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Two polymorphs of (E,E)-N,N′-bis­(4-nitro­benzyl­idene)benzene-1,4-diamine, C20H14N4O4, (I), have been identified. In each case, the mol­ecule lies across a crystallographic inversion centre. The supra­molecular structure of the first polymorph, (I-1), features stacking based on π–π inter­actions assisted by weak hydrogen bonds involving the nitro groups. The second polymorph, (I-2), displays a perpendicular arrangement of mol­ecules linked via the nitro groups, combined with weak C—H...O hydrogen bonds. Both crystal structures are compared with that of the carbon analogue (E,E)-1,4-bis­[2-(4-nitro­phen­yl)ethen­yl]benzene, (II).

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270111010109/bm3102sup1.cif
Contains datablocks I-1, I-2, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270111010109/bm3102I-1sup2.hkl
Contains datablock I-1

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270111010109/bm3102I-2sup3.hkl
Contains datablock I-2

CCDC references: 829711; 829712

Comment top

Oligomers of poly(p-phenylenevinylene) (PPV) and its isoelectronic counterpart poly(1,4-phenylenemethylidynenitrilo-1,4-phenylenenitrilomethylidyne) (PPI) constitute an interesting class of organic semiconductors, mainly because of the fact that these materials display useful opto-electronic properties. Using oligomers instead of polymers has proved to be a worthwhile endeavour, as the former are far more straightforward to produce, characterize and process than the latter (Müllen & Wegner, 1998). Also, such low-molecular-weight compounds can be subtly tailored to enhance the molecular properties desired for a specific application, by substituting them with functional groups such as electron donors and/or acceptors, thereby making optimal use of their potential as new materials for a variety of applications. However, since these materials are often used in the solid state, it is of equal importance to gain insight into their solid-state structures to correlate their structural characteristics with the experimentally determined opto-electronic properties of interest. In this paper, we present two conformational polymorphs of (E,E)-N,N'-bis(4-nitrobenzylidene)benzene-1,4-diamine, (I), a nitro-substituted PPI oligomer.

The first polymorph, (I-1), crystallizes in the triclinic space group P1 with one molecule per unit cell lying across a crystallographic inversion centre. Its central ring (B) is twisted out of the plane defined by the peripheral nitro-substituted aromatic ring (A) by 56.99 (7)° (Fig. 1); this is further illustrated by the torsion angles presented in Table 1. These twisted conformations are well known within this class of compounds and originate from electronic effects rather than from steric hindrance (Collas et al., 2011). The supramolecular structure of (I-1) is based on extended chains of molecules, generated by a mutual weak hydrogen bond involving the relatively acidic aromatic H5 atom and an O atom from the nitro group in the 4-position (Fig. 2 and Table 2, entry 1). ππ stacks of nitro-substituted rings extend along the direction of the a axis (Fig. 2 and Table 2, entries 2 and 3). Within these stacks, an additional weak hydrogen bond involving H10 of the central ring (C10—H10···O1) operates in the same direction (Fig. 2 and Table 2, entry 4). Finally, a mutual weak hydrogen bond, linking H6 to the π-system of the central ring, holds the stacks together (Fig. 3 and Table 2, entry 5). It is interesting to note that the most acidic H atom, H7, is not involved in the crystal packing.

The second polymorph, (I-2), crystallizes in the monoclinic space group P21/c with two molecules per unit cell lying across crystallographic inversion centres. In its structure one can also easily see that the central ring is twisted out of the plane of the peripheral one (Fig. 1), but to a lesser extent than for (I-1): the angle between the two planes through rings A and B is 36.29 (8)°. As can be seen from Table 1, the torsion angle τ(C11—C9—N2—C7) is the largest contributor to the twists in both structures. The crystal packing of (I-2) is quite different from that of (I-1), as contacts between the nitro groups dominate the supramolecular structure. A `T'-shaped contact between the partially positively charged N atom and the partially negatively charged O atom of the nitro groups results in a herringbone pattern (Fig. 4 and Table 3, entry 1). This type of stacking is reinforced by mutual N—O···π interactions (Fig. 4 and Table 3, entries 2 and 3). Further stacking of the molecules is achieved by two additional weak C—H···O hydrogen bonds involving H6 and H7 (Fig. 5 and Table 3, entries 4 and 5).

