Bis(4-meth­oxy­benzyl­ammonium) dihydrogen diphosphate

Adel Elboulali; Samah Akriche; Salem S Al-Deyab; Mohamed Rzaigui

doi:10.1107/S1600536812051616

. 2013 Jan 9;69(Pt 2):o213–o214. doi: 10.1107/S1600536812051616

Bis(4-methoxybenzylammonium) dihydrogen diphosphate

Adel Elboulali ^a, Samah Akriche ^a,^*, Salem S Al-Deyab ^b, Mohamed Rzaigui ^a

PMCID: PMC3569749 PMID: 23424495

Abstract

In the title compound, 2C₈H₁₂NO⁺·H₂P₂O₇ ²⁻, the linked PO₄ groups of the diphosphate anion are almost eclipsed and the P—O—P angle is 134.45 (7)°. In the crystal, infinite ribbons of H₂P₂O₇ ²⁻ anions propagate in [100], being linked by strong O—H⋯O hydrogen bonds. The 4-methoxybenzylammonium cations bond to the diphosphate chains by N—H⋯O and C—H⋯O links, and are themselves linked by C—H⋯π interactions.

Related literature

For background to diphosphates, see: Ballarini et al. (2006 ▶); For intermolecular interactions, see: Brown (1976 ▶); Tiekink & Zukerman-Schpector (2012 ▶). For a related structure, see: Ahmed et al. (2006 ▶).

Experimental

Crystal data

2C₈H₁₂NO⁺·H₂P₂O₇ ²⁻
M _r = 452.33
Triclinic,
a = 9.184 (3) Å
b = 6.737 (4) Å
c = 17.066 (2) Å
α = 97.61 (2)°
β = 91.39 (4)°
γ = 85.72 (3)°
V = 1043.6 (7) Å³
Z = 2
Ag Kα radiation
λ = 0.56087 Å
μ = 0.14 mm⁻¹
T = 296 K
0.30 × 0.25 × 0.17 mm

Data collection

Enraf–Nonius CAD-4 diffractometer
12631 measured reflections
10225 independent reflections
5553 reflections with I > 2σ(I)
R _int = 0.026
2 standard reflections every 120 min intensity decay: none

Refinement

R[F ² > 2σ(F ²)] = 0.055
wR(F ²) = 0.143
S = 0.98
10225 reflections
268 parameters
H-atom parameters constrained
Δρ_max = 0.38 e Å⁻³
Δρ_min = −0.51 e Å⁻³

Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994 ▶); cell refinement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms & Wocadlo, 1995 ▶); program(s) used to solve structure: SHELXS86 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 2012 ▶) and DIAMOND (Brandenburg & Putz, 2005 ▶); software used to prepare material for publication: WinGX (Farrugia, 2012 ▶).

Supplementary Material

Click here for additional data file.^{(21.2KB, cif)}

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812051616/hb7003sup1.cif

e-69-0o213-sup1.cif^{(21.2KB, cif)}

Click here for additional data file.^{(489.9KB, hkl)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812051616/hb7003Isup2.hkl

e-69-0o213-Isup2.hkl^{(489.9KB, hkl)}

Click here for additional data file.^{(8.1KB, cml)}

Supplementary material file. DOI: 10.1107/S1600536812051616/hb7003Isup3.cml

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

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

Cg1 and Cg2 are the centroids of the C2–C7 and C10–C15 rings, respectively.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1⋯O6ⁱ	0.82	1.82	2.6347 (18)	176
O5—H5⋯O2ⁱⁱ	0.82	1.75	2.5535 (18)	164
N1—H1A⋯O3ⁱⁱⁱ	0.89	2.09	2.941 (2)	160
N1—H1B⋯O3ⁱⁱ	0.89	1.97	2.857 (2)	172
N1—H1C⋯O2	0.89	2.03	2.915 (2)	173
N2—H2B⋯O6	0.89	2.35	3.156 (2)	151
N2—H2A⋯O6^iv	0.89	1.89	2.734 (2)	157
N2—H2B⋯O4	0.89	2.38	3.150 (2)	145
N2—H2C⋯O7ⁱ	0.89	1.85	2.724 (2)	168
C1—H1D⋯O7ⁱⁱ	0.97	2.49	3.242 (3)	134
C7—H7⋯O2	0.93	2.54	3.195 (2)	127
C16—H16C⋯Cg1^v	0.96	2.93	3.73 (7)	142
C8—H8A⋯Cg2	0.96	2.97	3.72 (7)	137
C1—H1D⋯Cg2^vi	0.97	2.90	3.54 (7)	124

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

Acknowledgments

This work was supported by the Tunisian Carthage University and the Deanship of Scientific Research at King Saud University through the Research Group Project No. RGP-VPP-089.

supplementary crystallographic information

Comment

Diphosphates are known to play an important role as catalysts (Ballarini et al., 2006). As part of our studies in this area, we report the synthesis and the crystal structure of the title compound, (I) (Fig. 1).

In this structure, [H₂P₂O₇]^2- species are connected by means of strong hydrogen bonds of type O—H···O with O···O distances less than 2.7 Å, limit as recommended by Brown (1976). This infinite sequence forms ribbons extending along a axis.

Except the H atoms, the P₂O₇ group, has an eclipsed conformation evidenced by the torsion angle O3—P1—P2—O7 = -1.5°. As usually observed for diphosphate groups (Ahmed et al., 2006), there are three different types of P—O distances, the longest one corresponds to the bridging oxygen atom with average value d(P—O4) = 1,608 (1) Å, the intermediate ones are the P—OH bonding [d(P1—O1) = 1.566 (1) Å, d(P2—O5) = 1.552 (1) Å], whereas the shortest ones, spreading between 1.474 (1) Å and 1.503 (1) Å are related to the external oxygen atoms. The average values of the P—O distances and O—P—O angles are 1,536 (1) Å and 109,24 (7)° respectively.

The organic cations linked by C–H···π interaction (Tiekink and Zukerman-Schpector, 2012) into chains along a axis, are anchored onto successive inorganic ribbons [H₂P₂O₇]_n^2n- through hydrogen bonds of type N—H···O and C—H···O with donor-acceptor distances varying between 2.724 (2) Å and 3.156 (2) Å.

It should be noticed that another diphosphate with the same organic molecule, [4-(OCH₃)C₆H₄CH₂NH₃]₄P₂O₇.6H₂O, has been reported by Ahmed et al. (2006). Structure of this hydrated diphosphate is different from that of the non-hydrated one described here. This difference may be explained by the role of water of crystallization as directing structure agent.

Experimental

An aqueous solution of diphosphoric acid H₄P₂O₇ was first obtained by passing a solution of Na₄P₂O₇ (3 g, 11.2 mmol), through an ion exchange resin (Amberlite IR 120) in its H-state. To 20 ml of this acidic solution (1.5 mmol) cooled to 5°C, a solution of 4-methoxybenzylamine (3 mmol) in ethanol (3 mL),was added drop by drop with slow stirring. The obtained solution was slowly evapored at room temperature until crystallization of colourless prisms.