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2,5-Di­hydroxy-1,4-benzo­quinone (DHBQ) and 4,4′-bi­pyridine (BPY) crystallize in a 1:1 ratio as a neutral molecular adduct, C6H4O4·C10H8N2, in space group C2/c, with half of each mol­ecule in the asymmetric unit. The mol­ecules are linked by a strong O—H...N hydrogen bond [O...N 2.6323 (15) Å] and a weak C—H...O hydrogen bond [C...O 3.2082 (17) Å] to form infinite stacks of parallel one-dimensional hydrogen-bonded ribbons. The two rings of the bi­pyridine are twisted at 28.3° with respect to each other, and the benzo­quinone ring is inclined at an angle of 18.3° with respect to the plane of the neighbouring pyridine ring. The 4,4′-bi­pyridine mol­ecule lies on a twofold axis and the benzo­quinone mol­ecule lies across an inversion centre.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270100019077/gd1125sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270100019077/gd1125Isup2.hkl
Contains datablock I

CCDC reference: 162576

Comment top

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 co?crystals of 4,4'-bipyridine (BPY) and 2,5-dihydroxy-1,4-benzoquinone (DHBQ). Cocrystals of organic acids and bipyridines have been studied extensively and have been observed to form a wide variety of hydrogen bonds. They have the ability to form cocrystals with different stoichiometries of the constituents and a variety have been observed by ourselves and by other workers, namely 1:1, 1:2 and 2:1 cocrystals of 4,4'-bipyridine and pyromellitic acid (Lough et al., 2000; Williams et al., 2000), and also 1:1 (Reetz et al., 1994) and 2:3 ratios (MacLean et al., 1999) for cocrystals of 4,4'-bipyridine and squaric acid. Surprisingly, we have found only one stoichiometry for cocrystals of DHBQ and BPY and present here the crystal structure of the 1:1 adduct, (I). \sch

DHBQ is a weak organic acid with the possibility of single or double deprotonation, whereupon its shape and properties change significantly, as the charge becomes more delocalized. The neutral molecule was observed in the structure of the pure form by Semmingsen (1977), while the doubly deprotonated form was observed as the potassium salt by Kulpe (1974). In the neutral state, DHBQ can be a hydrogen-bond donor and/or an acceptor, making it an excellent and novel tool for studying weak interactions in `supramolecular' crystals.

BPY is a rather rigid weak bidentate base, popular in similar crystal-engineering studies because of its bridging ability (Zaman et al., 1999; Coupar et al., 1996; Sharma & Zaworotko, 1996; MacLean et al., 1999). The molecule can remain neutral or become singly or doubly protonated, its final state depending not only on the strength of the cocrystal acid, but also on its crystalline environment (Williams et al., 2000).

In the present structure, the molecular parameters of DHBQ compare closely with those of the neutral molecule (Semmingsen, 1977), and similarly for BPY, which in (I) is also typical of the neutral form. Both molecules are symmetrical, since the DHBQ lies across a crystallographic inversion centre and the BPY lies upon a twofold axis (Fig. 1). The angle subtended at the N atom of the bipyridine molecule [117.5 (1)°] compares well with the average of 116.5° taken from neutral bipyridine molecules in the Cambridge Structural Database (CSD; Allen & Kennard, 1993); the average CSD value for the recorded protonated form is 121.5°. This parameter also accords with H2 being bound to O2 and not to the bipyridine [O2—H2 0.96 (2) Å].

The dominant interaction for the packing is the strong O2—H2···N1 hydrogen bond [O···N 2.6323 (15) Å], which is assisted by the weaker C14—H14···O1 hydrogen bond [C···O 3.2082 (17) Å], thus linking the molecules together into one-dimensional chains. The chains lie in the ac plane and propagate in the [103] direction (Fig. 2).

The molecular synthon of (I) is similar to one of the two which were observed in the two structures of 4,4'-bipyridine and squaric acid reported by Reetz et al. (1994), in which the bipyridine and squarate molecules form similar hydrogen-bonded chains. The other synthon, which has the same shape, occurs when the bipyridine has become protonated and an N—H···O hydrogen bond is supported by a weak C—H···O hydrogen bond.

In the closely related system combining 2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone (chloranilic acid) and BPY to form 1:1 crystals (Zaman et al., 1999), the molecules also link together to form chains, but with a distinctly different synthon. The 4,4'-bipyridine in this adduct is the doubly protonated [BPY-2H]2+, and the molecules are linked by bifurcated hydrogen bonds at each N atom, resulting in the planes of the quinone and the bipyridine lying mutually perpendicular and alternating their orientation along the molecular chain.

