organic papers
o634
Tat'yana N. Drebushchaket al. C2H5NO2 DOI: 10.1107/S160053680200836X Acta Cryst.(2002). E58, o634±o636 Acta Crystallographica Section EStructure Reports Online
ISSN 1600-5368
b
-Glycine
Tat'yana N. Drebushchak,a*
Elena V. Boldyrevaaand
Elena S. Shutovab
aInstitute of Solid State Chemistry and
Mechan-ochemistry, SD Russian Academy of Sciences, Kutateladze 18, Novosibirsk 128, 630128 Russia, andbNovosibirsk State University, Piro-gova street 2, Novosibirsk 90, 630090 Russia
Correspondence e-mail: [email protected]
Key indicators
Single-crystal X-ray study
T= 294 K
Mean(C±C) = 0.001 AÊ
Rfactor = 0.025
wRfactor = 0.076
Data-to-parameter ratio = 13.3
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
The crystal structure of-glycine, C2H5NO2, has been re®ned.
Single crystals of the metastable-polymorph of glycine were obtained by cooling a saturated solution of glycine containing acetic acid. The crystal of the-polymorph was preserved in dry air for several months. As the humidity of the air increased, a polymorphic transformation into the-form was observed. The cell parameters of-glycine have already been determined by Kozhin [Kristallogra®ya(1978),23, 1211±1215], but the coordinates have not been published so far.
Comment
Three polymorphs (, and ) are known for glycine. The structures of the- and-polymorphs have been re®ned from ambient and low-temperature data (JoÈnsson & Kvick, 1972; Kvicket al., 1980). The structure of the-polymorph was ®rst reported by Iitaka (1959) and later described in more detail (Iitaka, 1960). The cell parameters of-glycine, (I), have been determined by Kozhin (1978), but the coordinates have not been published so far and the structure was not re®ned again after these early publications. The data published by Iitaka were obtained by a photographic technique, the structure was re®ned to anRfactor of 4.3, and no H-atom coordinates were reported. Maybe one of the reasons for this situation is the dif®culty in obtaining single crystals of the-polymorph.
We have grown a crystal of the-polymorph and have re-solved and rere®ned its crystal structure at ambient temperature (T = 294 K), using a Stoe Stadi-4 four-circle diffractometer. The main structural features previously reported by Iitaka were con®rmed. Glycine exists in the structure in the form of zwitterions,+H
3NCH2COOÿ(Fig. 1),
which are linked together by electrostatic interactions and a three-dimensional network of hydrogen bonds (Fig. 2). The geometry of the zwitterions is similar to that in the- and -polymorphs (Iitaka, 1960). The two CÐO bonds are almost equivalent, in contrast to the data previously published by Iitaka in 1960. The difference in the torsion angles of the zwitterions in the -, - and -polymorphs is about 10
[161.8 (1) in at ambient temperature (JoÈnsson & Kvick,
1972), 157.41 (8) in(our data), 167.1 (1)in at ambient
temperature (Kvicket al., 1980)]. Both O atoms and the NH3
group are involved in the formation of hydrogen bonds. Although Iitaka could not locate H atoms in the structure, his representation of the hydrogen-bond network was correct, as
con®rmed by our more precise data. The shortest hydrogen bonds link zwitterions in layers parallel to theacplane. The third H atom of an NH3group is located between the two O
atoms of the neighbouring layer, forming a bifurcated hydrogen bond [2.23 (2) AÊ and 2.30 AÊ] linking zwitterions in thebdirection. All the layers are linked with each other by these bifurcated hydrogen bonds in a three-dimensional network. The crystal structure is polar (space groupP21). The
distance between the neighbouring layers is equal to half a translation alongb.
The structure of an individual layer of zwitterions in the -polymorph is similar to that in the-polymorph. The topology of the layers is the same for non-H atoms. The intermolecular hydrogen bonds within the layer are longer in the -poly-morph [1.87 (2) AÊ and 1.97 (2) AÊ] than they are in the -polymorph (1.77 AÊ and 1.92 AÊ). The linkage between the layers in the -polymorph is different from that in the -polymorph (Iitaka, 1960). In the latter, the bifurcated hydrogen bonds link layers of zwitterions related by mirror planes in double-layer dimer-packages. Only van der Waals interactions exist between these double layers. The formation of double layers in the-polymorph accounts for the fact that the b cell parameter in the -polymorph is approximately doubled, compared with the bcell parameter in the -poly-morph.
