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Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 71| Part 2| February 2015| Pages 180-183

Crystal structure of 2,2′-oxybis(4-methylquinoline)

aDepartment of Chemistry, University of Namur, 61, Rue de Bruxelles, B-5000 Namur, Belgium
*Correspondence e-mail: anaelle.tilborg@unamur.be

Edited by R. F. Baggio, Comisión Nacional de Energía Atómica, Argentina (Received 15 December 2014; accepted 13 January 2015; online 17 January 2015)

The title compound, C20H16N2O, (I), has been unwittingly obtained from the slow evaporation of a saturated solution of commercial benserazide hydro­chloride [benserazide, (II), being one of the principal therapeutic compounds used for the management of Parkinson's disease, mostly used in combination with levodopa]. The mol­ecule of (I) is composed of two planar 4-methyl­quinoline aromatic moieties [maximum deviations of 0.0104 (18) and 0.016 (2) Å], almost perpendicular to each other [dihedral angle = 89.5 (2)°], bridged by an O atom. The supra­molecular organization consists of a π-bonded chain, resulting from the stacking of mol­ecules related by inversion centres located along direction [111].

1. Chemical context

Parkinson's disease is a degenerative disorder of the central nervous system, resulting from the death of dopamine-generating cells, mostly located in the mid-brain. The most obvious symptoms are movement-related: uncontrolled shaking, rigidity, slowness of movement and difficulty in walking. However, behavioral problems and psychiatric depression may also arise (Samii et al., 2004[Samii, A., Nutt, J. G. & Ransom, B. R. (2004). Lancet, 363, 1783-1793.]). Symptomatic treatment of Parkinson's disease includes daily dopamine administration, principally through L-DOPA (or levodopa) or carbidopa (both being precursors of dopamine) brain metabolization.

[Scheme 1]

Benserazide [also called Serazide or Ro–4–4602, (II) in the Scheme] is an aromatic L-amino acid deca­rboxylase inhibitor and a DOPA deca­rboxylase inhibitor unable to cross the blood–brain barrier. It is used in combination with levodopa for the symptomatic management of Parkinson's disease (Clark et al., 1973[Clark, W. G., Oldendorf, W. H. & Dewhurst, W. G. (1973). J. Pharm. Pharmacol. 25, 416-418.]; Campanella & Pennetta, 1974[Campanella, G. & Pennetta, R. (1974). Acta Neurol. 29, 252-263.]; Bortolanza et al., 2015[Bortolanza, M., Cavalcanti-Kiwiatkoski, R., Padovan-Neto, F. E., Da Silva, C. A., Mitkovski, M., Raisman-Vozari, R. & Del-Bel, E. (2015). Neurobiol. Dis. 73, 377-387.]).

As benserazide is always administered in combination therapy, it appeared to be a good candidate to search for a solid-state crystalline phase involving it with another thera­peutic mol­ecule, also active in the treatment of Parkinson's disease. However, little information could be retrieved on the structural aspects of benserazide and, as a first step, recrystallization attempts of the mol­ecule alone have been launched. These crystallization assays have been so far fruitless, but resulted instead in the unwitting obtention of a new mol­ecule, 2,2′-oxybis(4-methylquinoline) (I)[link] with formula C20H16ON2, which is reported herein.

2. Structural commentary

The geometry of (I)[link] is fairly predictable, with all bond lengths and valence angles being in the expected range for organic compounds (Allen et al., 1987[Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1-19.]). The mol­ecule consists of two planar 4-methyl­quinoline aromatic moieties [the maximum deviations from the mean plane are 0.0104 (18) Å for C1 in the N1,C1–C9 moiety and 0.016 (2) Å for C13 in the N2,C11–C19 unit], almost perpendicular to each other [dihedral angle = 89.5 (2)°] and bound by an oxygen atom which forms an ether link (Fig. 1[link]).

[Figure 1]
Figure 1
The mol­ecular structure and atom numbering of the title compound. Displacement ellipsoids for the non-H atoms are drawn at the 50% probability level.

