organic compounds
2,3-Dichloro-1,4-hydroquinone 2,3-dichloro-1,4-benzoquinone monohydrate: a quinhydrone-type 1:1 donor-acceptor [D—A] charge-transfer complex
aDepartement für Chemie und Biochemie, Universität Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
*Correspondence e-mail: liu@iac.unibe.ch
In the 6H4Cl2O2·C6H2Cl2O2·H2O, the 2,3-dichloro-1,4-hydroquinone donor (D) and the 2,3-dichloro-1,4-benzoquinone acceptor (A) molecules form alternating stacks along [100]. Their molecular planes [maximum deviations for non-H atoms: 0.0133 (14) (D) and 0.0763 (14) Å (A)] are inclined to one another by 1.45 (3)° and are thus almost parallel. There are π–π interactions involving the D and A molecules, with centroid–centroid distances of 3.5043 (9) and 3.9548 (9) Å. Intermolecular O—H⋯O hydrogen bonds involving the water molecule and the hydroxy and ketone groups lead to the formation of two-dimensional networks lying parallel to (001). These networks are linked by C—H⋯O interactions, forming a three-dimensional structure.
of the title compound (systematic name: 2,3-dichlorobenzene-1,4-diol 2,3-dichlorocyclohexa-2,5-diene-1,4-dione monohydrate), CRelated literature
For prototypical examples of similar organic redox systems, see: Yi et al. (2009a,b). For details concerning quinhydrone, a 1:1 hydroquinone-quinone adduct, and a well known molecular charge-transfer (CT) complex, see: Foster (1969). For structural studies of different polymorphs of quinhydrone, see: Matsuda et al. (1958); Sakurai (1965,1968). For details concerning quinhydrone analogues, see: Bouvet et al. (2006,2007); Patil et al. (1984); Yamamura et al. (2007). For a detailed computational study on the stacking energies and the electron density topology in quinhydrone, see: Gonzalez Moa et al. (2007).
Experimental
Crystal data
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Refinement
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Data collection: SMART (Bruker, 2003); cell SAINT (Bruker, 2003); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: Mercury (Macrae et al., 2008); software used to prepare material for publication: publCIF (Westrip, 2010).
Supporting information
10.1107/S1600536811041377/su2322sup1.cif
contains datablocks I, global. DOI:Supporting information file. DOI: 10.1107/S1600536811041377/su2322Isup2.mol
Structure factors: contains datablock I. DOI: 10.1107/S1600536811041377/su2322Isup3.hkl
Supporting information file. DOI: 10.1107/S1600536811041377/su2322Isup4.cml
Deep-red coloured, elongated (up to 5 mm long) plate-shaped crystals of the 1:1 donor-acceptor adduct [D—A].H2O (D = 2,3-Dichloro-1,4-hydroquinone; A = 2,3-Dichloro-1,4-benzoquinone) were formed by slow
of the single component (A) within a closed flask at room-temperature under aerobic conditions.H atoms of the water molecule were located in a difference Fourier map and refined with Uiso(H) = 1.5 times Ueq(O). Other H atoms were positioned geometrically and refined using a riding model (including
