organic compounds
N,N′-Bis(pyridin-2-yl)benzene-1,4-diamine–quinoxaline (2/1)
aFaculty of Chemistry, Adam Mickiewicz University, 60-780 Poznań, Poland
*Correspondence e-mail: magdan@amu.edu.pl
The 16H14N4·C8H6N2, consits of one molecule of N,N′-bis(pyridin-2-yl)benzene-1,4-diamine (PDAB) and one half-molecule of quinoxaline (QX) that is located around an inversion centre and disordered over two overlapping positions. The PDAB molecule adopts a non-planar conformation with an E configuration at the two partially double exo C N bonds of the 2-pyridylamine units. In the crystal, these self-complementary units are N—H⋯N hydrogen bonded via a cyclic R22(8) motif, creating tapes of PDAB molecules extending along [010]. Inversion-related tapes are arranged into pairs through π–π stacking interactions between the benzene rings [centroid–centroid distance = 3.818 (1) Å] and the two symmetry-independent pyridine groups [centroid–centroid distance = 3.760 (1) Å]. The QX molecules are enclosed in a cavity formed between six PDAB tapes.
of the title compound, 2CRelated literature
For the structures of polymorphic forms of N,N′-di(pyridin-2-yl)benzene-1,4-diamine and its with phenazine, see: Bensemann et al. (2002); Wicher & Gdaniec (2011); Gdaniec et al. (2005).
Experimental
Crystal data
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Data collection
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Refinement
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Data collection: CrysAlis CCD (Oxford Diffraction, 2002); cell CrysAlis RED (Oxford Diffraction, 2002); data reduction: CrysAlis RED; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and Mercury (Macrae et al., 2006); software used to prepare material for publication: SHELXL97.
Supporting information
https://doi.org/10.1107/S1600536811046356/rz2662sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536811046356/rz2662Isup2.hkl
N,N'-Di(pyridin-2-yl)benzene-1,4-diamine (0.07 g, 0.27 mmol) was dissolved in an excess of the melted quinoxaline. The solution was heated at 331 K and after a few days colourless crystal suitable for X-ray analysis were obtained.
All H atoms were located in difference electron-density maps, however for further
their positions were determined geometrically with N—H and C—H bond lengths of 0.90 Å and 0.95 Å, respectively. All H atoms were refined in the riding-model approximation, with Uiso(H)=1.2Ueq(N,C).N,N'-Di(pyridin-2-yl)benzene-1,4-diamine (PDAB) is a very versatile supramolecular reagent. It has been shown that it can cocrystallize with the aromatic base, phenazine, forming cocrystals with the 1:4 molar ratio (Gdaniec et al., 2005). In this cocrystal the PDAB molecule is centrosymmetric and adopts a nearly planar conformation and a Z,Z form, i.e. the configuration at the partially double exo C≐ N bonds of its two 2-pyridylamine units is Z. The PDAB molecules are hydrogen bonded to phenazine molecules but, most importantly, their π-faces are directed to the edges of the phenazine molecules arranged via π-π stacking interactions into quartets. To check whether a similar packing motif will be observed for a compound containing the pyrazine fragment but a reduced π-system compared to phenazine, an attempt was made to cocrystallize PDAB with quinoxaline (QX). Cocrystallization was successful when PDAB was dissolved in molten QX (m.p. 301 K) and the solution was slowly evaporated at 331 K yielding the title molecular complex with 2:1 PDAB/QX ratio (Fig. 1). In contrast with the PDAB/phenazine cocrystal, in the title complex the PDAB molecule is nonplanar and adopts an E,E form that promotes formation of a cyclic R22(8) motif via N—H···N hydrogen bond between the self-complementary 2-pyridylamine units (Table 1). These cyclic motifs assemble PDAB molecules into tapes extending along [010]. The tapes related by inversion center are arranged into pairs through π-π stacking interactions between the benzene rings [centroid-centroid distance 3.818 (1) Å] and the two symmetry independent pyridine groups [centroid-centroid distance 3.760 (1) Å] (Fig. 2). Similar tape motifs have been observed in two of the three PDAB polymorphs (Bensemann et al., 2002; Wicher & Gdaniec, 2011), however these polymorphic structures were not stabilized by π-π stacking interactions between the tapes.
