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In the title compound, C24H18N4, each Schiff base molecule is centrosymmetric and interacts with four neighbours via four C—H(Ph)...N(py) hydrogen bonds (py is pyridyl) and four C—H(py)...π(Ph) hydrogen bonds, leading to an interesting two-dimensional hydrogen-bonded layer architecture.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270104034079/fr1518sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270104034079/fr1518Isup2.hkl
Contains datablock I

CCDC reference: 264813

Comment top

The hydrogen bond is a subject that has attracted intense attention, due to its great importance in a vast number of chemical, biological and materials systems (Steiner, 2002). The weak hydrogen bond of the C—H···X type (X = O, N, and π acceptors) has been well established in structural, supramolecular and biological chemistry, and it has been widely used as a tool for crystal engineering of organic and organometallic solids (Desiraju & Steiner, 1999; Desiraju, 1996; Braga & Grepioni, 2000; Braga et al., 1998). In this paper, we report the synthesis and crystal structure of a Schiff base compound, 1,4-tris(4-pyridyl)-1,4-diphenyl-2,3-diaza-1,3-butadiene, (I), in which the C—H···N and C—H···π hydrogen bonds act as the dominant forces to organize the molecules into an interesting two-dimensional supramolecular layer architecture.

A perspective view of the molecule of (I), with the atom-labelling scheme, is depicted in Fig. 1. Each molecule is centrosymmetric, with the inversion centre at the mid-point of the N—N bond. The aromatic C—C bond lengths in the pyridyl and phenyl rings fall in the narrow range of 1.372 (2)–1.3938 (18) Å, and the two C—N bonds of the pyridyl rings are 1.333 (2) and 1.3262 (19) Å. The CN bond length (C12—N2) is 1.2882 (15) Å, and the central N—N bond (N2—N2A) is 1.4074 (19) Å. All the data are in good agreement with the chemical structure of the Schiff base, shown in the scheme.

The molecule is distorted severely from planarity. Neither the pyridyl nor the phenyl ring is coplanar with the central CN—NC planar spacer, the dihedral angles being 69.54 (9) and 32.25 (12)°, respectively, while the dihedral angle between the pyridyl and phenyl rings is 85.07 (5)°.

Of particular interest are the intermolecular C—H···N and C—H···π hydrogen bonds organizing the molecules of (I) into a supramolecular architecture. The molecule contains two equivalent phenyl rings and two equivalent pyridyl rings, and all these aromatic groups are involved in intermolecular C—H···N and C—H···π hydrogen bonding. In the c direction, each pyridyl N atom of one molecule forms a hydrogen bond with a phenyl C—H group from a neighbouring molecule (C2—H···N1B; Fig. 2). Thus, each molecule interacts with two neighbours via four equivalent C—H···N hydrogen bonds, generating infinite hydrogen-bonded chains parallel to the c direction. The relevant geometrical parameters are 3.483 (2) Å for the C···N distance, 2.553 (17) Å for the H···N distance and 157.2 (12)° for the C—H···N angle.

In the a direction, each pyridyl C11—H group from one molecule points to the centre of the neighbouring phenyl ring from another molecule, suggesting the formation of C—H···π hydrogen bonds (Fig. 2). Consequently, each molecule interacts with two neighbours via four equivalent C—H···π hydrogen bonds, generating infinite hydrogen-bonded chains parallel to the a direction. In this hydrogen-bonding motif, the distances of the H and C atoms to the centroid (Cg) of the phenyl ring, H···Cg and C···Cg, are 2.66 and 3.60 Å, respectively, within the literature range for the C—H···Ph interaction (Braga et al., 1998). The ω(H) angle defined by Desiraju & Steiner (1999), between the H···Cg line and the normal axis of the phenyl ring, is only 2.5°, and the C—H···Cg angle is 176.5°, very close to 180°, suggesting an almost linear and centred C—H···Ph hydrogen bond (Desiraju & Steiner, 1999).

As can be seen from Fig. 2, these two different types of weak hydrogen bonds, which propagate along different directions (the c and a directions), operate concurrently to organize the molecules into an interesting two-dimensional hydrogen-bonded layer extending parallel to the ac plane, in which each molecule interacts with four neighbours via a total of eight hydrogen bonds. The layers are stacked down the b direction in a parallel and featureless fashion, without evident indications of hydrogen bonding or ππ interactions.

To summarize, we have synthesized and characterized a new symmetric Schiff base bearing two pyridyl and two phenyl groups. All these groups are involved in intermolecular C—H···N and C—H···π hydrogen bonds, which serve as the dominant and concurrent forces to organize the molecules into an interesting two-dimensional hydrogen-bonded layer architecture.

