supplementary materials


qk2056 scheme

Acta Cryst. (2013). E69, o658    [ doi:10.1107/S1600536813008489 ]

An orthorhombic polymorph of 3,4-diaminobenzonitrile

D. K. Geiger and D. E. Parsons

Abstract top

The title compound, C7H7N3, is an orthorhombic polymorph that crystallizes in the space group Pca21. The previously reported monoclinic form [Geiger & Parsons (2013) Acta Cryst. E69, o452] crystallizes in the space group P21/c (Z = 4). In the crystal, two independent HN-H...N[triple bond]C hydrogen bonds link the molecules into chains along the a-glide plane. Two further independent HN-H...NH2 hydrogen bonds join the chains, forming a three-dimensional network.

Comment top

Single crystals of the title compound were obtained by slow evaporation of an ethanolic solution of commercially available 3,4-diaminobenzonitrile. The monoclinic (Geiger & Parsons, 2013) and the orthorhombic polymorphs were obtained from the same batch of crystals. Interestingly, monoclinic (Stålhandske, 1981) and orthorhombic (Czapik & Gdaniec, 2010) polymorphs of the unsubstituted 1,2-diaminobenzene have also been reported.

Figure 1 shows a perspective view of the title compound with the atom numbering scheme. The non-hydrogen atoms of the molecule are essentially planar with a r.m.s. deviation of 0.0449 Å and a maximum deviation of 0.0915 (13) Å for N1. As shown in Fig. 2, in the monoclinic polymorph (Geiger & Parsons, 2013), the amine groups are oriented on the same side of the benzene ring. In contrast, in the orthorhombic form (Fig. 2), they are directed toward opposite sides of the benzene plane. N1 and N2 are 0.072 (2) and 0.074 (2) Å, respectively, out of the plane. In the monoclinic form, the amine groups are decidedly pyramidal whereas the H—N—H angles are 120 (2)° and 116 (2)° for N1 and N2, respectively, in the orthorhomic polymorph. H1A and H1B are 0.10 (2) and 0.09 (2) Å out of the benzene plane and H2A and H2B are 0.42 (2) and 0.08 (2) Å out of the plane. The nitrile group is linear with C3—C7—N3 = 178.5 (2)°.

A comparison of the H-bonding network in the two polymorphs is shown in Fig. 3. Both polymorphs exhibit N—H···NC hydrogen bonding involving both of the amines, which results in chains of molecules (along the a-glide plane for the orthorhomic form and along [1 0 1] in the monoclinic form). However, in the monoclinic polymorph, the molecules in the chain are coplanar while in the orthorhombic polymorph subsequent molecules in the chain subtend an angle of 82.0°. The chains are linked by a network of HN—H···NH2 hydrogen bonds in both forms. In contrast, in the two known polymorphs of 1,2-diaminobenzene (Stålhandske, 1981; Czapik & Gdaniec, 2010), one of the N—H bonds of each amine group is coplanar with the benzene ring and an intramolecular N—H···N interaction is exhibited. Intermolecular hydrogen bonding results in layers that are joined by additional hydrogen-bonding interactions. No intramolecular hydrogen bonding is observed in either polymorph of the title compound.

Related literature top

For the structure of the monoclinic polymorph of the title compound, see: Geiger & Parsons (2013). For the structures of the two crystalline forms of 1,2-diaminobenzene, see: Czapik & Gdaniec (2010); Stålhandske (1981).

Experimental top

Single crystals of the title compound were obtained by slow evaporation of an ethanolic solution of commercially available 3,4-diaminobenzonitrile.

Refinement top

The H atoms bonded to carbon were refined using a riding model with C—H = 0.95 Å and Uiso = 1.2Ueq(C). The coordinates and isotropic thermal parameters of the amine H atoms were refined freely. A negative (meaningless) Flack parameter and corresponding standard deviation were observed. Inversion of the structure also gave nonsensical results for the Flack parameter and use of TWIN and BASF resulted in a negative x parameter. In the absence of significant anomalous scattering, Friedel pairs were merged (MERG 3) and the absolute structure was assigned arbitrarily. Although merging the Friedel pairs gives a poorer data/parameter ratio, the higher ratio with retention of Friedel opposites is illusory.

