organic compounds
1,1′-(Ethane-1,2-diyl)bis(1,4,7-triazonane)
aMain Building, School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT, Wales
*Correspondence e-mail: knightjc@cardiff.ac.uk
In the centrosymmetric title compound (dtne), C14H32N6, two 1,4,7-triazacyclononane (tacn, or 1,4,7-triazonane) moieties are linked together each at an amino position by a single ethylene spacer. The molecular packing is supported by pairs of intermolecular N—H⋯N hydrogen bonds, which form R22(22) ring motifs and link the molecules into infinite chains running parallel to the a axis.
Related literature
For an investigation into the coordination chemistry of dtne derivatives and similarly bridged polyaza macrocyclic frameworks, see: Schröder et al. (2000). For dinuclear metal complexes of related ligands, see: Sinnecker et al. (2004); Marlin et al. (2005). For the of the related compound 1,4,7-triazacyclononane (tacn), see: Battle et al. (2005). For the structures of other metal complexes of dtne, see: Li et al. (2009). For hydrogen-bond motifs, see: Bernstein et al. (1995). For the preparation of a similar compound, see: Burdinski et al. (2000).
Experimental
Crystal data
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Refinement
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Data collection: COLLECT (Nonius, 2000); cell SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO (Otwinowski & Minor, 1997) and SCALEPACK; program(s) used to solve structure: SIR92 (Altomare et al., 1993); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001); software used to prepare material for publication: WinGX (Farrugia, 1999).
Supporting information
https://doi.org/10.1107/S1600536810019562/sj5006sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810019562/sj5006Isup2.hkl
1,2-Bis(1,4,7-triaza-1-cyclononyl)ethane, commonly referred to by the abbreviation dtne, was prepared by a modification of the procedure for that of 1,2-bis(4-methyl-1,4,7-triazacyclononyl)ethane (Me4dtne) reported by Burdinski et al., 2000. To a stirred solution of 1,4,7-triazatricyclo[5.2.1.04,10]decane (6.96 g, 5 mmol) in dry acetonitrile (25 ml) was added 1,2-dibromoethane (4.51 g, 2.4 mmol). After 5 days an off-white hygroscopic precipitate was collected by filtration and subsequently dissolved in 6 M hydrochloric acid (100 ml). The resulting solution was heated at reflux for 3 days after which the solvent was removed by evaporation under reduced pressure. The title compound was isolated by the addition of 10 M NaOH (20 ml) and subsequent removal of water by azeotropic distillation with toluene and a water collector. Solvent removal under reduced pressure afforded the title compound as a low melting slightly yellow solid. Crystals appropriate for data collection were obtained by slow diffusion of diethyl ether into a chloroform solution under an inert atmosphere.
The carbon bound H atoms were placed in calculated positions and subsequently treated as riding with C—H distances of 0.99 Å and Uiso(H) = 1.2Ueq(C). The hydrogen atoms located on N1 and N2 were located on a difference map and freely refined with individual isotropic temperature factors. The deepest hole in electron density (-0.33 e A-3) is located at a distance of 0.94 Å from C5.
The coordination chemistry of ligand frameworks which contain two tacn moieties linked by two to six carbon atoms has been extensively studied (Schröder et al., 2000). The ability of these so-called "earmuff" ligands to form dinuclear metal complexes, in which two metal centres lie in close proximity, has provided a useful means of investigating the active sites of various biological systems. For example, the dinuclear manganese complexes of ligands dtne (Sinnecker et al., 2004) and 1,2-bis(4,7-dimethyl-1,4,7-triaza-1-cyclononyl)ethane (Me4dtne) (Marlin et al., 2005) have received particular attention as a means of investigating Photosystem II. Whilst crystal structures of several dtne transition metal complexes have been reported (Li et al., 2009), the structure of the free ligand in the solid state has, until now, remained elusive.
