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

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3-Phenyl-1,5-di-2-pyridylpentane-1,5-dione

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aChemistry Department, Loughborough University, Loughborough, Leicestershire LE11 3TU, England, and bSchool of Chemistry, University of KwaZulu-Natal, Howard College, Durban 4041, South Africa
*Correspondence e-mail: v.mckee@lboro.ac.uk

(Received 15 November 2006; accepted 2 December 2006; online 8 December 2006)

The title compound, C21H18N2O2, shows both ππ stacking of the pyridine groups and significant C—H⋯O and C—H⋯N hydrogen bonding.

Comment

2,2′:6′,2′′-Terpyridine and its derivatives have been widely used for complexation of transition metals (Gao et al., 2003[Gao, J., Reibenspies, J. H. & Martell, A. E. (2003). J. Inorg. Biochem. 94, 272-278.]; Sharma et al., 2005[Sharma, S., Singh, S. K., Chandra, M. & Pandey, D. S. (2005). J. Inorg. Biochem. 99, 458-466.]). In more recent times there has been a lot of inter­est in these ligands as synthetic building blocks for supra­molecular structures (Hofmeier & Schubert, 2004[Hofmeier, H. & Schubert, U. S. (2004). Chem. Soc. Rev. 33, 273-399.]). Multistep syntheses (Kröhnke, 1976[Kröhnke, K. (1976). Synthesis, pp. 1-24.]; Collin et al., 1996[Collin, J.-P., Harriman, A., Heitz, V., Odobel, F. & Sauvage, J.-P. (1996). Coord. Chem. Rev. 148, 63-69.]), as well as single-step approaches for these ligands, have been developed (Tu et al., 2005[Tu, S., Li, T., Shi, F., Wang, Q., Zhang, J., Xu, J., Zhu, X., Zhang, X., Zhu, S. & Shi, D. (2005). Synthesis, 18, 3045-3050.]).

The title compound, (I)[link], is a synthetic inter­mediate for the compound 4′-phenyl-2,2′:6′,2′′-terpyridine. The synthesis and characterization of the latter have been described previously along with other derivatives (Constable et al., 1990[Constable, E. C., Lewis, J., Liptrot, M. C. & Raithby, P. R. (1990). Inorg. Chim. Acta, 178, 47-54.]; Moya et al., 2001[Moya, S. A., Pastene, R., Le Bozec, H., Baricelli, P. J., Pardey, A. J. & Gimeno, J. (2001). Inorg. Chim. Acta, 312, 7-14.]). The structure of the fluorinated analogue, 3-(4-fluoro­phen­yl)­pentane-1,5-bis­(2-pyrid­yl)-1,5-dione, (II), has been reported previously (Constable et al., 1998[Constable, E. C., Neuberger, M., Smith, D. R. & Zehnder, M. (1998). Inorg. Chim. Acta, 275, 359-365.]). A search of the CSD (Version 5.27) showed that no other members of this family have been structurally characterized (Allen, 2002[Allen, F. H. (2002). Acta Cryst. B58, 380-388.]; Fletcher et al., 1996[Fletcher, D. A., McMeeking, R. F. & Parkin, D. (1996). J. Chem. Inf. Comput. Sci. 36, 746-749.]).

[Scheme 1]

The structure of (I)[link] is shown in Fig. 1[link]. The mean planes of the two pyridine rings are inclined at 11.26 (7)°. The phenyl ring, comprising C16–C21, is inclined by 87.08 (3)° to the mean plane of the rest of the mol­ecule. The fluorinated analogue (II) is essentially isomorphous with the present compound, the fluorinated phenyl group making no significant difference to the mol­ecular packing. Constable et al. (1998[Constable, E. C., Neuberger, M., Smith, D. R. & Zehnder, M. (1998). Inorg. Chim. Acta, 275, 359-365.]) stated that there were neither stacking inter­actions nor significant short inter­molecular contacts in the crystal structure of (II). We have perhaps taken a more liberal view, and observed both ππ stacking and C—H⋯O/N hydrogen bonding in (I)[link].

