N-(3-Chloro­phenyl)-2-hydroxy-1-naphthald­imine at 200 K

The title compound, C₁₇H₁₂ClNO, (I), exists as the enol–imino tautomer [Csp²—O 1.333 (2) Å] in the solid state at 200 K, while NMR spectroscopy reveals the keto­amino form in di­methyl sulfoxide solution. The orientation of the Csp²—O (for the OH tautomer) and the Csp²=O bond (for the NH tautomer) towards the N-3-chloro­phenyl substituent shows that both tautomers are E isomers with respect to the imino N=C bond. The solid-state OH tautomer is benzeno­id, forming the very short resonance-assisted O—H...N intramolecular hydrogen bond [N...O 2.537 (2) Å]. The mol­ecules are assembled using only van der Waals contacts. The packing of the mol­ecules within the unit cell implies π–π interactions of adjacent naphthalene and phenyl rings, respectively. The energetically more favourable non-planar geometry [the dihedral angle between the naphthalene and 3-chloro­phenyl rings is 17.2 (1)°] is in accordance with the absence of intermolecular hydrogen bonding that could compensate the formation of a less energetically favourable planar mol­ecule.

Key indicators

• Single-crystal X-ray study
• T = 200 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.041
• wR factor = 0.109
• Data-to-parameter ratio = 16.0

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


 Alert Level C:



CELLV_02  Alert C The supplied cell volume s.u. differs from that
          calculated from the cell parameter s.u.'s by > 2
          Calculated cell volume su =      12.51
          Cell volume su given      =      10.00


 0 Alert Level A = Potentially serious problem

 0 Alert Level B = Potential problem

 1 Alert Level C = Please check

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S1. Comment

The design and synthesis of organic compounds with desired physical properties, by methods of crystal engineering, based on molecular recognition and self-organization, are under development for many applications (non-linear optics, organic superconductors, optical sensors, etc.) (Feringa et al., 1993). The Schiff bases derived from o-hydroxy aromatic aldehydes with various alkyl or aryl N-substituents [Ar—C═ N—Ar(R)] exhibit interesting photo- and thermochromic features. The salicylaldimine Schiff bases have been investigated more than naphthaldimines over the last 40 years (Cohen & Schmidt, 1962; Carles et al., 1987; Inabe, 1991; Rontoyianni et al., 1994; Hadjoudis, 1994, 1995; Ogawa & Fujiwara, 1999; Ogawa, 1999, 2000; Ogawa et al., 2000, 2001; Pizzala et al., 2000). Chromic behaviour is strongly related to the tautomerization between the O—H···N═C—C═C (enolimino) and —C═ O···H—N—C═C— (ketoamino) tautomeric forms. The tautomerization induced by intramolecular proton transfer is accompanied by a π-electron configurational change in the central heterodienic moiety of the molecule (the two tautomers have different π-electron distributions). The presence of the particular tautomer in the crystal is the synergetic function of the type of parent o-hydroxy aromatic aldehyde and the type of N-substituent (i.e. the type of amine used), implying that there is no simple correlation between the type of aldehyde and the molecular structure (i.e. tautomer) of the derived Schiff base. In other words, the electron withdrawing or donating ability of substituents and their position on the aromatic core, as well as hydrogen bonding donor–acceptor properties, can stabilize one or other tautomer in the crystal.

Photochromy and thermochromy are mutually exclusive properties in crystalline Schiff bases. The existence of one particular Schiff base compound in the NH form in one crystal and the OH form in another leads to polymorphism of Schiff bases, establishing that the crystal structure is responsible for the chromic behaviour of the Schiff base.

It has been established, thus far, that Schiff bases of the naphthaldimine type can exist in both the NH and OH forms. The NH form (for those derived only from primary amines) has been established by X-ray single-crystal diffraction in the structures of N-n-propyl-2-oxo-1-naphthylidenemethylamine (Kaitner & Pavlović, 1996), N-(α-naphthyl)- and N-(β-naphthyl)-2-oxo-1-naphthaldimines (Gavranić et al., 1996), an N-4-methyl-2-pyridyl derivative (Elerman et al., 1998), N-(2-hydroxyethyl)-2-oxo-1-naphthaldimine (Kaitner & Pavlović, 1999), N-(3-carboxy-phenyl)-2-hydroxy-1-naphthaldimine (Pavlović & Matijević-Sosa, 2000) and 1-[N-(2-pyridyl)aminomethylidene]-2-naphthalenone (Hökelek et al., 2000), while the OH tautomer (for those derived only from primary amines) has been found in the structures of N-o-tolyl-2-hydroxy-1-naphthaldimine (Kaitner et al., 1998), N-(2-bromo-4-methylphenyl)naphthaldimine (Elmali, Elerman & Kendi, 1998), N-(3,5-dichlorophenyl)naphthaldimine (Elmali, Elerman, Svoboda & Fuess, 1998), 1-[(3-nitrophenylimino)methyl]-2-naphthol (Yeap et al., 1998) and N-(2-aminophenyl)naphthaldimine (Govindasamy et al., 1999). The dynamic disorder of the hydrogen position between the oxygen and the nitrogen site, as in the structure of N-(2-hydroxy-1-naphthylmethylene)-1-pyrenamine (Inabe et al., 1994), reveals the possibility that both tautomeric forms are present in the crystal [N···O hydrogen bond distance is 2.530 (6) and 2.551 (5) Å at 295 and 120 K, respectively].

