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Acta Crystallogr Sect E Struct Rep Online. 2008 January 1; 64(Pt 1): o28–o29.
Published online 2007 December 6. doi:  10.1107/S1600536807060254
PMCID: PMC2914989

2,6-Bis[1-(2-isopropyl­phenyl­imino)­ethyl]­pyridine

Abstract

The title compound, C27H31N3, has E substitution at each imine double bond where the two N atoms adopt a transtrans relationship. The benzene rings are twisted out of the mean plane of the pyridine ring; the mean planes of the aromatic groups are rotated by 63.0 (1) and 72.58 (8)°. The crystal structure is sustained mainly by C—H(...)π and hydro­phobic methyl–methyl inter­actions.

Related literature

For related literature, see: Alyea & Merrel (1974 [triangle]); Bernstein et al. (1995 [triangle]); Bianchini & Hon Man (2000 [triangle]); Britovsek et al. (1999 [triangle]); Huang et al. (2006 [triangle]); Mentes et al. (2001 [triangle]); Orrell et al. (1997 [triangle]); Small & Brookhart (1998 [triangle]); Togni & Venanzi (1994 [triangle]); Çetinkaya et al. (1999 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-64-00o28-scheme1.jpg

Experimental

Crystal data

  • C27H31N3
  • M r = 397.55
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-64-00o28-efi1.jpg
  • a = 16.9462 (18) Å
  • b = 6.791 (4) Å
  • c = 21.801 (4) Å
  • β = 104.551 (13)°
  • V = 2428.3 (16) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 0.06 mm−1
  • T = 295 (2) K
  • 0.48 × 0.40 × 0.20 mm

Data collection

  • Rigaku AFC-7S diffractometer
  • Absorption correction: ψ scan (North et al., 1968 [triangle]) T min = 0.963, T max = 0.987
  • 4402 measured reflections
  • 4248 independent reflections
  • 2520 reflections with I > 2σ(I)
  • R int = 0.016
  • 3 standard reflections every 150 reflections intensity decay: none

Refinement

  • R[F 2 > 2σ(F 2)] = 0.061
  • wR(F 2) = 0.188
  • S = 1.02
  • 4248 reflections
  • 272 parameters
  • H-atom parameters constrained
  • Δρmax = 0.24 e Å−3
  • Δρmin = −0.18 e Å−3

Data collection: MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1993 [triangle]); cell refinement: MSC/AFC Diffractometer Control Software; data reduction: TEXSAN (Molecular Structure Corporation, 1999 [triangle]); program(s) used to solve structure: SHELXTL-NT (Bruker, 1998 [triangle]); program(s) used to refine structure: SHELXTL-NT; molecular graphics: SHELXTL-NT and DIAMOND (Brandenburg, 1999 [triangle]); software used to prepare material for publication: SHELXTL-NT and PLATON (Spek, 2003 [triangle]).

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536807060254/hb2609sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536807060254/hb2609Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Acknowledgments

The authors thank FONACIT–MCT, Venezuela, for financial support (project LAB-199700821)

supplementary crystallographic information

Comment

The development of new ligand politopics bearing nitrogen heterocyclic units has been receiving increasing interest in the coordination chemistry of transition-metal based homogeneous catalysis (Togni & Venanzi, 1994). In this context, the planar tridentate–or potentially bidentate–ligand 2,6-bis(imino)pyridine and its derivatives (Orrell et al., 1997) have attracted great attention and the bis(arylimino)pyridine ligand [2,6-(ArN?CR)2C5H3N] by (Alyea & Merrel, 1974). There are several recent examples of reactions catalyzed by complexes bearing the ligand 2,6-bis(arylimino)pyridine ligands such as epoxidation of olefins (Çetinkaya et al., 1999), cyclopropanation of styrene (Bianchini et al., 2000). Specially, it has been nearly a decade since sterically demanding bis(arylimino)pyridine ligands were found to impart transitions metals, iron and cobalt, catalytic activities for olefin polymerization (Small & Brookhart, 1998; Britovsek et al., 1999). Many reports have appared in the literature concerning the effects (sterically and/or electronic) of ligand modifications, to find a structure–activity relationships. The crystal structure of different 2,6-bis(arylimino)pyridine ligands and their transition metal complexes offer the possibilty to compare directly structural parameters. Here we report the synthesis and crystal structure of the title compound, (I), (Fig. 1).