Experimental top

The title compound was synthesized by the condensation reaction of 4-benzoylpyridine with hydrazine. An ethanol solution (10 ml) of 4-benzoylpyridine (Acros; 10 mmol) was mixed with hydrazine hydrate (Acros; 5 mmol) and two drops of formic acid. The mixture was refluxed for 12 h, resulting in a clear yellow solution. The solvent was removed under reduced pressure to obtain a yellow residue, which was crystallized from ethanol to obtain a yellow microcrystalline product. Single crystals of (I) were obtained by slow evaporation of a methanol solution of the product. Analysis calculated for C24H18N4: C 79.54, H 5.01, N 15.46%; found: C 79.28, H 5.05, N 15.65%. Main IR bands (cm−1): 3099 (w), 3055 (m), 3032 (m), 3016 (w), 2984 (w), 1601 (m), 1588 (s), 1568 (m), 1543 (m), 1489 (m), 1444 (m), 1410 (m), 1328 (m), 1317 (m), 1307 (m), 1218 (m), 992 (m), 819 (s), 777 (s), 691 (s).

Refinement top

All H atoms were located from the difference Fourier map and refined isotropically. The refined C—H distances fall in the range 0.939 (16)–0.994 (18) Å.

Computing details top

Data collection: COLLECT (Nonius, 1998); cell refinement: HKL SCALEPACK (Otwinowski & Minor, 1997); data reduction: HKL DENZO (Otwinowski & Minor, 1997) and maXus (Mackay et al., 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997a); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997a); molecular graphics: SHELXTL (Sheldrick, 1997b); software used to prepare material for publication: SHELXL97.

