Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270110053102/gg3251sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270110053102/gg3251Isup2.hkl |
CCDC reference: 817050
For related literature, see: Allen et al. (1987); Ferguson et al. (1998a, 1998b); Gerkin & Reppart (1986); Gregson et al. (2000); Perrier et al. (2004); Popova & Chetkina (1979); Tian et al. (2006); Tsutsui et al. (1976); Wan et al. (2007).
For the synthesis of compound (I), a mixture of KOH (0.02 mol) and 9H-carbazole (0.02 mol) in dimethyl sulfoxide (50 ml) was stirred vigorously at room temperature for 2 h; carbon disulfide (0.02 mol) was then added dropwise over a period of 15 min, and the mixture was stirred for a further 3 h. 1,4-Bis(chloromethyl)benzene (0.01 mol) was added to the resulting mixture, forming a yellow solution. This solution was poured into a large excess of water, and the yellow precipitate which formed was collected by filtration. Recrystallization from a dichloromethane–methanol mixture (1:1 v/v) gave yellow crystals suitable for single-crystal X-ray diffraction (yield 32%, m.p 472–473 K).
All H atoms were located in difference maps, and then treated as riding atoms in geometrically idealized positions with C—H distances of 0.95 (aromatic) or 0.99 Å (CH2), and with Uiso(H) = 1.2Ueq(C).
Data collection: COLLECT (Hooft, 1999); cell refinement: DIRAX/LSQ (Duisenberg et al., 2000); data reduction: EVALCCD (Duisenberg et al., 2003); program(s) used to solve structure: SIR2004 (Burla et al., 2005); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).
C34H24N2S4 | F(000) = 612 |
Mr = 588.83 | Dx = 1.444 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yn | Cell parameters from 3110 reflections |
a = 10.296 (2) Å | θ = 2.7–27.5° |
b = 10.0793 (19) Å | µ = 0.38 mm−1 |
c = 13.137 (2) Å | T = 120 K |
β = 96.646 (14)° | Needle, colourless |
V = 1354.2 (4) Å3 | 0.52 × 0.17 × 0.10 mm |
Z = 2 |
Bruker–Nonius KappaCCD diffractometer | 2520 independent reflections |
Radiation source: Bruker–Nonius FR591 rotating anode | 1880 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.062 |
Detector resolution: 9.091 pixels mm-1 | θmax = 25.5°, θmin = 2.7° |
ϕ and ω scans | h = −12→12 |
Absorption correction: multi-scan (SADABS; Sheldrick, 2003) | k = −12→12 |
Tmin = 0.869, Tmax = 0.963 | l = −15→15 |
15566 measured reflections |
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)] = 0.052 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.099 | H-atom parameters constrained |