3. Supra­molecular features

The crystal packing organization is essentially the result of two different types of π-stacking inter­actions involving inversion-related mol­ecules. Table 1[link] gives a survey of these ππ stacking inter­actions, in one case around (½, ½, ½) (Fig. 2[link]) and in the other case around (0, 0, 0);(1, 1, 1) (Fig. 3[link]). The overall effect of these inter­actions is the formation of chains parallel to [111] (Fig. 4[link]). As expected from the lack of efficient hydrogen-bond donors, no significant hydrogen bonds linking the chains are present in the structure, as a result of which their mutual inter­action is rather weak.

Table 1
ππ stacking inter­actions (Å, °)

Cg1, Cg2, Cg3 and Cg4 are the centroids of the N1/C1–C5, N2/C11–C15, C4–C9 and C14–C19 rings, respectively. Cg⋯Cg is the inter­centroid distance, the dihedral angle is between the ring planes and mpd is the mean perpendicular distance between a centroid and the opposite plane.

  CgCg dihedral angle mpd
Cg1⋯Cg1i 3.7849 (11) 0 3.4446 (7)
Cg1⋯Cg3i 3.7775 (11) 0.83 (8) 3.4345 (10)
Cg2⋯Cg2ii 3.6036 (11) 0 3.4395 (7)
Cg2⋯Cg4ii 3.8817 (12) 0.73 (10) 3.4462 (19)
Symmetry codes: (i) −x, −y, −z; (ii) 1 − x, 1 − y, 1 − z.
[Figure 2]
Figure 2
Packing diagram showing one of the ππ inter­actions, stacked around (½, ½, ½).
[Figure 3]
Figure 3
Packing diagram showing the second type of ππ inter­action, stacked around (1, 1, 1).
[Figure 4]
Figure 4
The [111] chain resulting from the two types of ππ inter­actions.

4. Database survey

A systematic research in the Cambridge Structural Database (CSD; Version 5.35, update November 2014; Groom & Allen, 2014[Groom, C. R. & Allen, F. H. (2014). Angew. Chem. Int. Ed. 53, 662-671.]) using ConQuest (Bruno et al., (2002[Bruno, I. J., Cole, J. C., Edgington, P. R., Kessler, M., Macrae, C. F., McCabe, P., Pearson, J. & Taylor, R. (2002). Acta Cryst. B58, 389-397.]) revealed some structures fairly similar to (I)[link], which are presented in Fig. 5[link] and identified by their CSD refcodes: MOSLAI (Hassan et al., 2009[Hassan, N. D., Tajuddin, H. A., Abdullah, Z. & Ng, S. W. (2009). Acta Cryst. E65, o732.]) and JUBRAZ (Liu et al., 1992[Liu, H., Wang, X. & Zhang, X. (1992). Acta Cryst. C48, 2096-2098.]), the main difference residing in the number and relative position of the nitro­gen atoms in the aromatic rings.

[Figure 5]
Figure 5
Two similar structures in the CSD [refcodes MOSLAI (Hassan et al., 2009[Hassan, N. D., Tajuddin, H. A., Abdullah, Z. & Ng, S. W. (2009). Acta Cryst. E65, o732.]) and JUBRAZ (Liu et al., 1992[Liu, H., Wang, X. & Zhang, X. (1992). Acta Cryst. C48, 2096-2098.])].

5. Synthesis and crystallization

Prismatic colourless crystals of 2,2′-oxybis(4-methylquinoline) were grown from a 2 ml aqueous saturated solution of benserazide hydro­chloride (purchased from Sigma-Aldrich, Steinheim, Germany; purity level claimed > 98%) (9.3 mg) that was allowed to evaporate slowly at room temperature over 7 days.

Several trials of slow evaporation of aqueous solutions under different temperature conditions (from 277 to 313 K) provided in all cases the same crystals, with the same unit-cell parameters. The main assumption is that the benserazide hydro­chloride has undergone a fundamental structure transformation during the aqueous recrystallization assays, but work is in progress to understand the mechanism, which does not seem to be obvious. Compound (I)[link] could also be a by-product coming from a earlier step in the benserazide synthesis process (even if the qu­antity of crystalline material retrieved is relatively important). A calorimetric study has been undertaken on the crystalline material, and differential scanning calorimetry (DSC) provides an onset temperature (considered as the melting point) of 419.3 K, with no significant endo- or exothermic event before the fusion point. No spontaneous recrystallization occurs when the melt is allowed to cool down.

