β Alaninium perchlorate

organic papers

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Structure Reports

Online ISSN 1600-5368

b

-Alaninium perchlorate

S. Pandiarajan, B. Sridhar and R. K. Rajaram*

Department of Physics, Madurai Kamaraj University, Madurai 625 021, India

Correspondence e-mail: sshiya@yahoo.com

Key indicators

Single-crystal X-ray study

T= 293 K

Mean(C±C) = 0.005 AÊ Disorder in solvent or counterion

Rfactor = 0.062

wRfactor = 0.216 Data-to-parameter ratio = 9.5

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

#2001 International Union of Crystallography Printed in Great Britain ± all rights reserved

In the title compound, C3H8NO2+ClO4ÿ, a normal OÐH O

hydrogen bond is observed which forms a dimer between the carboxylic acid groups of two-alaninium residues related by an inversion center. An intramolecular hydrogen bond is observed between the amino-N and carboxyl-O atoms. The amino-N atom is also involved in a three-centered hydrogen bond with O atoms of the perchlorate anion across the center of inversion, forming in®nite chains.

Comment

Alanine is the second simplest amino acid, but the most common in proteins.-Alanine is the only naturally occurring

-amino acid. The crystal structure ofl-alanine (Lehmannet al., 1972),l-alanine hydrochloride (Di Blasioet al., 1977), -alanine (Papavinasamet al., 1986), bis(dl-alanine) phosphate (Averbuch-Pouchot et al., 1988), dl-alanine nitrate (Asath Bahadur & Rajaram, 1995) and bis(-alanine) hydrogen nitrate (Sridharet al., 2001) have been reported. In the present investigation, -alanine was reacted with perchloric acid to produce the title compound (I) which was investigated to study the conformation and hydrogen bonds in the presence of an inorganic acid.

The asymmetric unit of (I) consists of one -alaninium residue and a perchlorate anion. The backbone conformation angles 1_and 2_{are 8.0 (4) andÿ171.5 (3), respectively, for}

the alaninium residue. The straight-chain conformation angle

1_{is in thegaucheII form [ÿ65.0 (3)].}

In the perchlorate anion, all the O atoms are found to have orientational disorder. This leads to considerable variations in the ClÐO bond distances and the tetrahedral symmetry of the anion.

In biological molecules, such as amino acids, hydrogen bonds play an important role. In the present structure, a normal OÐH O hydrogen bond (2.726 AÊ) is observed, which forms a dimer between the carboxylic acid groups of two-alaninium residues related by an inversion center. The

hydrogen bonds that exist between the perchlorate anion and the alaninium residue play an important role in stabilizing the structure. The amino-N atom is also involved in a chelated three-centered hydrogen bond with acceptor O atoms (O2 and O3) of the perchlorate anion. The amino-N atom is also found to be engaged in a three-centered hydrogen bond, with (i) the carboxyl atom O1A (intramolecular hydrogen bond) and atom O4 of the perchlorate anion and (ii) two O atoms of the perchlorate anions across a center of inversion, forming in®-nite chains. The presence of the three-centered hydrogen bond is due to an excess of acceptors over donors or proton de®-ciency (Jeffrey & Saenger, 1991).

Experimental

The title compound was crystallized from an aqueous solution of -alanine and perchloric acid in a 1:1 stoichiometric ratio by slow evaporation.

Crystal data

C3H8NO2+ClO4ÿ

Mr= 189.55 Monoclinic,P21=n

a= 7.024 (3) AÊ

b= 7.556 (4) AÊ

c= 14.102 (4) AÊ

= 97.52 (4)

V= 742.0 (5) AÊ3

Z= 4

Dx= 1.697 Mg mÿ3

Dm= 1.690 Mg mÿ3

Dmmeasured by ¯otation using a mixture of carbon tetrachloride and xylene

MoKradiation Cell parameters from 25

re¯ections

= 6.4±13.6 = 0.50 mmÿ1

T= 293 (2) K Needle, colorless 0.30.20.1 mm

Data collection

Enraf±Nonis CAD-4 diffractometer

!±2scans

Absorption correction: scan (Northet al., 1968)

Tmin= 0.886,Tmax= 0.951

1521 measured re¯ections 1297 independent re¯ections 1049 re¯ections withI> 2(I)

Rint= 0.029 max= 24.8

h=ÿ8!8

k= 0!8

l= 0!16

3 standard re¯ections frequency: 60 min intensity decay: none

Re®nement

Re®nement onF2

R[F2_{> 2(F}2_{)] = 0.062}

wR(F2_{) = 0.216}

S= 1.12 1297 re¯ections 136 parameters

H-atom parameters constrained

w= 1/[2_(F

o2) + (0.1724P)2] whereP= (Fo2+ 2Fc2)/3 (/)max= 0.001

max= 0.48 e AÊÿ3 min=ÿ0.39 e AÊÿ3

Table 1

Selected geometric parameters (AÊ,_).