Figures top
[Figure 1] Fig. 1. A perspective view of the molecular structure of (I). Displacement ellipsoids are drawn at the 50% probability level. [Symmetry code: (i) 1 − x, 1 − y, −z.]
[Figure 2] Fig. 2. A perspective view of the two-dimensional network built up by the C—H···N and C—H···π hydrogen bonds. For the sake of clarity, H atoms, except for those involved in hydrogen bonding, have been omitted. [Symmetry codes: (ii) 1 − x, 1 − y, 1 − z; (iii) x − 1, y, z; (iv) 1 + x, y, z.]
[Figure 3] Fig. 3. Please provide missing caption, including symmetry codes.
1,4-Diphenyl-1,4-di-4-pyridyl-2,3-diaza-1,3-butadiene top
Crystal data top
C24H18N4Z = 1
Mr = 362.42F(000) = 190
Triclinic, P1Dx = 1.293 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 6.1251 (12) ÅCell parameters from 6326 reflections
b = 7.3258 (15) Åθ = 3.4–27.5°
c = 10.456 (2) ŵ = 0.08 mm1
α = 93.35 (3)°T = 293 K
β = 91.28 (3)°Rod, yellow
γ = 96.00 (3)°0.4 × 0.15 × 0.15 mm
V = 465.62 (16) Å3
Data collection top
Nonius KappaCCD area-detector
diffractometer
2101 independent reflections
Radiation source: fine-focus sealed tube1637 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.036
Detector resolution: 0.76 pixels mm-1θmax = 27.5°, θmin = 3.5°
ϕ and ω scansh = 77
Absorption correction: empirical (using intensity measurements)
(Blessing, 1995, 1997)
k = 99
Tmin = 0.969, Tmax = 0.998l = 1313
10946 measured reflections
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.041All H-atom parameters refined
wR(F2) = 0.110 w = 1/[σ2(Fo2) + (0.0535P)2 + 0.0573P]
where P = (Fo2 + 2Fc2)/3
S = 1.05(Δ/σ)max < 0.001
2101 reflectionsΔρmax = 0.19 e Å3
164 parametersΔρmin = 0.15 e Å3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 1997a), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.080 (13)
Crystal data top
C24H18N4γ = 96.00 (3)°
Mr = 362.42V = 465.62 (16) Å3
Triclinic, P1Z = 1
a = 6.1251 (12) ÅMo Kα radiation
b = 7.3258 (15) ŵ = 0.08 mm1
c = 10.456 (2) ÅT = 293 K
α = 93.35 (3)°0.4 × 0.15 × 0.15 mm
β = 91.28 (3)°
Data collection top
Nonius KappaCCD area-detector
diffractometer
2101 independent reflections
Absorption correction: empirical (using intensity measurements)
(Blessing, 1995, 1997)
1637 reflections with I > 2σ(I)
Tmin = 0.969, Tmax = 0.998Rint = 0.036
10946 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0410 restraints
wR(F2) = 0.110All H-atom parameters refined
S = 1.05Δρmax = 0.19 e Å3
2101 reflectionsΔρmin = 0.15 e Å3
164 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 > 2σ(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
C10.14151 (19)0.29594 (16)0.13918 (11)0.0344 (3)
C20.1134 (2)0.21261 (19)0.25500 (13)0.0444 (3)
H20.224 (3)0.242 (2)0.3250 (16)0.059 (4)*
C30.0681 (3)0.0872 (2)0.27047 (16)0.0551 (4)
H30.085 (3)0.028 (3)0.3513 (19)0.079 (6)*
C40.2246 (3)0.0470 (2)0.17276 (16)0.0563 (4)
H40.348 (3)0.038 (2)0.1856 (17)0.070 (5)*
C50.1993 (2)0.1312 (2)0.05942 (15)0.0499 (4)
H50.312 (3)0.103 (2)0.0108 (17)0.063 (5)*
C60.0172 (2)0.25409 (18)0.04132 (13)0.0402 (3)
H60.005 (2)0.315 (2)0.0395 (16)0.054 (4)*
C70.43509 (19)0.54309 (16)0.23360 (11)0.0339 (3)
C80.3185 (2)0.6749 (2)0.29159 (13)0.0476 (3)
H80.173 (3)0.695 (2)0.2589 (15)0.058 (4)*
C90.4109 (3)0.7808 (2)0.39721 (14)0.0570 (4)
H90.329 (3)0.878 (3)0.4368 (18)0.080 (6)*
C100.7139 (2)0.6298 (2)0.39438 (13)0.0511 (4)
H100.859 (3)0.616 (2)0.4341 (17)0.065 (5)*
C110.6387 (2)0.5212 (2)0.28614 (13)0.0450 (3)
H110.726 (3)0.434 (2)0.2508 (15)0.056 (4)*
C120.33808 (18)0.42629 (16)0.11961 (11)0.0328 (3)
N10.6060 (2)0.75934 (18)0.44989 (11)0.0547 (3)
N20.40933 (16)0.43361 (14)0.00485 (9)0.0375 (3)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0346 (6)0.0335 (6)0.0343 (6)0.0020 (5)0.0014 (5)0.0020 (5)
C20.0470 (7)0.0465 (7)0.0386 (7)0.0013 (6)0.0025 (6)0.0042 (6)
C30.0609 (9)0.0494 (8)0.0538 (9)0.0057 (7)0.0116 (7)0.0099 (7)
C40.0481 (8)0.0451 (8)0.0720 (10)0.0118 (6)0.0110 (7)0.0007 (7)
C50.0401 (7)0.0467 (8)0.0596 (9)0.0038 (6)0.0052 (6)0.0079 (7)
C60.0392 (7)0.0392 (7)0.0410 (7)0.0020 (5)0.0032 (5)0.0020 (5)
C70.0358 (6)0.0358 (6)0.0287 (6)0.0028 (5)0.0025 (4)0.0010 (4)
C80.0445 (7)0.0551 (8)0.0421 (7)0.0081 (6)0.0007 (6)0.0093 (6)
C90.0662 (10)0.0565 (9)0.0464 (8)0.0080 (7)0.0024 (7)0.0157 (7)
C100.0478 (8)0.0608 (9)0.0420 (7)0.0024 (7)0.0102 (6)0.0007 (6)
C110.0426 (7)0.0505 (8)0.0412 (7)0.0061 (6)0.0038 (5)0.0040 (6)
C120.0325 (6)0.0350 (6)0.0305 (6)0.0032 (5)0.0004 (4)0.0008 (4)
N10.0647 (8)0.0570 (8)0.0383 (6)0.0064 (6)0.0042 (5)0.0073 (5)
N20.0368 (5)0.0413 (6)0.0324 (5)0.0042 (4)0.0017 (4)0.0017 (4)
Geometric parameters (Å, º) top
C1—C21.3938 (18)C7—C81.3803 (18)
C1—C61.3938 (17)C7—C121.4996 (16)
C1—C121.4821 (17)C8—C91.386 (2)
C2—C31.385 (2)C8—H80.978 (16)
C2—H20.986 (16)C9—N11.333 (2)
C3—C41.382 (2)C9—H90.994 (18)
C3—H30.98 (2)C10—N11.3262 (19)
C4—C51.372 (2)C10—C111.3861 (19)
C4—H40.944 (18)C10—H100.989 (17)
C5—C61.3818 (19)C11—H110.939 (16)
C5—H50.994 (17)C12—N21.2882 (15)
C6—H60.985 (17)N2—N2i1.4074 (19)
C7—C111.3799 (18)
C2—C1—C6119.09 (12)C11—C7—C12122.11 (11)
C2—C1—C12120.62 (11)C8—C7—C12120.22 (11)
C6—C1—C12120.29 (11)C7—C8—C9119.26 (13)
C3—C2—C1119.90 (13)C7—C8—H8120.9 (10)
C3—C2—H2120.5 (9)C9—C8—H8119.9 (10)
C1—C2—H2119.6 (9)N1—C9—C8123.67 (14)
C4—C3—C2120.44 (14)N1—C9—H9117.4 (11)
C4—C3—H3120.3 (11)C8—C9—H9119.0 (11)
C2—C3—H3119.2 (11)N1—C10—C11124.37 (14)
C5—C4—C3119.80 (13)N1—C10—H10115.3 (10)
C5—C4—H4121.1 (11)C11—C10—H10120.3 (10)
C3—C4—H4119.1 (11)C7—C11—C10118.77 (13)
C4—C5—C6120.59 (14)C7—C11—H11121.7 (9)
C4—C5—H5119.9 (10)C10—C11—H11119.5 (9)
C6—C5—H5119.5 (10)N2—C12—C1117.23 (10)
C5—C6—C1120.16 (13)N2—C12—C7124.96 (11)
C5—C6—H6121.9 (9)C1—C12—C7117.79 (10)
C1—C6—H6118.0 (9)C10—N1—C9116.24 (12)
C11—C7—C8117.65 (12)C12—N2—N2i112.96 (12)
C6—C1—C2—C31.38 (19)N1—C10—C11—C72.2 (2)
C12—C1—C2—C3178.17 (12)C2—C1—C12—N2148.94 (12)
C1—C2—C3—C41.5 (2)C6—C1—C12—N230.60 (16)
C2—C3—C4—C50.4 (2)C2—C1—C12—C732.72 (16)
C3—C4—C5—C60.9 (2)C6—C1—C12—C7147.74 (11)
C4—C5—C6—C11.0 (2)C11—C7—C12—N269.45 (17)
C2—C1—C6—C50.15 (18)C8—C7—C12—N2112.11 (15)
C12—C1—C6—C5179.40 (11)C11—C7—C12—C1112.35 (13)
C11—C7—C8—C91.2 (2)C8—C7—C12—C166.09 (16)
C12—C7—C8—C9179.71 (13)C11—C10—N1—C91.3 (2)
C7—C8—C9—N12.2 (2)C8—C9—N1—C100.9 (2)
C8—C7—C11—C100.83 (19)C1—C12—N2—N2i177.58 (11)
C12—C7—C11—C10177.65 (12)C7—C12—N2—N2i0.63 (19)
Symmetry code: (i) x+1, y+1, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C2—H2···N1ii0.986 (16)2.553 (17)3.483 (2)157.2 (12)
Symmetry code: (ii) x+1, y+1, z+1.

