Bis­(3,5-diamino-4H-1,2,4-triazol-1-ium) 3,4-dioxocyclo­butane-1,2-diolate

Hoong-Kun Fun; Wan-Sin Loh; Atim Johnson; Sammer Yousuf; Ededet Eno

doi:10.1107/S160053681300322X

. 2013 Feb 6;69(Pt 3):o353–o354. doi: 10.1107/S160053681300322X

Bis(3,5-diamino-4H-1,2,4-triazol-1-ium) 3,4-dioxocyclobutane-1,2-diolate

Hoong-Kun Fun ^a,^b,^*,^‡, Wan-Sin Loh ^a,^§, Atim Johnson ^c,^d, Sammer Yousuf ^c, Ededet Eno ^d

PMCID: PMC3588514 PMID: 23476545

Abstract

The asymmetric unit of the title compound, 2C₂H₆N₅ ⁺·C₄O₄ ²⁻, contains two 3,5-diamino-4H-1,2,4-triazolium cations and one squarate dianion. The squaric acid molecule donated one H atom to each of the two 3,5-diamino-1,2,4-triazole molecules at their N atoms. The squaric acid dianion has four C—O bonds which are shorter than a normal single C—O bond (1.426 Å) and are slightly longer than a normal C=O bond (1.23 Å), which indicates the degree of electron delocalization in the dianion. In the crystal, the cations and dianions are linked by N—H⋯N and N—H⋯O hydrogen bonds into a three-dimensional network.

Related literature

For background to the acid–base chemistry of squarate acid, see: Mathew et al. (2002 ▶); Frankenbach et al. (1992 ▶); Yeşilel et al. (2008 ▶); Bertolasi et al. (2001 ▶); Correa et al. (2007 ▶). For a related structure, see: Uçar et al. (2004 ▶). For the stability of the temperature controller used for the data collection, see: Cosier & Glazer (1986 ▶). graphic file with name e-69-0o353-scheme1.jpg

Experimental

Crystal data

2C₂H₆N₅ ⁺·C₄O₄ ²⁻
M _r = 312.28
Monoclinic,
a = 15.7186 (2) Å
b = 11.6533 (2) Å
c = 6.8618 (1) Å
β = 91.734 (1)°
V = 1256.32 (3) Å³
Z = 4
Mo Kα radiation
μ = 0.14 mm⁻¹
T = 100 K
0.44 × 0.20 × 0.14 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ▶) T _min = 0.943, T _max = 0.982
19113 measured reflections
4965 independent reflections
3911 reflections with I > 2σ(I)
R _int = 0.028

Refinement

R[F ² > 2σ(F ²)] = 0.040
wR(F ²) = 0.108
S = 1.03
4965 reflections
247 parameters
All H-atom parameters refined
Δρ_max = 0.43 e Å⁻³
Δρ_min = −0.32 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2009 ▶); data reduction: SAINT; 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 and PLATON (Spek, 2009 ▶).

Supplementary Material

Click here for additional data file.^{(25.2KB, cif)}

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S160053681300322X/rz5040sup1.cif

e-69-0o353-sup1.cif^{(25.2KB, cif)}

Click here for additional data file.^{(243.2KB, hkl)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S160053681300322X/rz5040Isup2.hkl

e-69-0o353-Isup2.hkl^{(243.2KB, hkl)}

Click here for additional data file.^{(5.9KB, cml)}

Supplementary material file. DOI: 10.1107/S160053681300322X/rz5040Isup3.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
N1A—H1N1⋯O4ⁱ	0.913 (16)	1.761 (16)	2.6677 (9)	171.3 (15)
N3A—H1N3⋯O4ⁱⁱ	0.937 (15)	1.746 (15)	2.6734 (10)	170.2 (14)
N4A—H1N4⋯O3ⁱ	0.887 (15)	2.003 (15)	2.8877 (10)	175.2 (13)
N4A—H2N4⋯N4B ⁱⁱⁱ	0.904 (15)	2.565 (15)	3.3917 (12)	152.3 (12)
N5A—H1N5⋯N2A ^iv	0.933 (15)	2.105 (15)	3.0167 (11)	165.3 (13)
N5A—H2N5⋯O1ⁱⁱ	0.922 (15)	1.940 (15)	2.8621 (11)	177.7 (14)
N1B—H2N1⋯O2^v	0.874 (15)	1.781 (15)	2.6485 (9)	171.8 (15)
N3B—H2N3⋯O2	0.965 (15)	1.706 (15)	2.6637 (10)	171.2 (14)
N4B—H3N4⋯O1^v	0.920 (14)	2.065 (14)	2.9564 (10)	162.8 (12)
N4B—H4N4⋯O1^vi	0.867 (13)	2.150 (13)	2.9954 (10)	164.9 (12)
N5B—H3N5⋯N2B ^v	0.923 (15)	2.159 (15)	3.0579 (11)	164.3 (12)
N5B—H4N5⋯O3	1.001 (16)	1.832 (15)	2.8293 (10)	174.2 (12)