The differences observed in the four structures discussed above can be attributed primarily to the relative strengths of the three acids, squaric acid, 2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone and 2,5-dihydroxy-1,4-benzoquinone.

Related literature top

For related literature, see: Allen & Kennard (1993); Coupar et al. (1996); Kulpe (1974); Lough et al. (2000); MacLean et al. (1999); Reetz et al. (1994); Semmingsen (1977); Sharma & Zaworotko (1996); Williams et al. (2000); Zaman et al. (1999).

Experimental top

Equimolar portions of BPY and DHBQ were dissolved in methanol/water, producing an orange solution. Crystals of (I) suitable for X-ray structure determination were prepared by slow evaporation of the solvent at room temperature.

Refinement top

All H atoms were found in difference Fourier maps and were refined with isotropic displacement parameters. The C—H and O—H distances all refined to within standard ranges and there were no anomalous values of Uiso.

Computing details top

Data collection: SMART (Bruker, 1997); cell refinement: SMART; data reduction: SAINT (Bruker, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997).

Figures top
[Figure 1] Fig. 1. The molecules of (I) shown with 50% probability displacement ellipsoids. The dashed lines indicate hydrogen bonds and H atoms are drawn as small spheres of arbitrary radii [symmetry codes: (i) 1/2 - x, 1/2 - y, 2 - z; (ii) -x, y, 1/2 - z].
[Figure 2] Fig. 2. The packing diagram for (I) viewed along the c axis. H atoms have been omitted for clarity.
2,5-Dihydroxy-1,4-benzoquinone–4,4'-bipyridine (1/1) top
Crystal data top
C6H4O4·C10H8N2F(000) = 616
Mr = 296.28Dx = 1.478 Mg m3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 932 reflections
a = 20.8676 (17) Åθ = 13.7–29.5°
b = 7.0151 (7) ŵ = 0.11 mm1
c = 9.1087 (8) ÅT = 150 K
β = 92.843 (5)°Needle, orange
V = 1331.8 (2) Å30.54 × 0.20 × 0.12 mm
Z = 4
Data collection top
Bruker SMART CCD
diffractometer
1286 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.060
Graphite monochromatorθmax = 27.5°, θmin = 2.0°
ω scansh = 2627
6874 measured reflectionsk = 99
1520 independent reflectionsl = 1111
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.041Hydrogen site location: difference Fourier map
wR(F2) = 0.113All H-atom parameters refined
S = 1.06 w = 1/[σ2(Fo2) + (0.0652P)2 + 0.6747P]
where P = (Fo2 + 2Fc2)/3
1520 reflections(Δ/σ)max < 0.001
124 parametersΔρmax = 0.29 e Å3
0 restraintsΔρmin = 0.22 e Å3
Crystal data top
C6H4O4·C10H8N2V = 1331.8 (2) Å3
Mr = 296.28Z = 4
Monoclinic, C2/cMo Kα radiation
a = 20.8676 (17) ŵ = 0.11 mm1
b = 7.0151 (7) ÅT = 150 K
c = 9.1087 (8) Å0.54 × 0.20 × 0.12 mm
β = 92.843 (5)°
Data collection top
Bruker SMART CCD
diffractometer
1286 reflections with I > 2σ(I)
6874 measured reflectionsRint = 0.060
1520 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0410 restraints
wR(F2) = 0.113All H-atom parameters refined
S = 1.06Δρmax = 0.29 e Å3
1520 reflectionsΔρmin = 0.22 e Å3
124 parameters
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
xyzUiso*/Ueq
C10.18925 (6)0.30700 (18)0.93241 (14)0.0216 (3)
O10.13723 (5)0.34454 (16)0.86910 (11)0.0297 (3)
C20.23774 (6)0.19269 (19)0.85043 (14)0.0226 (3)
O20.22213 (5)0.14586 (16)0.71195 (10)0.0282 (3)
H20.1813 (11)0.193 (3)0.676 (3)0.061 (7)*
