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Acta Crystallographica Section E: Structure Reports Online logoLink to Acta Crystallographica Section E: Structure Reports Online
. 2009 May 20;65(Pt 6):o1332. doi: 10.1107/S1600536809017759

1,1′,2,2′-Tetra­methyl-3,3′-(4-methoxy­benzyl­idene)di-1H-indole

Cai-Li Zhang a, Ping-Ping Ye a, Zhi-Qiang Du a,*
PMCID: PMC2969556  PMID: 21583186

Abstract

The title compound, C28H28N2O, was prepared by condensation of 1,2-bimethyl­indole and 4-methoxy­benzaldehyde. In the mol­ecular structure, the plane of the non-fused benzene ring is twisted with respect to the planes of the two indole ring systems, exhibiting dihedral angles of 72.04 (7) and 72.24 (7)°, while the planes of the two indole ring systems are oriented at a dihedral angle of 87.05 (5)°. Neither hydrogen bonding nor π–π stacking is observed in the crystal structure.

Related literature

For general background to the physiological properties of indole derivatives, see: Poter et al. (1977); Sundberg (1996). For related structures, see: Chang et al. (1999); Ge et al. (1999); Morris & Andersen (1990); Azizian et al. (2007); Osawa & Namiki (1983). For the synthesis, see: Deb & Bhuyan (2006).graphic file with name e-65-o1332-scheme1.jpg

Experimental

Crystal data

  • C28H28N2O

  • M r = 408.52

  • Monoclinic, Inline graphic

  • a = 10.6647 (8) Å

  • b = 13.2088 (10) Å

  • c = 16.1494 (13) Å

  • β = 97.1740 (10)°

  • V = 2257.1 (3) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.07 mm−1

  • T = 296 K

  • 0.25 × 0.24 × 0.21 mm

Data collection

  • Bruker SMART CCD area-detector diffractometer

  • Absorption correction: none

  • 11505 measured reflections

  • 3955 independent reflections

  • 3196 reflections with I > 2σ(I)

  • R int = 0.025

Refinement

  • R[F 2 > 2σ(F 2)] = 0.044

  • wR(F 2) = 0.139

  • S = 0.83

  • 3955 reflections

  • 285 parameters

  • H-atom parameters constrained

  • Δρmax = 0.21 e Å−3

  • Δρmin = −0.22 e Å−3

Data collection: SMART (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT; 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); software used to prepare material for publication: WinGX (Farrugia, 1999).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809017759/xu2523sup1.cif

e-65-o1332-sup1.cif (20.1KB, cif)

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809017759/xu2523Isup2.hkl

e-65-o1332-Isup2.hkl (189.9KB, hkl)

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

Acknowledgments

The work was supported by the National Natural Science Foundation of China (grant No. 20376071).

supplementary crystallographic information

Comment

Indole derivatives are found abundantly in a variety of natural plants and exhibit various physiological properties (Poter et al., 1977; Sundberg, 1996). Among them, bis-indolymethane derivatives are found to be kinds of potentially bioactive compounds (Chang et al., 1999; Ge et al., 1999). In recent years, the synthesis and application of bis-indolymethane derivatives have been widely studied (Osawa & Namiki, 1983; Morris & Andersen, 1990; Azizian et al., 2007). The title compound is one of bis-indolymethane derivatives. We report here its crystal structure.

The molecular structure of the title compound is shown in Fig. 1. The C2-benzene ring is twisted to the two indole rings with the dihedral angles of 72.04 (7)° and 72.24 (7)°, respectively. Two indole rings make a dihedral angle of 87.86 (3)° to each other. Neither hydrogen bonding nor π-π stacking is observed in the crystal structure.

Experimental

The title compound was prepared according to the procedure reported by Deb & Bhuyan (2006). 1,2-Bimethylindole (2.0 mmol) and p-methoxybenzaldehyde (1.0 mmol) were dissolved in methanol (5 ml). The solution was stirred at room temperature for 5 h, then the solvent was removed under vacuum and the crude product was purified by silica-gel flash column chromatography. Single crystals suitable for X-ray data collection were obtained by recrystallization from chloroform/hexane.

Refinement

H atoms were located geometrically and treated as riding, with C—H = 0.93 (aromatic), 0.96 (methyl) and 0.98 Å (methine), and Uiso(H) = 1.5Ueq(C) for methyl and 1.2Ueq(C) for the others.