Fig. 2[link] shows a packing diagram, viewed perpendicular to the a axis and illustrates the ππ stacking of the pyridine rings, in which rings comprising N1/C1–C5 alternate with those comprising N2/C11–C15. As mentioned above, the rings are inclined at 11.26 (7)°; the centroid–centroid distance is 3.907 Å and the centroid of the N1/C1–C5 ring is 3.684 (1) Å from the mean plane of the N2/C11–C15 ring under symmetry operation (−1 + x, y, −1 + z).

Three sets of inter­molecular hydrogen-bonding inter­actions are shown in Fig. 3[link] and listed in Table 1[link]. Each of the inter­actions is paired by symmetry, giving rise to cyclic patterns which can be described as R22 (16), R22 (10) and R22(6) for C18—H18⋯O2i, C4—H4⋯O1ii and C1—H1⋯N1iii, respectively (Etter et al., 1990[Etter, M. C., MacDonald, J. C. & Bernstein, J. (1990). Acta Cryst. B46, 256-262.]). The D⋯A distances and D—H⋯A angles in these inter­actions are within the ranges generally observed for such weak hydrogen bonds (Desiraju & Steiner, 1999[Desiraju, G. & Steiner, T. (1999). The Weak Hydrogen Bond in Structural Chemistry and Biology. Oxford University Press.]) and, collectively, they are likely to be responsible for the observed packing.

[Figure 1]
Figure 1
The molecular structure of (I)[link]; displacement ellipsoids are drawn at the 50% probability level.
[Figure 2]
Figure 2
Packing diagram viewed down the a axis and showing ππ stacking. H atoms have been omitted for clarity.
[Figure 3]
Figure 3
Inter­molecular C—H⋯O and C—H⋯N hydrogen bonding (dashed lines). H atoms not involved in hydrogen bonding have been omitted for clarity. Symmetry codes as in Table 1[link].

Experimental

Compound (I) was synthesized as previously reported (Cave & Raston, 2001[Cave, G. W. V. & Raston, C. L. (2001). J. Chem. Soc. Perkin Trans. 1, pp. 3258-3264.]). The product was recrystallized at room temperature from a methanol–chloro­form (1:1) mixture, yielding colourless crystals (m.p. 422–424 K).

Crystal data
  • C21H18N2O2

  • Mr = 330.37

  • Triclinic, [P \overline 1]

  • a = 8.3545 (5) Å

  • b = 10.3696 (7) Å

  • c = 10.6370 (7) Å

  • α = 95.208 (1)°

  • β = 110.924 (1)°

  • γ = 99.762 (1)°

  • V = 836.74 (9) Å3

  • Z = 2

  • Dx = 1.311 Mg m−3

  • Mo Kα radiation

  • μ = 0.09 mm−1

  • T = 150 (2) K

  • Block, colourless

  • 0.45 × 0.42 × 0.17 mm

Data collection
  • Bruker SMART APEX-II CCD diffractometer

  • ω scans

  • Absorption correction: multi-scan (SADABS; Sheldrick, 2003[Sheldrick, G. M. (2003). SADABS. Version 2.10. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.963, Tmax = 0.986

  • 8223 measured reflections

  • 3832 independent reflections

  • 3149 reflections with I > 2σ(I)

  • Rint = 0.019

  • θmax = 27.5°

Refinement
  • Refinement on F2

  • R[F2 > 2σ(F2)] = 0.042

  • wR(F2) = 0.111

  • S = 1.09

  • 3832 reflections

  • 226 parameters

  • H-atom parameters constrained

  • w = 1/[σ2(Fo2) + (0.0518P)2 + 0.1695P] where P = (Fo2 + 2Fc2)/3

  • (Δ/σ)max < 0.001

  • Δρmax = 0.26 e Å−3

  • Δρmin = −0.24 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
C18—H18⋯O2i 0.95 2.62 3.4913 (15) 153
C4—H4⋯O1ii 0.95 2.42 3.2556 (16) 146
C1—H1⋯N1iii 0.95 2.64 3.4588 (18) 145
Symmetry codes: (i) -x+1, -y+1, -z; (ii) -x, -y+1, -z-1; (iii) -x-1, -y, -z-1.

H atoms bonded to C and N were inserted at calculated positions and refined using a riding model. The constrained distances were 0.95, 0.99 and 1.00 Å for aryl, methyl­ene and tertiary H atoms, respectively. They were assigned Uiso(H) = 1.2Ueq(carrier atom).

