4-Hydro­xy-3-methoxy­benz­aldehyde 4,5-di­azafluoren-9-yl­idene­hydrazone

The whole mol­ecule of the title compound, C₁₉H₁₄N₄O₂, is essentially planar, with a highly conjugated π system. In the crystal, the mol­ecules are packed as chains along the [011] direction connected by O—H...N intermolecular hydrogen bonds.

S1. Comment

Schiff-base compounds having extensively conjugated π-electron systems have been reported to display second harmonic generations (Messier et al., 1991; Zyss, 1994). As part of our work in search and study of new materials for nonlinear optical application, we report the crystal structure of the title compound, (I). \sch

Bond lengths and angles observed in this structure agree well with the related structures (Lu et al., 1995, 1997). The diazafluorene substituent does not show relevant distortion from planarity and from C₂ symmetry. The whole molecule is essentially planar. The C—N bond lengths in the hydrazone moiety are short compared with those observed in related compound, p-dimethylaminobenzaldehyde 4,5-diaza-9-fluorenylidene hydrazone monohydrate (Lu et al., 1995). This indicates that the π-conjugation along the central hydrazone chain is higher in the present compound. The phenyl group is in anti-periplanar orientation with respect to the N4—C12 bond.

While substitution at the phenyl C13 is angularly symmetric, C12—C13—C18 = 120.5 (2) and C12—C13—C14 = 120.0 (2)°, substitution at the diazafluorenyl C11 shows quite a relevant angular asymmetry; the C1—C11—N3 = 133.1 (2)° angle being larger than C10—C11—N3, 120.8 (2)°. This asymmetry seems to be caused by the tendency of the central hydrazone system to be coplanar with that of the fluorenyl due to π-conjugation, and steric hindrance involving the C2—H group with N4 [C2···N4 = 3.004 (4), H2···N4 = 2.53 Å] and C9—H with N3 [C9···N3 = 3.054 (3), H9···N3 = 2.90 Å]. The asymmetry of the exocyclic angles at C17 [C16—C17—O2 = 116.2 (2) and C18—C17—O2 = 124.4 (2)°] is caused by the tendency the methoxy group has to be coplanar with the phenyl ring as usually found in anisoles. This tendency can be justified by some degree of conjugation between O and phenyl which is shown by some shortening of the C_ar—O = 1.367 (3) Å bond (Domiano et al., 1979). Some hindrance occurs between one of the methyl H atoms with that bound to C18: H19C···H18 = 2.15 Å. The same kind of asymmetry is observed for the exocyclic angles at C16 [C17—C16—O1 = 117.2 (2) and C15—C16—O1 = 123.6 (2)°] which is common whith phenols, the C16—O1 bond being 1.358 (3) and the H1···H15 contact 2.30 Å.

The dihedral angles formed by the planes of the diazafluorene group and the phenyl ring with the central hydrazone (N3, N4, C12) bridge are 4.6 (2) and 3.0 (2)° and 7.29 (5)° between each other. In the crystal, the molecules are packed as chains along the [011] direction connected by O—H···N intermolecular hydrogen bonds.

S2. Experimental

The synthesis of the compound was carried out by reaction of 3-methoxy-4-hydroxybenzaldehyde and 4,5-diazafluorene-9-hydrazine in ethanol solution under reflux for 5 h. Single crystals were obtained by recrystallization from ethanol.

S3. Refinement

Collection of intensity data was as described by Shanmuga Sundara Raj et al. (1999). The Friedel pairs were not included in the refinement.

Computing details

Data collection: SMART (Siemens, 1996); cell refinement: SAINT (Siemens, 1996); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 1997); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL, PARST (Nardelli, 1995) and PLATON (Spek, 1990).

Figures

Fig. 1. The structure of title compound showing 50% probability displacement ellipsoids and the atom-numbering scheme.

3-Methoxy-4-hydroxyl-benzaldehyde 4,5-Diaza-9-fluorenylidenehydrazone

Crystal data

C19H14N4O2	Dx = 1.371 Mg m^−3
Mr = 330.34	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Pna21	Cell parameters from 5698 reflections
a = 7.5130 (2) Å	θ = 1.5–28.3°
b = 26.9091 (5) Å	µ = 0.09 mm^−1
c = 7.9141 (1) Å	T = 293 K
V = 1599.98 (6) Å^3	Slab, yellow
Z = 4	0.38 × 0.30 × 0.12 mm
F(000) = 688

Data collection

Siemens SMART CCD area detector diffractometer	1577 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.082
Graphite monochromator	θmax = 28.3°, θmin = 1.5°
Detector resolution: 8.33 pixels mm^-1	h = −9→10
ω scans	k = −34→35
10894 measured reflections	l = −10→6
2115 independent reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.041	H-atom parameters constrained
wR(F^2) = 0.093	w = 1/[σ^2(Fo^2) + (0.0474P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 0.93	(Δ/σ)max < 0.001
2115 reflections	Δρmax = 0.18 e Å^−3
227 parameters	Δρmin = −0.17 e Å^−3
1 restraint	Extinction correction: SHELXTL (Sheldrick, 1997), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0096 (18)

