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Acta Cryst.(2002). E58, o279±o281 DOI: 10.1107/S1600536802002751 K. Rajagopalet al. C5H12NO2+C2Cl3O2ÿ

o279

organic papers

Acta Crystallographica Section E

Structure Reports

Online

ISSN 1600-5368

DL

-Valinium trichloroacetate at 123 K

K. Rajagopal,aR. V.

Krishnakumar,bM. Subha

Nandhini,cA. Mostadd and

S. Natarajanc*

aDepartment of Physics, Saraswathi Narayanan College, Madurai 625 022, India,bDepartment of Physics, Thiagarajar College, Madurai 625 009, India,cDepartment of Physics, Madurai Kamaraj University, Madurai 625 021, India, anddDepartment of Chemistry, University of Oslo, PO Box 1033 Blindern, N-0315 Oslo 3, Norway

Correspondence e-mail: [email protected]

Key indicators Single-crystal X-ray study T= 123 K

Mean(C±C) = 0.002 AÊ Rfactor = 0.033 wRfactor = 0.083

Data-to-parameter ratio = 19.2

For details of how these key indicators were automatically derived from the article, see http://journals.iucr.org/e.

#2002 International Union of Crystallography Printed in Great Britain ± all rights reserved

In the title compound, C5H12NO2+C2Cl3O2ÿ, the valine

molecule is in a cationic state and the trichloroacetic acid is in the anionic state. In the crystal, the intermolecular NÐ H O and OÐH O hydrogen bonds link the molecules to form an in®nite two-dimensional network parallel to (001).

Comment

In our laboratory, we have been elucidating the crystal structures of proton-transfer complexes of the type A.B, whereAis an amino acid andBis a carboxylic acid which is believed to have existed in the pre-biotic earth (Miller & Orgel, 1974; Kvenvoldenet al., 1971). A brief survey of the Cambridge Structural Database (Allen & Kennard, 1993) revealed a scarcity of precise crystallographic data on amino acid±halogenoacetic acid complexes. We report here the crystal structure of a complex ofdl-valine with trichloroacetic acid, namely, dl-valinium trichloroacetate, (I). Systematic X-ray investigations of such compounds are expected to throw light on the importance of halogen±halogen interactions on biomolecular aggregation patterns. The crystal structure of a complex of a dipeptide with trichloroacetic acid, l -phenyl-alanylglycine trichloroacetate has already been reported (Mitra & Subramanian, 1993). The crystal structure of tri-chloroacetic acid remains unknown.

In (I), the valine molecule is in a cationic state with a positively charged amino group and an uncharged carboxylic acid group. The trichloroacetic acid exists in the anionic state with a negatively charged carboxylate group (Fig. 1). The carboxylate group of valine is planar, and the amino N atom deviates from this plane by 0.528 (1) AÊ, leading to the twisting of the CÐN bond out of the plane of the carboxyl group by 21.9 (1). The conformation of the valine molecule,

deter-mined by the internal rotation angles 2 [ÿ22.4 (2)], 11

[ÿ162.9 (1)] and 12 [70.9 (1)], agrees well with the values

observed for the monoclinic form ofdl-valine (Mallikarjunan & Rao, 1969) and for the triclinic form ofdl-valine (Dalhus &

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organic papers

o280

K. Rajagopalet al. C5H12NO2+C2Cl3O2ÿ Acta Cryst.(2002). E58, o279±o281

GoÈrbitz, 1996). However, in dl-valinium maleate (Alagar et al., 2001), 11 [57.1 (2)] deviates signi®cantly from that

observed in the present study. In the crystal, the valine and the trichloroacetic acid molecules are alternately linked by OÐ H O and NÐH O hydrogen bonds to form in®nite one-dimensional chains along [110]. The inversion-related chains are interlinked by NÐH O hydrogen bonds to form an in®nite two-dimensional network parallel to (001). In this network, the d and l isomers exist as centrosymmetrically hydrogen-bonded dimers (Table 2).

Experimental

Single crystals of (I) were grown from a saturated aqueous solution containing dl-valine and trichloroacetic acid in the stoichiometric ratio 1:1.