O1AÐC11 1.213 (4) O1BÐC11 1.287 (4)

O1AÐC11ÐC12ÐC13 8.0 (4)

O1BÐC11ÐC12ÐC13 ÿ171.5 (3) C11ÐC12ÐC13ÐN11 ÿ65.0 (3)

Table 2

Hydrogen-bonding geometry (AÊ,_).

DÐH A DÐH H A D A DÐH A

O1BÐH12 O1Ai _{0.82 1.94 2.726 (3) 161}

N11ÐH11A O2ii _{0.89 2.37 3.243 (12) 165}

N11ÐH11A O20ii _{0.89 2.06 2.939 (10) 172}

N11ÐH11A O3ii _{0.89 2.60 3.288 (9) 135}

N11ÐH11A O30ii _{0.89 2.55 3.19 (2) 130}

N11ÐH11B O4iii _{0.89 2.24 2.941 (9) 135}

N11ÐH11B O40iii _{0.89 2.46 3.19 (3) 139}

N11ÐH11B O1A 0.89 2.27 2.875 (3) 125 N11ÐH11C O1iv _{0.89 2.19 2.971 (15) 146}

N11ÐH11C O10iv _{0.89 2.17 2.97 (2) 149}

N11ÐH11C O1v _{0.89 2.42 3.064 (17) 129}

N11ÐH11C O10v _{0.89 2.49 3.10 (2) 127} Symmetry codes: (i) 1ÿx;2ÿy;1ÿz; (ii)3

2ÿx;12‡y;32ÿz; (iii) 1‡x;1‡y;z; (iv)

1‡x;y;z; (v) 1ÿx;1ÿy;1ÿz.

Acta Cryst.(2001). E57, o1130±o1132 S. Pandiarajanet al. C₃H₈NO₂+ClO₄ÿ

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organic papers

Figure 1

The molecular structures of the cation and anion of (I), showing the atomic numbering scheme and 50% probability displacement ellipsoids (Johnson, 1976). The minor-site disordered O atoms have been omitted.

Figure 2

organic papers

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The perchlorate anion exhibits orientational disorder. The site-occupation factors for O1/O2/O3/O4 and O10_/O20_/O30_/O40 _{are 0.57}

and 0.43, respectively. These O atoms were re®ned anisotropically with ®xed site-occupation factors. All H atoms were ®xed by geometric constraints using HFIX and allowed to ride on the attached atom.

Data collection: CAD-4 Software (Enraf±Nonius, 1989); cell re®nement: CAD-4 Software; data reduction: CAD-4 Software; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to re®ne structure:SHELXL97 (Sheldrick, 1997); molecular graphics:PLATON(Spek, 1999); software used to prepare material for publication:SHELXL97.

BS and RKR thank the Department of Science and Tech-nology (DST), Government of India, for ®nancial support. One of the authors (SPR) thanks the University Grants Commission, New Delhi, and the management of Devanga Arts college, Aruppukottai, India, for permitting him to pursue his doctoral research work under the Faculty Improvement Programme.

References

Asath Bahadur, S. & Rajaram, R. K. (1995).Z. Kristallogr.210, 276±278. Averbuch-Pouchot, M. T., Durif, A. & Guitel, J. C. (1988).Acta Cryst.C44,

1968±1972.

Di Blasio, B., Pavone, V. & Padone, C. (1977).Cryst. Struct. Commun.6, 745± 748.

Enraf±Nonius (1989).CAD-4 Software. Version 5.0. Enraf±Nonius, Delft, The Netherlands.

Jeffrey, G. A. & Saenger, W. (1991). Hydrogen Bonding in Biological Structures. Berlin, Heidelberg, New York: Springer-Verlag.

Johnson, C. K. (1976).ORTEPII. Report ORNL-5138. Oak Ridge National Laboratory, Tennessee, USA.