S = 1.13 | w = 1/[σ2(Fo2) + (0.0292P)2 + 1.0522P] where P = (Fo2 + 2Fc2)/3 |
2520 reflections | (Δ/σ)max = 0.001 |
181 parameters | Δρmax = 0.25 e Å−3 |
0 restraints | Δρmin = −0.30 e Å−3 |
C34H24N2S4 | V = 1354.2 (4) Å3 |
Mr = 588.83 | Z = 2 |
Monoclinic, P21/n | Mo Kα radiation |
a = 10.296 (2) Å | µ = 0.38 mm−1 |
b = 10.0793 (19) Å | T = 120 K |
c = 13.137 (2) Å | 0.52 × 0.17 × 0.10 mm |
β = 96.646 (14)° |
Bruker–Nonius KappaCCD diffractometer | 2520 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 2003) | 1880 reflections with I > 2σ(I) |
Tmin = 0.869, Tmax = 0.963 | Rint = 0.062 |
15566 measured reflections |
R[F2 > 2σ(F2)] = 0.052 | 0 restraints |
wR(F2) = 0.099 | H-atom parameters constrained |
S = 1.13 | Δρmax = 0.25 e Å−3 |
2520 reflections | Δρmin = −0.30 e Å−3 |
181 parameters |
x | y | z | Uiso*/Ueq | ||
C1 | 0.0071 (3) | 0.8142 (3) | 0.3388 (2) | 0.0286 (7) | |
H1 | 0.0756 | 0.7533 | 0.3308 | 0.034* | |
C2 | −0.1208 (3) | 0.7738 (3) | 0.3284 (2) | 0.0358 (8) | |
H2 | −0.1412 | 0.6835 | 0.3136 | 0.043* | |
C3 | −0.2211 (3) | 0.8627 (4) | 0.3392 (2) | 0.0407 (8) | |
H3 | −0.3089 | 0.8319 | 0.3335 | 0.049* | |
C4 | −0.1952 (3) | 0.9937 (3) | 0.3579 (2) | 0.0363 (8) | |
H4 | −0.2644 | 1.0545 | 0.3636 | 0.044* | |
C4A | −0.0674 (3) | 1.0365 (3) | 0.36824 (19) | 0.0284 (7) | |
C4B | −0.0104 (3) | 1.1665 (3) | 0.37977 (19) | 0.0302 (7) | |
C5 | −0.0658 (3) | 1.2915 (3) | 0.3878 (2) | 0.0391 (8) | |
H5 | −0.1578 | 1.3013 | 0.3862 | 0.047* | |
C6 | 0.0135 (4) | 1.3989 (3) | 0.3980 (2) | 0.0482 (10) | |
H6 | −0.0235 | 1.4847 | 0.4029 | 0.058* | |
C7 | 0.1470 (4) | 1.3856 (3) | 0.4014 (2) | 0.0456 (9) | |
H7 | 0.2006 | 1.4624 | 0.4110 | 0.055* | |
C8 | 0.2047 (3) | 1.2638 (3) | 0.3912 (2) | 0.0369 (8) | |
H8 | 0.2967 | 1.2555 | 0.3921 | 0.044* | |
C8A | 0.1239 (3) | 1.1541 (3) | 0.37956 (19) | 0.0281 (7) | |
N9 | 0.1537 (2) | 1.0175 (2) | 0.37045 (16) | 0.0248 (5) | |
C9A | 0.0337 (3) | 0.9463 (3) | 0.36135 (19) | 0.0248 (6) | |
C10 | 0.2786 (3) | 0.9660 (3) | 0.37496 (19) | 0.0250 (6) | |
S10 | 0.40383 (8) | 1.04443 (8) | 0.33861 (6) | 0.0349 (2) | |
S11 | 0.29150 (7) | 0.80717 (7) | 0.42721 (6) | 0.0298 (2) | |
C11 | 0.4588 (3) | 0.7648 (3) | 0.4178 (2) | 0.0263 (6) | |
H11A | 0.4767 | 0.7671 | 0.3454 | 0.032* | |
H11B | 0.5180 | 0.8285 | 0.4574 | 0.032* | |
C21 | 0.4797 (3) | 0.6278 (3) | 0.46062 (19) | 0.0225 (6) | |
C22 | 0.5133 (3) | 0.5255 (3) | 0.3993 (2) | 0.0278 (7) | |
H22 | 0.5227 | 0.5423 | 0.3294 | 0.033* | |
