1-[(2-Anilinoeth­yl)iminiometh­yl]-2-naph­thol­ate

The title Schiff base compound, C₁₉H₁₈N₂O, was prepared by the reaction of equimolar quanti­ties of 2-hydr­oxy-1-naphthaldehyde with N-phenyl­ethane-1,2-diamine in a methanol solution. The mol­ecule adopts a zwitterionic conformation with the naphthyl OH group deprotonated and the imine N atom protonated. An intra­molecular N—H...O hydrogen bond forms between them. The dihedral angle between the benzene ring and the naphthyl system is 86.9 (2)°. In the crystal structure, mol­ecules are linked through inter­molecular N—H...O hydrogen bonds, forming chains running along the b axis.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.005 Å
• R factor = 0.038
• wR factor = 0.105
• Data-to-parameter ratio = 8.7

checkCIF/PLATON results

No syntax errors found



Alert level C
SHFSU01_ALERT_2_C  Test not performed. _refine_ls_shift/su_max and
            _refine_ls_shift/esd_max not present.
            Absolute value of the parameter shift to su ratio given   0.001
PLAT340_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang ...          5

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           27.49
           From the CIF: _reflns_number_total               1753
           Count of symmetry unique reflns         1782
           Completeness (_total/calc)             98.37%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured         0
           Fraction of Friedel pairs measured     0.000
           Are heavy atom types Z>Si present         no
PLAT333_ALERT_2_G Check Large Av C6-Ring C-C Dist. C1     -C10           1.42 Ang.
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          3
PLAT066_ALERT_1_G Predicted and Reported Transmissions Identical .          ?

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   2 ALERT level C = Check and explain
   4 ALERT level G = General alerts; check

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   2 ALERT type 2 Indicator that the structure model may be wrong or deficient
   2 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

Schiff base compounds are an important class of materials used in the pharmaceutical and medicinal fields (Dao et al., 2000; Sriram et al., 2006; Karthikeyan et al., 2006). They are also used as versatile ligands in coordination chemistry (Ali et al., 2008; Kargar et al., 2009; Yeap et al., 2009). Recently, the crystal structures of several Schiff base compounds have been reported (Fun et al., 2009; Nadeem et al., 2009; Eltayeb et al., 2008). In this paper, the new Schiff base title compound, (I), Fig. 1, is reported.

In (I), the H atom of the phenol group is transferred to the imine N atom, forming an intramolecular N–H···O hydrogen bond (Table 1). The dihedral angle between the benzene ring and the naphthyl ring is 86.9 (2)°. All the bond lengths are within normal values (Allen et al., 1987). In the crystal structure of the compound, molecules are linked through intermolecular N–H···O hydrogen bonds (Table 1), forming chains running along the b axis (Fig. 2).

Related literature

For the pharmaceutical and medicinal activity of Schiff bases, see: Dao et al. (2000); Sriram et al. (2006); Karthikeyan et al. (2006). For Schiff base coordination chemistry, see: Ali et al. (2008); Kargar et al. (2009); Yeap et al. (2009). For related structures, see: Fun et al. (2009); Nadeem et al. (2009); Eltayeb et al. (2008). For reference structural data, see: Allen et al. (1987).

S2. Experimental

2-Hydroxy-1-naphthylaldehyde (0.1 mmol, 17.2 mg) and N-phenylethane-1,2-diamine (0.1 mmol, 13.6 mg) were refluxed in a 30 ml methanol solution for 30 min to give a clear orange solution. Yellow block-shaped single crystals of the compound were formed by slow evaporation of the solvent over several days at room temperature.

S3. Refinement

In the absence of significant anomalous dispersion effects, 1421 Freidel pairs were merged. H1 was located from a difference Fourier map and refined isotropically, with the N–H distance restrained to 0.90 (1)Å, and with U_iso restrained to 0.08Ų. Other H atoms were constrained to ideal geometries, with d(C–H) = 0.93–0.97Å, d(N–H) = 0.86Å, and with U_iso(H) = 1.2U_eq(C,N).