Computing details top

Data collection: APEX2 (Bruker, 2010); cell refinement: SAINT (Bruker, 2010); data reduction: SAINT (Bruker, 2010); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XSHELL (Bruker, 2010) and Mercury (Macrae et al., 2008); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures top
[Figure 1] Fig. 1. A view of the title compound showing the atom-labeling scheme. Thermal parameters are drawn at the 50% probability level.
[Figure 2] Fig. 2. A view of the amine stereochemistry exhibited by the two polymorphs of the title compound.
[Figure 3] Fig. 3. A view down [100] of the orthorhombic polymorph (top) and down [101] of the monoclinic polymorph showing the H-bonding network.
3,4-Diaminobenzonitrile top
Crystal data top
C7H7N3Dx = 1.302 Mg m3
Mr = 133.16Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Pca21Cell parameters from 1493 reflections
a = 17.425 (3) Åθ = 3.3–24.9°
b = 4.5225 (8) ŵ = 0.09 mm1
c = 8.6167 (16) ÅT = 200 K
V = 679.0 (2) Å3Pyramidal, colourless
Z = 40.60 × 0.30 × 0.30 mm
F(000) = 280
Data collection top
Bruker SMART X2S CCD
diffractometer
652 independent reflections
Radiation source: fine-focus sealed tube598 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.030
Detector resolution: 8.33 pixels mm-1θmax = 25.1°, θmin = 3.3°
ω scansh = 2012
Absorption correction: multi-scan
(SADABS; Bruker, 2010)
k = 55
Tmin = 0.84, Tmax = 0.98l = 1010
3295 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)] = 0.030Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.081H atoms treated by a mixture of independent and constrained refinement
S = 1.08 w = 1/[σ2(Fo2) + (0.0563P)2 + 0.0095P]
where P = (Fo2 + 2Fc2)/3
652 reflections(Δ/σ)max < 0.001
103 parametersΔρmax = 0.09 e Å3
1 restraintΔρmin = 0.14 e Å3
Crystal data top
C7H7N3V = 679.0 (2) Å3
Mr = 133.16Z = 4
Orthorhombic, Pca21Mo Kα radiation
a = 17.425 (3) ŵ = 0.09 mm1
b = 4.5225 (8) ÅT = 200 K
c = 8.6167 (16) Å0.60 × 0.30 × 0.30 mm
Data collection top
Bruker SMART X2S CCD
diffractometer
652 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2010)
598 reflections with I > 2σ(I)
Tmin = 0.84, Tmax = 0.98Rint = 0.030
3295 measured reflectionsθmax = 25.1°
Refinement top
R[F2 > 2σ(F2)] = 0.030H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.081Δρmax = 0.09 e Å3
S = 1.08Δρmin = 0.14 e Å3
652 reflectionsAbsolute structure: ?
103 parametersFlack parameter: ?
1 restraintRogers parameter: ?
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 > 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) top
xyzUiso*/Ueq
N10.50605 (11)0.0476 (4)0.6680 (3)0.0412 (5)
H1A0.5442 (16)0.085 (5)0.737 (4)0.062*
H1B0.5095 (15)0.112 (6)0.602 (4)0.062*
N20.47588 (10)0.4365 (4)0.9148 (2)0.0373 (4)
H2A0.5230 (17)0.459 (5)0.861 (4)0.056*
H2B0.4617 (15)0.591 (6)0.972 (4)0.056*
N30.14367 (11)0.5278 (5)0.7794 (3)0.0640 (7)
C10.43184 (9)0.1346 (4)0.6990 (2)0.0327 (5)
C20.41581 (10)0.3421 (4)0.8177 (2)0.0317 (5)
C30.34103 (10)0.4346 (4)0.8399 (3)0.0354 (5)