Figures

Fig. 1.

Fig. 1.

The molecular structure of (I) with 30% probability displacement ellipsoids.

Crystal data

C28H28N2O F(000) = 872
Mr = 408.52 Dx = 1.202 Mg m3
Monoclinic, P21/n Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn Cell parameters from 6354 reflections
a = 10.6647 (8) Å θ = 4.9–51.2°
b = 13.2088 (10) Å µ = 0.07 mm1
c = 16.1494 (13) Å T = 296 K
β = 97.174 (1)° Prism, colorless
V = 2257.1 (3) Å3 0.25 × 0.24 × 0.21 mm
Z = 4

Data collection

Bruker SMART CCD area-detector diffractometer 3196 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube Rint = 0.025
graphite θmax = 25.0°, θmin = 2.0°
φ and ω scans h = −12→12
11505 measured reflections k = −15→15
3955 independent reflections l = −19→19

Refinement

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)] = 0.044 Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.139 H-atom parameters constrained
S = 0.83 w = 1/[σ2(Fo2) + (0.1047P)2 + 0.8752P] where P = (Fo2 + 2Fc2)/3
3955 reflections (Δ/σ)max < 0.001
285 parameters Δρmax = 0.21 e Å3
0 restraints Δρmin = −0.22 e Å3

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)

x y z Uiso*/Ueq
N1 0.63286 (14) 0.32330 (11) 0.89904 (8) 0.0421 (4)
N2 0.23060 (12) 0.47645 (10) 0.62297 (8) 0.0358 (3)
O1 0.73808 (18) 0.09952 (13) 0.43460 (10) 0.0827 (5)
C1 0.54764 (14) 0.35901 (11) 0.67122 (9) 0.0316 (3)
H1 0.5937 0.4226 0.6671 0.038*
C2 0.59177 (14) 0.28915 (11) 0.60516 (9) 0.0334 (4)
C3 0.72045 (16) 0.27569 (12) 0.60290 (11) 0.0403 (4)
H3 0.7776 0.3097 0.6414 0.048*
C4 0.76556 (18) 0.21341 (14) 0.54521 (12) 0.0501 (5)
H4 0.8522 0.2066 0.5446 0.060*
C5 0.6831 (2) 0.16106 (14) 0.48826 (12) 0.0529 (5)
C6 0.5550 (2) 0.17324 (15) 0.48860 (12) 0.0544 (5)
H6 0.4984 0.1387 0.4502 0.065*
C7 0.51073 (17) 0.23765 (13) 0.54694 (11) 0.0435 (4)
H7 0.4240 0.2460 0.5464 0.052*
C8 0.6598 (4) 0.0526 (3) 0.36972 (17) 0.1146 (13)
H8A 0.7107 0.0159 0.3349 0.172*
H8B 0.6113 0.1031 0.3371 0.172*
H8C 0.6036 0.0066 0.3927 0.172*
C9 0.58732 (14) 0.32027 (11) 0.75930 (9) 0.0319 (3)
C10 0.62303 (14) 0.21961 (11) 0.78731 (10) 0.0317 (3)
C11 0.63396 (15) 0.12468 (12) 0.74924 (10) 0.0373 (4)
H11 0.6147 0.1177 0.6918 0.045*
C12 0.67336 (16) 0.04226 (12) 0.79772 (11) 0.0423 (4)
H12 0.6806 −0.0203 0.7724 0.051*
C13 0.70262 (16) 0.05046 (13) 0.88377 (11) 0.0446 (4)
H13 0.7297 −0.0065 0.9148 0.054*
C14 0.69222 (16) 0.14123 (14) 0.92376 (11) 0.0428 (4)
H14 0.7117 0.1467 0.9813 0.051*
C15 0.65141 (14) 0.22480 (12) 0.87502 (10) 0.0355 (4)
C16 0.59485 (15) 0.38016 (12) 0.82871 (10) 0.0377 (4)
C17 0.6468 (2) 0.35910 (17) 0.98459 (12) 0.0627 (6)
H17A 0.6664 0.3030 1.0218 0.094*
H17B 0.5693 0.3901 0.9960 0.094*
H17C 0.7139 0.4079 0.9926 0.094*
C18 0.5666 (2) 0.49042 (14) 0.83534 (13) 0.0561 (5)
H18A 0.6390 0.5245 0.8638 0.084*
H18B 0.4958 0.4992 0.8660 0.084*
H18C 0.5467 0.5185 0.7804 0.084*
C19 0.40945 (14) 0.38686 (11) 0.65659 (9) 0.0314 (3)
C20 0.30467 (14) 0.32631 (11) 0.67439 (9) 0.0325 (4)
C21 0.29216 (16) 0.22881 (12) 0.70659 (10) 0.0395 (4)
H21 0.3633 0.1891 0.7218 0.047*
C22 0.17413 (17) 0.19248 (14) 0.71551 (11) 0.0455 (4)
H22 0.1659 0.1277 0.7368 0.055*
C23 0.06594 (17) 0.25115 (15) 0.69312 (12) 0.0484 (4)
H23 −0.0130 0.2249 0.7000 0.058*
C24 0.07467 (16) 0.34710 (14) 0.66114 (11) 0.0438 (4)
H24 0.0028 0.3859 0.6458 0.053*
C25 0.19443 (15) 0.38423 (12) 0.65254 (9) 0.0339 (4)
C26 0.36095 (14) 0.47703 (11) 0.62486 (9) 0.0322 (3)
C27 0.14395 (17) 0.55850 (14) 0.59566 (12) 0.0477 (4)
H27A 0.0825 0.5654 0.6340 0.072*
H27B 0.1018 0.5437 0.5410 0.072*
H27C 0.1904 0.6206 0.5940 0.072*
C28 0.42723 (17) 0.56692 (13) 0.59485 (11) 0.0440 (4)
H28A 0.4049 0.6263 0.6240 0.066*
H28B 0.4025 0.5756 0.5361 0.066*
H28C 0.5169 0.5566 0.6051 0.066*

