organic compounds
5-(4-Hexyl-1H-1,2,3-triazol-1-yl)-2,1,3-benzoxadiazole
aAlberta Glycomics Centre, Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada, and bX-ray Crystallography Laboratory, Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada
*Correspondence e-mail: michael.ferguson@ualberta.ca
The title compound, C14H17N5O, a 1,2,3-triazole derivative of benzoxadiazole (C14H17N5O), was synthesized via Cu-catalysed azide–alkyne cycloaddition (CuAAC) from the corresponding n-octyne and 4-azidobenzoxadiazole. The benzoxadiazole and triazole rings show a roughly planar orientation [dihedral angle between the ring planes = 12.18 (5)°]. The alkane chain adopts a zigzag conformation, which deviates from the central triazole ring by 20.89 (6)°. These two torsion angles result in an overall twist to the structure, with a dihedral angle of 32.86 (7)° between the benzoxadiazole group and the hexyl chain. The features C—H⋯N hydrogen bonds leading to chains propagating along [2-10] and offset parallel stacking interactions of the triazole and benzoxadiazole rings. The centroid of the extended π-system formed by the benzoxadiazole and triazole rings (14 atoms total) was calculated; the centroid–centroid distance was 4.179 Å, interplanar separation was 3.243 Å, and the resulting offset was 2.636 Å.
Related literature
For the synthesis of the title compound and related benzoxadiazole analogs, see: Key & Cairo (2011). For computational studies of the absorption and fluorescence properties of this series of compounds, see: Brown et al. (2012). For structures with 1-aryl-substituted 1,2,3-triazole rings, see: Costa et al. (2006). For the use of fluorophores as chemical or biological probes, see: Cairo et al. (2010); Lavis & Raines (2008). For related benzoxadiazole structures, see: Key et al. (2012a,b). For triazole-substituted coumarin derivatives, see: Key et al. (2009).
Experimental
Crystal data
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Refinement
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Data collection: APEX2 (Bruker, 2008); cell SAINT (Bruker, 2008); data reduction: SAINT; program(s) used to solve structure: SHELXD (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.
Supporting information
10.1107/S1600536812041815/mw2081sup1.cif
contains datablocks I, global. DOI:Supporting information file. DOI: 10.1107/S1600536812041815/mw2081Isup2.cdx
Structure factors: contains datablock I. DOI: 10.1107/S1600536812041815/mw2081Isup3.hkl
Supporting information file. DOI: 10.1107/S1600536812041815/mw2081Isup4.cml
4-Azidobenzoxadiazole (30 mg, 0.19 mmol, 1 equiv) was dissolved in 1:1 water/methanol (5 mL), followed by addition of n-octyne (0.14 mL, 0.93 mmol, 5 equiv). Copper sulfate (6 mg, 0.037 mmol, 0.2 equiv) and ascorbic acid (10 mg, 0.056 mmol, 0.3 equiv) were then added to the mixture. The reaction was allowed to stir at room temperature for 6 h. The reaction was quenched with distilled water, and the crude product was extracted with chloroform, followed by water and brine washes. The organic layer was then dried over MgSO4 and concentrated in vacuo. Purification was performed by δ 8.19 (dd, 1H, 4J = 3.8 Hz, 4J = 1.84 Hz), 8.06 (m, 2H), 7.91 (s, 1H), 2.85 (t, 2H, 3J = 8.0 Hz), 1.77 (m, 2H), 1.31–1.47 (m, 6H),0.91 (m, 3H); 13C NMR (100 MHz, CDCl3): δ150.5, 149.0, 148.4, 139.1, 126.8, 119.1, 118.9, 104.5, 31.8, 29.4, 29.1, 25.9, 22.8, 14.3; IR (microscope): ν = 3147, 3114, 3095, 3059, 2956, 2929, 2857, 1637, 1540 cm-1; ES-HRMS calculated for C14H18N5O [M+H]: 272.1506; observed: 272.1513. Rf = 0.51 (1:3 EtOAc/hexanes).