about the hydroxy C—O bond): O—H = 0.84 Å, C—H = 0.95 Å, with Uiso(H) = k × Ueq(O,C), where k = 1.5 for OH H atoms, and k = 1.2 for all other H atoms.Data collection: SMART (Bruker, 2003); cell
SAINT (Bruker, 2003); data reduction: SAINT (Bruker, 2003); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: Mercury (Macrae et al., 2008); software used to prepare material for publication: publCIF (Westrip, 2010).Fig. 1. The molecular structure of the title compound, with atom labels and displacement ellipsoids drawn at the 50% probability level [left donor (D); right acceptor (A)]. | |
Fig. 2. A view perpendicular to the molecular planes, of the stacking of the acceptor (A) and donor (D) molecules in the title compound. | |
Fig. 3. The crystal packing of the title compound, viewed along the a axis. Stacks of donor (D) and acceptor (A) molecules are connected by O-H···O hydrogen bonds (dashed blue lines). |
C6H4Cl2O2·C6H2Cl2O2·H2O | F(000) = 752 |
Mr = 373.98 | Dx = 1.771 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 7958 reflections |
a = 7.15329 (14) Å | θ = 2.8–27.5° |
b = 7.19541 (15) Å | µ = 0.86 mm−1 |
c = 27.2811 (5) Å | T = 173 K |
β = 92.9738 (18)° | Plate, red |
V = 1402.29 (5) Å3 | 0.3 × 0.2 × 0.07 mm |
Z = 4 |
Siemens SMART 1K CCD area-detector diffractometer | 3138 independent reflections |
Radiation source: fine-focus sealed tube | 2653 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.026 |
rotation method scans | θmax = 27.9°, θmin = 2.9° |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | h = −8→9 |
Tmin = 0.859, Tmax = 0.942 | k = −9→9 |
19255 measured reflections | l = −35→35 |
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)] = 0.031 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.077 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.04 | w = 1/[σ2(Fo2) + (0.0429P)2 + 0.583P] where P = (Fo2 + 2Fc2)/3 |
3138 reflections | (Δ/σ)max = 0.001 |
198 parameters | Δρmax = 0.49 e Å−3 |
0 restraints | Δρmin = −0.19 e Å−3 |
C6H4Cl2O2·C6H2Cl2O2·H2O | V = 1402.29 (5) Å3 |
Mr = 373.98 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 7.15329 (14) Å | µ = 0.86 mm−1 |
b = 7.19541 (15) Å | T = 173 K |
c = 27.2811 (5) Å | 0.3 × 0.2 × 0.07 mm |
β = 92.9738 (18)° |
Siemens SMART 1K CCD area-detector diffractometer | 3138 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 2653 reflections with I > 2σ(I) |
Tmin = 0.859, Tmax = 0.942 | Rint = 0.026 |
19255 measured reflections |
R[F2 > 2σ(F2)] = 0.031 | 0 restraints |
wR(F2) = 0.077 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.04 | Δρmax = 0.49 e Å−3 |
3138 reflections | Δρmin = −0.19 e Å−3 |
198 parameters |
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 | ||
C1 | 0.7866 (2) | 0.9165 (2) | 0.38598 (7) | 0.0220 (4) | |
O1 | 0.72734 (19) | 1.07053 (18) | 0.37504 (5) | 0.0299 (3) | |
C2 | 0.8432 (2) | 0.7822 (3) | 0.34779 (6) | 0.0216 (4) | |
Cl2 | 0.81893 (7) | 0.85660 (7) | 0.288391 (16) | 0.03021 (13) | |
C3 | 0.9107 (2) | 0.6140 (3) | 0.36016 (6) | 0.0220 (4) | |
Cl3 | 0.97542 (7) | 0.45526 (7) | 0.317735 (18) | 0.03252 (13) | |
C4 | 0.9362 (2) | 0.5565 (2) | 0.41269 (7) | 0.0229 (4) | |
