (4)
N10.0221 (4)0.0131 (4)0.0145 (4)0.0008 (3)0.0035 (3)0.0006 (3)
N20.0264 (5)0.0189 (5)0.0171 (5)0.0024 (4)0.0021 (4)0.0006 (4)
N30.0395 (6)0.0282 (6)0.0222 (5)0.0010 (5)0.0110 (5)0.0007 (4)
O10.0282 (4)0.0154 (4)0.0193 (4)0.0016 (3)0.0047 (3)0.0017 (3)
Geometric parameters (Å, º) top
C1—O11.2367 (14)C3—H310.978 (12)
C1—N11.3621 (13)C3—H320.985 (12)
C1—C21.4504 (16)C4—N11.4602 (13)
C2—N21.3099 (14)C4—H410.9900
C2—H210.915 (12)C4—H420.9900
C3—N11.4589 (13)N2—N31.1239 (14)
C3—C4i1.5193 (15)
O1—C1—N1121.76 (10)H31—C3—H32107.6 (11)
O1—C1—C2120.75 (10)N1—C4—C3i110.54 (9)
N1—C1—C2117.48 (10)N1—C4—H41109.5
N2—C2—C1114.31 (10)C3i—C4—H41109.5
N2—C2—H21115.7 (9)N1—C4—H42109.5
C1—C2—H21129.7 (9)C3i—C4—H42109.5
N1—C3—C4i110.57 (9)H41—C4—H42108.1
N1—C3—H31111.3 (8)C1—N1—C3125.53 (9)
C4i—C3—H31109.1 (8)C1—N1—C4119.16 (9)
N1—C3—H32108.8 (8)C3—N1—C4114.17 (8)
C4i—C3—H32109.5 (8)N3—N2—C2178.58 (12)
O1—C1—C2—N24.86 (16)C2—C1—N1—C4171.95 (9)
N1—C1—C2—N2173.69 (9)C4i—C3—N1—C1137.76 (10)
O1—C1—N1—C3176.58 (10)C4i—C3—N1—C454.61 (12)
C2—C1—N1—C34.88 (15)C3i—C4—N1—C1136.92 (9)
O1—C1—N1—C49.51 (15)C3i—C4—N1—C354.59 (12)
Symmetry code: (i) x, y, z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C2—H21···O1ii0.92 (1)2.39 (1)3.2219 (15)151 (1)
Symmetry code: (ii) x, y1/2, z+1/2.

Experimental details

Crystal data
Chemical formulaC8H10N6O2
Mr222.22
Crystal system, space groupMonoclinic, P21/c
Temperature (K)105
a, b, c (Å)4.0630 (7), 9.0941 (15), 13.230 (2)
β (°) 94.453 (2)
V3)487.38 (14)
Z2
Radiation typeMo Kα
µ (mm1)0.12
Crystal size (mm)1.4 × 0.2 × 0.2
Data collection
DiffractometerBruker APEXII CCD
diffractometer
Absorption correctionMulti-scan
(SADABS; Bruker, 2007)
Tmin, Tmax0.859, 0.977
No. of measured, independent and
observed [I > 2σ(I)] reflections
4255, 1190, 1013
Rint0.021
(sin θ/λ)max1)0.675
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.034, 0.090, 1.04
No. of reflections1190
No. of parameters82
No. of restraints3
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.30, 0.22

Computer programs: APEX2 (Bruker, 2007), SAINT-Plus (Bruker, 2007), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C2—H21···O1i0.915 (12)2.392 (13)3.2219 (15)151.0 (12)
Symmetry code: (i) x, y1/2, z+1/2.
 

References

First citationAliev, Z. G., Kartsev, V. G., Atovmyan, L. O. & Bogdanov, G. N. (1980). Khim. Farm. Zh. 14, 84–88.  CAS
First citationAllen, F. H. (2002). Acta Cryst. B58, 380–388.  Web of Science CrossRef CAS IUCr Journals
First citationAllen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–17.  CrossRef
First citationAmerican Chemical Society (2008). Chemical Abstracts Service, American Chemical Society, Columbus, OH, USA; accessed Apr 27, 2010.
First citationBruker (2007). APEX2, SAINT-Plus and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.
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First citationHope, H. & Black, K. T. (1972). Acta Cryst. B28, 3632–3634.  CSD CrossRef CAS IUCr Journals Web of Science
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First citationKaupang, Å., Görbitz, C. H. & Hansen, T. (2010). Acta Cryst. E66, o1299.  Web of Science CSD CrossRef IUCr Journals
First citationKaupang, Å., Görbitz, C. H. & Hansen, T. (2011). Acta Cryst. E67, o1844–o1845.  Web of Science CSD CrossRef CAS IUCr Journals
First citationMickelson, J. W., Jacobsen, E. J., Carter, D. B., Im, H. K., Im, W. B., Schreur, P. J. K. D., Sethy, V. H., Tang, A. H., McGee, J. E. & Petke, J. D. (1996). J. Med. Chem. 39, 4654–4666.  CrossRef CAS PubMed Web of Science
First citationOuihia, A., Rene, L., Guilhem, J., Pascard, C. & Badet, B. (1993). J. Org. Chem. 58, 1641–1642.  CSD CrossRef CAS Web of Science
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First citationToma, T., Shimokawa, J. & Fukuyama, T. (2007). Org. Lett. 9, 3195–3197.  Web of Science CrossRef PubMed CAS

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