(EtOAc/hexanes). The product was obtained as white crystals (25 mg, 50%). m.p. 113.2–115.4 °C; 1H NMR (400 MHz, CDCl3):Although the hydrogen atoms could have been discerned in the difference
all H atoms were generated in idealized positions and refined using a riding model with fixed C—H distances (Caryl = 0.95 Å, Cmethyl = 0.98 Å, Cmethylene = 0.99 Å) and with Uiso(H) = 1.2Ueq(C).Data collection: APEX2 (Bruker, 2008); cell
SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); program(s) used to solve structure: SHELXD (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).C14H17N5O | Z = 2 |
Mr = 271.33 | F(000) = 288 |
Triclinic, P1 | Dx = 1.315 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 5.3604 (8) Å | Cell parameters from 5179 reflections |
b = 7.8585 (11) Å | θ = 2.5–27.5° |
c = 16.357 (2) Å | µ = 0.09 mm−1 |
α = 87.4656 (17)° | T = 173 K |
β = 86.2519 (16)° | Plate, colourless |
γ = 85.6240 (17)° | 1.02 × 0.35 × 0.03 mm |
V = 685.04 (17) Å3 |
Bruker APEXII CCD diffractometer | 3120 independent reflections |
Radiation source: fine-focus sealed tube | 2568 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.013 |
ω scans | θmax = 27.6°, θmin = 2.5° |
Absorption correction: multi-scan (SADABS; Bruker, 2008) | h = −6→6 |
Tmin = 0.915, Tmax = 0.997 | k = −10→10 |
6114 measured reflections | l = −21→21 |
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)] = 0.036 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.099 | H-atom parameters constrained |
S = 1.04 | w = 1/[σ2(Fo2) + (0.0495P)2 + 0.1216P] where P = (Fo2 + 2Fc2)/3 |
3120 reflections | (Δ/σ)max = 0.002 |
181 parameters | Δρmax = 0.20 e Å−3 |
0 restraints | Δρmin = −0.22 e Å−3 |
C14H17N5O | γ = 85.6240 (17)° |
Mr = 271.33 | V = 685.04 (17) Å3 |
Triclinic, P1 | Z = 2 |
a = 5.3604 (8) Å | Mo Kα radiation |
b = 7.8585 (11) Å | µ = 0.09 mm−1 |
c = 16.357 (2) Å | T = 173 K |
α = 87.4656 (17)° | 1.02 × 0.35 × 0.03 mm |
β = 86.2519 (16)° |
Bruker APEXII CCD diffractometer | 3120 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2008) | 2568 reflections with I > 2σ(I) |
Tmin = 0.915, Tmax = 0.997 | Rint = 0.013 |
6114 measured reflections |
R[F2 > 2σ(F2)] = 0.036 | 0 restraints |
wR(F2) = 0.099 | H-atom parameters constrained |
S = 1.04 | Δρmax = 0.20 e Å−3 |
3120 reflections | Δρmin = −0.22 e Å−3 |
181 parameters |
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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 | ||
O | 0.41878 (17) | 0.07628 (11) | 0.71631 (5) | 0.0427 (2) | |
N1 | 0.2106 (2) | 0.18420 (14) | 0.73699 (6) | 0.0420 (3) | |
