organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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ISSN: 2056-9890

2,4,5-Tris(pyridin-4-yl)-4,5-di­hydro-1,3-oxazole

aFacultad de Ingeniería Mochis, Universidad Autónoma de Sinaloa, Fuente de Poseidón y Prol. Ángel Flores, 81223 Los Mochis, Sinaloa, Mexico, bCentro de Investigaciones Químicas, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, 62209 Cuernavaca, Morelos, Mexico, and cCentro de Graduados e Investigación del Instituto Tecnológico de Tijuana, Apdo. Postal 1166, 22500 Tijuana, BC, Mexico
*Correspondence e-mail: gaxiolajose@yahoo.com.mx

(Received 26 March 2012; accepted 17 May 2012; online 26 May 2012)

In the title compound, C18H14N4O, the mol­ecules are disordered about a crystallographic twofold axis, leading to 50:50 disorder of the O- and N-atom sites within the oxazole ring. As a consequence, symmetry-related oxazole C—N and C—O bonds are averaged. The oxazole ring makes a dihedral angle of 6.920 (1)° with the pyridyl ring in the 2-position and 60.960 (2)° with the pyridyl rings in the 4- and 5-positions.

Related literature

For background to the synthesis of oxazoles see: Graham (2010[Graham, T. H. (2010). Org. Lett. 12, 3614-3617.]); Aspinall et al. (2011[Aspinall, H. C., Beckingham, O., Farrar, M. D., Greeves, N. & Thomas, C. D. (2011). Tetrahedron Lett. 52, 5120-5123.]). For the use of pyridyl­oxazole ligands in the construction of metal-organic complexes see: Bettencourt-Dias et al. (2010[Bettencourt-Dias, A., Barber, P. S., Viswanathan, S., Lill, D. T., Rollett, A., Ling, G. & Altun, S. (2010). Inorg. Chem. 49, 8848-8861.], 2012[Bettencourt-Dias, A., Barber, P. S. & Bauer, S. (2012). J. Am. Chem. Soc. 134, 6987-6994.]). For the use of tripyridyl ligands in the construction of metal-organic coordination complexes and polymers, see: Campos-Gaxiola et al. (2007[Campos-Gaxiola, J. J., Höpfl, H. & Parra-Hake, M. (2007). J. Mex. Chem. Soc. 51, 27-32.], 2008[Campos-Gaxiola, J. J., Höpfl, H. & Parra-Hake, M. (2008). Inorg. Chim. Acta, 361, 248-254.], 2010[Campos-Gaxiola, J. J., Höpfl, H. & Parra-Hake, M. (2010). Inorg. Chim. Acta, 363, 1179-1185.]); Liang et al. (2008[Liang, X.-Q., Xiao, H.-P., Liu, B.-L., Li, Y.-Z., Zuo, J.-L. & You, X.-Z. (2008). Polyhedron, 27, 2494-2500.], 2009[Liang, X.-Q., Zhou, X.-H., Chen, C., Xiao, H.-P., Li, Y.-Z., Zuo, J.-L. & You, X.-Z. (2009). Cryst. Growth Des. 9, 1041-1053.]); Yang et al. (2010[Yang, F. L., Li, B., Hanajima, T., Einaga, Y., Huang, R. B., Zheng, L. S. & Tao, J. (2010). Dalton Trans. 39, 2288-2292.]); Chen et al. (2011[Chen, H., Xiao, D., Fan, L., He, J., Yan, S., Zhang, G., Sun, D., Ye, Z., Yuan, R. & Wang, E. (2011). CrystEngComm, 13, 7098-7107.]).

[Scheme 1]

Experimental

Crystal data
  • C18H14N4O

  • Mr = 302.33

  • Orthorhombic, P b c n

  • a = 15.9777 (13) Å

  • b = 11.4504 (9) Å

  • c = 7.7573 (6) Å

  • V = 1419.21 (19) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.09 mm−1

  • T = 293 K

  • 0.43 × 0.38 × 0.34 mm

Data collection
  • Bruker SMART CCD area-detector diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2001[Bruker (2001). SAINT-Plus and SADABS Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.962, Tmax = 0.969

  • 12571 measured reflections

  • 1254 independent reflections

  • 1107 reflections with I > 2σ(I)

  • Rint = 0.030

Refinement
  • R[F2 > 2σ(F2)] = 0.039

  • wR(F2) = 0.107

  • S = 1.07

  • 1254 reflections

  • 106 parameters

  • H-atom parameters constrained

  • Δρmax = 0.16 e Å−3

  • Δρmin = −0.23 e Å−3

Data collection: SMART (Bruker, 2000[Bruker (2000). SMART. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT-Plus (Bruker, 2001[Bruker (2001). SAINT-Plus and SADABS Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); software used to prepare material for publication: SHELXTL.

