N,N-Dimethylpyridin-4-aminium 1-phenyl­cyclo­pentane-1-carboxyl­ate monohydrate

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

doi:10.1107/S1600536811015200

. 2011 Apr 29;67(Pt 5):o1227. doi: 10.1107/S1600536811015200

N,N-Dimethylpyridin-4-aminium 1-phenylcyclopentane-1-carboxylate monohydrate

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

PMCID: PMC3089254 PMID: 21754525

Abstract

The cation of the title salt, C₇H₁₁N₂ ⁺·C₁₂H₁₃O₂ ⁻·H₂O, is planar (r.m.s. deviation = 0.0184 Å). In the crystal, the cation, anion and water molecule are linked by O—H⋯O and N—H⋯O hydrogen bonds, forming a chain running along the a axis.

Related literature

For the structure of 4-dimethylaminopyridine, see: Ohms & Guth (1984 ▶). For the structure of 1-phenylcyclopentane-1-carboxylic acid, see: Margulis (1975 ▶). For recent molecular co-crystals and salts of 4-dimethylaminopyridine, see: Dastidar et al. (1993 ▶). For recent molecular co-crystals of 1-phenylcyclopentane-1-carboxylic acid, see: He et al. (2010 ▶, 2011 ▶). For comparative bond dimensions in pyridinium carboxylates, see: Kumar et al. (2009 ▶).

Experimental

Crystal data

C₇H₁₁N₂ ⁺·C₁₂H₁₃O₂ ⁻·H₂O
M _r = 330.42
Monoclinic,
a = 6.1666 (12) Å
b = 18.206 (4) Å
c = 15.702 (3) Å
β = 97.33 (3)°
V = 1748.4 (6) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 110 K
0.44 × 0.33 × 0.22 mm

Data collection

Bruker APEXII diffractometer
Absorption correction: multi-scan (Blessing, 1995 ▶) T _min = 0.964, T _max = 0.982
12519 measured reflections
4233 independent reflections
3945 reflections with I > 2σ(I)
R _int = 0.017

Refinement

R[F ² > 2σ(F ²)] = 0.051
wR(F ²) = 0.139
S = 1.13
4233 reflections
231 parameters
3 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.23 e Å⁻³
Δρ_min = −0.21 e Å⁻³

Data collection: APEX2 (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: X-SEED (Barbour, 2001 ▶); software used to prepare material for publication: SHELXTL (Sheldrick, 2008 ▶) and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811015200/ng5153sup1.cif

e-67-o1227-sup1.cif^{(19.3KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811015200/ng5153Isup2.hkl

e-67-o1227-Isup2.hkl^{(207.5KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811015200/ng5153Isup3.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—H7⋯O2	0.94 (2)	1.72 (2)	2.6458 (15)	168 (2)
O3—H3⋯O2	0.87 (2)	1.93 (2)	2.7935 (14)	167 (2)
O3—H6⋯O1ⁱ	0.87 (2)	1.90 (2)	2.7634 (15)	169 (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

Substituted pyridines such as 4-dimethylaminopyridine was found to form binary salt hydrate with l-tartaric acid (Dastidar et al., 1993). The authors have shown that this molecular complex possesses high nonlinear optical (NLO) effects, viz. second harmonic generation (SHG) in the crystalline state. In our previous work, we have demonstrated the formation of a salt and a cocrystal of a substituted pyridine, 2-aminopyridine, with 1-phenylcyclopropane-1-carboxylic acid and 1-phenylcyclopentane-1-carboxylic acid, respectively (He et al., 2010; He et al., 2011). Here we have selected 4-dimethylaminopyridine and 1-phenylcyclopentane-1-carboxylic acid as a model molecular pair.

The crystal structure of the title salt hydrate contains each one molecule of 4-dimethylaminopyridinium ion, 1-phenylcyclopentane-1-carboxylate ion, and water (Fig. 1). The title molecular complex is a salt rather than a cocrystal is evident by the proton transfer from the carboxylic acid to the pyridine nitrogen of the 4-dimethylaminopyridine, which was located in the difference Fourier map during the refinement cycles. Furthermore, the C—O/C=O bond distances (1.2412 (16) Å and 1.2700 (16) Å) and C—N—C angle of pyridine group (119.93 (12)°) are in well agreement with the corresponding distances/angles that are generally observed for a carboxylic acid-pyridine salts (Kumar et al., 2009). In the crystal structure, the translation related 1-phenylcyclopentane-1-carboxylate ions are connected via water molecules involving O—H···O hydrogen bonds (Table 1) and generate infinite hydrogen bonded chains along the crystallographic a-axis (Fig. 2). The 4-dimethylaminopyridinium ion hydrogen bonded to one of the O atoms of the carboxylate ion via N—H···O hydrogen bond (Fig. 2). The hydrogen bonded chians close pack to build up the overall crystal structure (Fig. 3). A TGA experiment indicates an initial weight loss (ca 6%) upon heating (Fig. 4). This number matches with the water content in the title salt hydrate, implying that the resulting molecular complex is indeed a hydrate.

Experimental

0.1224 g (1 mmol) of 4-dimethylaminopyridine (Alfa Aesar, 99%) and 0.1902 g (1 mmol) of 1-phenylcyclopentane-1-carboxylic acid (Alfa Aesar, 98%) and were dissolved into 7 ml of acetonitrile/water (90/10 v/v%) (acetonitrile, Fisher Scientific, HPLC; deionized water). Solution was then filtered through a 0.22 µm PTFE filter. Filtered solution was finally sealed with Parafilm and small holes were made to allow solvent to slowly evaporate. The colorless block-shaped crystal (0.44 × 0.33 × 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 three day. TGA-DSC experiment of the resulting crystals was run using a TA Instrument SDT-TGA (SDT2960) at a ramping rate of 10 °C/min to 1000 °C.