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2[link]. The methyl H atoms were located from difference Fourier maps and their positions refined freely. All other H atoms were placed at idealized positions and allowed to ride on their parent atoms, with C—H distances of 0.93 Å and with Uiso(H) = 1.2Ueq(C).

Table 2
Experimental details

Crystal data
Chemical formula C20H16N2O
Mr 300.35
Crystal system, space group Triclinic, P[\overline{1}]
Temperature (K) 293
a, b, c (Å) 7.8858 (5), 7.9226 (8), 13.0182 (13)
α, β, γ (°) 104.267 (9), 103.576 (7), 91.967 (7)
V3) 762.54 (13)
Z 2
Radiation type Mo Kα
μ (mm−1) 0.08
Crystal size (mm) 0.5 × 0.35 × 0.25
 
Data collection
Diffractometer Oxford Diffraction Xcalibur (Ruby, Gemini) ultra
Absorption correction Multi-scan (CrysAlis PRO; Oxford Diffraction, 2006[Oxford Diffraction (2006). CrysAlis PRO. Oxford Diffraction Ltd, Abingdon, England.])
Tmin, Tmax 0.960, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections 3234, 2207, 1707
Rint 0.024
(sin θ/λ)max−1) 0.595
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.046, 0.133, 1.03
No. of reflections 2256
No. of parameters 232
No. of restraints 6
H-atom treatment H atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3) 0.18, −0.14
Computer programs: CrysAlis PRO (Oxford Diffraction, 2006[Oxford Diffraction (2006). CrysAlis PRO. Oxford Diffraction Ltd, Abingdon, England.]), SIR92 (Altomare et al., 1994[Altomare, A., Cascarano, G., Giacovazzo, C., Guagliardi, A., Burla, M. C., Polidori, G. & Camalli, M. (1994). J. Appl. Cryst. 27, 435.]), SHELXL97 (Sheldrick, 2015[Sheldrick, G. M. (2015). Acta Cryst. C71, 3-8.]), ORTEPIII (Burnett & Johnson, 1996[Burnett, M. N. & Johnson, C. K. (1996). ORTEPIII. Report ORNL-6895. Oak Ridge National Laboratory, Tennessee, USA.]), PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]) and Mercury (Macrae et al., 2006[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.]).

Supporting information


Chemical context top

Parkinson's disease is a degenerative disorder of the central nervous system, resulting from the death of dopamine-generating cells, mostly located in the mid-brain. The most obvious symptoms are movement-related: uncontrolled shaking, rigidity, slowness of movement and difficulty in walking. However, behavioral problems and psychiatric depression may also arise (Samii et al., 2004). Symptomatic treatment of Parkinson's disease includes daily dopamine administration, principally through L-DOPA (or levodopa) or carbidopa (both being precursors of dopamine) brain metabolization.

Benserazide [also called Serazide or Ro–4–4602, (II) in the Scheme] is an aromatic L-amino acid de­carboxyl­ase inhibitor and a DOPA de­carboxyl­ase inhibitor unable to cross the blood–brain barrier. It is used in combination with levodopa for the symptomatic management of Parkinson's disease (Clark et al., 1973; Campanella & Pennetta, 1974; Bortolanza et al., 2015).

As benserazide is always administered in combination therapy, it appeared to be a good candidate to search for a solid-state crystalline phase involving it with another therapeutic molecule, also active in the treatment of Parkinson's disease. However, little information could be retrieved on the structural aspects of benserazide and, as a first step, recrystallization attempts of the molecule alone have been launched. These crystallization assays have been so far fruitless, but resulted instead in the unwitting obtention of a new molecule, 2,2'-oxybis(4-methyl­quinoline) (C20H16ON2), (I), which is reported herein.

Structural commentary top

The geometry of (I) is fairly predi­cta­ble, with all bond lengths and valence angles being in the expected range for organic compounds (Allen et al., 1987). The molecule consists of two planar 4-methyl­quinoline aromatic moieties [the maximum deviations from the least-squares plane are 0.0104 (18) Å for C1 in the N1,C1–C9 moiety and 0.016 (2) Å for C13 in the N2,C11–C19 unit], almost perpendicular to each other [dihedral angle = 89.5 (2)°] and bound by an oxygen atom which forms an ether link (Fig. 1).

