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organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 67| Part 9| September 2011| Page o2389
doi:10.1107/S1600536811031709

(E)-2-{[1-Carb­­oxy-2-(1H-indol-3-yl)ethyl­iminio]meth­yl}-6-hy­dr­oxy­phenolate

Salah Ahmed Ba-Salamah,a Naser Eltaher Eltayeb,a,b Siang Guan Teoha* and Kong Mun Loc

aSchool of Chemical Sciences, Universiti Sains Malaysia, Minden, Penang, Malaysia, bDepartment of Chemistry, International University of Africa, Sudan, and cChemistry Department, Faculty of Science, University of Malaya, Malaysia
*Correspondence e-mail: sgteoh@usm.my

(Received 4 August 2011; accepted 5 August 2011; online 27 August 2011)

In the zwitterionic title compound, C18H16N2O4, the dihedral angle between the planes of the benzene and indole rings is 26.38 (10)°. An intra­molecular N—H⋯O hydrogen bond generates an S(6) ring motif. In the crystal, mol­ecules are linked through N—H⋯O, O—H⋯O and C—H⋯O hydrogen bonds into infinite chains propagating in [010].

Related literature

For a related structure and background to Schiff bases, see: Ba-Salamah et al. (2011[Ba-Salamah, S. A., Eltayeb, N. E., Teoh, S. G. & Lo, K. M. (2011). Acta Cryst. E67, o2113-o2114.]). For other related structures, see: Eltayeb et al. (2010a[Eltayeb, N. E., Teoh, S. G., Chantrapromma, S. & Fun, H.-K. (2010a). Acta Cryst. E66, o934-o935.],b[Eltayeb, N. E., Teoh, S. G., Fun, H.-K. & Chantrapromma, S. (2010b). Acta Cryst. E66, o1262-o1263.],c[Eltayeb, N. E., Teoh, S. G., Fun, H.-K. & Chantrapromma, S. (2010c). Acta Cryst. E66, o1536-o1537.]). For reference bond lengths, see: Allen et al. (1987[Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1-19.]). For graph-set theory, see: Bernstein et al. (1995[Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555-1573.]).

[Scheme 1]

Experimental

Crystal data

  • C18H16N2O4

  • Mr = 324.33

  • Monoclinic, P 21

  • a = 8.4351 (2) Å

  • b = 9.3038 (3) Å

  • c = 9.5023 (3) Å

  • β = 98.683 (2)°

  • V = 737.18 (4) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 0.11 mm−1

  • T = 100 K

  • 0.32 × 0.22 × 0.20 mm
Data collection

  • Bruker SMART APEXII CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2009[Bruker (2009). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.598, Tmax = 0.746

  • 7473 measured reflections

  • 1949 independent reflections

  • 1781 reflections with I > 2σ(I)

  • Rint = 0.046
Refinement

  • R[F2 > 2σ(F2)] = 0.038

  • wR(F2) = 0.093

  • S = 1.14

  • 1949 reflections

  • 233 parameters

  • 1 restraint

  • H atoms treated by a mixture of independent and constrained refinement

  • Δρmax = 0.27 e Å−3

  • Δρmin = −0.23 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A D⋯A D—H⋯A
N1—H1N1⋯O3 0.97 (3) 1.86 (3) 2.646 (2) 136 (2)
N2—H1N2⋯O3i 0.90 (3) 2.13 (3) 3.020 (2) 170 (2)
O2—H1O2⋯O3ii 0.89 (3) 1.64 (4) 2.526 (2) 174 (4)
O4—H1O4⋯O3 0.89 (3) 2.45 (3) 2.823 (2) 106 (2)
O4—H1O4⋯O1i 0.89 (3) 1.83 (3) 2.665 (2) 156 (3)
C7—H7⋯O4iii 0.95 2.49 3.197 (3) 132
Symmetry codes: (i) [-x, y+{\script{1\over 2}}, -z]; (ii) [-x, y-{\script{1\over 2}}, -z]; (iii) [-x+1, y-{\script{1\over 2}}, -z].

Data collection: APEX2 (Bruker, 2009[Bruker (2009). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2009[Bruker (2009). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]).