N2 | 0.44587 (19) | 0.04944 (13) | 0.63299 (6) | 0.0359 (2) | |
N3 | −0.10674 (16) | 0.28627 (11) | 0.42563 (5) | 0.0269 (2) | |
N4 | −0.33882 (18) | 0.36159 (13) | 0.41382 (6) | 0.0351 (2) | |
N5 | −0.36564 (18) | 0.36862 (13) | 0.33489 (6) | 0.0370 (2) | |
C1 | 0.1091 (2) | 0.22446 (14) | 0.66688 (7) | 0.0316 (2) | |
C2 | 0.2550 (2) | 0.14071 (13) | 0.60238 (7) | 0.0287 (2) | |
C3 | 0.1873 (2) | 0.15961 (13) | 0.51960 (6) | 0.0278 (2) | |
H3 | 0.2835 | 0.1041 | 0.4763 | 0.033* | |
C4 | −0.0229 (2) | 0.26178 (13) | 0.50634 (6) | 0.0259 (2) | |
C5 | −0.1709 (2) | 0.34929 (13) | 0.57088 (7) | 0.0299 (2) | |
H5 | −0.3147 | 0.4207 | 0.5575 | 0.036* | |
C6 | −0.1098 (2) | 0.33215 (14) | 0.64981 (7) | 0.0336 (3) | |
H6 | −0.2082 | 0.3892 | 0.6921 | 0.040* | |
C7 | 0.0134 (2) | 0.24553 (14) | 0.35268 (6) | 0.0284 (2) | |
H7 | 0.1772 | 0.1920 | 0.3437 | 0.034* | |
C8 | −0.1520 (2) | 0.29817 (14) | 0.29511 (7) | 0.0306 (2) | |
C9 | −0.1308 (2) | 0.29097 (17) | 0.20385 (7) | 0.0374 (3) | |
H9A | −0.2088 | 0.3989 | 0.1804 | 0.045* | |
H9B | −0.2280 | 0.1970 | 0.1878 | 0.045* | |
C10 | 0.1352 (2) | 0.26410 (16) | 0.16610 (7) | 0.0343 (3) | |
H10A | 0.2127 | 0.1538 | 0.1872 | 0.041* | |
H10B | 0.2354 | 0.3561 | 0.1827 | 0.041* | |
C11 | 0.1402 (2) | 0.26410 (15) | 0.07277 (7) | 0.0340 (3) | |
H11A | 0.0493 | 0.1669 | 0.0568 | 0.041* | |
H11B | 0.0490 | 0.3704 | 0.0526 | 0.041* | |
C12 | 0.4022 (2) | 0.25125 (16) | 0.03056 (7) | 0.0340 (3) | |
H12A | 0.4936 | 0.3484 | 0.0462 | 0.041* | |
H12B | 0.4938 | 0.1447 | 0.0503 | 0.041* | |
C13 | 0.4010 (2) | 0.25185 (16) | −0.06240 (7) | 0.0379 (3) | |
H13A | 0.3132 | 0.1529 | −0.0781 | 0.045* | |
H13B | 0.3055 | 0.3570 | −0.0819 | 0.045* | |
C14 | 0.6621 (3) | 0.24356 (19) | −0.10491 (8) | 0.0466 (3) | |
H14A | 0.6491 | 0.2458 | −0.1644 | 0.056* | |
H14B | 0.7560 | 0.1377 | −0.0874 | 0.056* | |
H14C | 0.7497 | 0.3418 | −0.0903 | 0.056* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O | 0.0479 (5) | 0.0486 (5) | 0.0312 (4) | 0.0037 (4) | −0.0081 (4) | −0.0020 (4) |
N1 | 0.0476 (6) | 0.0462 (6) | 0.0318 (5) | 0.0020 (5) | −0.0039 (5) | −0.0046 (4) |
N2 | 0.0388 (6) | 0.0387 (5) | 0.0302 (5) | −0.0004 (4) | −0.0060 (4) | −0.0015 (4) |
N3 | 0.0223 (4) | 0.0292 (4) | 0.0283 (5) | 0.0012 (3) | 0.0008 (3) | −0.0011 (3) |
N4 | 0.0250 (5) | 0.0441 (6) | 0.0348 (5) | 0.0057 (4) | −0.0011 (4) | −0.0015 (4) |
N5 | 0.0283 (5) | 0.0477 (6) | 0.0336 (5) | 0.0047 (4) | −0.0009 (4) | −0.0003 (4) |
C1 | 0.0374 (6) | 0.0312 (6) | 0.0266 (5) | −0.0057 (5) | 0.0007 (4) | −0.0031 (4) |
