4,4'-Bipyridine-2-hydroxy-propane-1,2,3-tricarboxylic acid (3/2).

The combination of 2-hydroxy-propane-1,2,3-tricarboxylic acid (H(3)hypta, also called citric acid) and 4,4'-bipyridine (4,4'-bipy) in a 1:1.5 molar ratio leads to the formation of the title mol-ecular cocrystal, 1.5C(10)H(8)N(2)·C(6)H(8)O(7). The asymmetric unit contains one and a half 4,4'-bipy units, with one lying across a centre of inversion, and one H(3)hypta mol-ecule. The significant differences in the C-O bond distances support the existence of the un-ionized acid mol-ecule and confirm the formation of a cocrystal. There are π-π and C-H⋯π stacking inter-actions between the aromatic rings of 4,4'-bipy [with inter-planar distances of 3.7739 (8) and 3.7970 (8) Å] and between CH groups of H(3)hypta [with an H⋯π distance of 2.63 Å]. In the crystal structure, intermolecular O-H⋯N hydrogen bonds occur and an O-H⋯O hydrogen bond occurs within the citric acid moiety.

Related literature

For related literature on cocrystals and hydrogen bonding, see: Aakeroy & Seddon (1993 ▶); Aghabozorg et al. (2006 ▶); Aghabozorg, Heidari et al. (2008 ▶); Aghabozorg, Manteghi & Sheshmani (2008 ▶); Baures (1999 ▶); Biradha et al. (1993 ▶); Desiraju (1989 ▶); Desiraju & Steiner (1999 ▶); Houk et al. (1999 ▶).

Experimental

Crystal data

1.5C10H8N2·C6H8O7

M = 426.40

Monoclinic,

a = 7.0371 (2) Å

b = 33.5054 (10) Å

c = 8.4715 (2) Å

β = 90.302 (2)°

V = 1997.39 (9) Å3

Z = 4

Mo Kα radiation

μ = 0.11 mm−1

T = 150 K

0.31 × 0.26 × 0.22 mm

Data collection

Bruker SMART CCD area-detector diffractometer

Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T min = 0.896, T max = 0.977

63749 measured reflections

6045 independent reflections

4986 reflections with I > 2σ(I)

R int = 0.033

Refinement

R[F 2 > 2σ(F 2)] = 0.045

wR(F 2) = 0.116

S = 1.05

6045 reflections

284 parameters

H-atom parameters constrained

Δρmax = 0.40 e Å−3

Δρmin = −0.24 e Å−3

Data collection: SMART (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809004607/su2092sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809004607/su2092Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

1.5C10H8N2·C6H8O7	F(000) = 892
Mr = 426.40	Dx = 1.418 Mg m−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 20381 reflections
a = 7.0371 (2) Å	θ = 2.7–29.6°
b = 33.5054 (10) Å	µ = 0.11 mm−1
c = 8.4715 (2) Å	T = 150 K
β = 90.302 (2)°	Block, yellow
V = 1997.39 (9) Å3	0.31 × 0.26 × 0.22 mm
Z = 4

Bruker SMART CCD area-detector diffractometer	6045 independent reflections
Radiation source: fine-focus sealed tube	4986 reflections with I > 2σ(I)
graphite	Rint = 0.033
φ and ω scans	θmax = 30.5°, θmin = 1.2°
Absorption correction: multi-scan (SADABS; Bruker, 2005)	h = −9→10
Tmin = 0.896, Tmax = 0.977	k = −47→47
63749 measured reflections	l = −12→12

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: inferred from neighbouring sites
wR(F2) = 0.116	H-atom parameters constrained
S = 1.05	w = 1/[σ2(Fo2) + (0.046P)2 + 1.026P] where P = (Fo2 + 2Fc2)/3
6045 reflections	(Δ/σ)max < 0.001
284 parameters	Δρmax = 0.40 e Å−3
0 restraints	Δρmin = −0.24 e Å−3