Data collection: APEX2 (Bruker, 2005[Bruker (2005). APEX2 (Version 2.1) and SAINT (Version 7.23A). Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2005[Bruker (2005). APEX2 (Version 2.1) and SAINT (Version 7.23A). Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997[Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997[Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany.]); molecular graphics: SHELXTL (Sheldrick, 2001[Sheldrick, G. M. (2001). SHELXTL. Version 6.12. Bruker AXS Inc., Madison, Wisconsin, USA.]); software used to prepare material for publication: SHELXTL.

Supporting information


Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Sheldrick, 2001); software used to prepare material for publication: SHELXTL.

3-Phenyl-1,5-di-2-pyridylpentane-1,5-dione top
Crystal data top
C21H18N2O2Z = 2
Mr = 330.37F(000) = 348
Triclinic, P1Dx = 1.311 Mg m3
a = 8.3545 (5) ÅMo Kα radiation, λ = 0.71073 Å
b = 10.3696 (7) ÅCell parameters from 3056 reflections
c = 10.6370 (7) Åθ = 2.7–31.5°
α = 95.208 (1)°µ = 0.09 mm1
β = 110.924 (1)°T = 150 K
γ = 99.762 (1)°Block, colourless
V = 836.74 (9) Å30.45 × 0.42 × 0.17 mm
Data collection top
Bruker SMART APEX-II CCD
diffractometer
3832 independent reflections
Radiation source: fine-focus sealed tube3149 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.019
ω scansθmax = 27.5°, θmin = 2.0°
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)
h = 1010
Tmin = 0.963, Tmax = 0.986k = 1313
8223 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)] = 0.042Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.111H-atom parameters constrained
S = 1.09 w = 1/[σ2(Fo2) + (0.0518P)2 + 0.1695P]
where P = (Fo2 + 2Fc2)/3
3832 reflections(Δ/σ)max < 0.001
226 parametersΔρmax = 0.26 e Å3
0 restraintsΔρmin = 0.24 e Å3
Special details top

Experimental. 1H NMR (300 MHz, CDCl3): δ 8.60 (d, J = 4.9 Hz, 2H), 7.92 (d, J = 5.8 Hz, 2H), 7.75 (t, J = 7.6 Hz, 2H), 7.42–7.34 (m, 4H), 7.24–7.19 (m, 2H), 7.13–7.08 (m, 1H), 4.14 (quint, J = 7.1 Hz, 1H) 3.68 (qd, 4H). 13C NMR (75 MHz, CDCl3): δ C 199.93, 153.28, 148.74, 144.54, 136.94, 128.37, 127.73, 127.08, 126.33, 121.86, 44.18, 36.11.