C23 | 0.5334 (3) | 0.3994 (3) | 0.4378 (2) | 0.0276 (7) | |
H23 | 0.5566 | 0.3302 | 0.3943 | 0.033* |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0285 (17) | 0.0339 (17) | 0.0226 (14) | 0.0009 (14) | −0.0006 (12) | 0.0006 (13) |
C2 | 0.036 (2) | 0.0424 (19) | 0.0286 (16) | −0.0085 (15) | 0.0017 (14) | −0.0003 (14) |
C3 | 0.0262 (18) | 0.066 (2) | 0.0302 (17) | −0.0075 (17) | 0.0063 (13) | −0.0001 (17) |
C4 | 0.0313 (19) | 0.053 (2) | 0.0251 (15) | 0.0132 (16) | 0.0079 (13) | 0.0026 (15) |
C4A | 0.0327 (18) | 0.0387 (18) | 0.0143 (13) | 0.0072 (14) | 0.0046 (12) | 0.0021 (12) |
C4B | 0.0414 (19) | 0.0347 (18) | 0.0150 (13) | 0.0112 (14) | 0.0048 (13) | 0.0052 (12) |
C5 | 0.054 (2) | 0.040 (2) | 0.0247 (15) | 0.0231 (18) | 0.0128 (14) | 0.0063 (14) |
C6 | 0.082 (3) | 0.031 (2) | 0.0326 (18) | 0.022 (2) | 0.0139 (18) | 0.0062 (15) |
C7 | 0.072 (3) | 0.0261 (18) | 0.0379 (18) | 0.0050 (18) | 0.0036 (18) | 0.0001 (15) |
C8 | 0.047 (2) | 0.0286 (17) | 0.0334 (17) | 0.0047 (15) | −0.0024 (14) | 0.0034 (14) |
C8A | 0.0413 (19) | 0.0222 (15) | 0.0198 (14) | 0.0052 (13) | −0.0003 (13) | 0.0022 (12) |
N9 | 0.0267 (14) | 0.0233 (13) | 0.0240 (12) | 0.0012 (11) | 0.0014 (10) | 0.0011 (10) |
C9A | 0.0260 (16) | 0.0311 (16) | 0.0166 (13) | −0.0004 (13) | −0.0002 (11) | 0.0009 (12) |
C10 | 0.0308 (17) | 0.0257 (15) | 0.0183 (13) | 0.0002 (13) | 0.0017 (12) | −0.0004 (12) |
S10 | 0.0370 (5) | 0.0305 (4) | 0.0388 (4) | −0.0045 (4) | 0.0119 (3) | 0.0054 (4) |
S11 | 0.0241 (4) | 0.0278 (4) | 0.0386 (4) | 0.0034 (3) | 0.0091 (3) | 0.0098 (3) |
C11 | 0.0215 (16) | 0.0308 (16) | 0.0270 (15) | 0.0009 (13) | 0.0053 (12) | 0.0005 (13) |
C21 | 0.0164 (15) | 0.0291 (16) | 0.0217 (13) | −0.0011 (12) | 0.0018 (11) | −0.0003 (12) |
C22 | 0.0332 (17) | 0.0314 (17) | 0.0193 (13) | 0.0032 (14) | 0.0056 (12) | −0.0001 (12) |
C23 | 0.0298 (17) | 0.0312 (17) | 0.0220 (14) | 0.0073 (13) | 0.0032 (12) | −0.0040 (12) |
C1—C2 | 1.371 (4) | C4—H4 | 0.9500 |
C2—C3 | 1.386 (4) | C5—H5 | 0.9500 |
C3—C4 | 1.364 (5) | C6—H6 | 0.9500 |
C4—C4A | 1.377 (4) | C7—H7 | 0.9500 |
C4A—C4B | 1.437 (4) | C8—H8 | 0.9500 |
C4B—C5 | 1.392 (4) | N9—C10 | 1.381 (3) |
C5—C6 | 1.353 (5) | C10—S10 | 1.630 (3) |
C6—C7 | 1.376 (5) | C10—S11 | 1.741 (3) |
C7—C8 | 1.378 (4) | S11—C11 | 1.793 (3) |
C8—C8A | 1.382 (4) | C11—C21 | 1.497 (4) |
C8A—N9 | 1.419 (3) | C11—H11A | 0.9900 |
N9—C9A | 1.422 (3) | C11—H11B | 0.9900 |
C9A—C1 | 1.384 (4) | C21—C22 | 1.377 (4) |
C4A—C9A | 1.393 (4) | C21—C23i | 1.384 (4) |
C4B—C8A | 1.389 (4) | C22—C23 | 1.375 (4) |
