Crystal structure of l-tryptophan–fumaric acid–water (1/1/1)

M Lydia Caroline; S Kumaresan; P G Aravindan; M Peer Mohamed; G Mani

doi:10.1107/S205698901501484X

. 2015 Aug 15;71(Pt 9):o661–o662. doi: 10.1107/S205698901501484X

Crystal structure of l-tryptophan–fumaric acid–water (1/1/1)

M Lydia Caroline ^a,^*, S Kumaresan ^a, P G Aravindan ^b, M Peer Mohamed ^c, G Mani ^a

PMCID: PMC4555439 PMID: 26396891

Abstract

In the title compound, C₁₁H₁₂N₂O₂·C₄H₄O₄·H₂O, the l-tryptophan molecule crystallized as a zwitterion, together with a neutral fumaric acid molecule and a water solvent molecule. In the crystal, the three components are linked by a series of N—H⋯O, O—H⋯O and C—H⋯O hydrogen bonds, forming slabs lying parallel to (001). The slabs are connected by O—H⋯O hydrogen bonds, involving inversion-related fumaric acid groups, leading to the formation of a three-dimensional structure.

Keywords: crystal structure, l-tryptophan, fumaric acid, hydrogen bonding, three-dimensional structure

Related literature

For literature on the UV spectroscopy of proteins, see: Demchenko (1986 ▸). For the different polymorphic forms of fumaric acid, see: Reis & Schneider (1928 ▸); Yardley (1925 ▸); Bednowitz & Post (1966 ▸). For the nonlinear optical properties of organic molecules, see: Chemla & Zyss (1987 ▸); Zyss & Ledoux (1994 ▸); Zyss & Nicoud (1996 ▸). For the common conformations of l-tryptophan, see: Bye et al. (1973 ▸); Bakke & Mostad (1980 ▸). The bond lengths and angles in l-trypophan, see, for example: Gorbitz (2006 ▸); Gorbitz et al. (2012 ▸), and for fumaric acid, see: Goswami et al. (1999 ▸). For the crystal structure of l-tryptophan formic acid solvate, see: Hubschle et al. (2002 ▸). For details of the Cambridge Structural Database, see: Groom & Allen (2014 ▸). graphic file with name e-71-0o661-scheme1.jpg

Experimental

Crystal data

C₁₁H₁₂N₂O₂·C₄H₄O₄·H₂O
M _r = 338.31
Monoclinic,
a = 11.3928 (8) Å
b = 6.6476 (4) Å
c = 21.4219 (13) Å
β = 95.801 (3)°
V = 1614.07 (18) Å³
Z = 4
Mo Kα radiation
μ = 0.11 mm⁻¹
T = 296 K
0.30 × 0.20 × 0.20 mm

Data collection

Bruker Kappa APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2004 ▸) T _min = 0.898, T _max = 0.978
10737 measured reflections
3157 independent reflections
2731 reflections with I > 2σ(I)
R _int = 0.025

Refinement

R[F ² > 2σ(F ²)] = 0.034
wR(F ²) = 0.084
S = 1.04
3157 reflections
242 parameters
4 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.18 e Å⁻³
Δρ_min = −0.15 e Å⁻³

Data collection: APEX2 (Bruker, 2004 ▸); cell refinement: APEX2 and SAINT (Bruker, 2004 ▸); data reduction: SAINT and XPREP (Bruker, 2004 ▸); program(s) used to solve structure: SIR92 (Altomare et al., 1994 ▸); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015 ▸); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012 ▸) and Mercury (Macrae et al., 2008 ▸); software used to prepare material for publication: SHELXL2014 and PLATON (Spek, 2009 ▸).

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S205698901501484X/su5176sup1.cif

e-71-0o661-sup1.cif^{(372.7KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S205698901501484X/su5176Isup2.hkl

e-71-0o661-Isup2.hkl^{(252.3KB, hkl)}

Click here for additional data file.^{(6.2KB, cml)}

Supporting information file. DOI: 10.1107/S205698901501484X/su5176Isup3.cml

Click here for additional data file.^{(1MB, tif)}

. DOI: 10.1107/S205698901501484X/su5176fig1.tif

The molecular structure of the title compound, with atom labelling. Displacement ellipsoids are drawn at the 40% probability level.

Click here for additional data file.^{(3MB, tif)}

a . DOI: 10.1107/S205698901501484X/su5176fig2.tif

The crystal packing of the title compound, viewed along the a axis. The hydrogen bonds are shown as dashed lines (see Table 1 for details).