The distyrylbenzene (DSB) analogue of the title compounds, namely (E,E)-1,4-bis[2-(4-nitrophenyl)ethenyl]benzene, (II), originally reported by Pham [Pham, 2009; Cambridge Structural Database (CSD; Allen, 2002) refcode MUBTEJ], is quasi-planar with a dihedral angle of 11.86 (7)° between the planes through the peripheral and central rings. The previously reported dimethylformamide (DMF) solvate (Bartholomew et al., 2000; CSD refcode REGBEK) has a dihedral angle of only 2.29 (10)°, but as the solvent molecules interfere in the inter-oligomer contacts, we will only consider the crystal packing of MUBTEJ (Fig. 6). Here, ππ stacking is present but, unlike in the structure of (I-1), it occurs between the two different rings A and B (Table 4, entry 1), which leads to a photoreactive structure that may undergo a topochemical polymerization. Indeed, the distance between the vinyl spacers is 3.95 Å, which is smaller than the experimentally determined limit of 4.2 Å (Schmidt, 1971). Perpendicular to these photoreactive stacks, molecules are connected through three weak hydrogen bonds (Table 4, entries 2, 3 and 4): one in which an aromatic H atom, H5, contacts the π-system of ring A and two in which one of the O atoms of the nitro group, O2, acts as an acceptor for aromatic H atoms H6 and H7.

Thus, the three structures show completely different packing schemes. While in the structure of polymorph (I-1), the central ring B acts as an acceptor for an aromatic H atom, H6, and as a hydrogen-bond donor to a nitro group (C10—H10···O1, Table 2, entry 4), this ring does not take part in the crystal packing of (I-2). Beside the fact that (I-2) and (II) share the same space group, they also share two active sites on their carbon backbone: in both structures, atoms H6 and H7 are engaged in weak hydrogen bonds with the O atoms of the nitro groups. However, in the latter only one O atom is available, while in the former both O atoms are used as acceptor sites. The presence of the N atom in (I), which results in a twist of the central ring, precludes the possibility of closer stacking and, as a result, a photosensitive supramolecular structure based on ππ, as seen in (II), cannot be formed.

Related literature top

For related literature, see: Bartholomew et al. (2000); Collas et al. (2011); Pham (2009); Schmidt (1971).

Experimental top

Benzene-1,2-diamine (2.6 g, 25 mmol) and 4-nitrobenzaldehyde (3.8 g, 50 mmol) were dissolved in ethanol (200 ml) and the resulting solution was boiled under reflux for 2 h. The resulting precipitate was filtered off, yielding a yellow–orange powder, part of which was recrystallized from acetonitrile to produce needles with a golden lustre (I-1). Slow evaporation of a CHCl3 solution yielded polymorph (I-2) as orange plates [m.p. (uncorrected) 512 (I-1) and 502 K (I-2)]. UV/vis (CH2Cl2) λmax = 391 nm (log ε = 4.45). 1H NMR (CDCl3, 400 MHz, TMS): δ 7.36 (s, 4H, H10 and H11), 8.10 (d, 4H, 3J = 8.8 Hz, H2 and H6), 8.35 (d, 3J = 8.8 Hz, H3 and H5), 8.62 (s, 2H, H7). 13C NMR (CDCl3, 100 MHz, TMS): δ 122.20 (C3 and C5), 124.09 (C10 and C11), 129.46 (C2 and C6), 141.53 (C1), 149.76 (C9), 149.76 (C4), 157.03 (C7).

Refinement top

In order to improve R statistics, the high-resolution data were truncated at a resolution of 0.8 Å; this value was chosen based on inspection of the analysis of variance section in the shelx.lst output file. H atoms were placed in calculated positions and refined as riding, with C—H distances of 0.93 Å and Uiso(H) values of 1.2Ueq(C).