C1—H1 | 0.9500 | C22—H22 | 0.9500 |
C2—H2 | 0.9500 | C23—H23 | 0.9500 |
C3—H3 | 0.9500 | ||
C2—C1—C9A | 118.1 (3) | C8A—C8—H8 | 121.2 |
C2—C1—H1 | 121.0 | C8—C8A—C4B | 120.9 (3) |
C9A—C1—H1 | 121.0 | C8—C8A—N9 | 130.8 (3) |
C1—C2—C3 | 121.1 (3) | C4B—C8A—N9 | 108.3 (3) |
C1—C2—H2 | 119.4 | C10—N9—C8A | 124.8 (2) |
C3—C2—H2 | 119.4 | C10—N9—C9A | 127.6 (2) |
C4—C3—C2 | 120.7 (3) | C8A—N9—C9A | 107.6 (2) |
C4—C3—H3 | 119.6 | C1—C9A—C4A | 120.7 (3) |
C2—C3—H3 | 119.6 | C1—C9A—N9 | 130.7 (3) |
C3—C4—C4A | 119.1 (3) | C4A—C9A—N9 | 108.3 (2) |
C3—C4—H4 | 120.5 | N9—C10—S10 | 124.7 (2) |
C4A—C4—H4 | 120.5 | N9—C10—S11 | 112.99 (19) |
C4—C4A—C9A | 120.1 (3) | S10—C10—S11 | 122.32 (17) |
C4—C4A—C4B | 132.1 (3) | C10—S11—C11 | 102.82 (13) |
C9A—C4A—C4B | 107.6 (3) | C21—C11—S11 | 106.91 (19) |
C8A—C4B—C5 | 119.9 (3) | C21—C11—H11A | 110.3 |
C8A—C4B—C4A | 108.2 (3) | S11—C11—H11A | 110.3 |
C5—C4B—C4A | 131.9 (3) | C21—C11—H11B | 110.3 |
C6—C5—C4B | 118.9 (3) | S11—C11—H11B | 110.3 |
C6—C5—H5 | 120.5 | H11A—C11—H11B | 108.6 |
C4B—C5—H5 | 120.5 | C22—C21—C23i | 118.3 (3) |
C5—C6—C7 | 121.0 (3) | C22—C21—C11 | 120.4 (2) |
C5—C6—H6 | 119.5 | C23i—C21—C11 | 121.3 (2) |
C7—C6—H6 | 119.5 | C23—C22—C21 | 121.0 (2) |
C6—C7—C8 | 121.6 (3) | C23—C22—H22 | 119.5 |
C6—C7—H7 | 119.2 | C21—C22—H22 | 119.5 |
C8—C7—H7 | 119.2 | C22—C23—C21i | 120.7 (3) |
C7—C8—C8A | 117.6 (3) | C22—C23—H23 | 119.6 |
C7—C8—H8 | 121.2 | C21i—C23—H23 | 119.6 |
C9A—C1—C2—C3 | 0.6 (4) | C4B—C8A—N9—C9A | 2.0 (3) |
C1—C2—C3—C4 | 1.7 (4) | C2—C1—C9A—C4A | −3.1 (4) |
C2—C3—C4—C4A | −1.4 (4) | C2—C1—C9A—N9 | −175.8 (3) |
C3—C4—C4A—C9A | −1.0 (4) | C4—C4A—C9A—C1 | 3.4 (4) |
C3—C4—C4A—C4B | 174.3 (3) | C4B—C4A—C9A—C1 | −173.1 (2) |
C4—C4A—C4B—C8A | −175.7 (3) | C4—C4A—C9A—N9 | 177.6 (2) |
C9A—C4A—C4B—C8A | 0.1 (3) | C4B—C4A—C9A—N9 | 1.2 (3) |
C4—C4A—C4B—C5 | 2.6 (5) | C10—N9—C9A—C1 | −11.5 (4) |
C9A—C4A—C4B—C5 | 178.5 (3) | C8A—N9—C9A—C1 | 171.5 (3) |
C8A—C4B—C5—C6 | −1.7 (4) | C10—N9—C9A—C4A | 175.1 (2) |
C4A—C4B—C5—C6 | −179.9 (3) | C8A—N9—C9A—C4A | −2.0 (3) |
C4B—C5—C6—C7 | −0.6 (5) | C8A—N9—C10—S10 | −30.1 (4) |
C5—C6—C7—C8 | 2.2 (5) | C9A—N9—C10—S10 | 153.3 (2) |
C6—C7—C8—C8A | −1.4 (5) | C8A—N9—C10—S11 | 148.4 (2) |
C7—C8—C8A—C4B | −1.0 (4) | C9A—N9—C10—S11 | −28.2 (3) |
C7—C8—C8A—N9 | −177.9 (3) | N9—C10—S11—C11 | 177.53 (19) |
C5—C4B—C8A—C8 | 2.5 (4) | S10—C10—S11—C11 | −3.9 (2) |
C4A—C4B—C8A—C8 | −178.9 (2) | C10—S11—C11—C21 | −179.58 (18) |
C5—C4B—C8A—N9 | −179.9 (2) | S11—C11—C21—C22 | 117.4 (3) |