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811031709/hb6347sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536811031709/hb6347Isup2.hkl

checkCIF report


Comment top

Recently, we reported the crystal structure of (E)-2-(2,4-dihydroxybenzylideneammonio)-3-(1H- indol-3-yl)propanoate (Ba-Salamah et al. 2011). In this paper, we report the crystal structure of the title compound, (I), (Fig. 1), obtained by the reaction of L-tryptophan and 2,3-dihydroxybenzaldehyde.

In the zwitterionic title compound, C18H16N2O4, the dihedral angle between the planes of the benzene and indole rings is 26.38 (10)°. Bond lengths have normal values (Allen et al., 1987). The C1 in the benzene ring and C11 in the indol ring are connected together by a chain of four atoms, C7/N1/C8/C10 which has torsion angle 101.2 (2) °. The torsion angles of the chain C8/N1/C7/C1 and N1/C8/C10/C11 are -179.0 (2) ° and 64.4 (2) °, respectively. The title molecule has a zwitterionic form with an intramolecular N1—H1N1···O3 hydrogen bond (Table 1, Fig.1) which generates an S(6) ring motif (Bernstein et al., 1995). The C7—N1 [1.295 (3) Å] and C2—O3[1.318 (3) Å] bond distances are comparable to those [1.3129 (19) and 1.2915 (17) Å; 1.310 (2) and 1.304 (2) Å;1.302 (2) and 1.316 (2) Å] observed in similar zwitterionic structures (Eltayeb et al., 2010a,b,c).

In the crystal structure of (I) as shown in Fig. 2, the molecules are linked through N—H···O, O—H···O and C—H···O hydrogen bonds (Table 1). C—H···π interactions are also present; C8—H8···Cg3i = 2.70 Å, C16—H16···Cg2ii = 2.81 Å. Cg3 and Cg2 are centroids of C12—C17 and C1—C6 rings respectively, [symmetry codes: (i) = –X,-1/2+Y,1-Z; (ii) = –X,1/2+Y,-Z]. The molecules are linked into infinite one-dimensional chains along the b axis.

Related literature top

For a related structure and background to Schiff bases, see: Ba-Salamah et al. (2011). For related structures, see: Eltayeb et al. (2010a,b,c). For reference bond lengths, see: Allen et al. (1987). For graph-set theory, see: Bernstein et al. (1995).

Experimental top

To a 100-ml round-bottom flask were added 20 ml (3:1) methanol-water and 2 mmol of L-tryptophan (0.416 g), the mixture stirred to form a clear colorless solution, 2 mmol of 2,3-dihydroxybenzaldehyde (0.276 g) added to form a yellow clear solution. The mixture was refluxed under heating and stirring for seven hours after which the mixture was filtered and left to stand at room temperature for 12 h. Dark orange crystals which appeared, were filtered after two days and recrystallized from ethanol to yield orange blocks of (I), then left to dry. The IR showed broad peak due to O–H (carboxylic acid and phenol) stretch superimposed on the sharp band due to N–H stretch at 3500–3100 cm-1. The C=O stretch (1708 cm-1), C=N stretch (1644 cm-1), C–O stretch (1230 cm-1), O–H bends (1460 cm-1).

Refinement top

The N- and O-bound H atoms were located in a difference Fourier map and were refined freely. The remaining H atoms were positioned geometrically and refined using a riding model with C–H = 0.95 or 1.00 Å and Uiso(H) = 1.2Ueq(C). In the absence of significant anomalous scattering effects, 1577 Friedel pairs were merged.