Supporting information


Comment top

Several pyridyloxazole derivatives (Bettencourt-Dias et al., 2010 and 2012) have provided effective highly luminescent Ln(III) complexes. Moreover, the coordination chemistry of transition metals with polypyridyl ligands has progressed considerably during the last decade, and has been widely used for the construction of coordination polymers with luminescent properties (Liang et al., 2008, 2009; Chen et al., 2011).

In the course of our studies on transition metal complexes with tripyridyl ligands (Campos-Gaxiola et al., 2008, 2010), we have synthesized the title compound (I) and report its crystal structure here (Fig. 1).

As part of our ongoing research on the design and synthesis of new metal complexes with fluorescent properties, we are interested in using the title compound as a ligand for the synthesis of transition and rare earth metal complexes.

In (I), the molecules are disordered about crystallographic 2-fold-axes, therefore, the C1—N1/C1—O1 and C2—N1/C2—O1 distances are average values. The pyridyl rings attached at positions 4 and 5 show trans configuration. The torsion angles for the fragments C(2)i—C(2)—C(6)—C(7) and C(2)i—C(2)—C(6)—C(10) (symmetry code: (i) -x + 1,y,-z + 1/2) are 104.78 (14)° and -74.55 (15)°, respectively. The oxazole ring forms dihedral angles of 6.920 (2)° with the pyridyl ring in position 2, and 60.960 (1)° with pyridyl rings in positions 4 and 5. No classical hydrogen bonds are observed in the crystal structure.

Related literature top

For background to the synthesis of oxazoles see: Graham (2010); Aspinall et al. (2011). For the use of pyridyloxazole ligands in the construction of metal-organic complexes see: Bettencourt-Dias et al. (2010, 2012). For the use of tripyridyl ligands in the construction of metal-organic coordination complexes and polymers, see: Campos-Gaxiola et al. (2007, 2008, 2010); Liang et al. (2008, 2009); Yang et al. (2010); Chen et al. (2011).

Experimental top

The synthesis of the title compound included reagent grade starting materials and solvents. A mixture of pyridine-4-carboxaldehyde (5 ml, 0.0531 mol) and ammonium hydroxide (15 ml, 0.3843 mol), dissolved in THF (100 ml) was stirred at 50 °C for 72 h and the solvent removed under reduced pressure. The remaining solid was re-crystallized in methanol, providing colorless crystals. Yield (3.5 g, 60%). IR (KBr): 3154, 3035, 3005, 2889, 1660, 1596, 1557, 1486, 1492, 1412, 1333, 1290, 1077, 992, 823, 677 cm-1.

Refinement top

All H atoms on C atoms were positioned geometrically and refined as riding atoms, with (C—H = 0.93 Å) and Uiso(H) = 1.2 Ueq(C). The molecules are disordered over crystallographic 2-fold axes, therefore, the C1—N1/C1—O1 and C2—N1/C2—O1 distances are average values. The EXYZ and EADP constraint instructions in SHELXL-97 were used for atoms N1 and O1 in order to model the disorder properly during the refinement.

Computing details top

Data collection: SMART (Bruker, 2000); cell refinement: SAINT-Plus (Bruker, 2001); data reduction: SAINT-Plus (Bruker, 2001); program(s) used to solve structure: SHELXS97 (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).

