Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270101011647/gd1161sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270101011647/gd1161Isup2.hkl |
CCDC reference: 174837
4,4'-Bipyridine (156 mg, 1 mmol) and tetrahydroxybenzoquinone dihydrate (156 mg, 1 mmol) were dissolved in methanol and water producing a deep-red solution. Crystals suitable for X-ray structure determination were obtained by slow evaporation of the solvent at room temperature.
All H atoms were found in the difference Fourier maps and were refined with isotropic displacement parameters fixed to their parent atoms; the C–H and O–H distances all refined to within standard ranges.
Data collection: SMART (Bruker, 1998); cell refinement: SMART; data reduction: SAINT (Bruker, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997).
3C10H8N2·2C6H4O6 | Z = 1 |
Mr = 812.74 | F(000) = 422 |
Triclinic, P1 | Dx = 1.492 Mg m−3 |
a = 8.8856 (8) Å | Mo Kα radiation, λ = 0.71073 Å |
b = 9.0728 (9) Å | Cell parameters from 910 reflections |
c = 12.9288 (11) Å | θ = 9.3–22.1° |
α = 109.164 (5)° | µ = 0.11 mm−1 |
β = 92.476 (5)° | T = 100 K |
γ = 111.074 (5)° | Irregular, brown |
V = 903.17 (14) Å3 | 0.6 × 0.4 × 0.3 mm |
Bruker SMART CCD diffractometer | 4127 independent reflections |
Radiation source: fine-focus sealed tube | 2628 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.037 |
ω scans | θmax = 27.5°, θmin = 1.7° |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | h = −10→11 |
Tmin = 0.754, Tmax = 1.000 | k = −11→11 |
9859 measured reflections | l = −16→16 |
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)] = 0.038 | Hydrogen site location: difference Fourier map |
wR(F2) = 0.067 | Only H-atom coordinates refined |
S = 1.07 | w = 1/[σ2(Fo2) + (0.02P)2] where P = (Fo2 + 2Fc2)/3 |
4127 reflections | (Δ/σ)max < 0.001 |
319 parameters | Δρmax = 0.27 e Å−3 |
0 restraints | Δρmin = −0.25 e Å−3 |
3C10H8N2·2C6H4O6 | γ = 111.074 (5)° |
Mr = 812.74 | V = 903.17 (14) Å3 |
Triclinic, P1 | Z = 1 |
a = 8.8856 (8) Å | Mo Kα radiation |
b = 9.0728 (9) Å | µ = 0.11 mm−1 |
c = 12.9288 (11) Å | T = 100 K |
α = 109.164 (5)° | 0.6 × 0.4 × 0.3 mm |
β = 92.476 (5)° |
Bruker SMART CCD diffractometer | 4127 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 2628 reflections with I > 2σ(I) |
Tmin = 0.754, Tmax = 1.000 | Rint = 0.037 |
9859 measured reflections |
R[F2 > 2σ(F2)] = 0.038 | 0 restraints |
wR(F2) = 0.067 | Only H-atom coordinates refined |
S = 1.07 | Δρmax = 0.27 e Å−3 |