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

Acknowledgments

HKF and WSL thank the Malaysian Government and Universiti Sains Malaysia (USM) for the Research University Grant (1001/CIPPM813040). WSL also thanks the Malaysian Government and USM for the post of Research Officer under the Research University Grant (1001/PFIZIK/811160). AJ thanks the Academy of Science for the Developing World (TWAS) for the award of a Research and Advanced Training Fellowship and the H. E. J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Pakistan, for providing research facilities. SY thanks the School of Physics, Universiti Sains Malaysia, for providing X-ray diffraction research facilities.

supplementary crystallographic information

Comment

Supramolecularly organized systems with a variety of novel features are widely generated through hydrogen-bonding. Hydrogen-bonded systems generated from organic cations and anions are of special interest since they are likely to show stronger hydrogen bonds than neutral molecules thus enabling the simple acid-base chemistry to tune the donor and acceptor properties of the counter ions (Mathew et al., 2002). Squaric acid (H₂C₄O₄, 3,4-dihydroxy-3-cyclobutene-1,2-dione) has been of much interests because of its cyclic structure and possible aromaticity (Frankenbach et al., 1992; Yeşilel et al., 2008). The molecule possesses a certain degree of electron delocalization, but it is most pronounced in the dianion (Mathew et al. 2002). This property is important in crystal packing (Bertolasi et al., 2001). The squarate dianion does not act like a chelating ligand but rather like a bridge between two or more metal atoms as a mono- or polydentate ligand. The 1,3-bis (monodentate) bridging coordination mode is very useful in generating one dimensional polymeric structures and the dimensionality can be expanded to two-dimensional or three-dimensional arrays using multidentate spacer ligands (Correa et al., 2007). We have been interested in the preparation of metal complexes by organic amines and carboxylic acids. In line with our interests, it was our design to synthesize a squarato-bridged zinc(II) complex. However, our proposed structure was not obtained; instead a new polymeric supramolecular triazolium squarate structure was formed. Herein we present the crystal structure of the new compound.

The asymmetric unit of the title compound, Fig. 1, contains two 3,5-diamino-4H-1,2,4-triazolium cations (C5/C6/N1–N5) and one squarate dianion (C1–C4/O1–O4). The squaric acid molecule donates one proton to each of the 3,5-diamino-1,2,4-triazole at N3A and N3B atoms which result in the formation of the 3,5-diamino-4H-1,2,4-triazolium squarate salt. The squaric acid dianion has four C–O bonds [C1—O1 = 1.2599 (10) Å, C2—O2 = 1.2608 (10) Å, C3—O3 = 1.2490 (10) Å, C4—O4 = 1.2622 (10) Å] which are shorter than normal single C—O bond (1.426 Å). These bonds, however, are slightly longer than normal C═O bond (1.23 Å). These bond lengths are indicative of the degree of electron delocalization in the dianion (Mathew et al. 2002; Bertolasi et al., 2001; Uçar et al., 2004).

In the crystal packing (Fig. 2), the structure of the compound is stabilized by intermolecular N—H···N and N—H···O hydrogen bonds (Table 1) into a three dimensional network.

Experimental

Zinc chloride (1 mmol, 0.136 g) and 3,5-diamino-1,2,4-triazole (1 mmol, 0.099 g) were dissolved in 10 ml of distilled water. The solution was heated gently for 5 minutes, followed by drop-wise addition of an aqueous solution of squaric acid (0.057 g, 0.5 mmol) dissolved in 5 ml of hot water. The mixture was heated on a steam bath for 15 minutes and filtered while hot. The filtrate was allowed to crystallize at ambient temperature. The compound crystallized out after two weeks. CHN-analysis: found, C, 30.79; H, 3.82; N, 44.89; calcd. for C₈H₁₂N₁₀O₄: C, 30.76; H, 3.85; N, 44.93.