Lehmann, M. S., Koetzle, T. F. & Hamilton, W. C. (1972).J. Am. Chem. Soc.94, 2657±2660.

North, A. C. T., Phillips, D. C. & Mathews, F. S. (1968).Acta Cryst.A24, 351± 359.

Papavinasam, E., Natarajan, S. & Shivaprakash, N. C. (1986).Int. J. Pept. Protein Res.28, 525±528.

Sheldrick, G. M. (1997). SHELXL97 and SHELXS97. University of GoÈttingen, Germany.

Spek, A. L. (1999). PLATON for Windows. Utretcht University, The Netherlands.

supporting information

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supporting information

Acta Cryst. (2001). E57, o1130–o1132 [doi:10.1107/S1600536801018128]

β

-Alaninium perchlorate

S. Pandiarajan, B. Sridhar and R. K. Rajaram

S1. Comment

Alanine is the second simplest amino acid, but the most common in proteins. β-Alanine is the only naturally occurring β

-amino acid. The crystal structure of L-alanine (Lehmann et al., 1972), L-alanine hydrochloride (Di Blasio et al., 1977), β

-alanine (Papavinasam et al., 1986), bis(DL-alanine) phosphate (Averbuch-Pouchot et al., 1988), DL-alanine nitrate

(Asath Bahadur & Rajaram, 1995) and bis (β-alanine) hydrogen nitrate (Sridhar et al., 2001) have been reported. In the

present investigation, β-alanine was reacted with perchloric acid to produe the title compound (I) which was investigated

to study the conformation and hydrogen bonds in the presence of an inorganic acid.

The asymmetric unit of (I) consists of one β-alaninium residue and a perchlorate anion. The backbone conformation

angles ψ1 _{and ψ}2 _{are 8.0 (4) and -171.5 (3)°, respectively, for the alaninium residue. The straight-chain conformation}

angle χ1 _{is in the gauche II form [-65.0 (3)°].}

In the perchlorate anion, all the O atoms are found to have orientational disorder. This leads to considerable variations in

the Cl—O bond distances and the tetrahedral symmetry of the anion.

In biological molecules, such as amino acids, hydrogen bonds play an important role. In the present structure, a normal

O—H···O hydrogen bond (2.726 Å) is observed which forms a dimer between the carboxylic acid groups of two β

-alaninium residues related by an inversion center. The hydrogen bonds that exist between the perchlorate anion and the

alaninium residue play an important role in stabilizing the structure. The amino N atom is also involved in a chelated

three-centered hydrogen bond with acceptor O atoms (O2 and O3) of the perchlorate anion. The amino N atom is also

found to be engaged in a three-centered hydrogen bond, with (i) the carboxyl atom O1A (intramolecular hydrogen bond)

and atom O4 of the perchlorate anion and (ii) two O atoms of the perchlorate anions across a center of inversion, forming

infinite chains. The presence of the three-centered hydrogen bond is due to an excess of acceptors over donors or proton

deficiency (Jeffrey & Saenger, 1991).

S2. Experimental

The title compound was crystallized from an aqueous solution of β-alanine and perchloric acid in a 1:1 stoichiometric

ratio by slow evaporation.

S3. Refinement

The perchlorate anion exhibits orientational disorder. The site-occupation factors for O1/O2/O3/O4 and O1′/O2′/O3′/O4′

are 0.57 and 0.43, respectively. These O atoms were refined anisotropically with fixed site-occupation factors. All H

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Figure 1

The molecular structures of the cation and anion of (I), showing the atomic numbering scheme and 50% probability

displacement ellipsoids (Johnson, 1976). The minor-site disordered O atoms have been omitted.

Figure 2

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β-alaninium perchlorate

Crystal data

C3H8NO2+·ClO4− Mr = 189.55

Monoclinic, P21/n a = 7.024 (3) Å

b = 7.556 (4) Å

c = 14.102 (4) Å

β = 97.52 (4)°

V = 742.0 (5) Å3 Z = 4

F(000) = 392

Dx = 1.697 Mg m−3 Dm = 1.690 Mg m−3

Dm measured by flotation using a mixture of carbon tetrachloride and xylene

Mo Kα radiation, λ = 0.71073 Å Cell parameters from 25 reflections

θ = 6.4–13.6°

µ = 0.50 mm−1 T = 293 K Needle, colorless 0.3 × 0.2 × 0.1 mm

Data collection

Enraf-Nonis CAD-4 diffractometer

Radiation source: fine-focus sealed tube Graphite monochromator

ω–2θ scans

Absorption correction: ψ scan (North et al., 1968)

