l-Histidinium dipicrate dihydrate

M Sethuram; M V Rajasekharan; M Dhandapani; G Amirthaganesan; M NizamMohideen

doi:10.1107/S1600536813013949

. 2013 May 25;69(Pt 6):o957–o958. doi: 10.1107/S1600536813013949

l-Histidinium dipicrate dihydrate

M Sethuram ^a, M V Rajasekharan ^b, M Dhandapani ^a, G Amirthaganesan ^a, M NizamMohideen ^c,^*

PMCID: PMC3685097 PMID: 23795116

Abstract

In the title molecular salt, C₆H₁₁N₃O₂ ²⁺·2C₆H₂N₃O₇ ⁻·2H₂O, the histidine molecule exists as a histidinium dication, being protonated at the N atom of the imidazole ring. The charges are balanced by two picrate anions and the compound crystallizes as a dihydrate. In the crystal, the components are linked via N—H⋯O and O—H⋯O hydrogen bonds and weak C—H⋯O interactions, forming a three-dimensional supermolecular structure.

Related literature

For the role of hydrogen bonding in the construction of supramolecular structures, see: Braga et al. (2004 ▶); Harrowfield et al. (1995 ▶). For picrates of biologically important molecules, see: Harrison et al. (2007 ▶); Swamy et al. (2007 ▶); Bibal et al. (2003 ▶); Olsher et al. (1996 ▶). For bond angles in related structures, see: Yang et al. (2001 ▶). graphic file with name e-69-0o957-scheme1.jpg

Experimental

Crystal data

C₆H₁₁N₃O₂ ²⁺·2C₆H₂N₃O₇ ⁻·2H₂O
M _r = 649.42
Monoclinic,
a = 6.6060 (4) Å
b = 25.7003 (13) Å
c = 7.9627 (5) Å
β = 107.532 (7)°
V = 1289.08 (13) Å³
Z = 2
Mo Kα radiation
μ = 0.15 mm⁻¹
T = 293 K
0.20 × 0.15 × 0.10 mm

Data collection

Bruker Kappa APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2004 ▶) T _min = 0.970, T _max = 0.985
5817 measured reflections
2982 independent reflections
2560 reflections with I > 2σ(I)
R _int = 0.020

Refinement

R[F ² > 2σ(F ²)] = 0.039
wR(F ²) = 0.088
S = 1.09
2982 reflections
439 parameters
7 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.21 e Å⁻³
Δρ_min = −0.18 e Å⁻³

Data collection: APEX2 (Bruker, 2004 ▶); cell refinement: APEX2 and SAINT (Bruker, 2004 ▶); data reduction: SAINT and XPREP (Bruker, 2004 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012 ▶) and Mercury (Macrae et al., 2008 ▶); software used to prepare material for publication: WinGX (Farrugia, 2012 ▶) and PLATON (Spek, 2009 ▶).

Supplementary Material

Click here for additional data file.^{(33.6KB, cif)}

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536813013949/su2602sup1.cif

e-69-0o957-sup1.cif^{(33.6KB, cif)}

Click here for additional data file.^{(143.3KB, hkl)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536813013949/su2602Isup2.hkl

e-69-0o957-Isup2.hkl^{(143.3KB, hkl)}

Click here for additional data file.^{(13.5KB, cml)}

Supplementary material file. DOI: 10.1107/S1600536813013949/su2602Isup3.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⋯O10	0.89	2.19	2.909 (3)	138
N1—H1A⋯O12	0.89	2.11	2.841 (4)	139
N1—H1B⋯O18W	0.89	1.85	2.700 (5)	158
N1—H1C⋯O15ⁱ	0.89	2.16	3.007 (4)	159
N2—H2B⋯O10	0.91 (5)	1.86 (5)	2.709 (4)	154 (4)
N2—H2B⋯O16	0.91 (5)	2.49 (4)	3.125 (4)	128 (3)
N3—H3⋯O9ⁱⁱ	0.86	2.56	2.992 (5)	112
N3—H3⋯O14ⁱⁱ	0.86	2.25	3.077 (4)	160
O2—H2⋯O3ⁱⁱⁱ	0.82	1.86	2.657 (3)	165
O17W—H17A⋯O5^iv	0.84 (2)	2.27 (3)	3.082 (4)	162 (9)
O17W—H17B⋯O3	0.84 (2)	2.14 (8)	2.864 (4)	144 (12)
O18W—H18A⋯O17W ^v	0.83 (2)	1.83 (2)	2.664 (5)	176 (5)
O18W—H18B⋯O7	0.83 (2)	2.32 (4)	3.005 (5)	140 (6)
C3—H3B⋯O10	0.97	2.59	3.210 (4)	122
C9—H9⋯O8^vi	0.93	2.40	3.177 (4)	141
C17—H17⋯O11^iv	0.93	2.36	3.177 (3)	147

