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Crystal structures of 2,5-di­azido-1,4-phenyl­ene di­acetate and 2,5-di­azido-1,4-phenyl­ene dibutyrate

aInstitute of Applied Synthetic Chemistry, Vienna University of Technology, Getreidemarkt 9/163, A-1060 Vienna, Austria, and bInstitute for Chemical Technologies and Analytics, Division of Structural Chemistry, Vienna University of Technology, Getreidemarkt 9/164-SC, A-1060 Vienna, Austria
*Correspondence e-mail: mweil@mail.zserv.tuwien.ac.at

Edited by H. Stoeckli-Evans, University of Neuchâtel, Switzerland (Received 11 June 2014; accepted 12 June 2014; online 23 June 2014)

The asymmetric units of the title compounds, C10H8N6O4, (I), and C14H16N6O4, (II), each contain half of the respective mol­ecule which is completed by inversion symmetry. The two molecules differ in the ester moiety (acetate versus butyrate) and the crystal symmetry is different, i.e. triclinic for (I) and monoclinic for (II). The di­azido­phenyl­ene moieties are essentially planar [maximum deviation of 0.0216 (7) Å for (I) and 0.0330 (14) Å for (II)], and the ester functionalities are almost perpendicular to these planes, making dihedral angles of 79.93 (3)° for (I) and 79.42 (6)° for (II). In the crystals of both (I) and (II), there are no significant inter­molecular inter­actions present.

1. Chemical context

In recent years, copper(I)-catalysed cyclo­addition of organic azides and alkynes towards 1,4-disubstituted triazoles attained immense inter­est in various fields of organic chemistry and became famous as the `cream of the crop' of click chemistry (Moses & Moorhouse, 2007[Moses, J. E. & Moorhouse, A. D. (2007). Chem. Soc. Rev. 36, 1249-1262.]). In materials chemistry, this kind of reaction is often applied for the synthesis of functional polymers (Qin et al., 2010[Qin, A., Lam, J. W. Y. & Tang, B. Z. (2010). Chem. Soc. Rev. 39, 2522-2544.]).

[Scheme 1]

The title compounds, (I)[link] and (II)[link], were synthesized to investigate their applicability in such polymerizations, viz. AA–BB polymerizations with dialkynes. The synthetic accessibility of the two compounds from inexpensive starting materials is remarkable, making them suitable for large scale preparation. However, their electron-deficient character represents a challenge to the polymerization parameters. The crystal structures of (I)[link] and (II)[link] are reported herein.

2. Structural commentary

The mol­ecular structures of (I)[link] and (II)[link] are displayed in Figs. 1[link] and 2[link], respectively. Both mol­ecules possess inversion symmetry. Although the two mol­ecules differ only in the ester moiety (acetate versus butyrate), the crystal symmetry is different, i.e. triclinic for (I)[link], with Z = 1, and monoclinic for (II)[link], with Z = 2. The di­azido­phenyl­ene moieties do not differ significantly from planarity, with a maximum deviation of 0.0216 (7) Å in (I)[link] and 0.0330 (14) Å in (II)[link], for the unsubstituted atom C3 in both cases. The azide groups, both in trans positions to each other, deviate slightly from a linear arrangement, with an N—N—N angle of 173.01 (9)° for (I)[link] and 172.59 (16)° for (II)[link]. The mean planes of the acetate [C—C(=O)—O)] and butyrate [C—C—C—C(=O)—O] groups are almost normal to the mean planes of the di­azido­phenyl­ene moieties, with a dihedral angle of 79.93 (3)° for (I)[link] and 79.42 (6)° for (II)[link].

[Figure 1]
Figure 1
The mol­ecular structure of compound (I)[link], showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 80% probability level. Unlabelled atoms are generated by the symmetry code (−x + 1, −y, −z).
[Figure 2]
Figure 2
The mol­ecular structure of compound (II)[link], showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 80% probability level. Unlabelled atoms are generated by the symmetry code (−x + 1, −y, −z).

3. Supra­molecular features

There are no notable features in terms of ππ stacking inter­actions or hydrogen bonding in either structure. The crystal packing of (I)[link] and (II)[link] seems to be dominated mainly by van der Waals forces (Figs. 3[link] and 4[link], respectively).

[Figure 3]
Figure 3
A view along [100] of the crystal packing of compound (I)[link]. Colour code: O red, C grey, N light-blue and H white.
[Figure 4]
Figure 4
A view along [010] of the crystal packing of compound (II)[link]. Colour code: O red, C grey, N light-blue and H white.