Iitaka reported in his early paper (Iitaka, 1960), that the -polymorph of glycine is stable in dry air for an inde®nitely long time, but transforms easily into either the- or -poly-morphs, depending on the conditions, for example, if the air is humid.
In our experiments, the crystal of the -polymorph was preserved in dry air for several months. This was con®rmed not only by optical microscopy observations, but also by several X-ray diffraction data collections during this time period. As the humidity of the air increased, a polymorphic transformation into the-form was observed. The crystals lost transparency, but preserved their original shape. X-ray diffraction data could be collected from the crystal after the transformation. Re¯ections became broader, after the
trans-formation, than they were in the diffraction pattern from the original crystal, but the structure could still be re®ned (toR= 0.22). The orientation matrix after the transformation was determined. Having compared the orientation matrices before and after the transformation, we could calculate the angles between the crystallographic axes of the product-polymorph with respect to the crystallographic axes of the parent -polymorph. Molecular layers (normal to the b direction) rotated at an angle of about 27 in the course of the ±
transformation.
A comparison of the structures of the- and-polymorphs allows one to suppose that the±transformation requires a reconstruction of the hydrogen-bond network and involves changes in the orientation of the zwitterions in every second layer of the parent structure of the-polymorph. The effect of water vapour on the transformation may be related to this structural reconstruction during the transformation.
Experimental
Single crystals of the metastable -polymorph of glycine were obtained by cooling a saturated solution of glycine containing acetic acid (volume ratio water±acid equal to 5:1) from 323 K down to 288 K. 30 ml of this solution were placed in a 50 ml glass vessel of 4 cm diameter. Simultaneously crystals of the-polymorph crystal-lized in the same vessel. According to the data previously described in the literature (Iitaka, 1960; Kvick et al., 1980), the -polymorph crystallizes from a water±ethanol solution, whereas crystallization from a water solution with acetic acid has been reported to give the
-polymorph.
Crystal data
C2H5NO2 Mr= 75.07 Monoclinic,P21 a= 5.0935 (11) AÊ b= 6.274 (2) AÊ c= 5.3847 (12) AÊ
= 113.19 (2)
V= 158.18 (8) AÊ3 Z= 2
Dx= 1.576 Mg mÿ3 Mo Kradiation Cell parameters from 26
re¯ections
= 15.1±24.7
= 0.14 mmÿ1 T= 294 (1) K Prism, colourless 0.50.40.2 mm
Data collection
Stoe Stadi-4 four-circle diffractometer
Scan width (!) = 1.42±1.87, scan
ratio 2:!= 1.00;I(Net) and(I) calculated according to Blessing (1987)
Absorption correction: scan (X-RED; Stoe, 1998) Tmin= 0.909,Tmax= 0.998 6548 measured re¯ections
894 independent re¯ections 823 re¯ections withI> 2(I) Rint= 0.039
max= 37.5 h=ÿ8!8 k=ÿ10!10 l=ÿ9!9 2 standard re¯ections
frequency: 180 min intensity decay: 4.3%
Re®nement
Re®nement onF2 R[F2> 2(F2)] = 0.025 wR(F2) = 0.076 S= 1.12 894 re¯ections 67 parameters
All H-atom parameters re®ned
w= 1/[2(F
o2) + (0.0501P)2 + 0.0031P]
whereP= (Fo2+ 2Fc2)/3 (/)max< 0.001
max= 0.29 e AÊÿ3 min=ÿ0.18 e AÊÿ3
Extinction correction:SHELXL97 Extinction coef®cient: 0.58 (7)
Acta Cryst.(2002). E58, o634±o636 Tat'yana N. Drebushchaket al. C2H5NO2
o635
organic papers
Figure 1
organic papers
o636
Tat'yana N. Drebushchaket al. C2H5NO2 Acta Cryst.(2002). E58, o634±o636Table 1
Selected geometric parameters (AÊ,).