C4A—C4B—C8A—N9 | −1.3 (3) | S11—C11—C21—C23i | −63.0 (3) |
C8—C8A—N9—C10 | 2.1 (4) | C23i—C21—C22—C23 | 0.0 (5) |
C4B—C8A—N9—C10 | −175.1 (2) | C11—C21—C22—C23 | 179.6 (3) |
C8—C8A—N9—C9A | 179.3 (3) | C21—C22—C23—C21i | 0.0 (5) |
Symmetry code: (i) −x+1, −y+1, −z+1. |
D—H···A | D—H | H···A | D···A | D—H···A |
C22—H22···Cgii | 0.95 | 2.89 | 3.666 (3) | 140 |
Symmetry code: (ii) −x+1/2, y−1/2, −z+1/2. |
Experimental details
Crystal data | |
Chemical formula | C34H24N2S4 |
Mr | 588.83 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 120 |
a, b, c (Å) | 10.296 (2), 10.0793 (19), 13.137 (2) |
β (°) | 96.646 (14) |
V (Å3) | 1354.2 (4) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.38 |
Crystal size (mm) | 0.52 × 0.17 × 0.10 |
Data collection | |
Diffractometer | Bruker–Nonius KappaCCD diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 2003) |
Tmin, Tmax | 0.869, 0.963 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 15566, 2520, 1880 |
Rint | 0.062 |
(sin θ/λ)max (Å−1) | 0.606 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.052, 0.099, 1.13 |
No. of reflections | 2520 |
No. of parameters | 181 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.25, −0.30 |
Computer programs: COLLECT (Hooft, 1999), DIRAX/LSQ (Duisenberg et al., 2000), EVALCCD (Duisenberg et al., 2003), SIR2004 (Burla et al., 2005), SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).
C1—C2 | 1.371 (4) | C8A—N9 | 1.419 (3) |
C2—C3 | 1.386 (4) | N9—C9A | 1.422 (3) |
C3—C4 | 1.364 (5) | C9A—C1 | 1.384 (4) |
C4—C4A | 1.377 (4) | C4A—C9A | 1.393 (4) |
C4A—C4B | 1.437 (4) | C4B—C8A | 1.389 (4) |
C4B—C5 | 1.392 (4) | N9—C10 | 1.381 (3) |
C5—C6 | 1.353 (5) | C10—S10 | 1.630 (3) |
C6—C7 | 1.376 (5) | C10—S11 | 1.741 (3) |
C7—C8 | 1.378 (4) | S11—C11 | 1.793 (3) |
C8—C8A | 1.382 (4) | C11—C21 | 1.497 (4) |
C9A—N9—C10—S11 | −28.2 (3) | C10—S11—C11—C21 | −179.58 (18) |
N9—C10—S11—C11 | 177.53 (19) | S11—C11—C21—C22 | 117.4 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
C22—H22···Cgi | 0.95 | 2.89 | 3.666 (3) | 140 |
Symmetry code: (i) −x+1/2, y−1/2, −z+1/2. |
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Xanthate derivatives are versatile reagents for reversible addition–fragmentation chain transfer (RAFT) polymerization, capable of directing formation of a range of well controlled polymer architectures (Perrier et al., 2004; Wan et al., 2007), and we report here the structure of the title compound, (I) (Fig. 1), which was synthesized for use in such applications.