Experimental details

Crystal data
Chemical formulaC24H18N4
Mr362.42
Crystal system, space groupTriclinic, P1
Temperature (K)293
a, b, c (Å)6.1251 (12), 7.3258 (15), 10.456 (2)
α, β, γ (°)93.35 (3), 91.28 (3), 96.00 (3)
V3)465.62 (16)
Z1
Radiation typeMo Kα
µ (mm1)0.08
Crystal size (mm)0.4 × 0.15 × 0.15
Data collection
DiffractometerNonius KappaCCD area-detector
diffractometer
Absorption correctionEmpirical (using intensity measurements)
(Blessing, 1995, 1997)
Tmin, Tmax0.969, 0.998
No. of measured, independent and
observed [I > 2σ(I)] reflections
10946, 2101, 1637
Rint0.036
(sin θ/λ)max1)0.649
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.041, 0.110, 1.05
No. of reflections2101
No. of parameters164
H-atom treatmentAll H-atom parameters refined
Δρmax, Δρmin (e Å3)0.19, 0.15

Computer programs: COLLECT (Nonius, 1998), HKL SCALEPACK (Otwinowski & Minor, 1997), HKL DENZO (Otwinowski & Minor, 1997) and maXus (Mackay et al., 1998), SHELXS97 (Sheldrick, 1997a), SHELXL97 (Sheldrick, 1997a), SHELXTL (Sheldrick, 1997b), SHELXL97.

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C2—H2···N1i0.986 (16)2.553 (17)3.483 (2)157.2 (12)
Symmetry code: (i) x+1, y+1, z+1.
 

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