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 (Ų)

	x	y	z	Uiso*/Ueq
O1	0.7711 (2)	0.43423 (6)	0.4619 (3)	0.0499 (5)
H1	0.8081	0.4177	0.5414	0.075*
O2	0.6694 (2)	0.49751 (6)	0.2260 (2)	0.0512 (5)
N1	0.6434 (3)	0.80233 (8)	−0.0038 (3)	0.0445 (5)
N2	0.7414 (3)	0.87917 (7)	0.2684 (3)	0.0440 (5)
N3	0.8335 (3)	0.71907 (7)	0.5134 (3)	0.0389 (5)
N4	0.8097 (3)	0.66955 (7)	0.4617 (3)	0.0404 (5)
C1	0.7257 (3)	0.74481 (8)	0.2208 (3)	0.0334 (5)
C2	0.6917 (3)	0.70404 (9)	0.1185 (4)	0.0434 (6)
H2	0.7085	0.6717	0.1571	0.052*
C3	0.6319 (4)	0.71351 (10)	−0.0425 (4)	0.0494 (7)
H3	0.6060	0.6872	−0.1146	0.059*
C4	0.6100 (4)	0.76198 (10)	−0.0983 (4)	0.0493 (7)
H4	0.5696	0.7668	−0.2081	0.059*
C5	0.7009 (3)	0.79257 (8)	0.1516 (3)	0.0342 (5)
C6	0.7472 (3)	0.82960 (8)	0.2821 (3)	0.0336 (5)
C7	0.7863 (4)	0.90388 (9)	0.4103 (4)	0.0524 (7)
H7	0.7842	0.9384	0.4059	0.063*
C8	0.8350 (3)	0.88232 (9)	0.5610 (4)	0.0486 (6)
H8	0.8624	0.9020	0.6542	0.058*
C9	0.8426 (3)	0.83119 (9)	0.5722 (4)	0.0420 (6)
H9	0.8760	0.8154	0.6717	0.050*
C10	0.7984 (3)	0.80459 (8)	0.4293 (3)	0.0332 (5)
C11	0.7893 (3)	0.75057 (8)	0.3973 (3)	0.0332 (5)
C12	0.8597 (3)	0.63852 (8)	0.5753 (3)	0.0370 (5)
H12	0.9087	0.6500	0.6759	0.044*
C13	0.8398 (3)	0.58524 (8)	0.5469 (3)	0.0358 (5)
C14	0.8966 (3)	0.55167 (8)	0.6688 (3)	0.0425 (6)
H14	0.9485	0.5629	0.7684	0.051*
C15	0.8747 (3)	0.50077 (9)	0.6398 (3)	0.0431 (6)
H15	0.9134	0.4783	0.7210	0.052*
C16	0.7975 (3)	0.48325 (8)	0.4942 (3)	0.0376 (6)
C17	0.7430 (3)	0.51746 (9)	0.3687 (3)	0.0372 (6)
C18	0.7640 (3)	0.56748 (8)	0.3968 (3)	0.0362 (5)
H18	0.7273	0.5900	0.3147	0.043*
C19	0.6391 (4)	0.53099 (10)	0.0897 (4)	0.0563 (7)
H19A	0.5873	0.5133	−0.0035	0.084*
H19B	0.7501	0.5454	0.0551	0.084*
H19C	0.5595	0.5568	0.1257	0.084*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0745 (12)	0.0243 (9)	0.0509 (12)	0.0000 (7)	0.0045 (10)	0.0032 (8)