Computing details

Data collection: SMART (Bruker, 2002); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT (Bruker, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures

	Fig. 1. The molecular structure of (I) with 30% probability ellipsoids. The intramolecular N–H···O hydrogen bond is shown as a dashed line.
	Fig. 2. Molecular packing of (I) with hydrogen bonds drawn as dashed lines.

1-[(2-Anilinoethyl)iminiomethyl]-2-naphtholate

Crystal data

C19H18N2O	F(000) = 616
Mr = 290.35	Dx = 1.237 Mg m^−3
Monoclinic, Cc	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: C -2yc	Cell parameters from 1258 reflections
a = 27.511 (3) Å	θ = 2.5–24.5°
b = 6.845 (2) Å	µ = 0.08 mm^−1
c = 8.543 (2) Å	T = 298 K
β = 104.263 (2)°	Block, yellow
V = 1559.2 (6) Å^3	0.23 × 0.21 × 0.18 mm
Z = 4

Data collection

Bruker SMART CCD area-detector diffractometer	1753 independent reflections
Radiation source: fine-focus sealed tube	1312 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.021
ω scans	θmax = 27.5°, θmin = 3.1°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −31→35
Tmin = 0.982, Tmax = 0.986	k = −6→8
4485 measured reflections	l = −11→11

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)] = 0.038	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.105	H atoms treated by a mixture of independent and constrained refinement
S = 1.06	w = 1/[σ^2(Fo^2) + (0.0531P)^2 + 0.1092P] where P = (Fo^2 + 2Fc^2)/3
1753 reflections	(Δ/σ)max < 0.001
202 parameters	Δρmax = 0.18 e Å^−3
3 restraints	Δρmin = −0.18 e Å^−3