Tmin = 0.886, Tmax = 0.951 1521 measured reflections

1297 independent reflections 1049 reflections with I > 2σ(I)

Rint = 0.029

θmax = 24.8°, θmin = 2.9°

h = −8→8

k = 0→8

l = 0→16

3 standard reflections every 60 min intensity decay: none

Refinement

Refinement on F2

Least-squares matrix: full

R[F2 _{> 2σ(F}2_{)] = 0.062} wR(F2_{) = 0.216} S = 1.12 1297 reflections 136 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

H-atom parameters constrained

w = 1/[σ2_(Fo2_{) + (0.1724P)}2_]

where P = (Fo2 _{+ 2Fc}2_)/3

(Δ/σ)max = 0.001

Δρmax = 0.48 e Å−3

Δρmin = −0.39 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 F}2_,

conventional R-factors R are based on F, with F set to zero for negative F2_{. The threshold expression of F}2 _{> σ(F}2_{) 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 Occ. (<1)

Cl1 0.13952 (11) 0.24718 (8) 0.63655 (6) 0.0451 (5)

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O2 0.0861 (17) 0.2379 (18) 0.7242 (9) 0.142 (5) 0.57 O3 0.3261 (15) 0.273 (2) 0.6322 (7) 0.178 (7) 0.57 O4 0.1127 (18) 0.0873 (11) 0.5831 (7) 0.122 (3) 0.57 O1′ 0.117 (3) 0.380 (2) 0.5706 (14) 0.113 (6) 0.43 O2′ 0.1444 (14) 0.3251 (11) 0.7333 (8) 0.074 (3) 0.43 O3′ 0.316 (3) 0.157 (3) 0.6435 (11) 0.197 (13) 0.43 O4′ −0.016 (3) 0.153 (4) 0.6366 (11) 0.236 (11) 0.43 O1A 0.6625 (3) 0.9350 (3) 0.58291 (18) 0.0535 (7)

O1B 0.4108 (4) 0.7704 (3) 0.5274 (2) 0.0569 (8) H12 0.3714 0.8640 0.5028 0.085* C11 0.5775 (4) 0.7949 (4) 0.5755 (2) 0.0401 (7) C12 0.6627 (4) 0.6308 (5) 0.6248 (2) 0.0509 (8) H12A 0.5684 0.5772 0.6603 0.061* H12B 0.6914 0.5465 0.5768 0.061* C13 0.8431 (5) 0.6667 (4) 0.6921 (2) 0.0512 (9) H13A 0.8164 0.7550 0.7386 0.061* H13B 0.8829 0.5591 0.7266 0.061* N11 1.0036 (4) 0.7311 (3) 0.6404 (2) 0.0487 (8) H11A 1.1073 0.7512 0.6824 0.073* H11B 0.9682 0.8308 0.6094 0.073* H11C 1.0304 0.6493 0.5987 0.073*

Atomic displacement parameters (Å2₎

U11 _U22 _U33 _U12 _U13 _U23

Cl1 0.0484 (7) 0.0417 (7) 0.0469 (7) 0.0035 (3) 0.0124 (4) 0.0032 (2) O1 0.40 (3) 0.139 (13) 0.076 (8) 0.160 (16) 0.024 (11) −0.001 (8) O2 0.108 (7) 0.243 (16) 0.072 (5) −0.013 (7) 0.003 (4) 0.003 (8) O3 0.096 (6) 0.33 (2) 0.092 (6) −0.062 (8) −0.049 (5) 0.056 (8) O4 0.178 (9) 0.084 (4) 0.109 (6) −0.025 (5) 0.039 (7) 0.003 (4) O1′ 0.184 (12) 0.087 (10) 0.072 (9) −0.032 (9) 0.031 (8) 0.014 (7) O2′ 0.076 (6) 0.081 (6) 0.062 (4) 0.017 (4) −0.004 (4) −0.015 (4) O3′ 0.195 (17) 0.32 (3) 0.090 (9) 0.166 (19) 0.081 (11) 0.059 (13) O4′ 0.197 (16) 0.37 (3) 0.113 (11) −0.163 (18) −0.102 (12) 0.075 (15) O1A 0.0478 (14) 0.0367 (12) 0.0738 (16) 0.0015 (9) −0.0004 (11) 0.0018 (10) O1B 0.0460 (15) 0.0408 (13) 0.0805 (19) −0.0022 (8) −0.0042 (13) 0.0109 (9) C11 0.0378 (15) 0.0401 (14) 0.0439 (16) 0.0016 (13) 0.0106 (12) −0.0043 (13) C12 0.0535 (18) 0.0421 (18) 0.062 (2) 0.0031 (14) 0.0263 (14) 0.0043 (13) C13 0.0537 (18) 0.049 (2) 0.0516 (18) 0.0076 (14) 0.0096 (14) 0.0068 (12) N11 0.0452 (16) 0.0476 (16) 0.0522 (17) 0.0052 (10) 0.0026 (12) 0.0012 (10)

