Pyrimidin-2-amine–1-phenyl­cyclo­pentane-1-carb­oxy­lic acid (1/1)

Guangwen He; Srinivasulu Aitipamula; Pui Shan Chow; Reginald B H Tan

doi:10.1107/S1600536811003667

. 2011 Feb 2;67(Pt 3):o552–o553. doi: 10.1107/S1600536811003667

Pyrimidin-2-amine–1-phenylcyclopentane-1-carboxylic acid (1/1)

Guangwen He ^a,^*, Srinivasulu Aitipamula ^a, Pui Shan Chow ^a, Reginald B H Tan ^a,^b,^*

PMCID: PMC3052005 PMID: 21522318

Abstract

In the crystal structure of the title co-crystal, C₄H₅N₃·C₁₂H₁₄O₂, the components are linked by N—H⋯O and O—H⋯N hydrogen bonds. Self-assembly of these dimeric units results in a four-component supramolecular unit featuring a homosynthon between two molecules of the pyrimidin-2-amine involving two N—H⋯O hydrogen bonds, and two heterosynthons between each one molecule of pyrimidin-2-amine and 1-phenylcyclopentane-1-carboxylic acid involving N—H⋯O and O—H⋯N hydrogen bonds.

Related literature

For the structure of pyrimidin-2-amine, see: Scheinbeim & Schempp (1976 ▶) and for the structure of 1-phenylcyclopentane-1-carboxylic acid, see: Margulis (1975 ▶). For molecular co-crystals of pyrimidin-2-amine, see: Serafin & Wheeler (2007 ▶); Shan et al. (2002 ▶); Goswami et al. (1999a ▶,b ▶, 2000 ▶); Chinnakali et al. (1999 ▶); Lynch et al. (1997 ▶). For a salt of 2-aminopyridine and 1-phenyl-1-cyclopropanecarboxylic acid, see: He et al. (2010 ▶). For a recent screening study for co-crystal and salt formation using pulse-gradient spin–echo nuclear magnetic resonance, see: He et al. (2009 ▶).

Experimental

Crystal data

C₄H₅N₃·C₁₂H₁₄O₂
M _r = 285.34
Monoclinic,
a = 9.1461 (18) Å
b = 10.490 (2) Å
c = 15.474 (3) Å
β = 98.14 (3)°
V = 1469.7 (5) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 110 K
0.44 × 0.44 × 0.22 mm

Data collection

Rigaku Saturn 70 CCD area-detector diffractometer
Absorption correction: multi-scan (Blessing, 1995 ▶) T _min = 0.963, T _max = 0.981
20335 measured reflections
3641 independent reflections
3516 reflections with I > 2σ(I)
R _int = 0.036

Refinement

R[F ² > 2σ(F ²)] = 0.068
wR(F ²) = 0.178
S = 1.21
3641 reflections
202 parameters
1 restraint
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.28 e Å⁻³
Δρ_min = −0.27 e Å⁻³

Data collection: CrystalClear (Rigaku, 2007 ▶); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: X-SEED (Barbour, 2001 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811003667/ng5101sup1.cif

e-67-0o552-sup1.cif^{(17.9KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811003667/ng5101Isup2.hkl

e-67-0o552-Isup2.hkl^{(178.6KB, hkl)}

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

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H6⋯N1	0.87 (2)	1.79 (2)	2.653 (2)	173 (3)
N3—H5⋯O1	0.90 (3)	2.08 (3)	2.966 (2)	168 (2)
N3—H1⋯N2ⁱ	0.88 (3)	2.13 (3)	3.006 (2)	173 (2)

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Symmetry code: (i) Inline graphic .

Acknowledgments

This work was supported by the Science and Engineering Research Council of A*STAR (Agency for Science, Technology and Research), Singapore.

supplementary crystallographic information

Comment

An analysis of the crystal structure of pyrimidin-2-amine reveals that it forms a homosynthon (I) involving two N–H···N hydrogen bonds (Scheinbeim and Schempp, 1976). However, when it is cocrystallized with the molecules possessing at least one carboxylic acid group in the structure, it forms a pyrimidin-2-amine–carboxylic acid supramolecular heterosynthon (II) (Fig. 1) involving two hydrogen bonds, namely N–H···O and O–H···N. These strong hydrogen bonds are preferred over potential alternative arrangements and play a significant role in structure-directing (Shan et al., 2002). We have chosen pyrimidin-2-amine and 1-phenylcyclopentane-1-carboxylic acid for cocrystallization experiment as an extension work to our previous study on screening for molecular cocrystals and salts (He et al., 2009).

The crystal structure of the title cocrystal contains one molecule of pyrimidin-2-amine and one molecule of 1-phenylcyclopentane-1-carboxylic acid in the crystallographic asymmetric unit (Fig. 2). The identity of the cocrystal was confirmed by Fourier Transform Infrared (FT—IR) spectrum which showed carboxylic acid O—H stretching band at 3167 cm^-1 and carbonyl stretching band at 1685 cm^-1 (Fig. 3). Two pyrimidin-2-amine molecules that are related by an inversion center form the synthon I involving N–H···O (N···O = 3.006 (2) Å) hydrogen bonds. Two 1-phenylcyclopentane-1-carboxylic acid molecules hydrogen bond to either side of the dimeric motif involving synthon II which is sustained by N–H···O (N···O = 2.966 (2) Å) and O–H···O (O···O = 2.653 (2) Å) hydrogen bonds and forms a four-component supramolecular unit (Fig. 4). These four-component supramolecular units self assemble in the crystal structure via several weak C–H···O interactions (Fig. 5).

Experimental

0.0957 g (1 mmol) of pyrimidin-2-amine (Alfa Aesar, 99%) and 0.1909 g (1 mmol) of 1-phenylcyclopentane-1-carboxylic acid (Alfa Aesar, 98%) and were dissolved into 7.6 ml of ethyl acetate (Fisher Scientific, HPLC). Solution was then filtered through a 0.22µm PTFE filter. Filtered solution was finally sealed with Parafilm and small holes were made to allow solvent to slowly evaporate. The block-shaped crystal (0.44 × 0.44 × 0.22 mm) suitable for single-crystal X-ray diffraction (Rigaku Saturn 70 CCD area detector with Mo K_α radiation = 0.71073 Å at 50 kV and 40 mA) was collected after one day. Fourier Transform Infrared (FT—IR) experiments were performed using Bio-Rad spectrometer (FTS3000MX) to confirm whether the resulting molecular complex is a cocrystal or a salt.