Supra­molecular features top

The crystal packing organization is essentially the result of two different types of π-stacking inter­actions involving inversion-related molecules. Table 1 gives a survey of these ππ stacking inter­actions, in one case around (1/2, 1/2, 1/2) (Fig. 2) and in the other case around (0, 0,0 );(1, 1, 1) (Fig. 3). The overall effect of these inter­actions is the formation of chains parallel to [111] (Fig. 4). As expected from the lack of efficient hydrogen-bond donors, no significant hydrogen bonds linking the chains are present in the structure, as a result of which their mutual inter­action is rather weak.

Database survey top

A systematic research in the Cambridge Structural Database (CSD; Version 5.35, update November 2014; Groom & Allen, 2014) using ConQuest (Bruno et al., (2002) revealed some structures fairly similar to (I), which are presented in Fig. 5 and identified by their CSD refcodes: MOSLAI (Hassan et al., 2009) and JUBRAZ (Liu et al., 1992), the main difference residing in the number and relative position of the nitro­gen atoms in the aromatic rings.

Synthesis and crystallization top

Prismatic colourless crystals of 4-methyl-2-[(1-methyl­isoquinolin-3-yl)­oxy]quinoline were grown from a 2 ml aqueous saturated solution of benserazide hydro­chloride (purchased from Sigma-Aldrich, Steinheim, Germany; purity level claimed > 98%) (9.3 mg) allowed to evaporate slowly at room temperature over 7 days.

Several trials of slow evaporation of aqueous solutions under different temperature conditions (from 277 to 313 K) provided in all cases the same crystals, with the same unit-cell parameters. The main assumption is that the benserazide hydro­chloride has undergone a fundamental structure transformation during the aqueous recrystallization assays, but work is in progress to understand the mechanism, which does not seem to be obvious. Compound (I) could also be a by-product coming from a earlier step in the benserazide synthesis process (even if the qu­antity of crystalline material retrieved is really important). A calorimetric study has been undertaken on the crystalline material, and differential scanning calorimetry (DSC) provides an onset temperature (considered as the melting point) of 419.3 K, with no significant endo- or exothermic event before the fusion point. No spontaneous recrystallization occurs when the melt is allowed to cool down.

Refinement top

Crystal data, data collection and structure refinement details are summarized in Table 2. The methyl H atoms were located from difference Fourier maps and their positions refined freely. All other H atoms were placed at idealized positions and allowed to ride on their parent atoms, with C—H distances of 0.93 Å and with Uiso(H) = 1.2Ueq(C).

Related literature top

For related literature, see: Allen (2002); Allen et al. (1987); Bortolanza et al. (2015); Bruno et al. (2002); Campanella & Pennetta (1974); Clark et al. (1973); Hassan et al. (2009); Liu et al. (1992); Samii et al. (2004).

Computing details top

Data collection: CrysAlis PRO (Oxford Diffraction, 2006); cell refinement: CrysAlis PRO (Oxford Diffraction, 2006); data reduction: CrysAlis PRO (Oxford Diffraction, 2006); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: SHELXL97 (Sheldrick, 2015); molecular graphics: ORTEPIII (Burnett & Johnson, 1996), PLATON (Spek, 2009) and Mercury (Macrae et al., 2006); software used to prepare material for publication: SHELXL97 (Sheldrick, 2015).