O4 | 1.00840 (19) | 0.40868 (18) | 0.42426 (5) | 0.0305 (3) | |
C5 | 0.8731 (2) | 0.6879 (3) | 0.44963 (7) | 0.0252 (4) | |
H5 | 0.8808 | 0.6525 | 0.4832 | 0.030* | |
C6 | 0.8052 (3) | 0.8555 (3) | 0.43743 (7) | 0.0251 (4) | |
H6 | 0.7682 | 0.9370 | 0.4625 | 0.030* | |
C11 | 0.3767 (2) | 0.7229 (2) | 0.33596 (6) | 0.0194 (3) | |
O11 | 0.43186 (18) | 0.60154 (17) | 0.30131 (4) | 0.0245 (3) | |
H11 | 0.4304 | 0.6550 | 0.2739 | 0.037* | |
C12 | 0.3915 (2) | 0.6700 (2) | 0.38514 (6) | 0.0185 (3) | |
Cl12 | 0.47890 (6) | 0.45165 (6) | 0.399712 (15) | 0.02360 (11) | |
C13 | 0.3366 (2) | 0.7902 (2) | 0.42204 (6) | 0.0196 (3) | |
Cl13 | 0.35592 (7) | 0.72408 (6) | 0.482946 (16) | 0.02805 (12) | |
C14 | 0.2652 (2) | 0.9655 (2) | 0.40960 (6) | 0.0206 (4) | |
O14 | 0.2109 (2) | 1.07750 (18) | 0.44656 (5) | 0.0289 (3) | |
H14 | 0.1681 | 1.1775 | 0.4347 | 0.043* | |
C15 | 0.2513 (2) | 1.0172 (2) | 0.36060 (6) | 0.0220 (4) | |
H15 | 0.2035 | 1.1366 | 0.3519 | 0.026* | |
C16 | 0.3058 (2) | 0.8979 (2) | 0.32418 (6) | 0.0213 (4) | |
H16 | 0.2947 | 0.9361 | 0.2908 | 0.026* | |
O20 | 0.4387 (2) | 0.7413 (2) | 0.21375 (5) | 0.0325 (3) | |
H20A | 0.393 (3) | 0.691 (4) | 0.1903 (10) | 0.049* | |
H20B | 0.472 (4) | 0.834 (4) | 0.2061 (10) | 0.049* |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0203 (8) | 0.0230 (9) | 0.0224 (9) | −0.0010 (7) | −0.0011 (7) | 0.0017 (7) |
O1 | 0.0371 (7) | 0.0239 (7) | 0.0283 (7) | 0.0054 (6) | −0.0032 (6) | 0.0030 (5) |
C2 | 0.0203 (8) | 0.0282 (9) | 0.0160 (8) | −0.0027 (7) | −0.0002 (7) | 0.0021 (7) |
Cl2 | 0.0329 (2) | 0.0399 (3) | 0.0178 (2) | 0.0027 (2) | 0.00070 (17) | 0.00536 (19) |
C3 | 0.0190 (8) | 0.0246 (9) | 0.0226 (9) | −0.0017 (7) | 0.0023 (7) | −0.0043 (7) |
Cl3 | 0.0360 (3) | 0.0321 (3) | 0.0298 (3) | 0.0031 (2) | 0.00496 (19) | −0.00926 (19) |
C4 | 0.0195 (8) | 0.0235 (9) | 0.0254 (9) | −0.0020 (7) | −0.0005 (7) | 0.0027 (7) |
O4 | 0.0315 (7) | 0.0243 (7) | 0.0356 (8) | 0.0055 (6) | −0.0008 (6) | 0.0056 (6) |
C5 | 0.0266 (9) | 0.0297 (9) | 0.0193 (9) | 0.0005 (8) | 0.0012 (7) | 0.0028 (7) |
C6 | 0.0267 (9) | 0.0281 (9) | 0.0206 (9) | 0.0021 (8) | 0.0022 (7) | −0.0022 (7) |
C11 | 0.0206 (8) | 0.0185 (8) | 0.0190 (8) | −0.0021 (7) | 0.0013 (6) | −0.0019 (6) |
O11 | 0.0373 (7) | 0.0196 (6) | 0.0169 (6) | 0.0037 (5) | 0.0047 (5) | 0.0002 (5) |
C12 | 0.0188 (8) | 0.0144 (7) | 0.0223 (9) | 0.0003 (6) | −0.0001 (6) | 0.0023 (6) |
Cl12 | 0.0305 (2) | 0.0166 (2) | 0.0236 (2) | 0.00314 (17) | 0.00040 (17) | 0.00279 (16) |
C13 | 0.0214 (8) | 0.0210 (8) | 0.0163 (8) | −0.0018 (7) | 0.0002 (6) | 0.0022 (7) |
Cl13 | 0.0374 (3) | 0.0288 (2) | 0.0179 (2) | 0.0034 (2) | 0.00093 (17) | 0.00261 (17) |
C14 | 0.0219 (8) | 0.0178 (8) | 0.0221 (9) | −0.0007 (7) | 0.0021 (7) | −0.0025 (7) |
O14 | 0.0412 (8) | 0.0213 (6) | 0.0245 (7) | 0.0081 (6) | 0.0043 (6) | −0.0023 (5) |
C15 | 0.0241 (9) | 0.0161 (8) | 0.0257 (9) | 0.0005 (7) | −0.0009 (7) | 0.0034 (7) |
C16 | 0.0232 (9) | 0.0220 (8) | 0.0186 (9) | −0.0001 (7) | 0.0004 (7) | 0.0041 (7) |