The molecule adopts a nonplanar conformation in which an E configuration around each C?N imine group is observed, likewise the two N atoms display a trans-trans relationship. The conformation of the system N–N–N system is of course different in each case. In general, X-ray structures of bis(arylimino)pyridines reveal that in the solid state the imino nitrogen atoms prefer to be disposed trans with respect to the central pyridine nitrogen (Mentes, et al. 2001; Huang et al., 2006) in order to minimize the interaction between the nitrogen lone pairs. The phenyl rings in (I) are twisted out of the mean plane of the pyridine ring, the mean planes of C8–C13 and C19–C24 being rotated by 63.0 (1)° and 72.58 (8)°, respectively. This molecular conformation is determined by the formation of pairs of intramolecular C—H···N hydrogen bonds, involving methyl groups with the N of the pyridine ring and isopropyl groups with imine groups with a range of distances C···N = 2.799 (3)–2.892 (4) Å (Fig. 2). These interactions lead to the formation of five-membered rings described by graph-set simbol S(5) (Bernstein et al., 1995).

The crystal structure of (I) consists of dimers linked by self-complementary C—H···π interactions related by an inversion centre C15···Cg1 = 3.757 Å; were Cg1 is the centroid of the N1,C1–C5 ring (Fig. 2). Neighbouring dimers are connected through additional C—H···π between phenyl rings (Fig. 3), generating supramolecular sheets parallel to the c axis. Details of geometrical parameters of these hydrogen bonding interactions are summarized in Table 2. Finally, the stacking of adjacent sheets is sustained by hydrophobic methyl-methyl interactions along the a axis (Fig. 4).

Experimental

The tile compound was synthetized by condensation of 2,6-diacetylpiridine (1.63 g, 10 mmol) with 2-iso-propylaniline (2.74 g, 20.3 mmol) in 25 ml dry methanol and five drops of formic acid. The solution was refluxed for 18 h. Upon slow cooling to room temperature and overnight to 273 K. Yellow prisms of (I) were obtained and filtered with a yield 75%. 1H-NMR (300 MHz, CDCl3 ); (δ, p.p.m.) 1.16 (d, 12 H), 2.23(s, 6H), 2.75(sept,2 H), 6. 54(tt, 2H), 7.08(tt, 2 H), 7.20(tt, 2 H), 7.44(dd, 2 H), 7.95(t, 1 H), 8.43(d, 2 H). Elemental analysis calcd. for C27H31N3 (%): C 81.57; H 7.85; N 10.57%. Found: C 81.33; H 7.69; N 10.41%.

Refinement

All H atoms bound to carbon were included in calculated positions (C—H = 0.93–096 Å) and refined as riding with Uiso(H) = 1.2Ueq(C) or 1.5Ueq(methyl C).

Figures

Fig. 1.
Molecular structure of (I) with displacement ellipsoids drawn at the 30% probability level (H atoms omitted for clarity).
Fig. 2.
Ball and stick representation, showing the centrosymmetric dimer generated by C—H···π interactions (dashed lines). Most H atoms have been omitted for clarity.
Fig. 3.
Ball and stick representation, showing side C—H···π interactions between adjacent molecules (dashed lines). Most H atoms have been omitted for clarity.
Fig. 4.
View of the packing of (I) along the b axis

Crystal data

C27H31N3F000 = 856
Mr = 397.55Dx = 1.087 Mg m3
Monoclinic, P21/cMo Kα radiation λ = 0.71069 Å
Hall symbol: -P 2ybcCell parameters from 25 reflections
a = 16.9462 (18) Åθ = 32.2–38.4º
b = 6.791 (4) ŵ = 0.06 mm1
c = 21.801 (4) ÅT = 295 (2) K
β = 104.551 (13)ºPrism, yellow
V = 2428.3 (16) Å30.48 × 0.40 × 0.20 mm
Z = 4

Data collection

Rigaku AFC-7S diffractometerRint = 0.016
Radiation source: normal-focus sealed tubeθmax = 25.0º
Monochromator: graphiteθmin = 1.9º
T = 295(2) Kh = 0→20
ω/2θ scansk = 0→8
Absorption correction: ψ scan(North et al., 1968)l = −25→25
Tmin = 0.963, Tmax = 0.9873 standard reflections
4402 measured reflections every 150 reflections
4248 independent reflections intensity decay: none
2520 reflections with I > 2σ(I)

Refinement

Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.061H-atom parameters constrained
wR(F2) = 0.188  w = 1/[σ2(Fo2) + (0.0887P)2 + 0.6215P] where P = (Fo2 + 2Fc2)/3
S = 1.02(Δ/σ)max < 0.001
4248 reflectionsΔρmax = 0.24 e Å3
272 parametersΔρmin = −0.18 e Å3
Primary atom site location: structure-invariant direct methodsExtinction correction: none