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*/Ueq
N10.35196 (14)0.16135 (11)0.49191 (11)0.0282 (2)
C10.47378 (18)0.11329 (14)0.61683 (14)0.0342 (3)
H10.55670.03360.62890.041*
C20.48469 (19)0.17425 (14)0.72960 (13)0.0344 (3)
H20.57520.13800.81600.041*
C30.3633 (2)0.28745 (15)0.71475 (13)0.0360 (3)
H30.36780.33030.79080.043*
C40.23359 (18)0.33848 (14)0.58688 (13)0.0309 (3)
H40.14650.41590.57350.037*
C50.23508 (16)0.27262 (12)0.47864 (12)0.0228 (3)
C60.10237 (15)0.32889 (12)0.33738 (12)0.0226 (3)
O10.01339 (12)0.42531 (9)0.31951 (9)0.0324 (2)
C70.12369 (15)0.26619 (12)0.21971 (11)0.0214 (2)
H7A0.14410.16860.24270.026*
H7B0.22780.28740.20550.026*
C80.03857 (15)0.31553 (11)0.08751 (11)0.0196 (2)
H80.07240.41420.07770.024*
C90.00051 (15)0.28325 (12)0.03820 (11)0.0223 (3)
H9A0.11030.30880.03320.027*
H9B0.01550.18640.03800.027*
C100.14735 (15)0.35513 (12)0.17000 (12)0.0216 (2)
O20.24581 (12)0.45740 (9)0.17391 (9)0.0301 (2)
C110.16752 (16)0.29902 (12)0.29879 (12)0.0226 (3)
C120.28339 (17)0.37379 (13)0.42286 (13)0.0287 (3)
H120.34740.46000.42670.034*
C130.30403 (19)0.32054 (15)0.54078 (13)0.0353 (3)
H130.38210.36940.62720.042*
C140.2090 (2)0.19514 (15)0.53014 (14)0.0393 (4)
H140.22020.15560.60910.047*
C150.0971 (2)0.12797 (15)0.40237 (15)0.0426 (4)
H150.03260.04130.39620.051*
N20.07389 (16)0.17725 (11)0.28674 (11)0.0326 (3)
C160.19229 (15)0.25953 (11)0.09513 (11)0.0193 (2)
C170.34421 (15)0.34252 (12)0.09007 (11)0.0220 (2)
H170.35240.43560.08100.026*
C180.48440 (16)0.29177 (13)0.09804 (12)0.0253 (3)
H180.58760.35010.09380.030*
C190.47380 (17)0.15584 (13)0.11217 (12)0.0275 (3)
H190.56950.12080.11760.033*
C200.32209 (17)0.07150 (12)0.11837 (12)0.0269 (3)
H200.31370.02170.12840.032*
C210.18303 (16)0.12285 (12)0.10991 (12)0.0233 (3)
H210.07990.06430.11420.028*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0292 (6)0.0286 (6)0.0224 (5)0.0024 (4)0.0063 (4)0.0035 (4)
C10.0339 (7)0.0326 (7)0.0274 (7)0.0020 (6)0.0049 (6)0.0002 (5)
C20.0368 (7)0.0393 (8)0.0202 (6)0.0131 (6)0.0020 (5)0.0015 (5)
C30.0480 (8)0.0416 (8)0.0197 (6)0.0156 (7)0.0106 (6)0.0096 (6)
C40.0360 (7)0.0341 (7)0.0230 (6)0.0061 (6)0.0111 (6)0.0090 (5)
C50.0233 (6)0.0262 (6)0.0197 (6)0.0071 (5)0.0078 (5)0.0058 (5)
C60.0211 (6)0.0265 (6)0.0207 (6)0.0057 (5)0.0076 (5)0.0076 (5)
O10.0285 (5)0.0361 (5)0.0265 (5)0.0038 (4)0.0067 (4)0.0115 (4)
C70.0193 (6)0.0258 (6)0.0172 (5)0.0026 (5)0.0052 (4)0.0059 (4)
C80.0197 (5)0.0208 (5)0.0168 (5)0.0021 (4)0.0062 (4)0.0039 (4)
C90.0207 (6)0.0269 (6)0.0176 (5)0.0017 (5)0.0069 (5)0.0041 (4)
C100.0231 (6)0.0228 (6)0.0196 (6)0.0047 (5)0.0095 (5)0.0016 (4)
O20.0347 (5)0.0256 (5)0.0250 (5)0.0034 (4)0.0102 (4)0.0029 (4)
C110.0232 (6)0.0256 (6)0.0187 (6)0.0044 (5)0.0081 (5)0.0029 (5)
C120.0318 (7)0.0268 (6)0.0218 (6)0.0019 (5)0.0061 (5)0.0010 (5)
C130.0398 (8)0.0400 (8)0.0187 (6)0.0045 (6)0.0049 (6)0.0021 (5)
C140.0467 (9)0.0461 (9)0.0225 (7)0.0042 (7)0.0111 (6)0.0133 (6)
