In the 2:1 cocrystal of quinoxaline with hydroquinone, 2C
8H
6N
2·C
6H
6O
2, the phenolic molecule is located on an inversion centre. It is connected
via O—H
N interactions to two molecules of the heterobase, forming discrete hydrogen-bonded assemblies. Quinoxaline molecules are arranged into stacks by π–π face-to-face interactions whereas the hydroquinone molecules occupy channels formed between these stacks.
Supporting information
CCDC reference: 618177
Key indicators
- Single-crystal X-ray study
- T = 100 K
- Mean (C-C) = 0.002 Å
- R factor = 0.045
- wR factor = 0.112
- Data-to-parameter ratio = 12.4
checkCIF/PLATON results
No syntax errors found
Alert level C
PLAT041_ALERT_1_C Calc. and Rep. SumFormula Strings Differ .... ?
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ .... ?
PLAT045_ALERT_1_C Calculated and Reported Z Differ by ............ 2.00 Ratio
PLAT720_ALERT_4_C Number of Unusual/Non-Standard Label(s) ........ 6
0 ALERT level A = In general: serious problem
0 ALERT level B = Potentially serious problem
4 ALERT level C = Check and explain
0 ALERT level G = General alerts; check
3 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
0 ALERT type 2 Indicator that the structure model may be wrong or deficient
0 ALERT type 3 Indicator that the structure quality may be low
1 ALERT type 4 Improvement, methodology, query or suggestion
0 ALERT type 5 Informative message, check
Data collection: CrysAlis CCD (Oxford Diffraction, 2004); cell refinement: CrysAlis CCD; data reduction: CrysAlis RED (Oxford Diffraction, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: Stereochemical Workstation Operation Manual (Siemens, 1989) and
Mercury (Version 1.4; Bruno et al., 2002); software used to prepare material for publication: SHELXL97.
quinoxaline–benzene-1,4-diol (2/1)
top
Crystal data top
2C8H6N2·C6H6O2 | Z = 1 |
Mr = 370.40 | F(000) = 194 |
Triclinic, P1 | Dx = 1.385 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 7.0724 (9) Å | Cell parameters from 1855 reflections |
b = 7.2096 (10) Å | θ = 4–25° |
c = 9.1803 (12) Å | µ = 0.09 mm−1 |
α = 72.204 (12)° | T = 100 K |
β = 88.516 (11)° | Plate, colourless |
γ = 85.046 (11)° | 0.40 × 0.40 × 0.15 mm |
V = 444.03 (10) Å3 | |
Data collection top
Kuma KM-4-CCD κ-geometry diffractometer | 1258 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.043 |
Graphite monochromator | θmax = 25.0°, θmin = 2.3° |
ω scans | h = −8→5 |
3360 measured reflections | k = −8→8 |
1573 independent reflections | l = −10→10 |
Refinement top
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)] = 0.045 | Hydrogen site location: difference Fourier map |
wR(F2) = 0.112 | H-atom parameters constrained |
S = 1.09 | w = 1/[σ2(Fo2) + (0.0598P)2 + 0.0086P] where P = (Fo2 + 2Fc2)/3 |
1573 reflections | (Δ/σ)max < 0.001 |
127 parameters | Δρmax = 0.16 e Å−3 |
0 restraints | Δρmin = −0.25 e Å−3 |
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 | x | y | z | Uiso*/Ueq | |
O1 | 0.21133 (16) | 0.81756 (16) | 0.87081 (13) | 0.0198 (3) | |
H1O | 0.2923 | 0.7882 | 0.8097 | 0.024* | |
C1 | 0.1082 (2) | 0.6586 (2) | 0.93286 (19) | 0.0162 (4) | |
C2 | 0.1304 (2) | 0.4913 (2) | 0.88608 (19) | 0.0167 (4) | |
H2 | 0.2167 | 0.4849 | 0.8050 | 0.020* | |
C3 | 0.0237 (2) | 0.3337 (2) | 0.95312 (19) | 0.0177 (4) | |
H3 | 0.0411 | 0.2205 | 0.9185 | 0.021* | |
N1A | 0.48166 (18) | 0.72676 (19) | 0.66305 (15) | 0.0177 (4) | |
C2A | 0.6570 (2) | 0.6492 (2) | 0.6950 (2) | 0.0192 (4) | |
H2AA | 0.6990 | 0.6101 | 0.7982 | 0.023* | |
C3A | 0.7858 (2) | 0.6221 (2) | 0.58003 (19) | 0.0193 (4) | |
H3AA | 0.9092 | 0.5616 | 0.6105 | 0.023* | |
