2-Hy-droxy-5-[(E)-(1H-indol-3-yl-methyl-idene)aza-nium-yl]benzoate.

The zwitterionic title compound, C(16)H(12)N(2)O(3), was obtained as a result of the condensation of 5-amino-salicylic acid and 1H-indole-3-carbaldehyde. The whole mol-ecule is roughly planar: the 4-hy-droxy-anilinic group and the 1H-indole-3-carbaldehyde moieties are only slightly twisted, making a dihedral angle of 7.77 (11)°, whereas, the carboxyl-ate group makes a dihedral angle of 3.34 (45)° with the parent 4-hy-droxy-anilinic group. S(6) ring motifs are formed due to intra-molecular O-H⋯O hydrogen bonding. In the crystal, inter-molecular N-H⋯O and C-H⋯O hydrogen bonds build up pseudo-rings with R(1) (2)(4), R(2) (1)(7) and R(2) (2)(14) ring motifs. These pseudo-dimers are further linked by N-H⋯O hydrogen bonds into a chain extending along [101]. C-H⋯π inter-actions also occur, along with offset π-π inter-actions between the anilinic phenyl and the heterocyclic five-membered rings with a centroid-centroid distance of 3.5716 (19) Å.

Related literature

For background to our ongoing work on the synthesis and ligand properties of Schiff bases derived from 2-hydroxy-5-aminobenzoic acid, see: Tahir et al. (2010 ▶). For graph-set notation, see: Bernstein et al. (1995 ▶); Etter (1990 ▶).

Experimental

Crystal data

C16H12N2O3

M = 280.28

Monoclinic,

a = 7.3463 (6) Å

b = 15.5496 (12) Å

c = 11.5310 (8) Å

β = 104.619 (4)°

V = 1274.57 (17) Å3

Z = 4

Mo Kα radiation

μ = 0.10 mm−1

T = 296 K

0.24 × 0.14 × 0.12 mm

Data collection

Bruker Kappa APEXII CCD diffractometer

Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T min = 0.980, T max = 0.988

9888 measured reflections

2313 independent reflections

1169 reflections with I > 2σ(I)

R int = 0.080

Refinement

R[F 2 > 2σ(F 2)] = 0.057

wR(F 2) = 0.152

S = 1.00

2313 reflections

191 parameters

H-atom parameters constrained

Δρmax = 0.19 e Å−3

Δρmin = −0.22 e Å−3

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2009 ▶); data reduction: SAINT; 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.

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810048579/dn2627sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810048579/dn2627Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

C16H12N2O3	F(000) = 584
Mr = 280.28	Dx = 1.461 Mg m−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 1169 reflections
a = 7.3463 (6) Å	θ = 2.3–25.3°
b = 15.5496 (12) Å	µ = 0.10 mm−1
c = 11.5310 (8) Å	T = 296 K
β = 104.619 (4)°	Needle, orange
V = 1274.57 (17) Å3	0.24 × 0.14 × 0.12 mm
Z = 4

Bruker Kappa APEXII CCD diffractometer	2313 independent reflections
Radiation source: fine-focus sealed tube	1169 reflections with I > 2σ(I)
graphite	Rint = 0.080
Detector resolution: 8.20 pixels mm-1	θmax = 25.3°, θmin = 2.3°
ω scans	h = −8→8
Absorption correction: multi-scan (SADABS; Bruker, 2005)	k = −18→18
Tmin = 0.980, Tmax = 0.988	l = −13→13
9888 measured reflections

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.057	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.152	H-atom parameters constrained
S = 1.00	w = 1/[σ2(Fo2) + (0.0622P)2] where P = (Fo2 + 2Fc2)/3
2313 reflections	(Δ/σ)max < 0.001
191 parameters	Δρmax = 0.19 e Å−3
0 restraints	Δρmin = −0.22 e Å−3

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

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.