4. Database survey

In the Cambridge Structural Database (Version 5.35, last update February 2014; Allen, 2002[Allen, F. H. (2002). Acta Cryst. B58, 380-388.]) no structures of compounds containing a trans-di­azido­phenyl­ene entity are listed, making the two examples presented herein the only ones reported so far.

5. Synthesis and crystallization

Both target compounds were synthesized following a two-step protocol (Fig. 5[link]), previously published for 2,5-di­azido-1,4-phenyl­ene di­acetate by Moore et al. (1969[Moore, H. W., Shelden, H. R. & Shellhamer, D. F. (1969). J. Org. Chem. 34, 1999-2001.]). In view of the light sensitivity of the inter­mediate compound 2,5-di­azido­benzene-1,4-diol, all reactions were carried out under light protection.

[Figure 5]
Figure 5
Reaction scheme for the synthesis of the title compounds.

Preparation of 2,5-di­azido­benzene-1,4-diol: 1,4-benzo­quinone (10.81 g, 100.0 mmol, 1.0 equivalent) was dissolved in glacial acetic acid (100 ml, 1.0 M) and cooled to 288 K using an ice-water bath. NaN3 (14.3 g, 220 mol, 2.2 equivalents) was dissolved in water (44 ml, 5.0 M) and added to the cooled and stirred solution of 1,4-benzo­quinone in one portion. Stirring was stopped after 15 min and the flask was sealed and stored at 278 K overnight for crystallization. Vacuum filtration afforded a light-yellow solid, which was washed three times with water and dried in vacuo overnight to afford 2,5-di­azido­benzene-1,4-diol (yield: 6.60 g, 34.4 mmol, 69%). 1,4-Benzo­quinone serves as starting material and as oxidation reagent in this reaction, resulting in a theoretical molar yield of only half of the applied starting material (50 mmol).

Preparation of 2,5-di­azido-1,4-phenyl­ene di­acetate, (I)[link]: 2,5-di­azido­benzene-1,4-diol (1.92 g, 10.0 mmol) was added to preheated (313 K) acetic anhydride (100 ml, 0.1 M) in one portion and the reaction stirred until complete dissolution of the starting material. The reaction mixture was then allowed to cool to room temperature and stored overnight to allow 2,5-di­azido-1,4-phenyl­ene di­acetate to crystallize. Vacuum filtration afforded light-orange crystals of compound (I)[link], which were washed with water three time (yield: 1.73 g, 6.26 mmol, 63%). 1H NMR (CDCl3, 200 MHz): δ 6.89 (s, 2H), 2.33 (s, 6H); 13C NMR (CDCl3, 50 MHz): δ 168.3 (s), 140.0 (s), 129.3 (s), 115.3 (d), 20.4 (q).

Preparation of 2,5-di­azido-1,4-phenyl­ene dibutyrate, (II)[link]: 2,5-di­azido­benzene-1,4-diol (1.34 g, 7.0 mmol) was added to preheated (333 K) butyric anhydride (20 ml, 0.35 M) in one portion and the resulting suspension stirred for 45 min at this temperature. The reaction mixture was then allowed to cool to room temperature and stored for 5 days to allow 2,5-di­azido-1,4-phenyl­ene dibutyrate to crystallize. Vacuum filtration afforded yellow crystals of compound (II)[link], which were washed with water three times and with ethanol twice (yield: 814 mg, 2.45 mmol, 35%). 1H NMR (CDCl3, 200 MHz): δ 6.88 (s, 2H), 2.57 (t, J = 7.4 Hz, 4H), 1.80 (sext, J = 7.4 Hz, 4H), 1.05 (t, J = 7.4 Hz, 6H); 13C NMR (CDCl3, 50 MHz): δ 171.1 (s), 140.0 (s), 129.3 (s), 115.3 (d), 35.6 (t), 18.3 (t), 13.6 (q).

6. Refinement

For both structures, (I)[link] and (II)[link], the H atoms were included in calculated positions and treated as riding atoms, with C—H = 0.96 Å and Uiso(H) = 1.2Ueq(C).[link]

Table 1
Experimental details

  (I) (II)
Crystal data
Chemical formula C10H8N6O4 C14H16N6O4
Mr 276.2 332.3
Crystal system, space group Triclinic, P[\overline{1}] Monoclinic, P21/n
Temperature (K) 100 100
a, b, c (Å) 5.4293 (6), 5.5678 (6), 10.4945 (12) 11.5875 (19), 5.1485 (8), 14.327 (2)
α, β, γ (°) 101.508 (3), 104.544 (3), 97.057 (3) 90, 108.496 (5), 90
V3) 295.86 (6) 810.6 (2)
Z 1 2
Radiation type Mo Kα Mo Kα
μ (mm−1) 0.12 0.10
Crystal size (mm) 0.65 × 0.55 × 0.25 0.65 × 0.25 × 0.08
 
