N,N-Bis(2-pyridylmeth­yl)-tert-butyl­amine

Allen Mambanda; Deogratius Jaganyi; Kirsty Stewart

doi:10.1107/S1600536809001366

. 2009 Jan 28;65(Pt 2):o402. doi: 10.1107/S1600536809001366

N,N-Bis(2-pyridylmethyl)-tert-butylamine

Allen Mambanda ^a, Deogratius Jaganyi ^a, Kirsty Stewart ^a,^*

PMCID: PMC2968317 PMID: 21581995

Abstract

In the title compound, C₁₆H₂₁N₃, the dihedral angle between the two pyridine rings is 88.11 (9)°. In the crystal, molecules are linked through intermolecular C—H⋯π interactions, forming a layer expanding parallel to the (10 Inline graphic ) plane.

Related literature

For related compounds, see: Mambanda et al. (2007 ▶); Foxon et al. (2007 ▶); Fujihara et al. (2004 ▶); Munro & Camp (2003 ▶). For metal complexes with the title compound as a ligand, see: Fujii et al. (2003 ▶); Lee & Lippard (2002 ▶); Mok et al. (1997 ▶). For the metal complex with N,N-bis(2-pyridylmethyl)ethylamine as a ligand, see: Pal et al. (1992 ▶).

Experimental

Crystal data

C₁₆H₂₁N₃
M _r = 255.36
Monoclinic,
a = 6.1808 (3) Å
b = 17.9502 (8) Å
c = 13.7079 (6) Å
β = 100.239 (4)°
V = 1496.62 (12) Å³
Z = 4
Mo Kα radiation
μ = 0.07 mm⁻¹
T = 293 (2) K
0.50 × 0.50 × 0.30 mm

Data collection

Oxford Diffraction Xcalibur2 CCD diffractometer
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2008 ▶) T _min = 0.967, T _max = 0.980
7475 measured reflections
2392 independent reflections
2024 reflections with I > 2σ(I)
R _int = 0.012

Refinement

R[F ² > 2σ(F ²)] = 0.043
wR(F ²) = 0.119
S = 1.02
2392 reflections
175 parameters
2 restraints
H-atom parameters constrained
Δρ_max = 0.21 e Å⁻³
Δρ_min = −0.22 e Å⁻³

Data collection: CrysAlis CCD (Oxford Diffraction, 2008 ▶); cell refinement: CrysAlis RED (Oxford Diffraction, 2008 ▶); data reduction: CrysAlis RED; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809001366/is2355sup1.cif

e-65-0o402-sup1.cif^{(18.2KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809001366/is2355Isup2.hkl

e-65-0o402-Isup2.hkl^{(115.2KB, hkl)}

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

Table 1. Hydrogen-bond geometry (Å, °).

Cg1 and Cg2 are the centroids of the N2/C3–C7and N3/C9–C13 rings, respectively.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C7—H1⋯Cg2ⁱ	0.93	2.97	3.819 (2)	153
C15—H16⋯Cg1ⁱⁱ	0.96	2.94	3.836 (2)	156

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

Acknowledgments

The authors gratefully acknowledge financial support from the University of Kwazulu-Natal and the South African National Research Foundation. We thank Mr C. Grimmer for the NMR analysis of the samples. We also thank Professor O. Q Munro and Professor J. Field for their guidance.

supplementary crystallographic information

Comment

The title compound is a versatile tridentate N-donor ligand, and it (Fujii et al., 2003; Lee & Lippard, 2002; Mok et al., 1997) and its analogue, N, N-bis(2-pyridylmethyl)ethylamine (Pal et al., 1992) have been used extensively in metal coordination. The related crystal structures of symmetrical bis(tridentate) ligands have been reportd (Mambanda et al., 2007; Foxon et al., 2007; Fujihara et al., 2004).

The crystal structure of the title compound (Fig. 1) shows that the three nitrogen atoms (one sp³ and two pyridine sp²) are not suitability orientated for pincer-like coordination to a metal. Rotation about the C2—C3 and C8—C9 bonds are required for that to occur. The relative orientation of the two pyridine rings is reflected in a dihedral angle between their mean planes of 88.11 (9)°, clearly this angle would have to change were the ligand to bind to a metal centre. The steric influence of the bulky tert-butyl group is reflected in the C1—N1—C2 and C1—N1—C8 angles [113.90 (13) and 115.34 (13)°, respectively], being larger than the C2—N1—C8 angle of 110.08 (13)°. The methylene groups of the structure all adopt the expected staggered (lowest energy) conformation (Munro & Camp, 2003). The pyridyl ring containing atom N2 is orientated at 18 (1)° relative to the mean plane of the N-tert-butyl group (plane through C16—C1—N1), whilst that containing N3 is orientated at 74 (1)°.

There are no short van der Waals contacts less than the sum of the van der Waals radii in this system, reflected in the loose packing, however weak (possibly stabilizing) C—H···π intermolecular interactions do occur. The metrics of such interactions reflect a T-shaped, edge-to-face geometry. Specifically, let us define Cg1 as the centre of gravity of the pyridyl N2/C3–C7 ring and Cg2 the centre of gravity of the pyridyl N3/C9–C13 ring. A C—H···π interaction with a separation of 2.97 (1) Å exists between C7—H1 from the pyridyl ring containing atom N2 and Cg2 of neighbouring symmetry related molecule [symmetry code: (i) x - 1/2, y - 1/2, z] (Table 1). A similar C—H···π interaction with a separation of 2.94 (1) Å exists between C15—H16 from one of the methyl groups of the tert-butyl moiety and Cg1 on the symmetry related neighbouring molecule with symmetry code: (ii) x, -y, z - 1/2. Figure 2 shows the packing within the unit cell for the title compound.

Experimental

The compound was synthesized following a literature method (Pal et al., 1992). Under a high flow of nitrogen, 6 ml of 20% NaOH solution was added to an aqueous solution of 2-picolyl chloridehydrochloride [(3.937 g (24 mmol) in 0.5 ml ultra pure water] to form a pink emulsion solution. 2-Amino-2-methyl propane (12 mmol) was added and the mixture stirred at 60°C. 40 ml of 20% NaOH solution was then added over a period of 1 h and the mixture left to stir for a further 12 h. The crude product was extracted with CHCl₃ washed with ultra pure water and dried over Na₂SO₄. Excess solvent was removed under reduced pressure and the oil residue purified on a short chromatographic column packed with 0.5 g charcoal and 5 g of neutral alumina using CHCl₃ as an eluent to afford a light yellow solution. Colourless single crystals suitable for X-ray diffraction were obtained from slow evaporation of the solvent from its solution made from a 5% chloroform in ethanol solution (yield: 1.73 g, 60%).

Spectroscopic data: ¹H NMR (400 MHz, CDCl₃) δ / p.p.m.: 8.40 (d, 2H), 7.60 (t, 2H), 7.45 (d, 2H), 7.05 (t, 2H), 3.95 (s, 4H), 1.18 (s, 9H). ¹³C NMR (125 MHz, CDCl₃) δ / p.p.m.: 27.0, 57.0, 122.0, 123.0,136.0, 148.0, 160. Anal. Calc. for C₁₆H₂₁N₃: C 75.26, H 8.29, N 16.46; Found: C 74.89, H 7.97, N 17.37.