organic compounds
2,6-Bis[1-(2-isopropylphenylimino)ethyl]pyridine
aCentro de Química, Instituto Venezolano de Investigaciones Científicas (IVIC), Apartado 21827, Caracas 1020-A, Venezuela
*Correspondence e-mail: gagrifog@cantv.net, abriceno@ivic.ve
The title compound, C27H31N3, has E substitution at each imine double bond where the two N atoms adopt a trans–trans 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 is sustained mainly by C—H⋯π and hydrophobic methyl–methyl interactions.
Related literature
For related literature, see: Alyea & Merrel (1974); Bernstein et al. (1995); Bianchini & Hon Man (2000); Britovsek et al. (1999); Huang et al. (2006); Mentes et al. (2001); Orrell et al. (1997); Small & Brookhart (1998); Togni & Venanzi (1994); Çetinkaya et al. (1999).
Experimental
Crystal data
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Refinement
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Data collection: MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1993); cell MSC/AFC Diffractometer Control Software; data reduction: TEXSAN (Molecular Structure Corporation, 1999); program(s) used to solve structure: SHELXTL-NT (Bruker, 1998); program(s) used to refine structure: SHELXTL-NT; molecular graphics: SHELXTL-NT and DIAMOND (Brandenburg, 1999); software used to prepare material for publication: SHELXTL-NT and PLATON (Spek, 2003).
Supporting information
https://doi.org/10.1107/S1600536807060254/hb2609sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536807060254/hb2609Isup2.hkl
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%.
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).
The development of new ligand politopics bearing nitrogen heterocyclic units has been receiving increasing interest in the coordination chemistry of transition-metal based
(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 (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 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 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
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 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).
of (I) consists of dimers linked by self-complementary C—H···For related literature, see: Alyea & Merrel (1974); Bernstein et al. (1995); Bianchini & Hon Man (2000); Britovsek et al. (1999); Huang et al. (2006); Mentes et al. (2001); Orrell et al. (1997); Small & Brookhart (1998); Togni & Venanzi (1994); Çetinkaya et al. (1999).
Data collection: MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1993); cell
MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1993); data reduction: TEXSAN (Molecular Structure Corporation, 1999); program(s) used to solve structure: SHELXTL-NT (Bruker, 1998); program(s) used to refine structure: SHELXTL-NT (Bruker, 1998); molecular graphics: SHELXTL-NT (Bruker, 1998) and DIAMOND (Brandenburg, 1999); software used to prepare material for publication: SHELXTL-NT (Bruker, 1998) and PLATON (Spek, 2003).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 |
C27H31N3 | F(000) = 856 |
Mr = 397.55 | Dx = 1.087 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71069 Å |
Hall symbol: -P 2ybc | Cell parameters from 25 reflections |
a = 16.9462 (18) Å | θ = 32.2–38.4° |
b = 6.791 (4) Å | µ = 0.06 mm−1 |
c = 21.801 (4) Å | T = 295 K |
β = 104.551 (13)° | Prism, yellow |
V = 2428.3 (16) Å3 | 0.48 × 0.40 × 0.20 mm |
Z = 4 |
Rigaku AFC-7S diffractometer | 2520 reflections with I > 2σ(I) |
Radiation source: normal-focus sealed tube | Rint = 0.016 |
Graphite monochromator | θmax = 25.0°, θmin = 1.9° |
ω/2θ scans | h = 0→20 |
Absorption correction: ψ scan (North et al., 1968) | k = 0→8 |
Tmin = 0.963, Tmax = 0.987 | l = −25→25 |
4402 measured reflections | 3 standard reflections every 150 reflections |
4248 independent reflections | intensity decay: none |
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)] = 0.061 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.188 | H-atom parameters constrained |
S = 1.02 | w = 1/[σ2(Fo2) + (0.0887P)2 + 0.6215P] where P = (Fo2 + 2Fc2)/3 |
4248 reflections | (Δ/σ)max < 0.001 |
272 parameters | Δρmax = 0.24 e Å−3 |
0 restraints | Δρmin = −0.18 e Å−3 |
C27H31N3 | V = 2428.3 (16) Å3 |
Mr = 397.55 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 16.9462 (18) Å | µ = 0.06 mm−1 |
b = 6.791 (4) Å | T = 295 K |
c = 21.801 (4) Å | 0.48 × 0.40 × 0.20 mm |
β = 104.551 (13)° |
Rigaku AFC-7S diffractometer | 2520 reflections with I > 2σ(I) |
Absorption correction: ψ scan (North et al., 1968) | Rint = 0.016 |
Tmin = 0.963, Tmax = 0.987 | 3 standard reflections every 150 reflections |
4402 measured reflections | intensity decay: none |
4248 independent reflections |
R[F2 > 2σ(F2)] = 0.061 | 0 restraints |
wR(F2) = 0.188 | H-atom parameters constrained |
S = 1.02 | Δρmax = 0.24 e Å−3 |
4248 reflections | Δρmin = −0.18 e Å−3 |
272 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 | ||
N1 | 0.05494 (11) | 0.3071 (3) | 0.34591 (9) | 0.0579 (5) | |
C1 | 0.11172 (13) | 0.2115 (4) | 0.32418 (11) | 0.0557 (6) | |
N2 | −0.14528 (12) | 0.2343 (3) | 0.36370 (10) | 0.0626 (6) | |
C2 | 0.10199 (15) | 0.0180 (4) | 0.30294 (12) | 0.0628 (7) | |
H2 | 0.1427 | −0.0446 | 0.2885 | 0.075* | |
N3 | 0.23456 (12) | 0.2431 (3) | 0.29399 (10) | 0.0677 (6) | |
C3 | 0.03083 (15) | −0.0796 (4) | 0.30372 (12) | 0.0638 (7) | |
H3 | 0.0233 | −0.2102 | 0.2907 | 0.077* | |
C4 | −0.02878 (14) | 0.0191 (4) | 0.32408 (12) | 0.0610 (7) | |
H4 | −0.0778 | −0.0428 | 0.3238 | 0.073* | |