Data collection
Diffractometer Bruker Kappa APEXII CCD Bruker Kappa APEXII CCD
Absorption correction Multi-scan (SADABS; Bruker, 2013[Bruker (2013). APEX2, SAINT-Plus and SADABS. Bruker AXS Inc. Madison, Wisconsin, USA.]) Multi-scan (SADABS; Bruker, 2013[Bruker (2013). APEX2, SAINT-Plus and SADABS. Bruker AXS Inc. Madison, Wisconsin, USA.])
Tmin, Tmax 0.92, 0.97 0.97, 0.99
No. of measured, independent and observed [I > 3σ(I)] reflections 15989, 2182, 1983 17268, 1781, 1211
Rint 0.037 0.043
(sin θ/λ)max−1) 0.764 0.662
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.034, 0.056, 3.22 0.042, 0.048, 2.15
No. of reflections 2182 1781
No. of parameters 91 109
H-atom treatment H-atom parameters constrained H-atom parameters constrained
Δρmax, Δρmin (e Å−3) 0.46, −0.23 0.26, −0.23
Computer programs: APEX2 and SAINT-Plus (Bruker, 2013[Bruker (2013). APEX2, SAINT-Plus and SADABS. Bruker AXS Inc. Madison, Wisconsin, USA.]), SUPERFLIP (Palatinus & Chapuis, 2007[Palatinus, L. & Chapuis, G. (2007). J. Appl. Cryst. 40, 786-790.]), JANA2006 (Petříček, et al., 2014[Petříček, V., Dušek, M. & Palatinus, L. (2014). Z. Kristallogr. 229, 345-352.]), Mercury (Macrae et al., 2008[Macrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466-470.]) and publCIF (Westrip, 2010[Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.]).

Supporting information


Computing details top

For both compounds, data collection: APEX2 (Bruker, 2013); cell refinement: SAINT-Plus (Bruker, 2013); data reduction: SAINT-Plus (Bruker, 2013); program(s) used to solve structure: SUPERFLIP (Palatinus & Chapuis, 2007); program(s) used to refine structure: JANA2006 (Petříček, et al., 2014); molecular graphics: Mercury (Macrae et al., 2008); software used to prepare material for publication: publCIF (Westrip, 2010).