C30.29392 (6)0.1371 (2)0.91739 (14)0.0233 (3)
H30.3248 (8)0.062 (2)0.8663 (18)0.027 (4)*
N10.11795 (6)0.21530 (17)0.54574 (13)0.0258 (3)
C100.13339 (7)0.1763 (2)0.40779 (16)0.0258 (3)
H100.1769 (8)0.151 (2)0.3935 (18)0.026 (4)*
C110.08876 (7)0.1733 (2)0.28926 (15)0.0248 (3)
H110.1015 (8)0.136 (2)0.192 (2)0.035 (5)*
C120.02457 (6)0.21488 (18)0.31218 (14)0.0215 (3)
C130.00852 (7)0.2576 (2)0.45608 (15)0.0262 (3)
H130.0336 (9)0.288 (3)0.481 (2)0.038 (5)*
C140.05649 (7)0.2554 (2)0.56801 (15)0.0288 (3)
H140.0478 (9)0.285 (3)0.670 (2)0.042 (5)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0194 (6)0.0255 (6)0.0197 (6)0.0009 (5)0.0017 (5)0.0015 (5)
O10.0230 (5)0.0405 (6)0.0251 (5)0.0047 (4)0.0050 (4)0.0032 (4)
C20.0230 (7)0.0266 (7)0.0182 (6)0.0018 (5)0.0003 (5)0.0002 (5)
O20.0260 (5)0.0398 (6)0.0184 (5)0.0047 (4)0.0045 (4)0.0045 (4)
C30.0225 (7)0.0274 (7)0.0200 (6)0.0026 (5)0.0004 (5)0.0021 (5)
N10.0248 (6)0.0296 (6)0.0224 (6)0.0002 (5)0.0043 (4)0.0007 (4)
C100.0208 (7)0.0306 (7)0.0257 (7)0.0025 (5)0.0024 (5)0.0021 (5)
C110.0225 (7)0.0309 (7)0.0208 (6)0.0013 (5)0.0012 (5)0.0024 (5)
C120.0212 (6)0.0225 (6)0.0205 (6)0.0008 (5)0.0024 (5)0.0007 (5)
C130.0213 (6)0.0347 (7)0.0225 (7)0.0019 (5)0.0004 (5)0.0018 (6)
C140.0264 (7)0.0398 (8)0.0198 (6)0.0005 (6)0.0011 (5)0.0014 (6)
Geometric parameters (Å, º) top
C1—O11.2321 (17)C10—C111.3907 (19)
C1—C3i1.4495 (18)C10—H100.941 (17)
C1—C21.5164 (19)C11—C121.3966 (19)
C2—O21.3283 (16)C11—H110.977 (19)
C2—C31.3519 (19)C12—C131.4013 (18)
O2—H20.96 (2)C12—C12ii1.490 (2)
C3—C1i1.4495 (18)C13—C141.3931 (19)
C3—H30.967 (16)C13—H130.945 (18)
N1—C141.3382 (19)C14—H140.975 (19)
N1—C101.3408 (18)
O1—C1—C3i123.40 (12)C11—C10—H10120.2 (10)
O1—C1—C2118.45 (12)C10—C11—C12119.42 (13)
C3i—C1—C2118.13 (12)C10—C11—H11120.6 (11)
O2—C2—C3121.56 (13)C12—C11—H11119.9 (11)
O2—C2—C1117.40 (12)C11—C12—C13117.38 (12)
C3—C2—C1121.02 (12)C11—C12—C12ii121.03 (14)
C2—O2—H2114.3 (14)C13—C12—C12ii121.59 (14)
C2—C3—C1i120.79 (12)C14—C13—C12119.07 (13)
C2—C3—H3121.5 (10)C14—C13—H13117.9 (12)
C1i—C3—H3117.7 (10)C12—C13—H13123.1 (12)
C14—N1—C10117.49 (12)N1—C14—C13123.42 (13)
N1—C10—C11123.22 (13)N1—C14—H14114.4 (11)
N1—C10—H10116.5 (10)C13—C14—H14122.2 (11)
Symmetry codes: (i) x+1/2, y+1/2, z+2; (ii) x, y, z+1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O2—H2···N10.96 (2)1.74 (3)2.6323 (15)154 (2)
C14—H14···O10.975 (19)2.572 (19)3.2082 (17)122.9 (13)

Experimental details

Crystal data
Chemical formulaC6H4O4·C10H8N2
Mr296.28
Crystal system, space groupMonoclinic, C2/c
Temperature (K)150
a, b, c (Å)20.8676 (17), 7.0151 (7), 9.1087 (8)
β (°) 92.843 (5)
V3)1331.8 (2)
Z4
Radiation typeMo Kα
µ (mm1)0.11
Crystal size (mm)0.54 × 0.20 × 0.12
Data collection
DiffractometerBruker SMART CCD
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
6874, 1520, 1286
Rint0.060
(sin θ/λ)max1)0.649
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.041, 0.113, 1.06
No. of reflections1520
No. of parameters124
H-atom treatmentAll H-atom parameters refined
Δρmax, Δρmin (e Å3)0.29, 0.22

Computer programs: SMART (Bruker, 1997), SMART, SAINT (Bruker, 1997), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O2—H2···N10.96 (2)1.74 (3)2.6323 (15)154 (2)
C14—H14···O10.975 (19)2.572 (19)3.2082 (17)122.9 (13)
 

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