2-Amino­pyridinium bis­(pyridine-2,6-dicarboxyl­ato)ferrate(III)

Masoud Mirzaei; Hossein Eshtiagh-Hosseini; Joel T Mague

doi:10.1107/S1600536812001493

. 2012 Jan 21;68(Pt 2):m174. doi: 10.1107/S1600536812001493

2-Aminopyridinium bis(pyridine-2,6-dicarboxylato)ferrate(III)

Masoud Mirzaei ^a,^*, Hossein Eshtiagh-Hosseini ^a, Joel T Mague ^b,^*

PMCID: PMC3274902 PMID: 22346849

Abstract

In the title compound, (C₅H₇N₂)[Fe(C₇H₃NO₄)₂] or [2-apyH][Fe(pydc)₂], the asymmetric unit contains an [Fe(pydc)₂]⁻ (pydc is pyridine-2,6-dicarboxylate) anion and a protonated 2-aminopyridine cation ([2-apyH]⁺). The complex anion contains an Fe^III atom within a distorted octahedral FeN₂O₄ coordination geometry. N—H⋯O and C—H⋯O hydrogen bonding, offset π–π stacking [centroid–centroid distance = 3.805 (13) Å] and C=O⋯π interactions [3.494 (14) Å] generate a three-dimensional network structure.

Related literature

For related structures, see: Mirzaei et al. (2011 ▶); Eshtiagh-Hosseini et al. (2010 ▶, 2011 ▶); Hseu et al. (1991 ▶); Marsh (1993 ▶); Aghabozorg, Nemati et al. (2007 ▶); Aghabozorg, Sadrkhanlou et al. (2007 ▶); Soleimannejad et al. (2010 ▶). For details on the importance of coordinative covalent bonds and weak intermolecular forces in forming extended organized networks, see: Steiner (2002 ▶). For graph-set analysis of hydrogen-bonding patterns, see: Bernstein et al. (1995 ▶).

Experimental

Crystal data

(C₅H₇N₂)[Fe(C₇H₃NO₄)₂]
M _r = 481.18
Orthorhombic,
a = 7.9288 (10) Å
b = 15.881 (2) Å
c = 30.069 (4) Å
V = 3786.2 (8) Å³
Z = 8
Mo Kα radiation
μ = 0.86 mm⁻¹
T = 100 K
0.34 × 0.25 × 0.08 mm

Data collection

Bruker SMART APEX CCD diffractometer
Absorption correction: numerical (SADABS; Sheldrick, 2009 ▶) T _min = 0.696, T _max = 0.932
62788 measured reflections
5007 independent reflections
4354 reflections with I > 2σ(I)
R _int = 0.051

Refinement

R[F ² > 2σ(F ²)] = 0.033
wR(F ²) = 0.086
S = 1.05
5007 reflections
301 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.47 e Å⁻³
Δρ_min = −0.38 e Å⁻³

Data collection: APEX2 (Bruker, 2010 ▶); cell refinement: SAINT (Bruker, 2009 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812001493/rz2696sup1.cif

e-68-0m174-sup1.cif^{(29.2KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812001493/rz2696Isup2.hkl

e-68-0m174-Isup2.hkl^{(245.3KB, hkl)}

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
N3—H3A⋯O2ⁱ	0.85 (2)	1.99 (2)	2.7786 (18)	153 (2)
N4—H4A⋯O2ⁱ	0.91 (3)	2.07 (3)	2.862 (2)	145 (2)
N4—H4B⋯O6ⁱⁱ	0.83 (2)	1.98 (2)	2.8045 (19)	171 (2)
C3—H3⋯O4ⁱⁱ	0.95	2.44	3.3466 (19)	159
C12—H12⋯O5ⁱⁱⁱ	0.95	2.43	3.281 (2)	150
C10—H10⋯O1^iv	0.95	2.58	3.2398 (19)	127

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

Acknowledgments

The authors express their appreciation to the Ferdowsi University of Mashhad for financial support of this research paper (grant No. P/18).

supplementary crystallographic information

Comment

For the synthesis of supramolecular systems, coordinative covalent bonds and weak intermolecular forces are important to the assembly into extended organized networks (Steiner, 2002). Our research group has worked on the synthesis of supramolecular systems including proton transfer compounds and their complexes and are exploring the role of non-covalent interactions such as hydrogen bonding, ion pairing and π-π stacking in constructing the supramolecular crystalline compounds and their metal complexes (Mirzaei et al., 2011; Eshtiagh-Hosseini et al., 2011, Eshtiagh-Hosseini, et al., 2010).

The asymmetric unit of the title compound (I) is shown in Fig. 1. The Fe atom is hexa-coordinated by two N and four O atoms from two (pydc)^2– ions resulting in a distorted octahedral coordination environment. Although it would be reasonable to consider O1, O3, O5, and O7 as the equatorial "plane" and the N1 and N2 atoms to occupy the apical positions, the geometric constraints of the pydc^2- ligand generate a considerable tetrahedral distortion of this "plane" as seen from the angles O1–Fe1–O3 and O5–Fe1–O7 which are, respectively 150.46 (5)° and 151.47 (5)°. Although the O1–Fe1–O3 and O5–Fe1–O7 planes are close to being orthogonal (dihedral angle = 88.49 (7)°), the remainder of the ligands are noticeably less so. In particular, the ligand containing N1 is folded along the O1···O3 line by 30.4 (1)° which is likely caused by a close contact with the carbonyl group containing O8 in the anion at 1 + x, y, z. This distortion is the largest of all those found in the related complexes [Cat][Fe(py-2,6-dc)₂] (Cat = (H₅O₂) (Hseu et al., 1991, Marsh et al., 1993), 2,9-dimethyl-1,10-phenanthrolinium (Aghabozorg, Sadrkhanlou et al., 2007), piperazinium (Aghabozorg, Nemati et al., 2007), 4,4'-bipyridinium (Soleimannejad et al., 2010), 2-aminopyrimidinium (Eshtiagh-Hosseini et al., 2011)).

The solid state architecture of I is generated via intermolecular N–H···O and C–H···O hydrogen bonding (Table 1 and Fig. 2) having the graph-set motifs R₄⁴(24) and R₂¹(6) as well as offset π-π stacking interactions between the pyridine unit containing N2 and the cation at 1 - x, -y, 1 - z (centroid-centroid distance = 3.805 (13) Å) and a C14═O8···π interaction with the centroid of the pyridine ring containing N1 (3.494 (14) Å).

Experimental

A solution of 2-aminopyridine (0.06 g, 0.60 mmol) and pyridine-2,6-dicarboxylic acid (0.05 g, 0.30 mmol) was refluxed for 1 h. Then a solution of FeCl₃.6H₂O (0.04 g, 0.15 mmol) was added dropwise and the refluxing continued for 6 hrs at 60°C. The resulting solution was light green in colour. After slow evaporation of solvent at laboratory temperature plate-like yellow crystals were collected.