2-Amino-5-chloro­pyridinium cis-diaqua­dioxalatochromate(III) sesquihydrate

Ichraf Chérif; Jawher Abdelhak; Mohamed Faouzi Zid; Ahmed Driss

doi:10.1107/S1600536812023392

. 2012 May 26;68(Pt 6):m824–m825. doi: 10.1107/S1600536812023392

2-Amino-5-chloropyridinium cis-diaquadioxalatochromate(III) sesquihydrate

Ichraf Chérif ^a,^*, Jawher Abdelhak ^a, Mohamed Faouzi Zid ^a, Ahmed Driss ^a

PMCID: PMC3379145 PMID: 22719366

Abstract

In the crystal structure of the title compound, (C₅H₆ClN₂)[Cr(C₂O₄)₂(H₂O)₂]·1.5H₂O, the Cr^III atom adopts a distorted octahedral geometry being coordinated by two O atoms of two cis water molecules and four O atoms from two chelating oxalate dianions. The cis-diaquadioxalatochromate(III) anions, 2-amino-5-chloropyridinium cations and uncoordinated water molecules are linked into a three-dimensional supramolecular array by O—H⋯O and N—H⋯O hydrogen-bonding interactions. One of the two independent lattice water molecules is situated on a twofold rotation axis.

Related literature

For structural characterization of salts containing the [Cr(C₂O₄)₂(H₂O)₂]⁻ anion with various cations see: Bélombé et al. (2009 ▶); Nenwa et al. (2010 ▶); Chérif et al. (2011 ▶). For the building of hybrid supramolecular networks, see: Zhang et al. (2000 ▶); Paraschiv et al. (2007 ▶). For discussion of hydrogen bonding, see: Blessing (1986 ▶); Brown (1976 ▶). graphic file with name e-68-0m824-scheme1.jpg

Experimental

Crystal data

(C₅H₆ClN₂)[Cr(C₂O₄)₂(H₂O)₂]·1.5H₂O
M _r = 420.66
Orthorhombic,
a = 11.376 (2) Å
b = 53.041 (3) Å
c = 10.413 (2) Å
V = 6283.1 (17) Å³
Z = 16
Mo Kα radiation
μ = 0.96 mm⁻¹
T = 298 K
0.42 × 0.32 × 0.13 mm

Data collection

Enraf–Nonius CAD-4 diffractometer
Absorption correction: ψ scan (North et al., 1968 ▶) T _min = 0.792, T _max = 0.882
3854 measured reflections
3414 independent reflections
3180 reflections with I > 2σ(I)
R _int = 0.022
2 standard reflections every 120 min intensity decay: 5%

Refinement

R[F ² > 2σ(F ²)] = 0.029
wR(F ²) = 0.074
S = 1.07
3414 reflections
243 parameters
8 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.30 e Å⁻³
Δρ_min = −0.31 e Å⁻³
Absolute structure: Flack (1983 ▶), 1608 Friedel pairs
Flack parameter: 0.000 (18)

Data collection: CAD-4 EXPRESS (Duisenberg, 1992 ▶; Macíček & Yordanov, 1992 ▶); cell refinement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms & Wocadlo, 1995 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: DIAMOND (Brandenburg, 1998 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812023392/kp2416sup1.cif

e-68-0m824-sup1.cif^{(18.4KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812023392/kp2416Isup2.hkl

e-68-0m824-Isup2.hkl^{(164.3KB, hkl)}

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

Table 1. Selected bond lengths (Å).