It should be stressed that there is no simple relation between molecular conformation and the type of tautomer present in the crystalline state. In other words, the previously established well known fact that the NH tautomers are planar and the OH tautomers are non-planar is no longer accepted. There are ketoamino (NH) naphthaldimines of the Ar—C═N–R type with non-planar N-alkyl substituents such as N-n-propyl-2-oxo-1-naphthylidenemethylamine (Kaitner & Pavlović, 1996) and N-(2-hydroxyethyl)-2-oxo-1-naphthaldimine (Kaitner & Pavlović, 1999), while in the ketoamino Ar—C═N—Ar naphthaldimines, the naphthaldiminate moiety and the N-aryl substituent are inclined to each other at angles in the range 4.41 (7) (Pavlović & Matijević-Sosa, 2000) to 6.95 (5)° (Hökelek et al., 2000). On the other hand, enolimino (OH) naphthaldimines with N-aryl substituents are in planar (Elmali, Elerman, Svoboda & Fuess, 1998; Yeap et al., 1998), as well as in non-planar conformation in crystals (Elmali, Elerman & Kendi, 1998; Govindasamy et al., 1999; Kaitner et al., 1998). Obviously, the planarity and/or non-planarity is not an exclusive feature of the OH or NH tautomers.

The Csp²—O and N═C bonds of the central part of the molecule are the most affected by the π-electron distribution within the Schiff base and thus are the most sensitive molecular geometry fragments in the determination of the ketoamino–enolimino tautomeric equilibrium shift. The O—C bond distances observed in ketoamino tautomers cited above are 1.274 (4)–1.302 (3) Å, and those in enol tautomers 1.320 (3)–1.323 (3) Å. The imino N═C bond distances observed in the crystals of NH tautomers are 1.294 (5)–1.345 (4) Å, longer than those in OH tautomers, 1.290 (3)–1.291 (4) Å. The C2—O and N═C11 bond distance values in the title Schiff base are 1.333 (2) and 1.295 (2) Å, respectively. The H atom belonging to the oxygen site was found in an electron-density map at a distance O—H1O of 1.01 (3) Å; together with the C2—O—H1O bond angle value of 105 (2)°, this confirms the sp³ hybridization of the O atom. The single Cl—C14 bond distance value is normal, 1.745 (2) Å (Allen et al., 1987). The bond distances within the phenyl and naphthyl rings are normal (Allen et al., 1987). The torsion angle around the single N—C12 bond is 13.7 (2)°, revealing molecular non-planarity, which is accompanied by involvment of the N lone electron pair in resonance with the π-electron system of the N-phenyl ring. The only known crystal structure of naphthaldimine with the N-group substituted by chlorine is the nearly planar structure of N-(3,5-dichlorophenyl)naphthaldimine (Elmali, Elerman, Svoboda & Fuess, 1998), with an O—H···N intramolecular hydrogen bond of 2.570 (3) Å.

The hydrogen-bond distances of the above-mentioned naphthaldimine Schiff bases are in the range 2.503 (3)–2.570 (3) Å for OH tautomers and 2.531 (3)–2.578 (2) Å for NH tautomers and they belong to the RAHB (resonance-assisted hydrogen bond) type of hydrogen bond (Bertolasi et al., 1993; Dziembowska, 1994, 1998; Bertolasi et al., 1999; Krygowski et al., 1999; Gilli et al., 2000). The π-electron delocalization is spread out over the central part of the molecule formed by the pseudoaromatic six-membered chelate ring. The hydrogen bond length in the title Schiff base is among the shorter ones in naphthaldimines [O···N 2.537 (2) Å, O—H 1.01 (3) Å, H···N 1.60 (3) Å and O—H···N angle 152 (3)°)]. The IR spectral data confirms the enol tautomer in the solid state (Yuzawa et al., 1993). ¹H and ¹³C NMR spectra reveal the ketoamino form of the Schiff base in dimethyl sulfoxide solution. The syn orientation of meta-Cl towards the C-α proton was deduced from the NOE contacts in ¹H spectra. Variable temperature measurements showed that the large downfield chemical shift of NH arises from intramolecular hydrogen bonding.