Geometric parameters (Å, º)

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Cl1—O3′ 1.410 (14) C13—H13A 0.9700 Cl1—O4 1.424 (9) C13—H13B 0.9700 Cl1—O2′ 1.483 (10) N11—H11A 0.8900 O1A—C11 1.213 (4) N11—H11B 0.8900 O1B—C11 1.287 (4) N11—H11C 0.8900 O1B—H12 0.8200

O4′—Cl1—O1 96.7 (15) O1′—Cl1—O2′ 108.7 (9) O4′—Cl1—O3 155.2 (17) O3′—Cl1—O2′ 102.4 (9) O1—Cl1—O3 99.6 (12) O4—Cl1—O2′ 144.1 (6) O4′—Cl1—O2 68.6 (11) C11—O1B—H12 109.5 O1—Cl1—O2 122.1 (10) O1A—C11—O1B 125.0 (3) O3—Cl1—O2 116.4 (6) O1A—C11—C12 121.2 (3) O4′—Cl1—O1′ 112.4 (12) O1B—C11—C12 113.8 (3) O1—Cl1—O1′ 16.2 (17) C13—C12—C11 113.2 (3) O3—Cl1—O1′ 83.5 (11) C13—C12—H12A 108.9 O2—Cl1—O1′ 130.2 (11) C11—C12—H12A 108.9 O4′—Cl1—O3′ 117.7 (18) C13—C12—H12B 108.9 O1—Cl1—O3′ 129.5 (12) C11—C12—H12B 108.9 O3—Cl1—O3′ 38.1 (12) H12A—C12—H12B 107.8 O2—Cl1—O3′ 105.1 (8) N11—C13—C12 112.0 (3) O1′—Cl1—O3′ 115.3 (12) N11—C13—H13A 109.2 O4′—Cl1—O4 58.9 (14) C12—C13—H13A 109.2 O1—Cl1—O4 101.5 (9) N11—C13—H13B 109.2 O3—Cl1—O4 99.4 (8) C12—C13—H13B 109.2 O2—Cl1—O4 114.2 (7) H13A—C13—H13B 107.9 O1′—Cl1—O4 105.6 (10) C13—N11—H11A 109.5 O3′—Cl1—O4 71.3 (11) C13—N11—H11B 109.5 O4′—Cl1—O2′ 97.7 (12) H11A—N11—H11B 109.5 O1—Cl1—O2′ 108.6 (7) C13—N11—H11C 109.5 O3—Cl1—O2′ 94.6 (7) H11A—N11—H11C 109.5 O2—Cl1—O2′ 31.5 (6) H11B—N11—H11C 109.5

O1A—C11—C12—C13 8.0 (4) C11—C12—C13—N11 −65.0 (3) O1B—C11—C12—C13 −171.5 (3)

Hydrogen-bond geometry (Å, º)

D—H···A D—H H···A D···A D—H···A

O1B—H12···O1Ai _{0.82 1.94 2.726 (3) 161}

N11—H11A···O2ii _{0.89 2.37 3.243 (12) 165}

N11—H11A···O2′ii _{0.89 2.06 2.939 (10) 172}

N11—H11A···O3ii _{0.89 2.60 3.288 (9) 135}

N11—H11A···O3′ii _{0.89 2.55 3.19 (2) 130}

N11—H11B···O4iii _{0.89 2.24 2.941 (9) 135}

N11—H11B···O4′iii _{0.89 2.46 3.19 (3) 139}

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N11—H11C···O1′iv _{0.89 2.17 2.97 (2) 149}

N11—H11C···O1v _{0.89 2.42 3.064 (17) 129}

N11—H11C···O1′v _{0.89 2.49 3.10 (2) 127}