(E)-2-[(2,4-Dihy-droxy-benzyl-idene)aza-nium-yl]-3-(1H-indol-3-yl)propano-ate monohydrate.

In the zwitterionic title compound, C(18)H(16)N(2)O(4)·H(2)O, the dihedral angle between the planes of the benzene and indole rings is 39.20 (8)°. An intra-molecular N-H⋯O hydrogen bond generates an S(6) ring motif. In the crystal, inter-molecular hy-droxy and water O-H⋯O(carboxyl-ate) and N(+)-H⋯O(carboxyl-ate) and indole N-H⋯O(water) hydrogen bonds give a three-dimensional structure.

Related literature

For related structures, see: Grant et al. (1999 ▶); Emge et al. (2000 ▶). For the anti­cancer activity of Schiff bases, see: Dao et al. (2000 ▶), for their anti-HIV activity, see: Sriram et al. (2006 ▶) and for their anti­bacterial and anti­fungal activity, see: Karthikeyan et al. (2006 ▶). For analytical applications, see: Eltayeb & Ahmed (2005a ▶,b ▶). For standard bond lengths, see: Allen et al. (1987 ▶).

Experimental

Crystal data

C18H16N2O4·H2O

M = 342.34

Orthorhombic,

a = 8.4214 (3) Å

b = 10.6787 (4) Å

c = 18.9554 (8) Å

V = 1704.65 (11) Å3

Z = 4

Mo Kα radiation

μ = 0.10 mm−1

T = 100 K

0.20 × 0.10 × 0.10 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer

Absorption correction: multi-scan (SADABS; Sheldrick, 1996) ▶ T min = 0.618, T max = 0.746

15797 measured reflections

3904 independent reflections

3587 reflections with I > 2σ(I)

R int = 0.035

Refinement

R[F 2 > 2σ(F 2)] = 0.034

wR(F 2) = 0.085

S = 1.03

3904 reflections

244 parameters

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.25 e Å−3

Δρmin = −0.16 e Å−3

Data collection: APEX2 (Bruker, 2008 ▶); cell refinement: SAINT (Bruker, 2008 ▶); data reduction: SAINT; 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: publCIF (Westrip, 2010 ▶).

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536811028200/zs2121sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811028200/zs2121Isup2.hkl

Supplementary material file. DOI: 10.1107/S1600536811028200/zs2121Isup3.cml

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

C18H16N2O4·H2O	F(000) = 720
Mr = 342.34	Dx = 1.334 Mg m−3
Orthorhombic, P212121	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2ab	Cell parameters from 6129 reflections
a = 8.4214 (3) Å	θ = 2.7–28.3°
b = 10.6787 (4) Å	µ = 0.10 mm−1
c = 18.9554 (8) Å	T = 100 K
V = 1704.65 (11) Å3	Block, brown-yellow
Z = 4	0.20 × 0.10 × 0.10 mm

Bruker SMART APEXII CCD area-detector diffractometer	3904 independent reflections
Radiation source: fine-focus sealed tube	3587 reflections with I > 2σ(I)
graphite	Rint = 0.035
φ and ω scans	θmax = 27.5°, θmin = 2.2°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −10→10
Tmin = 0.618, Tmax = 0.746	k = −13→13
15797 measured reflections	l = −24→24

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)] = 0.034	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.085	H atoms treated by a mixture of independent and constrained refinement
S = 1.03	w = 1/[σ2(Fo2) + (0.0474P)2 + 0.2857P] where P = (Fo2 + 2Fc2)/3
3904 reflections	(Δ/σ)max < 0.001
244 parameters	Δρmax = 0.25 e Å−3
0 restraints	Δρmin = −0.16 e Å−3

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.

