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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

(Received 14 May 2010; accepted 25 May 2010; online 29 May 2010)

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[Schröder, M., Blake, A. J., Danks, J. P., Li, W.-S. & Lippolis, V. (2000). J. Chem. Soc. Dalton Trans. pp. 3034-3040.]). For dinuclear metal complexes of related ligands, see: Sinnecker et al. (2004[Sinnecker, S., Neese, F., Noodleman, L. & Lubitz, W. (2004). J. Am. Chem. Soc. 126, 2613-2622.]); Marlin et al. (2005[Marlin, D. S., Bill, E., Weyhermüller, T., Bothe, E. & Wieghardt, K. (2005). J. Am. Chem. Soc. 127, 6095-6108.]). For the crystal structure of the related compound 1,4,7-triaza­cyclo­nonane (tacn), see: Battle et al. (2005[Battle, A. R., Johnson, D. L. & Martin, L. L. (2005). Acta Cryst. E61, o330-o332.]). For the structures of other metal complexes of dtne, see: Li et al. (2009[Li, Q.-X., Wang, X.-F., Cai, L., Li, Q., Meng, X.-G., Xuan, A.-G., Huang, S.-Y. & Ai, J. (2009). Inorg. Chem. Commun. 12, 145-147.]). For hydrogen-bond motifs, see: Bernstein et al. (1995[Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555-1573.]). For the preparation of a similar compound, see: Burdinski et al. (2000[Burdinski, D., Bothe, E. & Wieghardt, K. (2000). Inorg. Chem. 39, 105-116.]).

[Scheme 1]

Experimental

Crystal data
  • C14H32N6

  • Mr = 284.46

  • Triclinic, [P \overline 1]

  • a = 6.2732 (3) Å

  • b = 6.4988 (3) Å

  • c = 10.7152 (6) Å

  • α = 99.751 (2)°

  • β = 93.115 (2)°

  • γ = 110.410 (3)°

  • V = 400.45 (3) Å3

  • Z = 1

  • Mo Kα radiation

  • μ = 0.08 mm−1

  • T = 150 K

  • 0.4 × 0.28 × 0.28 mm

Data collection
  • Bruker–Nonius KappaCCD diffractometer

  • Absorption correction: multi-scan (SORTAV; Blessing, 1995[Blessing, R. H. (1995). Acta Cryst. A51, 33-38.]) Tmin = 0.649, Tmax = 0.985

  • 4952 measured reflections

  • 1806 independent reflections

  • 1599 reflections with I > 2σ(I)

  • Rint = 0.099

Refinement
  • R[F2 > 2σ(F2)] = 0.068

  • wR(F2) = 0.208

  • S = 1.23

  • 1806 reflections

  • 99 parameters

  • H atoms treated by a mixture of independent and constrained refinement

  • Δρmax = 0.30 e Å−3

  • Δρmin = −0.33 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N2—H2⋯N1i 0.80 (3) 2.37 (3) 3.129 (3) 159 (2)
Symmetry code: (i) x+1, y, z.

Data collection: COLLECT (Nonius, 2000[Nonius (2000). COLLECT. Nonius BV, Delft, The Netherlands.]); cell refinement: SCALEPACK (Otwinowski & Minor, 1997[Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307-326. New York: Academic Press.]); data reduction: DENZO (Otwinowski & Minor, 1997[Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307-326. New York: Academic Press.]) and SCALEPACK; program(s) used to solve structure: SIR92 (Altomare et al., 1993[Altomare, A., Cascarano, G., Giacovazzo, C. & Guagliardi, A. (1993). J. Appl. Cryst. 26, 343-350.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: X-SEED (Barbour, 2001[Barbour, L. J. (2001). J. Supramol. Chem. 1, 189-191.]); software used to prepare material for publication: WinGX (Farrugia, 1999[Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837-838.]).

Supporting information


Comment top

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.

Related literature top

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 crystal structure 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 top

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.

Refinement top

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.

Structure description top

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.

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 crystal structure 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).

Computing details top

Data collection: COLLECT (Nonius, 2000); cell refinement: 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).

