2-Hy­droxy-5-{[(E)-4-meth­oxy­benzyl­idene]aza­nium­yl}benzoate

In the title zwitterion, C₁₅H₁₃NO₄, obtained from the condensation of 5-amino­salicylic acid and 4-meth­oxy­benz­alde­hyde, the 4-hydoxyanilinic group of the 5-amino­salicylic acid moiety and the 4-meth­oxy­benzaldehyde moiety are twisted with respect to one another, making a dihedral angle of 10.37 (7)°. The carboxyl­ate group makes a dihedral angle of 5.7 (2)° with the parent 4-hydoxyanilinic group. An intra­molecular O—H...O hydrogen bond forms an S(6) ring motif. In the crystal, inter­molecular C—H...O and N—H...O hydrogen bonds with R₂¹(7) ring motifs link the mol­ecules into infinite chains extending along the c axis. The occurence of slipped π–π stacking between symmetry-related aromatic rings reinforces the packing.

Key indicators

• Single-crystal X-ray study
• T = 296 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.050
• wR factor = 0.143
• Data-to-parameter ratio = 12.7

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT910_ALERT_3_C Missing # of FCF Reflections Below Th(Min) .....          1
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.600          7
PLAT913_ALERT_3_C Missing # of Very Strong Reflections in FCF ....          3

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

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

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S1. Comment

The title compound (I) has been synthesized as a potential ligand which could be used with various metals.

The title compound (I) is a Zwitterion. In (I), the group A (C2—C7/N1/O3) of 5-aminosalicylic acid moiety and the 4-methoxybenzaldehyde moiety B (C8—C15/O4) are planar with r. m. s. deviations of 0.0076 and 0.0255 Å, respectively. The dihedral angle between A/B is 10.37 (7)°. The carboxylate group C (O1/C1/O2) is oriented at a dihedral angle of 5.73 (24)° with the parent group A (Fig. 1). The title molecule is closely related to p-[(p-methoxybenzylidene)amino]phenol (Bryan et al., 1978) and N-benzyl-N'-{6- [(4-carboxylatobenzyl)aminocarbonyl]-2-pyridylmethyl}guanidinium (Ashiq et al., 2010)

The values of the C═O bond [1.241 (2), 1.269 (3) Å] are in agreement with the value, 1.235 (3)–1.261 (3) Å, reported for the N-benzyl-N'-{6- [(4-carboxylatobenzyl)aminocarbonyl]-2-pyridylmethyl}guanidinium (Ashiq et al., 2010). In the title compound S(6) ring motifs (Bernstein et al., 1995), is formed due to intramolecular H-bondings of O—H···O type (Table 1, Fig. 2). There exist R₂¹(7) ring motif due to intermolecular H-bondings of C—H···O and N—H···O types linking the molecules to form infinite one dimensional chains extending along the crystallographic c-axis.

The occurence of slippest π–π stacking (Janiak, 2000) between symmetry related aromatic rings play an important role in stabilizing the packing.

Related literature

For the related structures, see: Ashiq et al. (2010); Bryan et al. (1978). For graph-set notation, see: Bernstein et al. (1995). For π–π stacking, see: Janiak (2000).

S2. Experimental

Equimolar quantities of 5-aminosalicylic acid and 4-anisaldehyde were refluxed in methanol for 30 min resulting in clear brown solution. The solution was kept at room temperature which affoarded light brown prisms after 72 h.

S3. Refinement

All H atoms attached to C atoms and N atom were fixed geometrically and treated as riding with C—H = 0.95 Å (methyl) or 0.93 Å (aromatic) and N—H = 0.86 Å with U_iso(H) = 1.2U_eq(C_aromatic or N) or U_iso(H) = 1.5U_eq(C_methyl). H atoms of the hydroxyl group was located in difference Fourier maps and included in the subsequent refinement using restraints (O—H = 0.85 (1) Å) with U_iso(H) = 1.5U_eq(O). In the last cycles of refinement this hydrogen was treated as riding on its parent O atom.

Computing details

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and PLATON (Spek, 2009); software used to prepare material for publication: WinGX (Farrugia, 1999) and PLATON (Spek, 2009).

Figures

	Fig. 1. View of the title compound with the atom numbering scheme. The thermal ellipsoids are drawn at the 50% probability level. H-atoms are shown by small circles of arbitrary radii.
	Fig. 2. Partial packing view showing the hydrogen bonding pattern. Hydrogen bonds are shown as dashed lines. H atoms not involved in hydrogen bondngs have been omitted for clarity. [Symmetry codes: (i) x, -y+1/2, z-1/2; (ii) -x, y-1/2, -z+1/2; (iii) x+1, y-1, z].