We can report that dtne crystallizes in the triclinic
P -1 with one molecule in the The contains one-half molecule with the other half generated by a centre of inversion which lies at the midpoint of the C7—C7i bond [Symmetry code: (i) = -x, -y, -z] (Figure 1). The bond lengths and angles within each tacn moiety are comparable to those found in the of 1,4,7-triazacyclononane hemihydrate (Battle et al., 2005). The N3—C7—C7i bond angle is 112.12 (15) ° which indicates no significant stretching or compression of the ethylene bridge. The molecular packing (Figure 2) is supported by pairs of N—H···N hydrogen bonds between N1 and N2ii [Symmetry code: (ii) = x-1, y, z] (Figure 3). These H-bond interactions generate R22(22) ring motifs (Bernstein et al., 1995) and link the molecules into supramolecular one-dimensional chains which run parallel to the a-axis.For an investigation into the coordination chemistry of dtne derivatives and similarly bridged polyaza macrocyclic frameworks, see: Schröder et al. (2000). For dinuclear metal complexes of related ligands, see: Sinnecker et al. (2004); Marlin et al. (2005). For the
of the related compound 1,4,7-triazacyclononane (tacn), see: Battle et al. (2005). For the structures of other metal complexes of dtne, see: Li et al. (2009). For hydrogen-bond motifs, see: Bernstein et al. (1995). For the preparation of a similar compound, see: Burdinski et al. (2000).Data collection: COLLECT (Nonius, 2000); cell
SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO and SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SIR92 (Altomare et al., 1993); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001); software used to prepare material for publication: WinGX (Farrugia, 1999).C14H32N6 | Z = 1 |
Mr = 284.46 | F(000) = 158 |
Triclinic, P1 | Dx = 1.18 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 6.2732 (3) Å | Cell parameters from 6758 reflections |
b = 6.4988 (3) Å | θ = 1.0–27.5° |
c = 10.7152 (6) Å | µ = 0.08 mm−1 |
α = 99.751 (2)° | T = 150 K |
β = 93.115 (2)° | Block, colourless |
γ = 110.410 (3)° | 0.4 × 0.28 × 0.28 mm |
V = 400.45 (3) Å3 |
Bruker–Nonius KappaCCD diffractometer | 1806 independent reflections |
Radiation source: fine-focus sealed tube | 1599 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.099 |
φ and ω scans | θmax = 27.5°, θmin = 1.9° |
Absorption correction: multi-scan (SORTAV; Blessing, 1995) | h = −7→8 |
Tmin = 0.649, Tmax = 0.985 | k = −8→8 |
4952 measured reflections | l = −13→13 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.068 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.208 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.23 | w = 1/[σ2(Fo2) + (0.0859P)2 + 0.2591P] where P = (Fo2 + 2Fc2)/3 |