Figures top
[Figure 1] Fig. 1. Perspective view of the asymmetric unit, showing the atom numbering. Displacement ellipsoids are at the 50% probablility level. H atoms are represented by circles of arbitrary size. Unlabelled atoms are related to labelled atoms by the symmetry operation -x, -y, -z.
[Figure 2] Fig. 2. The crystal packing, viewed along the a axis.
[Figure 3] Fig. 3. A fragment of the molecular packing, clearly showing H-bond interactions between adjacent molecules. [Symmetry code: (ii) x-1, y, z.].
1,1'-(Ethane-1,2-diyl)bis(1,4,7-triazonane) top
Crystal data top
C14H32N6Z = 1
Mr = 284.46F(000) = 158
Triclinic, P1Dx = 1.18 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 6.2732 (3) ÅCell parameters from 6758 reflections
b = 6.4988 (3) Åθ = 1.0–27.5°
c = 10.7152 (6) ŵ = 0.08 mm1
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
Data collection top
Bruker–Nonius KappaCCD
diffractometer
1806 independent reflections
Radiation source: fine-focus sealed tube1599 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.099
φ and ω scansθmax = 27.5°, θmin = 1.9°
Absorption correction: multi-scan
(SORTAV; Blessing, 1995)
h = 78
Tmin = 0.649, Tmax = 0.985k = 88
4952 measured reflectionsl = 1313
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.068Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.208H 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 parametersΔρmax = 0.30 e Å3
0 restraintsΔρmin = 0.33 e Å3
Crystal data top
C14H32N6γ = 110.410 (3)°
Mr = 284.46V = 400.45 (3) Å3
Triclinic, P1Z = 1
a = 6.2732 (3) ÅMo Kα radiation
b = 6.4988 (3) ŵ = 0.08 mm1
c = 10.7152 (6) ÅT = 150 K
α = 99.751 (2)°0.4 × 0.28 × 0.28 mm
β = 93.115 (2)°
Data collection top
Bruker–Nonius KappaCCD
diffractometer
1806 independent reflections
Absorption correction: multi-scan
(SORTAV; Blessing, 1995)
1599 reflections with I > 2σ(I)
Tmin = 0.649, Tmax = 0.985Rint = 0.099
4952 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0680 restraints
wR(F2) = 0.208H atoms treated by a mixture of independent and constrained refinement
S = 1.23Δρmax = 0.30 e Å3
1806 reflectionsΔρmin = 0.33 e Å3
99 parameters
Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
N10.1344 (3)0.5390 (3)0.32247 (17)0.0229 (4)
H10.145 (5)0.533 (5)0.233 (3)0.033 (7)*
N20.6399 (3)0.5507 (3)0.29452 (16)0.0202 (4)
H20.775 (5)0.583 (4)0.312 (2)0.019 (6)*
N30.1962 (3)0.1707 (3)0.15019 (15)0.0200 (4)
C10.3489 (3)0.6779 (3)0.4061 (2)0.0231 (5)
H1A0.36710.59780.47440.028*
H1B0.33280.8190.44750.028*
C20.5687 (3)0.7378 (3)0.3420 (2)0.0234 (5)
H2A0.54680.8080.26960.028*
H2B0.69450.85130.4040.028*
C30.5883 (3)0.4564 (3)0.15762 (18)0.0234 (5)
H3A0.73450.4730.12210.028*
H3B0.51670.54610.11680.028*
C40.4308 (3)0.2106 (3)0.12080 (18)0.0225 (5)
H4A0.42670.15750.02820.027*
H4B0.49540.12110.16640.027*
C50.1748 (3)0.1640 (3)0.28616 (18)0.0211 (5)
H5A0.3290.22240.33550.025*
H5B0.09660.00720.29550.025*
C60.0377 (3)0.3056 (3)0.33779 (19)0.0230 (5)
H6A0.12070.23660.29340.028*
H6B0.02930.30370.42960.028*
C70.0265 (4)0.0249 (3)0.06487 (18)0.0241 (5)
H7A0.11660.07410.10490.029*
H7B0.08490.14930.05280.029*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0170 (8)0.0243 (9)0.0240 (9)0.0054 (7)0.0015 (6)0.0006 (7)