The QX molecule, that is not hydrogen bonded to PDAB, is enclosed in a centrosymmetric cavity formed between six PDAB tapes (Fig. 3). This leads to a disorder of the non-centrosymmetric QX molecule which in the cavity is located, with equal occupancies, in two alternative overlapping positions. Thus QX molecule in this
simulates the shape of a naphthalene molecule.As there are no specific interactions between QX and PDAB molecules the driving force for the complex formation with PDAB is different in the two cocrystals with the aromatic heterobases containing the pyrazine ring.
For the structures of polymorphic forms of N,N'-di(pyridin-2-yl)benzene-1,4-diamine and its
with phenazine, see: Bensemann et al. (2002); Wicher & Gdaniec (2011); Gdaniec et al. (2005).Data collection: CrysAlis CCD (Oxford Diffraction, 2002); cell
CrysAlis RED (Oxford Diffraction, 2002); data reduction: CrysAlis RED (Oxford Diffraction, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and Mercury (Macrae et al., 2006); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).2C16H14N4·C8H6N2 | F(000) = 688 |
Mr = 654.77 | Dx = 1.365 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yn | Cell parameters from 2533 reflections |
a = 11.8285 (9) Å | θ = 4.1–25.0° |
b = 9.1223 (7) Å | µ = 0.09 mm−1 |
c = 14.7952 (9) Å | T = 130 K |
β = 93.698 (5)° | Prism, colourless |
V = 1593.1 (2) Å3 | 0.50 × 0.30 × 0.25 mm |
Z = 2 |
Kuma KM-4-CCD κ-geometry diffractometer | 2082 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.033 |
Graphite monochromator | θmax = 25.4°, θmin = 4.1° |
ω scans | h = −13→14 |
8116 measured reflections | k = −10→9 |
2897 independent reflections | l = −17→17 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.045 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.121 | H-atom parameters constrained |
S = 0.97 | w = 1/[σ2(Fo2) + (0.0796P)2] where P = (Fo2 + 2Fc2)/3 |
2897 reflections | (Δ/σ)max < 0.001 |
226 parameters | Δρmax = 0.22 e Å−3 |
0 restraints | Δρmin = −0.28 e Å−3 |
2C16H14N4·C8H6N2 | V = 1593.1 (2) Å3 |
Mr = 654.77 | Z = 2 |
Monoclinic, P21/n | Mo Kα radiation |
a = 11.8285 (9) Å | µ = 0.09 mm−1 |
b = 9.1223 (7) Å | T = 130 K |
c = 14.7952 (9) Å | 0.50 × 0.30 × 0.25 mm |
β = 93.698 (5)° |
Kuma KM-4-CCD κ-geometry diffractometer | 2082 reflections with I > 2σ(I) |
8116 measured reflections | Rint = 0.033 |
2897 independent reflections |
R[F2 > 2σ(F2)] = 0.045 | 0 restraints |
wR(F2) = 0.121 | H-atom parameters constrained |
S = 0.97 | Δρmax = 0.22 e Å−3 |
2897 reflections | Δρmin = −0.28 e Å−3 |