	x	y	z	Uiso*/Ueq
O1	1.2830 (3)	0.00635 (16)	0.14061 (19)	0.0527 (10)
O2	1.3616 (3)	0.01396 (16)	0.34045 (19)	0.0529 (10)
O3	1.1429 (3)	0.07152 (17)	0.44973 (17)	0.0486 (9)
N1	0.6066 (4)	0.10087 (18)	0.0169 (2)	0.0394 (10)
N2	0.1653 (4)	0.11644 (18)	−0.3115 (2)	0.0408 (10)
C1	1.2446 (5)	0.0237 (2)	0.2380 (3)	0.0375 (12)
C2	1.0566 (4)	0.0584 (2)	0.2369 (3)	0.0334 (11)
C3	1.0142 (5)	0.0819 (2)	0.3454 (3)	0.0364 (11)
C4	0.8368 (5)	0.1138 (2)	0.3417 (3)	0.0459 (13)
C5	0.7012 (5)	0.1219 (2)	0.2364 (3)	0.0424 (14)
C6	0.7423 (4)	0.0983 (2)	0.1288 (3)	0.0338 (11)
C7	0.9190 (4)	0.0666 (2)	0.1312 (3)	0.0349 (11)
C8	0.4406 (5)	0.1355 (2)	−0.0070 (3)	0.0387 (11)
C9	0.3080 (5)	0.1370 (2)	−0.1184 (3)	0.0344 (11)
C10	0.1205 (4)	0.1715 (2)	−0.1405 (3)	0.0324 (11)
C11	0.0164 (5)	0.2123 (2)	−0.0705 (3)	0.0410 (11)
C12	−0.1644 (5)	0.2377 (2)	−0.1229 (3)	0.0451 (12)
C13	−0.2477 (5)	0.2216 (2)	−0.2434 (3)	0.0476 (14)
C14	−0.1494 (5)	0.1805 (2)	−0.3140 (3)	0.0411 (11)
C15	0.0346 (5)	0.1569 (2)	−0.2617 (3)	0.0350 (11)
C16	0.3256 (5)	0.1038 (2)	−0.2278 (3)	0.0411 (12)
H1	0.63809	0.07659	−0.04221	0.0472*
H2	0.14581	0.10162	−0.38548	0.0489*
H3	1.24072	0.05315	0.43705	0.0584*
H4	0.80901	0.13014	0.41293	0.0551*
H5	0.58271	0.14295	0.23633	0.0512*
H7	0.94585	0.05043	0.05962	0.0420*
H8	0.40583	0.16216	0.05637	0.0463*
H11	0.06906	0.22218	0.01060	0.0494*
H12	−0.23290	0.26623	−0.07704	0.0542*
H13	−0.37122	0.23872	−0.27642	0.0567*
H14	−0.20470	0.16904	−0.39435	0.0495*
H16	0.43238	0.07717	−0.24027	0.0491*

	U11	U22	U33	U12	U13	U23
O1	0.0458 (16)	0.076 (2)	0.0390 (14)	0.0109 (13)	0.0160 (12)	−0.0088 (13)
O2	0.0373 (15)	0.079 (2)	0.0397 (15)	0.0091 (13)	0.0048 (12)	−0.0035 (14)
O3	0.0402 (16)	0.0743 (19)	0.0303 (13)	0.0077 (14)	0.0070 (11)	−0.0027 (12)
N1	0.0406 (19)	0.0466 (19)	0.0307 (15)	0.0039 (16)	0.0087 (13)	−0.0042 (14)
N2	0.0439 (19)	0.0481 (19)	0.0292 (15)	0.0048 (15)	0.0071 (14)	−0.0045 (14)
C1	0.036 (2)	0.040 (2)	0.035 (2)	0.0021 (17)	0.0063 (17)	−0.0006 (17)
C2	0.034 (2)	0.036 (2)	0.0306 (18)	−0.0016 (16)	0.0087 (15)	−0.0013 (16)
C3	0.037 (2)	0.041 (2)	0.0285 (18)	0.0015 (18)	0.0033 (16)	0.0003 (16)
C4	0.050 (2)	0.060 (3)	0.0279 (18)	0.008 (2)	0.0104 (17)	−0.0090 (18)
C5	0.037 (2)	0.054 (3)	0.036 (2)	0.0112 (18)	0.0086 (16)	−0.0048 (18)
C6	0.035 (2)	0.038 (2)	0.0260 (17)	0.0012 (17)	0.0031 (15)	−0.0027 (16)
C7	0.034 (2)	0.042 (2)	0.0295 (18)	0.0013 (16)	0.0093 (15)	−0.0038 (16)
C8	0.041 (2)	0.040 (2)	0.0348 (19)	0.0065 (18)	0.0090 (16)	0.0011 (17)
C9	0.036 (2)	0.037 (2)	0.0288 (17)	0.0008 (16)	0.0056 (15)	−0.0030 (16)
C10	0.037 (2)	0.031 (2)	0.0279 (18)	−0.0014 (16)	0.0058 (15)	0.0007 (15)
C11	0.048 (2)	0.042 (2)	0.0332 (19)	0.0006 (19)	0.0109 (17)	−0.0011 (17)
C12	0.044 (2)	0.048 (2)	0.047 (2)	0.0103 (19)	0.0181 (18)	0.0001 (19)
C13	0.040 (2)	0.056 (3)	0.045 (2)	0.0095 (19)	0.0075 (18)	0.004 (2)
C14	0.043 (2)	0.047 (2)	0.0308 (19)	0.0011 (19)	0.0047 (17)	0.0003 (17)
C15	0.037 (2)	0.034 (2)	0.0352 (19)	0.0039 (17)	0.0115 (16)	0.0028 (16)
C16	0.037 (2)	0.046 (2)	0.038 (2)	0.0066 (18)	0.0050 (17)	−0.0019 (18)