Computing details top

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound, with 50% probability ellipsoids for non-H atoms.
[Figure 2] Fig. 2. The crystal packing of title compound, viewed down c axis.
(E)-2-{[1-Carboxy-2-(1H-indol-3-yl)ethyliminio]methyl}-6- hydroxyphenolate top
Crystal data top
C18H16N2O4F(000) = 340
Mr = 324.33Dx = 1.461 Mg m−3
Monoclinic, P21Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ybCell parameters from 1920 reflections
a = 8.4351 (2) Åθ = 3.0–27.7°
b = 9.3038 (3) ŵ = 0.11 mm−1
c = 9.5023 (3) ÅT = 100 K
β = 98.683 (2)°Block, orange
V = 737.18 (4) Å30.32 × 0.22 × 0.20 mm
Z = 2
Data collection top
Bruker SMART APEXII CCD
diffractometer		1949 independent reflections
Radiation source: fine-focus sealed tube1781 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.046
ϕ and ω scansθmax = 28.4°, θmin = 2.2°
Absorption correction: multi-scan
(SADABS; Bruker, 2009)		h = −11→11
Tmin = 0.598, Tmax = 0.746k = −12→12
7473 measured reflectionsl = −12→12
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.038Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.093H atoms treated by a mixture of independent and constrained refinement
S = 1.14 w = 1/[σ2(Fo2) + (0.0454P)2 + 0.0637P]
where P = (Fo2 + 2Fc2)/3
1949 reflections(Δ/σ)max < 0.001
233 parametersΔρmax = 0.27 e Å−3
1 restraintΔρmin = −0.23 e Å−3
Crystal data top
C18H16N2O4V = 737.18 (4) Å3
Mr = 324.33Z = 2
Monoclinic, P21Mo Kα radiation
a = 8.4351 (2) ŵ = 0.11 mm−1
b = 9.3038 (3) ÅT = 100 K
c = 9.5023 (3) Å0.32 × 0.22 × 0.20 mm
β = 98.683 (2)°
Data collection top
Bruker SMART APEXII CCD
diffractometer		1949 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2009)		1781 reflections with I > 2σ(I)
Tmin = 0.598, Tmax = 0.746Rint = 0.046
7473 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0381 restraint
wR(F2) = 0.093H atoms treated by a mixture of independent and constrained refinement
S = 1.14Δρmax = 0.27 e Å−3
1949 reflectionsΔρmin = −0.23 e Å−3
233 parameters
Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O1−0.07419 (19)−0.1334 (2)0.34014 (17)0.0232 (4)
O2−0.0062 (2)−0.1221 (2)0.12218 (17)0.0211 (4)
O30.21206 (18)0.18228 (18)−0.05777 (17)0.0182 (3)
O40.3782 (2)0.2819 (2)−0.27523 (17)0.0208 (4)
N10.2349 (2)0.0546 (2)0.1933 (2)0.0153 (4)
N2−0.1227 (2)0.4135 (2)0.2298 (2)0.0195 (4)
C10.4611 (3)0.1047 (2)0.0751 (2)0.0155 (4)
C20.3695 (3)0.1726 (2)−0.0437 (2)0.0170 (5)
C30.4555 (3)0.2223 (3)−0.1530 (2)0.0171 (5)
C40.6201 (3)0.2052 (3)−0.1389 (3)0.0197 (5)
H40.67480.2395−0.21260.024*
C50.7084 (3)0.1396 (3)−0.0203 (3)0.0201 (5)
H50.82160.1306−0.01290.024*
C60.6296 (3)0.0881 (3)0.0856 (3)0.0189 (5)
H60.68810.04130.16590.023*
C70.3873 (3)0.0479 (3)0.1886 (2)0.0159 (4)
H70.45390.00240.26530.019*
C80.1609 (3)−0.0021 (3)0.3116 (2)0.0155 (4)
H80.2412−0.06730.36750.019*
C90.0139 (3)−0.0931 (3)0.2577 (2)0.0163 (5)