2-Hydroxy-5-{[(E)-4-methoxybenzylidene]azaniumyl}benzoate

Crystal data

C15H13NO4	F(000) = 568
Mr = 271.26	Dx = 1.401 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 1583 reflections
a = 13.4369 (12) Å	θ = 2.9–25.3°
b = 8.5619 (8) Å	µ = 0.10 mm^−1
c = 12.6653 (11) Å	T = 296 K
β = 118.004 (3)°	Prism, light brown
V = 1286.5 (2) Å^3	0.26 × 0.20 × 0.18 mm
Z = 4

Data collection

Bruker Kappa APEXII CCD diffractometer	2320 independent reflections
Radiation source: fine-focus sealed tube	1583 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.031
Detector resolution: 8.10 pixels mm^-1	θmax = 25.3°, θmin = 2.9°
ω scans	h = −15→16
Absorption correction: multi-scan (SADABS; Bruker, 2005)	k = −10→10
Tmin = 0.982, Tmax = 0.987	l = −15→10
9561 measured reflections

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)] = 0.050	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.143	H-atom parameters constrained
S = 1.02	w = 1/[σ^2(Fo^2) + (0.0831P)^2 + 0.1187P] where P = (Fo^2 + 2Fc^2)/3
2320 reflections	(Δ/σ)max < 0.001
182 parameters	Δρmax = 0.28 e Å^−3
0 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 > 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	−0.19046 (12)	0.62390 (19)	0.15961 (12)	0.0667 (5)
O2	−0.03306 (11)	0.49725 (16)	0.27753 (10)	0.0510 (4)
O3	−0.29868 (11)	0.56256 (18)	−0.05677 (12)	0.0613 (5)
H3	−0.2728	0.6015	0.0176	0.092*
O4	0.50744 (13)	−0.1897 (2)	0.09919 (15)	0.0857 (6)
N1	0.04782 (11)	0.17725 (17)	−0.01733 (13)	0.0405 (4)
H1	0.0329	0.1255	−0.0813	0.049*
C1	−0.11320 (15)	0.5260 (2)	0.17761 (15)	0.0406 (5)
C2	−0.11993 (13)	0.4447 (2)	0.06936 (14)	0.0353 (4)
C3	−0.21322 (15)	0.4691 (2)	−0.04323 (16)	0.0437 (5)
C4	−0.21754 (16)	0.3965 (3)	−0.14312 (17)	0.0548 (6)
H4	−0.2793	0.4128	−0.2178	0.066*
C5	−0.13155 (15)	0.3009 (2)	−0.13273 (16)	0.0507 (5)
H5	−0.1350	0.2530	−0.2002	0.061*
C6	−0.03929 (14)	0.2756 (2)	−0.02139 (15)	0.0382 (4)
C7	−0.03399 (13)	0.3462 (2)	0.07921 (15)	0.0371 (4)
H7	0.0273	0.3276	0.1537	0.044*
C8	0.14683 (14)	0.1574 (2)	0.07203 (16)	0.0421 (5)
H8	0.1627	0.2105	0.1423	0.051*
C9	0.23438 (14)	0.0614 (2)	0.07311 (16)	0.0413 (5)
C10	0.33683 (16)	0.0561 (3)	0.17828 (17)	0.0548 (6)
H10	0.3447	0.1116	0.2449	0.066*
C11	0.42584 (16)	−0.0289 (3)	0.18534 (18)	0.0633 (7)
H11	0.4934	−0.0315	0.2562	0.076*
C12	0.41467 (16)	−0.1115 (3)	0.08600 (18)	0.0547 (6)
C13	0.31336 (17)	−0.1093 (3)	−0.01877 (18)	0.0541 (5)
H13	0.3056	−0.1665	−0.0846	0.065*
C14	0.22442 (16)	−0.0231 (2)	−0.02569 (17)	0.0476 (5)
H14	0.1570	−0.0209	−0.0967	0.057*
C15	0.5007 (2)	−0.2741 (4)	−0.0010 (3)	0.1025 (10)
H15A	0.5716	−0.3243	0.0206	0.154*
H15B	0.4836	−0.2032	−0.0660	0.154*
H15C	0.4424	−0.3515	−0.0250	0.154*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0623 (9)	0.0904 (12)	0.0448 (8)	0.0283 (9)	0.0230 (7)	−0.0037 (8)
O2	0.0533 (8)	0.0604 (9)	0.0315 (7)	0.0028 (7)	0.0135 (6)	0.0023 (6)
O3	0.0447 (8)	0.0827 (11)	0.0461 (8)	0.0220 (7)	0.0127 (7)	−0.0035 (7)
O4	0.0628 (10)	0.1237 (15)	0.0748 (11)	0.0473 (10)	0.0358 (9)	0.0216 (11)
N1	0.0403 (8)	0.0448 (9)	0.0360 (8)	0.0020 (7)	0.0176 (7)	−0.0029 (7)
C1	0.0401 (10)	0.0465 (11)	0.0365 (10)	−0.0018 (9)	0.0189 (9)	0.0033 (8)
C2	0.0337 (9)	0.0390 (10)	0.0332 (9)	−0.0022 (8)	0.0157 (8)	0.0026 (8)
C3	0.0361 (9)	0.0522 (12)	0.0392 (10)	0.0055 (9)	0.0147 (8)	0.0013 (9)
C4	0.0436 (11)	0.0728 (14)	0.0321 (10)	0.0118 (11)	0.0046 (9)	−0.0036 (10)
C5	0.0472 (11)	0.0620 (13)	0.0345 (10)	0.0066 (10)	0.0120 (9)	−0.0085 (9)
C6	0.0360 (9)	0.0402 (10)	0.0388 (10)	0.0019 (8)	0.0177 (8)	0.0009 (8)
C7	0.0320 (9)	0.0417 (10)	0.0332 (9)	−0.0005 (8)	0.0118 (8)	0.0050 (8)
C8	0.0408 (10)	0.0478 (11)	0.0362 (10)	−0.0014 (9)	0.0168 (8)	−0.0032 (8)
C9	0.0369 (10)	0.0465 (11)	0.0385 (10)	0.0012 (8)	0.0161 (8)	0.0009 (8)
C10	0.0445 (11)	0.0755 (15)	0.0372 (11)	0.0052 (10)	0.0131 (9)	−0.0055 (10)
C11	0.0399 (11)	0.0946 (18)	0.0445 (12)	0.0129 (11)	0.0108 (10)	0.0063 (12)
C12	0.0457 (11)	0.0698 (14)	0.0526 (13)	0.0199 (11)	0.0264 (10)	0.0174 (11)
C13	0.0569 (12)	0.0628 (13)	0.0435 (11)	0.0120 (11)	0.0243 (10)	0.0011 (10)
C14	0.0393 (10)	0.0557 (12)	0.0399 (10)	0.0071 (9)	0.0120 (9)	−0.0008 (9)
C15	0.103 (2)	0.123 (2)	0.107 (2)	0.0604 (19)	0.0700 (18)	0.0201 (19)