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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	0.52924 (7)	0.9086 (3)	0.4162 (2)	0.0576 (5)
N1	0.53391 (8)	0.5581 (3)	0.5306 (3)	0.0497 (5)
N2	0.46277 (8)	0.2671 (3)	0.3271 (3)	0.0522 (6)
H2	0.4912	0.2202	0.3207	0.063*
C1	0.60256 (9)	0.7135 (4)	0.4543 (3)	0.0465 (6)
C2	0.57425 (10)	0.8886 (4)	0.4038 (3)	0.0491 (6)
C3	0.59731 (11)	1.0404 (4)	0.3330 (4)	0.0608 (7)
H3	0.5793	1.1537	0.2974	0.073*
C4	0.64475 (12)	1.0231 (5)	0.3167 (4)	0.0658 (8)
H4	0.6583	1.1247	0.2689	0.079*
C5	0.67481 (11)	0.8544 (5)	0.3702 (3)	0.0583 (7)
C6	0.72446 (13)	0.8429 (6)	0.3537 (5)	0.0791 (10)
H6	0.7374	0.9433	0.3027	0.095*
C7	0.75394 (13)	0.6840 (7)	0.4128 (5)	0.0908 (12)
H7	0.7868	0.6775	0.4031	0.109*
C8	0.73446 (14)	0.5358 (7)	0.4859 (6)	0.0953 (13)
H8	0.7546	0.4294	0.5269	0.114*
C9	0.68608 (12)	0.5403 (5)	0.5000 (5)	0.0748 (9)
H9	0.6738	0.4360	0.5487	0.090*
C10	0.65441 (10)	0.6995 (4)	0.4422 (3)	0.0541 (7)
C11	0.57962 (10)	0.5575 (4)	0.5134 (3)	0.0490 (6)
H11	0.5985	0.4445	0.5427	0.059*
C12	0.50873 (11)	0.3947 (4)	0.5875 (4)	0.0568 (7)
H12A	0.5046	0.4237	0.6945	0.068*
H12B	0.5293	0.2784	0.5948	0.068*
C13	0.45822 (10)	0.3570 (4)	0.4749 (4)	0.0540 (7)
H13A	0.4389	0.2724	0.5278	0.065*
H13B	0.4403	0.4796	0.4504	0.065*
C14	0.42170 (10)	0.2552 (4)	0.1944 (3)	0.0477 (6)
C15	0.42493 (12)	0.1449 (4)	0.0608 (4)	0.0590 (7)
H15	0.4542	0.0759	0.0627	0.071*
C16	0.38583 (14)	0.1359 (4)	−0.0735 (4)	0.0689 (9)
H16	0.3890	0.0605	−0.1609	0.083*
C17	0.34208 (13)	0.2356 (5)	−0.0821 (5)	0.0732 (9)
H17	0.3157	0.2291	−0.1742	0.088*
C18	0.33809 (12)	0.3459 (5)	0.0492 (4)	0.0687 (8)
H18	0.3088	0.4154	0.0454	0.082*
C19	0.37702 (11)	0.3545 (4)	0.1862 (4)	0.0579 (7)
H19	0.3734	0.4276	0.2743	0.070*
H1	0.5170 (12)	0.671 (3)	0.501 (4)	0.080*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0519 (11)	0.0450 (10)	0.0754 (13)	0.0099 (8)	0.0146 (9)	0.0058 (9)
N1	0.0534 (14)	0.0385 (12)	0.0542 (13)	0.0029 (9)	0.0075 (11)	0.0009 (9)
N2	0.0450 (12)	0.0432 (12)	0.0711 (15)	0.0038 (9)	0.0196 (11)	−0.0043 (10)
C1	0.0464 (14)	0.0426 (13)	0.0468 (13)	0.0018 (11)	0.0048 (11)	−0.0035 (11)
C2	0.0530 (16)	0.0412 (14)	0.0482 (15)	0.0029 (11)	0.0032 (12)	−0.0041 (11)
C3	0.0627 (18)	0.0502 (17)	0.0656 (19)	0.0018 (13)	0.0084 (15)	0.0088 (14)
C4	0.068 (2)	0.0579 (18)	0.0687 (19)	−0.0112 (14)	0.0112 (16)	0.0064 (15)
C5	0.0512 (15)	0.064 (2)	0.0569 (16)	−0.0055 (13)	0.0081 (13)	−0.0087 (13)
C6	0.058 (2)	0.092 (3)	0.088 (2)	−0.0136 (18)	0.0210 (18)	−0.009 (2)
C7	0.054 (2)	0.107 (3)	0.112 (3)	0.005 (2)	0.021 (2)	−0.014 (3)
C8	0.063 (2)	0.087 (3)	0.136 (4)	0.025 (2)	0.024 (2)	0.004 (3)
C9	0.0580 (19)	0.067 (2)	0.098 (2)	0.0130 (15)	0.0163 (18)	0.0022 (19)
C10	0.0495 (15)	0.0532 (16)	0.0548 (16)	0.0020 (12)	0.0039 (12)	−0.0087 (12)
C11	0.0533 (16)	0.0392 (14)	0.0500 (14)	0.0088 (11)	0.0041 (11)	−0.0025 (11)
C12	0.0704 (18)	0.0447 (14)	0.0568 (16)	0.0015 (13)	0.0184 (14)	0.0058 (13)
C13	0.0594 (16)	0.0397 (14)	0.0665 (17)	−0.0028 (12)	0.0226 (14)	−0.0025 (12)
C14	0.0474 (15)	0.0345 (12)	0.0659 (17)	−0.0024 (10)	0.0230 (14)	0.0004 (11)
C15	0.0647 (17)	0.0372 (13)	0.081 (2)	−0.0035 (12)	0.0301 (16)	−0.0078 (13)
C16	0.086 (2)	0.0496 (18)	0.074 (2)	−0.0129 (17)	0.0246 (19)	−0.0135 (15)
C17	0.074 (2)	0.0609 (19)	0.079 (2)	−0.0137 (17)	0.0080 (17)	0.0017 (17)
C18	0.0557 (18)	0.0620 (19)	0.087 (2)	0.0049 (15)	0.0152 (17)	0.0037 (17)
C19	0.0548 (16)	0.0503 (17)	0.0725 (19)	0.0072 (12)	0.0228 (14)	−0.0027 (13)

Geometric parameters (Å, º)

