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Acta Crystallogr Sect E Struct Rep Online. 2009 August 1; 65(Pt 8): o1833.
Published online 2009 July 11. doi:  10.1107/S1600536809026348
PMCID: PMC2977404

4-Hydrazinopyridinium chloride


In the title compound, C5H8N3 +·Cl, the cation and the anion lie on a mirror plane and are hydrogen bonded in a three-dimensional network via the H atoms of the two hydrazine N atoms. The pyridine N atom is protonated and hydrogen bonded to the terminal hydrazine N atom.

Related literature

For related structures, see: Lima et al. (2008 [triangle]); Hammerl et al. (2001 [triangle]). For background to the synthesis, see: Mann et al. (1959 [triangle]).

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Object name is e-65-o1833-scheme1.jpg


Crystal data

  • C5H8N3 +·Cl
  • M r = 145.59
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-65-o1833-efi1.jpg
  • a = 6.9526 (11) Å
  • b = 6.434 (1) Å
  • c = 7.7432 (12) Å
  • β = 95.316 (1)°
  • V = 344.89 (9) Å3
  • Z = 2
  • Mo Kα radiation
  • μ = 0.46 mm−1
  • T = 173 K
  • 0.27 × 0.19 × 0.18 mm

Data collection

  • Bruker APEXII CCD area-detector diffractometer
  • Absorption correction: multi-scan (SADABS; Bruker, 2006 [triangle]) T min = 0.884, T max = 0.920
  • 4968 measured reflections
  • 855 independent reflections
  • 840 reflections with I > 2σ(I)
  • R int = 0.016


  • R[F 2 > 2σ(F 2)] = 0.022
  • wR(F 2) = 0.060
  • S = 1.13
  • 855 reflections
  • 63 parameters
  • H atoms treated by a mixture of independent and constrained refinement
  • Δρmax = 0.32 e Å−3
  • Δρmin = −0.20 e Å−3

Data collection: APEX2 (Bruker, 2006 [triangle]); cell refinement: SAINT-Plus (Bruker, 2006 [triangle]); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXD (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXTL (Sheldrick, 2008 [triangle]); molecular graphics: Mercury (Macrae et al., 2006 [triangle]); software used to prepare material for publication: publCIF (Westrip, 2009 [triangle]).

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809026348/pv2178sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809026348/pv2178Isup2.hkl

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


The Natural Sciences and Engineering Research Council of Canada (NSERC) is gratefully acknowledged for a Discovery Grant and the Alberta Ingenuity Fund for a studentship (MRH). The diffractometer was purchased with the help of NSERC and the University of Lethbridge.

supplementary crystallographic information


In the structure of the title compound, (I), (Figure 1.) both ions crystallize on the mirror plane perpendicular to b with a separation of b/2 (3.217 Å). In consequence, the N7, N8 and N7—H atom are coplanar with the aromatic ring, and thus the out-of-plane H atoms on N8 are in a staggered conformation with respect to the N7—H atom. The local conformation of the aryl-hydrazine is similar to that observed in only two known crystal structures, both of phenylhydrazine, namely [(C6H5NHNH2)H]2(N3),(II), Hammerl et al. (2001) and [C6H5NHNH3]Cl, (III), Lima et al. (2008). The former contains both PhNHNH2 and PhNHNH3+ in the lattice. However, in (I) it is the more basic pyridine N1 that is protonated, but which also forms a strong H bond to the terminal hydrazinyl N8 (D···A = 2.8069 (19) Å). This bond is comparable in strength to the linking H bond between PhNHNH2 and PhNHNH3+ in (II). The structures of (II) and (III) are also composed of essentially flat sheets of Aryl—N units, with inter-planar separations of 3.497 and 3.378 Å, respectively.

There are additional H bonds between the N7—H and the N8—H atoms and the chloride anion which, in conjunction with the infinite chains of N1—H to N8 bonds, result in the formation of planar hydrogen-bonded sheets (Figure 2), with N···Cl distances very comparable to those found in (III).

In summary, the structure of (I) has a higher symmetry than (II) and (III) and is tightly packed due to a network of strong H bonds.


4-Chloropyridine (1.1 mmol, 4.20 g) and pure hydrazine hydrate (1.1 mmol, 1.63 g) were added to 10 ml of 1-propanol. After refluxing for 48 h, the mixture was cooled to 273 K and washed with cold 1-propanol. Recrystallization from methanol yielded 3.6 g of the title compound (I) as colorless needles in 65% yield. The compound (I) has a melting point of 516–517 K, which was in agreement with published values (Mann et al. 1959).


Space group determination was ambiguous between P21 and P21/m because of poor E-statistics. However, the structure was successfully solved using the SHELXD procedure (Sheldrick, 2008) and refined in P21/m. The origin of the ambiguous E-statistics became obvious after structure solution, as every atom except for the two N8 hydrogen atoms are found on a crystallographic mirror plane. All H atoms were located in a difference map. N-bound H atoms were freely refined with the constraint Uiso(H) = 1.2Ueq(N). The C-bound H atoms were placed in calculated positions (C—H = 0.95 Å) and refined as riding with Uiso(H) = 1.2Ueq(C).


Fig. 1.
A view of (I) plotted with displacement ellipsoids at 50% probability level.
Fig. 2.
Packing diagram of (I) showing the network of H-bonds.