C2 | 0.0288 (6) | 0.0261 (5) | 0.0314 (5) | −0.0036 (4) | −0.0010 (4) | −0.0007 (4) |
C3 | 0.0275 (5) | 0.0285 (5) | 0.0272 (5) | −0.0017 (4) | 0.0023 (4) | −0.0037 (4) |
C4 | 0.0263 (5) | 0.0259 (5) | 0.0256 (5) | −0.0053 (4) | 0.0007 (4) | −0.0010 (4) |
C5 | 0.0279 (6) | 0.0280 (5) | 0.0328 (6) | 0.0004 (4) | 0.0040 (4) | −0.0028 (4) |
C6 | 0.0378 (6) | 0.0323 (6) | 0.0299 (6) | −0.0016 (5) | 0.0063 (5) | −0.0062 (4) |
C7 | 0.0241 (5) | 0.0334 (6) | 0.0268 (5) | 0.0008 (4) | 0.0018 (4) | −0.0011 (4) |
C8 | 0.0247 (5) | 0.0354 (6) | 0.0312 (6) | −0.0013 (4) | −0.0007 (4) | 0.0013 (4) |
C9 | 0.0299 (6) | 0.0539 (7) | 0.0275 (6) | 0.0017 (5) | −0.0039 (4) | 0.0031 (5) |
C10 | 0.0313 (6) | 0.0438 (7) | 0.0271 (5) | 0.0021 (5) | −0.0035 (4) | 0.0002 (5) |
C11 | 0.0325 (6) | 0.0416 (6) | 0.0272 (5) | 0.0018 (5) | −0.0043 (4) | 0.0010 (4) |
C12 | 0.0333 (6) | 0.0410 (6) | 0.0274 (5) | 0.0009 (5) | −0.0034 (4) | −0.0017 (4) |
C13 | 0.0390 (7) | 0.0468 (7) | 0.0275 (6) | −0.0001 (5) | −0.0031 (5) | −0.0009 (5) |
C14 | 0.0459 (8) | 0.0612 (9) | 0.0326 (6) | −0.0065 (6) | 0.0041 (5) | −0.0064 (6) |
O—N1 | 1.3821 (14) | C8—C9 | 1.4929 (15) |
O—N2 | 1.3849 (12) | C9—C10 | 1.5195 (16) |
N1—C1 | 1.3170 (15) | C9—H9A | 0.9900 |
N2—C2 | 1.3173 (14) | C9—H9B | 0.9900 |
N3—C7 | 1.3576 (13) | C10—C11 | 1.5251 (15) |
N3—N4 | 1.3581 (13) | C10—H10A | 0.9900 |
N3—C4 | 1.4227 (13) | C10—H10B | 0.9900 |
N4—N5 | 1.3067 (13) | C11—C12 | 1.5223 (16) |
N5—C8 | 1.3709 (14) | C11—H11A | 0.9900 |
C1—C2 | 1.4257 (15) | C11—H11B | 0.9900 |
C1—C6 | 1.4288 (16) | C12—C13 | 1.5207 (15) |
C2—C3 | 1.4231 (15) | C12—H12A | 0.9900 |
C3—C4 | 1.3563 (15) | C12—H12B | 0.9900 |
C3—H3 | 0.9500 | C13—C14 | 1.5200 (17) |
C4—C5 | 1.4451 (15) | C13—H13A | 0.9900 |
C5—C6 | 1.3511 (16) | C13—H13B | 0.9900 |
C5—H5 | 0.9500 | C14—H14A | 0.9800 |
C6—H6 | 0.9500 | C14—H14B | 0.9800 |
C7—C8 | 1.3648 (15) | C14—H14C | 0.9800 |
C7—H7 | 0.9500 | ||
N1—O—N2 | 112.30 (8) | C10—C9—H9A | 108.5 |
C1—N1—O | 104.60 (9) | C8—C9—H9B | 108.5 |
C2—N2—O | 104.44 (9) | C10—C9—H9B | 108.5 |
C7—N3—N4 | 110.32 (9) | H9A—C9—H9B | 107.5 |
C7—N3—C4 | 129.66 (9) | C9—C10—C11 | 111.55 (9) |
N4—N3—C4 | 120.02 (9) | C9—C10—H10A | 109.3 |
N5—N4—N3 | 107.10 (9) | C11—C10—H10A | 109.3 |
N4—N5—C8 | 109.41 (9) | C9—C10—H10B | 109.3 |
N1—C1—C2 | 109.28 (10) | C11—C10—H10B | 109.3 |
N1—C1—C6 | 130.17 (11) | H10A—C10—H10B | 108.0 |
C2—C1—C6 | 120.55 (10) | C12—C11—C10 | 114.34 (9) |
N2—C2—C3 | 129.02 (10) | C12—C11—H11A | 108.7 |
N2—C2—C1 | 109.39 (10) | C10—C11—H11A | 108.7 |
C3—C2—C1 | 121.58 (10) | C12—C11—H11B | 108.7 |