O1ÐC1 1.2528 (9)
N1ÐC2 1.4753 (11) C1ÐO2C1ÐC2 1.2529 (11)1.5281 (11)
O1ÐC1ÐO2 125.78 (8)
O1ÐC1ÐC2 117.03 (7) O2ÐC1ÐC2N1ÐC2ÐC1 117.15 (7)111.79 (6)
O1ÐC1ÐC2ÐN1 ÿ157.41 (8) O2ÐC1ÐC2ÐN1 25.03 (12)
Table 2
Hydrogen-bonding geometry (AÊ,).
DÐH A DÐH H A D A DÐH A
N1ÐH4 O1i 0.88 (2) 1.97 (2) 2.8509 (13) 176.6 (17) N1ÐH3 O2ii 0.899 (16) 1.866 (16) 2.7626 (11) 174.4 (17) N1ÐH5 O2iii 0.89 (3) 2.30 (2) 2.9795 (15) 132.6 (14) N1ÐH5 O1iv 0.89 (3) 2.23 (2) 2.9785 (13) 140.7 (16) Symmetry codes: (i) 1x;y;z; (ii) x;y;zÿ1; (iii) 1ÿx;yÿ1
2;1ÿz; (iv)
ÿx;yÿ1 2;1ÿz.
The structure was solved and re®ned in the space groupP21, since
the crystals are piezoelectric (Iitaka, 1961), and this fact excludes the existence of a centre of symmetry. Attempts to treat the structure as a twin resulted in less precise results. Anomalous scattering effects were not treated. Friedel pairs were merged.
Data collection: STADI4 (Stoe & Cie, 1997); cell re®nement:
STADI4; data reduction: X-RED (Stoe & Cie, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to re®ne structure: SHELXL97 (Sheldrick, 1997); molecular graphics:X-STEP(Stoe & Cie, 1998) andPcw(Kraus & Nolze, 1999); software used to prepare material for publication:SHELXL97.
The study was supported by several grants: CRDF (REC-008) and grants of the Russian Ministry of Education (Program Integration, grant 274; grants 2000.5.81).
References
Blessing, R. H. (1987).Crystallogr. Rev.1, 3±58. Iitaka, Y. (1960).Acta Cryst.13, 35±45. Iitaka, Y. (1959).Nature, pp. 390±391. Iitaka, Y. (1961).Acta Cryst.14, 1±10.
JoÈnsson, P. G. & Kvick, AÊ. (1972).Acta Cryst.B28, 1827±1833. Kozhin, V. M. (1978).Kristallogra®ya,23, 1211±1215.
Kvick, AÊ., Canning, W. M., Koetzle, T. F. & Williams, G. J. B. (1980).Acta Cryst. B36, 115±120.
Kraus, W. & Nolze, G. (1999).PowderCell for Windows. Version 2.3. URL: http://www.bam.de/a_v/v_1/powder/e_cell.html.
Sheldrick, G. M. (1990).Acta Cryst.A46, 467±473.
Sheldrick, G. M. (1997).SHELXL97. University of GoÈttingen, Germany. Stoe & Cie (1997).STADI4. Stoe & Cie GmbH, Darmstadt, Germany. Stoe & Cie (1998).X-RED,X-STEPandX-SHAPE. Stoe & Cie GmbH,
Darmstadt, Germany.