4127 reflections | Δρmin = −0.25 e Å−3 |
319 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
C1 | 0.89557 (18) | 0.82743 (19) | 0.47812 (12) | 0.0173 (3) | |
O1 | 0.80029 (12) | 0.68015 (13) | 0.46000 (8) | 0.0227 (3) | |
C2 | 0.86208 (18) | 0.92017 (19) | 0.41054 (12) | 0.0176 (3) | |
O2 | 0.72974 (13) | 0.83418 (14) | 0.32649 (9) | 0.0249 (3) | |
H2 | 0.6954 (19) | 0.728 (2) | 0.3104 (13) | 0.030* | |
C3 | 0.95777 (18) | 1.08520 (19) | 0.43304 (12) | 0.0179 (3) | |
O3 | 0.92496 (13) | 1.16916 (13) | 0.37192 (9) | 0.0236 (3) | |
H3 | 1.0132 (18) | 1.278 (2) | 0.3861 (12) | 0.028* | |
C4 | 0.66918 (18) | 0.56848 (18) | 0.04832 (12) | 0.0177 (3) | |
O4 | 0.81671 (12) | 0.63116 (13) | 0.08719 (9) | 0.0248 (3) | |
C5 | 0.54347 (18) | 0.49434 (18) | 0.10817 (12) | 0.0168 (3) | |
O5 | 0.60280 (12) | 0.49760 (13) | 0.20800 (8) | 0.0200 (3) | |
H5 | 0.5311 (18) | 0.421 (2) | 0.2284 (12) | 0.024* | |
C6 | 0.38340 (18) | 0.43229 (18) | 0.06343 (12) | 0.0169 (3) | |
O6 | 0.26616 (13) | 0.36837 (13) | 0.11753 (9) | 0.0229 (3) | |
H6 | 0.1592 (19) | 0.3159 (19) | 0.0754 (13) | 0.028* | |
N1 | 0.11089 (15) | −0.52917 (15) | 0.36960 (10) | 0.0211 (3) | |
C10 | 0.2677 (2) | −0.4212 (2) | 0.41080 (13) | 0.0241 (4) | |
H10 | 0.3327 (18) | −0.4490 (19) | 0.4552 (13) | 0.029* | |
C11 | 0.3392 (2) | −0.2698 (2) | 0.39293 (13) | 0.0213 (4) | |
H11 | 0.4556 (18) | −0.2026 (18) | 0.4251 (12) | 0.026* | |
C12 | 0.24512 (18) | −0.22625 (18) | 0.32817 (12) | 0.0176 (3) | |
C13 | 0.31481 (18) | −0.06245 (18) | 0.30901 (12) | 0.0170 (3) | |
C14 | 0.4832 (2) | 0.0273 (2) | 0.32274 (13) | 0.0225 (4) | |
H14 | 0.5627 (18) | −0.0103 (19) | 0.3446 (12) | 0.027* | |
C15 | 0.5411 (2) | 0.1781 (2) | 0.30252 (13) | 0.0224 (4) | |
H15 | 0.6599 (19) | 0.2402 (19) | 0.3125 (12) | 0.027* | |
N2 | 0.44245 (15) | 0.24380 (15) | 0.27038 (10) | 0.0205 (3) | |
C16 | 0.28094 (19) | 0.15788 (19) | 0.25806 (12) | 0.0203 (4) | |
H16 | 0.2088 (17) | 0.2016 (18) | 0.2328 (12) | 0.024* | |
C17 | 0.21196 (19) | 0.00584 (19) | 0.27529 (12) | 0.0194 (4) | |
H17 | 0.0941 (18) | −0.0507 (18) | 0.2634 (12) | 0.023* | |
C18 | 0.08324 (19) | −0.33958 (19) | 0.28373 (13) | 0.0195 (4) | |
H18 | 0.0077 (18) | −0.3228 (18) | 0.2364 (12) | 0.023* | |
C19 | 0.0219 (2) | −0.4879 (2) | 0.30598 (13) | 0.0207 (4) | |
H19 | −0.0942 (18) | −0.5659 (19) | 0.2762 (12) | 0.025* | |
N3 | −0.06220 (15) | 0.20248 (16) | 0.04592 (10) | 0.0234 (3) | |
C20 | −0.1387 (2) | 0.0781 (2) | 0.08389 (14) | 0.0258 (4) | |
H20 | −0.0655 (18) | 0.0469 (19) | 0.1263 (12) | 0.031* | |