	x	y	z	Uiso*/Ueq
O4	0.45139 (13)	0.65534 (9)	0.31898 (6)	0.0204 (2)
H4	0.3667	0.6867	0.3036	0.031*
O2	0.19336 (12)	−0.24604 (9)	0.26862 (6)	0.0211 (2)
O3	0.17010 (12)	0.27877 (9)	0.26869 (6)	0.0235 (2)
H3	0.0984	0.3300	0.2579	0.035*
N2	0.29712 (15)	0.06525 (11)	0.31452 (6)	0.0170 (2)
C16	0.43988 (17)	0.53039 (13)	0.31846 (7)	0.0172 (3)
O1	0.04987 (13)	−0.07062 (10)	0.26999 (7)	0.0294 (3)
C18	0.55615 (17)	0.33389 (13)	0.34947 (7)	0.0169 (3)
H18	0.6416	0.2870	0.3689	0.020*
C17	0.56704 (18)	0.46154 (13)	0.34693 (7)	0.0176 (3)
H17	0.6590	0.5031	0.3641	0.021*
C15	0.30669 (18)	0.47039 (13)	0.29074 (7)	0.0184 (3)
H15	0.2236	0.5181	0.2701	0.022*
C13	0.42086 (17)	0.26989 (13)	0.32395 (7)	0.0162 (3)
C12	0.41503 (17)	0.13809 (13)	0.33109 (7)	0.0161 (3)
H12	0.5068	0.0987	0.3500	0.019*
C10	0.29777 (18)	−0.06908 (12)	0.32974 (7)	0.0172 (3)
H10	0.4045	−0.1051	0.3186	0.021*
C11	0.17062 (18)	−0.13330 (13)	0.28460 (7)	0.0192 (3)
C3	0.53472 (19)	−0.05160 (14)	0.46542 (7)	0.0207 (3)
C14	0.29580 (18)	0.34069 (13)	0.29342 (7)	0.0180 (3)
C9	0.25679 (18)	−0.09299 (14)	0.40849 (7)	0.0211 (3)
H9A	0.1471	−0.0642	0.4179	0.025*
H9B	0.2614	−0.1840	0.4181	0.025*
N1	0.47368 (18)	0.12210 (13)	0.52719 (7)	0.0263 (3)
C1	0.33771 (19)	0.07978 (15)	0.49523 (8)	0.0249 (3)
H1	0.2365	0.1185	0.4992	0.030*
C8	0.5967 (2)	0.04331 (15)	0.50975 (8)	0.0231 (3)
C7	0.7571 (2)	0.04678 (16)	0.52806 (8)	0.0273 (4)
H7	0.7982	0.1111	0.5575	0.033*
C4	0.6373 (2)	−0.14419 (15)	0.43870 (8)	0.0244 (3)
H4A	0.5984	−0.2079	0.4083	0.029*
C6	0.85398 (19)	−0.04657 (16)	0.50188 (8)	0.0283 (4)
H6	0.9633	−0.0471	0.5143	0.034*
C5	0.7951 (2)	−0.14071 (17)	0.45741 (8)	0.0279 (3)
H5	0.8653	−0.2031	0.4399	0.033*
C2	0.36843 (18)	−0.02646 (14)	0.45657 (8)	0.0213 (3)
O5	0.41346 (18)	0.32658 (13)	0.62788 (7)	0.0344 (3)
H2A	0.208 (2)	0.0933 (17)	0.2981 (9)	0.023 (4)*
H5B	0.410 (3)	0.311 (2)	0.6689 (16)	0.055 (8)*
H1A	0.476 (3)	0.186 (2)	0.5555 (12)	0.041 (6)*
H5A	0.387 (4)	0.394 (3)	0.6163 (18)	0.083 (11)*

	U11	U22	U33	U12	U13	U23
O4	0.0223 (5)	0.0114 (5)	0.0276 (5)	0.0001 (4)	−0.0034 (5)	−0.0001 (4)
O2	0.0241 (5)	0.0119 (5)	0.0274 (5)	−0.0006 (4)	−0.0056 (4)	−0.0014 (4)
O3	0.0216 (5)	0.0120 (5)	0.0369 (6)	0.0004 (4)	−0.0124 (5)	0.0013 (4)
N2	0.0185 (6)	0.0117 (5)	0.0208 (6)	0.0010 (5)	−0.0045 (5)	0.0001 (4)
C16	0.0220 (7)	0.0119 (6)	0.0176 (6)	−0.0012 (5)	0.0018 (6)	−0.0001 (5)
O1	0.0251 (6)	0.0147 (5)	0.0484 (7)	0.0010 (4)	−0.0173 (5)	−0.0028 (5)
C18	0.0151 (7)	0.0157 (7)	0.0199 (6)	0.0019 (6)	−0.0013 (5)	−0.0006 (5)
C17	0.0184 (7)	0.0149 (7)	0.0196 (6)	−0.0024 (6)	−0.0010 (5)	−0.0024 (5)
C15	0.0207 (7)	0.0141 (7)	0.0204 (6)	0.0023 (6)	−0.0031 (6)	0.0020 (5)
C13	0.0188 (7)	0.0122 (6)	0.0177 (6)	0.0001 (5)	0.0000 (5)	−0.0017 (5)
C12	0.0172 (7)	0.0145 (7)	0.0166 (6)	0.0019 (5)	−0.0003 (5)	−0.0013 (5)
C10	0.0189 (7)	0.0101 (6)	0.0226 (7)	0.0007 (5)	−0.0029 (6)	0.0005 (5)
C11	0.0216 (7)	0.0136 (7)	0.0225 (7)	−0.0024 (6)	−0.0040 (6)	0.0029 (5)
C3	0.0255 (8)	0.0201 (7)	0.0165 (6)	−0.0034 (6)	−0.0016 (6)	0.0037 (6)
C14	0.0193 (7)	0.0152 (7)	0.0194 (6)	0.0000 (6)	−0.0028 (5)	−0.0009 (5)
C9	0.0217 (7)	0.0181 (7)	0.0235 (7)	−0.0021 (6)	−0.0009 (6)	0.0018 (6)
N1	0.0332 (8)	0.0243 (7)	0.0215 (6)	−0.0028 (6)	0.0001 (6)	−0.0055 (5)
C1	0.0275 (8)	0.0253 (8)	0.0218 (7)	−0.0003 (7)	0.0020 (6)	0.0003 (6)
C8	0.0306 (8)	0.0233 (8)	0.0155 (6)	−0.0035 (6)	0.0001 (6)	0.0019 (6)
C7	0.0330 (9)	0.0309 (9)	0.0180 (7)	−0.0082 (7)	−0.0047 (6)	−0.0011 (6)
C4	0.0295 (8)	0.0217 (8)	0.0221 (7)	−0.0003 (7)	−0.0034 (6)	0.0000 (6)
C6	0.0234 (8)	0.0387 (9)	0.0227 (7)	−0.0054 (7)	−0.0050 (6)	0.0013 (7)
C5	0.0285 (9)	0.0294 (8)	0.0257 (8)	0.0024 (7)	−0.0012 (6)	−0.0017 (6)
C2	0.0243 (8)	0.0213 (8)	0.0184 (7)	−0.0048 (6)	0.0002 (6)	0.0031 (6)
O5	0.0503 (8)	0.0244 (7)	0.0286 (7)	−0.0047 (6)	0.0015 (6)	0.0015 (5)