C4—C3—C2 | 115.86 (9) | C10—C11—H11B | 108.7 |
C4—C3—H3 | 122.1 | H11A—C11—H11B | 107.6 |
C2—C3—H3 | 122.1 | C13—C12—C11 | 113.10 (9) |
C3—C4—N3 | 119.77 (9) | C13—C12—H12A | 109.0 |
C3—C4—C5 | 123.22 (10) | C11—C12—H12A | 109.0 |
N3—C4—C5 | 117.01 (9) | C13—C12—H12B | 109.0 |
C6—C5—C4 | 121.65 (10) | C11—C12—H12B | 109.0 |
C6—C5—H5 | 119.2 | H12A—C12—H12B | 107.8 |
C4—C5—H5 | 119.2 | C14—C13—C12 | 113.29 (10) |
C5—C6—C1 | 117.13 (10) | C14—C13—H13A | 108.9 |
C5—C6—H6 | 121.4 | C12—C13—H13A | 108.9 |
C1—C6—H6 | 121.4 | C14—C13—H13B | 108.9 |
N3—C7—C8 | 105.12 (9) | C12—C13—H13B | 108.9 |
N3—C7—H7 | 127.4 | H13A—C13—H13B | 107.7 |
C8—C7—H7 | 127.4 | C13—C14—H14A | 109.5 |
C7—C8—N5 | 108.05 (10) | C13—C14—H14B | 109.5 |
C7—C8—C9 | 131.26 (10) | H14A—C14—H14B | 109.5 |
N5—C8—C9 | 120.69 (10) | C13—C14—H14C | 109.5 |
C8—C9—C10 | 115.02 (9) | H14A—C14—H14C | 109.5 |
C8—C9—H9A | 108.5 | H14B—C14—H14C | 109.5 |
N2—O—N1—C1 | −0.10 (12) | C7—N3—C4—C5 | 167.55 (10) |
N1—O—N2—C2 | 0.04 (12) | N4—N3—C4—C5 | −12.02 (14) |
C7—N3—N4—N5 | −0.01 (12) | C3—C4—C5—C6 | −1.06 (17) |
C4—N3—N4—N5 | 179.64 (9) | N3—C4—C5—C6 | 178.83 (10) |
N3—N4—N5—C8 | 0.00 (13) | C4—C5—C6—C1 | 0.44 (16) |
O—N1—C1—C2 | 0.11 (12) | N1—C1—C6—C5 | −179.58 (12) |
O—N1—C1—C6 | −179.94 (11) | C2—C1—C6—C5 | 0.36 (16) |
O—N2—C2—C3 | −179.31 (10) | N4—N3—C7—C8 | 0.01 (12) |
O—N2—C2—C1 | 0.03 (12) | C4—N3—C7—C8 | −179.59 (10) |
N1—C1—C2—N2 | −0.09 (13) | N3—C7—C8—N5 | −0.01 (12) |
C6—C1—C2—N2 | 179.96 (10) | N3—C7—C8—C9 | 179.38 (12) |
N1—C1—C2—C3 | 179.30 (10) | N4—N5—C8—C7 | 0.01 (13) |
C6—C1—C2—C3 | −0.65 (16) | N4—N5—C8—C9 | −179.46 (10) |
N2—C2—C3—C4 | 179.35 (11) | C7—C8—C9—C10 | −18.02 (19) |
C1—C2—C3—C4 | 0.08 (15) | N5—C8—C9—C10 | 161.30 (11) |
C2—C3—C4—N3 | −179.14 (9) | C8—C9—C10—C11 | −178.16 (10) |
C2—C3—C4—C5 | 0.75 (15) | C9—C10—C11—C12 | 175.60 (10) |
C7—N3—C4—C3 | −12.56 (16) | C10—C11—C12—C13 | −179.91 (10) |
N4—N3—C4—C3 | 167.88 (9) | C11—C12—C13—C14 | 178.54 (11) |
D—H···A | D—H | H···A | D···A | D—H···A |
C3—H3···N2i | 0.95 | 2.52 | 3.4674 (15) | 177 |
C5—H5···N4ii | 0.95 | 2.46 | 3.3445 (15) | 154 |
Symmetry codes: (i) −x+1, −y, −z+1; (ii) −x−1, −y+1, −z+1. |
Experimental details
Crystal data | |
Chemical formula | C14H17N5O |
Mr | 271.33 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 173 |
a, b, c (Å) | 5.3604 (8), 7.8585 (11), 16.357 (2) |
α, β, γ (°) | 87.4656 (17), 86.2519 (16), 85.6240 (17) |
V (Å3) | 685.04 (17) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.09 |
Crystal size (mm) | 1.02 × 0.35 × 0.03 |