Computing details top

For both compounds, data collection: APEX2 (Bruker, 2008); cell refinement: APEX2 (Bruker, 2008); data reduction: APEX2 (Bruker, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and Mercury (Macrae et al., 2008); software used to prepare material for publication: WinGX (Farrugia, 1999) and PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. The molecular structures of (I), showing the atom-numbering scheme [note that in (II), C8 replaces N2]. Displacement ellipsoids are drawn at the 50% probability level; H atoms are represented by spheres with an arbitrary radius and they bear the same number as the C atom to which they are attached.
[Figure 2] Fig. 2. ππ stacking and hydrogen bonding in polymorph (I-1). [Symmetry codes: (i) -x+1, -y, -z+1; (ii) -x+1, -y+1, -z+1; (iii) -x, -y+1, -z+1.]
[Figure 3] Fig. 3. C—H···π contacts in polymorph (I-1). [Symmetry code: (iv) x, -1+y, z.]
[Figure 4] Fig. 4. Interactions involving the nitro group generate a herringbone pattern in polymorph (I-2). [Symmetry codes: (i) -x-1, y+1/2, -z+1/2; (ii) x, y+1, z.]
[Figure 5] Fig. 5. Weak hydrogen bonds in polymorph (I-2). [Symmetry codes: (iii) -x, y-1/2, -z+1/2; (iv) x+1, -1+y, z.]
[Figure 6] Fig. 6. Relevant interactions in MUBTEJ. [Symmetry codes: (ii) x, -y+1/2, z-1/2; (iii) -x+1, y-1/2, -z+1/2.]
(I-1) (E,E)-N,N'-bis(4-nitrobenzylidene)benzene- 1,4-diamine top
Crystal data top
C20H14N4O4Z = 1
Mr = 374.35F(000) = 194
Triclinic, P1Dx = 1.455 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 6.9357 (7) ÅCell parameters from 1698 reflections
b = 7.3036 (7) Åθ = 2.4–31.6°
c = 8.8768 (8) ŵ = 0.11 mm1
α = 73.295 (1)°T = 173 K
β = 82.707 (1)°Plate, orange
γ = 88.071 (1)°0.29 × 0.22 × 0.1 mm
V = 427.20 (7) Å3
Data collection top
Bruker SMART APEX CCD
diffractometer
1731 independent reflections
Radiation source: fine-focus sealed tube1496 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.018
ω scansθmax = 26.4°, θmin = 2.4°
Absorption correction: multi-scan
(APEX2; Bruker, 2008)
h = 88
Tmin = 0.973, Tmax = 0.991k = 99
3748 measured reflectionsl = 1111
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)] = 0.042Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.106H-atom parameters constrained
S = 1.08 w = 1/[σ2(Fo2) + (0.0427P)2 + 0.1688P]
where P = (Fo2 + 2Fc2)/3
1731 reflections(Δ/σ)max < 0.001
127 parametersΔρmax = 0.20 e Å3
0 restraintsΔρmin = 0.22 e Å3
Crystal data top
C20H14N4O4γ = 88.071 (1)°
Mr = 374.35V = 427.20 (7) Å3
Triclinic, P1Z = 1
a = 6.9357 (7) ÅMo Kα radiation
b = 7.3036 (7) ŵ = 0.11 mm1
c = 8.8768 (8) ÅT = 173 K
α = 73.295 (1)°0.29 × 0.22 × 0.1 mm
β = 82.707 (1)°
Data collection top
Bruker SMART APEX CCD
diffractometer
1731 independent reflections
Absorption correction: multi-scan
(APEX2; Bruker, 2008)
1496 reflections with I > 2σ(I)
Tmin = 0.973, Tmax = 0.991Rint = 0.018