Special details

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)

xyzUiso*/Ueq
N10.05494 (11)0.3071 (3)0.34591 (9)0.0579 (5)
C10.11172 (13)0.2115 (4)0.32418 (11)0.0557 (6)
N2−0.14528 (12)0.2343 (3)0.36370 (10)0.0626 (6)
C20.10199 (15)0.0180 (4)0.30294 (12)0.0628 (7)
H20.1427−0.04460.28850.075*
N30.23456 (12)0.2431 (3)0.29399 (10)0.0677 (6)
C30.03083 (15)−0.0796 (4)0.30372 (12)0.0638 (7)
H30.0233−0.21020.29070.077*
C4−0.02878 (14)0.0191 (4)0.32408 (12)0.0610 (7)
H4−0.0778−0.04280.32380.073*
C5−0.01505 (14)0.2114 (4)0.34492 (11)0.0550 (6)
C6−0.07766 (14)0.3213 (4)0.36847 (12)0.0588 (6)
C7−0.05481 (19)0.5194 (4)0.39720 (18)0.0984 (11)
H7A−0.02090.58590.37450.148*
H7B−0.02560.50430.44080.148*
H7C−0.10330.59550.39480.148*
C8−0.20994 (14)0.3228 (4)0.38484 (13)0.0656 (7)
C9−0.23417 (16)0.2357 (5)0.43497 (13)0.0732 (8)
C10−0.3013 (2)0.3205 (6)0.45150 (17)0.0961 (11)
H10−0.31810.26960.48580.115*
C11−0.3430 (2)0.4763 (7)0.4187 (2)0.1101 (13)
H11−0.38760.52850.43070.132*
C12−0.3195 (2)0.5553 (6)0.3686 (2)0.1071 (12)
H12−0.34830.66010.34610.129*
C13−0.25291 (17)0.4787 (5)0.35161 (16)0.0873 (9)
H13−0.23660.53230.31750.105*
C14−0.1887 (2)0.0594 (5)0.46845 (15)0.0950 (10)
H14−0.1738−0.02040.43560.114*
C15−0.1087 (2)0.1186 (7)0.51467 (17)0.1210 (13)
H15A−0.07770.19960.49320.181*
H15B−0.07800.00250.53060.181*
H15C−0.12010.19090.54930.181*
C16−0.2374 (3)−0.0741 (8)0.5009 (2)0.173 (2)
H16A−0.2872−0.11170.47120.260*
H16B−0.2498−0.00550.53580.260*
H16C−0.2060−0.18980.51620.260*
C170.18765 (14)0.3230 (4)0.32340 (12)0.0599 (6)
C180.20231 (18)0.5140 (4)0.35833 (19)0.0993 (11)
H18A0.15160.58320.35290.149*
H18B0.23950.59250.34200.149*
H18C0.22520.48920.40260.149*
C190.30842 (15)0.3356 (4)0.28902 (13)0.0647 (7)
C200.38249 (15)0.2764 (4)0.32815 (13)0.0679 (7)
C210.45263 (16)0.3592 (5)0.31692 (15)0.0803 (8)
H210.50300.32300.34270.096*
C220.45021 (17)0.4919 (5)0.26932 (16)0.0860 (9)
H220.49830.54390.26300.103*
C230.37679 (18)0.5477 (5)0.23106 (16)0.0920 (10)
H230.37450.63790.19860.110*
C240.30616 (17)0.4692 (5)0.24102 (15)0.0856 (9)
H240.25610.50700.21500.103*
C250.38646 (18)0.1294 (6)0.38095 (15)0.0966 (11)
H250.33020.10350.38280.116*
C260.4307 (3)0.2107 (8)0.4446 (2)0.168 (2)
H26A0.43170.11340.47670.252*