C21 | −0.30727 (19) | −0.0022 (2) | 0.06882 (13) | 0.0247 (4) | |
H21 | −0.3562 (18) | −0.0915 (19) | 0.1031 (12) | 0.030* | |
C22 | −0.40869 (18) | 0.04258 (18) | 0.01029 (12) | 0.0194 (3) | |
C23 | −0.32893 (19) | 0.1733 (2) | −0.02812 (13) | 0.0219 (4) | |
H23 | −0.3991 (17) | 0.2072 (18) | −0.0750 (12) | 0.026* | |
C24 | −0.15926 (19) | 0.2476 (2) | −0.00853 (13) | 0.0231 (4) | |
H24 | −0.1011 (18) | 0.3389 (19) | −0.0339 (12) | 0.028* |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0220 (9) | 0.0142 (9) | 0.0179 (8) | 0.0093 (7) | 0.0078 (7) | 0.0057 (7) |
O1 | 0.0274 (6) | 0.0141 (6) | 0.0236 (6) | 0.0038 (5) | 0.0023 (5) | 0.0083 (5) |
C2 | 0.0170 (8) | 0.0172 (9) | 0.0182 (8) | 0.0063 (7) | 0.0022 (7) | 0.0068 (7) |
O2 | 0.0290 (7) | 0.0135 (6) | 0.0281 (6) | 0.0047 (5) | −0.0050 (5) | 0.0083 (5) |
C3 | 0.0214 (9) | 0.0171 (9) | 0.0188 (8) | 0.0087 (7) | 0.0060 (7) | 0.0096 (7) |
O3 | 0.0277 (7) | 0.0152 (6) | 0.0280 (6) | 0.0047 (5) | −0.0009 (5) | 0.0129 (5) |
C4 | 0.0210 (9) | 0.0105 (8) | 0.0202 (8) | 0.0064 (7) | 0.0010 (7) | 0.0042 (7) |
O4 | 0.0201 (6) | 0.0283 (7) | 0.0262 (6) | 0.0057 (5) | 0.0014 (5) | 0.0149 (5) |
C5 | 0.0232 (9) | 0.0114 (8) | 0.0159 (8) | 0.0059 (7) | 0.0025 (7) | 0.0061 (7) |
O5 | 0.0220 (6) | 0.0162 (6) | 0.0197 (6) | 0.0013 (5) | 0.0007 (5) | 0.0114 (5) |
C6 | 0.0221 (9) | 0.0117 (8) | 0.0181 (8) | 0.0069 (7) | 0.0062 (7) | 0.0063 (7) |
O6 | 0.0176 (6) | 0.0276 (7) | 0.0224 (6) | 0.0039 (5) | 0.0030 (5) | 0.0136 (5) |
N1 | 0.0275 (8) | 0.0161 (7) | 0.0210 (7) | 0.0090 (6) | 0.0047 (6) | 0.0080 (6) |
C10 | 0.0305 (10) | 0.0209 (9) | 0.0238 (9) | 0.0110 (8) | 0.0022 (8) | 0.0111 (8) |
C11 | 0.0235 (9) | 0.0184 (9) | 0.0213 (9) | 0.0068 (8) | 0.0022 (7) | 0.0083 (8) |
C12 | 0.0247 (9) | 0.0143 (8) | 0.0147 (8) | 0.0084 (7) | 0.0062 (7) | 0.0052 (7) |
C13 | 0.0241 (9) | 0.0149 (8) | 0.0127 (8) | 0.0083 (7) | 0.0049 (7) | 0.0050 (7) |
C14 | 0.0267 (10) | 0.0195 (9) | 0.0224 (9) | 0.0093 (8) | 0.0025 (7) | 0.0094 (8) |
C15 | 0.0208 (9) | 0.0202 (9) | 0.0236 (9) | 0.0040 (8) | 0.0014 (7) | 0.0099 (8) |
N2 | 0.0253 (8) | 0.0153 (7) | 0.0194 (7) | 0.0065 (6) | 0.0031 (6) | 0.0065 (6) |
C16 | 0.0260 (10) | 0.0193 (9) | 0.0208 (9) | 0.0124 (8) | 0.0068 (7) | 0.0097 (7) |
C17 | 0.0221 (9) | 0.0175 (9) | 0.0195 (9) | 0.0077 (7) | 0.0072 (7) | 0.0078 (7) |
C18 | 0.0241 (9) | 0.0178 (9) | 0.0196 (9) | 0.0102 (7) | 0.0053 (7) | 0.0084 (7) |
C19 | 0.0217 (9) | 0.0161 (9) | 0.0219 (9) | 0.0052 (7) | 0.0048 (7) | 0.0065 (7) |
