N-(4-Methoxy­benzyl­idene)-N′-(2-pyridyl)­hydrazine

Molecules of the title compound (alternative name p-methoxybenzaldehyde 2-pyridyl­hydrazone), C₁₃H₁₃N₃O, adopt an E configuration about the azomethine C=N double bond. Molecules are almost planar, the dihedral angle between the pyridine and methoxy­phenyl rings being only 6.19 (12)°. Pairwise N—H...N hydrogen bonds [R(8) in graph-set notation] link centrosymmetrically related mol­ecules into discrete pairs.

S1. Comment

Hydrazones have been widely studied as chelating ligands for the spectrophotometric and fluorimetric determination of trace metal ions (Katyal & Dutt,1975; Galiano-Roth & Collum, 1988). Many of these compounds have found wide application in medicine, technology and analytical chemistry (Kitaev, 1977). In recent years there has been considerable interest in arlyhydrazone compounds containing a pyridyl group. Hydrazines condense with aldehydes and ketones to give hydrazones, which typically are crystalline compounds with sharp melting points that can therefore be used to identify the aldehydes and ketones from which the hydrazones have been formed (McMurry, 1999). Hydrazones are frequently more suitable than oximes for this purpose, since their greater molecular weight causes a lower solubility in most solvents and they can therefore often be more easily isolated and recrystallized. The hydrazones were obtained by the condensation reaction of aldehydes (or substituted aldehydes) with phenylhydrazine at pH 4–5 (McMurry, 1999).

??In the title compound, (I), ?? the configuration about the azomethine C═N double bond is E, with an N2—N1—C8—C1 torsion angle of −179.54 (19)°. Overall, the molecule is planar, the r.m.s. deviation of the non-H atoms from the least-squares mean plane being only 0.047 Å.

The N1—N2 [1.367 (2) Å] and N1—C8 [1.270 (2) Å] bond distances are comparable to those in the related compounds p-methoxbenzaldehyde isonicotinoyl hydrazone dihydrate (Fun et al., 1996) and p-methoxybenzaldehyde isonicotinoyl hydrazone monohydrate (Shanmuga Sundara Raj et al., 1999) and correspond to single and double bonds, respectively. There is only slight asymmetry of the exocyclic angles at C1 [C2—C1—C8 = 121.72 (19)° and C6—C1—C8 = 120.84 (19)°], while that at C4 is more pronounced [O—C4—C3 = 115.33 (18)° and O—C4—C5 = 125.07 (19)°]. This situation is typical of that found in anisoles and is caused by the tendency of the methoxy group to be coplanar with the phenyl through the conjugation of the O atom with the phenyl ring (Domiano et al., 1979). In (I) the methyl C atom shows no significant deviation from the plane of the phenyl ring. There is also asymmetry in the exocyclic angles at C9 [N2—C9—N3 = 115.37 (17)° and N2—C9—C10 = 121.74 (18)°, respectively]. The dihedral angle between the planes of the pyridine and methoxyphenyl rings is 6.19 (12)°, and these two planes make dihedral angles with the central hydrazone bridge (N2/N1/C8) of 7.59 (3)° and 1.41 (3)°, respectively.

Centrosymmetrically related molecules are linked into discrete pairs by pairwise N2—H2A···N3ⁱ hydrogen bonds [symmetry code: (i) 2 − x,2 − y,-z; graph-set notation R₂²(8)]. The NH···N and N···N distances of 2.27 and 3.119 (4) Å, respectively, are short compared with the relevant van der Waals radii (Bondi, 1964).

S2. Experimental

4-Methoxybenzaldehyde (4.10 g, 0.030 mol) was dissolved in hot methanol (22 ml), and 2-hydrazinopyridine (3.32 g, 0.030 mol) was dissolved in hot methanol (25 ml). The latter solution was added dropwise to the former at 298–303 K. The resulting yellow solid was filtered off, dried and recrystallized after refluxing in hot methanol for 4 h. The yellow crystals thus obtained were filtered off and dried in air.

S3. Refinement

H atoms were placed geometrically at distances of 0.86, 0.93 and 0.96 Å from their parent atoms for N—H, methyl C—H and sp² C—H bonds, respectively. In refinement, a riding model was used for all H atoms with U_iso(H) equal to 1.3U_eq(C, N).

Computing details

Data collection: CAD-4 EXPRESS (Enraf-Nonius, 1993); cell refinement: CAD-4 EXPRESS (Enraf-Nonius, 1993); data reduction: X-RED (Stoe & Cie, 1996); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).

Figures

Fig. 1. The molecular structure and atom-labelling scheme of (I) (ORTEP-3; Farrugia, 1997). Displacement ellipsoids are drawn at the 50% probability level.