N4A | 0.74228 (19) | 0.6766 (2) | 0.43385 (16) | 0.0194 (4) | |
C5A | 0.5012 (2) | 0.8216 (2) | 0.24289 (19) | 0.0189 (4) | |
H5AA | 0.5889 | 0.8118 | 0.1649 | 0.023* | |
C6A | 0.3179 (2) | 0.8960 (2) | 0.2051 (2) | 0.0202 (4) | |
H6AA | 0.2792 | 0.9373 | 0.1010 | 0.024* | |
C7A | 0.1860 (2) | 0.9118 (2) | 0.3200 (2) | 0.0205 (4) | |
H7AA | 0.0586 | 0.9608 | 0.2926 | 0.025* | |
C8A | 0.2400 (2) | 0.8574 (2) | 0.4702 (2) | 0.0185 (4) | |
H8AA | 0.1512 | 0.8714 | 0.5464 | 0.022* | |
C9A | 0.4283 (2) | 0.7801 (2) | 0.51173 (19) | 0.0158 (4) | |
C10A | 0.5600 (2) | 0.7595 (2) | 0.3973 (2) | 0.0166 (4) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O1 | 0.0206 (6) | 0.0202 (7) | 0.0199 (7) | −0.0029 (5) | 0.0064 (5) | −0.0082 (5) |
C1 | 0.0141 (8) | 0.0176 (9) | 0.0154 (9) | −0.0004 (7) | −0.0026 (7) | −0.0028 (7) |
C2 | 0.0146 (8) | 0.0218 (9) | 0.0137 (9) | 0.0025 (7) | 0.0011 (7) | −0.0065 (7) |
C3 | 0.0184 (9) | 0.0181 (9) | 0.0179 (9) | 0.0014 (7) | −0.0012 (7) | −0.0084 (7) |
N1A | 0.0189 (8) | 0.0168 (7) | 0.0181 (8) | −0.0043 (6) | 0.0017 (6) | −0.0057 (6) |
C2A | 0.0219 (9) | 0.0167 (9) | 0.0187 (10) | −0.0031 (7) | −0.0018 (7) | −0.0043 (7) |
C3A | 0.0164 (9) | 0.0198 (9) | 0.0223 (10) | −0.0009 (7) | −0.0013 (7) | −0.0075 (8) |
N4A | 0.0178 (8) | 0.0190 (7) | 0.0223 (8) | −0.0009 (6) | 0.0018 (6) | −0.0077 (6) |
C5A | 0.0220 (9) | 0.0174 (9) | 0.0189 (10) | −0.0015 (7) | 0.0043 (7) | −0.0083 (7) |
C6A | 0.0248 (9) | 0.0182 (9) | 0.0174 (9) | −0.0022 (7) | −0.0022 (7) | −0.0049 (7) |
C7A | 0.0166 (9) | 0.0168 (9) | 0.0269 (10) | 0.0010 (7) | −0.0026 (7) | −0.0051 (8) |
C8A | 0.0177 (9) | 0.0162 (8) | 0.0236 (10) | −0.0019 (7) | 0.0052 (7) | −0.0094 (7) |
C9A | 0.0188 (9) | 0.0107 (8) | 0.0185 (9) | −0.0039 (7) | 0.0020 (7) | −0.0047 (7) |
C10A | 0.0170 (9) | 0.0119 (8) | 0.0216 (9) | −0.0021 (7) | 0.0017 (7) | −0.0061 (7) |
Geometric parameters (Å, º) top
O1—C1 | 1.3761 (19) | C3A—H3AA | 0.9500 |
O1—H1O | 0.8500 | N4A—C10A | 1.378 (2) |
C1—C2 | 1.394 (2) | C5A—C6A | 1.370 (2) |
C1—C3i | 1.395 (2) | C5A—C10A | 1.412 (2) |
C2—C3 | 1.392 (2) | C5A—H5AA | 0.9500 |
C2—H2 | 0.9600 | C6A—C7A | 1.415 (3) |
C3—C1i | 1.395 (2) | C6A—H6AA | 0.9500 |
C3—H3 | 0.9599 | C7A—C8A | 1.368 (2) |
N1A—C2A | 1.318 (2) | C7A—H7AA | 0.9500 |
N1A—C9A | 1.377 (2) | C8A—C9A | 1.414 (2) |
C2A—C3A | 1.423 (2) | C8A—H8AA | 0.9500 |
C2A—H2AA | 0.9500 | C9A—C10A | 1.419 (2) |
C3A—N4A | 1.315 (2) | | |
| | | |
C1—O1—H1O | 107.9 | C6A—C5A—C10A | 120.21 (16) |
O1—C1—C2 | 122.61 (15) | C6A—C5A—H5AA | 119.9 |
O1—C1—C3i | 118.35 (15) | C10A—C5A—H5AA | 119.9 |
C2—C1—C3i | 119.04 (15) | C5A—C6A—C7A | 120.47 (16) |
C3—C2—C1 | 120.48 (15) | C5A—C6A—H6AA | 119.8 |
C3—C2—H2 | 119.0 | C7A—C6A—H6AA | 119.8 |
C1—C2—H2 | 120.5 | C8A—C7A—C6A | 120.68 (15) |
C2—C3—C1i | 120.48 (16) | C8A—C7A—H7AA | 119.7 |
C2—C3—H3 | 118.9 | C6A—C7A—H7AA | 119.7 |
C1i—C3—H3 | 120.6 | C7A—C8A—C9A | 119.77 (16) |
C2A—N1A—C9A | 116.38 (14) | C7A—C8A—H8AA | 120.1 |
N1A—C2A—C3A | 122.24 (15) | C9A—C8A—H8AA | 120.1 |
N1A—C2A—H2AA | 118.9 | N1A—C9A—C8A | 119.35 (15) |
C3A—C2A—H2AA | 118.9 | N1A—C9A—C10A | 120.88 (14) |
N4A—C3A—C2A | 123.23 (15) | C8A—C9A—C10A | 119.77 (15) |
N4A—C3A—H3AA | 118.4 | N4A—C10A—C5A | 119.37 (15) |
C2A—C3A—H3AA | 118.4 | N4A—C10A—C9A | 121.54 (15) |
C3A—N4A—C10A | 115.63 (15) | C5A—C10A—C9A | 119.07 (15) |
Symmetry code: (i) −x, −y+1, −z+2. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1O···N1A | 0.85 | 1.99 | 2.8425 (18) | 179 |
C7A—H7AA···O1ii | 0.95 | 2.57 | 3.463 (2) | 157 |
C6A—H6AA···O1iii | 0.95 | 2.58 | 3.400 (2) | 144 |
Symmetry codes: (ii) −x, −y+2, −z+1; (iii) x, y, z−1. |