Atomic displacement parameters (Å2)

U11 U22 U33 U12 U13 U23
N1 0.0508 (8) 0.0427 (8) 0.0313 (7) 0.0060 (6) −0.0012 (6) −0.0044 (6)
N2 0.0330 (7) 0.0350 (7) 0.0386 (7) 0.0063 (5) 0.0018 (6) 0.0039 (6)
O1 0.1152 (14) 0.0747 (11) 0.0624 (10) 0.0308 (10) 0.0278 (9) −0.0145 (8)
C1 0.0315 (8) 0.0275 (8) 0.0353 (8) −0.0008 (6) 0.0018 (6) 0.0037 (6)
C2 0.0382 (9) 0.0299 (8) 0.0324 (8) 0.0016 (6) 0.0052 (6) 0.0063 (6)
C3 0.0371 (9) 0.0382 (9) 0.0457 (10) 0.0028 (7) 0.0058 (7) 0.0039 (7)
C4 0.0499 (11) 0.0477 (11) 0.0557 (11) 0.0115 (8) 0.0177 (9) 0.0075 (9)
C5 0.0758 (14) 0.0434 (10) 0.0417 (10) 0.0161 (9) 0.0160 (9) 0.0026 (8)
C6 0.0690 (13) 0.0507 (11) 0.0416 (10) 0.0012 (9) −0.0004 (9) −0.0076 (8)
C7 0.0432 (9) 0.0474 (10) 0.0390 (9) 0.0005 (7) 0.0012 (7) −0.0003 (8)
C8 0.173 (3) 0.112 (2) 0.0558 (15) 0.059 (2) 0.0022 (18) −0.0304 (16)
C9 0.0294 (7) 0.0305 (8) 0.0347 (8) 0.0012 (6) −0.0007 (6) 0.0008 (6)
C10 0.0281 (7) 0.0323 (8) 0.0339 (8) 0.0007 (6) 0.0008 (6) 0.0018 (6)
C11 0.0414 (9) 0.0336 (8) 0.0366 (9) 0.0005 (7) 0.0037 (7) 0.0017 (7)
C12 0.0446 (9) 0.0316 (8) 0.0514 (10) 0.0054 (7) 0.0089 (8) 0.0044 (7)
C13 0.0410 (9) 0.0411 (10) 0.0516 (11) 0.0064 (7) 0.0047 (8) 0.0156 (8)
C14 0.0398 (9) 0.0508 (10) 0.0366 (9) 0.0029 (8) −0.0005 (7) 0.0085 (8)
C15 0.0337 (8) 0.0380 (9) 0.0338 (8) 0.0024 (7) 0.0001 (6) 0.0012 (7)
C16 0.0391 (9) 0.0338 (9) 0.0391 (9) 0.0042 (7) 0.0007 (7) −0.0020 (7)
C17 0.0839 (15) 0.0651 (13) 0.0362 (10) 0.0102 (11) −0.0041 (10) −0.0105 (9)
C18 0.0727 (14) 0.0391 (10) 0.0550 (12) 0.0119 (9) 0.0018 (10) −0.0095 (9)
C19 0.0324 (8) 0.0320 (8) 0.0294 (8) 0.0011 (6) 0.0024 (6) 0.0019 (6)
C20 0.0337 (8) 0.0337 (8) 0.0295 (8) 0.0006 (6) 0.0020 (6) 0.0000 (6)
C21 0.0385 (9) 0.0373 (9) 0.0416 (9) −0.0008 (7) 0.0011 (7) 0.0051 (7)
C22 0.0453 (10) 0.0423 (10) 0.0485 (10) −0.0090 (8) 0.0048 (8) 0.0065 (8)
C23 0.0375 (9) 0.0545 (11) 0.0536 (11) −0.0099 (8) 0.0079 (8) 0.0008 (9)
C24 0.0338 (9) 0.0490 (10) 0.0481 (10) 0.0024 (7) 0.0030 (7) −0.0022 (8)
C25 0.0340 (8) 0.0365 (8) 0.0309 (8) 0.0016 (6) 0.0025 (6) −0.0013 (6)
C26 0.0335 (8) 0.0326 (8) 0.0305 (8) 0.0023 (6) 0.0036 (6) 0.0012 (6)
C27 0.0435 (10) 0.0446 (10) 0.0535 (11) 0.0141 (8) 0.0003 (8) 0.0048 (8)
C28 0.0461 (10) 0.0368 (9) 0.0492 (10) 0.0022 (7) 0.0069 (8) 0.0103 (7)