1806 reflections | (Δ/σ)max < 0.001 |
99 parameters | Δρmax = 0.30 e Å−3 |
0 restraints | Δρmin = −0.33 e Å−3 |
C14H32N6 | γ = 110.410 (3)° |
Mr = 284.46 | V = 400.45 (3) Å3 |
Triclinic, P1 | Z = 1 |
a = 6.2732 (3) Å | Mo Kα radiation |
b = 6.4988 (3) Å | µ = 0.08 mm−1 |
c = 10.7152 (6) Å | T = 150 K |
α = 99.751 (2)° | 0.4 × 0.28 × 0.28 mm |
β = 93.115 (2)° |
Bruker–Nonius KappaCCD diffractometer | 1806 independent reflections |
Absorption correction: multi-scan (SORTAV; Blessing, 1995) | 1599 reflections with I > 2σ(I) |
Tmin = 0.649, Tmax = 0.985 | Rint = 0.099 |
4952 measured reflections |
R[F2 > 2σ(F2)] = 0.068 | 0 restraints |
wR(F2) = 0.208 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.23 | Δρmax = 0.30 e Å−3 |
1806 reflections | Δρmin = −0.33 e Å−3 |
99 parameters |
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. |
x | y | z | Uiso*/Ueq | ||
N1 | 0.1344 (3) | 0.5390 (3) | 0.32247 (17) | 0.0229 (4) | |
H1 | 0.145 (5) | 0.533 (5) | 0.233 (3) | 0.033 (7)* | |
N2 | 0.6399 (3) | 0.5507 (3) | 0.29452 (16) | 0.0202 (4) | |
H2 | 0.775 (5) | 0.583 (4) | 0.312 (2) | 0.019 (6)* | |
N3 | 0.1962 (3) | 0.1707 (3) | 0.15019 (15) | 0.0200 (4) | |
C1 | 0.3489 (3) | 0.6779 (3) | 0.4061 (2) | 0.0231 (5) | |
H1A | 0.3671 | 0.5978 | 0.4744 | 0.028* | |
H1B | 0.3328 | 0.819 | 0.4475 | 0.028* | |
C2 | 0.5687 (3) | 0.7378 (3) | 0.3420 (2) | 0.0234 (5) | |
H2A | 0.5468 | 0.808 | 0.2696 | 0.028* | |
H2B | 0.6945 | 0.8513 | 0.404 | 0.028* | |
C3 | 0.5883 (3) | 0.4564 (3) | 0.15762 (18) | 0.0234 (5) | |
H3A | 0.7345 | 0.473 | 0.1221 | 0.028* | |
H3B | 0.5167 | 0.5461 | 0.1168 | 0.028* | |
C4 | 0.4308 (3) | 0.2106 (3) | 0.12080 (18) | 0.0225 (5) | |
H4A | 0.4267 | 0.1575 | 0.0282 | 0.027* | |
H4B | 0.4954 | 0.1211 | 0.1664 | 0.027* | |
C5 | 0.1748 (3) | 0.1640 (3) | 0.28616 (18) | 0.0211 (5) | |
H5A | 0.329 | 0.2224 | 0.3355 | 0.025* | |
H5B | 0.0966 | 0.0072 | 0.2955 | 0.025* | |
C6 | 0.0377 (3) | 0.3056 (3) | 0.33779 (19) | 0.0230 (5) | |
H6A | −0.1207 | 0.2366 | 0.2934 | 0.028* | |
H6B | 0.0293 | 0.3037 | 0.4296 | 0.028* | |
C7 | 0.0265 (4) | −0.0249 (3) | 0.06487 (18) | 0.0241 (5) | |
H7A | −0.1166 | −0.0741 | 0.1049 | 0.029* | |
H7B | 0.0849 | −0.1493 | 0.0528 | 0.029* |
U11 | U22 | U33 | U12 | U13 | U23 | |
N1 | 0.0170 (8) | 0.0243 (9) | 0.0240 (9) | 0.0054 (7) | 0.0015 (6) | 0.0006 (7) |
N2 | 0.0140 (8) | 0.0237 (9) | 0.0189 (8) | 0.0049 (6) | 0.0007 (6) | −0.0013 (6) |
N3 | 0.0168 (8) | 0.0211 (8) | 0.0152 (8) | 0.0016 (6) | 0.0000 (6) | −0.0021 (6) |
C1 | 0.0182 (9) | 0.0242 (10) | 0.0229 (10) | 0.0068 (8) | 0.0025 (7) | −0.0037 (8) |
C2 | 0.0190 (9) | 0.0193 (9) | 0.0276 (10) | 0.0033 (7) | 0.0038 (7) | 0.0009 (8) |
C3 | 0.0199 (9) | 0.0266 (10) | 0.0183 (9) | 0.0033 (8) | 0.0038 (7) | 0.0010 (8) |