Figures top
[Figure 1] Fig. 1. The molecular structure and atom numbering of the title compound. Displacement ellipsoids for the non-H atoms are drawn at the 50% probability level.
[Figure 2] Fig. 2. Packing diagram showing one of the ππ interactions, stacked around (1/2, 1/2, 1/2).
[Figure 3] Fig. 3. Packing diagram showing the second type of ππ interaction, stacked around (1, 1, 1).
[Figure 4] Fig. 4. The [111] chain resulting from the two types of ππ interactions.
[Figure 5] Fig. 5. Two similar structures existing in the CSD [refcodes MOSLAI (Hassan et al., 2009) and JUBRAZ (Liu et al., 1992)].
2,2'-Oxybis(4-methylquinoline) top
Crystal data top
C20H16N2OZ = 2
Mr = 300.35F(000) = 316
Triclinic, P1Dx = 1.308 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 7.8858 (5) ÅCell parameters from 1411 reflections
b = 7.9226 (8) Åθ = 3.7–28.7°
c = 13.0182 (13) ŵ = 0.08 mm1
α = 104.267 (9)°T = 293 K
β = 103.576 (7)°Prism, colourless
γ = 91.967 (7)°0.5 × 0.35 × 0.25 mm
V = 762.54 (13) Å3
Data collection top
Oxford Diffraction Xcalibur (Ruby, Gemini) ultra
diffractometer
2207 independent reflections
Radiation source: fine-focus sealed tube1707 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.024
Detector resolution: 10.3712 pixels mm-1θmax = 25.0°, θmin = 3.5°
ω scansh = 79
Absorption correction: multi-scan
(CrysAlis PRO; Oxford Diffraction, 2006)
k = 95
Tmin = 0.960, Tmax = 1.000l = 1415
3234 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)] = 0.046Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.133H atoms treated by a mixture of independent and constrained refinement
S = 1.03 w = 1/[σ2(Fo2) + (0.0652P)2 + 0.0421P]
where P = (Fo2 + 2Fc2)/3
2256 reflections(Δ/σ)max < 0.001
232 parametersΔρmax = 0.18 e Å3
6 restraintsΔρmin = 0.14 e Å3
0 constraints
Crystal data top
C20H16N2Oγ = 91.967 (7)°
Mr = 300.35V = 762.54 (13) Å3
Triclinic, P1Z = 2
a = 7.8858 (5) ÅMo Kα radiation
b = 7.9226 (8) ŵ = 0.08 mm1
c = 13.0182 (13) ÅT = 293 K
α = 104.267 (9)°0.5 × 0.35 × 0.25 mm
β = 103.576 (7)°
Data collection top
Oxford Diffraction Xcalibur (Ruby, Gemini) ultra
diffractometer
2207 independent reflections
Absorption correction: multi-scan
(CrysAlis PRO; Oxford Diffraction, 2006)
1707 reflections with I > 2σ(I)
Tmin = 0.960, Tmax = 1.000Rint = 0.024
3234 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0466 restraints
wR(F2) = 0.133H atoms treated by a mixture of independent and constrained refinement
S = 1.03Δρmax = 0.18 e Å3
2256 reflectionsΔρmin = 0.14 e Å3
232 parameters
Special details top

Experimental. Absorption correction: CrysAlis PRO, Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.