3748 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0420 restraints
wR(F2) = 0.106H-atom parameters constrained
S = 1.08Δρmax = 0.20 e Å3
1731 reflectionsΔρmin = 0.22 e Å3
127 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 > 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. The high resolution data was truncated at a resolution of 0.8.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
C10.1930 (2)0.5579 (2)0.66288 (18)0.0178 (3)
C20.1905 (2)0.6598 (2)0.50347 (18)0.0194 (3)
H20.15180.78710.47630.023*
C30.2451 (2)0.5719 (2)0.38690 (18)0.0197 (3)
H30.24480.63880.28060.024*
C40.3006 (2)0.3814 (2)0.43101 (18)0.0189 (3)
C50.3016 (2)0.2756 (2)0.58687 (19)0.0203 (3)
H50.33690.14730.61320.024*
C60.2484 (2)0.3660 (2)0.70286 (19)0.0205 (3)
H60.24950.29810.80890.025*
C70.1418 (2)0.6508 (2)0.78899 (18)0.0192 (3)
H70.16840.58850.89130.023*
C90.0322 (2)0.9033 (2)0.88437 (17)0.0193 (3)
C100.1413 (2)1.0007 (2)0.90212 (18)0.0199 (3)
H100.23561.00230.83600.024*
C110.1744 (2)0.9046 (2)0.98217 (18)0.0201 (3)
H110.29160.84180.96970.024*
N10.36618 (18)0.29163 (19)0.30492 (16)0.0215 (3)
N20.06211 (18)0.81443 (18)0.76120 (15)0.0202 (3)
O10.41396 (17)0.12242 (16)0.34468 (15)0.0295 (3)
O20.37407 (18)0.38908 (17)0.16651 (13)0.0303 (3)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0133 (7)0.0190 (8)0.0217 (8)0.0004 (6)0.0007 (6)0.0076 (6)
C20.0190 (8)0.0160 (7)0.0230 (8)0.0008 (6)0.0016 (6)0.0059 (6)
C30.0194 (8)0.0198 (8)0.0191 (8)0.0003 (6)0.0014 (6)0.0047 (6)
C40.0154 (7)0.0213 (8)0.0234 (8)0.0002 (6)0.0020 (6)0.0119 (6)
C50.0183 (7)0.0169 (7)0.0268 (8)0.0031 (6)0.0043 (6)0.0075 (6)
C60.0194 (8)0.0211 (8)0.0205 (8)0.0013 (6)0.0036 (6)0.0050 (6)
C70.0195 (8)0.0199 (8)0.0176 (7)0.0011 (6)0.0016 (6)0.0046 (6)
C90.0254 (8)0.0152 (7)0.0164 (7)0.0003 (6)0.0007 (6)0.0038 (6)
C100.0250 (8)0.0176 (7)0.0170 (7)0.0019 (6)0.0054 (6)0.0040 (6)
C110.0226 (8)0.0164 (7)0.0205 (8)0.0038 (6)0.0022 (6)0.0048 (6)
N10.0182 (7)0.0245 (7)0.0254 (7)0.0005 (5)0.0031 (5)0.0128 (6)
N20.0215 (7)0.0194 (7)0.0206 (7)0.0010 (5)0.0013 (5)0.0079 (5)
O10.0340 (7)0.0258 (6)0.0354 (7)0.0132 (5)0.0115 (5)0.0179 (5)
O20.0398 (7)0.0303 (7)0.0214 (6)0.0020 (5)0.0023 (5)0.0105 (5)
Geometric parameters (Å, º) top
C1—C61.397 (2)C7—N21.2711 (19)
C1—C21.399 (2)C7—H70.9300
C1—C71.469 (2)C9—C101.392 (2)
C2—C31.376 (2)C9—C111.396 (2)
C2—H20.9300C9—N21.415 (2)
C3—C41.388 (2)C10—C11i1.387 (2)
C3—H30.9300C10—H100.9300
C4—C51.378 (2)C11—C10i1.387 (2)
C4—N11.4704 (19)C11—H110.9300
C5—C61.382 (2)N1—O21.2256 (17)
C5—H50.9300N1—O11.2300 (17)
C6—H60.9300
C6—C1—C2119.62 (14)C1—C6—H6119.6
C6—C1—C7119.41 (14)N2—C7—C1121.39 (14)
C2—C1—C7120.96 (13)N2—C7—H7119.3
C3—C2—C1120.05 (14)C1—C7—H7119.3
C3—C2—H2120.0C10—C9—C11119.42 (14)
C1—C2—H2120.0C10—C9—N2118.31 (14)
C2—C3—C4118.73 (14)C11—C9—N2122.18 (14)
C2—C3—H3120.6C11i—C10—C9120.37 (15)
C4—C3—H3120.6C11i—C10—H10119.8
C5—C4—C3122.83 (14)C9—C10—H10119.8