C4 | 0.0205 (10) | 0.0246 (10) | 0.0181 (9) | 0.0061 (8) | 0.0024 (7) | −0.0028 (7) |
C5 | 0.0209 (9) | 0.0214 (9) | 0.0166 (9) | 0.0034 (7) | 0.0007 (7) | 0.0018 (7) |
C6 | 0.0174 (9) | 0.0243 (10) | 0.0226 (10) | 0.0028 (7) | 0.0043 (7) | 0.0016 (8) |
C7 | 0.0231 (10) | 0.0193 (9) | 0.0205 (10) | −0.0007 (7) | −0.0025 (7) | −0.0014 (8) |
N1—C6 | 1.466 (3) | C3—C4 | 1.526 (3) |
N1—C1 | 1.475 (2) | C3—H3A | 0.99 |
N1—H1 | 0.96 (3) | C3—H3B | 0.99 |
N2—C2 | 1.460 (3) | C4—H4A | 0.99 |
N2—C3 | 1.462 (2) | C4—H4B | 0.99 |
N2—H2 | 0.80 (3) | C5—C6 | 1.524 (3) |
N3—C7 | 1.464 (2) | C5—H5A | 0.99 |
N3—C4 | 1.464 (2) | C5—H5B | 0.99 |
N3—C5 | 1.477 (2) | C6—H6A | 0.99 |
C1—C2 | 1.531 (3) | C6—H6B | 0.99 |
C1—H1A | 0.99 | C7—C7i | 1.525 (4) |
C1—H1B | 0.99 | C7—H7A | 0.99 |
C2—H2A | 0.99 | C7—H7B | 0.99 |
C2—H2B | 0.99 | ||
C6—N1—C1 | 114.96 (17) | H3A—C3—H3B | 107.5 |
C6—N1—H1 | 106.1 (17) | N3—C4—C3 | 113.41 (16) |
C1—N1—H1 | 114.6 (17) | N3—C4—H4A | 108.9 |
C2—N2—C3 | 117.19 (17) | C3—C4—H4A | 108.9 |
C2—N2—H2 | 111.5 (17) | N3—C4—H4B | 108.9 |
C3—N2—H2 | 106.5 (18) | C3—C4—H4B | 108.9 |
C7—N3—C4 | 112.85 (15) | H4A—C4—H4B | 107.7 |
C7—N3—C5 | 112.41 (15) | N3—C5—C6 | 109.75 (16) |
C4—N3—C5 | 112.25 (15) | N3—C5—H5A | 109.7 |
N1—C1—C2 | 116.37 (17) | C6—C5—H5A | 109.7 |
N1—C1—H1A | 108.2 | N3—C5—H5B | 109.7 |
C2—C1—H1A | 108.2 | C6—C5—H5B | 109.7 |
N1—C1—H1B | 108.2 | H5A—C5—H5B | 108.2 |
C2—C1—H1B | 108.2 | N1—C6—C5 | 113.78 (16) |
H1A—C1—H1B | 107.3 | N1—C6—H6A | 108.8 |
N2—C2—C1 | 115.49 (16) | C5—C6—H6A | 108.8 |
N2—C2—H2A | 108.4 | N1—C6—H6B | 108.8 |
C1—C2—H2A | 108.4 | C5—C6—H6B | 108.8 |
N2—C2—H2B | 108.4 | H6A—C6—H6B | 107.7 |
C1—C2—H2B | 108.4 | N3—C7—C7i | 112.1 (2) |
H2A—C2—H2B | 107.5 | N3—C7—H7A | 109.2 |
N2—C3—C4 | 115.55 (17) | C7i—C7—H7A | 109.2 |
N2—C3—H3A | 108.4 | N3—C7—H7B | 109.2 |
C4—C3—H3A | 108.4 | C7i—C7—H7B | 109.2 |
N2—C3—H3B | 108.4 | H7A—C7—H7B | 107.9 |
C4—C3—H3B | 108.4 | ||
C6—N1—C1—C2 | 106.9 (2) | C7—N3—C5—C6 | −97.75 (19) |
C3—N2—C2—C1 | 101.1 (2) | C4—N3—C5—C6 | 133.75 (17) |
N1—C1—C2—N2 | −67.9 (2) | C1—N1—C6—C5 | −71.3 (2) |
C2—N2—C3—C4 | −118.6 (2) | N3—C5—C6—N1 | −56.6 (2) |
C7—N3—C4—C3 | 151.78 (17) | C4—N3—C7—C7i | −77.7 (3) |
C5—N3—C4—C3 | −79.9 (2) | C5—N3—C7—C7i | 154.1 (2) |
N2—C3—C4—N3 | 67.4 (2) |
Symmetry code: (i) −x, −y, −z. |
D—H···A | D—H | H···A | D···A | D—H···A |
N2—H2···N1ii | 0.80 (3) | 2.37 (3) | 3.129 (3) | 159 (2) |
Symmetry code: (ii) x+1, y, z. |
Experimental details
Crystal data | |
Chemical formula | C14H32N6 |
Mr | 284.46 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 150 |
a, b, c (Å) | 6.2732 (3), 6.4988 (3), 10.7152 (6) |
α, β, γ (°) | 99.751 (2), 93.115 (2), 110.410 (3) |
V (Å3) | 400.45 (3) |
Z | 1 |
Radiation type | Mo Kα |
µ (mm−1) | 0.08 |