Geometric parameters (Å, º)

O1—C1	1.269 (2)	C6—C7	1.381 (2)
O2—C1	1.242 (2)	C7—H7	0.9300
O3—C3	1.343 (2)	C8—C9	1.430 (2)
O3—H3	0.9015	C8—H8	0.9300
O4—C12	1.354 (2)	C9—C10	1.396 (2)
O4—C15	1.426 (3)	C9—C14	1.396 (3)
N1—C8	1.291 (2)	C10—C11	1.367 (3)
N1—C6	1.423 (2)	C10—H10	0.9300
N1—H1	0.8600	C11—C12	1.389 (3)
C1—C2	1.502 (2)	C11—H11	0.9300
C2—C7	1.388 (2)	C12—C13	1.385 (3)
C2—C3	1.404 (2)	C13—C14	1.372 (3)
C3—C4	1.386 (3)	C13—H13	0.9300
C4—C5	1.371 (3)	C14—H14	0.9300
C4—H4	0.9300	C15—H15A	0.9600
C5—C6	1.390 (2)	C15—H15B	0.9600
C5—H5	0.9300	C15—H15C	0.9600
C3—O3—H3	101.5	N1—C8—H8	117.0
C12—O4—C15	118.07 (18)	C9—C8—H8	117.0
C8—N1—C6	126.96 (16)	C10—C9—C14	118.36 (17)
C8—N1—H1	116.5	C10—C9—C8	117.77 (17)
C6—N1—H1	116.5	C14—C9—C8	123.85 (16)
O2—C1—O1	123.99 (17)	C11—C10—C9	121.33 (19)
O2—C1—C2	119.34 (16)	C11—C10—H10	119.3
O1—C1—C2	116.65 (15)	C9—C10—H10	119.3
C7—C2—C3	119.37 (16)	C10—C11—C12	119.54 (18)
C7—C2—C1	120.59 (15)	C10—C11—H11	120.2
C3—C2—C1	120.04 (15)	C12—C11—H11	120.2
O3—C3—C4	118.93 (16)	O4—C12—C13	124.0 (2)
O3—C3—C2	121.38 (16)	O4—C12—C11	115.99 (18)
C4—C3—C2	119.68 (16)	C13—C12—C11	120.05 (18)
C5—C4—C3	120.52 (17)	C14—C13—C12	120.22 (19)
C5—C4—H4	119.7	C14—C13—H13	119.9
C3—C4—H4	119.7	C12—C13—H13	119.9
C4—C5—C6	120.05 (17)	C13—C14—C9	120.49 (17)
C4—C5—H5	120.0	C13—C14—H14	119.8
C6—C5—H5	120.0	C9—C14—H14	119.8
C7—C6—C5	120.18 (16)	O4—C15—H15A	109.5
C7—C6—N1	122.70 (15)	O4—C15—H15B	109.5
C5—C6—N1	117.12 (16)	H15A—C15—H15B	109.5
C6—C7—C2	120.18 (15)	O4—C15—H15C	109.5
C6—C7—H7	119.9	H15A—C15—H15C	109.5
C2—C7—H7	119.9	H15B—C15—H15C	109.5
N1—C8—C9	126.07 (17)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3···O1	0.90	1.62	2.4816 (19)	159
N1—H1···O2^i	0.86	1.90	2.7408 (19)	166
C8—H8···O1^ii	0.93	2.47	3.179 (2)	133
C14—H14···O2^i	0.93	2.30	3.183 (2)	159
C15—H15A···O3^iii	0.96	2.56	3.393 (3)	145

Symmetry codes: (i) x, −y+1/2, z−1/2; (ii) −x, y−1/2, −z+1/2; (iii) x+1, y−1, z.