H30.33000.57370.91940.043*
C40.28135 (10)0.3268 (4)0.7471 (2)0.0381 (5)
C50.29684 (10)0.1223 (5)0.6311 (3)0.0409 (5)
H50.25650.04810.56800.049*
C60.37141 (12)0.0272 (4)0.6082 (3)0.0397 (5)
H60.38180.11380.52920.048*
C70.20493 (12)0.4373 (5)0.7670 (3)0.0461 (6)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0276 (8)0.0464 (12)0.0496 (12)0.0045 (7)0.0001 (8)0.0074 (9)
N20.0280 (9)0.0437 (10)0.0402 (10)0.0004 (7)0.0032 (8)0.0026 (9)
N30.0318 (10)0.1012 (17)0.0592 (14)0.0168 (9)0.0022 (10)0.0077 (13)
C10.0264 (9)0.0338 (9)0.0378 (12)0.0003 (7)0.0017 (8)0.0061 (9)
C20.0266 (8)0.0356 (10)0.0329 (11)0.0004 (7)0.0006 (8)0.0070 (8)
C30.0300 (9)0.0424 (11)0.0338 (11)0.0046 (8)0.0028 (9)0.0049 (10)
C40.0265 (9)0.0503 (13)0.0375 (12)0.0044 (8)0.0010 (9)0.0125 (10)
C50.0290 (10)0.0517 (12)0.0418 (13)0.0043 (8)0.0038 (10)0.0077 (11)
C60.0354 (11)0.0431 (11)0.0408 (12)0.0012 (8)0.0004 (10)0.0021 (10)
C70.0323 (11)0.0666 (14)0.0393 (13)0.0045 (9)0.0013 (10)0.0087 (11)
Geometric parameters (Å, º) top
N1—C11.378 (3)C2—C31.382 (3)
N1—H1A0.91 (3)C3—C41.399 (3)
N1—H1B0.92 (3)C3—H30.9500
N2—C21.406 (3)C4—C51.388 (3)
N2—H2A0.95 (3)C4—C71.433 (3)
N2—H2B0.89 (3)C5—C61.383 (3)
N3—C71.148 (3)C5—H50.9500
C1—C61.399 (3)C6—H60.9500
C1—C21.416 (3)
C1—N1—H1A120.5 (19)C2—C3—H3119.5
C1—N1—H1B113.8 (16)C4—C3—H3119.5
H1A—N1—H1B120 (2)C5—C4—C3119.93 (16)
C2—N2—H2A112.7 (19)C5—C4—C7119.96 (18)
C2—N2—H2B111.3 (17)C3—C4—C7120.1 (2)
H2A—N2—H2B115 (3)C6—C5—C4119.51 (19)
N1—C1—C6120.0 (2)C6—C5—H5120.2
N1—C1—C2120.94 (17)C4—C5—H5120.2
C6—C1—C2119.04 (17)C5—C6—C1121.3 (2)
C3—C2—N2121.9 (2)C5—C6—H6119.3
C3—C2—C1119.10 (17)C1—C6—H6119.3
N2—C2—C1118.95 (17)N3—C7—C4178.4 (3)
C2—C3—C4121.1 (2)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1A···N3i0.91 (3)2.49 (3)3.218 (3)138 (2)
N1—H1B···N2ii0.92 (3)2.20 (3)3.107 (3)170 (3)
N2—H2A···N3i0.95 (3)2.22 (3)3.152 (3)168 (3)
N2—H2B···N1iii0.89 (3)2.41 (3)3.210 (3)149 (2)
Symmetry codes: (i) x+1/2, y+1, z; (ii) x+1, y, z1/2; (iii) x+1, y+1, z+1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1A···N3i0.91 (3)2.49 (3)3.218 (3)138 (2)
N1—H1B···N2ii0.92 (3)2.20 (3)3.107 (3)170 (3)
N2—H2A···N3i0.95 (3)2.22 (3)3.152 (3)168 (3)
N2—H2B···N1iii0.89 (3)2.41 (3)3.210 (3)149 (2)
Symmetry codes: (i) x+1/2, y+1, z; (ii) x+1, y, z1/2; (iii) x+1, y+1, z+1/2.
Acknowledgements top

This work was supported by a Congressionally directed grant from the US Department of Education (grant No. P116Z100020) for the X-ray diffractometer

references
References top

Bruker (2010). APEX2, SAINT, SADABS and XSHELL. Bruker AXS Inc., Madison, Wisconsin, USA.

Czapik, A. & Gdaniec, M. (2010). Acta Cryst. C66, o198–o201.

Geiger, D. K. & Parsons, D. E. (2013). Acta Cryst. E69, o452.

Macrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466–470.

Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.

Stålhandske, C. (1981). Cryst. Struct. Commun. 10, 1081–1086.

Westrip, S. P. (2010). J. Appl. Cryst. 43, 920–925.