The molecules of (I) lie across inversion centres in the space group P21/n, with the reference molecule selected as that lying across (1/2, 1/2, 1/2) (Fig. 1). The carbazole unit deviates slightly from planarity, with dihedral angles between the central five-membered ring on the one hand, and, on the other hand, the outer rings containing atoms C1 and C8, respectively, of 4.9 (2) and 0.5 (2)°, while the dihedral angle between the two six-membered rings in this unit is 4.7 (2)°. This asymmetric folding may be contrasted with that observed in carbazole itself [Cambridge Structural Database (CSD; Allen, 2002) refcode CRBZOL04; Gerkin & Reppart, 1986], where the molecules lie across mirror planes in the space group Pnma, adopting a butterfly-type conformation with a dihedral angle of 2.5 (2)° between the two symmetry-related parts of the molecule. On the other hand, asymmetric folding has been reported in both N-methylcarbazole (CSD refcode NMCABZ; Popova & Chetkina, 1979) and in N-vinylcarbazole [CSD refcodes VINCBZ (Tsutsui et al., 1976) and VINCBZ01 (Tian et al., 2006)], in both of which Z' = 2. The spacer unit linking the carbazole and aryl ring systems, i.e. between atoms N9 and C21 (Fig. 1), adopts an effectively planar all-trans conformation: the maximum deviations from the mean plane through atoms N9/C10/S10/S11/C11/C21 are 0.037 (1) Å for atom S11 and 0.024 (3) Å for atom C11, to opposite sides of the mean plane. The overall molecular conformation can then be specified in terms of just two dihedral angles, those between the plane of the linker unit on the one hand, and the two ring systems on the other: for the aryl ring, this dihedral angle is 65.0 (2)°, while the corresponding value for the central ring of the carbazole unit is 29.0 (2)°.
The pattern of the bond distances in the carbazole unit (Table 1) is reminiscent of that in carbazole itself. Specifically, the bonds labelled here as C1—C2, C3—C4, C5—C6 and C7—C8 are the shortest bonds in the six-membered rings, while the bond C4A—C4B is the longest C—C bond in the carbazole unit; however, the two independent C—N bonds are longer than the corresponding bonds in carbazole. Overall the distances indicate that there is effectively no peripheral electronic delocalization. The C10—S10 bond is short for its type (Allen et al., 1987), while N9—C10 is long for its type, possibly indicative of rather little delocalization of the lone pair at N9 into the C═S double bond as a consequence of the relative orientation of the carbazole and spacer units.
The centrosymmetric molecules of (I) are linked by a combination of C—H···π(arene) hydrogen bonds and π–π stacking interactions to form a three-dimensional framework structure, whose formation is readily analysed in terms of the substructures (Ferguson et al., 1998a,b; Gregson et al., 2000) formed by the two types of interaction.
A single C—H···π(arene) hydrogen bond (Table 2) links the reference molecule directly to four other molecules: thus the reference molecule centred at (1/2, 1/2, 1/2) acts as a hydrogen-bond donor to the two molecules centred at (0, 0, 0) and (1, 1, 1) and it acts as an acceptor of hydrogen bonds from the two molecules centred at (0, 1, 0) and (1, 0, 1). In this manner, the C—H···π(arene) hydrogen bond links the molecules into a sheet lying parallel to (101) (Fig. 2). The molecules of (I) are also weakly linked into chains by a π–π stacking interaction between the carbazole units of adjacent molecules. The aryl ring containing atom C4A in the reference molecule centred at (1/2, 1/2, 1/2) makes a dihedral angle of 4.7 (2)° with the aryl ring containing atom C4B at (-x, 2-y, 1-z) and forming part of the molecule centred at (-0.5, 1.5, 1/2): the ring-centroid separation is 3.872 (2) Å, with a ring-centroid offset of ca 1.32 Å. Propagation by inversion of this interaction generates a chain of π-stacked molecules running parallel to the [110] direction (Fig. 3) and this chain links the hydrogen-bonded sheets into a three-dimensional framework. It is interesting to note that while the central aryl ring acts as a twofold donor of hydrogen bonds, it neither accepts any hydrogen bonds nor participates in any π–π stacking interactions. By contrast, the carbazole unit both accepts a hydrogen bond and participates in the π–π stacking but, despite the large number of C—H bonds present, the carbazole unit does not act as a hydrogen-bond donor.
It is thus of interest briefly to compare the molecular aggregation in compound (I) with that in carbazole. which was not discussed in the original report (Gerkin & Reppart, 1986). While there are neither N—H···π(arene) hydrogen bonds nor aromatic π–π stacking interactions present in the crystal structure of carbazole, symmetry-related pairs of C—H···π(arene) hydrogen bonds link molecules related by a 21 screw axis along [100] into a chain of rings (Bernstein et al., 1995) running parallel to the [100] direction (Fig. 4), so that the mode of supramolecular aggregation in carbazole is very different from that found in compound (I).