Geometric parameters (Å, °)

N1—C15 1.379 (2) C12—H12 0.9300
N1—C16 1.380 (2) C13—C14 1.373 (3)
N1—C17 1.450 (2) C13—H13 0.9300
N2—C25 1.381 (2) C14—C15 1.394 (2)
N2—C26 1.3867 (19) C14—H14 0.9300
N2—C27 1.457 (2) C16—C18 1.494 (2)
O1—C5 1.372 (2) C17—H17A 0.9600
O1—C8 1.401 (4) C17—H17B 0.9600
C1—C19 1.509 (2) C17—H17C 0.9600
C1—C9 1.521 (2) C18—H18A 0.9600
C1—C2 1.529 (2) C18—H18B 0.9600
C1—H1 0.9800 C18—H18C 0.9600
C2—C7 1.375 (2) C19—C26 1.372 (2)
C2—C3 1.389 (2) C19—C20 1.432 (2)
C3—C4 1.374 (2) C20—C21 1.401 (2)
C3—H3 0.9300 C20—C25 1.410 (2)
C4—C5 1.377 (3) C21—C22 1.371 (2)
C4—H4 0.9300 C21—H21 0.9300
C5—C6 1.376 (3) C22—C23 1.400 (3)
C6—C7 1.395 (3) C22—H22 0.9300
C6—H6 0.9300 C23—C24 1.376 (3)
C7—H7 0.9300 C23—H23 0.9300
C8—H8A 0.9600 C24—C25 1.391 (2)
C8—H8B 0.9600 C24—H24 0.9300
C8—H8C 0.9600 C26—C28 1.493 (2)
C9—C16 1.366 (2) C27—H27A 0.9600
C9—C10 1.440 (2) C27—H27B 0.9600
C10—C11 1.408 (2) C27—H27C 0.9600
C10—C15 1.413 (2) C28—H28A 0.9600
C11—C12 1.376 (2) C28—H28B 0.9600
C11—H11 0.9300 C28—H28C 0.9600
C12—C13 1.390 (3)
C15—N1—C16 108.65 (13) N1—C15—C14 129.36 (15)
C15—N1—C17 125.05 (15) N1—C15—C10 107.91 (13)
C16—N1—C17 126.26 (15) C14—C15—C10 122.72 (15)
C25—N2—C26 108.65 (12) C9—C16—N1 109.97 (14)
C25—N2—C27 124.55 (14) C9—C16—C18 129.17 (16)
C26—N2—C27 126.80 (14) N1—C16—C18 120.86 (15)
C5—O1—C8 118.2 (2) N1—C17—H17A 109.5
C19—C1—C9 112.38 (12) N1—C17—H17B 109.5
C19—C1—C2 114.70 (13) H17A—C17—H17B 109.5
C9—C1—C2 112.06 (12) N1—C17—H17C 109.5
C19—C1—H1 105.6 H17A—C17—H17C 109.5
C9—C1—H1 105.6 H17B—C17—H17C 109.5
C2—C1—H1 105.6 C16—C18—H18A 109.5
C7—C2—C3 117.22 (15) C16—C18—H18B 109.5
C7—C2—C1 123.63 (14) H18A—C18—H18B 109.5
C3—C2—C1 119.15 (14) C16—C18—H18C 109.5
C4—C3—C2 121.69 (17) H18A—C18—H18C 109.5
C4—C3—H3 119.2 H18B—C18—H18C 109.5
C2—C3—H3 119.2 C26—C19—C20 107.00 (13)
C5—C4—C3 120.34 (18) C26—C19—C1 125.84 (14)
C5—C4—H4 119.8 C20—C19—C1 127.15 (13)
C3—C4—H4 119.8 C21—C20—C25 118.45 (14)