(I) 2,5-Diazido-1,4-phenylene diacetate top
Crystal data top
C10H8N6O4V = 295.86 (6) Å3
Mr = 276.2Z = 1
Triclinic, P1F(000) = 142
Hall symbol: -P 1Dx = 1.550 Mg m3
a = 5.4293 (6) ÅMo Kα radiation, λ = 0.71073 Å
b = 5.5678 (6) Åθ = 3.8–32.8°
c = 10.4945 (12) ŵ = 0.12 mm1
α = 101.508 (3)°T = 100 K
β = 104.544 (3)°Irregular, light-orange
γ = 97.057 (3)°0.65 × 0.55 × 0.25 mm
Data collection top
Bruker Kappa APEXII CCD
diffractometer
2182 independent reflections
Radiation source: X-ray tube1983 reflections with I > 3σ(I)
Graphite monochromatorRint = 0.037
ω and φ scansθmax = 32.9°, θmin = 2.1°
Absorption correction: multi-scan
(SADABS; Bruker, 2013)
h = 88
Tmin = 0.92, Tmax = 0.97k = 88
15989 measured reflectionsl = 1516
Refinement top
Refinement on F16 constraints
R[F > 3σ(F)] = 0.034H-atom parameters constrained
wR(F) = 0.056Weighting scheme based on measured s.u.'s w = 1/(σ2(F) + 0.0001F2)
S = 3.22(Δ/σ)max = 0.011
2182 reflectionsΔρmax = 0.46 e Å3
91 parametersΔρmin = 0.23 e Å3
0 restraints
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O10.25671 (10)0.01146 (10)0.20279 (5)0.01189 (16)
O20.59540 (11)0.28134 (10)0.35546 (6)0.01772 (18)
N10.36886 (13)0.27117 (12)0.19926 (6)0.0141 (2)
N20.19623 (12)0.39755 (11)0.19328 (6)0.01377 (19)
N30.04446 (14)0.51922 (13)0.19896 (8)0.0208 (2)
C10.42743 (13)0.13837 (12)0.09681 (7)0.0106 (2)
C20.38596 (13)0.01109 (13)0.10373 (7)0.01038 (19)
C30.31388 (13)0.14839 (12)0.00901 (7)0.0108 (2)
C40.38466 (14)0.15794 (13)0.33011 (7)0.0119 (2)
C50.22479 (16)0.13357 (15)0.42495 (7)0.0174 (2)
H1c30.1856110.2507210.0160230.013*
H1c50.0542710.1622260.386060.0208*
H2c50.2134840.0311710.4403610.0208*
H3c50.3036270.2539620.5095250.0208*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0113 (3)0.0152 (2)0.0096 (2)0.00109 (19)0.00522 (18)0.00195 (18)
O20.0164 (3)0.0197 (3)0.0148 (3)0.0021 (2)0.0057 (2)0.0004 (2)
N10.0169 (3)0.0155 (3)0.0139 (3)0.0069 (2)0.0072 (2)0.0064 (2)
N20.0161 (3)0.0132 (3)0.0137 (3)0.0024 (2)0.0056 (2)0.0056 (2)
N30.0214 (4)0.0201 (3)0.0276 (4)0.0089 (3)0.0118 (3)0.0119 (3)
C10.0113 (3)0.0107 (3)0.0096 (3)0.0016 (2)0.0032 (2)0.0021 (2)
C20.0105 (3)0.0116 (3)0.0091 (3)0.0012 (2)0.0042 (2)0.0011 (2)
C30.0106 (3)0.0115 (3)0.0107 (3)0.0027 (2)0.0040 (2)0.0018 (2)
C40.0144 (3)0.0124 (3)0.0102 (3)0.0039 (2)0.0049 (2)0.0028 (2)
C50.0186 (4)0.0228 (4)0.0129 (3)0.0030 (3)0.0091 (3)0.0037 (3)
Geometric parameters (Å, º) top
O1—C21.3924 (10)C1—C31.3943 (11)
O1—C41.3758 (8)C2—C31.3810 (11)
O2—C41.1971 (9)C3—H1c30.96
N1—N21.2456 (10)C4—C51.4904 (12)
N1—C11.4167 (10)C5—H1c50.96
N2—N31.1269 (10)C5—H2c50.96
C1—C2i1.3944 (11)C5—H3c50.96
C2—O1—C4116.60 (5)C2—C3—H1c3120
N2—N1—C1115.40 (7)O1—C4—O2122.32 (7)
N1—N2—N3173.01 (9)O1—C4—C5110.16 (6)
N1—C1—C2i116.58 (7)O2—C4—C5127.51 (6)
N1—C1—C3124.83 (7)C4—C5—H1c5109.47
C2i—C1—C3118.59 (7)C4—C5—H2c5109.47
O1—C2—C1i119.80 (7)C4—C5—H3c5109.47
O1—C2—C3118.66 (7)H1c5—C5—H2c5109.47
C1i—C2—C3121.42 (7)H1c5—C5—H3c5109.47
C1—C3—C2120.00 (7)H2c5—C5—H3c5109.47
C1—C3—H1c3120
Symmetry code: (i) x+1, y, z.
(II) 2,5-Diazido-1,4-phenylene dibutyrate top
Crystal data top
C14H16N6O4F(000) = 348
Mr = 332.3Dx = 1.361 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 7352 reflections
a = 11.5875 (19) Åθ = 2.7–27.0°
b = 5.1485 (8) ŵ = 0.10 mm1
c = 14.327 (2) ÅT = 100 K
β = 108.496 (5)°Rod, light-yellow
V = 810.6 (2) Å30.65 × 0.25 × 0.08 mm
Z = 2
Data collection top
Bruker Kappa APEXII CCD
diffractometer