Crystal data

C5H12NO2+C2Cl3O2ÿ

Mr= 280.53 Triclinic,P1

a= 7.2380 (14) AÊ

b= 8.4150 (17) AÊ

c= 10.303 (2) AÊ = 106.50 (3) = 97.50 (3) = 95.80 (3) V= 590.2 (2) AÊ3

Z= 2

Dx= 1.578 Mg mÿ3

Dm= 1.60 Mg mÿ3

Dmmeasured by ¯otation in bromoform and xylene MoKradiation Cell parameters from 1024

re¯ections = 2.5±23.0 = 0.77 mmÿ1

T= 123 (2) K Prismatic, colourless 0.500.400.15 mm

Data collection

Bruker SMART CCD diffractometer !scans

Absorption correction: multi-scan (SADABS; Bruker, 1998)

Tmin= 0.68,Tmax= 0.89 7923 measured re¯ections

3537 independent re¯ections 3204 re¯ections withI> 2(I)

Rint= 0.019 max= 30.7

h=ÿ9!10

k=ÿ11!12

l=ÿ14!14

Re®nement

Re®nement onF2

R[F2> 2(F2)] = 0.033

wR(F2) = 0.083

S= 1.04 3537 re¯ections 184 parameters

All H-atom parameters re®ned

w= 1/[2(F

o2) + (0.0346P)2 + 0.3602P]

whereP= (Fo2+ 2Fc2)/3 (/)max< 0.001

max= 0.61 e AÊÿ3

min=ÿ0.59 e AÊÿ3

Table 1

Selected geometric parameters (AÊ,).

Cl1ÐC7 1.7747 (14)

Cl2ÐC7 1.7580 (14)

Cl3ÐC7 1.7749 (17)

O1ÐC1 1.3150 (16)

O2ÐC1 1.2136 (17)

O3ÐC6 1.2538 (15)

O4ÐC6 1.2300 (15)

NÐC2 1.4953 (17)

C1ÐC2 1.5197 (17)

C2ÐC3 1.5320 (19)

C3ÐC5 1.525 (2)

C3ÐC4 1.531 (2)

C6ÐC7 1.5578 (18)

O2ÐC1ÐO1 125.57 (11)

O2ÐC1ÐC2 122.27 (11)

O1ÐC1ÐC2 112.15 (11)

NÐC2ÐC1 107.11 (11)

NÐC2ÐC3 111.25 (10)

C1ÐC2ÐC3 112.46 (10)

C5ÐC3ÐC4 111.94 (15)

C5ÐC3ÐC2 112.10 (11)

C4ÐC3ÐC2 111.28 (13)

O4ÐC6ÐO3 127.11 (12)

O4ÐC6ÐC7 117.64 (11)

O3ÐC6ÐC7 115.22 (11)

C6ÐC7ÐCl2 112.03 (9)

C6ÐC7ÐCl1 111.82 (9)

Cl2ÐC7ÐCl1 108.40 (8)

C6ÐC7ÐCl3 105.78 (9)

Cl2ÐC7ÐCl3 109.62 (8)

Cl1ÐC7ÐCl3 109.13 (8)

Table 2

Hydrogen-bonding geometry (AÊ,).

DÐH A DÐH H A D A DÐH A

O1ÐH10 O3 0.89 (3) 1.72 (3) 2.601 (2) 169 (2) NÐH2N O4i 0.84 (2) 1.93 (2) 2.761 (2) 169.6 (19) NÐH1N O3ii 0.89 (2) 1.94 (2) 2.804 (2) 163.6 (19) NÐH3N O2iii 0.90 (2) 2.00 (2) 2.871 (2) 162.5 (17) Symmetry codes: (i)xÿ1;yÿ1;z; (ii) 1ÿx;1ÿy;2ÿz; (iii)ÿx;1ÿy;2ÿz.

All the H atoms were located from a difference Fourier map and were included in the re®nement with isotropic displacement para-meters. The ranges of CÐH and NÐH bond lengths are 0.96 (3)± 0.98 (2) AÊ and 0.84 (2)±0.90 (2) AÊ, respectively, and the OÐH distance is 0.89 (3) AÊ.

Figure 2

Packing of the molecules of (I), viewed down theaaxis.

Figure 1

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Data collection: SMART-NT (Bruker, 1999); cell re®nement:

SMART-NT; data reduction:SAINT-NT(Bruker, 1999); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to re®ne structure: SHELXL97 (Sheldrick, 1997); molecular graphics:PLATON(Spek, 1999); software used to prepare material for publication:SHELXL97.