O20 | 0.0539 (9) | 0.0238 (7) | 0.0192 (7) | −0.0103 (7) | −0.0027 (6) | 0.0009 (5) |
C1—O1 | 1.218 (2) | C11—C12 | 1.393 (2) |
C1—C6 | 1.470 (3) | O11—H11 | 0.8400 |
C1—C2 | 1.493 (2) | C12—C13 | 1.400 (2) |
C2—C3 | 1.340 (3) | C12—Cl12 | 1.7292 (16) |
C2—Cl2 | 1.7070 (17) | C13—C14 | 1.396 (2) |
C3—C4 | 1.494 (2) | C13—Cl13 | 1.7270 (17) |
C3—Cl3 | 1.7069 (18) | C14—O14 | 1.363 (2) |
C4—O4 | 1.217 (2) | C14—C15 | 1.386 (2) |
C4—C5 | 1.470 (3) | O14—H14 | 0.8400 |
C5—C6 | 1.335 (3) | C15—C16 | 1.384 (2) |
C5—H5 | 0.9500 | C15—H15 | 0.9500 |
C6—H6 | 0.9500 | C16—H16 | 0.9500 |
C11—O11 | 1.360 (2) | O20—H20A | 0.79 (3) |
C11—C16 | 1.389 (2) | O20—H20B | 0.74 (3) |
O1—C1—C6 | 121.26 (17) | C16—C11—C12 | 118.64 (16) |
O1—C1—C2 | 121.44 (16) | C11—O11—H11 | 109.5 |
C6—C1—C2 | 117.30 (15) | C11—C12—C13 | 120.89 (15) |
C3—C2—C1 | 121.09 (15) | C11—C12—Cl12 | 118.58 (13) |
C3—C2—Cl2 | 122.70 (14) | C13—C12—Cl12 | 120.53 (13) |
C1—C2—Cl2 | 116.21 (13) | C14—C13—C12 | 119.78 (15) |
C2—C3—C4 | 121.08 (16) | C14—C13—Cl13 | 119.55 (13) |
C2—C3—Cl3 | 122.71 (14) | C12—C13—Cl13 | 120.68 (13) |
C4—C3—Cl3 | 116.20 (13) | O14—C14—C15 | 123.05 (15) |
O4—C4—C5 | 121.72 (17) | O14—C14—C13 | 117.98 (15) |
O4—C4—C3 | 121.32 (17) | C15—C14—C13 | 118.96 (16) |
C5—C4—C3 | 116.95 (15) | C14—O14—H14 | 109.5 |
C6—C5—C4 | 122.04 (16) | C16—C15—C14 | 121.10 (16) |
C6—C5—H5 | 119.0 | C16—C15—H15 | 119.4 |
C4—C5—H5 | 119.0 | C14—C15—H15 | 119.4 |
C5—C6—C1 | 121.43 (17) | C15—C16—C11 | 120.63 (16) |
C5—C6—H6 | 119.3 | C15—C16—H16 | 119.7 |
C1—C6—H6 | 119.3 | C11—C16—H16 | 119.7 |
O11—C11—C16 | 122.47 (15) | H20A—O20—H20B | 108 (3) |
O11—C11—C12 | 118.89 (15) | ||
O1—C1—C2—C3 | 179.07 (17) | O11—C11—C12—C13 | 179.97 (15) |
C6—C1—C2—C3 | −0.9 (2) | C16—C11—C12—C13 | −0.1 (3) |
O1—C1—C2—Cl2 | −0.3 (2) | O11—C11—C12—Cl12 | −0.2 (2) |
C6—C1—C2—Cl2 | 179.69 (13) | C16—C11—C12—Cl12 | 179.74 (13) |
C1—C2—C3—C4 | −1.5 (3) | C11—C12—C13—C14 | 0.2 (3) |
Cl2—C2—C3—C4 | 177.83 (13) | Cl12—C12—C13—C14 | −179.57 (13) |
C1—C2—C3—Cl3 | 179.46 (13) | C11—C12—C13—Cl13 | −179.82 (13) |
Cl2—C2—C3—Cl3 | −1.2 (2) | Cl12—C12—C13—Cl13 | 0.4 (2) |
C2—C3—C4—O4 | −175.28 (17) | C12—C13—C14—O14 | 179.13 (15) |
Cl3—C3—C4—O4 | 3.8 (2) | Cl13—C13—C14—O14 | −0.8 (2) |
C2—C3—C4—C5 | 3.7 (2) | C12—C13—C14—C15 | −0.4 (3) |
Cl3—C3—C4—C5 | −177.23 (13) | Cl13—C13—C14—C15 | 179.68 (13) |
O4—C4—C5—C6 | 175.42 (18) | O14—C14—C15—C16 | −179.12 (16) |
C3—C4—C5—C6 | −3.5 (3) | C13—C14—C15—C16 | 0.4 (3) |
C4—C5—C6—C1 | 1.2 (3) | C14—C15—C16—C11 | −0.2 (3) |
O1—C1—C6—C5 | −178.88 (17) | O11—C11—C16—C15 | 180.00 (16) |
C2—C1—C6—C5 | 1.1 (3) | C12—C11—C16—C15 | 0.0 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
O11—H11···O20 | 0.84 | 1.76 | 2.5947 (18) | 173 |
O14—H14···O4i | 0.84 | 2.03 | 2.8381 (18) | 161 |
O20—H20A···O1ii | 0.79 (3) | 2.12 (3) | 2.914 (2) | 177 (3) |
O20—H20B···O11iii | 0.74 (3) | 2.06 (3) | 2.7899 (19) | 169 (3) |
C6—H6···O14iv | 0.95 | 2.48 | 3.209 (2) | 134 |
Symmetry codes: (i) x−1, y+1, z; (ii) −x+1, y−1/2, −z+1/2; (iii) −x+1, y+1/2, −z+1/2; (iv) −x+1, −y+2, −z+1. |
Experimental details