Figures top
[Figure 1] Fig. 1. The molecular structure of (I) showing displacement ellipsoids at the 50% probability level. The molecule sits on a crystallographic 2-fold axis (symmetry operation: -x + 1,y,-z + 1/2]), which forces the oxazole ring to be disordered, so that the atoms labelled O1 and N1 occupy sites that are 50% oxygen and 50% nitrogen. These are labelled separately in the diagram to emphasize the chemical nature of the molecules.
2,4,5-Tris(pyridin-4-yl)-4,5-dihydro-1,3-oxazole top
Crystal data top
C18H14N4OF(000) = 632
Mr = 302.33Dx = 1.415 Mg m3
Orthorhombic, PbcnMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2n 2abCell parameters from 5620 reflections
a = 15.9777 (13) Åθ = 2.2–28.3°
b = 11.4504 (9) ŵ = 0.09 mm1
c = 7.7573 (6) ÅT = 293 K
V = 1419.21 (19) Å3Rectangular prism, colorless
Z = 40.43 × 0.38 × 0.34 mm
Data collection top
Bruker SMART CCD area-detector
diffractometer
1254 independent reflections
Radiation source: fine-focus sealed tube1107 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.030
ϕ and ω scansθmax = 25.0°, θmin = 2.2°
Absorption correction: multi-scan
(SADABS; Bruker, 2001)
h = 1919
Tmin = 0.962, Tmax = 0.969k = 1313
12571 measured reflectionsl = 99
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)] = 0.039Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.107H-atom parameters constrained
S = 1.07 w = 1/[σ2(Fo2) + (0.0526P)2 + 0.3873P]
where P = (Fo2 + 2Fc2)/3
1254 reflections(Δ/σ)max < 0.001
106 parametersΔρmax = 0.16 e Å3
0 restraintsΔρmin = 0.23 e Å3
Crystal data top
C18H14N4OV = 1419.21 (19) Å3
Mr = 302.33Z = 4
Orthorhombic, PbcnMo Kα radiation
a = 15.9777 (13) ŵ = 0.09 mm1
b = 11.4504 (9) ÅT = 293 K
c = 7.7573 (6) Å0.43 × 0.38 × 0.34 mm
Data collection top
Bruker SMART CCD area-detector
diffractometer
1254 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2001)
1107 reflections with I > 2σ(I)
Tmin = 0.962, Tmax = 0.969Rint = 0.030
12571 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0390 restraints
wR(F2) = 0.107H-atom parameters constrained
S = 1.07Δρmax = 0.16 e Å3
1254 reflectionsΔρmin = 0.23 e Å3
106 parameters
Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
C10.50000.86189 (17)0.25000.0382 (5)
N10.44050 (7)0.80349 (9)0.17275 (14)0.0380 (3)0.50
O10.44050 (7)0.80349 (9)0.17275 (14)0.0380 (3)0.50
C20.45914 (8)0.68010 (11)0.19468 (17)0.0327 (3)
H20.47130.64580.08170.039*
N20.50001.23405 (16)0.25000.0507 (5)
N30.25339 (8)0.49131 (13)0.42490 (18)0.0509 (4)
C30.50000.99035 (17)0.25000.0327 (4)
C40.43313 (9)1.05212 (13)0.18356 (19)0.0405 (4)
H40.38701.01360.13740.049*
C50.43658 (11)1.17225 (14)0.1875 (2)0.0480 (4)
H50.39111.21310.14310.058*
C60.38645 (8)0.61604 (12)0.27474 (18)0.0334 (3)
C70.31909 (9)0.67265 (13)0.34906 (19)0.0406 (4)
H70.31680.75380.35080.049*
C80.25525 (9)0.60737 (15)0.4207 (2)0.0487 (4)
H80.21050.64740.46940.058*
C90.31870 (10)0.43864 (13)0.3541 (2)0.0500 (4)
H90.31970.35740.35600.060*
C100.38510 (9)0.49502 (13)0.2781 (2)0.0423 (4)
H100.42870.45240.22950.051*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0407 (12)0.0313 (10)0.0426 (11)0.0000.0142 (9)0.000
N10.0352 (6)0.0292 (6)0.0495 (7)0.0013 (4)0.0024 (5)0.0045 (5)
O10.0352 (6)0.0292 (6)0.0495 (7)0.0013 (4)0.0024 (5)0.0045 (5)
C20.0306 (7)0.0276 (7)0.0399 (7)0.0015 (6)0.0005 (6)0.0017 (6)
N20.0645 (13)0.0313 (9)0.0562 (12)0.0000.0062 (10)0.000
N30.0354 (7)0.0536 (8)0.0637 (9)0.0076 (6)0.0014 (6)0.0109 (7)
C30.0340 (10)0.0289 (10)0.0352 (10)0.0000.0077 (8)0.000
C40.0365 (8)0.0394 (8)0.0456 (9)0.0001 (6)0.0006 (6)0.0014 (7)
C50.0526 (9)0.0391 (8)0.0523 (9)0.0118 (7)0.0019 (7)0.0053 (7)
C60.0289 (7)0.0326 (7)0.0387 (7)0.0005 (6)0.0048 (6)0.0003 (6)
C70.0322 (8)0.0360 (8)0.0536 (9)0.0030 (6)0.0006 (7)0.0008 (7)
C80.0296 (8)0.0565 (10)0.0602 (10)0.0049 (7)0.0043 (7)0.0032 (8)
C90.0430 (9)0.0354 (8)0.0717 (11)0.0077 (7)0.0053 (8)0.0049 (7)
C100.0342 (7)0.0329 (7)0.0598 (9)0.0008 (6)0.0004 (7)0.0039 (7)
Geometric parameters (Å, º) top
C1—N11.3077 (14)C3—C4i1.3811 (18)
C1—O1i1.3077 (14)C4—C51.377 (2)
C1—C31.471 (3)C4—H40.9300
N1—C21.4539 (17)C5—H50.9300
C2—C61.5076 (19)C6—C71.382 (2)
C2—C2i1.563 (3)C6—C101.386 (2)
C2—H20.9800C7—C81.381 (2)
N2—C51.3277 (19)C7—H70.9300
N2—C5i1.3277 (19)C8—H80.9300
N3—C91.324 (2)C9—C101.375 (2)
N3—C81.330 (2)C9—H90.9300
C3—C41.3811 (18)C10—H100.9300
N1—C1—O1i118.50 (17)N2—C5—C4124.82 (15)
N1—C1—C3120.75 (9)N2—C5—H5117.6
O1i—C1—C3120.75 (9)C4—C5—H5117.6
N1i—C1—C3120.75 (9)C7—C6—C10116.67 (13)
C1—N1—C2107.12 (12)C7—C6—C2122.92 (12)
N1—C2—C6111.30 (11)C10—C6—C2120.41 (12)
N1—C2—C2i103.62 (7)C8—C7—C6119.27 (14)
C6—C2—C2i114.67 (12)C8—C7—H7120.4
N1—C2—H2109.0C6—C7—H7120.4
C6—C2—H2109.0N3—C8—C7124.56 (15)
C2i—C2—H2109.0N3—C8—H8117.7
C5—N2—C5i115.59 (19)C7—C8—H8117.7
C9—N3—C8115.29 (13)N3—C9—C10124.89 (14)
C4—C3—C4i118.38 (19)N3—C9—H9117.6
C4—C3—C1120.81 (9)C10—C9—H9117.6
C4i—C3—C1120.81 (9)C9—C10—C6119.31 (14)
C5—C4—C3118.19 (15)C9—C10—H10120.3
C5—C4—H4120.9C6—C10—H10120.3
C3—C4—H4120.9
O1i—C1—N1—C20.62 (6)C3—C4—C5—N20.4 (2)
N1i—C1—N1—C20.62 (6)N1—C2—C6—C712.42 (18)
C3—C1—N1—C2179.38 (6)C2i—C2—C6—C7104.78 (14)
C1—N1—C2—C6125.19 (10)N1—C2—C6—C10168.25 (12)
C1—N1—C2—C2i1.45 (15)C2i—C2—C6—C1074.55 (15)
N1—C1—C3—C46.47 (9)C10—C6—C7—C80.2 (2)
O1i—C1—C3—C4173.53 (9)C2—C6—C7—C8179.56 (13)
N1i—C1—C3—C4173.53 (9)C9—N3—C8—C70.1 (2)
N1—C1—C3—C4i173.53 (9)C6—C7—C8—N30.3 (2)
O1i—C1—C3—C4i6.47 (9)C8—N3—C9—C100.7 (3)
N1i—C1—C3—C4i6.47 (9)N3—C9—C10—C60.8 (3)
C4i—C3—C4—C50.17 (10)C7—C6—C10—C90.3 (2)
C1—C3—C4—C5179.83 (10)C2—C6—C10—C9179.05 (14)
C5i—N2—C5—C40.19 (11)
Symmetry code: (i) x+1, y, z+1/2.