C5—C4—N1119.05 (13)C10i—C11—C9120.20 (14)
C3—C4—N1118.10 (14)C10i—C11—H11119.9
C4—C5—C6117.90 (14)C9—C11—H11119.9
C4—C5—H5121.0O2—N1—O1123.41 (13)
C6—C5—H5121.0O2—N1—C4118.76 (13)
C5—C6—C1120.85 (14)O1—N1—C4117.82 (13)
C5—C6—H6119.6C7—N2—C9118.55 (13)
C6—C1—C2—C31.0 (2)C11—C9—C10—C11i1.2 (2)
C7—C1—C2—C3177.85 (14)N2—C9—C10—C11i177.87 (13)
C1—C2—C3—C40.5 (2)C10—C9—C11—C10i1.2 (2)
C2—C3—C4—C50.7 (2)N2—C9—C11—C10i177.73 (14)
C2—C3—C4—N1177.55 (13)C5—C4—N1—O2176.47 (14)
C3—C4—C5—C61.4 (2)C3—C4—N1—O21.9 (2)
N1—C4—C5—C6176.88 (13)C5—C4—N1—O12.2 (2)
C4—C5—C6—C10.8 (2)C3—C4—N1—O1179.51 (13)
C2—C1—C6—C50.3 (2)C1—C7—N2—C9174.49 (13)
C7—C1—C6—C5178.54 (14)C10—C9—N2—C7139.76 (15)
C6—C1—C7—N2168.84 (14)C11—C9—N2—C743.7 (2)
C2—C1—C7—N212.3 (2)
Symmetry code: (i) x, y+2, z+2.
(I-2) (E,E)-N,N'-bis(4-nitrobenzylidene)benzene- 1,4-diamine top
Crystal data top
C20H14N4O4F(000) = 388
Mr = 374.35Dx = 1.445 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 1008 reflections
a = 6.567 (1) Åθ = 3.2–23.5°
b = 5.0227 (7) ŵ = 0.10 mm1
c = 26.723 (5) ÅT = 293 K
β = 102.558 (4)°Plate, orange
V = 860.4 (2) Å30.55 × 0.37 × 0.07 mm
Z = 2
Data collection top
Bruker SMART APEX CCD
diffractometer
1753 independent reflections
Radiation source: fine-focus sealed tube1181 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.026
ω scansθmax = 26.4°, θmin = 1.6°
Absorption correction: multi-scan
(APEX2; Bruker, 2008)
h = 87
Tmin = 0.955, Tmax = 0.993k = 66
4451 measured reflectionsl = 3133
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)] = 0.040Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.106H-atom parameters constrained
S = 1.02 w = 1/[σ2(Fo2) + (0.0467P)2 + 0.092P]
where P = (Fo2 + 2Fc2)/3
1753 reflections(Δ/σ)max < 0.001
127 parametersΔρmax = 0.12 e Å3
0 restraintsΔρmin = 0.18 e Å3
Crystal data top
C20H14N4O4V = 860.4 (2) Å3
Mr = 374.35Z = 2
Monoclinic, P21/cMo Kα radiation
a = 6.567 (1) ŵ = 0.10 mm1
b = 5.0227 (7) ÅT = 293 K
c = 26.723 (5) Å0.55 × 0.37 × 0.07 mm
β = 102.558 (4)°
Data collection top
Bruker SMART APEX CCD
diffractometer
1753 independent reflections
Absorption correction: multi-scan
(APEX2; Bruker, 2008)
1181 reflections with I > 2σ(I)
Tmin = 0.955, Tmax = 0.993Rint = 0.026
4451 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0400 restraints
wR(F2) = 0.106H-atom parameters constrained
S = 1.02Δρmax = 0.12 e Å3
1753 reflectionsΔρmin = 0.18 e Å3
127 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 > 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
C10.0372 (2)1.1170 (3)0.37643 (6)0.0435 (4)
C20.1386 (2)1.1873 (4)0.39398 (7)0.0508 (4)
H20.16451.10650.42330.061*
C30.2753 (3)1.3746 (4)0.36876 (6)0.0501 (5)
H30.39421.42000.38050.060*
C40.2331 (2)1.4942 (3)0.32576 (6)0.0424 (4)
C50.0603 (3)1.4307 (4)0.30734 (6)0.0528 (5)
H50.03431.51420.27830.063*
C60.0740 (3)1.2408 (4)0.33280 (6)0.0529 (5)
H60.19151.19440.32060.063*