O4—C16	1.3379 (17)	C10—H10	1.0000
O4—H4	0.8400	C3—C4	1.407 (2)
O2—C11	1.2562 (18)	C3—C8	1.416 (2)
O3—C14	1.3333 (17)	C3—C2	1.436 (2)
O3—H3	0.8400	C9—C2	1.490 (2)
N2—C12	1.2999 (18)	C9—H9A	0.9900
N2—C10	1.4631 (17)	C9—H9B	0.9900
N2—H2A	0.87 (2)	N1—C1	1.372 (2)
C16—C15	1.395 (2)	N1—C8	1.375 (2)
C16—C17	1.407 (2)	N1—H1A	0.87 (2)
O1—C11	1.2485 (18)	C1—C2	1.375 (2)
C18—C17	1.367 (2)	C1—H1	0.9500
C18—C13	1.4139 (19)	C8—C7	1.395 (2)
C18—H18	0.9500	C7—C6	1.380 (3)
C17—H17	0.9500	C7—H7	0.9500
C15—C14	1.3890 (19)	C4—C5	1.376 (2)
C15—H15	0.9500	C4—H4A	0.9500
C13—C12	1.4148 (19)	C6—C5	1.403 (2)
C13—C14	1.420 (2)	C6—H6	0.9500
C12—H12	0.9500	C5—H5	0.9500
C10—C11	1.5327 (19)	O5—H5B	0.80 (3)
C10—C9	1.553 (2)	O5—H5A	0.78 (3)
C16—O4—H4	109.5	O3—C14—C15	122.29 (13)
C14—O3—H3	109.5	O3—C14—C13	117.91 (12)
C12—N2—C10	122.42 (12)	C15—C14—C13	119.80 (13)
C12—N2—H2A	122.9 (12)	C2—C9—C10	111.67 (12)
C10—N2—H2A	114.4 (12)	C2—C9—H9A	109.3
O4—C16—C15	121.28 (13)	C10—C9—H9A	109.3
O4—C16—C17	117.60 (13)	C2—C9—H9B	109.3
C15—C16—C17	121.11 (12)	C10—C9—H9B	109.3
C17—C18—C13	121.60 (14)	H9A—C9—H9B	107.9
C17—C18—H18	119.2	C1—N1—C8	108.72 (13)
C13—C18—H18	119.2	C1—N1—H1A	123.3 (15)
C18—C17—C16	118.93 (13)	C8—N1—H1A	127.9 (15)
C18—C17—H17	120.5	N1—C1—C2	110.49 (14)
C16—C17—H17	120.5	N1—C1—H1	124.8
C14—C15—C16	119.83 (13)	C2—C1—H1	124.8
C14—C15—H15	120.1	N1—C8—C7	130.80 (15)
C16—C15—H15	120.1	N1—C8—C3	107.65 (14)
C18—C13—C12	118.43 (13)	C7—C8—C3	121.55 (15)
C18—C13—C14	118.68 (12)	C6—C7—C8	117.62 (15)
C12—C13—C14	122.89 (13)	C6—C7—H7	121.2
N2—C12—C13	126.78 (13)	C8—C7—H7	121.2
N2—C12—H12	116.6	C5—C4—C3	118.77 (15)
C13—C12—H12	116.6	C5—C4—H4A	120.6
N2—C10—C11	109.03 (11)	C3—C4—H4A	120.6
N2—C10—C9	110.48 (11)	C7—C6—C5	121.64 (15)
C11—C10—C9	107.92 (11)	C7—C6—H6	119.2
N2—C10—H10	109.8	C5—C6—H6	119.2
C11—C10—H10	109.8	C4—C5—C6	121.05 (16)
C9—C10—H10	109.8	C4—C5—H5	119.5
O1—C11—O2	125.77 (13)	C6—C5—H5	119.5
O1—C11—C10	116.93 (12)	C1—C2—C3	105.99 (14)