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 | −0.0209 | 0.5859 | 0.3745 | 0.148* | |
H7B | −0.0256 | 0.5043 | 0.4408 | 0.148* | |
H7C | −0.1033 | 0.5955 | 0.3948 | 0.148* | |
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 | −0.3181 | 0.2696 | 0.4858 | 0.115* | |
C11 | −0.3430 (2) | 0.4763 (7) | 0.4187 (2) | 0.1101 (13) | |
H11 | −0.3876 | 0.5285 | 0.4307 | 0.132* | |
C12 | −0.3195 (2) | 0.5553 (6) | 0.3686 (2) | 0.1071 (12) | |
H12 | −0.3483 | 0.6601 | 0.3461 | 0.129* | |
C13 | −0.25291 (17) | 0.4787 (5) | 0.35161 (16) | 0.0873 (9) | |
H13 | −0.2366 | 0.5323 | 0.3175 | 0.105* | |
C14 | −0.1887 (2) | 0.0594 (5) | 0.46845 (15) | 0.0950 (10) | |
H14 | −0.1738 | −0.0204 | 0.4356 | 0.114* | |
C15 | −0.1087 (2) | 0.1186 (7) | 0.51467 (17) | 0.1210 (13) | |
H15A | −0.0777 | 0.1996 | 0.4932 | 0.181* | |
H15B | −0.0780 | 0.0025 | 0.5306 | 0.181* | |
H15C | −0.1201 | 0.1909 | 0.5493 | 0.181* | |
C16 | −0.2374 (3) | −0.0741 (8) | 0.5009 (2) | 0.173 (2) | |
H16A | −0.2872 | −0.1117 | 0.4712 | 0.260* | |
H16B | −0.2498 | −0.0055 | 0.5358 | 0.260* | |
H16C | −0.2060 | −0.1898 | 0.5162 | 0.260* | |
C17 | 0.18765 (14) | 0.3230 (4) | 0.32340 (12) | 0.0599 (6) | |
C18 | 0.20231 (18) | 0.5140 (4) | 0.35833 (19) | 0.0993 (11) | |
H18A | 0.1516 | 0.5832 | 0.3529 | 0.149* | |
H18B | 0.2395 | 0.5925 | 0.3420 | 0.149* | |
H18C | 0.2252 | 0.4892 | 0.4026 | 0.149* | |
C19 | 0.30842 (15) | 0.3356 (4) | 0.28902 (13) | 0.0647 (7) | |
C20 | 0.38249 (15) | 0.2764 (4) | 0.32815 (13) | 0.0679 (7) | |
C21 | 0.45263 (16) | 0.3592 (5) | 0.31692 (15) | 0.0803 (8) | |
H21 | 0.5030 | 0.3230 | 0.3427 | 0.096* | |
C22 | 0.45021 (17) | 0.4919 (5) | 0.26932 (16) | 0.0860 (9) | |
H22 | 0.4983 | 0.5439 | 0.2630 | 0.103* | |
C23 | 0.37679 (18) | 0.5477 (5) | 0.23106 (16) | 0.0920 (10) | |
H23 | 0.3745 | 0.6379 | 0.1986 | 0.110* | |
C24 | 0.30616 (17) | 0.4692 (5) | 0.24102 (15) | 0.0856 (9) | |
H24 | 0.2561 | 0.5070 | 0.2150 | 0.103* | |
C25 | 0.38646 (18) | 0.1294 (6) | 0.38095 (15) | 0.0966 (11) | |
H25 | 0.3302 | 0.1035 | 0.3828 | 0.116* | |
C26 | 0.4307 (3) | 0.2107 (8) | 0.4446 (2) | 0.168 (2) | |
H26A | 0.4317 | 0.1134 | 0.4767 | 0.252* | |
H26B | 0.4030 | 0.3264 | 0.4536 | 0.252* | |
H26C | 0.4855 | 0.2443 | 0.4439 | 0.252* | |
C27 | 0.4219 (5) | −0.0611 (8) | 0.3690 (3) | 0.236 (4) | |
H27A | 0.4222 | −0.1495 | 0.4035 | 0.354* | |
H27B | 0.4767 | −0.0410 | 0.3656 | 0.354* | |
H27C | 0.3898 | −0.1166 | 0.3303 | 0.354* |
U11 | U22 | U33 | U12 | U13 | U23 | |
N1 | 0.0471 (11) | 0.0610 (13) | 0.0652 (12) | −0.0048 (10) | 0.0137 (9) | 0.0046 (10) |
C1 | 0.0489 (13) | 0.0587 (15) | 0.0586 (14) | 0.0008 (11) | 0.0121 (11) | 0.0055 (12) |
N2 | 0.0496 (11) | 0.0725 (14) | 0.0655 (13) | −0.0081 (10) | 0.0142 (9) | −0.0009 (11) |
C2 | 0.0577 (14) | 0.0622 (17) | 0.0693 (16) | 0.0020 (13) | 0.0173 (12) | −0.0003 (13) |