C150.0522 (9)0.0380 (8)0.0290 (7)0.0087 (7)0.0121 (7)0.0111 (6)
N20.0369 (6)0.0310 (6)0.0230 (5)0.0049 (5)0.0084 (5)0.0057 (4)
C160.0205 (5)0.0227 (6)0.0119 (5)0.0030 (4)0.0037 (4)0.0032 (4)
C170.0223 (6)0.0214 (6)0.0185 (5)0.0020 (5)0.0050 (5)0.0021 (4)
C180.0202 (6)0.0314 (7)0.0219 (6)0.0018 (5)0.0068 (5)0.0036 (5)
C190.0258 (6)0.0346 (7)0.0236 (6)0.0121 (5)0.0084 (5)0.0054 (5)
C200.0344 (7)0.0233 (6)0.0236 (6)0.0090 (5)0.0099 (5)0.0054 (5)
C210.0252 (6)0.0233 (6)0.0190 (6)0.0020 (5)0.0066 (5)0.0049 (4)
Geometric parameters (Å, º) top
N1—C11.3385 (17)C10—C111.5023 (16)
N1—C51.3396 (16)C11—N21.3367 (16)
C1—C21.3878 (19)C11—C121.3882 (17)
C1—H10.9500C12—C131.3826 (18)
C2—C31.371 (2)C12—H120.9500
C2—H20.9500C13—C141.376 (2)
C3—C41.3879 (19)C13—H130.9500
C3—H30.9500C14—C151.381 (2)
C4—C51.3936 (17)C14—H140.9500
C4—H40.9500C15—N21.3375 (17)
C5—C61.5030 (16)C15—H150.9500
C6—O11.2154 (14)C16—C171.3881 (16)
C6—C71.5129 (16)C16—C211.3975 (16)
C7—C81.5327 (15)C17—C181.3884 (17)
C7—H7A0.9900C17—H170.9500
C7—H7B0.9900C18—C191.3881 (18)
C8—C161.5204 (16)C18—H180.9500
C8—C91.5330 (15)C19—C201.3891 (18)
C8—H81.0000C19—H190.9500
C9—C101.5158 (16)C20—C211.3846 (17)
C9—H9A0.9900C20—H200.9500
C9—H9B0.9900C21—H210.9500
C10—O21.2144 (14)
C1—N1—C5117.02 (11)O2—C10—C11119.74 (10)
N1—C1—C2123.15 (13)O2—C10—C9121.64 (10)
N1—C1—H1118.4C11—C10—C9118.61 (10)
C2—C1—H1118.4N2—C11—C12123.42 (11)
C3—C2—C1119.19 (12)N2—C11—C10117.49 (10)
C3—C2—H2120.4C12—C11—C10119.08 (11)
C1—C2—H2120.4C13—C12—C11118.81 (12)
C2—C3—C4118.98 (12)C13—C12—H12120.6
C2—C3—H3120.5C11—C12—H12120.6
C4—C3—H3120.5C14—C13—C12118.51 (12)
C3—C4—C5117.98 (13)C14—C13—H13120.7
C3—C4—H4121.0C12—C13—H13120.7
C5—C4—H4121.0C13—C14—C15118.67 (13)
N1—C5—C4123.66 (11)C13—C14—H14120.7
N1—C5—C6116.86 (10)C15—C14—H14120.7
C4—C5—C6119.47 (11)N2—C15—C14124.11 (13)
O1—C6—C5120.13 (10)N2—C15—H15117.9
O1—C6—C7121.84 (11)C14—C15—H15117.9
C5—C6—C7117.96 (10)C11—N2—C15116.48 (11)
C6—C7—C8111.75 (9)C17—C16—C21118.25 (11)
C6—C7—H7A109.3C17—C16—C8120.93 (10)
C8—C7—H7A109.3C21—C16—C8120.82 (10)
C6—C7—H7B109.3C16—C17—C18121.14 (11)
C8—C7—H7B109.3C16—C17—H17119.4
H7A—C7—H7B107.9C18—C17—H17119.4
C16—C8—C7110.71 (9)C19—C18—C17120.04 (11)
C16—C8—C9111.00 (9)C19—C18—H18120.0
C7—C8—C9111.88 (9)C17—C18—H18120.0
C16—C8—H8107.7C18—C19—C20119.46 (12)
C7—C8—H8107.7C18—C19—H19120.3
C9—C8—H8107.7C20—C19—H19120.3
C10—C9—C8112.00 (9)C21—C20—C19120.18 (11)
C10—C9—H9A109.2C21—C20—H20119.9
C8—C9—H9A109.2C19—C20—H20119.9
C10—C9—H9B109.2C20—C21—C16120.93 (11)
C8—C9—H9B109.2C20—C21—H21119.5
H9A—C9—H9B107.9C16—C21—H21119.5
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C18—H18···O2i0.952.623.4913 (15)153
C4—H4···O1ii0.952.423.2556 (16)146
C1—H1···N1iii0.952.643.4588 (18)145
Symmetry codes: (i) x+1, y+1, z; (ii) x, y+1, z1; (iii) x1, y, z1.
 

Acknowledgements

We acknowledge the use of the EPSRC's Chemical Database Service at Daresbury.

References

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