O1—C1	1.254 (4)	C9—C10	1.440 (5)
O2—C1	1.283 (4)	C9—C16	1.399 (5)
O3—C3	1.339 (4)	C10—C15	1.399 (5)
O3—H3	0.8200	C10—C11	1.397 (5)
N1—C6	1.418 (4)	C11—C12	1.371 (5)
N1—C8	1.298 (5)	C12—C13	1.392 (5)
N2—C16	1.335 (4)	C13—C14	1.375 (5)
N2—C15	1.388 (5)	C14—C15	1.384 (5)
N1—H1	0.8600	C4—H4	0.9300
N2—H2	0.8600	C5—H5	0.9300
C1—C2	1.480 (5)	C7—H7	0.9300
C2—C7	1.379 (5)	C8—H8	0.9300
C2—C3	1.412 (5)	C11—H11	0.9300
C3—C4	1.385 (5)	C12—H12	0.9300
C4—C5	1.368 (5)	C13—H13	0.9300
C5—C6	1.398 (5)	C14—H14	0.9300
C6—C7	1.382 (4)	C16—H16	0.9300
C8—C9	1.403 (5)
C3—O3—H3	109.00	C9—C10—C11	134.9 (3)
C6—N1—C8	127.8 (3)	C10—C11—C12	119.1 (3)
C15—N2—C16	110.1 (3)	C11—C12—C13	121.4 (3)
C8—N1—H1	116.00	C12—C13—C14	120.7 (3)
C6—N1—H1	116.00	C13—C14—C15	117.8 (3)
C16—N2—H2	125.00	C10—C15—C14	122.5 (3)
C15—N2—H2	125.00	N2—C15—C10	107.6 (3)
O2—C1—C2	117.3 (3)	N2—C15—C14	129.9 (3)
O1—C1—O2	123.3 (3)	N2—C16—C9	109.4 (3)
O1—C1—C2	119.4 (3)	C3—C4—H4	119.00
C3—C2—C7	118.9 (3)	C5—C4—H4	119.00
C1—C2—C3	120.1 (3)	C4—C5—H5	120.00
C1—C2—C7	121.0 (3)	C6—C5—H5	120.00
O3—C3—C4	121.1 (3)	C2—C7—H7	119.00
O3—C3—C2	120.1 (3)	C6—C7—H7	119.00
C2—C3—C4	118.8 (3)	N1—C8—H8	117.00
C3—C4—C5	121.9 (3)	C9—C8—H8	117.00
C4—C5—C6	119.4 (3)	C10—C11—H11	120.00
C5—C6—C7	119.2 (3)	C12—C11—H11	120.00
N1—C6—C5	122.7 (3)	C11—C12—H12	119.00
N1—C6—C7	118.0 (3)	C13—C12—H12	119.00
C2—C7—C6	121.7 (3)	C12—C13—H13	120.00
N1—C8—C9	126.8 (3)	C14—C13—H13	120.00
C8—C9—C10	125.5 (3)	C13—C14—H14	121.00
C8—C9—C16	128.2 (3)	C15—C14—H14	121.00
C10—C9—C16	106.3 (3)	N2—C16—H16	125.00
C11—C10—C15	118.4 (3)	C9—C16—H16	125.00
C9—C10—C15	106.7 (3)

Cg3 is the centroid of the C10–C15 ring.

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O1i	0.86	1.90	2.735 (3)	162
N2—H2···O3ii	0.86	1.95	2.805 (3)	171
O3—H3···O2	0.82	1.70	2.448 (3)	150
C16—H16···O1i	0.93	2.48	3.279 (4)	144
C16—H16···O2i	0.93	2.55	3.439 (4)	160
C5—H5···Cg3iii	0.93	2.92	3.643 (4)	136

Table 1

Hydrogen-bond geometry (Å, °)

Cg3 is the centroid of the C10–C15 ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯O1i	0.86	1.90	2.735 (3)	162
N2—H2⋯O3ii	0.86	1.95	2.805 (3)	171
O3—H3⋯O2	0.82	1.70	2.448 (3)	150
C16—H16⋯O1i	0.93	2.48	3.279 (4)	144
C16—H16⋯O2i	0.93	2.55	3.439 (4)	160
C5—H5⋯Cg3iii	0.93	2.92	3.643 (4)	136

Symmetry codes: (i) ; (ii) ; (iii) .