KR thanks the UGC for the FIP programme. SN and KR also thank the UGC for the DRS programme and the Bio-informatics Centre, Madurai Kamaraj University, for providing the Cambridge Structural Database (Allen & Kennard, 1993).

References

Alagar, M., Krishnakumar, R. V., Mostad, A. & Natarajan, S. (2001).Acta Cryst.E57, o1102±o1104.

Allen, F. H. & Kennard, O. (1993).Chem. Des. Autom. News.8, 1, 31±37. Bruker. (1998).SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Bruker. (1999).SMART-NTand SAINT-NT. Bruker AXS Inc., Madison,

Wisconsin, USA.

Dalhus, B. & GoÈrbitz, C. H. (1996).Acta Cryst.C52, 1759±1761.

Kvenvolden, K. A., Lawless, J. G. & Ponnamperuma, C. (1971).Proc. Natl Acad. Sci. USA,68, 486±490.

Mallikarjunan, M. & Rao, S. T. (1969).Acta Cryst.B25, 296±303.

Miller, S. L. & Orgel, E. L. (1974).The Origins of Life on The Earth, p. 83. New Jersey: Prentice-Hall.

Mitra, S. N. & Subramanian, E. (1993).Curr. Sci.65, 980±983. Sheldrick, G. M. (1990).Acta Cryst.A46, 467±473.

Sheldrick, G. M. (1997).SHELXL97. University of GoÈttingen, Germany. Spek, A. L. (1999). PLATON for Windows, Utrecht University, The

Netherlands.

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supporting information

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Acta Cryst. (2002). E58, o279–o281

supporting information

Acta Cryst. (2002). E58, o279–o281 [doi:10.1107/S1600536802002751]

DL

-Valinium trichloroacetate at 123

K

K. Rajagopal, R. V. Krishnakumar, M. Subha Nandhini, A. Mostad and S. Natarajan

S1. Comment

In our laboratory, we have been elucidating the crystal structures of proton-transfer complexes of the type A·B, where A

is a amino acid and B is a carboxylic acid which is believed to have existed in the pre-biotic earth (Miller & Orgel, 1974;

Kvenvolden et al., 1971). A brief survey on the Cambridge structural Database Database (Allen & Kennard, 1993)

revealed scarcity of precise crystallographic data on amino acid–halogeno acetic acid complexes. We report here, the

crystal structure of a complex of DL-valine with trichloroacetic acid, namely, DL-valinium trichloroacetate, (I).

Systematic X-ray investigation, on such compounds are expected to throw light on the importance of halogen–halogen

interactions on biomolecular aggregation patterns. The crystal structure of a complex of a dipeptide with trichloroacetic

acid, L-phenylalanylglycine trichloroaceteate is already reported (Mitra & Subramanian, 1993). The crystal structure of

trichloroacetic acid still remains unknown.

In (I), the valine molecule is in a cationic state with a positively charged amino group and an uncharged carboxylic acid

group. The trichloroacetic acid exists in the anionic state with a negatively charged carboxylate group (Fig. 1). The

carboxylate group of valine is planar and the amino nitrogen deviates from this plane by 0.528 (1) Å leading to the

twisting of the C—N bond out of the plane of the carboxyl group by 21.9 (1)°. The conformation of the valine molecule

determined by the internal rotation angles ψ2 [-22.4 (2)], χ11 [-162.9 (1)] and χ12 [70.9 (1)°] agree well with the values

observed for the monoclinic form of DL-valine (Mallikarjunan & Rao, 1969) and for the triclinic form of DL-valine

(Dalhus & Görbitz, 1996). However, in DL-valinium maleate (Alagar et al., 2001), χ11 [57.1 (2)°] deviates siginificantly

from that observed in the present study. In the crystal, the valine and the trichloroacetic acid molecules are alteratively

linked by O—H···O and N—H···O hydrogen bonds to form infinte one-dimensional chains along [110]. The inversion

related chains are interlinked by N—H···O hydrogen bonds to form infinite two-dimensional network parallel to (001). In

this network, the D and L isomers exist as centrosymmetrically hydrogen-bonded dimers (Table 2).