O1—C5—C4 115.59 (19) C21—C20—C19 134.46 (14)
O1—C5—C6 125.1 (2) C25—C20—C19 107.09 (13)
C4—C5—C6 119.35 (17) C22—C21—C20 119.45 (16)
C5—C6—C7 119.62 (18) C22—C21—H21 120.3
C5—C6—H6 120.2 C20—C21—H21 120.3
C7—C6—H6 120.2 C21—C22—C23 121.13 (17)
C2—C7—C6 121.77 (17) C21—C22—H22 119.4
C2—C7—H7 119.1 C23—C22—H22 119.4
C6—C7—H7 119.1 C24—C23—C22 120.98 (16)
O1—C8—H8A 109.5 C24—C23—H23 119.5
O1—C8—H8B 109.5 C22—C23—H23 119.5
H8A—C8—H8B 109.5 C23—C24—C25 117.91 (16)
O1—C8—H8C 109.5 C23—C24—H24 121.0
H8A—C8—H8C 109.5 C25—C24—H24 121.0
H8B—C8—H8C 109.5 N2—C25—C24 130.18 (15)
C16—C9—C10 106.89 (13) N2—C25—C20 107.76 (13)
C16—C9—C1 123.61 (14) C24—C25—C20 122.07 (15)
C10—C9—C1 129.50 (14) C19—C26—N2 109.49 (13)
C11—C10—C15 117.53 (14) C19—C26—C28 129.77 (14)
C11—C10—C9 135.90 (15) N2—C26—C28 120.74 (13)
C15—C10—C9 106.57 (13) N2—C27—H27A 109.5
C12—C11—C10 119.50 (15) N2—C27—H27B 109.5
C12—C11—H11 120.2 H27A—C27—H27B 109.5
C10—C11—H11 120.2 N2—C27—H27C 109.5
C11—C12—C13 121.45 (16) H27A—C27—H27C 109.5
C11—C12—H12 119.3 H27B—C27—H27C 109.5
C13—C12—H12 119.3 C26—C28—H28A 109.5
C14—C13—C12 121.14 (16) C26—C28—H28B 109.5
C14—C13—H13 119.4 H28A—C28—H28B 109.5
C12—C13—H13 119.4 C26—C28—H28C 109.5
C13—C14—C15 117.65 (16) H28A—C28—H28C 109.5
C13—C14—H14 121.2 H28B—C28—H28C 109.5
C15—C14—H14 121.2

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: XU2523).

References

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  2. Bruker (2004). SMART and SAINT Bruker AXS Inc., Madison, Winsonsin, USA.
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  12. Sundberg, R. J. (1996). The Chemistry of Indoles, p. 113. New York: Academic Press.

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809017759/xu2523sup1.cif

e-65-o1332-sup1.cif (20.1KB, cif)

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809017759/xu2523Isup2.hkl

e-65-o1332-Isup2.hkl (189.9KB, hkl)

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


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