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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
O1	1.22826 (14)	0.02331 (3)	0.66535 (13)	0.0327 (2)
H1A	1.3359	0.0254	0.7078	0.049*
O2	1.27436 (15)	0.08764 (3)	0.60893 (15)	0.0360 (3)
O3	0.85874 (15)	0.12663 (3)	0.72640 (11)	0.0274 (2)
H3A	0.8845	0.1464	0.7838	0.041*
O4	1.00936 (14)	0.16212 (3)	0.54053 (11)	0.0258 (2)
O5	0.59732 (15)	0.15627 (3)	0.37884 (11)	0.0274 (2)
O6	0.52218 (17)	0.10777 (3)	0.20888 (12)	0.0339 (3)
H6A	0.4824	0.1270	0.1541	0.051*
O7	0.99435 (14)	0.10297 (3)	0.33252 (10)	0.02327 (19)
H7A	1.0802	0.1200	0.3467	0.035*
C1	1.17363 (18)	0.05848 (4)	0.61136 (14)	0.0207 (2)
C2	0.97059 (17)	0.05761 (3)	0.55534 (15)	0.0195 (2)
H2A	0.8884	0.0516	0.6468	0.023*
H2B	0.9561	0.0354	0.4789	0.023*
C3	0.89834 (17)	0.09596 (3)	0.47738 (13)	0.0173 (2)
C4	0.68742 (18)	0.08896 (4)	0.43974 (15)	0.0208 (2)
H4A	0.6741	0.0632	0.3832	0.025*
H4B	0.6168	0.0867	0.5401	0.025*
C5	0.59840 (18)	0.12151 (4)	0.34080 (14)	0.0206 (2)
C6	0.92786 (18)	0.13235 (3)	0.58559 (14)	0.0194 (2)
N1	0.42826 (18)	0.31593 (3)	0.42264 (13)	0.0263 (2)
N2	0.42914 (18)	0.16451 (3)	1.00572 (14)	0.0278 (2)
C7	0.4111 (2)	0.32444 (4)	0.57535 (16)	0.0285 (3)
H7	0.3926	0.3515	0.6050	0.034*
C8	0.4188 (2)	0.29590 (4)	0.69282 (15)	0.0262 (3)
H8	0.4064	0.3034	0.8004	0.031*
C9	0.44484 (18)	0.25603 (4)	0.65244 (14)	0.0206 (2)
C10	0.44274 (18)	0.22416 (4)	0.77407 (14)	0.0203 (2)
C11	0.4672 (2)	0.23319 (4)	0.93413 (15)	0.0262 (3)
H11	0.4887	0.2599	0.9670	0.031*
C12	0.4597 (2)	0.20272 (4)	1.04392 (16)	0.0291 (3)
H12	0.4772	0.2093	1.1521	0.035*
C13	0.4046 (2)	0.15593 (4)	0.85302 (16)	0.0275 (3)
H13	0.3824	0.1289	0.8240	0.033*
C14	0.4101 (2)	0.18445 (4)	0.73488 (15)	0.0243 (3)
H14	0.3917	0.1769	0.6278	0.029*
C15	0.4680 (2)	0.24726 (4)	0.49209 (15)	0.0262 (3)
H15	0.4899	0.2206	0.4587	0.031*
C16	0.4587 (2)	0.27789 (4)	0.38298 (15)	0.0282 (3)
H16	0.4747	0.2716	0.2745	0.034*
N3	0.56382 (16)	0.01882 (4)	0.80165 (13)	0.0261 (2)
C17	0.6626 (2)	−0.01444 (4)	0.77585 (17)	0.0292 (3)
H17	0.6137	−0.0332	0.7021	0.035*
C18	0.83276 (19)	−0.02304 (4)	0.85097 (16)	0.0257 (3)
H18	0.8979	−0.0472	0.8286	0.031*
C19	0.90778 (16)	0.00392 (4)	0.95940 (13)	0.0183 (2)
C20	0.8034 (2)	0.03831 (4)	0.98728 (16)	0.0274 (3)
H20	0.8478	0.0575	1.0613	0.033*
C21	0.6342 (2)	0.04450 (4)	0.90668 (17)	0.0295 (3)
H21	0.5649	0.0682	0.9274	0.035*