226 parameters |
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. |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
N2 | 0.34420 (10) | 0.46004 (13) | 0.12792 (9) | 0.0251 (3) | |
N7 | 0.44563 (11) | 0.24793 (13) | 0.12278 (9) | 0.0291 (3) | |
H7N | 0.5037 | 0.3082 | 0.1126 | 0.035* | |
N14 | 0.55190 (10) | −0.35168 (13) | 0.12548 (9) | 0.0295 (3) | |
H14N | 0.4941 | −0.4122 | 0.1359 | 0.035* | |
N16 | 0.65420 (10) | −0.56243 (13) | 0.11839 (9) | 0.0260 (3) | |
C1 | 0.34338 (12) | 0.31287 (16) | 0.13482 (10) | 0.0232 (4) | |
C3 | 0.24879 (13) | 0.53106 (17) | 0.14294 (10) | 0.0282 (4) | |
H3 | 0.2492 | 0.6349 | 0.1382 | 0.034* | |
C4 | 0.15003 (13) | 0.46477 (18) | 0.16475 (11) | 0.0301 (4) | |
H4 | 0.0841 | 0.5205 | 0.1745 | 0.036* | |
C5 | 0.15028 (13) | 0.31317 (18) | 0.17200 (11) | 0.0292 (4) | |
H5 | 0.0839 | 0.2630 | 0.1876 | 0.035* | |
C6 | 0.24654 (13) | 0.23600 (17) | 0.15651 (10) | 0.0266 (4) | |
H6 | 0.2474 | 0.1321 | 0.1604 | 0.032* | |
C8 | 0.46942 (13) | 0.09666 (16) | 0.12475 (10) | 0.0243 (4) | |
C9 | 0.40085 (12) | −0.00484 (17) | 0.07789 (10) | 0.0264 (4) | |
H9 | 0.3335 | 0.0269 | 0.0452 | 0.032* | |
C10 | 0.42953 (13) | −0.15119 (16) | 0.07830 (10) | 0.0256 (4) | |
H10 | 0.3813 | −0.2195 | 0.0463 | 0.031* | |
C11 | 0.52812 (13) | −0.20032 (16) | 0.12488 (10) | 0.0253 (4) | |
C12 | 0.59638 (13) | −0.09904 (17) | 0.17195 (11) | 0.0272 (4) | |
H12 | 0.6637 | −0.1307 | 0.2047 | 0.033* | |
C13 | 0.56739 (13) | 0.04714 (17) | 0.17172 (10) | 0.0270 (4) | |
H13 | 0.6152 | 0.1152 | 0.2042 | 0.032* | |
C15 | 0.65386 (13) | −0.41581 (16) | 0.11138 (10) | 0.0239 (4) | |
C17 | 0.75049 (13) | −0.63284 (18) | 0.10303 (11) | 0.0302 (4) | |
H17 | 0.7507 | −0.7367 | 0.1074 | 0.036* | |
C18 | 0.84841 (14) | −0.56538 (18) | 0.08156 (11) | 0.0310 (4) | |
H18 | 0.9149 | −0.6201 | 0.0719 | 0.037* | |
C19 | 0.84671 (13) | −0.41393 (18) | 0.07442 (11) | 0.0303 (4) | |
H19 | 0.9129 | −0.3628 | 0.0594 | 0.036* | |
C20 | 0.75006 (13) | −0.33812 (17) | 0.08900 (10) | 0.0276 (4) | |
H20 | 0.7482 | −0.2343 | 0.0840 | 0.033* | |
C21 | 0.42626 (15) | 0.38226 (19) | 0.36086 (12) | 0.0393 (5) | |
H21 | 0.3839 | 0.3310 | 0.3142 | 0.047* | |
C22 | 0.53039 (16) | 0.44592 (18) | 0.34188 (13) | 0.0410 (5) | |
H22 | 0.5570 | 0.4363 | 0.2829 | 0.049* | |
N23 | 0.59282 (13) | 0.51949 (17) | 0.40527 (11) | 0.0368 (4) | 0.50 |
C23 | 0.59282 (13) | 0.51949 (17) | 0.40527 (11) | 0.0368 (4) | 0.50 |
H23 | 0.6629 | 0.5629 | 0.3922 | 0.044* | 0.50 |
C24 | 0.55231 (12) | 0.53158 (16) | 0.49075 (11) | 0.0275 (4) | |
