Hexa­kis­(propyl­ammonium) benzene-1,2,4,5-tetra­carboxyl­ate 2,5-dicarb­oxy­benzene-1,4-carboxyl­ate tetra­hydrate

Sanaz Khorasani; Manuel A Fernandes

doi:10.1107/S1600536812036501

. 2012 Aug 31;68(Pt 9):o2807. doi: 10.1107/S1600536812036501

Hexakis(propylammonium) benzene-1,2,4,5-tetracarboxylate 2,5-dicarboxybenzene-1,4-carboxylate tetrahydrate

Sanaz Khorasani ^a, Manuel A Fernandes ^a,^*

PMCID: PMC3435833 PMID: 22969679

Abstract

The title organic salt, 6C₃H₁₀N⁺·C₁₀H₂O₈ ⁴⁻·C₁₀H₄O₈ ²⁻·4H₂O, contains seven independent entities in the asymmetric unit which comprises three propylammonium cations, two water molecules, half a 2,5-dicarboxybenzene-1,4-carboxylate dianion (H₂btc²⁻) and half a benzene-1,2,4,5-tetracarboxylate tetraanion (btc⁴⁻), the latter two anions being located about centres of inversion. One of the water molecules is disordered over two positions in a 0.55 (2):0.45 (2) ratio. The combination of molecular ions and water molecules results in an extensive and complex three-dimensional network of hydrogen bonds, the network being made up of nine unique N—H⋯O interactions between the ammonium cations and the anions, as well as four unique O—H⋯O interactions between the water molecules and the anions.

Related literature

For studies involving hydrogen-bonding interactions, see: Pimentel & McClellan (1960 ▶); Lemmerer (2011 ▶); Arora & Pedireddi (2003 ▶); Biradha & Zaworotko (1998 ▶). For graph-set motifs in crystal structures, see: Etter et al. (1990 ▶); Bernstein et al. (1995 ▶).

Experimental

Crystal data

6C₃H₁₀N⁺·C₁₀H₂O₈ ⁴⁻·C₁₀H₄O₈ ²⁻·4H₂O
M _r = 935.03
Triclinic,
a = 9.9826 (2) Å
b = 11.0994 (2) Å
c = 12.4453 (2) Å
α = 107.461 (1)°
β = 90.062 (1)°
γ = 105.721 (1)°
V = 1261.10 (4) Å³
Z = 1
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 173 K
0.55 × 0.33 × 0.06 mm

Data collection

Bruker APEXII CCD diffractometer
41269 measured reflections
6092 independent reflections
4741 reflections with I > 2σ(I)
R _int = 0.064

Refinement

R[F ² > 2σ(F ²)] = 0.040
wR(F ²) = 0.118
S = 1.10
6092 reflections
359 parameters
36 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.40 e Å⁻³
Δρ_min = −0.21 e Å⁻³

Data collection: APEX2 (Bruker, 2005 ▶); cell refinement: SAINT (Bruker, 2005 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: PLATON (Spek, 2009 ▶) and SCHAKAL99 (Keller, 1999 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶) and PLATON.

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536812036501/bh2430sup1.cif

e-68-o2807-sup1.cif^{(31.4KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812036501/bh2430Isup2.hkl

e-68-o2807-Isup2.hkl^{(292.2KB, 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
N1C—H1C⋯O1W	0.93 (1)	1.93 (1)	2.8293 (14)	162 (1)
N1D—H1F⋯O1B	0.98 (1)	1.77 (1)	2.7387 (14)	172 (1)
N1E—H1I⋯O4B	0.95 (1)	1.87 (1)	2.8197 (13)	179 (1)
N1C—H1B⋯O1B ⁱ	0.96 (1)	1.92 (1)	2.8598 (13)	167 (1)
N1C—H1D⋯O2B ⁱⁱ	0.94 (1)	1.80 (1)	2.7269 (13)	171 (1)
N1D—H1G⋯O3A ⁱⁱⁱ	0.95 (1)	1.94 (1)	2.8725 (14)	167 (2)
N1D—H1E⋯O4A ^iv	0.98 (1)	1.79 (1)	2.7642 (14)	179 (2)
N1E—H1H⋯O2A ^iv	0.98 (1)	1.91 (1)	2.8493 (14)	159 (2)
N1E—H1J⋯O3B ⁱⁱⁱ	0.97 (1)	1.75 (1)	2.7170 (13)	174 (1)
O1W—H1WB⋯O3A ⁱⁱⁱ	0.880 (19)	1.94 (2)	2.8107 (14)	169.2 (17)
O1W—H1WA⋯O3B	0.958 (19)	1.796 (19)	2.7421 (14)	169.1 (16)
O1A—H1A⋯O2WB ^v	1.00 (2)	1.54 (2)	2.513 (4)	163.1 (19)
O1A—H1A⋯O2WA ^v	1.00 (2)	1.62 (2)	2.598 (5)	168.4 (19)