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

Acknowledgments

MS thanks the UGC Networking Centre, School of Chemistry, University of Hyderabad, India, for the award of a Visiting Research Fellowship to use the facilities at the School, which the authors also thank for access to the X-ray diffraction equipment.

supplementary crystallographic information

Comment

Intermolecular and inter-ionic hydrogen bonding interactions, which are not only the strongest of the noncovalent interactions but also highly directional, play an important role in constructing supramolecular structures (Braga et al., 2004). Picrate is generally used as an accompanying ion in many systems involving extraction and transport of metal ions to improve the extractability (Bibal et al., 2003). Picrate interacts as a monodentate, bidentate and tridentate ligand (Olsher et al., 1996). Furthermore, picrate is a penta-dentate ligand when it coordinates with cation by chelating pairs of oxygen atoms from p-nitro groups of adjacent picrates, and with successive cations linking the array into a two or three-dimensional network (Harrowfield et al., 1995) and picrates of biologically important molecules (Harrison et al., 2007; Swamy et al., 2007). We have prepared a new picrate of L-Histidinium hydrate and its crystal structure is reported herein.

The asymmetric unit of the title compound, Fig. 1, contains an L-histidinium cation, two picrate anions and two water molecules. The histidine molecule exists as an histidinium ion due to the protonation at the N atom of the imidazole ring. The charges are equilibrated by two picrate anions and crystallizes as a dihydrate. The imidazole ring (N2/N3/C4/C5/C6) makes a dihedral angle of 5.0 (2) and 4.9 (2)° with the benzene rings (C7—C12 and C13—C18), respectively, of the picrate anions.

The picrate anions adopt the keto form with C7—O3 and C13—O10 bond distance of 1.261 (4) and 1.249 (4) Å, C7—C8, C7—C12, C13—C14 and C13—C18 bond distance of 1.445 (4), 1.444 (4), 1.451 (4) and 1.450 (4) Å, respectively, which is longer than the other C—C bond lengths (between 1.374 (5) to 1.460 (4) Å) in the benzene ring. The bond angles C12—C7—C8 and C14—C13—C18 is 111.3 (3) and 110.6 (3)°, respectively, which is the case in some picrate complexes, while the corresponding bond angle of picric acid is 116.4 (5)° [Yang et al., 2001]. In the picrate anion the depronated phenolate oxygen atom deviates slightly from the plane of the benzene ring (torsion angle O3-C7-C8-C9 = -175.4 (3) ° and O10-C13-C14-C15 = 178.2 (3)°). The twist angles between the benzene rings (C7—C12 and C13—C18) and the ortho nitro groups (N4, N6, N7 and N9) are 41.5 (2), 32.4 (2), 32.2 (2) and 34.8 (2), respectively. The para-positioned nitro groups are twisted by 3.4 (2)° (N5) and 5.8 (2)° (N8), and are most likely influenced by a weak hydrogen bond interaction (O18—H18B···O7). The picrate ions are stacked head-to-tail, presumably as a result of charge-transfer interactions.

In the crystal the cation, the picrate anions and the water molecules of crystallization are involved in N—H···O and O—H···O hydrogen bonds and week C—H···O interactions, to form a three-dimensional supramolecular network (Table 1 and Fig. 2).

Experimental

1:2 stoichiometric proportions of analar grades L-histidine and picric acid (E-Merck) were dissolved in a triply distilled water and ethanol mixture and the two solutions were thoroughly mixed together using mechanical stirrer for about three hours. The clear yellow solution obtained was filtered off to get the crude material. The material was re-dissolved in a water-ethanol solvent mixture and kept aside without any mechanical movement for crystal growth in a dust free environment. Bright yellowish crystals that formed in 5 days were collected carefully from the mother liquor. Several re-crystallizations were done to get ultra pure crystals. The yield in the reaction was ca. 60%. Analysis calc. for C₁₈H₁₈N₉O₁₈: C: 33.34, H: 2.79, N: 19.44 %; Found: C: 33.21, H: 3.74, N: 19.60%.