C70.1888 (3)0.9248 (3)0.40361 (6)0.0485 (4)
H70.30380.88360.39000.058*
C90.3384 (2)0.6540 (3)0.47115 (6)0.0403 (4)
C100.2953 (2)0.4366 (3)0.49885 (6)0.0467 (4)
H100.15740.39300.49850.056*
C110.5467 (2)0.7157 (3)0.47324 (6)0.0470 (4)
H110.57940.86280.45540.056*
N10.3757 (2)1.7008 (3)0.29970 (5)0.0503 (4)
N20.17115 (19)0.8119 (3)0.44468 (5)0.0455 (4)
O10.3319 (2)1.8127 (3)0.26298 (5)0.0696 (4)
O20.5305 (2)1.7529 (3)0.31623 (5)0.0688 (4)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0441 (9)0.0464 (10)0.0393 (8)0.0038 (8)0.0080 (7)0.0024 (8)
C20.0479 (10)0.0577 (11)0.0498 (10)0.0031 (9)0.0176 (8)0.0108 (9)
C30.0446 (9)0.0559 (11)0.0525 (10)0.0050 (8)0.0166 (8)0.0030 (9)
C40.0455 (9)0.0420 (9)0.0375 (8)0.0028 (8)0.0045 (7)0.0018 (8)
C50.0585 (11)0.0627 (12)0.0399 (9)0.0081 (9)0.0166 (8)0.0062 (9)
C60.0502 (10)0.0677 (12)0.0442 (9)0.0149 (9)0.0180 (7)0.0037 (9)
C70.0474 (9)0.0548 (11)0.0439 (9)0.0076 (8)0.0112 (7)0.0027 (9)
C90.0400 (8)0.0414 (9)0.0402 (8)0.0049 (7)0.0101 (7)0.0019 (8)
C100.0374 (8)0.0488 (10)0.0556 (10)0.0002 (8)0.0141 (7)0.0030 (9)
C110.0454 (9)0.0453 (10)0.0522 (10)0.0005 (8)0.0145 (7)0.0093 (8)
N10.0562 (9)0.0478 (9)0.0452 (8)0.0068 (7)0.0071 (7)0.0044 (7)
N20.0419 (7)0.0451 (8)0.0487 (8)0.0037 (6)0.0083 (6)0.0025 (7)
O10.0782 (9)0.0681 (9)0.0631 (8)0.0133 (8)0.0170 (7)0.0207 (8)
O20.0664 (8)0.0756 (10)0.0667 (8)0.0288 (7)0.0195 (7)0.0009 (7)
Geometric parameters (Å, º) top
C1—C21.383 (2)C7—N21.263 (2)
C1—C61.388 (2)C7—H70.9300
C1—C71.461 (2)C9—C101.383 (2)
C2—C31.372 (2)C9—C111.392 (2)
C2—H20.9300C9—N21.414 (2)
C3—C41.377 (2)C10—C11i1.371 (2)
C3—H30.9300C10—H100.9300
C4—C51.369 (2)C11—C10i1.371 (2)
C4—N11.469 (2)C11—H110.9300
C5—C61.375 (2)N1—O11.2186 (18)
C5—H50.9300N1—O21.2215 (18)
C6—H60.9300
C2—C1—C6118.76 (15)C1—C6—H6119.5
C2—C1—C7121.91 (15)N2—C7—C1123.17 (15)
C6—C1—C7119.28 (15)N2—C7—H7118.4
C3—C2—C1120.93 (16)C1—C7—H7118.4
C3—C2—H2119.5C10—C9—C11117.92 (15)
C1—C2—H2119.5C10—C9—N2118.92 (14)
C2—C3—C4118.66 (16)C11—C9—N2123.05 (15)
C2—C3—H3120.7C11i—C10—C9120.84 (15)
C4—C3—H3120.7C11i—C10—H10119.6
C5—C4—C3122.12 (16)C9—C10—H10119.6
C5—C4—N1119.16 (15)C10i—C11—C9121.24 (15)
C3—C4—N1118.70 (15)C10i—C11—H11119.4
C4—C5—C6118.44 (16)C9—C11—H11119.4
C4—C5—H5120.8O1—N1—O2123.61 (15)
C6—C5—H5120.8O1—N1—C4118.02 (14)
C5—C6—C1121.08 (16)O2—N1—C4118.37 (15)
C5—C6—H6119.5C7—N2—C9118.59 (14)
C6—C1—C2—C30.4 (3)C11—C9—C10—C11i1.1 (3)
C7—C1—C2—C3177.88 (16)N2—C9—C10—C11i177.37 (15)
C1—C2—C3—C40.7 (3)C10—C9—C11—C10i1.1 (3)
C2—C3—C4—C50.4 (3)N2—C9—C11—C10i177.21 (15)
C2—C3—C4—N1178.05 (14)C5—C4—N1—O11.5 (2)
C3—C4—C5—C60.2 (3)C3—C4—N1—O1177.00 (15)
N1—C4—C5—C6178.67 (15)C5—C4—N1—O2179.13 (16)
C4—C5—C6—C10.6 (3)C3—C4—N1—O22.4 (2)
C2—C1—C6—C50.3 (3)C1—C7—N2—C9172.48 (15)
C7—C1—C6—C5177.30 (16)C10—C9—N2—C7148.67 (16)
C2—C1—C7—N20.5 (3)C11—C9—N2—C735.2 (2)
C6—C1—C7—N2177.02 (16)
Symmetry code: (i) x+1, y+1, z+1.