1781 independent reflections
Radiation source: X-ray tube1211 reflections with I > 3σ(I)
Graphite monochromatorRint = 0.043
ω and φ scansθmax = 28.1°, θmin = 2.0°
Absorption correction: multi-scan
(SADABS; Bruker, 2013)
h = 1314
Tmin = 0.97, Tmax = 0.99k = 66
17268 measured reflectionsl = 1718
Refinement top
Refinement on F32 constraints
R[F > 3σ(F)] = 0.042H-atom parameters constrained
wR(F) = 0.048Weighting scheme based on measured s.u.'s w = 1/(σ2(F) + 0.0001F2)
S = 2.15(Δ/σ)max = 0.005
1781 reflectionsΔρmax = 0.26 e Å3
109 parametersΔρmin = 0.23 e Å3
0 restraints
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O10.28390 (9)0.01294 (17)0.04347 (7)0.0217 (4)
O20.33949 (10)0.32997 (19)0.14715 (7)0.0269 (4)
N10.68785 (12)0.3626 (2)0.07891 (8)0.0224 (5)
N20.67449 (11)0.5255 (2)0.13953 (9)0.0225 (5)
N30.67447 (13)0.6825 (2)0.19484 (9)0.0296 (5)
C10.58925 (14)0.1863 (2)0.04072 (10)0.0177 (5)
C20.39470 (14)0.0013 (3)0.02402 (10)0.0181 (5)
C30.48219 (14)0.1877 (3)0.06446 (10)0.0190 (5)
C40.26254 (15)0.1781 (3)0.10334 (10)0.0214 (6)
C50.13432 (15)0.1622 (3)0.10373 (11)0.0265 (6)
C60.10348 (15)0.3423 (3)0.17548 (11)0.0303 (6)
C70.02989 (17)0.3320 (4)0.16734 (13)0.0411 (7)
H1c30.4689820.316480.1084590.0228*
H1c50.0800470.1941430.0385680.0318*
H2c50.1160860.0134960.1166560.0318*
H1c60.1520490.2983910.2413530.0364*
H2c60.1250930.516980.1644670.0364*
H1c70.0451580.4501160.213940.0493*
H2c70.0507260.1588010.1809580.0493*
H3c70.0783760.3806370.1019730.0493*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0263 (7)0.0157 (5)0.0273 (6)0.0017 (5)0.0143 (5)0.0033 (4)
O20.0324 (7)0.0217 (6)0.0303 (6)0.0055 (5)0.0150 (5)0.0053 (5)
N10.0290 (9)0.0153 (6)0.0251 (7)0.0013 (6)0.0114 (6)0.0036 (6)
N20.0264 (9)0.0159 (6)0.0247 (7)0.0015 (6)0.0072 (6)0.0037 (6)
N30.0397 (10)0.0189 (7)0.0297 (7)0.0022 (6)0.0101 (7)0.0052 (6)
C10.0231 (10)0.0108 (7)0.0194 (7)0.0002 (6)0.0069 (7)0.0020 (6)
C20.0218 (10)0.0148 (7)0.0208 (8)0.0040 (7)0.0109 (7)0.0048 (6)
C30.0283 (10)0.0112 (7)0.0189 (8)0.0023 (6)0.0095 (7)0.0016 (6)
C40.0309 (11)0.0135 (7)0.0225 (8)0.0025 (7)0.0124 (7)0.0029 (6)
C50.0286 (11)0.0212 (8)0.0320 (9)0.0005 (7)0.0131 (7)0.0019 (7)
C60.0338 (11)0.0259 (9)0.0356 (9)0.0051 (8)0.0173 (8)0.0004 (7)
C70.0376 (12)0.0516 (12)0.0386 (11)0.0118 (9)0.0184 (9)0.0030 (9)
Geometric parameters (Å, º) top
O1—C21.399 (2)C4—C51.490 (3)
O1—C41.3780 (19)C5—C61.509 (2)
O2—C41.2023 (17)C5—H1c50.96
N1—N21.2518 (18)C5—H2c50.96
N1—C11.4257 (18)C6—C71.513 (3)
N2—N31.1318 (18)C6—H1c60.96
C1—C2i1.392 (2)C6—H2c60.96
C1—C31.387 (2)C7—H1c70.96
C2—C31.3825 (19)C7—H2c70.96
C3—H1c30.96C7—H3c70.96
C2—O1—C4116.81 (11)C4—C5—H2c5109.47
N2—N1—C1115.62 (14)C6—C5—H1c5109.47
N1—N2—N3172.59 (16)C6—C5—H2c5109.47
N1—C1—C2i115.94 (15)H1c5—C5—H2c5103.47
N1—C1—C3124.96 (13)C5—C6—C7112.50 (13)
C2i—C1—C3119.09 (13)C5—C6—H1c6109.47
O1—C2—C1i119.18 (12)C5—C6—H2c6109.47
O1—C2—C3118.96 (13)C7—C6—H1c6109.47
C1i—C2—C3121.71 (15)C7—C6—H2c6109.47
C1—C3—C2119.20 (14)H1c6—C6—H2c6106.26
C1—C3—H1c3120.4C6—C7—H1c7109.47
C2—C3—H1c3120.4C6—C7—H2c7109.47
O1—C4—O2122.63 (16)C6—C7—H3c7109.47
O1—C4—C5109.84 (12)H1c7—C7—H2c7109.47
O2—C4—C5127.53 (15)H1c7—C7—H3c7109.47
C4—C5—C6114.88 (12)H2c7—C7—H3c7109.47
C4—C5—H1c5109.47
Symmetry code: (i) x+1, y, z.
 

Acknowledgements

The X-ray centre of the Vienna University of Technology is acknowledged for providing access to the single-crystal diffractometer.

References

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