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

Acknowledgments

This work was supported by the National Research Foundation, Pretoria (NRF, GUN 77122) and the University of the Witwatersrand.

supplementary crystallographic information

Comment

Intramolecular and intermolecular hydrogen bonding is of great importance in chemical and biological systems. In the crystal engineering field, hydrogen bonding plays an important role to organize molecules and assemble them to create supramolecules and control their dimensions in one-dimensional, two-dimensional, or three-dimensional networks (Lemmerer, 2011; Pimentel & McClellan, 1960; Arora & Pedireddi, 2003; Biradha & Zaworotko, 1998).

The title salt complex (Fig. 1) crystallizes in the centrosymmetric triclinic space group P-1 and contains seven independent entities per asymmetric unit: half a 2,5-dicarboxybenzene-1,4-carboxylate dianion (H₂btc^2-; molecule A), half a benzene-1,2,4,5-tetracarboxylate tetraanion (btc^4-; molecule B), three propylammonium cations (molecules C, D and E), and two water molecules (Fig. 1). Both aromatic anions lie about inversion centres located at the centroids of the aromatic rings. One of the water molecules is disordered over two positions in a 0.55 (2):0.45 (2) ratio.

The crystal structure contains a very extensive hydrogen bonded network based on O—H···O and N—H···O interactions. Several of these involve water molecules. Water molecule O1W accepts a hydrogen from N1C located on propylammonium cation C (N1C—H1C···O1W), and donates H atoms to both aromatic anions (molecules A and B). It is therefore involved in hydrogen bonding to an ammonium cation and two aromatic anions (Fig. 2). Figure 3 shows the hydrogen bonding between the O2WA water molecule and adjacent aromatic anions. In this case the disordered water molecule only forms intermolecular hydrogen bonds with the aromatic anions as both donor and acceptor. Hydrogen bonds involving O2WA as hydrogen donor consist of O2WA—H2WA···O4B and O2WA—H2WB···O3A, and as acceptor consists of O1A—H1A···O2WA (Table 1). The combination of two O2WA water molecules and the two aromatic anions (molecules A and B) forms a hydrogen bonded ring described by the graph set R⁴₄(18) (Etter et al., 1990; Bernstein et al., 1995). This extends as a chain of rings along the a axis. There are no intramolecular hydrogen bonds in this structure due to the syn orientation of the carboxyl hydrogen atoms. Each of the three independent propylammonium cations (molecules C, D, and E) donate three hydrogen atoms to various molecules and hence do not participate in hydrogen bond interactions with each other. Cations D and E hydrogen bond exclusively to the two aromatic anions: cation D hydrogen bonds to one B tetraanion and two A dianions, while cation E hydrogen bonds to one A dianion and two B tetraanions. The environment around propylammonium cation C is different from D and E in that it is involved in hydrogen bonding to a water molecule in addition to two B tetraanions.

Experimental

The title organic salt was synthesized by reacting propylamine (0.27 g) with pyromellitic dianhydride (0.50 g) in the presence of THF (5 ml; not anhydrous) as a solvent, at room temperature – the presence of water resulting in ring opening of the pyromellitic dianhydride and subsequent salt formation. The solid was filtered and recrystallized in methanol, yielding colourless crystals suitable for analysis by X-ray diffraction.