Figure 2
supporting information
sup-1 Acta Cryst. (2002). E58, o634–o636
supporting information
Acta Cryst. (2002). E58, o634–o636 [https://doi.org/10.1107/S160053680200836X]
β
-Glycine
Tat'yana N. Drebushchak, Elena V. Boldyreva and Elena S. Shutova
aminoacetic acid
Crystal data C2H5NO2
Mr = 75.07
Monoclinic, P21
a = 5.0935 (11) Å b = 6.274 (2) Å c = 5.3847 (12) Å β = 113.19 (2)° V = 158.18 (8) Å3
Z = 2
F(000) = 80 Dx = 1.576 Mg m−3
Mo Kα radiation, λ = 0.71069 Å Cell parameters from 26 reflections θ = 15.1–24.7°
µ = 0.14 mm−1
T = 294 K Prism, colourless 0.5 × 0.4 × 0.2 mm
Data collection
Stoe STADI4 four-circle diffractometer
Radiation source: fine-focus sealed tube Planar graphite monochromator
Scan width (ω) = 1.42° – 1.87°, scan ratio 2θ:ω = 1.00 I(Net) and sigma(I) calculated according to Blessing (1987)
Absorption correction: ψ scan (X-RED; Stoe, 1998) Tmin = 0.909, Tmax = 0.998
6548 measured reflections 894 independent reflections 823 reflections with I > 2σ(I) Rint = 0.039
θmax = 37.5°, θmin = 3.3°
h = −8→8 k = −10→10 l = −9→9
2 standard reflections every 180 min intensity decay: 4.3%
Refinement Refinement on F2
Least-squares matrix: full R[F2 > 2σ(F2)] = 0.025
wR(F2) = 0.076
S = 1.12 894 reflections 67 parameters 1 restraint
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) + (0.0501P)2 + 0.0031P]
where P = (Fo2 + 2Fc2)/3
(Δ/σ)max < 0.001
Δρmax = 0.29 e Å−3
Δρmin = −0.18 e Å−3
Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
supporting information
sup-2 Acta Cryst. (2002). E58, o634–o636
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
O1 −0.09265 (13) 0.40990 (13) 0.59741 (13) 0.02586 (16) N1 0.35024 (16) 0.28161 (13) 0.23730 (13) 0.02090 (14) H3 0.349 (4) 0.301 (3) 0.071 (3) 0.029 (4)* H4 0.520 (4) 0.324 (3) 0.353 (4) 0.029 (4)* H5 0.340 (4) 0.142 (4) 0.266 (3) 0.034 (4)* C1 0.13352 (15) 0.38405 (13) 0.56103 (15) 0.01851 (13) O2 0.37739 (15) 0.35815 (17) 0.74274 (12) 0.0298 (2) C2 0.11150 (17) 0.39417 (16) 0.26993 (14) 0.02195 (15) H1 0.123 (4) 0.538 (4) 0.222 (4) 0.035 (5)* H2 −0.063 (4) 0.332 (3) 0.143 (4) 0.029 (4)*
Atomic displacement parameters (Å2)
U11 U22 U33 U12 U13 U23
O1 0.0234 (3) 0.0326 (4) 0.0268 (3) 0.0000 (2) 0.0154 (2) −0.0038 (2) N1 0.0218 (3) 0.0272 (3) 0.0151 (2) 0.0026 (2) 0.0087 (2) 0.0000 (2) C1 0.0204 (3) 0.0210 (3) 0.0163 (2) −0.0023 (3) 0.0096 (2) −0.0014 (2) O2 0.0208 (2) 0.0532 (5) 0.0156 (2) −0.0029 (3) 0.00725 (19) 0.0007 (3) C2 0.0232 (3) 0.0286 (4) 0.0151 (3) 0.0055 (3) 0.0087 (2) 0.0023 (3)
Geometric parameters (Å, º)
O1—C1 1.2528 (9) C1—O2 1.2529 (11)
N1—C2 1.4753 (11) C1—C2 1.5281 (11)
N1—H3 0.899 (16) C2—H1 0.95 (3)
N1—H4 0.88 (2) C2—H2 0.964 (18)
N1—H5 0.89 (3)
supporting information
sup-3 Acta Cryst. (2002). E58, o634–o636
O1—C1—C2—N1 −157.41 (8) O2—C1—C2—N1 25.03 (12)
Hydrogen-bond geometry (Å, º)
D—H···A D—H H···A D···A D—H···A
N1—H4···O1i 0.88 (2) 1.97 (2) 2.8509 (13) 176.6 (17)
N1—H3···O2ii 0.899 (16) 1.866 (16) 2.7626 (11) 174.4 (17)
N1—H5···O2iii 0.89 (3) 2.30 (2) 2.9795 (15) 132.6 (14)
N1—H5···O1iv 0.89 (3) 2.23 (2) 2.9785 (13) 140.7 (16)