Cr—O1	1.9618 (19)
Cr—O2	1.9907 (19)
Cr—O5	1.9547 (19)
Cr—O6	1.9642 (18)
Cr—O1W	1.9978 (18)
Cr—O2W	1.9891 (19)

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Table 2. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1W—H11W⋯O4ⁱ	0.85 (2)	1.84 (3)	2.686 (3)	172 (3)
O1W—H12W⋯O3ⁱⁱ	0.85 (2)	1.94 (3)	2.769 (3)	163 (3)
O2W—H21W⋯O3ⁱⁱⁱ	0.90 (2)	1.91 (2)	2.775 (3)	161 (3)
O2W—H21W⋯O4ⁱⁱⁱ	0.90 (2)	2.37 (3)	2.909 (3)	118 (2)
O2W—H22W⋯O4W^iv	0.89 (2)	1.89 (3)	2.770 (3)	176 (3)
O3W—H31W⋯O2^v	0.88 (2)	2.12 (4)	2.979 (3)	167 (4)
O3W—H32W⋯O1	0.88 (2)	2.03 (4)	2.861 (3)	157 (4)
O4W—H4W⋯O6	0.90 (2)	2.12 (3)	3.011 (3)	173 (3)
N1—H1A⋯O8^vi	0.86	2.15	2.911 (4)	147
N1—H1B⋯O3W^iv	0.86	2.07	2.900 (4)	161
N2—H2⋯O8^vi	0.86	2.13	2.900 (4)	150
N2—H2⋯O7^vi	0.86	2.25	2.897 (4)	132

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

supplementary crystallographic information

Comment

It is well known that the use of hydrogen-bonding and π-π stacking interactions is a successful way to obtain a large variety of hybrid (organic/inorganic) compounds with extended supramolecular networks through self-assembly (Zhang et al., 2000; Paraschiv et al., 2007). Following this strategy, we recently published the structure of an organic-inorganic hybrid salt: 4-aminopyridinium trans-diaquadioxalatochromate(III) monohydrate (Chérif et al., 2011). In this contribution, we report the crystal structure of an homologous salt with 2-amino-5-chloropyridinium as the organic cation.

The title compound appears to be the first member of salts of general formula (organic cation)[Cr(C₂O₄)₂(H₂O)₂].xH₂O where x = 0 or x = 1 in which the complex anion [Cr(C₂O₄)₂(H₂O)₂]^- adopts the cis geometry. The asymmetric unit is formed by a [Cr(C₂O₄)₂(H₂O)₂]^- anion, a (C₅H₆ClN₂)⁺ cation and 1.5 water molecules [The O4W atom is located on a special position (1/2, 0, z)] (Fig. 1). In the complex anion, each chromium atom is six-coordinated in a distorted octahedral geometry with two O water molecules in cis position and four oxalato-O atoms from two chelating oxalate groups (Table 1). The four Cr—O(ox) distances range from 1.955 (2) to 1.991 (2) Å; three of them in the range 1.955 (2)–1.965 (2) Å are comparable to those reported in similar compounds (Bélombé et al., 2009; Nenwa et al., 2010; Chérif et al., 2011) but the last one, Cr—O2, is slightly longer. The Cr—O(water) distances are shorter than those observed for the quinolinium and 4-dimethylaminopyridinium compounds (Bélombé et al., 2009; Nenwa et al., 2010).

The structure can be described as segregated positive (C₅H₆ClN₂)⁺ and negative [[Cr(C₂O₄)₂(H₂O)₂]^- + H₂O] layers parallel to (010) (Fig. 2) and interconnected via N—H···O and O—H···O hydrogen bonds (Blessing, 1986; Brown, 1976). In fact, an extensive network of hydrogen bonds contributes to the stabilization of the structure. O—H···O hydrogen bonds involving all water molecules and some of the oxalato-O atoms provide the cohesion of the positive layers. The two N atoms of (C₅H₆ClN₂)⁺ are hydrogen bonded to the peripheral O atoms of the oxalate groups (O8 and O7) and to the solvent water molecules (O3W) connecting the positive and negative layers (Fig. 3, Table 2).

Experimental

Ethanol solutions of C₅H₅ClN₂ (1 mmol) (10 mL) and H₂C₂O₄.2H₂O (2 mmol) (10 mL) were added to CrCl₃.6H₂O (1 mmol) dissolved in 10 mL of ethanol and stirred for 5 h. The resulting violet solution was left at room temperature and crystals suitable for X-ray diffraction were obtained after two weeks of slow evaporation.