N3 | 0.0210 (7) | 0.0233 (8) | 0.0218 (8) | 0.0063 (6) | 0.0048 (6) | 0.0060 (6) |
C20 | 0.0243 (10) | 0.0268 (10) | 0.0255 (10) | 0.0097 (8) | 0.0037 (7) | 0.0093 (8) |
C21 | 0.0250 (10) | 0.0203 (9) | 0.0278 (10) | 0.0077 (8) | 0.0060 (8) | 0.0089 (8) |
C22 | 0.0222 (8) | 0.0140 (8) | 0.0176 (8) | 0.0071 (7) | 0.0055 (7) | 0.0002 (7) |
C23 | 0.0241 (9) | 0.0192 (9) | 0.0201 (9) | 0.0089 (7) | 0.0055 (7) | 0.0041 (7) |
C24 | 0.0245 (9) | 0.0180 (9) | 0.0227 (9) | 0.0053 (8) | 0.0072 (7) | 0.0057 (8) |
C1—O1 | 1.2333 (16) | C12—C13 | 1.4989 (19) |
C1—C3i | 1.475 (2) | C13—C14 | 1.393 (2) |
C1—C2 | 1.4833 (19) | C13—C17 | 1.3997 (19) |
C2—C3 | 1.3515 (19) | C14—C15 | 1.395 (2) |
C2—O2 | 1.3585 (17) | C14—H14 | 0.956 (15) |
O2—H2 | 0.844 (16) | C15—N2 | 1.3428 (18) |
C3—O3 | 1.3509 (16) | C15—H15 | 0.980 (15) |
C3—C1i | 1.475 (2) | N2—C16 | 1.3368 (18) |
O3—H3 | 0.965 (15) | C16—C17 | 1.391 (2) |
C4—O4 | 1.2304 (17) | C16—H16 | 0.963 (14) |
C4—C5 | 1.475 (2) | C17—H17 | 0.965 (14) |
C4—C6ii | 1.496 (2) | C18—C19 | 1.390 (2) |
C5—C6 | 1.347 (2) | C18—H18 | 0.974 (14) |
C5—O5 | 1.3600 (16) | C19—H19 | 0.987 (14) |
O5—H5 | 0.882 (15) | N3—C24 | 1.3409 (19) |
C6—O6 | 1.3438 (16) | N3—C20 | 1.3482 (19) |
C6—C4ii | 1.496 (2) | C20—C21 | 1.382 (2) |
O6—H6 | 0.941 (15) | C20—H20 | 1.004 (14) |
N1—C10 | 1.3406 (19) | C21—C22 | 1.399 (2) |
N1—C19 | 1.3419 (18) | C21—H21 | 1.020 (14) |
C10—C11 | 1.392 (2) | C22—C23 | 1.403 (2) |
C10—H10 | 0.948 (15) | C22—C22iii | 1.492 (3) |
C11—C12 | 1.396 (2) | C23—C24 | 1.384 (2) |
C11—H11 | 0.978 (15) | C23—H23 | 1.039 (14) |
C12—C18 | 1.390 (2) | C24—H24 | 0.973 (14) |
O1—C1—C3i | 121.26 (12) | C13—C14—C15 | 119.41 (14) |
O1—C1—C2 | 119.76 (13) | C13—C14—H14 | 123.1 (9) |
C3i—C1—C2 | 118.97 (12) | C15—C14—H14 | 117.5 (9) |
C3—C2—O2 | 121.13 (13) | N2—C15—C14 | 123.41 (15) |
C3—C2—C1 | 121.26 (13) | N2—C15—H15 | 117.9 (8) |
O2—C2—C1 | 117.59 (13) | C14—C15—H15 | 118.7 (8) |
C2—O2—H2 | 111.6 (11) | C16—N2—C15 | 116.98 (12) |
O3—C3—C2 | 120.81 (13) | N2—C16—C17 | 123.66 (14) |
O3—C3—C1i | 119.47 (13) | N2—C16—H16 | 117.8 (8) |
C2—C3—C1i | 119.66 (12) | C17—C16—H16 | 118.5 (8) |
C3—O3—H3 | 112.8 (9) | C16—C17—C13 | 119.34 (15) |
O4—C4—C5 | 122.15 (13) | C16—C17—H17 | 119.3 (8) |
O4—C4—C6ii | 118.59 (13) | C13—C17—H17 | 121.4 (8) |
C5—C4—C6ii | 119.26 (12) | C19—C18—C12 | 119.53 (14) |
C6—C5—O5 | 125.16 (13) | C19—C18—H18 | 116.4 (8) |
C6—C5—C4 | 119.71 (13) | C12—C18—H18 | 124.1 (8) |
O5—C5—C4 | 115.12 (12) | N1—C19—C18 | 123.42 (15) |