C100.1237 (3)0.1170 (3)0.4127 (2)0.0170 (4)
H10A0.08510.07220.49570.020*
H10B0.22450.16860.44820.020*
C110.0013 (3)0.2246 (3)0.3481 (2)0.0172 (5)
C12−0.1594 (3)0.2345 (3)0.3819 (2)0.0158 (4)
C13−0.2460 (3)0.1543 (3)0.4697 (2)0.0182 (5)
H13−0.19910.07320.52080.022*
C14−0.4016 (3)0.1962 (3)0.4803 (3)0.0200 (5)
H14−0.46190.14270.53890.024*
C15−0.4712 (3)0.3162 (3)0.4059 (3)0.0227 (5)
H15−0.57720.34370.41670.027*
C16−0.3889 (3)0.3954 (3)0.3172 (3)0.0205 (5)
H16−0.43730.47540.26540.025*
C17−0.2323 (3)0.3536 (3)0.3065 (2)0.0176 (5)
C180.0167 (3)0.3350 (3)0.2562 (2)0.0189 (5)
H180.11090.35480.21600.023*
H1N10.171 (3)0.093 (4)0.108 (3)0.034 (8)*
H1N2−0.141 (3)0.490 (4)0.171 (3)0.024 (7)*
H1O2−0.084 (4)−0.187 (4)0.102 (3)0.033 (8)*
H1O40.273 (4)0.292 (4)−0.278 (3)0.046 (10)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0195 (8)0.0321 (10)0.0189 (8)−0.0065 (7)0.0056 (6)0.0020 (8)
O20.0196 (8)0.0255 (10)0.0191 (8)−0.0075 (7)0.0058 (6)−0.0043 (7)
O30.0124 (7)0.0216 (8)0.0210 (8)0.0019 (6)0.0043 (6)0.0020 (7)
O40.0162 (8)0.0266 (9)0.0208 (8)0.0010 (7)0.0069 (7)0.0035 (7)
N10.0142 (9)0.0166 (9)0.0157 (9)0.0013 (7)0.0039 (7)0.0001 (8)
N20.0194 (10)0.0179 (10)0.0228 (10)0.0010 (8)0.0087 (8)0.0028 (9)
C10.0137 (10)0.0168 (11)0.0166 (10)−0.0014 (8)0.0039 (8)−0.0031 (9)
C20.0143 (10)0.0162 (11)0.0208 (11)0.0007 (8)0.0041 (8)−0.0019 (9)
C30.0169 (10)0.0152 (11)0.0197 (11)−0.0008 (9)0.0047 (8)−0.0017 (9)
C40.0170 (11)0.0221 (13)0.0218 (11)−0.0026 (9)0.0086 (9)−0.0004 (10)
C50.0121 (10)0.0234 (12)0.0250 (11)−0.0021 (9)0.0037 (9)−0.0021 (10)
C60.0146 (10)0.0225 (12)0.0191 (11)−0.0006 (9)0.0012 (8)0.0003 (10)
C70.0159 (10)0.0144 (10)0.0169 (10)−0.0006 (8)0.0006 (8)−0.0024 (9)
C80.0136 (10)0.0182 (11)0.0149 (10)0.0002 (9)0.0028 (8)0.0010 (9)
C90.0122 (10)0.0162 (11)0.0203 (11)0.0004 (8)0.0022 (8)0.0021 (9)
C100.0150 (10)0.0200 (12)0.0165 (10)0.0012 (9)0.0040 (8)−0.0001 (9)
C110.0166 (10)0.0182 (11)0.0170 (10)−0.0010 (9)0.0032 (8)−0.0026 (9)
C120.0150 (10)0.0177 (11)0.0152 (10)−0.0004 (9)0.0043 (8)−0.0036 (9)
C130.0195 (11)0.0182 (12)0.0171 (10)0.0007 (9)0.0038 (8)−0.0011 (9)
C140.0181 (11)0.0202 (12)0.0230 (11)−0.0031 (9)0.0080 (9)−0.0011 (10)
C150.0166 (11)0.0228 (13)0.0300 (13)−0.0003 (9)0.0074 (9)−0.0049 (11)
C160.0188 (11)0.0161 (11)0.0272 (12)0.0033 (8)0.0054 (9)−0.0002 (10)
C170.0182 (11)0.0168 (11)0.0189 (11)−0.0017 (9)0.0065 (8)−0.0021 (9)
C180.0166 (11)0.0207 (12)0.0200 (11)−0.0007 (9)0.0048 (9)−0.0036 (10)
Geometric parameters (Å, º) top
O1—C91.218 (3)C6—H60.9500
O2—C91.301 (3)C7—H70.9500
O2—H1O20.89 (3)C8—C91.525 (3)
O3—C21.318 (3)C8—C101.530 (3)
O4—C31.361 (3)C8—H81.0000
O4—H1O40.89 (3)C10—C111.501 (3)
N1—C71.295 (3)C10—H10A0.9900
N1—C81.465 (3)C10—H10B0.9900
N1—H1N10.97 (3)C11—C181.367 (4)
N2—C181.375 (3)C11—C121.442 (3)
N2—C171.378 (3)C12—C131.405 (3)
N2—H1N20.90 (3)C12—C171.409 (3)
C1—C21.417 (3)C13—C141.387 (3)
