Bis(4-amino­pyridinium) dichromate(VI)

Sonia Trabelsi; Thierry Roisnel; Hassouna Dhaouadi; Houda Marouani

doi:10.1107/S1600536814013579

. 2014 Jun 14;70(Pt 7):m263–m264. doi: 10.1107/S1600536814013579

Bis(4-aminopyridinium) dichromate(VI)

Sonia Trabelsi ^a, Thierry Roisnel ^b, Hassouna Dhaouadi ^c,^*, Houda Marouani ^a

PMCID: PMC4120631 PMID: 25161526

Abstract

The asymmetric unit of the title salt, (C₅H₇N₂)₂[Cr₂O₇], contains four independent cations and two independent dichromate anions. The crystal structure consists of discrete dichromate anions with an eclipsed conformation stacked in layers parallel to (010) at y = 1/4 and y = 3/4. These layers are linked via 4-aminopyridinium cations by N—H⋯O and weak C—H⋯O hydrogen bonds, forming a three-dimensional supramolecular network. In addition, π–π interactions are present in this structure; the shortest distance separating mean planes through 4-aminopyridinium cations is 3.679 (6) Å.

Related literature

For properties of pyridine-based compounds, see: Patani & LaVoie (1996 ▶); Ma & Huang (2003 ▶). For related structures, see: Trabelsi et al. (2012 ▶); Lennartson & Håkansson (2009 ▶); Fun et al. (2009 ▶); Ramesh et al. (2010 ▶). For aromatic π–π stacking interactions, see: Janiak (2000 ▶). graphic file with name e-70-0m263-scheme1.jpg

Experimental

Crystal data

(C₅H₇N₂)₂[Cr₂O₇]
M _r = 406.25
Monoclinic,
a = 13.8505 (4) Å
b = 16.2486 (4) Å
c = 15.2586 (4) Å
β = 118.923 (2)°
V = 3005.65 (14) Å³
Z = 8
Mo Kα radiation
μ = 1.49 mm⁻¹
T = 150 K
0.58 × 0.5 × 0.4 mm

Data collection

Bruker APEXII diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2006 ▶) T _min = 0.469, T _max = 0.552
23461 measured reflections
6868 independent reflections
5506 reflections with I > 2σ(I)
R _int = 0.042

Refinement

R[F ² > 2σ(F ²)] = 0.035
wR(F ²) = 0.097
S = 1.07
6868 reflections
415 parameters
H-atom parameters constrained
Δρ_max = 0.41 e Å⁻³
Δρ_min = −0.58 e Å⁻³

Data collection: APEX2 (Bruker, 2006 ▶); cell refinement: SAINT (Bruker, 2006 ▶); data reduction: SAINT; program(s) used to solve structure: SIR97 (Altomare et al., 1999 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: DIAMOND (Brandenburg & Putz, 2005 ▶); software used to prepare material for publication: WinGX (Farrugia, 2012 ▶) and CRYSCAL (T. Roisnel, local program).

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536814013579/bh2500sup1.cif

e-70-0m263-sup1.cif^{(23.1KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536814013579/bh2500Isup2.hkl

e-70-0m263-Isup2.hkl^{(329.3KB, hkl)}

Click here for additional data file.^{(5.8KB, cml)}

Supporting information file. DOI: 10.1107/S1600536814013579/bh2500Isup3.cml

CCDC reference: 1007743

Additional supporting information: 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—HN1⋯O10ⁱ	0.86	2.13	2.842 (3)	140
N2—H2A⋯O9ⁱⁱ	0.86	2.19	3.022 (3)	162
N2—H2B⋯O11ⁱⁱⁱ	0.86	2.13	2.978 (3)	167
N3—HN3⋯O5^iv	0.86	2.14	2.871 (3)	142
N4—H4A⋯O13ⁱⁱⁱ	0.86	2.32	3.067 (3)	145
N4—H4B⋯O14ⁱⁱ	0.86	2.14	2.965 (3)	160
N5—HN5⋯O5ⁱⁱ	0.86	2.11	2.890 (3)	151
N6—H6A⋯O2^iv	0.86	2.45	2.998 (3)	122
N6—H6B⋯O14^iv	0.86	2.10	2.923 (3)	160
N7—HN7⋯O4^v	0.86	2.22	2.927 (2)	139
N8—H8A⋯O8^iv	0.86	2.31	3.121 (3)	156
N8—H8B⋯O11	0.86	2.17	3.033 (3)	176
C1—H1⋯O7^vi	0.93	2.43	3.305 (3)	156
C5—H5⋯O6^iv	0.93	2.28	3.192 (3)	165
C6—H6⋯O1^vi	0.93	2.31	3.204 (3)	161
C9—H9⋯O12ⁱⁱ	0.93	2.47	3.359 (3)	161
C10—H10⋯O2^iv	0.93	2.40	3.209 (3)	145
C11—H11⋯O1ⁱⁱ	0.93	2.41	3.205 (3)	144
C14—H14⋯O12	0.93	2.46	3.248 (3)	143
C15—H15⋯O2^v	0.93	2.32	3.244 (3)	171
C16—H16⋯O7ⁱⁱ	0.93	2.37	3.197 (3)	148

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

supplementary crystallographic information

S1. Comment

Usually, pyridine can serve as an efficient bioisostere of benzene in drug design, and considerable interest has been shown in pyridine derivatives in the field of modern agrochemistry and medicinal chemistry, because substitution of the benzene by pyridine may result in good biological activity and low toxicity of molecules containing the pyridyl moiety (Patani & LaVoie, 1996; Ma & Huang, 2003). In this work, we report the preparation and the structural investigation of a new organic dichromate, (C₅H₇N₂)₂·Cr₂O₇, (I).

The asymmetric unit of (I) is composed of two independent dichromate anions and four independent 4-aminopyridinium cations (Fig. 1). The structure of the compound consists of discrete dichromate ions with an eclipsed conformation stacked in layers parallel to the (010) plane at y = 0.25 and 0.75. These layers are linked via the 4-aminopidridinium cations by N—H···O and C—H···O hydrogen bonds, forming a three-dimensional supramolecular network as shown in figure 2.

Interatomic bond lengths and angles of the dichromate anions spread respectively within the ranges [1.6038 (17)–1.8059 (17) Å] and [105.42 (8)–112.22 (10)°] for O—Cr—O angles and [120.12 (9)–125.63 (9)°] for Cr—O—Cr angles. These geometrical features have also been noticed in other related crystal structure (Trabelsi et al., 2012; Lennartson & Håkansson, 2009).

In this atomic arrangement four independent 4-aminopyridinium cations are present. Examination of the organic cations shows that the bond distances and angles show no significant difference from those obtained in oxalate and picrate salts involving the same organic group (Fun et al., 2009; Ramesh et al., 2010). Each 4-aminopyridinium cations is planar, with a maximum deviation of 0.0024 (2) Å. The shortest inter-planar distance between nearby pyridine rings is 3.679 (6) Å, which is much shorter than 3.80 Å, indicating the formation of π–π interactions (Fig. 3, Janiak, 2000).

The established H-bonds of types N—H···O and C—H···O involve O atoms of the dichromate anions as acceptors, and the protonated N atoms and carbon atoms of 4-aminopyridinium as donors.

S2. Experimental

Single crystals of the title compound were prepared at room temperature by dissolving CrO₃ (0.10 g, 1 mmol) and 4-aminopyridine (Fampridine, 0.09 g, 1 mmol) in distilled water (20 ml). The resulting solution was stirred during 1 h, filtered and then evaporated slowly at room temperature until the formation of orange prismatic single crystals.