S2. Experimental

The title compound was prepared by adding 3-chloroaniline (127 mg, 1 mmol) to a solution of 2-hydroxynaphthaldehyde (172 mg, 1 mmol) in methanol (approximately 10 ml). After stirring the reaction mixture for 3 h at room temperature, a yellow precipitate was formed. The crude yellow product, obtained from the reaction mixture by cooling, was separated under vacuum and washed with water (196 mg, yield 70%; m.p. 384–386 K; literature m. p. 389–390 K; Beilstein 12EI302). Recrystallization from toluene by slow evaporation gave single crystals of good diffraction quality. IR spectral data were recorded with a Paragon 500 F T—IR Perkin-Elmer spectrophotometer. IR (KBr, cm^-1): 1619 and 1569 (C═N), 1318 (Csp²—O). One- and two dimensional NMR spectra (COSY, NOESY, HETCOR and HMBC) were recorded with a Gemini 300 and Unity Inova 300 Varian spectrometers. The samples were dissolved in dimethyl sulfoxide and measured at 293 K in 5 mm NMR tubes. The concentration was 7 mg ml^-1 for ¹H and 15 mg ml^-1 for ¹³C measurements. Chemical shifts are referred to TMS. ¹H NMR shifts (p.p.m.): NH 15.48 (d), Hα 9.69 (d), H8 8.55 (d), H4 7.96 (d), H2' 7.86 (s), H5 7.81 (d), H7 7.56 (t), H5' 7.50 (t), H6' 7.54 (d), H4' 7.36 (d), H6 7.37 (t) and H3 7.04 (d). ¹³C NMR shifts (p.p.m.): C═0 169.58 (s), Cα 157.16 (d), C1' 146.12 (s), C4 137.12 (d), C3' 134.21 (s), C9 133.12 (s), C5' 131.11 (d), C5 129.04 (d), C7 128.18 (d), C10 126.89 (s9, C4' 126.19 (d), C6 123.73 (d), C3 121.71 (d), C8 120.74 (d), C6' 120.20 (d), C2' 120.08 (d), C1 108.86 (s). The multiplicity of signals is denoted within parentheses: s = singlet, d = doublet and t = triplet. The atom-numbering scheme is shown in the Scheme.

S3. Refinement

Diffraction data were collected on a Nonius KappaCCD diffractometer (capillary optics) at 200 K. 385 frames were collected at the crystal-detector distance of 35 mm, 10 s/°, 8 sets of ω scans, 1° per frame. All H atoms were included in calculated positions as riding atoms, with SHELXL97 (Sheldrick, 1997) default parameters, except for atom H1O which was found in an electron-density Fourier map at a distance O—H1O of 1.01 (3) Å and refined freely.

Computing details

Data collection: DENZO and COLLECT (Otwinowski & Minor, 1997); cell refinement: DENZO and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON98 (Spek, 1998); software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. A perspective view of the molecule of (I), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. The intramolecular O—H···N hydrogen bond is indicated by a dashed line.
	Fig. 2. The crystal structure of (I), showing the herring bone type of molecular packing. The π–π interactions appear along the short b axis.

1-[(3-chlorophenylimino)methyl]-2-naphthol

Crystal data

C17H12ClNO	F(000) = 1168
Mr = 281.73	Dx = 1.411 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 30.706 (1) Å	Cell parameters from 2100 reflections
b = 4.7860 (1) Å	θ = 1–27.5°
c = 18.9937 (5) Å	µ = 0.28 mm^−1
β = 108.133 (1)°	T = 200 K
V = 2652.69 (10) Å^3	Prism, pale yellow
Z = 8	0.15 × 0.13 × 0.08 mm

Data collection

Nonius KappaCCD area-detector diffractometer	2387 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.020
Graphite monochromator	θmax = 27.5°, θmin = 4.2°
ω scans	h = −39→39
4881 measured reflections	k = −4→6
2954 independent reflections	l = −24→24