Experimental details

Crystal data
Chemical formulaC18H14N4O
Mr302.33
Crystal system, space groupOrthorhombic, Pbcn
Temperature (K)293
a, b, c (Å)15.9777 (13), 11.4504 (9), 7.7573 (6)
V3)1419.21 (19)
Z4
Radiation typeMo Kα
µ (mm1)0.09
Crystal size (mm)0.43 × 0.38 × 0.34
Data collection
DiffractometerBruker SMART CCD area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Bruker, 2001)
Tmin, Tmax0.962, 0.969
No. of measured, independent and
observed [I > 2σ(I)] reflections
12571, 1254, 1107
Rint0.030
(sin θ/λ)max1)0.595
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.039, 0.107, 1.07
No. of reflections1254
No. of parameters106
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.16, 0.23

Computer programs: SMART (Bruker, 2000), SAINT-Plus (Bruker, 2001), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

 

Acknowledgements

This work was supported by the Secretaría de Educación Pública (PROMEP, UAS-PTC-033) and the Universidad Autónoma de Sinaloa (DGIP, PROFAPI2011/033).

References

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First citationLiang, X.-Q., Xiao, H.-P., Liu, B.-L., Li, Y.-Z., Zuo, J.-L. & You, X.-Z. (2008). Polyhedron, 27, 2494–2500.  Web of Science CSD CrossRef CAS Google Scholar
First citationLiang, X.-Q., Zhou, X.-H., Chen, C., Xiao, H.-P., Li, Y.-Z., Zuo, J.-L. & You, X.-Z. (2009). Cryst. Growth Des. 9, 1041–1053.  Web of Science CSD CrossRef CAS Google Scholar
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