(I)

Crystal data

C13H13N3O	F(000) = 480
Mr = 227.26	Dx = 1.283 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 25 reflections
a = 5.5633 (16) Å	θ = 2.2–25.7°
b = 10.4599 (11) Å	µ = 0.09 mm^−1
c = 20.314 (4) Å	T = 293 K
β = 95.51 (2)°	Block, yellow
V = 1176.6 (4) Å^3	0.30 × 0.27 × 0.21 mm
Z = 4

Data collection

Enraf-Nonius CAD-4 diffractometer	Rint = 0.021
Radiation source: fine-focus sealed tube	θmax = 25.7°, θmin = 2.2°
Graphite monochromator	h = −6→0
ω/2θ scans	k = 0→12
2461 measured reflections	l = −24→24
2223 independent reflections	3 standard reflections every 120 min
1177 reflections with I > 2σ(I)	intensity decay: 3%

Refinement

Refinement on F^2	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.042	H-atom parameters constrained
wR(F^2) = 0.128	w = 1/[σ^2(Fo^2) + (0.06P)^2 + 0.057P], where P = (Fo^2 + 2Fc^2)/3
S = 0.99	(Δ/σ)max < 0.001
2223 reflections	Δρmax = 0.11 e Å^−3
154 parameters	Δρmin = −0.17 e Å^−3
Primary atom site location: structure-invariant direct methods

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O	0.0089 (3)	0.97454 (15)	0.34902 (7)	0.0752 (5)
N1	0.5950 (3)	1.06807 (16)	0.10031 (8)	0.0585 (5)
N2	0.7473 (5)	1.06593 (16)	0.05134 (8)	0.0611 (5)
N3	0.8670 (3)	1.14892 (16)	−0.04462 (9)	0.0595 (5)
C1	0.4668 (3)	0.98068 (18)	0.19912 (9)	0.0546 (5)
C2	0.2753 (4)	1.06599 (19)	0.20170 (10)	0.0597 (5)
C3	0.1287 (4)	1.0602 (2)	0.25212 (10)	0.0624 (6)
C4	0.1656 (3)	0.96965 (19)	0.30124 (10)	0.0561 (5)
C5	0.3518 (4)	0.8832 (2)	0.29956 (10)	0.0642 (6)
C6	0.5000 (4)	0.8903 (2)	0.24861 (11)	0.0657 (6)
C7	0.0303 (5)	0.8831 (2)	0.40060 (12)	0.0869 (8)
C8	0.6241 (4)	0.9844 (2)	0.14568 (11)	0.0597 (6)
C9	0.7031 (3)	1.14937 (19)	−0.00065 (10)	0.0526 (5)
C10	0.5007 (4)	1.2284 (2)	−0.00650 (11)	0.0633 (6)
C11	0.4736 (4)	1.3120 (2)	−0.05819 (12)	0.0709 (6)
C12	0.6429 (4)	1.3167 (2)	−0.10354 (12)	0.0718 (6)
C13	0.8321 (4)	1.2328 (2)	−0.09446 (11)	0.0675 (6)
H2A	0.8673	1.0138	0.0530	0.073*
H2	0.2468	1.1275	0.1688	0.072*
H3	0.0025	1.1182	0.2532	0.075*
H5	0.3776	0.8209	0.3322	0.077*
H6	0.6262	0.8321	0.2478	0.079*
H7A	−0.0910	0.8989	0.4302	0.130*
H7B	0.1875	0.8896	0.4244	0.130*
H7C	0.0089	0.7989	0.3822	0.130*
H8	0.7475	0.9247	0.1448	0.072*
H10	0.3869	1.2243	0.0241	0.076*
H11	0.3404	1.3661	−0.0629	0.085*
H12	0.6291	1.3741	−0.1386	0.086*
H13	0.9453	1.2341	−0.1253	0.081*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O	0.067 (9)	0.085 (1)	0.076 (1)	0.011 (9)	0.0211 (8)	0.009 (8)
N1	0.052 (1)	0.059 (1)	0.067 (1)	−0.005 (1)	0.0118 (9)	−0.001 (9)
N2	0.050 (1)	0.062 (1)	0.073 (1)	0.003 (1)	0.0138 (9)	0.009 (9)
N3	0.043 (9)	0.060 (1)	0.077 (1)	0.007 (9)	0.0101 (8)	−0.001 (8)
C1	0.051 (1)	0.050 (1)	0.063 (1)	−0.004 (1)	0.0035 (1)	0.001 (10)
C2	0.059 (1)	0.055 (1)	0.066 (1)	0.003 (1)	0.0057 (1)	0.007 (11)
C3	0.053 (1)	0.061 (1)	0.074 (1)	0.002 (1)	0.0095 (1)	0.010 (11)
C4	0.052 (1)	0.056 (1)	0.061 (1)	−0.003 (1)	0.0053 (1)	−0.005 (11)
C5	0.066 (1)	0.057 (1)	0.069 (1)	0.008 (1)	0.0051 (1)	0.006 (11)
C6	0.062 (1)	0.059 (1)	0.077 (1)	0.004 (1)	0.0086 (1)	0.015 (11)
C7	0.097 (2)	0.080 (2)	0.087 (2)	0.016 (2)	0.0261 (1)	−0.008 (15)
C8	0.054 (1)	0.056 (1)	0.070 (1)	−0.005 (1)	0.0092 (1)	0.005 (10)
C9	0.041 (1)	0.048 (1)	0.068 (1)	−0.007 (1)	0.0033 (1)	−0.003 (9)
C10	0.050 (1)	0.062 (1)	0.079 (1)	−0.002 (1)	0.0106 (1)	0.007 (11)
C11	0.051 (1)	0.065 (1)	0.096 (2)	0.003 (1)	0.0027 (1)	0.010 (11)
C12	0.054 (1)	0.065 (2)	0.095 (2)	0.018 (1)	0.0008 (1)	0.010 (11)
C13	0.047 (1)	0.073 (2)	0.084 (2)	0.012 (1)	0.0123 (1)	−0.004 (12)