C5—O5—H5 | 111.8 (9) | N1—C19—H19 | 117.5 (8) |
O6—C6—C5 | 121.00 (13) | C18—C19—H19 | 119.1 (8) |
O6—C6—C4ii | 118.01 (12) | C24—N3—C20 | 116.28 (13) |
C5—C6—C4ii | 120.98 (13) | N3—C20—C21 | 123.58 (15) |
C6—O6—H6 | 114.2 (9) | N3—C20—H20 | 116.0 (8) |
C10—N1—C19 | 116.96 (13) | C21—C20—H20 | 120.5 (8) |
N1—C10—C11 | 123.47 (15) | C20—C21—C22 | 120.20 (15) |
N1—C10—H10 | 118.1 (9) | C20—C21—H21 | 119.0 (8) |
C11—C10—H10 | 118.4 (9) | C22—C21—H21 | 120.7 (8) |
C10—C11—C12 | 119.25 (15) | C21—C22—C23 | 116.14 (14) |
C10—C11—H11 | 116.4 (8) | C21—C22—C22iii | 122.34 (16) |
C12—C11—H11 | 124.3 (8) | C23—C22—C22iii | 121.52 (17) |
C18—C12—C11 | 117.35 (14) | C24—C23—C22 | 119.76 (15) |
C18—C12—C13 | 121.28 (13) | C24—C23—H23 | 121.3 (8) |
C11—C12—C13 | 121.36 (13) | C22—C23—H23 | 118.8 (8) |
C14—C13—C17 | 117.18 (13) | N3—C24—C23 | 124.02 (15) |
C14—C13—C12 | 121.89 (13) | N3—C24—H24 | 114.7 (8) |
C17—C13—C12 | 120.93 (13) | C23—C24—H24 | 121.3 (9) |
Symmetry codes: (i) −x+2, −y+2, −z+1; (ii) −x+1, −y+1, −z; (iii) −x−1, −y, −z. |
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H2···O5 | 0.84 (2) | 1.91 (2) | 2.692 (2) | 153 (2) |
O3—H3···N1iv | 0.97 (2) | 1.74 (2) | 2.651 (2) | 155 (1) |
O5—H5···N2 | 0.88 (2) | 1.79 (2) | 2.635 (2) | 161 (1) |
O6—H6···N3 | 0.94 (2) | 1.82 (2) | 2.707 (2) | 157 (1) |
C14—H14···O2v | 0.94 (2) | 2.36 (2) | 3.268 (2) | 158 (1) |
C16—H16···O6 | 0.96 (1) | 2.40 (1) | 3.066 (2) | 126 (1) |
C18—H18···O4vi | 0.97 (1) | 2.34 (2) | 3.274 (2) | 162 (1) |
Symmetry codes: (iv) x+1, y+2, z; (v) x, y−1, z; (vi) x−1, y−1, z. |
Experimental details
Crystal data | |
Chemical formula | 3C10H8N2·2C6H4O6 |
Mr | 812.74 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 100 |
a, b, c (Å) | 8.8856 (8), 9.0728 (9), 12.9288 (11) |
α, β, γ (°) | 109.164 (5), 92.476 (5), 111.074 (5) |
V (Å3) | 903.17 (14) |
Z | 1 |
Radiation type | Mo Kα |
µ (mm−1) | 0.11 |
Crystal size (mm) | 0.6 × 0.4 × 0.3 |
Data collection | |
Diffractometer | Bruker SMART CCD diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.754, 1.000 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 9859, 4127, 2628 |
Rint | 0.037 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.038, 0.067, 1.07 |
No. of reflections | 4127 |
No. of parameters | 319 |
H-atom treatment | Only H-atom coordinates refined |
Δρmax, Δρmin (e Å−3) | 0.27, −0.25 |
Computer programs: SMART (Bruker, 1998), SMART, SAINT (Bruker, 1998), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997).