N3 | 0.0527 (12) | 0.0752 (15) | 0.0763 (14) | −0.0045 (11) | 0.0183 (11) | −0.0030 (12) |
C3 | 0.0672 (16) | 0.0561 (15) | 0.0671 (16) | −0.0067 (13) | 0.0149 (13) | −0.0039 (13) |
C4 | 0.0566 (14) | 0.0612 (16) | 0.0639 (15) | −0.0085 (13) | 0.0127 (12) | 0.0029 (13) |
C5 | 0.0528 (14) | 0.0574 (15) | 0.0537 (14) | −0.0035 (11) | 0.0115 (11) | 0.0052 (11) |
C6 | 0.0554 (14) | 0.0571 (15) | 0.0656 (15) | −0.0063 (12) | 0.0185 (12) | 0.0044 (12) |
C7 | 0.084 (2) | 0.074 (2) | 0.155 (3) | −0.0210 (17) | 0.062 (2) | −0.032 (2) |
C8 | 0.0478 (14) | 0.0778 (18) | 0.0709 (17) | −0.0125 (13) | 0.0142 (12) | −0.0101 (15) |
C9 | 0.0609 (16) | 0.092 (2) | 0.0688 (17) | −0.0269 (15) | 0.0208 (13) | −0.0149 (16) |
C10 | 0.076 (2) | 0.131 (3) | 0.090 (2) | −0.035 (2) | 0.0366 (18) | −0.029 (2) |
C11 | 0.067 (2) | 0.135 (3) | 0.135 (3) | −0.006 (2) | 0.038 (2) | −0.036 (3) |
C12 | 0.071 (2) | 0.117 (3) | 0.135 (3) | 0.016 (2) | 0.027 (2) | −0.005 (3) |
C13 | 0.0643 (17) | 0.098 (2) | 0.101 (2) | 0.0080 (18) | 0.0230 (16) | 0.0075 (19) |
C14 | 0.103 (2) | 0.105 (3) | 0.080 (2) | −0.026 (2) | 0.0289 (18) | 0.008 (2) |
C15 | 0.115 (3) | 0.144 (4) | 0.092 (2) | −0.015 (3) | 0.005 (2) | 0.014 (3) |
C16 | 0.193 (5) | 0.163 (4) | 0.175 (5) | −0.063 (4) | 0.069 (4) | 0.040 (4) |
C17 | 0.0464 (13) | 0.0598 (15) | 0.0724 (16) | 0.0031 (12) | 0.0132 (12) | 0.0073 (13) |
C18 | 0.0725 (18) | 0.0693 (19) | 0.168 (3) | −0.0142 (16) | 0.052 (2) | −0.027 (2) |
C19 | 0.0505 (14) | 0.0728 (17) | 0.0737 (17) | −0.0027 (13) | 0.0213 (12) | −0.0031 (15) |
C20 | 0.0533 (15) | 0.0814 (19) | 0.0700 (17) | 0.0003 (14) | 0.0174 (12) | 0.0014 (15) |
C21 | 0.0514 (15) | 0.095 (2) | 0.094 (2) | 0.0048 (15) | 0.0187 (14) | 0.0033 (19) |
C22 | 0.0593 (17) | 0.095 (2) | 0.111 (2) | −0.0059 (16) | 0.0351 (17) | 0.006 (2) |
C23 | 0.0702 (19) | 0.097 (2) | 0.112 (3) | 0.0009 (17) | 0.0287 (17) | 0.030 (2) |
C24 | 0.0594 (16) | 0.098 (2) | 0.099 (2) | 0.0039 (16) | 0.0182 (15) | 0.0255 (19) |
C25 | 0.0681 (18) | 0.131 (3) | 0.089 (2) | 0.0062 (19) | 0.0168 (16) | 0.030 (2) |
C26 | 0.213 (5) | 0.196 (5) | 0.084 (3) | 0.006 (4) | 0.016 (3) | 0.025 (3) |
C27 | 0.437 (11) | 0.107 (4) | 0.206 (6) | 0.065 (6) | 0.157 (7) | 0.059 (4) |
N1—C1 | 1.342 (3) | C14—H14 | 0.9800 |
N1—C5 | 1.348 (3) | C15—H15A | 0.9600 |
C1—C2 | 1.389 (4) | C15—H15B | 0.9600 |
C1—C17 | 1.496 (3) | C15—H15C | 0.9600 |
N2—C6 | 1.270 (3) | C16—H16A | 0.9600 |
N2—C8 | 1.424 (3) | C16—H16B | 0.9600 |
C2—C3 | 1.380 (3) | C16—H16C | 0.9600 |
C2—H2 | 0.9300 | C17—C18 | 1.493 (4) |
N3—C17 | 1.263 (3) | C18—H18A | 0.9600 |
N3—C19 | 1.429 (3) | C18—H18B | 0.9600 |
C3—C4 | 1.376 (3) | C18—H18C | 0.9600 |
C3—H3 | 0.9300 | C19—C24 | 1.378 (4) |
C4—C5 | 1.382 (3) | C19—C20 | 1.388 (4) |