Click here for additional data file.^{(2.9MB, tif)}

b . DOI: 10.1107/S205698901501484X/su5176fig3.tif

The crystal packing of the title compound, viewed along the b axis. The hydrogen bonds are shown as dashed lines (see Table 1 for details).

CCDC reference: 1417535

Additional supporting information: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (, ).

DHA	DH	HA	D A	DHA
N1H1O3ⁱ	0.85(3)	2.11(3)	2.912(3)	158(3)
N2H2AO7	0.92(4)	1.94(4)	2.845(3)	170(3)
N2H2BO1ⁱⁱ	0.94(3)	2.30(3)	3.085(3)	140(2)
N2H2BO3	0.94(3)	2.28(3)	2.901(3)	123(2)
N2H2CO2ⁱⁱⁱ	0.96(3)	1.87(3)	2.832(3)	174(3)
O4H4OO1ⁱⁱ	0.82	1.74	2.559(2)	178
O5H5OO6^iv	0.82	1.81	2.630(3)	174
O7H7AO1^v	0.88(2)	2.60(3)	3.261(3)	133(3)
O7H7AO2^v	0.88(2)	1.97(2)	2.824(3)	165(3)
O7H7BO2^vi	0.85(2)	2.53(3)	3.347(3)	162(3)
C3H3BO3^vii	0.97	2.66	3.255(3)	120
C5H5O7ⁱ	0.93	2.58	3.491(3)	166

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) ; (v) ; (vi) ; (vii) .

Acknowledgments

The scientific support extended by the Sophisticated Analytical Instruments Facility, Indian Institute of Technology IITM, Chennai, in solving the crystal structure is greatly appreciated. The authors personally thank Professor E. M. Subramanian, retired Professor of Chemistry, Pachayappas College, Kanchipuram, Tamilnadu, for valuable suggestions.

supplementary crystallographic information

S1. Comment

Natural aromatic amino acids, particularly tryptophan, have near UV absorption and emission properties which are utilized extensively in solution phase investigations of structure-function relationships (Demchenko, 1986). Fumaric acid is known to exist in two different polymorphic forms viz. cis and trans ( Reis & Schneider, 1928; Yardley, 1925; Bednowitz & Post, 1966).

In conjunction with our ongoing work on non-linear optical organic crystals among the 20 naturally occurring amino acids, we have directed our interest to tryptophan (Trp), one of the essential amino acids for humans. The non-linear optical properties of organic molecules and crystals have been reviewed by Zyss (Chemla & Zyss, 1987; Zyss & Ledoux, 1994; Zyss & Nicoud, 1996). For similar properties and most the common confirmations of L-tryptophan have been reported (Bye et al., 1973; Bakke & Mostad, 1980). Compared with other amino acids, there are less than 30 tryptophan structures listed in the Cambridge Structural Database (Groom & Allen, 2014), due to the difficulty of obtaining good optical quality crystals; as noted by (Hubschle et al., 2002) who studied the crystal structure of L-tryptophan formic acid solvate. We successfully obtained good quality hard golden-yellow single crystals of L-tryptophan fumaric acid monohydrate, and we report herein on its synthesis and crystal structure.

In the title compound, Fig. 1, L-tryptophan is zwitterionic, as are most amino acids in the solid state, and fumaric acid is neutral. The bond lengths and angles in L-trypophan and fumaric acid are similar to those reported previously (Gorbitz, 2006; Gorbitz et al., 2012; Goswami et al., 1999).

In the crystal, the three components are linked by a series of O—H···O, N—H···O and C—H···O hydrogen bonds forming slabs lying parallel to (001); Table 1 and Fig. 2. The slabs are connected by O—H···O hydrogen bonds, involving inversion related fumaric acid groups, leading to the formation of a three-dimensional structure; Table 1 and Fig. 3.

S2. Synthesis and crystallization

An aqueous solution of L-tryptophan and fumaric acid in a 1:1 stoichiometric ratio was stirred at room temperature for 6 h. The resulting yellow solution was filtered and kept in a Petri dish. Yellow prismatic-shaped hard crystals suitable for X-ray analysis were obtained over a period of 5 days.

S3. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. The N-bound, acid and water H atoms were located in a difference Fourier map. The NH and NH₃ H atoms were freely refined. The water H atoms were refined with distance restraints: O—H = 0.86 (2) Å, H···H = 1.388 (20) Å with U_iso(H) = 1.5U_eq(O). The acid (OH) H atoms and the C-bound H atoms were included in calculated positions and treated as riding atoms: U_iso(H) = 1.5U_eq(O,C) for OH and methyl H atoms and 1.2U_eq(C) for other H atoms.