C25 | 0.61465 (13) | 0.60804 (16) | 0.55764 (11) | 0.0357 (4) | 0.50 |
H25 | 0.6846 | 0.6529 | 0.5457 | 0.043* | 0.50 |
N25 | 0.61465 (13) | 0.60804 (16) | 0.55764 (11) | 0.0357 (4) | 0.50 |
U11 | U22 | U33 | U12 | U13 | U23 | |
N2 | 0.0240 (7) | 0.0225 (7) | 0.0290 (7) | 0.0005 (5) | 0.0025 (6) | −0.0026 (5) |
N7 | 0.0227 (7) | 0.0202 (7) | 0.0449 (9) | −0.0022 (5) | 0.0067 (6) | −0.0004 (6) |
N14 | 0.0224 (7) | 0.0208 (7) | 0.0457 (9) | −0.0006 (5) | 0.0056 (6) | 0.0047 (6) |
N16 | 0.0248 (7) | 0.0229 (7) | 0.0301 (8) | 0.0004 (5) | 0.0011 (6) | −0.0004 (6) |
C1 | 0.0249 (8) | 0.0223 (8) | 0.0223 (8) | −0.0012 (6) | 0.0010 (6) | −0.0020 (6) |
C3 | 0.0301 (9) | 0.0246 (8) | 0.0298 (9) | 0.0026 (7) | 0.0012 (7) | −0.0040 (7) |
C4 | 0.0243 (8) | 0.0339 (9) | 0.0323 (9) | 0.0032 (7) | 0.0030 (7) | −0.0048 (7) |
C5 | 0.0247 (8) | 0.0361 (9) | 0.0270 (9) | −0.0044 (7) | 0.0026 (7) | −0.0009 (7) |
C6 | 0.0283 (9) | 0.0239 (8) | 0.0277 (9) | −0.0022 (7) | 0.0019 (7) | 0.0000 (6) |
C8 | 0.0238 (8) | 0.0212 (8) | 0.0284 (9) | −0.0007 (6) | 0.0059 (7) | 0.0001 (6) |
C9 | 0.0241 (8) | 0.0258 (8) | 0.0292 (9) | 0.0000 (7) | 0.0004 (7) | 0.0024 (7) |
C10 | 0.0244 (8) | 0.0253 (8) | 0.0271 (9) | −0.0034 (6) | 0.0010 (6) | −0.0015 (6) |
C11 | 0.0257 (8) | 0.0219 (8) | 0.0289 (9) | 0.0009 (6) | 0.0056 (7) | 0.0024 (6) |
C12 | 0.0231 (8) | 0.0299 (9) | 0.0283 (9) | 0.0019 (7) | 0.0003 (7) | 0.0026 (7) |
C13 | 0.0248 (8) | 0.0277 (9) | 0.0288 (9) | −0.0034 (7) | 0.0034 (7) | −0.0035 (7) |
C15 | 0.0242 (8) | 0.0246 (8) | 0.0225 (8) | 0.0002 (6) | −0.0007 (6) | 0.0002 (6) |
C17 | 0.0298 (9) | 0.0267 (8) | 0.0336 (9) | 0.0037 (7) | −0.0010 (7) | −0.0037 (7) |
C18 | 0.0259 (9) | 0.0337 (9) | 0.0334 (9) | 0.0028 (7) | 0.0011 (7) | −0.0068 (7) |
C19 | 0.0231 (9) | 0.0374 (10) | 0.0302 (9) | −0.0054 (7) | 0.0012 (7) | −0.0031 (7) |
C20 | 0.0273 (9) | 0.0259 (8) | 0.0292 (9) | −0.0028 (7) | −0.0004 (7) | 0.0008 (7) |
C21 | 0.0462 (11) | 0.0331 (10) | 0.0372 (11) | −0.0056 (8) | −0.0086 (9) | 0.0026 (8) |
C22 | 0.0550 (12) | 0.0324 (10) | 0.0362 (10) | 0.0004 (9) | 0.0081 (9) | 0.0027 (8) |
N23 | 0.0364 (9) | 0.0337 (9) | 0.0411 (10) | −0.0045 (7) | 0.0092 (7) | 0.0025 (7) |
C23 | 0.0364 (9) | 0.0337 (9) | 0.0411 (10) | −0.0045 (7) | 0.0092 (7) | 0.0025 (7) |
C24 | 0.0263 (8) | 0.0214 (8) | 0.0344 (9) | 0.0003 (6) | −0.0005 (7) | 0.0021 (7) |
C25 | 0.0314 (8) | 0.0331 (9) | 0.0417 (10) | −0.0057 (7) | −0.0055 (7) | 0.0031 (7) |
N25 | 0.0314 (8) | 0.0331 (9) | 0.0417 (10) | −0.0057 (7) | −0.0055 (7) | 0.0031 (7) |