O2	0.0747 (12)	0.0345 (10)	0.0444 (12)	−0.0015 (8)	−0.0094 (10)	−0.0049 (8)
N1	0.0568 (12)	0.0438 (12)	0.0329 (13)	0.0005 (9)	−0.0045 (11)	0.0055 (9)
N2	0.0592 (12)	0.0269 (11)	0.0460 (14)	−0.0008 (8)	−0.0061 (11)	0.0048 (9)
N3	0.0561 (11)	0.0250 (10)	0.0356 (13)	−0.0008 (8)	−0.0094 (10)	0.0022 (8)
N4	0.0584 (12)	0.0258 (10)	0.0369 (12)	0.0009 (8)	−0.0112 (10)	0.0008 (8)
C1	0.0384 (11)	0.0305 (12)	0.0313 (13)	0.0004 (9)	−0.0009 (11)	0.0018 (10)
C2	0.0562 (15)	0.0331 (13)	0.0408 (16)	0.0012 (11)	−0.0119 (12)	−0.0045 (11)
C3	0.0645 (15)	0.0420 (15)	0.0417 (16)	0.0029 (12)	−0.0118 (13)	−0.0098 (12)
C4	0.0582 (16)	0.0557 (16)	0.0340 (15)	0.0003 (12)	−0.0088 (13)	−0.0018 (13)
C5	0.0386 (12)	0.0328 (12)	0.0314 (14)	−0.0001 (9)	−0.0001 (11)	0.0027 (10)
C6	0.0413 (12)	0.0272 (11)	0.0324 (13)	−0.0002 (9)	−0.0008 (11)	0.0017 (9)
C7	0.0736 (17)	0.0245 (12)	0.0589 (19)	−0.0007 (12)	−0.0112 (15)	−0.0026 (13)
C8	0.0654 (16)	0.0342 (14)	0.0461 (16)	0.0011 (12)	−0.0107 (15)	−0.0079 (13)
C9	0.0556 (14)	0.0337 (13)	0.0367 (15)	−0.0008 (11)	−0.0072 (12)	−0.0025 (11)
C10	0.0408 (11)	0.0272 (11)	0.0317 (14)	0.0008 (9)	−0.0032 (10)	0.0007 (10)
C11	0.0392 (12)	0.0293 (11)	0.0312 (13)	−0.0006 (9)	−0.0019 (11)	0.0004 (10)
C12	0.0469 (13)	0.0317 (12)	0.0325 (13)	−0.0013 (9)	−0.0062 (11)	0.0013 (11)
C13	0.0435 (12)	0.0270 (11)	0.0367 (14)	−0.0009 (9)	−0.0054 (11)	0.0039 (10)
C14	0.0544 (14)	0.0349 (13)	0.0381 (14)	−0.0038 (10)	−0.0104 (12)	0.0090 (11)
C15	0.0510 (13)	0.0312 (12)	0.0471 (16)	0.0020 (10)	−0.0044 (13)	0.0159 (11)
C16	0.0447 (12)	0.0246 (12)	0.0435 (16)	0.0001 (9)	0.0054 (12)	0.0066 (11)
C17	0.0433 (13)	0.0315 (13)	0.0368 (14)	0.0003 (9)	−0.0003 (12)	0.0008 (10)
C18	0.0474 (13)	0.0270 (11)	0.0342 (13)	0.0023 (9)	−0.0053 (12)	0.0045 (10)
C19	0.0717 (17)	0.0542 (17)	0.0429 (17)	0.0089 (14)	−0.0183 (15)	−0.0053 (14)