S2. Experimental

Single crystals of (I) were grown from a saturated aqueous solution containing DL-valine and trichloroacetic acid in

stoichiometric ratio.

S3. Refinement

All the H atoms were located from a difference Fourier map and were included in the refinement with isotropic

displacement parameters. The range of C—H and N—H bond lengths are 0.96 (3)–0.98 (2) Å and 0.84 (2)–0.90 (2) Å,

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[image:5.610.123.482.68.321.2]

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Acta Cryst. (2002). E58, o279–o281

Figure 1

The molecular structure of (I) with the atom-numbering scheme and 50% probability displacement ellipsoids.

Figure 2

[image:5.610.124.488.358.670.2]
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supporting information

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Acta Cryst. (2002). E58, o279–o281

DL-valinium trichloroacetate

Crystal data

C5H12NO2+·C2Cl3O2−

Mr = 280.53 Triclinic, P1 Hall symbol: -P 1 a = 7.2380 (14) Å b = 8.4150 (17) Å c = 10.303 (2) Å α = 106.50 (3)° β = 97.50 (3)° γ = 95.80 (3)° V = 590.2 (2) Å3

Z = 2

F(000) = 288 Dx = 1.578 Mg m−3

Dm = 1.60 Mg m−3

Dm measured by floatation in bromoform and xylene

Mo radiation, λ = 0.71073 Å Cell parameters from 1024 reflections θ = 2.5–23.0°

µ = 0.77 mm−1

T = 123 K

Prismatic, colourless 0.50 × 0.40 × 0.15 mm

Data collection

Bruker SMART CCD diffractometer

Radiation source: fine-focus sealed tube Graphite monochromator

Detector resolution: 8 pixels mm-1

ω scans

Absorption correction: empirical (using intensity measurements)

(SADABS; Bruker, 1998)

Tmin = 0.68, Tmax = 0.89 7923 measured reflections 3537 independent reflections 3204 reflections with I > 2σ(I) Rint = 0.019

θmax = 30.7°, θmin = 2.6°

h = −9→10 k = −11→12 l = −14→14

Refinement

Refinement on F2 Least-squares matrix: full R[F2 > 2σ(F2)] = 0.033

wR(F2) = 0.083

S = 1.04 3537 reflections 184 parameters 0 restraints

Primary atom site location: structure-invariant direct methods

Secondary atom site location: difference Fourier map

Hydrogen site location: inferred from neighbouring sites

All H-atom parameters refined w = 1/[σ2(F

o2) + (0.0346P)2 + 0.3602P] where P = (Fo2 + 2Fc2)/3

(Δ/σ)max < 0.001 Δρmax = 0.61 e Å−3 Δρmin = −0.59 e Å−3

Special details

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)

x y z Uiso*/Ueq

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Acta Cryst. (2002). E58, o279–o281

Cl3 0.47752 (6) 0.72657 (7) 0.59258 (4) 0.05099 (13) O1 0.40290 (13) 0.45980 (12) 0.79978 (11) 0.0270 (2) O2 0.23758 (14) 0.54991 (11) 0.97001 (10) 0.02560 (19) O3 0.65035 (13) 0.72929 (12) 0.89273 (11) 0.0263 (2) O4 0.83858 (13) 0.92835 (12) 0.85109 (12) 0.0294 (2) N 0.03102 (15) 0.24810 (14) 0.91265 (12) 0.0222 (2) C1 0.26405 (16) 0.44550 (15) 0.86814 (13) 0.0207 (2) C2 0.13296 (17) 0.28081 (15) 0.80351 (13) 0.0214 (2) C3 −0.00515 (18) 0.28336 (17) 0.67831 (14) 0.0261 (2) C4 0.0915 (3) 0.2638 (3) 0.55220 (18) 0.0449 (4) C5 −0.1044 (2) 0.4382 (2) 0.70797 (17) 0.0352 (3) C6 0.68459 (17) 0.84578 (14) 0.84195 (13) 0.0202 (2) C7 0.51198 (17) 0.88333 (16) 0.75411 (14) 0.0241 (2) H10 0.475 (4) 0.559 (3) 0.835 (3) 0.056 (7)* H1N 0.116 (3) 0.251 (2) 0.984 (2) 0.035 (5)* H2N −0.033 (3) 0.153 (3) 0.885 (2) 0.032 (5)* H3N −0.042 (3) 0.328 (2) 0.9425 (19) 0.030 (5)* H2 0.206 (3) 0.192 (2) 0.7769 (18) 0.023 (4)* H3 −0.101 (3) 0.181 (2) 0.659 (2) 0.032 (5)* H41 0.182 (4) 0.360 (3) 0.565 (3) 0.057 (7)* H42 −0.002 (4) 0.248 (3) 0.470 (3) 0.067 (8)* H43 0.160 (3) 0.169 (3) 0.535 (2) 0.045 (6)* H51 −0.195 (3) 0.438 (3) 0.631 (2) 0.051 (6)* H52 −0.016 (3) 0.537 (3) 0.724 (2) 0.047 (6)* H53 −0.169 (3) 0.456 (3) 0.788 (2) 0.047 (6)*