N2—C3 | 1.3324 (18) | C11—C12 | 1.385 (2) |
N2—C1 | 1.3465 (19) | C12—C13 | 1.377 (2) |
N7—C1 | 1.3686 (19) | C12—H12 | 0.9500 |
N7—C8 | 1.4083 (19) | C13—H13 | 0.9500 |
N7—H7N | 0.9001 | C15—C20 | 1.398 (2) |
N14—C15 | 1.3685 (19) | C17—C18 | 1.367 (2) |
N14—C11 | 1.4090 (19) | C17—H17 | 0.9500 |
N14—H14N | 0.9000 | C18—C19 | 1.386 (2) |
N16—C17 | 1.3397 (19) | C18—H18 | 0.9500 |
N16—C15 | 1.3415 (19) | C19—C20 | 1.365 (2) |
C1—C6 | 1.398 (2) | C19—H19 | 0.9500 |
C3—C4 | 1.372 (2) | C20—H20 | 0.9500 |
C3—H3 | 0.9500 | C21—N25i | 1.331 (2) |
C4—C5 | 1.387 (2) | C21—C25i | 1.331 (2) |
C4—H4 | 0.9500 | C21—C22 | 1.406 (3) |
C5—C6 | 1.370 (2) | C21—H21 | 0.9499 |
C5—H5 | 0.9500 | C22—N23 | 1.336 (2) |
C6—H6 | 0.9500 | C22—H22 | 0.9500 |
C8—C9 | 1.387 (2) | N23—C24 | 1.385 (2) |
C8—C13 | 1.388 (2) | N23—H23 | 0.9500 |
C9—C10 | 1.377 (2) | C24—C25 | 1.384 (2) |
C9—H9 | 0.9500 | C24—C24i | 1.408 (3) |
C10—C11 | 1.390 (2) | C25—C21i | 1.331 (2) |
C10—H10 | 0.9500 | C25—H25 | 0.9499 |
C3—N2—C1 | 117.51 (13) | C11—C12—H12 | 119.7 |
C1—N7—C8 | 126.76 (13) | C12—C13—C8 | 121.08 (14) |
C1—N7—H7N | 116.6 | C12—C13—H13 | 119.5 |
C8—N7—H7N | 116.6 | C8—C13—H13 | 119.5 |
C15—N14—C11 | 126.54 (13) | N16—C15—N14 | 114.37 (13) |
C15—N14—H14N | 116.8 | N16—C15—C20 | 121.68 (14) |
C11—N14—H14N | 116.7 | N14—C15—C20 | 123.92 (14) |
C17—N16—C15 | 117.59 (14) | N16—C17—C18 | 124.47 (15) |
N2—C1—N7 | 114.27 (13) | N16—C17—H17 | 117.8 |
N2—C1—C6 | 121.83 (14) | C18—C17—H17 | 117.8 |
N7—C1—C6 | 123.84 (14) | C17—C18—C19 | 117.27 (15) |
N2—C3—C4 | 124.61 (15) | C17—C18—H18 | 121.4 |
N2—C3—H3 | 117.7 | C19—C18—H18 | 121.4 |
C4—C3—H3 | 117.7 | C20—C19—C18 | 120.08 (15) |
C3—C4—C5 | 117.38 (15) | C20—C19—H19 | 120.0 |
C3—C4—H4 | 121.3 | C18—C19—H19 | 120.0 |
C5—C4—H4 | 121.3 | C19—C20—C15 | 118.89 (15) |
C6—C5—C4 | 119.79 (15) | C19—C20—H20 | 120.6 |
C6—C5—H5 | 120.1 | C15—C20—H20 | 120.6 |
C4—C5—H5 | 120.1 | N25i—C21—C22 | 121.85 (16) |
C5—C6—C1 | 118.86 (15) | C25i—C21—C22 | 121.85 (16) |
C5—C6—H6 | 120.6 | N25i—C21—H21 | 119.1 |
C1—C6—H6 | 120.6 | C25i—C21—H21 | 119.1 |
C9—C8—C13 | 118.40 (14) | C22—C21—H21 | 119.1 |
C9—C8—N7 | 122.29 (14) | N23—C22—C21 | 121.25 (17) |
C13—C8—N7 | 119.25 (13) | N23—C22—H22 | 119.3 |
C10—C9—C8 | 120.60 (14) | C21—C22—H22 | 119.4 |
C10—C9—H9 | 119.7 | C22—N23—C24 | 118.20 (15) |
C8—C9—H9 | 119.7 | C22—N23—H23 | 121.1 |
C9—C10—C11 | 120.88 (14) | C24—N23—H23 | 120.7 |
C9—C10—H10 | 119.6 | C25—C24—N23 | 119.55 (14) |
C11—C10—H10 | 119.6 | C25—C24—C24i | 120.10 (19) |