O1—C2	1.276 (3)	C8—C9	1.366 (5)
N1—C11	1.302 (3)	C8—H8	0.9300
N1—C12	1.460 (3)	C9—C10	1.407 (4)
N1—H1	0.907 (10)	C9—H9	0.9300
N2—C14	1.392 (3)	C11—H11	0.9300
N2—C13	1.437 (3)	C12—C13	1.505 (4)
N2—H2	0.8600	C12—H12A	0.9700
C1—C11	1.397 (4)	C12—H12B	0.9700
C1—C2	1.436 (4)	C13—H13A	0.9700
C1—C10	1.459 (4)	C13—H13B	0.9700
C2—C3	1.427 (4)	C14—C15	1.389 (4)
C3—C4	1.351 (4)	C14—C19	1.391 (4)
C3—H3	0.9300	C15—C16	1.367 (5)
C4—C5	1.428 (5)	C15—H15	0.9300
C4—H4	0.9300	C16—C17	1.370 (5)
C5—C6	1.409 (4)	C16—H16	0.9300
C5—C10	1.410 (4)	C17—C18	1.379 (5)
C6—C7	1.376 (6)	C17—H17	0.9300
C6—H6	0.9300	C18—C19	1.379 (4)
C7—C8	1.368 (6)	C18—H18	0.9300
C7—H7	0.9300	C19—H19	0.9300
C11—N1—C12	125.9 (2)	C5—C10—C1	118.9 (2)
C11—N1—H1	114 (2)	N1—C11—C1	125.0 (2)
C12—N1—H1	120 (2)	N1—C11—H11	117.5
C14—N2—C13	120.8 (2)	C1—C11—H11	117.5
C14—N2—H2	119.6	N1—C12—C13	111.0 (2)
C13—N2—H2	119.6	N1—C12—H12A	109.4
C11—C1—C2	119.1 (2)	C13—C12—H12A	109.4
C11—C1—C10	120.8 (2)	N1—C12—H12B	109.4
C2—C1—C10	120.1 (2)	C13—C12—H12B	109.4
O1—C2—C3	119.9 (2)	H12A—C12—H12B	108.0
O1—C2—C1	122.0 (2)	N2—C13—C12	111.6 (2)
C3—C2—C1	118.0 (2)	N2—C13—H13A	109.3
C4—C3—C2	121.4 (3)	C12—C13—H13A	109.3
C4—C3—H3	119.3	N2—C13—H13B	109.3
C2—C3—H3	119.3	C12—C13—H13B	109.3
C3—C4—C5	122.4 (3)	H13A—C13—H13B	108.0
C3—C4—H4	118.8	C15—C14—C19	117.3 (3)
C5—C4—H4	118.8	C15—C14—N2	119.9 (2)
C6—C5—C10	120.1 (3)	C19—C14—N2	122.8 (2)
C6—C5—C4	120.8 (3)	C16—C15—C14	121.1 (3)
C10—C5—C4	119.1 (3)	C16—C15—H15	119.4
C7—C6—C5	120.4 (4)	C14—C15—H15	119.4
C7—C6—H6	119.8	C15—C16—C17	121.5 (3)
C5—C6—H6	119.8	C15—C16—H16	119.3
C8—C7—C6	119.5 (3)	C17—C16—H16	119.3
C8—C7—H7	120.3	C16—C17—C18	118.3 (3)
C6—C7—H7	120.3	C16—C17—H17	120.9
C9—C8—C7	121.5 (4)	C18—C17—H17	120.9
C9—C8—H8	119.2	C17—C18—C19	120.8 (3)
C7—C8—H8	119.2	C17—C18—H18	119.6
C8—C9—C10	121.3 (4)	C19—C18—H18	119.6
C8—C9—H9	119.4	C18—C19—C14	120.9 (3)
C10—C9—H9	119.4	C18—C19—H19	119.5
C9—C10—C5	117.2 (3)	C14—C19—H19	119.5
C9—C10—C1	123.9 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O1	0.91 (1)	1.84 (3)	2.582 (3)	137 (3)
N2—H2···O1^i	0.86	2.43	3.043 (3)	129

Symmetry code: (i) x, y−1, z.