O2—C11—C10	117.20 (12)	C1—C2—C9	126.92 (14)
C4—C3—C8	119.35 (15)	C3—C2—C9	126.72 (14)
C4—C3—C2	133.49 (15)	H5B—O5—H5A	117 (3)
C8—C3—C2	107.15 (14)
C13—C18—C17—C16	0.3 (2)	C11—C10—C9—C2	−176.14 (12)
O4—C16—C17—C18	177.64 (13)	C8—N1—C1—C2	−0.01 (18)
C15—C16—C17—C18	−2.3 (2)	C1—N1—C8—C7	179.16 (16)
O4—C16—C15—C14	−177.57 (14)	C1—N1—C8—C3	−0.11 (17)
C17—C16—C15—C14	2.4 (2)	C4—C3—C8—N1	178.89 (13)
C17—C18—C13—C12	−177.31 (14)	C2—C3—C8—N1	0.19 (16)
C17—C18—C13—C14	1.6 (2)	C4—C3—C8—C7	−0.5 (2)
C10—N2—C12—C13	−174.50 (13)	C2—C3—C8—C7	−179.16 (14)
C18—C13—C12—N2	175.73 (14)	N1—C8—C7—C6	−179.74 (15)
C14—C13—C12—N2	−3.2 (2)	C3—C8—C7—C6	−0.6 (2)
C12—N2—C10—C11	−162.62 (12)	C8—C3—C4—C5	0.9 (2)
C12—N2—C10—C9	78.95 (17)	C2—C3—C4—C5	179.23 (16)
N2—C10—C11—O1	−31.31 (18)	C8—C7—C6—C5	1.1 (2)
C9—C10—C11—O1	88.72 (15)	C3—C4—C5—C6	−0.4 (2)
N2—C10—C11—O2	152.17 (13)	C7—C6—C5—C4	−0.6 (3)
C9—C10—C11—O2	−87.79 (16)	N1—C1—C2—C3	0.13 (17)
C16—C15—C14—O3	178.95 (13)	N1—C1—C2—C9	−173.23 (14)
C16—C15—C14—C13	−0.4 (2)	C4—C3—C2—C1	−178.63 (16)
C18—C13—C14—O3	179.05 (12)	C8—C3—C2—C1	−0.20 (16)
C12—C13—C14—O3	−2.1 (2)	C4—C3—C2—C9	−5.2 (3)
C18—C13—C14—C15	−1.5 (2)	C8—C3—C2—C9	173.18 (14)
C12—C13—C14—C15	177.34 (14)	C10—C9—C2—C1	105.32 (17)
N2—C10—C9—C2	−57.03 (16)	C10—C9—C2—C3	−66.71 (19)

D—H···A	D—H	H···A	D···A	D—H···A
O4—H4···O2i	0.84	1.76	2.5966 (15)	178.
O3—H3···O1ii	0.84	1.72	2.5605 (15)	176.
O3—H3···O2ii	0.84	2.64	3.1526 (14)	121.
N2—H2A···O3	0.87 (2)	2.082 (19)	2.6642 (15)	123.9 (16)
O5—H5B···O2iii	0.80 (3)	2.19 (3)	2.9438 (17)	157 (2)
N1—H1A···O5	0.87 (2)	2.10 (2)	2.9441 (19)	164 (2)

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O4—H4⋯O2i	0.84	1.76	2.5966 (15)	178
O3—H3⋯O1ii	0.84	1.72	2.5605 (15)	176
O3—H3⋯O2ii	0.84	2.64	3.1526 (14)	121
N2—H2A⋯O3	0.87 (2)	2.082 (19)	2.6642 (15)	123.9 (16)
O5—H5B⋯O2iii	0.80 (3)	2.19 (3)	2.9438 (17)	157 (2)
N1—H1A⋯O5	0.87 (2)	2.10 (2)	2.9441 (19)	164 (2)

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