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Volume 69 
Part 9 
Page o1443  
September 2013  

Received 11 August 2013
Accepted 11 August 2013
Online 17 August 2013

Key indicators
Single-crystal X-ray study
T = 98 K
Mean [sigma](C-C) = 0.002 Å
R = 0.044
wR = 0.120
Data-to-parameter ratio = 14.7
Details
Open access

Benzene-1,2,4,5-tetracarboxylic acid bis(1,3,7-trimethyl-2,3,6,7-tetrahydro-1H-purine-2,6-dione)

aDepartment of Chemistry, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249-0698, USA, and bDepartment of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
Correspondence e-mail: edward.tiekink@gmail.com

The asymmetric unit of the title co-crystal, C10H6O8·2C8H10N4O2, comprises a centrosymmetric benzene-1,2,4,5-tetracarboxylic acid (LH4) molecule and a molecule of caffeine in a general position. LH4 is nonplanar, with the dihedral angles between the ring and pendent carboxylic acid groups being 44.22 (7) and 49.74 (7)°. By contrast, the caffeine molecule is planar (r.m.s. deviation = 0.040 Å). Supramolecular layers parallel to (-1-10) are sustained by carboxylic acid O-H...O(carbonyl) and O-H...N(imidazole) hydrogen bonds, as well as by methyl-carbonyl C-H...O interactions. These stack via [pi]-[pi] interactions between the benzene and imidazole rings [inter-centroid distance = 3.4503 (10) Å].

Related literature

For cocrystallization studies with benzene-1,2,4,5-tetracarboxylic acid, see: Arman & Tiekink (2013[Arman, H. D. & Tiekink, E. R. T. (2013). Z. Kristallogr. Cryst. Mat. 228, 289-294.]).

[Scheme 1]

Experimental

Crystal data
  • C10H6O8·2C8H10N4O2

  • Mr = 642.55

  • Triclinic, [P \overline 1]

  • a = 7.4570 (15) Å

  • b = 9.0490 (15) Å

  • c = 11.782 (2) Å

  • [alpha] = 68.800 (11)°

  • [beta] = 81.124 (13)°

  • [gamma] = 73.441 (9)°

  • V = 709.3 (2) Å3

  • Z = 1

  • Mo K[alpha] radiation

  • [mu] = 0.12 mm-1

  • T = 98 K

  • 0.55 × 0.30 × 0.25 mm

Data collection
  • Rigaku AFC12 Kappa/SATURN724 diffractometer

  • Absorption correction: multi-scan (ABSCOR; Higashi, 1995[Higashi, T. (1995). ABSCOR. Rigaku Corporation, Tokyo, Japan.]) Tmin = 0.838, Tmax = 1

  • 4935 measured reflections

  • 3213 independent reflections

  • 3006 reflections with I > 2[sigma](I)

  • Rint = 0.020

  • Standard reflections: 0

Refinement
  • R[F2 > 2[sigma](F2)] = 0.044

  • wR(F2) = 0.120

  • S = 1.04

  • 3213 reflections

  • 218 parameters

  • 2 restraints

  • H atoms treated by a mixture of independent and constrained refinement

  • [Delta][rho]max = 0.37 e Å-3

  • [Delta][rho]min = -0.33 e Å-3

Table 1
Hydrogen-bond geometry (Å, °)

D-H...A D-H H...A D...A D-H...A
O2-H1O...N3i 0.86 (1) 1.83 (1) 2.6774 (17) 171 (2)
O4-H2O...O5 0.84 (2) 1.84 (2) 2.6571 (15) 162 (2)
C12-H12B...O6ii 0.98 2.30 3.239 (2) 159
Symmetry codes: (i) -x, -y+2, -z+1; (ii) -x+2, -y+1, -z+1.

Data collection: CrystalClear (Molecular Structure Corporation & Rigaku, 2005[Molecular Structure Corporation & Rigaku (2005). CrystalClear. MSC, The Woodlands, Texas, USA, and Rigaku Corporation, Tokyo, Japan.]); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: ORTEPII (Johnson, 1976[Johnson, C. K. (1976). ORTEPII. Report ORNL-5138. Oak Ridge National Laboratory, Tennessee, USA.]) and DIAMOND (Brandenburg, 2006[Brandenburg, K. (2006). DIAMOND. Crystal Impact GbR, Bonn, Germany.]); software used to prepare material for publication: publCIF (Westrip, 2010[Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.]).


Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: HG5340 ).


Acknowledgements

The authors gratefully thank the Ministry of Higher Education (Malaysia) for funding structural studies through the High-Impact Research scheme (grant No. UM.C/HIR-MOHE/SC/03).

References

Arman, H. D. & Tiekink, E. R. T. (2013). Z. Kristallogr. Cryst. Mat. 228, 289-294.  [CrossRef] [ChemPort]
Brandenburg, K. (2006). DIAMOND. Crystal Impact GbR, Bonn, Germany.
Higashi, T. (1995). ABSCOR. Rigaku Corporation, Tokyo, Japan.
Johnson, C. K. (1976). ORTEPII. Report ORNL-5138. Oak Ridge National Laboratory, Tennessee, USA.
Molecular Structure Corporation & Rigaku (2005). CrystalClear. MSC, The Woodlands, Texas, USA, and Rigaku Corporation, Tokyo, Japan.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.  [CrossRef] [ChemPort] [details]
Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.  [ISI] [CrossRef] [ChemPort] [details]


Acta Cryst (2013). E69, o1443  [ doi:10.1107/S1600536813022563 ]

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