	U11	U22	U33	U12	U13	U23
O1	0.0243 (5)	0.0270 (5)	0.0467 (6)	0.0001 (4)	−0.0148 (4)	0.0088 (4)
O2	0.0232 (5)	0.0249 (5)	0.0597 (7)	−0.0039 (4)	−0.0068 (5)	0.0009 (5)
O3	0.0403 (6)	0.0231 (5)	0.0190 (4)	−0.0043 (4)	0.0041 (4)	−0.0039 (3)
O4	0.0326 (5)	0.0186 (4)	0.0262 (5)	−0.0057 (4)	−0.0031 (4)	0.0012 (3)
O5	0.0372 (6)	0.0198 (4)	0.0250 (5)	0.0051 (4)	−0.0040 (4)	−0.0013 (3)
O6	0.0534 (7)	0.0212 (5)	0.0269 (5)	0.0017 (4)	−0.0190 (5)	0.0016 (4)
O7	0.0287 (5)	0.0223 (4)	0.0189 (4)	−0.0030 (3)	0.0044 (3)	−0.0009 (3)
C1	0.0199 (6)	0.0214 (6)	0.0207 (6)	0.0014 (4)	−0.0018 (4)	−0.0021 (4)
C2	0.0196 (6)	0.0158 (5)	0.0231 (6)	0.0000 (4)	−0.0042 (4)	0.0014 (4)
C3	0.0200 (6)	0.0153 (5)	0.0165 (5)	−0.0001 (4)	−0.0003 (4)	0.0000 (4)
C4	0.0208 (6)	0.0177 (5)	0.0238 (6)	−0.0007 (4)	−0.0053 (4)	0.0034 (4)
C5	0.0218 (6)	0.0200 (5)	0.0200 (6)	0.0016 (4)	−0.0011 (4)	0.0022 (4)
C6	0.0221 (6)	0.0172 (5)	0.0190 (5)	0.0012 (4)	−0.0030 (4)	−0.0008 (4)
N1	0.0366 (6)	0.0232 (5)	0.0193 (5)	0.0002 (4)	0.0017 (4)	0.0028 (4)
N2	0.0362 (6)	0.0247 (5)	0.0225 (5)	0.0027 (5)	−0.0070 (5)	0.0041 (4)
C7	0.0443 (8)	0.0197 (6)	0.0214 (6)	0.0031 (5)	0.0013 (5)	0.0003 (5)
C8	0.0405 (8)	0.0215 (6)	0.0164 (6)	0.0039 (5)	0.0013 (5)	−0.0005 (4)
C9	0.0239 (6)	0.0205 (5)	0.0175 (5)	0.0026 (4)	−0.0006 (4)	0.0008 (4)
C10	0.0216 (6)	0.0214 (6)	0.0178 (5)	0.0036 (4)	−0.0013 (4)	0.0010 (4)
C11	0.0379 (7)	0.0211 (6)	0.0196 (6)	0.0038 (5)	−0.0045 (5)	−0.0003 (4)
C12	0.0430 (8)	0.0255 (6)	0.0188 (6)	0.0047 (6)	−0.0061 (5)	0.0011 (5)
C13	0.0348 (7)	0.0216 (6)	0.0259 (6)	0.0005 (5)	−0.0072 (5)	0.0013 (5)
C14	0.0296 (7)	0.0234 (6)	0.0198 (6)	0.0014 (5)	−0.0037 (5)	−0.0009 (4)
C15	0.0389 (8)	0.0200 (6)	0.0198 (6)	0.0041 (5)	0.0028 (5)	−0.0019 (4)
C16	0.0419 (8)	0.0258 (6)	0.0168 (6)	0.0025 (5)	0.0037 (5)	−0.0005 (5)
N3	0.0197 (5)	0.0314 (6)	0.0272 (6)	0.0009 (4)	−0.0037 (4)	0.0068 (4)
C17	0.0244 (7)	0.0292 (7)	0.0338 (7)	−0.0025 (5)	−0.0087 (5)	−0.0018 (5)
C18	0.0229 (6)	0.0208 (6)	0.0333 (7)	0.0032 (5)	−0.0062 (5)	−0.0041 (5)
C19	0.0176 (5)	0.0203 (5)	0.0169 (5)	0.0015 (4)	−0.0009 (4)	0.0017 (4)
C20	0.0278 (7)	0.0268 (6)	0.0274 (6)	0.0086 (5)	−0.0065 (5)	−0.0057 (5)
C21	0.0277 (7)	0.0300 (7)	0.0306 (7)	0.0114 (5)	−0.0046 (5)	−0.0002 (5)