Experimental details

(I-1)(I-2)
Crystal data
Chemical formulaC20H14N4O4C20H14N4O4
Mr374.35374.35
Crystal system, space groupTriclinic, P1Monoclinic, P21/c
Temperature (K)173293
a, b, c (Å)6.9357 (7), 7.3036 (7), 8.8768 (8)6.567 (1), 5.0227 (7), 26.723 (5)
α, β, γ (°)73.295 (1), 82.707 (1), 88.071 (1)90, 102.558 (4), 90
V3)427.20 (7)860.4 (2)
Z12
Radiation typeMo KαMo Kα
µ (mm1)0.110.10
Crystal size (mm)0.29 × 0.22 × 0.10.55 × 0.37 × 0.07
Data collection
DiffractometerBruker SMART APEX CCD
diffractometer
Bruker SMART APEX CCD
diffractometer
Absorption correctionMulti-scan
(APEX2; Bruker, 2008)
Multi-scan
(APEX2; Bruker, 2008)
Tmin, Tmax0.973, 0.9910.955, 0.993
No. of measured, independent and
observed [I > 2σ(I)] reflections
3748, 1731, 1496 4451, 1753, 1181
Rint0.0180.026
(sin θ/λ)max1)0.6250.625
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.042, 0.106, 1.08 0.040, 0.106, 1.02
No. of reflections17311753
No. of parameters127127
H-atom treatmentH-atom parameters constrainedH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.20, 0.220.12, 0.18

Computer programs: APEX2 (Bruker, 2008), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997) and Mercury (Macrae et al., 2008), WinGX (Farrugia, 1999) and PLATON (Spek, 2009).

Table 1. Dihedral angles (°) in the compounds under discussion. top
Polymorph (I-1)Polymorph (I-2)MUBTEJREGBEK
C2—C1—C7—N2/C812.3 (2)-0.5 (3)9.5 (2)-5.1 (4)
C1—C7—N2/C8—C9-174.49 (13)-172.48 (15)179.9 (1)-178.4 (2)
C11—C9—N2/C8—C743.7 (2)35.2 (2)-177.6 (1)-175.8 (2)
Table 2. List of short contacts in the crystal packing of polymorph (I-1) (Å, °). The angle related to a pair of centroids is defined as the angle between the Cg(I)···Cg(J) vector and the normal to plane I. Symmetry codes: (i) -x+1, -y, -z+1; (ii) -x+1, -y+1, -z+1; (iii) -x, -y+1, -z+1; (iv) x, y-1, z. top
EntryDXADistanceAngle
1C5H5O1i2.55153
2Cg(A)Cg(A)ii3.5212 (9)15.64
3Cg(A)Cg(A)iii3.5981 (9)24.53
4C10H10O1ii2.52155
5C6H6Cg(B)iv2.83129
Table 3. List of short contacts in the crystal packing of polymorph (I-2) (Å, °). Symmetry codes: (i) -x-1, y+1/2, -z+1/2; (ii) x, y+1, z; (iii) -x, y-1/2, -z+1/2; (iv) x+1, y-1, z. top
EntryDXADistanceAngle
1N1O1N1i2.982 (2)121.20 (11)
2N1O1Cg(A)ii3.5301 (17)86.14 (10)
3N1O2Cg(A)ii3.9359 (18)67.91 (9)
4C6H6O1iii2.66135
5C7H7O2iv2.54152
Table 4. List of short contacts in the crystal packing of (II) (Å, °). The angle related to a pair of centroids is defined as the angle between the Cg(I)···Cg(J) vector and the normal to plane I. Symmetry codes: (i) x-1, y, z-1; (ii) x, -y+1/2, z-1/2; (iii) -x+1, y-1/2, -z+1/2. top
EntryDXADistanceAngle
1Cg(A)Cg(B)i3.8933 (11)29.52
2C5H5Cg(A)ii2.764 (15)160.2 (13)
3C6H6O1iii2.659 (15)146.0 (11)
4C7H7O1iii2.419 (15)161.8 (12)
 

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