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.041	Hydrogen site location: geom and difmap
wR(F^2) = 0.109	H atoms treated by a mixture of independent and constrained refinement
S = 1.04	w = 1/[σ^2(Fo^2) + (0.0456P)^2 + 2.5286P] where P = (Fo^2 + 2Fc^2)/3
2954 reflections	(Δ/σ)max < 0.001
185 parameters	Δρmax = 0.27 e Å^−3
0 restraints	Δρmin = −0.33 e Å^−3

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

	x	y	z	Uiso*/Ueq
Cl	0.051305 (15)	0.00834 (11)	0.33280 (3)	0.04654 (16)
N	0.16582 (4)	−0.6462 (3)	0.51760 (7)	0.0291 (3)
O	0.22618 (4)	−0.8836 (3)	0.62324 (7)	0.0372 (3)
H1O	0.2107 (10)	−0.761 (6)	0.5793 (16)	0.081 (8)*
C1	0.14610 (5)	−0.9921 (3)	0.59314 (8)	0.0256 (3)
C2	0.19226 (5)	−1.0268 (3)	0.63633 (8)	0.0294 (3)
C3	0.20416 (6)	−1.2183 (4)	0.69631 (9)	0.0337 (4)
H3	0.2347	−1.2382	0.7249	0.040*
C4	0.17152 (6)	−1.3719 (4)	0.71218 (8)	0.0326 (4)
H4	0.1801	−1.4956	0.7519	0.039*
C5	0.12425 (5)	−1.3499 (3)	0.66975 (8)	0.0292 (3)
C6	0.09075 (6)	−1.5128 (4)	0.68704 (9)	0.0374 (4)
H6	0.0995	−1.6348	0.7271	0.045*
C7	0.04554 (6)	−1.4947 (4)	0.64600 (11)	0.0420 (4)
H7	0.0237	−1.6025	0.6582	0.050*
C8	0.03253 (6)	−1.3134 (4)	0.58588 (10)	0.0401 (4)
H8	0.0018	−1.3028	0.5575	0.048*
C9	0.06425 (6)	−1.1492 (4)	0.56758 (9)	0.0337 (4)
H9	0.0546	−1.0296	0.5271	0.040*
C10	0.11128 (5)	−1.1595 (3)	0.60935 (8)	0.0267 (3)
C11	0.13468 (5)	−0.7905 (3)	0.53409 (8)	0.0272 (3)
H11	0.1041	−0.7629	0.5070	0.033*
C12	0.15531 (5)	−0.4443 (3)	0.46049 (8)	0.0268 (3)
C13	0.11152 (5)	−0.3371 (3)	0.42633 (8)	0.0282 (3)
H13	0.0865	−0.4036	0.4391	0.034*
C14	0.10589 (5)	−0.1312 (4)	0.37348 (8)	0.0309 (3)
C15	0.14197 (6)	−0.0268 (4)	0.35237 (8)	0.0344 (4)
H15	0.1373	0.1134	0.3169	0.041*
C16	0.18526 (6)	−0.1372 (4)	0.38557 (9)	0.0367 (4)
H16	0.2100	−0.0721	0.3718	0.044*
C17	0.19215 (5)	−0.3441 (4)	0.43925 (9)	0.0330 (4)
H17	0.2214	−0.4162	0.4611	0.040*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl	0.0363 (2)	0.0489 (3)	0.0485 (3)	0.0010 (2)	0.00465 (18)	0.0167 (2)
N	0.0303 (6)	0.0289 (7)	0.0287 (6)	−0.0001 (5)	0.0099 (5)	−0.0025 (5)
O	0.0248 (5)	0.0429 (7)	0.0415 (6)	0.0008 (5)	0.0069 (5)	0.0028 (6)
C1	0.0276 (7)	0.0258 (7)	0.0225 (6)	0.0021 (6)	0.0068 (5)	−0.0033 (6)
C2	0.0279 (7)	0.0300 (8)	0.0292 (7)	0.0023 (6)	0.0073 (6)	−0.0053 (6)
C3	0.0302 (8)	0.0365 (9)	0.0290 (7)	0.0078 (7)	0.0018 (6)	−0.0015 (7)
C4	0.0380 (8)	0.0316 (8)	0.0255 (7)	0.0084 (7)	0.0063 (6)	0.0017 (6)
C5	0.0349 (8)	0.0286 (8)	0.0246 (7)	0.0039 (6)	0.0099 (6)	−0.0021 (6)
C6	0.0459 (9)	0.0352 (9)	0.0326 (8)	0.0013 (8)	0.0144 (7)	0.0056 (7)
C7	0.0398 (9)	0.0408 (10)	0.0487 (10)	−0.0055 (8)	0.0188 (8)	0.0032 (8)
C8	0.0292 (8)	0.0447 (10)	0.0446 (9)	−0.0015 (8)	0.0088 (7)	0.0016 (8)
C9	0.0306 (8)	0.0354 (9)	0.0337 (8)	0.0023 (7)	0.0081 (6)	0.0042 (7)
C10	0.0288 (7)	0.0262 (7)	0.0253 (7)	0.0031 (6)	0.0088 (6)	−0.0040 (6)
C11	0.0277 (7)	0.0273 (8)	0.0253 (7)	0.0008 (6)	0.0065 (6)	−0.0035 (6)
C12	0.0301 (7)	0.0261 (7)	0.0245 (7)	−0.0034 (6)	0.0092 (6)	−0.0057 (6)
C13	0.0297 (7)	0.0284 (8)	0.0275 (7)	−0.0051 (6)	0.0104 (6)	−0.0027 (6)
C14	0.0331 (8)	0.0317 (8)	0.0259 (7)	−0.0051 (7)	0.0063 (6)	−0.0035 (6)
C15	0.0441 (9)	0.0333 (9)	0.0262 (7)	−0.0100 (7)	0.0118 (7)	−0.0020 (6)
C16	0.0386 (9)	0.0416 (10)	0.0347 (8)	−0.0131 (8)	0.0183 (7)	−0.0060 (7)
C17	0.0293 (7)	0.0368 (9)	0.0343 (8)	−0.0052 (7)	0.0116 (6)	−0.0061 (7)