O1—C1	1.3205 (15)	C8—C9	1.3915 (17)
O1—H1A	0.8400	C8—H8	0.9500
O2—C1	1.2073 (16)	C9—C15	1.4002 (17)
O3—C6	1.3048 (15)	C9—C10	1.4838 (17)
O3—H3A	0.8400	C10—C14	1.3902 (17)
O4—C6	1.2131 (15)	C10—C11	1.3990 (17)
O5—C5	1.2084 (15)	C11—C12	1.3820 (18)
O6—C5	1.3200 (15)	C11—H11	0.9500
O6—H6A	0.8400	C12—H12	0.9500
O7—C3	1.4235 (14)	C13—C14	1.3844 (18)
O7—H7A	0.8400	C13—H13	0.9500
C1—C2	1.5035 (17)	C14—H14	0.9500
C2—C3	1.5306 (16)	C15—C16	1.3825 (18)
C2—H2A	0.9900	C15—H15	0.9500
C2—H2B	0.9900	C16—H16	0.9500
C3—C4	1.5345 (17)	N3—C21	1.3313 (18)
C3—C6	1.5389 (16)	N3—C17	1.3323 (18)
C4—C5	1.5096 (16)	C17—C18	1.3832 (18)
C4—H4A	0.9900	C17—H17	0.9500
C4—H4B	0.9900	C18—C19	1.3906 (17)
N1—C7	1.3309 (17)	C18—H18	0.9500
N1—C16	1.3357 (17)	C19—C20	1.3875 (17)
N2—C13	1.3355 (17)	C19—C19i	1.489 (2)
N2—C12	1.3379 (18)	C20—C21	1.3851 (18)
C7—C8	1.3810 (18)	C20—H20	0.9500
C7—H7	0.9500	C21—H21	0.9500
C1—O1—H1A	109.5	C8—C9—C10	121.22 (11)
C6—O3—H3A	109.5	C15—C9—C10	121.63 (11)
C5—O6—H6A	109.5	C14—C10—C11	117.23 (11)
C3—O7—H7A	109.5	C14—C10—C9	121.67 (11)
O2—C1—O1	123.93 (12)	C11—C10—C9	121.06 (11)
O2—C1—C2	124.57 (11)	C12—C11—C10	119.19 (12)
O1—C1—C2	111.49 (10)	C12—C11—H11	120.4
C1—C2—C3	115.65 (10)	C10—C11—H11	120.4
C1—C2—H2A	108.4	N2—C12—C11	123.41 (12)
C3—C2—H2A	108.4	N2—C12—H12	118.3
C1—C2—H2B	108.4	C11—C12—H12	118.3
C3—C2—H2B	108.4	N2—C13—C14	123.22 (12)
H2A—C2—H2B	107.4	N2—C13—H13	118.4
O7—C3—C2	110.63 (10)	C14—C13—H13	118.4
O7—C3—C4	108.00 (9)	C13—C14—C10	119.55 (12)
C2—C3—C4	106.27 (9)	C13—C14—H14	120.2
O7—C3—C6	108.65 (9)	C10—C14—H14	120.2
C2—C3—C6	111.39 (9)	C16—C15—C9	119.18 (12)
C4—C3—C6	111.86 (10)	C16—C15—H15	120.4
C5—C4—C3	113.77 (10)	C9—C15—H15	120.4
C5—C4—H4A	108.8	N1—C16—C15	123.18 (12)
C3—C4—H4A	108.8	N1—C16—H16	118.4
C5—C4—H4B	108.8	C15—C16—H16	118.4
C3—C4—H4B	108.8	C21—N3—C17	117.24 (11)
H4A—C4—H4B	107.7	N3—C17—C18	123.37 (13)
O5—C5—O6	123.98 (11)	N3—C17—H17	118.3
O5—C5—C4	123.46 (11)	C18—C17—H17	118.3
O6—C5—C4	112.56 (10)	C17—C18—C19	119.56 (12)
O4—C6—O3	125.98 (11)	C17—C18—H18	120.2
O4—C6—C3	121.77 (11)	C19—C18—H18	120.2