C1—C61.419 (3)C13—H130.9500
C1—C71.426 (3)C14—C151.403 (4)
C2—C31.429 (3)C14—H140.9500
C3—C41.384 (3)C15—C161.382 (4)
C4—C51.395 (3)C15—H150.9500
C4—H40.9500C16—C171.396 (3)
C5—C61.373 (3)C16—H160.9500
C5—H50.9500C18—H180.9500
C9—O2—H1O2110 (2)C10—C8—H8107.0
C3—O4—H1O4115 (2)O1—C9—O2124.9 (2)
C7—N1—C8123.31 (19)O1—C9—C8119.9 (2)
C7—N1—H1N1115.0 (18)O2—C9—C8115.22 (19)
C8—N1—H1N1121.5 (18)C11—C10—C8114.84 (18)
C18—N2—C17108.2 (2)C11—C10—H10A108.6
C18—N2—H1N2126.3 (17)C8—C10—H10A108.6
C17—N2—H1N2125.5 (17)C11—C10—H10B108.6
C2—C1—C6121.6 (2)C8—C10—H10B108.6
C2—C1—C7121.40 (19)H10A—C10—H10B107.5
C6—C1—C7117.0 (2)C18—C11—C12106.1 (2)
O3—C2—C1122.1 (2)C18—C11—C10129.5 (2)
O3—C2—C3121.2 (2)C12—C11—C10124.3 (2)
C1—C2—C3116.62 (19)C13—C12—C17119.6 (2)
O4—C3—C4118.2 (2)C13—C12—C11133.6 (2)
O4—C3—C2121.44 (19)C17—C12—C11106.9 (2)
C4—C3—C2120.3 (2)C14—C13—C12118.5 (2)
C3—C4—C5122.3 (2)C14—C13—H13120.8
C3—C4—H4118.9C12—C13—H13120.8
C5—C4—H4118.9C13—C14—C15121.1 (2)
C6—C5—C4119.1 (2)C13—C14—H14119.5
C6—C5—H5120.4C15—C14—H14119.5
C4—C5—H5120.4C16—C15—C14121.4 (2)
C5—C6—C1120.1 (2)C16—C15—H15119.3
C5—C6—H6119.9C14—C15—H15119.3
C1—C6—H6119.9C15—C16—C17117.7 (2)
N1—C7—C1123.8 (2)C15—C16—H16121.2
N1—C7—H7118.1C17—C16—H16121.2
C1—C7—H7118.1N2—C17—C16130.1 (2)
N1—C8—C9111.15 (18)N2—C17—C12108.1 (2)
N1—C8—C10111.87 (19)C16—C17—C12121.8 (2)
C9—C8—C10112.33 (18)C11—C18—N2110.8 (2)
N1—C8—H8107.0C11—C18—H18124.6
C9—C8—H8107.0N2—C18—H18124.6
C6—C1—C2—O3176.6 (2)C9—C8—C10—C11−61.5 (3)
C7—C1—C2—O3−2.4 (3)C8—C10—C11—C18−75.8 (3)
C6—C1—C2—C30.5 (3)C8—C10—C11—C12108.5 (3)
C7—C1—C2—C3−178.4 (2)C18—C11—C12—C13−179.4 (2)
O3—C2—C3—O40.3 (3)C10—C11—C12—C13−2.8 (4)
C1—C2—C3—O4176.4 (2)C18—C11—C12—C17−0.2 (2)
O3—C2—C3—C4−177.1 (2)C10—C11—C12—C17176.4 (2)
C1—C2—C3—C4−1.0 (3)C17—C12—C13—C14−0.5 (3)
O4—C3—C4—C5−177.2 (2)C11—C12—C13—C14178.6 (2)
C2—C3—C4—C50.3 (4)C12—C13—C14—C15−0.3 (3)
C3—C4—C5—C60.9 (4)C13—C14—C15—C161.3 (4)
C4—C5—C6—C1−1.3 (4)C14—C15—C16—C17−1.3 (4)
C2—C1—C6—C50.6 (4)C18—N2—C17—C16178.8 (2)
C7—C1—C6—C5179.6 (2)C18—N2—C17—C12−0.3 (3)
C8—N1—C7—C1−179.0 (2)C15—C16—C17—N2−178.5 (2)
C2—C1—C7—N1−0.7 (4)C15—C16—C17—C120.5 (4)
C6—C1—C7—N1−179.7 (2)C13—C12—C17—N2179.6 (2)
C7—N1—C8—C9−132.3 (2)C11—C12—C17—N20.3 (2)
C7—N1—C8—C10101.2 (2)C13—C12—C17—C160.4 (3)
N1—C8—C9—O1−170.5 (2)C11—C12—C17—C16−178.9 (2)
C10—C8—C9—O1−44.3 (3)C12—C11—C18—N20.0 (3)
N1—C8—C9—O29.7 (3)C10—C11—C18—N2−176.3 (2)
C10—C8—C9—O2135.9 (2)C17—N2—C18—C110.2 (3)
N1—C8—C10—C1164.4 (2)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1N1···O30.97 (3)1.86 (3)2.646 (2)136 (2)
N2—H1N2···O3i0.90 (3)2.13 (3)3.020 (2)170 (2)
O2—H1O2···O3ii0.89 (3)1.64 (4)2.526 (2)174 (4)
O4—H1O4···O30.89 (3)2.45 (3)2.823 (2)106 (2)
O4—H1O4···O1i0.89 (3)1.83 (3)2.665 (2)156 (3)
C7—H7···O4iii0.952.493.197 (3)132
Symmetry codes: (i) −x, y+1/2, −z; (ii) −x, y−1/2, −z; (iii) −x+1, y−1/2, −z.