Atomic displacement parameters (Å2)

U11 U22 U33 U12 U13 U23

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Acta Cryst. (2002). E58, o279–o281

Geometric parameters (Å, º)

Cl1—C7 1.7747 (14) C2—C3 1.5320 (19) Cl2—C7 1.7580 (14) C2—H2 0.957 (18) Cl3—C7 1.7749 (17) C3—C5 1.525 (2) O1—C1 1.3150 (16) C3—C4 1.531 (2) O1—H10 0.89 (3) C3—H3 1.00 (2) O2—C1 1.2136 (17) C4—H41 0.96 (3) O3—C6 1.2538 (15) C4—H42 0.98 (3) O4—C6 1.2300 (15) C4—H43 0.97 (2) N—C2 1.4953 (17) C5—H51 0.96 (2) N—H1N 0.89 (2) C5—H52 0.96 (2) N—H2N 0.84 (2) C5—H53 0.98 (2) N—H3N 0.90 (2) C6—C7 1.5578 (18) C1—C2 1.5197 (17)

C1—O1—H10 111.8 (16) C3—C4—H41 110.6 (15) C2—N—H1N 108.5 (13) C3—C4—H42 110.3 (17) C2—N—H2N 110.6 (14) H41—C4—H42 110 (2) H1N—N—H2N 108.0 (18) C3—C4—H43 112.7 (13) C2—N—H3N 111.8 (12) H41—C4—H43 106 (2) H1N—N—H3N 106.9 (18) H42—C4—H43 107 (2) H2N—N—H3N 110.8 (18) C3—C5—H51 112.5 (14) O2—C1—O1 125.57 (11) C3—C5—H52 110.3 (14) O2—C1—C2 122.27 (11) H51—C5—H52 104.8 (19) O1—C1—C2 112.15 (11) C3—C5—H53 114.8 (13) N—C2—C1 107.11 (11) H51—C5—H53 107.3 (19) N—C2—C3 111.25 (10) H52—C5—H53 106.5 (19) C1—C2—C3 112.46 (10) O4—C6—O3 127.11 (12) N—C2—H2 107.2 (11) O4—C6—C7 117.64 (11) C1—C2—H2 109.2 (11) O3—C6—C7 115.22 (11) C3—C2—H2 109.5 (11) C6—C7—Cl2 112.03 (9) C5—C3—C4 111.94 (15) C6—C7—Cl1 111.82 (9) C5—C3—C2 112.10 (11) Cl2—C7—Cl1 108.40 (8) C4—C3—C2 111.28 (13) C6—C7—Cl3 105.78 (9) C5—C3—H3 108.9 (11) Cl2—C7—Cl3 109.62 (8) C4—C3—H3 107.7 (11) Cl1—C7—Cl3 109.13 (8) C2—C3—H3 104.5 (11)

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Acta Cryst. (2002). E58, o279–o281

Hydrogen-bond geometry (Å, º)

D—H···A D—H H···A D···A D—H···A

O1—H10···O3 0.89 (3) 1.72 (3) 2.601 (2) 169 (2) N—H2N···O4i 0.84 (2) 1.93 (2) 2.761 (2) 169.6 (19) N—H1N···O3ii 0.89 (2) 1.94 (2) 2.804 (2) 163.6 (19) N—H3N···O2iii 0.90 (2) 2.00 (2) 2.871 (2) 162.5 (17)

Figure

Figure 1

References

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