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H2···O5 | 0.84 (2) | 1.91 (2) | 2.692 (2) | 153 (2) |
O3—H3···N1i | 0.97 (2) | 1.74 (2) | 2.651 (2) | 155 (1) |
O5—H5···N2 | 0.88 (2) | 1.79 (2) | 2.635 (2) | 161 (1) |
O6—H6···N3 | 0.94 (2) | 1.82 (2) | 2.707 (2) | 157 (1) |
C14—H14···O2ii | 0.94 (2) | 2.36 (2) | 3.268 (2) | 158 (1) |
C16—H16···O6 | 0.96 (1) | 2.40 (1) | 3.066 (2) | 126 (1) |
C18—H18···O4iii | 0.97 (1) | 2.34 (2) | 3.274 (2) | 162 (1) |
Symmetry codes: (i) x+1, y+2, z; (ii) x, y−1, z; (iii) x−1, y−1, z. |
To investigate a variety of molecular interactions in the solid state, in particular N—H···O and O—H···N hydrogen bonds, we have produced new cocrystals of 4,4-bipyridine (BPY) and tetrahydroxybenzoquinone (THBQ). Cocrystals of organic acids and bipyridines have been studied extensively and have been observed to form a wide variety of intermolecular hydrogen bonds (Reetz et al., 1994; MacLean et al., 1999; Lough et al., 2000). We have reported recently the structure of BPY with 2,5-dihydroxybenzoquinone (Cowan et al., 2001), and as a natural progression of the series, we have investigated BPY with THBQ and present here the structure of 4,4'-bipyridine–tetrahydroxybenzoquinone (3/2).
There are two independent centrosymmetric molecules of THBQ in the structure. One THBQ molecule shows a spiral arrangement of the hydroxy H atoms similar to that observed by Kulpe (1965), while the other adopts a `crab-like' conformation with the O—-H bonds almost parallel to the quinone C═O groups. The geometry of the non-H atoms in both THBQ molecules is not significantly different from that observed by Kulpe (1965).
There are also two independent BPY molecules in the structure, one of which lies across an inversion centre; the other is complete within the asymmetric unit. In the complete BPY molecule, the pyridine rings are twisted at 19.9° with respect to each other, while the other BPY is required to be planar by symmetry. The twist in the unique BPY optimizes three weak C—H···O hydrogen bonds [C14···O2i, C16···O6 and C18···O4ii; symmetry codes: (i) x, y - 1, z; (ii) x - 1, y - 1, z].
There are four conventional hydrogen bonds in the asymmetric unit. Each of the four hydroxy groups is a donor and each of the pyridine N atoms is an acceptor. The other potential acceptor is O5 which acts both as a donor and as an acceptor. The carbonyl groups could be regarded as acceptors for intramolecular hydrogen bonds, but the O—H···O angles are unacceptable (O2–H2···O1 108°, O3–H3···O1 105° and O6–H6···O4 106°) and similarly for a possible intramolecular hydrogen bond between H5 and O6 (O5—H5···O6 102°).
Three different hydrogen-bonded chains are formed in the crystal; two arise from O—H···N hydrogen bonds and the third one from O—H···O hydrogen bonds (Fig. 2). Chains of THBQ propagate along the [111] direction, connected by O—H···O hydrogen bonds (O2···O5). Chains of BPY and THBQ propagate along the [210] direction connected by O—H···N hydrogen bonds (O6···N3) and further O—H···N hydrogen-bonded chains of BPY and THBQ are formed along the [131] direction [O3···N1iii and O5···N2; symmetry code: (iii) x + 1, y + 2, z].
When these three non-collinear chains intersect with one another, two-dimensional rings are created which connect together to form a three-dimensional supramolecular lattice. In the lattice, the THBQ molecules act as four-connecting (molecule containing C1) and six-connecting (molecule containing C4) nodes and the BPY molecules act only as links. The [111] and [131] chains link into planar sheets incorporating both types of node. The [210] chains connect the sheets via the six-connecting nodes after spanning two intervening planes.
The supramolecular structure can also be described by a supercell with axes of a' = 16.798 Å [210], b' = 17.096 Å [120], c' = 13.547 Å [111], α' = 108.8°, β' = 117.8° and γ' = 51.8° and with a volume of 2709 Å3, three times that of the primitive unit cell.
The three separate `lattices' which create an interpenetrating mesh within the supercell are shown in Fig. 3. Examination of the structure with PLATON (Spek, 1990) showed that there are no cavities of significant size within this structure. A similar structural motif occurs in cocrystals of a 3:2 ratio of BPY and trimesic acid (Sharma & Zaworotko, 1996), in which three two-dimensional interpenetrating hydrogen-bonded grids are formed but, unlike the present structure, large voids are formed in the crystal.