Geometric parameters (Å, º)

O—C4	1.367 (2)	C5—C6	1.386 (3)
O—C7	1.415 (2)	C5—H5	0.9300
N1—C8	1.270 (2)	C6—H6	0.9300
N1—N2	1.367 (2)	C7—H7A	0.9600
N2—C9	1.374 (2)	C7—H7B	0.9600
N2—H2A	0.8600	C7—H7C	0.9600
N3—C13	1.340 (2)	C8—H8	0.9300
N3—C9	1.336 (2)	C9—C10	1.393 (3)
C1—C6	1.380 (3)	C10—C11	1.363 (3)
C1—C2	1.394 (3)	C10—H10	0.9300
C1—C8	1.459 (3)	C11—C12	1.380 (3)
C2—C3	1.371 (3)	C11—H11	0.9300
C2—H2	0.9300	C12—C13	1.369 (3)
C3—C4	1.377 (3)	C12—H12	0.9300
C3—H3	0.9300	C13—H13	0.9300
C4—C5	1.378 (3)
C4—O—C7	119.11 (17)	O—C7—H7A	109.5
C8—N1—N2	118.18 (18)	O—C7—H7B	109.5
N1—N2—C9	118.12 (19)	H7A—C7—H7B	109.5
N1—N2—H2A	120.87	O—C7—H7C	109.5
C9—N2—H2A	120.91	H7A—C7—H7C	109.5
C9—N3—C13	116.38 (18)	H7B—C7—H7C	109.5
C6—C1—C2	117.42 (19)	N1—C8—C1	121.00 (19)
C6—C1—C8	120.84 (19)	N1—C8—H8	119.5
C2—C1—C8	121.72 (19)	C1—C8—H8	119.5
C3—C2—C1	120.8 (2)	N2—C9—C10	121.74 (18)
C3—C2—H2	119.9	N3—C9—C10	122.9 (2)
C1—C2—H2	119.9	N3—C9—N2	115.37 (17)
C2—C3—C4	120.9 (2)	C11—C10—C9	118.4 (2)
C2—C3—H3	119.6	C11—C10—H10	121.3
C4—C3—H3	119.6	C9—C10—H10	121.3
O—C4—C5	125.07 (19)	C10—C11—C12	120.3 (2)
O—C4—C3	115.33 (18)	C10—C11—H11	119.83
C3—C4—C5	119.59 (19)	C12—C11—H11	119.85
C4—C5—C6	119.08 (19)	C13—C12—C11	116.9 (2)
C4—C5—H5	120.5	C13—C12—H12	121.8
C6—C5—H5	120.5	C11—C12—H12	121.8
C1—C6—C5	122.2 (2)	N3—C13—C12	125.1 (2)
C1—C6—H6	119.0	C12—C13—H13	117.48
C5—C6—H6	119.0	N3—C13—H13	117.40
C8—N1—N2—C9	174.6 (3)	C6—C1—C8—N1	−179.4 (3)
C6—C1—C2—C3	0.7 (3)	C2—C1—C8—N1	1.5 (5)
C8—C1—C2—C3	179.5 (2)	N1—N2—C9—C10	−4.3 (3)
C1—C2—C3—C4	−0.4 (3)	N1—N2—C9—N3	175.66 (18)
C7—O—C4—C5	−1.9 (5)	C13—N3—C9—C10	2.3 (3)
C7—O—C4—C3	178.56 (19)	C13—N3—C9—N2	−177.69 (18)
C2—C3—C4—O	179.5 (3)	N2—C9—C10—C11	177.7 (2)
C2—C3—C4—C5	−0.3 (3)	N3—C9—C10—C11	−2.3 (3)
O—C4—C5—C6	−178.9 (3)	C9—C10—C11—C12	0.4 (3)
C3—C4—C5—C6	0.7 (3)	C10—C11—C12—C13	1.2 (3)
C2—C1—C6—C5	−0.3 (3)	C11—C12—C13—N3	−1.3 (3)
C8—C1—C6—C5	−179.1 (2)	C9—N3—C13—C12	−0.5 (3)
C4—C5—C6—C1	−0.2 (6)	C11—C12—C13—N3	−1.3 (3)
N2—N1—C8—C1	−179.54 (19)	C9—N3—C13—C12	−0.5 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2A···N3^i	0.86	2.27	3.119 (4)	169

Symmetry code: (i) −x+2, −y+2, −z.