Data collection | |
Diffractometer | Bruker APEXII CCD diffractometer |
Absorption correction | Multi-scan (SADABS; Bruker, 2008) |
Tmin, Tmax | 0.915, 0.997 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 6114, 3120, 2568 |
Rint | 0.013 |
(sin θ/λ)max (Å−1) | 0.651 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.036, 0.099, 1.04 |
No. of reflections | 3120 |
No. of parameters | 181 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.20, −0.22 |
Computer programs: APEX2 (Bruker, 2008), SAINT (Bruker, 2008), SHELXD (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).
D—H···A | D—H | H···A | D···A | D—H···A |
C3—H3···N2i | 0.95 | 2.52 | 3.4674 (15) | 177.0 |
C5—H5···N4ii | 0.95 | 2.46 | 3.3445 (15) | 154.2 |
Symmetry codes: (i) −x+1, −y, −z+1; (ii) −x−1, −y+1, −z+1. |
Acknowledgements
This work was supported by the Natural Science and Engineering Research Council of Canada and the Alberta Glycomics Centre.
References
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Fluorophores with properties responsive to their chemical environment, or which are reactive to the presence of specific functional groups, can be useful probes in chemistry and biology (Cairo et al., 2010; Lavis & Raines, 2008). We explored a series of analogs suitable for the Cu-catalyzed azide-alkyne cycloaddition (CuAAC) to identify substrates which were fluorogenic. Compounds with increased fluorescence upon conversion from either an azide or alkyne precursor to a triazole product would be of interest for detecting the presence of these functional groups in complex mixtures. The title compound, I, was found to be only weakly fluorescent, which is in contrast to the properties of the 4-azido-benzoxadiazole precursor, II. Thus, we designated compound I as a quenched fluorophore (Key & Cairo, 2011).
The benzoxadiazole and triazole rings of I are nearly eclipsed, as noted from the dihedral angle of 12.18 (5)° that was obtained from least-squares planes calculations. The hexyl side-chain adopted an essentially planar zigzag conformation [maximum deviation from the plane 0.0530 (8) Å]; the alkyl chain was twisted 20.89 (6)° with respect to the central triazole. There was an overall twist to the structure, with an angle of 32.86 (7)° between the benzoxadiazole group and the hexyl chain.
The packing of I in the solid state was stabilized by weak intermolecular C–H···N hydrogen bonds (H···N distances: 2.46-2.52 Å) and offset parallel stacking interactions (3.331-3.791 Å) of the triazole and benzoxadiazole rings (see Figures 3 and 4).