Crystal size (mm) | 0.4 × 0.28 × 0.28 |
Data collection | |
Diffractometer | Bruker–Nonius KappaCCD |
Absorption correction | Multi-scan (SORTAV; Blessing, 1995) |
Tmin, Tmax | 0.649, 0.985 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 4952, 1806, 1599 |
Rint | 0.099 |
(sin θ/λ)max (Å−1) | 0.650 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.068, 0.208, 1.23 |
No. of reflections | 1806 |
No. of parameters | 99 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.30, −0.33 |
Computer programs: COLLECT (Nonius, 2000), DENZO and SCALEPACK (Otwinowski & Minor, 1997), SIR92 (Altomare et al., 1993), SHELXL97 (Sheldrick, 2008), X-SEED (Barbour, 2001), WinGX (Farrugia, 1999).
D—H···A | D—H | H···A | D···A | D—H···A |
N2—H2···N1i | 0.80 (3) | 2.37 (3) | 3.129 (3) | 159 (2) |
Symmetry code: (i) x+1, y, z. |
Acknowledgements
This project was supported by the EPSRC (research grant No. EP/E030122/1).
References
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The coordination chemistry of ligand frameworks which contain two tacn moieties linked by two to six carbon atoms has been extensively studied (Schröder et al., 2000). The ability of these so-called "earmuff" ligands to form dinuclear metal complexes, in which two metal centres lie in close proximity, has provided a useful means of investigating the active sites of various biological systems. For example, the dinuclear manganese complexes of ligands dtne (Sinnecker et al., 2004) and 1,2-bis(4,7-dimethyl-1,4,7-triaza-1-cyclononyl)ethane (Me4dtne) (Marlin et al., 2005) have received particular attention as a means of investigating Photosystem II. Whilst crystal structures of several dtne transition metal complexes have been reported (Li et al., 2009), the structure of the free ligand in the solid state has, until now, remained elusive.
We can report that dtne crystallizes in the triclinic space group P -1 with one molecule in the unit cell. The asymmetric unit contains one-half molecule with the other half generated by a centre of inversion which lies at the midpoint of the C7—C7i bond [Symmetry code: (i) = -x, -y, -z] (Figure 1). The bond lengths and angles within each tacn moiety are comparable to those found in the crystal structure of 1,4,7-triazacyclononane hemihydrate (Battle et al., 2005). The N3—C7—C7i bond angle is 112.12 (15) ° which indicates no significant stretching or compression of the ethylene bridge. The molecular packing (Figure 2) is supported by pairs of N—H···N hydrogen bonds between N1 and N2ii [Symmetry code: (ii) = x-1, y, z] (Figure 3). These H-bond interactions generate R22(22) ring motifs (Bernstein et al., 1995) and link the molecules into supramolecular one-dimensional chains which run parallel to the a-axis.