Geometric parameters (Å, º)

O1—C16	1.358 (3)	C7—C8	1.376 (4)
O1—H1	0.8200	C7—H7	0.9300
O2—C17	1.367 (3)	C8—C9	1.380 (3)
O2—C19	1.424 (3)	C8—H8	0.9300
N1—C5	1.329 (3)	C9—C10	1.379 (4)
N1—C4	1.342 (3)	C9—H9	0.9300
N2—C6	1.339 (3)	C10—C11	1.477 (3)
N2—C7	1.348 (4)	C12—C13	1.459 (3)
N3—C11	1.294 (3)	C12—H12	0.9300
N3—N4	1.405 (3)	C13—C14	1.389 (3)
N4—C12	1.283 (3)	C13—C18	1.402 (3)
C1—C2	1.387 (3)	C14—C15	1.398 (3)
C1—C5	1.409 (3)	C14—H14	0.9300
C1—C11	1.484 (3)	C15—C16	1.373 (4)
C2—C3	1.375 (4)	C15—H15	0.9300
C2—H2	0.9300	C16—C17	1.415 (3)
C3—C4	1.387 (4)	C17—C18	1.374 (3)
C3—H3	0.9300	C18—H18	0.9300
C4—H4	0.9300	C19—H19A	0.9600
C5—C6	1.477 (3)	C19—H19B	0.9600
C6—C10	1.399 (3)	C19—H19C	0.9600
C16—O1—H1	109.5	C9—C10—C6	120.0 (2)
C17—O2—C19	116.2 (2)	C9—C10—C11	131.5 (2)
C5—N1—C4	114.6 (2)	C6—C10—C11	108.6 (2)
C6—N2—C7	114.6 (2)	N3—C11—C10	120.8 (2)
C11—N3—N4	112.5 (2)	N3—C11—C1	133.1 (2)
C12—N4—N3	112.1 (2)	C10—C11—C1	106.2 (2)
C2—C1—C5	118.0 (2)	N4—C12—C13	120.1 (2)
C2—C1—C11	133.7 (2)	N4—C12—H12	119.9
C5—C1—C11	108.3 (2)	C13—C12—H12	119.9
C3—C2—C1	117.0 (2)	C14—C13—C18	119.5 (2)
C3—C2—H2	121.5	C14—C13—C12	120.1 (2)
C1—C2—H2	121.5	C18—C13—C12	120.5 (2)
C2—C3—C4	120.5 (3)	C13—C14—C15	119.1 (2)
C2—C3—H3	119.7	C13—C14—H14	120.4
C4—C3—H3	119.7	C15—C14—H14	120.4
N1—C4—C3	124.1 (3)	C16—C15—C14	121.6 (2)
N1—C4—H4	117.9	C16—C15—H15	119.2
C3—C4—H4	117.9	C14—C15—H15	119.2
N1—C5—C1	125.6 (2)	O1—C16—C15	123.6 (2)
N1—C5—C6	126.2 (2)	O1—C16—C17	117.2 (2)
C1—C5—C6	108.2 (2)	C15—C16—C17	119.2 (2)
N2—C6—C10	123.7 (2)	O2—C17—C18	124.4 (2)
N2—C6—C5	127.5 (2)	O2—C17—C16	116.2 (2)
C10—C6—C5	108.81 (18)	C18—C17—C16	119.4 (2)
N2—C7—C8	125.5 (2)	C17—C18—C13	121.2 (2)
N2—C7—H7	117.2	C17—C18—H18	119.4
C8—C7—H7	117.2	C13—C18—H18	119.4
C7—C8—C9	119.1 (3)	O2—C19—H19A	109.5
C7—C8—H8	120.4	O2—C19—H19B	109.5
C9—C8—H8	120.4	H19A—C19—H19B	109.5
C10—C9—C8	117.1 (3)	O2—C19—H19C	109.5
C10—C9—H9	121.5	H19A—C19—H19C	109.5
C8—C9—H9	121.5	H19B—C19—H19C	109.5
C11—N3—N4—C12	177.7 (2)	N4—N3—C11—C1	−2.6 (4)
C5—C1—C2—C3	−1.5 (3)	C9—C10—C11—N3	−2.8 (4)
C11—C1—C2—C3	179.8 (3)	C6—C10—C11—N3	178.7 (2)
C1—C2—C3—C4	0.9 (4)	C9—C10—C11—C1	177.5 (3)
C5—N1—C4—C3	0.1 (4)	C6—C10—C11—C1	−1.0 (3)
C2—C3—C4—N1	−0.1 (4)	C2—C1—C11—N3	−0.1 (5)
C4—N1—C5—C1	−0.8 (4)	C5—C1—C11—N3	−178.9 (2)
C4—N1—C5—C6	−179.8 (2)	C2—C1—C11—C10	179.5 (3)
C2—C1—C5—N1	1.6 (3)	C5—C1—C11—C10	0.7 (2)
C11—C1—C5—N1	−179.4 (2)	N3—N4—C12—C13	178.0 (2)
C2—C1—C5—C6	−179.3 (2)	N4—C12—C13—C14	179.0 (2)
C11—C1—C5—C6	−0.2 (2)	N4—C12—C13—C18	−0.9 (4)
C7—N2—C6—C10	−1.1 (4)	C18—C13—C14—C15	−0.8 (4)
C7—N2—C6—C5	178.1 (2)	C12—C13—C14—C15	179.4 (2)
N1—C5—C6—N2	−0.5 (4)	C13—C14—C15—C16	−0.4 (4)
C1—C5—C6—N2	−179.7 (2)	C14—C15—C16—O1	−179.0 (2)
N1—C5—C6—C10	178.8 (2)	C14—C15—C16—C17	1.7 (4)
C1—C5—C6—C10	−0.4 (3)	C19—O2—C17—C18	10.0 (4)
C6—N2—C7—C8	−0.2 (4)	C19—O2—C17—C16	−170.9 (2)
N2—C7—C8—C9	1.0 (5)	O1—C16—C17—O2	−0.3 (3)
C7—C8—C9—C10	−0.6 (4)	C15—C16—C17—O2	179.1 (2)
C8—C9—C10—C6	−0.5 (4)	O1—C16—C17—C18	178.9 (2)
C8—C9—C10—C11	−178.9 (2)	C15—C16—C17—C18	−1.7 (4)
N2—C6—C10—C9	1.5 (4)	O2—C17—C18—C13	179.6 (2)
C5—C6—C10—C9	−177.8 (2)	C16—C17—C18—C13	0.5 (3)
N2—C6—C10—C11	−179.8 (2)	C14—C13—C18—C17	0.7 (4)
C5—C6—C10—C11	0.8 (3)	C12—C13—C18—C17	−179.4 (2)
N4—N3—C11—C10	177.8 (2)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1A···N2^i	0.82	2.11	2.844 (3)	150

Symmetry code: (i) −x+3/2, y−1/2, z+1/2.