C12—C11—C10 | 118.52 (14) | N23—C24—C24i | 120.34 (18) |
C12—C11—N14 | 122.74 (14) | C21i—C25—C24 | 118.25 (15) |
C10—C11—N14 | 118.68 (13) | C21i—C25—H25 | 120.8 |
C13—C12—C11 | 120.52 (14) | C24—C25—H25 | 120.9 |
C13—C12—H12 | 119.7 | ||
C3—N2—C1—N7 | −177.03 (13) | C11—C12—C13—C8 | 0.1 (2) |
C3—N2—C1—C6 | 0.3 (2) | C9—C8—C13—C12 | 0.1 (2) |
C8—N7—C1—N2 | −178.90 (14) | N7—C8—C13—C12 | −177.06 (14) |
C8—N7—C1—C6 | 3.9 (2) | C17—N16—C15—N14 | 178.27 (13) |
C1—N2—C3—C4 | −0.1 (2) | C17—N16—C15—C20 | −0.1 (2) |
N2—C3—C4—C5 | 0.3 (2) | C11—N14—C15—N16 | 178.07 (14) |
C3—C4—C5—C6 | −0.7 (2) | C11—N14—C15—C20 | −3.6 (2) |
C4—C5—C6—C1 | 0.9 (2) | C15—N16—C17—C18 | 0.6 (2) |
N2—C1—C6—C5 | −0.7 (2) | N16—C17—C18—C19 | −0.7 (2) |
N7—C1—C6—C5 | 176.37 (14) | C17—C18—C19—C20 | 0.3 (2) |
C1—N7—C8—C9 | 47.3 (2) | C18—C19—C20—C15 | 0.2 (2) |
C1—N7—C8—C13 | −135.63 (16) | N16—C15—C20—C19 | −0.3 (2) |
C13—C8—C9—C10 | 0.1 (2) | N14—C15—C20—C19 | −178.51 (14) |
N7—C8—C9—C10 | 177.18 (14) | N25i—C21—C22—N23 | −0.1 (3) |
C8—C9—C10—C11 | −0.6 (2) | C25i—C21—C22—N23 | −0.1 (3) |
C9—C10—C11—C12 | 0.8 (2) | C21—C22—N23—C24 | 0.0 (3) |
C9—C10—C11—N14 | 178.09 (14) | C22—N23—C24—C25 | −179.52 (15) |
C15—N14—C11—C12 | −48.1 (2) | C22—N23—C24—C24i | −0.4 (3) |
C15—N14—C11—C10 | 134.72 (16) | N23—C24—C25—C21i | −179.92 (15) |
C10—C11—C12—C13 | −0.6 (2) | C24i—C24—C25—C21i | 1.0 (3) |
N14—C11—C12—C13 | −177.76 (14) |
Symmetry code: (i) −x+1, −y+1, −z+1. |
D—H···A | D—H | H···A | D···A | D—H···A |
N14—H14N···N2ii | 0.90 | 2.12 | 2.9998 (17) | 166 |
N7—H7N···N16iii | 0.90 | 2.13 | 3.0173 (18) | 167 |
Symmetry codes: (ii) x, y−1, z; (iii) x, y+1, z. |
Experimental details
Crystal data | |
Chemical formula | 2C16H14N4·C8H6N2 |
Mr | 654.77 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 130 |
a, b, c (Å) | 11.8285 (9), 9.1223 (7), 14.7952 (9) |
β (°) | 93.698 (5) |
V (Å3) | 1593.1 (2) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.09 |
Crystal size (mm) | 0.50 × 0.30 × 0.25 |
Data collection | |
Diffractometer | Kuma KM-4-CCD κ-geometry |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 8116, 2897, 2082 |
Rint | 0.033 |
(sin θ/λ)max (Å−1) | 0.602 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.045, 0.121, 0.97 |
No. of reflections | 2897 |
No. of parameters | 226 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.22, −0.28 |
Computer programs: CrysAlis CCD (Oxford Diffraction, 2002), CrysAlis RED (Oxford Diffraction, 2002), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997) and Mercury (Macrae et al., 2006).