H26B0.40300.32640.45360.252*
H26C0.48550.24430.44390.252*
C270.4219 (5)−0.0611 (8)0.3690 (3)0.236 (4)
H27A0.4222−0.14950.40350.354*
H27B0.4767−0.04100.36560.354*
H27C0.3898−0.11660.33030.354*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
N10.0471 (11)0.0610 (13)0.0652 (12)−0.0048 (10)0.0137 (9)0.0046 (10)
C10.0489 (13)0.0587 (15)0.0586 (14)0.0008 (11)0.0121 (11)0.0055 (12)
N20.0496 (11)0.0725 (14)0.0655 (13)−0.0081 (10)0.0142 (9)−0.0009 (11)
C20.0577 (14)0.0622 (17)0.0693 (16)0.0020 (13)0.0173 (12)−0.0003 (13)
N30.0527 (12)0.0752 (15)0.0763 (14)−0.0045 (11)0.0183 (11)−0.0030 (12)
C30.0672 (16)0.0561 (15)0.0671 (16)−0.0067 (13)0.0149 (13)−0.0039 (13)
C40.0566 (14)0.0612 (16)0.0639 (15)−0.0085 (13)0.0127 (12)0.0029 (13)
C50.0528 (14)0.0574 (15)0.0537 (14)−0.0035 (11)0.0115 (11)0.0052 (11)
C60.0554 (14)0.0571 (15)0.0656 (15)−0.0063 (12)0.0185 (12)0.0044 (12)
C70.084 (2)0.074 (2)0.155 (3)−0.0210 (17)0.062 (2)−0.032 (2)
C80.0478 (14)0.0778 (18)0.0709 (17)−0.0125 (13)0.0142 (12)−0.0101 (15)
C90.0609 (16)0.092 (2)0.0688 (17)−0.0269 (15)0.0208 (13)−0.0149 (16)
C100.076 (2)0.131 (3)0.090 (2)−0.035 (2)0.0366 (18)−0.029 (2)
C110.067 (2)0.135 (3)0.135 (3)−0.006 (2)0.038 (2)−0.036 (3)
C120.071 (2)0.117 (3)0.135 (3)0.016 (2)0.027 (2)−0.005 (3)
C130.0643 (17)0.098 (2)0.101 (2)0.0080 (18)0.0230 (16)0.0075 (19)
C140.103 (2)0.105 (3)0.080 (2)−0.026 (2)0.0289 (18)0.008 (2)
C150.115 (3)0.144 (4)0.092 (2)−0.015 (3)0.005 (2)0.014 (3)
C160.193 (5)0.163 (4)0.175 (5)−0.063 (4)0.069 (4)0.040 (4)
C170.0464 (13)0.0598 (15)0.0724 (16)0.0031 (12)0.0132 (12)0.0073 (13)
C180.0725 (18)0.0693 (19)0.168 (3)−0.0142 (16)0.052 (2)−0.027 (2)
C190.0505 (14)0.0728 (17)0.0737 (17)−0.0027 (13)0.0213 (12)−0.0031 (15)
C200.0533 (15)0.0814 (19)0.0700 (17)0.0003 (14)0.0174 (12)0.0014 (15)
C210.0514 (15)0.095 (2)0.094 (2)0.0048 (15)0.0187 (14)0.0033 (19)
C220.0593 (17)0.095 (2)0.111 (2)−0.0059 (16)0.0351 (17)0.006 (2)
C230.0702 (19)0.097 (2)0.112 (3)0.0009 (17)0.0287 (17)0.030 (2)
C240.0594 (16)0.098 (2)0.099 (2)0.0039 (16)0.0182 (15)0.0255 (19)
C250.0681 (18)0.131 (3)0.089 (2)0.0062 (19)0.0168 (16)0.030 (2)
C260.213 (5)0.196 (5)0.084 (3)0.006 (4)0.016 (3)0.025 (3)
C270.437 (11)0.107 (4)0.206 (6)0.065 (6)0.157 (7)0.059 (4)