Geometric parameters (Å, º)

Cl—C14	1.7453 (17)	C7—C8	1.390 (3)
N—C11	1.294 (2)	C7—H7	0.9300
N—C12	1.413 (2)	C8—C9	1.377 (2)
O—C2	1.3330 (19)	C8—H8	0.9300
O—H1O	1.01 (3)	C9—C10	1.416 (2)
C1—C2	1.409 (2)	C9—H9	0.9300
C1—C11	1.438 (2)	C11—H11	0.9300
C1—C10	1.444 (2)	C12—C13	1.396 (2)
C2—C3	1.419 (2)	C12—C17	1.399 (2)
C3—C4	1.351 (2)	C13—C14	1.379 (2)
C3—H3	0.9300	C13—H13	0.9300
C4—C5	1.428 (2)	C14—C15	1.384 (2)
C4—H4	0.9300	C15—C16	1.386 (3)
C5—C6	1.409 (2)	C15—H15	0.9300
C5—C10	1.422 (2)	C16—C17	1.389 (3)
C6—C7	1.367 (3)	C16—H16	0.9300
C6—H6	0.9300	C17—H17	0.9300
C11—N—C12	122.77 (13)	C8—C9—H9	119.4
C2—O—H1O	104.9 (16)	C10—C9—H9	119.4
C2—C1—C11	119.34 (14)	C9—C10—C5	117.09 (14)
C2—C1—C10	119.22 (14)	C9—C10—C1	123.73 (14)
C11—C1—C10	121.44 (13)	C5—C10—C1	119.17 (13)
O—C2—C1	122.26 (14)	N—C11—C1	121.84 (14)
O—C2—C3	117.44 (14)	N—C11—H11	119.1
C1—C2—C3	120.30 (14)	C1—C11—H11	119.1
C4—C3—C2	120.49 (15)	C13—C12—C17	119.22 (14)
C4—C3—H3	119.8	C13—C12—N	124.39 (13)
C2—C3—H3	119.8	C17—C12—N	116.37 (14)
C3—C4—C5	121.91 (15)	C14—C13—C12	119.05 (14)
C3—C4—H4	119.0	C14—C13—H13	120.5
C5—C4—H4	119.0	C12—C13—H13	120.5
C6—C5—C10	120.08 (14)	C13—C14—C15	122.59 (15)
C6—C5—C4	121.03 (14)	C13—C14—Cl	118.78 (12)
C10—C5—C4	118.89 (14)	C15—C14—Cl	118.62 (13)
C7—C6—C5	121.18 (16)	C14—C15—C16	118.14 (16)
C7—C6—H6	119.4	C14—C15—H15	120.9
C5—C6—H6	119.4	C16—C15—H15	120.9
C6—C7—C8	119.28 (16)	C15—C16—C17	120.71 (15)
C6—C7—H7	120.4	C15—C16—H16	119.6
C8—C7—H7	120.4	C17—C16—H16	119.6
C9—C8—C7	121.22 (16)	C16—C17—C12	120.27 (15)
C9—C8—H8	119.4	C16—C17—H17	119.9
C7—C8—H8	119.4	C12—C17—H17	119.9
C8—C9—C10	121.12 (15)