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
O10.13084 (17)0.38253 (18)0.26211 (12)0.0696 (5)
N10.01449 (17)0.1056 (2)0.20704 (12)0.0470 (4)
N20.38771 (19)0.2735 (2)0.32211 (12)0.0530 (4)
C10.0147 (2)0.2537 (2)0.18566 (15)0.0482 (5)
C20.0638 (2)0.2993 (3)0.08862 (16)0.0507 (5)
C30.1801 (2)0.1811 (3)0.00729 (15)0.0458 (5)
C40.2184 (2)0.0150 (2)0.02535 (13)0.0415 (4)
C50.1336 (2)0.0165 (2)0.12652 (14)0.0413 (4)
C60.3353 (2)0.1194 (3)0.05297 (16)0.0535 (5)
C70.3664 (2)0.2761 (3)0.03220 (18)0.0626 (6)
C80.2839 (2)0.3060 (3)0.06810 (18)0.0599 (6)
C90.1692 (2)0.1786 (3)0.14565 (16)0.0528 (5)
C100.2614 (3)0.2203 (4)0.09923 (19)0.0620 (6)
C110.2483 (2)0.3332 (2)0.34593 (15)0.0506 (5)
C120.2112 (2)0.3641 (3)0.44746 (18)0.0560 (5)
C130.3299 (3)0.3308 (2)0.53294 (16)0.0535 (5)
C140.4866 (2)0.2617 (2)0.51214 (15)0.0479 (5)
C150.5100 (2)0.2357 (2)0.40549 (15)0.0472 (5)
C160.6200 (3)0.2177 (3)0.59128 (18)0.0655 (6)
C170.7657 (3)0.1528 (3)0.5655 (2)0.0808 (8)
C180.7892 (3)0.1314 (3)0.4606 (2)0.0797 (7)
C190.6640 (3)0.1713 (3)0.38176 (19)0.0644 (6)
C200.2972 (4)0.3663 (4)0.6447 (2)0.0863 (8)
H20.03600.40950.08040.061*
H60.39200.10090.11990.064*
H70.44320.36390.08520.075*
H80.30710.41280.08210.072*
H90.11400.19980.21200.063*
H10A0.386 (3)0.211 (3)0.1129 (17)0.070 (6)*
H10B0.229 (3)0.137 (3)0.159 (2)0.081 (7)*
H10C0.219 (3)0.337 (4)0.100 (2)0.096 (8)*
H120.10620.40720.45720.067*
H160.60780.23340.66230.079*
H170.85110.12220.61860.097*
H180.89120.08950.44460.096*
H190.68010.15600.31160.077*
H20A0.186 (2)0.408 (3)0.648 (3)0.137 (12)*
H20B0.306 (3)0.259 (3)0.669 (3)0.140 (12)*
H20C0.389 (3)0.451 (3)0.698 (2)0.129 (11)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0706 (9)0.0484 (9)0.0657 (10)0.0002 (6)0.0204 (7)0.0072 (7)
N10.0449 (9)0.0537 (10)0.0366 (9)0.0033 (7)0.0035 (6)0.0079 (8)
N20.0590 (11)0.0537 (10)0.0368 (9)0.0031 (8)0.0042 (7)0.0023 (8)
C10.0407 (10)0.0487 (11)0.0465 (12)0.0059 (8)0.0027 (8)0.0042 (10)
C20.0466 (11)0.0502 (11)0.0542 (12)0.0094 (8)0.0066 (9)0.0165 (10)
C30.0375 (10)0.0618 (12)0.0397 (10)0.0139 (8)0.0099 (7)0.0146 (10)
C40.0333 (10)0.0552 (11)0.0349 (10)0.0071 (7)0.0105 (7)0.0072 (9)
C50.0361 (10)0.0496 (11)0.0371 (10)0.0041 (7)0.0116 (7)0.0072 (9)
C60.0456 (11)0.0677 (14)0.0384 (11)0.0031 (9)0.0054 (8)0.0030 (10)
C70.0480 (12)0.0649 (14)0.0609 (14)0.0080 (9)0.0089 (9)0.0032 (12)
C80.0537 (13)0.0568 (13)0.0692 (15)0.0040 (9)0.0203 (10)0.0128 (12)
C90.0479 (11)0.0644 (13)0.0487 (12)0.0016 (9)0.0140 (8)0.0182 (11)
C100.0562 (15)0.0813 (18)0.0507 (14)0.0172 (12)0.0076 (10)0.0254 (13)
C110.0506 (12)0.0446 (11)0.0432 (12)0.0029 (8)0.0034 (9)0.0026 (9)
C120.0456 (11)0.0517 (12)0.0681 (14)0.0010 (8)0.0162 (9)0.0099 (11)
C130.0682 (13)0.0445 (11)0.0459 (12)0.0100 (9)0.0213 (9)0.0035 (9)
C140.0535 (12)0.0425 (11)0.0406 (11)0.0094 (8)0.0038 (8)0.0074 (9)
C150.0476 (11)0.0448 (11)0.0422 (11)0.0021 (8)0.0064 (8)0.0042 (9)
C160.0767 (15)0.0604 (13)0.0480 (13)0.0077 (11)0.0051 (10)0.0151 (11)
C170.0659 (16)0.0710 (16)0.086 (2)0.0015 (12)0.0221 (13)0.0247 (15)
C180.0536 (14)0.0674 (16)0.108 (2)0.0078 (10)0.0065 (13)0.0165 (15)
C190.0631 (14)0.0631 (14)0.0649 (14)0.0069 (10)0.0185 (10)0.0107 (11)
C200.118 (2)0.087 (2)0.0657 (18)0.0003 (17)0.0483 (16)0.0180 (16)
Geometric parameters (Å, º) top
O1—C11.371 (2)C10—H10C0.97 (3)
O1—C111.401 (2)C10—H10A0.95 (2)
N1—C11.296 (2)C10—H10B0.97 (3)
N1—C51.376 (2)C11—C121.386 (3)
N2—C111.285 (2)C12—H120.9300