Geometric parameters (Å, °)

N1—C11.342 (3)C14—H140.9800
N1—C51.348 (3)C15—H15A0.9600
C1—C21.389 (4)C15—H15B0.9600
C1—C171.496 (3)C15—H15C0.9600
N2—C61.270 (3)C16—H16A0.9600
N2—C81.424 (3)C16—H16B0.9600
C2—C31.380 (3)C16—H16C0.9600
C2—H20.9300C17—C181.493 (4)
N3—C171.263 (3)C18—H18A0.9600
N3—C191.429 (3)C18—H18B0.9600
C3—C41.376 (3)C18—H18C0.9600
C3—H30.9300C19—C241.378 (4)
C4—C51.382 (3)C19—C201.388 (4)
C4—H40.9300C20—C211.391 (4)
C5—C61.490 (3)C20—C251.512 (4)
C6—C71.494 (4)C21—C221.367 (4)
C7—H7A0.9600C21—H210.9300
C7—H7B0.9600C22—C231.366 (4)
C7—H7C0.9600C22—H220.9300
C8—C131.383 (4)C23—C241.376 (4)
C8—C91.392 (4)C23—H230.9300
C9—C101.401 (4)C24—H240.9300
C9—C141.509 (4)C25—C271.476 (6)
C10—C111.369 (5)C25—C261.506 (6)
C10—H100.9300C25—H250.9800
C11—C121.363 (5)C26—H26A0.9600
C11—H110.9300C26—H26B0.9600
C12—C131.375 (4)C26—H26C0.9600
C12—H120.9300C27—H27A0.9600
C13—H130.9300C27—H27B0.9600
C14—C161.516 (5)C27—H27C0.9600
C14—C151.526 (4)
C1—N1—C5117.9 (2)C14—C15—H15C109.5
N1—C1—C2122.6 (2)H15A—C15—H15C109.5
N1—C1—C17117.0 (2)H15B—C15—H15C109.5
C2—C1—C17120.3 (2)C14—C16—H16A109.5
C6—N2—C8121.9 (2)C14—C16—H16B109.5
C3—C2—C1118.8 (2)H16A—C16—H16B109.5
C3—C2—H2120.6C14—C16—H16C109.5
C1—C2—H2120.6H16A—C16—H16C109.5
C17—N3—C19121.6 (2)H16B—C16—H16C109.5
C4—C3—C2119.0 (2)N3—C17—C18126.0 (2)
C4—C3—H3120.5N3—C17—C1116.2 (2)
C2—C3—H3120.5C18—C17—C1117.9 (2)
C3—C4—C5119.3 (2)C17—C18—H18A109.5
C3—C4—H4120.3C17—C18—H18B109.5
C5—C4—H4120.3H18A—C18—H18B109.5
N1—C5—C4122.4 (2)C17—C18—H18C109.5
N1—C5—C6116.9 (2)H18A—C18—H18C109.5
C4—C5—C6120.7 (2)H18B—C18—H18C109.5
N2—C6—C5116.4 (2)C24—C19—C20120.4 (2)
N2—C6—C7125.9 (2)C24—C19—N3119.3 (2)
C5—C6—C7117.6 (2)C20—C19—N3120.0 (2)
C6—C7—H7A109.5C19—C20—C21117.1 (3)
C6—C7—H7B109.5C19—C20—C25121.3 (2)
H7A—C7—H7B109.5C21—C20—C25121.6 (3)
C6—C7—H7C109.5C22—C21—C20122.4 (3)
H7A—C7—H7C109.5C22—C21—H21118.8
H7B—C7—H7C109.5C20—C21—H21118.8
C13—C8—C9121.1 (3)C23—C22—C21119.7 (3)
C13—C8—N2120.0 (2)C23—C22—H22120.2
C9—C8—N2118.5 (3)C21—C22—H22120.2
C8—C9—C10116.5 (3)C22—C23—C24119.4 (3)
C8—C9—C14120.1 (3)C22—C23—H23120.3
C10—C9—C14123.4 (3)C24—C23—H23120.3
C11—C10—C9121.9 (3)C23—C24—C19121.0 (3)
C11—C10—H10119.0C23—C24—H24119.5
C9—C10—H10119.0C19—C24—H24119.5
C12—C11—C10120.4 (3)C27—C25—C26110.7 (4)
C12—C11—H11119.8C27—C25—C20112.8 (3)
C10—C11—H11119.8C26—C25—C20112.1 (3)
C11—C12—C13119.4 (4)C27—C25—H25107.0
C11—C12—H12120.3C26—C25—H25107.0
C13—C12—H12120.3C20—C25—H25107.0
C12—C13—C8120.6 (3)C25—C26—H26A109.5
C12—C13—H13119.7C25—C26—H26B109.5
C8—C13—H13119.7H26A—C26—H26B109.5
C9—C14—C16115.4 (3)C25—C26—H26C109.5
C9—C14—C15111.8 (3)H26A—C26—H26C109.5
C16—C14—C15110.3 (3)H26B—C26—H26C109.5
C9—C14—H14106.2C25—C27—H27A109.5
C16—C14—H14106.2C25—C27—H27B109.5
C15—C14—H14106.2H27A—C27—H27B109.5
C14—C15—H15A109.5C25—C27—H27C109.5
C14—C15—H15B109.5H27A—C27—H27C109.5
H15A—C15—H15B109.5H27B—C27—H27C109.5

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
C7—H7A···N10.962.462.799 (3)100
C14—H14···N20.982.462.830 (4)101
C18—H18A···N10.962.472.819 (3)101
C25—H25···N30.982.392.892 (4)111
C3—H3···Cg1i0.932.753.450 (3)133
C23—H23···Cg2ii0.932.973.801 (4)149
C12—H12···Cg3ii0.933.163.961 (10)146
C15—H15B···Cg1iii0.963.173.757 (13)121
C15—H15C···Cg1iii0.963.443.757 (13)102

Symmetry codes: (i) −x, y−1/2, −z+1/2; (ii) −x, y+1/2, −z+1/2; (iii) −x, −y, −z+1.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: HB2609).

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