Propane-1,2-diaminium bis­(4-meth­oxy­benzoate)

Zong-Ling Ru

doi:10.1107/S1600536811023968

. 2011 Jun 25;67(Pt 7):o1817. doi: 10.1107/S1600536811023968

Propane-1,2-diaminium bis(4-methoxybenzoate)

Zong-Ling Ru ^a,^*

PMCID: PMC3151787 PMID: 21837186

Abstract

The asymmetric unit of the title salt, C₃H₁₂N₂ ²⁺·2C₈H₇O₃ ⁻, contains two 4-methoxybenzoate anions and one propane-1,2-diaminium cation. All the amino H atoms of the cation are involved in N—H⋯O hydrogen bonds with the carboxylate O atoms of the anions.

Related literature

For related amide-acid co-crystal compounds, see: Almarsson & Zaworotko (2004 ▶); Blagden et al. (2008 ▶); Vishweshwar et al. (2006 ▶); Kapildev et al. (2011 ▶); Schultheiss & Newman (2009 ▶).

Experimental

Crystal data

C₃H₁₂N₂ ²⁺·2C₈H₇O₃ ⁻
M _r = 378.42
Monoclinic,
a = 13.847 (3) Å
b = 11.296 (2) Å
c = 12.893 (3) Å
β = 92.38 (3)°
V = 2014.8 (7) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 298 K
0.30 × 0.05 × 0.05 mm

Data collection

Rigaku Mercury2 diffractometer
20478 measured reflections
4611 independent reflections
2264 reflections with I > 2σ(I)
R _int = 0.116

Refinement

R[F ² > 2σ(F ²)] = 0.073
wR(F ²) = 0.194
S = 1.03
4611 reflections
244 parameters
H-atom parameters constrained
Δρ_max = 0.16 e Å⁻³
Δρ_min = −0.26 e Å⁻³

Data collection: CrystalClear (Rigaku, 2005 ▶); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536811023968/xu5245sup1.cif

e-67-o1817-sup1.cif^{(25.8KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811023968/xu5245Isup2.hkl

e-67-o1817-Isup2.hkl^{(225.9KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811023968/xu5245Isup3.cml

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
N1—H1A⋯O4ⁱ	0.90	1.82	2.696 (3)	162
N1—H1B⋯O1	0.90	1.92	2.791 (3)	162
N1—H1C⋯O1ⁱⁱ	0.90	1.89	2.777 (3)	167
N2—H2A⋯O5ⁱⁱⁱ	0.90	1.82	2.718 (3)	173
N2—H2B⋯O4^iv	0.90	2.03	2.917 (3)	170
N2—H2C⋯O2ⁱⁱ	0.90	1.81	2.703 (3)	1670

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) .

Acknowledgments

This work was supported by the start-up fund of Anyang Institute of Technology, China.

supplementary crystallographic information

Comment

Molecular cocrystals are becoming increasingly important within the pharmaceutical industry as an alternative source of new solid crystalline materials with the potential to provide optimal physical properties whilst retaining the chemical properties of the cocrystal components (Almarsson & Zaworotko, 2004; Blagden et al., 2008; Vishweshwar et al., 2006). Physicochemical properties such as the melting point, stability and solubility of an active pharmaceutical ingredient can be tuned through cocrystal formulation (Kapildev et al., 2011; Schultheiss & Newman, 2009). Cocrystal synthesis often relies on the acid-amide H-bonds interactions. Herein, we report the crystal structure of the title compound, propane-1,2-diaminium di-4-methoxybenzoate.

The asymmetric unit is composed of two 4-methoxybenzoate anions and one propane-1,2-diaminium cation (Fig. 1). Both the amine N atoms were protonated. And the carboxyl groups were deprotonated. The geometric parameters of the title compound are in the normal range.

In the crystal structure, all the amino H atoms are involved in N—H···O hydrogen bonds with the carboxyl O atoms (Table 1 and Fig. 2).

Experimental

A mixture of R-propane-1,2-diamine (1.0 mmol), 4-methoxybenzoic acid (2.0 mmol) and 20 ml ethanol were added into a 50 ml flask and refluxed for 5 h, then cooled and filtrated. The solution was evaporated slowly in the air. Colorless block crystals suitable for X-ray analysis were obtained after one week. The R-propane-1,2-diamine turned into racemic amine in the heating process.