C4—H4 | 0.9300 | C20—C21 | 1.391 (4) |
C5—C6 | 1.490 (3) | C20—C25 | 1.512 (4) |
C6—C7 | 1.494 (4) | C21—C22 | 1.367 (4) |
C7—H7A | 0.9600 | C21—H21 | 0.9300 |
C7—H7B | 0.9600 | C22—C23 | 1.366 (4) |
C7—H7C | 0.9600 | C22—H22 | 0.9300 |
C8—C13 | 1.383 (4) | C23—C24 | 1.376 (4) |
C8—C9 | 1.392 (4) | C23—H23 | 0.9300 |
C9—C10 | 1.401 (4) | C24—H24 | 0.9300 |
C9—C14 | 1.509 (4) | C25—C27 | 1.476 (6) |
C10—C11 | 1.369 (5) | C25—C26 | 1.506 (6) |
C10—H10 | 0.9300 | C25—H25 | 0.9800 |
C11—C12 | 1.363 (5) | C26—H26A | 0.9600 |
C11—H11 | 0.9300 | C26—H26B | 0.9600 |
C12—C13 | 1.375 (4) | C26—H26C | 0.9600 |
C12—H12 | 0.9300 | C27—H27A | 0.9600 |
C13—H13 | 0.9300 | C27—H27B | 0.9600 |
C14—C16 | 1.516 (5) | C27—H27C | 0.9600 |
C14—C15 | 1.526 (4) | ||
C1—N1—C5 | 117.9 (2) | C14—C15—H15C | 109.5 |
N1—C1—C2 | 122.6 (2) | H15A—C15—H15C | 109.5 |
N1—C1—C17 | 117.0 (2) | H15B—C15—H15C | 109.5 |
C2—C1—C17 | 120.3 (2) | C14—C16—H16A | 109.5 |
C6—N2—C8 | 121.9 (2) | C14—C16—H16B | 109.5 |
C3—C2—C1 | 118.8 (2) | H16A—C16—H16B | 109.5 |
C3—C2—H2 | 120.6 | C14—C16—H16C | 109.5 |
C1—C2—H2 | 120.6 | H16A—C16—H16C | 109.5 |
C17—N3—C19 | 121.6 (2) | H16B—C16—H16C | 109.5 |
C4—C3—C2 | 119.0 (2) | N3—C17—C18 | 126.0 (2) |
C4—C3—H3 | 120.5 | N3—C17—C1 | 116.2 (2) |
C2—C3—H3 | 120.5 | C18—C17—C1 | 117.9 (2) |
C3—C4—C5 | 119.3 (2) | C17—C18—H18A | 109.5 |
C3—C4—H4 | 120.3 | C17—C18—H18B | 109.5 |
C5—C4—H4 | 120.3 | H18A—C18—H18B | 109.5 |
N1—C5—C4 | 122.4 (2) | C17—C18—H18C | 109.5 |
N1—C5—C6 | 116.9 (2) | H18A—C18—H18C | 109.5 |
C4—C5—C6 | 120.7 (2) | H18B—C18—H18C | 109.5 |
N2—C6—C5 | 116.4 (2) | C24—C19—C20 | 120.4 (2) |
N2—C6—C7 | 125.9 (2) | C24—C19—N3 | 119.3 (2) |
C5—C6—C7 | 117.6 (2) | C20—C19—N3 | 120.0 (2) |
C6—C7—H7A | 109.5 | C19—C20—C21 | 117.1 (3) |
C6—C7—H7B | 109.5 | C19—C20—C25 | 121.3 (2) |
H7A—C7—H7B | 109.5 | C21—C20—C25 | 121.6 (3) |
C6—C7—H7C | 109.5 | C22—C21—C20 | 122.4 (3) |
H7A—C7—H7C | 109.5 | C22—C21—H21 | 118.8 |
H7B—C7—H7C | 109.5 | C20—C21—H21 | 118.8 |
C13—C8—C9 | 121.1 (3) | C23—C22—C21 | 119.7 (3) |
C13—C8—N2 | 120.0 (2) | C23—C22—H22 | 120.2 |
C9—C8—N2 | 118.5 (3) | C21—C22—H22 | 120.2 |
C8—C9—C10 | 116.5 (3) | C22—C23—C24 | 119.4 (3) |
C8—C9—C14 | 120.1 (3) | C22—C23—H23 | 120.3 |
C10—C9—C14 | 123.4 (3) | C24—C23—H23 | 120.3 |
C11—C10—C9 | 121.9 (3) | C23—C24—C19 | 121.0 (3) |
C11—C10—H10 | 119.0 | C23—C24—H24 | 119.5 |
C9—C10—H10 | 119.0 | C19—C24—H24 | 119.5 |
C12—C11—C10 | 120.4 (3) | C27—C25—C26 | 110.7 (4) |
C12—C11—H11 | 119.8 | C27—C25—C20 | 112.8 (3) |
C10—C11—H11 | 119.8 | C26—C25—C20 | 112.1 (3) |
C11—C12—C13 | 119.4 (4) | C27—C25—H25 | 107.0 |
C11—C12—H12 | 120.3 | C26—C25—H25 | 107.0 |
C13—C12—H12 | 120.3 | C20—C25—H25 | 107.0 |
C12—C13—C8 | 120.6 (3) | C25—C26—H26A | 109.5 |
C12—C13—H13 | 119.7 | C25—C26—H26B | 109.5 |