D—H···A | D—H | H···A | D···A | D—H···A |
N14—H14N···N2i | 0.90 | 2.12 | 2.9998 (17) | 166 |
N7—H7N···N16ii | 0.90 | 2.13 | 3.0173 (18) | 167 |
Symmetry codes: (i) x, y−1, z; (ii) x, y+1, z. |
References
Bensemann, I., Gdaniec, M. & Połoński, T. (2002). New J. Chem. 26, 448–456. Web of Science CSD CrossRef CAS Google Scholar
Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565. CrossRef IUCr Journals Google Scholar
Gdaniec, M., Bensemann, I. & Połoński, T. (2005). CrystEngComm, 7, 433–438. Web of Science CSD CrossRef CAS Google Scholar
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. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Oxford Diffraction (2002). CrysAlis CCD and CrysAlis RED. Oxford Diffraction Ltd, Abingdon, England. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Wicher, B. & Gdaniec, M. (2011). Acta Cryst. E67, o3095. Web of Science CSD CrossRef IUCr Journals Google Scholar
This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
N,N'-Di(pyridin-2-yl)benzene-1,4-diamine (PDAB) is a very versatile supramolecular reagent. It has been shown that it can cocrystallize with the aromatic base, phenazine, forming cocrystals with the 1:4 molar ratio (Gdaniec et al., 2005). In this cocrystal the PDAB molecule is centrosymmetric and adopts a nearly planar conformation and a Z,Z form, i.e. the configuration at the partially double exo C≐ N bonds of its two 2-pyridylamine units is Z. The PDAB molecules are hydrogen bonded to phenazine molecules but, most importantly, their π-faces are directed to the edges of the phenazine molecules arranged via π-π stacking interactions into quartets. To check whether a similar packing motif will be observed for a compound containing the pyrazine fragment but a reduced π-system compared to phenazine, an attempt was made to cocrystallize PDAB with quinoxaline (QX). Cocrystallization was successful when PDAB was dissolved in molten QX (m.p. 301 K) and the solution was slowly evaporated at 331 K yielding the title molecular complex with 2:1 PDAB/QX ratio (Fig. 1). In contrast with the PDAB/phenazine cocrystal, in the title complex the PDAB molecule is nonplanar and adopts an E,E form that promotes formation of a cyclic R22(8) motif via N—H···N hydrogen bond between the self-complementary 2-pyridylamine units (Table 1). These cyclic motifs assemble PDAB molecules into tapes extending along [010]. The tapes related by inversion center are arranged into pairs through π-π stacking interactions between the benzene rings [centroid-centroid distance 3.818 (1) Å] and the two symmetry independent pyridine groups [centroid-centroid distance 3.760 (1) Å] (Fig. 2). Similar tape motifs have been observed in two of the three PDAB polymorphs (Bensemann et al., 2002; Wicher & Gdaniec, 2011), however these polymorphic structures were not stabilized by π-π stacking interactions between the tapes.
The QX molecule, that is not hydrogen bonded to PDAB, is enclosed in a centrosymmetric cavity formed between six PDAB tapes (Fig. 3). This leads to a disorder of the non-centrosymmetric QX molecule which in the cavity is located, with equal occupancies, in two alternative overlapping positions. Thus QX molecule in this crystal structure simulates the shape of a naphthalene molecule.
As there are no specific interactions between QX and PDAB molecules the driving force for the complex formation with PDAB is different in the two cocrystals with the aromatic heterobases containing the pyrazine ring.