2,7-Dimethyl-2,7-diazo­niapyrene bis­(hexa­fluoro­phosphate)

Li Ang

doi:10.1107/S1600536811001978

. 2011 Jan 29;67(Pt 2):o508. doi: 10.1107/S1600536811001978

2,7-Dimethyl-2,7-diazoniapyrene bis(hexafluorophosphate)

Li Ang ^a,^*

PMCID: PMC3051768 PMID: 21523159

Abstract

In the title compound, C₁₆H₁₄N₂ ²⁺·2PF₆ ⁻, the 2,7-dimethyl-2,7-diazapyrenium (DM-diaz) cation lies on a crystallographic twofold rotation axes. The diaz groups are nearly coplanar, with a maximum deviation of 0.008 (3) Å. In the crystal, molecules are linked into a two-dimensional lamellar framework parallel to (104) through weak C—H⋯F interactions.

Related literature

For general background to 2,7-disubstituted diazapyrenium dications, see: Ashton et al. (1999 ▶); Yen et al. (2009 ▶); Steuerman et al. (2004 ▶); Lilienthal et al. (1996 ▶); Sindelar et al. (2005 ▶); Lin et al. (2006 ▶). For related structures, see: Blake et al. (1997 ▶); Dinolfo et al. (2004 ▶).

Experimental

Crystal data

C₁₆H₁₄N₂ ²⁺·2PF₆ ⁻
M _r = 524.23
Monoclinic,
a = 6.7654 (14) Å
b = 10.653 (2) Å
c = 13.422 (3) Å
β = 91.03 (3)°
V = 967.2 (3) Å³
Z = 2
Mo Kα radiation
μ = 0.35 mm⁻¹
T = 293 K
0.31 × 0.31 × 0.19 mm

Data collection

Rigaku R-AXIS RAPID diffractometer
Absorption correction: multi-scan (ABSCOR; Higashi, 1995 ▶) T _min = 0.899, T _max = 0.937
7699 measured reflections
1756 independent reflections
1439 reflections with I > 2σ(I)
R _int = 0.021

Refinement

R[F ² > 2σ(F ²)] = 0.059
wR(F ²) = 0.182
S = 1.06
1756 reflections
146 parameters
H-atom parameters constrained
Δρ_max = 0.48 e Å⁻³
Δρ_min = −0.34 e Å⁻³

Data collection: RAPID-AUTO (Rigaku, 1998 ▶); cell refinement: RAPID-AUTO; data reduction: CrystalStructure (Rigaku/MSC, 2004 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEPII (Johnson, 1976 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536811001978/bg2385sup1.cif

e-67-0o508-sup1.cif^{(14.5KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811001978/bg2385Isup2.hkl

e-67-0o508-Isup2.hkl^{(86.5KB, 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
C6—H6⋯F2ⁱ	0.93	2.48	3.367 (4)	160
C7—H7⋯F4ⁱⁱ	0.93	2.51	3.418 (5)	167

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

Acknowledgments

This work was supported by the fund of Zhejiang Gongshang University (No. 10–3).

supplementary crystallographic information

Comment

2,7-Disubstituted diazapyrenium dications, which combine the features of pyrene, methylviologen, and nucletic acid intercalators, are charming pi-electron deficient building blocks in supramolecular chemistry (Ashton et al., 1999; Yen et al., 2009). They have been widely used as the electron-acceptors for electron-donating units such as hydroquinones and aromatic carboxylates (Steuerman et al., 2004; Lilienthal et al., 1996). Furthermore, due to their luminescence properties, they have also been as fluorescence probes for ion detection (Sindelar et al., 2005) and neurotransmition (Lin et al., 2006). Herein, we report the crystal structure of one of these disubstituted diazapyrenium dications, the N,N'-dimethyl-2,7-diazapyrenium, C₁₆H₁₄N₂.2PF₆, (DM-diaz).

The cation lies on a crystallographic twofold rotation axes; diaz groups are nearly coplanar with a maximum deviation of 0.008 (3) Å. Unlike many structures that contain diaz (Blake et al., 1997; Dinolfo et al., 2004), Dm-diaz exhibits no face-to-face pi-pi interactions between diaz molecules in the structure. C—H···F interactions are observed between the methyl groups of the DM-diaz molecules and hexafluorophoshate counterions (Table 1), forming a two-dimensional lamellar framework parallel to (101) (Figure 2).

Experimental

A solution of 2,7-diazapyrene (0.210 g, 1.03 mmol) and iodomethane (0.568 g, 4.02 mmol) in acetonitrile (15 ml) was stirred and refluxed for 3 h. After it was cooled to room temperature, a red solid was isolated on a filter and washed with ethyl ether (30 ml). The solid was dissolved with water (75 ml) and a saturated aqueous solution of NH₄PF₆ (2.44 g, 15.0 mmol) was added until no further precipitate was observed. The red solid was isolated on a filter, washed with water and dried under vacuum to afford the product (0.423 g, 78.4%). Red crystals were obtained by vapor diffusion of isopropyl ether into an acetonitrile solution over a period of 5 d. ¹H NMR (500 MHz, CD₃CN, 295 K) δ (p.p.m.) 9.88 (4H,s), 8.85 (4H, s), 5.14 (4H, t, J = 5.2 Hz), 3.45 (4H, m), 3.45 (2H, t, J = 5.5 Hz).