O3—C6—C3	112.24 (10)	C20—C19—C18	116.91 (11)
C7—N1—C16	117.68 (11)	C20—C19—C19i	121.93 (14)
C13—N2—C12	117.39 (12)	C18—C19—C19i	121.17 (13)
N1—C7—C8	123.27 (12)	C21—C20—C19	119.66 (12)
N1—C7—H7	118.4	C21—C20—H20	120.2
C8—C7—H7	118.4	C19—C20—H20	120.2
C7—C8—C9	119.50 (12)	N3—C21—C20	123.26 (13)
C7—C8—H8	120.2	N3—C21—H21	118.4
C9—C8—H8	120.2	C20—C21—H21	118.4
C8—C9—C15	117.13 (11)
O2—C1—C2—C3	5.62 (19)	C8—C9—C10—C11	−17.8 (2)
O1—C1—C2—C3	−174.98 (11)	C15—C9—C10—C11	163.88 (13)
C1—C2—C3—O7	66.37 (13)	C14—C10—C11—C12	0.6 (2)
C1—C2—C3—C4	−176.64 (10)	C9—C10—C11—C12	178.46 (13)
C1—C2—C3—C6	−54.58 (14)	C13—N2—C12—C11	−0.1 (2)
O7—C3—C4—C5	−52.92 (13)	C10—C11—C12—N2	−0.3 (2)
C2—C3—C4—C5	−171.64 (10)	C12—N2—C13—C14	0.2 (2)
C6—C3—C4—C5	66.59 (13)	N2—C13—C14—C10	0.1 (2)
C3—C4—C5—O5	−56.85 (17)	C11—C10—C14—C13	−0.5 (2)
C3—C4—C5—O6	123.21 (12)	C9—C10—C14—C13	−178.34 (13)
O7—C3—C6—O4	4.99 (16)	C8—C9—C15—C16	−1.8 (2)
C2—C3—C6—O4	127.10 (12)	C10—C9—C15—C16	176.56 (13)
C4—C3—C6—O4	−114.14 (13)	C7—N1—C16—C15	1.7 (2)
O7—C3—C6—O3	−174.06 (10)	C9—C15—C16—N1	0.0 (2)
C2—C3—C6—O3	−51.95 (14)	C21—N3—C17—C18	−0.6 (2)
C4—C3—C6—O3	66.82 (13)	N3—C17—C18—C19	−0.1 (2)
C16—N1—C7—C8	−1.6 (2)	C17—C18—C19—C20	0.8 (2)
N1—C7—C8—C9	−0.3 (2)	C17—C18—C19—C19i	−178.91 (15)
C7—C8—C9—C15	2.0 (2)	C18—C19—C20—C21	−0.8 (2)
C7—C8—C9—C10	−176.40 (13)	C19i—C19—C20—C21	178.91 (15)
C8—C9—C10—C14	159.96 (13)	C17—N3—C21—C20	0.7 (2)
C15—C9—C10—C14	−18.3 (2)	C19—C20—C21—N3	0.1 (2)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1A···N3ii	0.84	1.80	2.6275 (14)	168
O3—H3A···N1iii	0.84	1.75	2.5880 (14)	173
O6—H6A···N2iv	0.84	1.82	2.6443 (14)	168
O7—H7A···O4	0.84	2.22	2.6538 (13)	112
C2—H2A···Cgv	0.99	2.63	3.5579 (13)	160

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1A⋯N3i	0.84	1.80	2.6275 (14)	168
O3—H3A⋯N1ii	0.84	1.75	2.5880 (14)	173
O6—H6A⋯N2iii	0.84	1.82	2.6443 (14)	168
O7—H7A⋯O4	0.84	2.22	2.6538 (13)	112
C2—H2A⋯Cgiv	0.99	2.63	3.5579 (13)	160

Symmetry codes: (i) ; (ii) ; (iii) ; (iv) . Cg is the centroid of the N3,C17–C21 ring.