Crystal data

C5H8N3+·ClF(000) = 152
Mr = 145.59Dx = 1.402 Mg m3
Monoclinic, P21/mMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybCell parameters from 4500 reflections
a = 6.9526 (11) Åθ = 2.6–27.5°
b = 6.434 (1) ŵ = 0.46 mm1
c = 7.7432 (12) ÅT = 173 K
β = 95.316 (1)°Block, colourless
V = 344.89 (9) Å30.27 × 0.19 × 0.18 mm
Z = 2

Data collection

Bruker APEXII CCD area-detector diffractometer855 independent reflections
Radiation source: fine-focus sealed tube840 reflections with I > 2σ(I)
graphiteRint = 0.016
[var phi] and ω scansθmax = 27.5°, θmin = 2.6°
Absorption correction: multi-scan (SADABS; Bruker, 2006)h = −9→9
Tmin = 0.884, Tmax = 0.920k = −8→8
4968 measured reflectionsl = −10→10


Refinement on F2Secondary atom site location: notdet
Least-squares matrix: fullHydrogen site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.022H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.060w = 1/[σ2(Fo2) + (0.0256P)2 + 0.1361P] where P = (Fo2 + 2Fc2)/3
S = 1.13(Δ/σ)max < 0.001
855 reflectionsΔρmax = 0.32 e Å3
63 parametersΔρmin = −0.20 e Å3
0 restraintsExtinction correction: SHELXTL (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: dualExtinction coefficient: 0.038 (6)

Special details

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 > σ(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)

Cl10.83751 (5)0.25000.59397 (4)0.02334 (14)
N10.3602 (2)0.2500−0.14229 (17)0.0266 (3)
N70.42703 (18)0.25000.38856 (16)0.0210 (3)
N80.27431 (18)0.25000.49629 (16)0.0212 (3)
C20.2020 (3)0.2500−0.0545 (2)0.0274 (3)
C30.2159 (2)0.25000.12280 (19)0.0238 (3)
C40.4010 (2)0.25000.21599 (18)0.0183 (3)
C50.5645 (2)0.25000.11846 (19)0.0213 (3)
C60.5387 (3)0.2500−0.0580 (2)0.0253 (3)
H10.345 (3)0.2500−0.257 (3)0.030*
H70.545 (3)0.25000.443 (3)0.030*
H80.209 (2)0.139 (2)0.4769 (18)0.030*

Atomic displacement parameters (Å2)

Cl10.01569 (19)0.0324 (2)0.0216 (2)0.000−0.00012 (12)0.000
N10.0429 (8)0.0248 (7)0.0120 (6)0.0000.0026 (5)0.000
N70.0150 (6)0.0346 (7)0.0133 (5)0.0000.0005 (4)0.000
N80.0191 (6)0.0297 (7)0.0151 (6)0.0000.0041 (5)0.000
C20.0305 (8)0.0311 (8)0.0191 (7)0.000−0.0058 (6)0.000
C30.0201 (7)0.0335 (8)0.0174 (7)0.000−0.0003 (5)0.000
C40.0197 (7)0.0202 (7)0.0150 (6)0.0000.0012 (5)0.000
C50.0206 (7)0.0228 (7)0.0209 (7)0.0000.0044 (5)0.000
C60.0345 (8)0.0216 (7)0.0215 (7)0.0000.0114 (6)0.000

Geometric parameters (Å, °)

N1—C21.345 (2)C2—H20.9500
N1—C61.348 (2)C3—C41.416 (2)
N1—H10.89 (2)C3—H30.9500
N7—C41.3317 (18)C4—C51.422 (2)
N7—N81.4097 (17)C5—C61.361 (2)
N7—H70.89 (2)C5—H50.9500
N8—H80.849 (14)C6—H60.9500
C2—C31.368 (2)
C2—N1—C6120.97 (13)C2—C3—H3120.4
C2—N1—H1118.7 (13)C4—C3—H3120.4
C6—N1—H1120.3 (13)N7—C4—C3122.96 (14)
C4—N7—N8123.64 (12)N7—C4—C5119.47 (13)
C4—N7—H7120.4 (13)C3—C4—C5117.58 (13)
N8—N7—H7115.9 (13)C6—C5—C4119.71 (15)
N7—N8—H8108.3 (10)C6—C5—H5120.1
N1—C2—C3121.48 (15)C4—C5—H5120.1
N1—C2—H2119.3N1—C6—C5121.05 (15)
C2—C3—C4119.21 (15)C5—C6—H6119.5

Hydrogen-bond geometry (Å, °)

N7—H7···Cl10.89 (2)2.25 (2)3.1358 (14)177 (2)
N8—H8···Cl1i0.849 (14)2.905 (14)3.1970 (14)102.4 (11)
N1—H1···N8ii0.89 (2)1.92 (2)2.8069 (19)172 (2)

Symmetry codes: (i) x−1, y, z; (ii) x, y, z−1.


Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: PV2178).


  • Bruker (2006). APEX2, SAINT-Plus and SADABS Bruker AXS Inc., Madison, Wisconsin, USA.
  • Hammerl, A., Holl, G., Kaiser, M., Klapotke, T. M., Mayer, P., Nöth, H. & Warchhold, M. (2001). Z. Anorg. Allg. Chem.627, 1477–1482.
  • Lima, G. M. de, Wardell, J. L. & Harrison, W. T. A. (2008). Acta Cryst. E64, o330. [PMC free article] [PubMed]
  • Macrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor, R., Towler, M. & van de Streek, J. (2006). J. Appl. Cryst.39, 453–457.
  • Mann, F. G., Prior, A. F. & Willcox, T. J. (1959). J. Chem. Soc. pp. 3830–3834.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Westrip, S. J. (2009). publCIF In preparation.

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