Crystal data | |
Chemical formula | C6H4Cl2O2·C6H2Cl2O2·H2O |
Mr | 373.98 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 173 |
a, b, c (Å) | 7.15329 (14), 7.19541 (15), 27.2811 (5) |
β (°) | 92.9738 (18) |
V (Å3) | 1402.29 (5) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.86 |
Crystal size (mm) | 0.3 × 0.2 × 0.07 |
Data collection | |
Diffractometer | Siemens SMART 1K CCD area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.859, 0.942 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 19255, 3138, 2653 |
Rint | 0.026 |
(sin θ/λ)max (Å−1) | 0.658 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.031, 0.077, 1.04 |
No. of reflections | 3138 |
No. of parameters | 198 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.49, −0.19 |
Computer programs: SMART (Bruker, 2003), SAINT (Bruker, 2003), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), Mercury (Macrae et al., 2008), publCIF (Westrip, 2010).
D—H···A | D—H | H···A | D···A | D—H···A |
O11—H11···O20 | 0.84 | 1.76 | 2.5947 (18) | 173 |
O14—H14···O4i | 0.84 | 2.03 | 2.8381 (18) | 161 |
O20—H20A···O1ii | 0.79 (3) | 2.12 (3) | 2.914 (2) | 177 (3) |
O20—H20B···O11iii | 0.74 (3) | 2.06 (3) | 2.7899 (19) | 169 (3) |
C6—H6···O14iv | 0.95 | 2.48 | 3.209 (2) | 134 |
Symmetry codes: (i) x−1, y+1, z; (ii) −x+1, y−1/2, −z+1/2; (iii) −x+1, y+1/2, −z+1/2; (iv) −x+1, −y+2, −z+1. |
Acknowledgements
The X-ray
was possible thanks to the Swiss National Science Foundation (R'Equip project 206021–128724).References
Bouvet, M., Malézieux, B. & Herson, P. (2006). Chem. Commun. pp. 1751–1753. Web of Science CSD CrossRef Google Scholar
Bouvet, M., Malézieux, B., Herson, P. & Villain, F. (2007). CrystEngComm, 9, 270–272. Web of Science CSD CrossRef CAS Google Scholar
Bruker (2003). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Foster, F. (1969). In Organic Charge-Transfer Complexes. Academic Press: New York. Google Scholar
Gonzalez Moa, M. J., Mandado, M. & Mosquera, R. A. (2007). J. Phys. Chem. A, 111, 1998–2001. PubMed Google Scholar
Macrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466–470. Web of Science CrossRef CAS IUCr Journals Google Scholar
Matsuda, H., Osaki, K. & Nitta, I. (1958). Bull. Chem. Soc. Jpn, 31, 611–620. CrossRef CAS Web of Science Google Scholar
Patil, A. O., Curtin, D. Y. & Paul, I. C. (1984). J. Am. Chem. Soc. 106, 4010–4015. CSD CrossRef CAS Web of Science Google Scholar
Sakurai, T. (1965). Acta Cryst. 19, 320–330. CSD CrossRef CAS IUCr Journals Web of Science Google Scholar
Sakurai, T. (1968). Acta Cryst. B24, 403–412. CSD CrossRef CAS IUCr Journals Web of Science Google Scholar
Sheldrick, G. M. (1996). SADABS. University of Göttingen, Germany. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Westrip, S. P. (2010). J. Appl. Cryst. 43, 920–925. Web of Science CrossRef CAS IUCr Journals Google Scholar
Yamamura, K., Yamane, J., Eda, K., Tajima, F., Yamada, Y. & Hashimoto, M. (2007). J. Mol. Struct. 842, 12–16. Web of Science CSD CrossRef CAS Google Scholar