N2—C151.373 (2)C13—C121.363 (3)
C2—C31.355 (3)C13—C201.497 (3)
C2—C11.408 (2)C14—C161.408 (3)
C2—H20.9300C14—C151.409 (3)
C3—C101.496 (3)C14—C131.426 (3)
C4—C61.407 (3)C15—C191.404 (3)
C4—C31.427 (3)C16—C171.354 (3)
C5—C91.398 (2)C16—H160.9300
C5—C41.416 (2)C17—H170.9300
C6—C71.360 (3)C18—C171.391 (4)
C6—H60.9300C18—H180.9300
C7—H70.9300C19—C181.354 (3)
C8—C71.396 (3)C19—H190.9300
C8—H80.9300C20—H20A0.956 (18)
C9—C81.365 (3)C20—H20B0.981 (18)
C9—H90.9300C20—H20C0.978 (19)
O1—C1—C2114.47 (16)C9—C8—H8119.9
N1—C1—O1119.50 (16)C11—N2—C15116.43 (16)
N1—C1—C2126.03 (17)C11—C12—H12120.3
N1—C5—C9118.13 (16)C12—C11—O1118.03 (18)
N1—C5—C4122.58 (15)C12—C13—C14117.55 (18)
N2—C11—C12126.19 (17)C12—C13—C20121.2 (2)
N2—C11—O1115.61 (18)C13—C12—C11119.38 (18)
N2—C15—C19117.56 (18)C13—C12—H12120.3
N2—C15—C14122.48 (17)C13—C20—H20A113.8 (19)
C1—O1—C11117.49 (14)C13—C20—H20B109 (2)
C1—N1—C5116.00 (15)C13—C20—H20C111.1 (18)
C1—C2—H2120.3C14—C13—C20121.2 (2)
C2—C3—C4117.60 (16)C14—C16—H16119.5
C2—C3—C10121.44 (19)C15—C14—C13117.96 (16)
C3—C2—C1119.35 (17)C15—C19—H19119.9
C3—C2—H2120.3C16—C14—C15117.77 (19)
C3—C10—H10A110.7 (12)C16—C14—C13124.27 (19)
C3—C10—H10B109.6 (13)C16—C17—C18120.8 (2)
C3—C10—H10C111.3 (14)C16—C17—H17119.6
C4—C3—C10120.92 (19)C17—C16—C14121.0 (2)
C4—C6—H6119.5C17—C16—H16119.5
C5—C4—C3118.42 (17)C17—C18—H18119.9
C5—C9—H9119.6C18—C17—H17119.6
C6—C4—C5118.45 (17)C18—C19—C15120.2 (2)
C6—C4—C3123.13 (16)C18—C19—H19119.9
C6—C7—C8120.43 (19)C19—C15—C14119.95 (17)
C6—C7—H7119.8C19—C18—C17120.3 (2)
C7—C6—C4120.92 (18)C19—C18—H18119.9
C7—C6—H6119.5H10A—C10—H10B108.5 (18)
C7—C8—H8119.9H10C—C10—H10A109.4 (17)
C8—C7—H7119.8H10C—C10—H10B107 (2)
C8—C9—C5120.81 (18)H20A—C20—H20B109.3 (18)
C8—C9—H9119.6H20A—C20—H20C108.4 (19)
C9—C5—C4119.28 (17)H20B—C20—H20C104.8 (17)
C9—C8—C7120.11 (18)
O1—C11—C12—C13174.70 (15)C9—C5—C4—C3179.86 (14)
N1—C5—C4—C6178.55 (15)C9—C8—C7—C60.9 (3)
N1—C5—C4—C30.9 (3)C11—O1—C1—N117.5 (3)
N1—C5—C9—C8178.88 (17)C11—O1—C1—C2162.77 (16)
N2—C15—C19—C18179.87 (19)C11—N2—C15—C19179.60 (17)
C1—O1—C11—N283.6 (2)C11—N2—C15—C140.5 (3)
C1—O1—C11—C12100.8 (2)C13—C14—C15—C19178.68 (16)
C1—N1—C5—C9179.85 (15)C13—C14—C15—N20.4 (3)
C1—N1—C5—C40.9 (3)C13—C14—C16—C17179.87 (19)
C1—C2—C3—C40.6 (3)C14—C13—C12—C111.2 (3)
C1—C2—C3—C10177.41 (18)C14—C15—C19—C181.0 (3)
C3—C2—C1—N10.7 (3)C14—C16—C17—C181.4 (3)
C3—C2—C1—O1179.64 (16)C15—N2—C11—C120.6 (3)
C3—C4—C6—C7179.46 (16)C15—N2—C11—O1175.70 (14)
C4—C5—C9—C80.1 (3)C15—C14—C13—C121.2 (2)
C4—C6—C7—C80.6 (3)C15—C14—C13—C20178.48 (19)
C5—C4—C3—C10178.14 (17)C15—C14—C16—C170.1 (3)
C5—N1—C1—O1179.57 (16)C15—C19—C18—C170.4 (3)
C5—N1—C1—C20.1 (3)C16—C14—C15—N2179.68 (16)
C5—C4—C3—C20.1 (3)C16—C14—C15—C191.3 (3)
C5—C4—C6—C70.0 (3)C16—C14—C13—C12178.83 (17)
C5—C9—C8—C70.5 (3)C16—C14—C13—C201.4 (3)
C6—C4—C3—C2179.31 (16)C19—C18—C17—C161.6 (4)
C6—C4—C3—C101.3 (3)C20—C13—C12—C11178.5 (2)
C9—C5—C4—C60.4 (3)
ππ stacking interactions (Å, °) top
Cg1, Cg2, Cg3 and Cg4 are the centroids of the N1/C1–C5, N2/C11–C15, C4–C9 and C14–C19 rings, respectively. Cg···Cg is the intercentroid distance, the dihedral angle is between the ring planes and mpd is the mean perpendicular distance between a centroid and the opposite plane.
Cg···Cgdihedral anglempd
Cg1···Cg1i3.7849 (11)03.4446 (7)
Cg1···Cg3i3.7775 (11)0.83 (8)3.4345 (10)
Cg2···Cg2ii3.6036 (11)03.4395 (7)
Cg2···Cg4ii3.8817 (12)0.73 (10)3.4462 (19)
Symmetry codes: (i) -x, -y, -z; (ii) 1 - x, 1 - y, 1 - z.