Experimental details

Crystal data
Chemical formulaC18H16N2O4
Mr324.33
Crystal system, space groupMonoclinic, P21
Temperature (K)100
a, b, c (Å)8.4351 (2), 9.3038 (3), 9.5023 (3)
β (°) 98.683 (2)
V (Å3)737.18 (4)
Z2
Radiation typeMo Kα
µ (mm−1)0.11
Crystal size (mm)0.32 × 0.22 × 0.20
Data collection
DiffractometerBruker SMART APEXII CCD
diffractometer
Absorption correctionMulti-scan
(SADABS; Bruker, 2009)
Tmin, Tmax0.598, 0.746
No. of measured, independent and
observed [I > 2σ(I)] reflections		7473, 1949, 1781
Rint0.046
(sin θ/λ)max (Å−1)0.668
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.038, 0.093, 1.14
No. of reflections1949
No. of parameters233
No. of restraints1
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3)0.27, −0.23

Computer programs: APEX2 (Bruker, 2009), SAINT (Bruker, 2009), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1N1···O30.97 (3)1.86 (3)2.646 (2)136 (2)
N2—H1N2···O3i0.90 (3)2.13 (3)3.020 (2)170 (2)
O2—H1O2···O3ii0.89 (3)1.64 (4)2.526 (2)174 (4)
O4—H1O4···O30.89 (3)2.45 (3)2.823 (2)106 (2)
O4—H1O4···O1i0.89 (3)1.83 (3)2.665 (2)156 (3)
C7—H7···O4iii0.952.493.197 (3)132
Symmetry codes: (i) −x, y+1/2, −z; (ii) −x, y−1/2, −z; (iii) −x+1, y−1/2, −z.
 

Acknowledgements

The authors thank the Malaysian Government and Universiti Sains Malaysia for the RU research grant (1001/PKIMIA/815067). NEE thanks Universiti Sains Malaysia for a post-doctoral fellowship and the Inter­national University of Africa (Sudan) for providing study leave. SAB thanks the Ministry of Higher Education and Scientific Research (Yemen) for a scholarship.

References

First citationAllen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–19.  CrossRef Web of Science Google Scholar
 First citationBa-Salamah, S. A., Eltayeb, N. E., Teoh, S. G. & Lo, K. M. (2011). Acta Cryst. E67, o2113–o2114.  CrossRef IUCr Journals Google Scholar
 First citationBernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555–1573.  CrossRef CAS Web of Science Google Scholar
 First citationBruker (2009). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
 First citationEltayeb, N. E., Teoh, S. G., Chantrapromma, S. & Fun, H.-K. (2010a). Acta Cryst. E66, o934–o935.  Web of Science CSD CrossRef IUCr Journals Google Scholar
 First citationEltayeb, N. E., Teoh, S. G., Fun, H.-K. & Chantrapromma, S. (2010b). Acta Cryst. E66, o1262–o1263.  Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
 First citationEltayeb, N. E., Teoh, S. G., Fun, H.-K. & Chantrapromma, S. (2010c). Acta Cryst. E66, o1536–o1537.  CrossRef IUCr Journals Google Scholar
 First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
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ISSN: 2056-9890
Volume 67| Part 9| September 2011| Page o2389
doi:10.1107/S1600536811031709
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