C8—C13—H13 | 119.7 | H26A—C26—H26B | 109.5 |
C9—C14—C16 | 115.4 (3) | C25—C26—H26C | 109.5 |
C9—C14—C15 | 111.8 (3) | H26A—C26—H26C | 109.5 |
C16—C14—C15 | 110.3 (3) | H26B—C26—H26C | 109.5 |
C9—C14—H14 | 106.2 | C25—C27—H27A | 109.5 |
C16—C14—H14 | 106.2 | C25—C27—H27B | 109.5 |
C15—C14—H14 | 106.2 | H27A—C27—H27B | 109.5 |
C14—C15—H15A | 109.5 | C25—C27—H27C | 109.5 |
C14—C15—H15B | 109.5 | H27A—C27—H27C | 109.5 |
H15A—C15—H15B | 109.5 | H27B—C27—H27C | 109.5 |
D—H···A | D—H | H···A | D···A | D—H···A |
C7—H7A···N1 | 0.96 | 2.46 | 2.799 (3) | 100 |
C14—H14···N2 | 0.98 | 2.46 | 2.830 (4) | 101 |
C18—H18A···N1 | 0.96 | 2.47 | 2.819 (3) | 101 |
C25—H25···N3 | 0.98 | 2.39 | 2.892 (4) | 111 |
C3—H3···Cg1i | 0.93 | 2.75 | 3.450 (3) | 133 |
C23—H23···Cg2ii | 0.93 | 2.97 | 3.801 (4) | 149 |
C12—H12···Cg3ii | 0.93 | 3.16 | 3.961 (10) | 146 |
C15—H15B···Cg1iii | 0.96 | 3.17 | 3.757 (13) | 121 |
C15—H15C···Cg1iii | 0.96 | 3.44 | 3.757 (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. |
Experimental details
Crystal data | |
Chemical formula | C27H31N3 |
Mr | 397.55 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 295 |
a, b, c (Å) | 16.9462 (18), 6.791 (4), 21.801 (4) |
β (°) | 104.551 (13) |
V (Å3) | 2428.3 (16) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.06 |
Crystal size (mm) | 0.48 × 0.40 × 0.20 |
Data collection | |
Diffractometer | Rigaku AFC-7S |
Absorption correction | ψ scan (North et al., 1968) |
Tmin, Tmax | 0.963, 0.987 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 4402, 4248, 2520 |
Rint | 0.016 |
(sin θ/λ)max (Å−1) | 0.594 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.061, 0.188, 1.02 |
No. of reflections | 4248 |
No. of parameters | 272 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.24, −0.18 |
Computer programs: MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1993), TEXSAN (Molecular Structure Corporation, 1999), SHELXTL-NT (Bruker, 1998) and DIAMOND (Brandenburg, 1999), SHELXTL-NT (Bruker, 1998) and PLATON (Spek, 2003).
D—H···A | D—H | H···A | D···A | D—H···A |
C7—H7A···N1 | 0.96 | 2.46 | 2.799 (3) | 100 |
C14—H14···N2 | 0.98 | 2.46 | 2.830 (4) | 101 |
C18—H18A···N1 | 0.96 | 2.47 | 2.819 (3) | 101 |
C25—H25···N3 | 0.98 | 2.39 | 2.892 (4) | 111 |
C3—H3···Cg1i | 0.93 | 2.75 | 3.450 (3) | 133 |
C23—H23···Cg2ii | 0.93 | 2.97 | 3.801 (4) | 149 |
C12—H12···Cg3ii | 0.93 | 3.159 | 3.961 (10) | 146 |
C15—H15B···Cg1iii | 0.96 | 3.170 | 3.757 (13) | 121 |
C15—H15C···Cg1iii | 0.96 | 3.436 | 3.757 (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. |
Acknowledgements
The authors thank FONACIT–MCT, Venezuela, for financial support (project LAB-199700821)
References
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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).