Experimental details

Crystal data
Chemical formulaC20H16N2O
Mr300.35
Crystal system, space groupTriclinic, P1
Temperature (K)293
a, b, c (Å)7.8858 (5), 7.9226 (8), 13.0182 (13)
α, β, γ (°)104.267 (9), 103.576 (7), 91.967 (7)
V3)762.54 (13)
Z2
Radiation typeMo Kα
µ (mm1)0.08
Crystal size (mm)0.5 × 0.35 × 0.25
Data collection
DiffractometerOxford Diffraction Xcalibur (Ruby, Gemini) ultra
diffractometer
Absorption correctionMulti-scan
(CrysAlis PRO; Oxford Diffraction, 2006)
Tmin, Tmax0.960, 1.000
No. of measured, independent and
observed [I > 2σ(I)] reflections
3234, 2207, 1707
Rint0.024
(sin θ/λ)max1)0.595
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.046, 0.133, 1.03
No. of reflections2256
No. of parameters232
No. of restraints6
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.18, 0.14

Computer programs: CrysAlis PRO (Oxford Diffraction, 2006), SIR92 (Altomare et al., 1994), SHELXL97 (Sheldrick, 2015), ORTEPIII (Burnett & Johnson, 1996), PLATON (Spek, 2009) and Mercury (Macrae et al., 2006).

 

Acknowledgements

This work was supported by the Fonds National de la Recherche Scientifique (FRS–FNRS, Belgium). AT acknowledges Professor J. Wouters and B. Norberg for their fruitful work and input to the project.

References

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Volume 71| Part 2| February 2015| Pages 180-183
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