Yi, C., Blum, C., Liu, S.-X., Keene, T. D., Frei, G., Neels, A. & Decurtins, S. (2009a). Org. Lett. 11, 2261–2264. Web of Science CSD CrossRef PubMed CAS Google Scholar
Yi, C., Liu, S.-X., Neels, A., Renaud, P. & Decurtins, S. (2009b). Org. Lett. 11, 5530–5533. Web of Science CSD CrossRef PubMed CAS Google Scholar
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Quinones as electron acceptors (A) and their reduced forms, semiquinones and dihydroquinones as electron donors (D) represent prototypical examples of organice redox systems (Yi et al., 2009a,b). Furthermore, it is certainly true that interactions between aromatic π-systems have long been observed in crystal structures and rationales for the occurrence of π-π interactions have included explanations which are based on electron donor-acceptor [D—A] models. Such charge-transfer (CT) complexes may form when good electron donors and acceptors lie in close proximity, and this situation is typically associated with intense electronic CT transitions in the UV-vis spectral region. Basically, the filled donor molecular orbital (HOMO) and the vacant acceptor molecular orbital (LUMO) maximize their overlap. Quinhydrone, a 1:1 hydroquinone-quinone adduct, is a well known molecular CT complex (Foster, 1969) and its complex stabilization is based on the CT between the electron donor (hydroquinone) and the electron acceptor (quinone). Structural studies of different polymorphs of quinhydrone have been undertaken (Matsuda et al., 1958; Sakurai, 1965, 1968). Quinhydrone analogues have also been studied (Bouvet et al., 2006, 2007, Patil et al., 1984 and Yamamura et al., 2007). A detailed computational study on the stacking energies and the electron density topology in quinhydrone has recently been given (Gonzalez Moa et al., 2007). Additionally, hydrogen bonds contribute further stability, both in the solid state as well as in solution. We report herein on the crystal structure of the title quinhydrone analogue.
The molecular structure of the title compound is illustrated in Fig. 1. The 2,3-Dichloro-1,4-hydroquinone donor (D) and the 2,3-Dichloro-1,4-benzoquinone acceptor (A) molecules form alternate stacks along the [100] direction with their molecular planes [max. deviations for non-H atoms: (D) = 0.0133 (14)Å and (A) = 0.0763 (14)Å ] are tilted by ca. 22.8° and 23.1° about the [100] direction. Their molecular planes are inclined to one another by 1.45 (3)° and are thus almost parallel (Fig. 2). The π–π interactions involving the six-membered rings of the (D) [C11-C16] and (A) [C1-C6] molecules have centroid-centroid distances of 3.5043 (9) Å [D···Ai; symmetry code (i) x-1, y, z] and 3.9548 (9)Å [D···A].
Intermolecular O—H···O hydrogen bonds between water and the hydroxyl and ketone groups of adjacent stacks form a complex two-dimensional network lying parallel to (001) [Fig. 3]. Chlorine atoms, Cl2 and Cl3i, of (A) in adjacent stacks are in short contact with a distance of 3.3902 (7) Å [symmetry code: (i) = 2-x, 0.5+y, 0.5-z]. The two-dimensional networks are linked via C-H···O contacts to form a three-dimensional structure.