N20.0140 (8)0.0237 (9)0.0189 (8)0.0049 (6)0.0007 (6)0.0013 (6)
N30.0168 (8)0.0211 (8)0.0152 (8)0.0016 (6)0.0000 (6)0.0021 (6)
C10.0182 (9)0.0242 (10)0.0229 (10)0.0068 (8)0.0025 (7)0.0037 (8)
C20.0190 (9)0.0193 (9)0.0276 (10)0.0033 (7)0.0038 (7)0.0009 (8)
C30.0199 (9)0.0266 (10)0.0183 (9)0.0033 (8)0.0038 (7)0.0010 (8)
C40.0205 (10)0.0246 (10)0.0181 (9)0.0061 (8)0.0024 (7)0.0028 (7)
C50.0209 (9)0.0214 (9)0.0166 (9)0.0034 (7)0.0007 (7)0.0018 (7)
C60.0174 (9)0.0243 (10)0.0226 (10)0.0028 (7)0.0043 (7)0.0016 (8)
C70.0231 (10)0.0193 (9)0.0205 (10)0.0007 (7)0.0025 (7)0.0014 (8)
Geometric parameters (Å, º) top
N1—C61.466 (3)C3—C41.526 (3)
N1—C11.475 (2)C3—H3A0.99
N1—H10.96 (3)C3—H3B0.99
N2—C21.460 (3)C4—H4A0.99
N2—C31.462 (2)C4—H4B0.99
N2—H20.80 (3)C5—C61.524 (3)
N3—C71.464 (2)C5—H5A0.99
N3—C41.464 (2)C5—H5B0.99
N3—C51.477 (2)C6—H6A0.99
C1—C21.531 (3)C6—H6B0.99
C1—H1A0.99C7—C7i1.525 (4)
C1—H1B0.99C7—H7A0.99
C2—H2A0.99C7—H7B0.99
C2—H2B0.99
C6—N1—C1114.96 (17)H3A—C3—H3B107.5
C6—N1—H1106.1 (17)N3—C4—C3113.41 (16)
C1—N1—H1114.6 (17)N3—C4—H4A108.9
C2—N2—C3117.19 (17)C3—C4—H4A108.9
C2—N2—H2111.5 (17)N3—C4—H4B108.9
C3—N2—H2106.5 (18)C3—C4—H4B108.9
C7—N3—C4112.85 (15)H4A—C4—H4B107.7
C7—N3—C5112.41 (15)N3—C5—C6109.75 (16)
C4—N3—C5112.25 (15)N3—C5—H5A109.7
N1—C1—C2116.37 (17)C6—C5—H5A109.7
N1—C1—H1A108.2N3—C5—H5B109.7
C2—C1—H1A108.2C6—C5—H5B109.7
N1—C1—H1B108.2H5A—C5—H5B108.2
C2—C1—H1B108.2N1—C6—C5113.78 (16)
H1A—C1—H1B107.3N1—C6—H6A108.8
N2—C2—C1115.49 (16)C5—C6—H6A108.8
N2—C2—H2A108.4N1—C6—H6B108.8
C1—C2—H2A108.4C5—C6—H6B108.8
N2—C2—H2B108.4H6A—C6—H6B107.7
C1—C2—H2B108.4N3—C7—C7i112.1 (2)
H2A—C2—H2B107.5N3—C7—H7A109.2
N2—C3—C4115.55 (17)C7i—C7—H7A109.2
N2—C3—H3A108.4N3—C7—H7B109.2
C4—C3—H3A108.4C7i—C7—H7B109.2
N2—C3—H3B108.4H7A—C7—H7B107.9
C4—C3—H3B108.4
C6—N1—C1—C2106.9 (2)C7—N3—C5—C697.75 (19)
C3—N2—C2—C1101.1 (2)C4—N3—C5—C6133.75 (17)
N1—C1—C2—N267.9 (2)C1—N1—C6—C571.3 (2)
C2—N2—C3—C4118.6 (2)N3—C5—C6—N156.6 (2)
C7—N3—C4—C3151.78 (17)C4—N3—C7—C7i77.7 (3)
C5—N3—C4—C379.9 (2)C5—N3—C7—C7i154.1 (2)
N2—C3—C4—N367.4 (2)
Symmetry code: (i) x, y, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N2—H2···N1ii0.80 (3)2.37 (3)3.129 (3)159 (2)
Symmetry code: (ii) x+1, y, z.

Experimental details

Crystal data
Chemical formulaC14H32N6
Mr284.46
Crystal system, space groupTriclinic, 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)
V3)400.45 (3)
Z1
Radiation typeMo Kα
µ (mm1)0.08
Crystal size (mm)0.4 × 0.28 × 0.28
Data collection
DiffractometerBruker–Nonius KappaCCD
Absorption correctionMulti-scan
(SORTAV; Blessing, 1995)
Tmin, Tmax0.649, 0.985
No. of measured, independent and
observed [I > 2σ(I)] reflections
4952, 1806, 1599
Rint0.099
(sin θ/λ)max1)0.650
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.068, 0.208, 1.23
No. of reflections1806
No. of parameters99
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)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).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N2—H2···N1i0.80 (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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