metal-organic compounds
A redetermination of the structure of poly[[μ4-(R)-2-ammonio-3-sulfonatopropanoato]aquasodium], originally reported as poly[[μ7-L-cysteato(2−)]disodium]
aBrockhouse Institute for Materials Research, McMaster University Hamilton, Ontario, Canada L8S 4M1
*Correspondence e-mail: idbrown@mcmaster.ca
The structure originally reported as poly[[μ7-L-cysteato(2−)]disodium], [Na2(C3H5NO5S)]n [Liu (2002). Acta Cryst. E67, m1346–m1347], has been redetermined with one of the sodium atoms replaced with a water molecule and an additional proton attached to the amine group, resulting in the revised formula [Na{CO2CH(CH2SO3)NH3}(H2O)]n. The agreement index, wR, has been reduced from 0.159 to 0.087 and the global instability index from 0.56 vu (valence units) to the acceptable value of 0.11 vu.
Related literature
The original ). The bond-valence methods are described in Brown (2002).
of this compound was reported by Liu (2011Experimental
Crystal data
|
Refinement
|
|
Data collection: PROCESS-AUTO (Rigaku, 1998); cell PROCESS-AUTO; data reduction: CrystalStructure (Rigaku/MSC, 2002); method used to solve structure: coordinates taken from the previous (Liu, 2011); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: Mercury (Macrae et al., 2006); software used to prepare material for publication: publCIF (Westrip, 2010).
Supporting information
10.1107/S1600536812009683/sj5205sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536812009683/sj5205Isup2.hkl
The structure was refined using the original diffraction measurements of Liu (2011). For re-refinement of the original model, all H atoms were removed in the first
cycle and the doubtful atom Na2 replaced by an O atom (O1W). All H atoms were discernible from difference maps. H atoms attached to C atoms were finally included in calculated positions using a riding model with bond lengths C—H = 0.97 or 0.98 Å and Uiso(H) = 1.2 times Ueq(C); H atoms attached to the ammonium group were constrained to bond lengths N—H = 0.89 Å with Uiso(H) = 1.5 times Ueq(N). The water H atoms were restrained to bond lengths of 0.85 (1) Å.In a recent issue of this journal, Liu (2011) reported the structure of the title compound, but a close examination of this structure shows a serious problem with the environment of one of the sodium atoms, Na2. In the Comment the author describes this atom as 'tetracoordinated within an NO3 coordination sphere. The Na+ ion binds to the amino N atom, to one of the O atom of the carboxylic residue and to two O atoms of the sulfonate group in a distorted tetrahedral arrangement'. The Comment does not point out that the atomic displacement parameter of Na2 is almost three times larger than the next largest atomic displacement parameter, nor does it point out that the lengths of the four bonds around Na2 all lie in the range 2.90 to 3.03 Å, distances whose bond valence sum of 0.21 vu (valence unit) indicates that they are much longer than would be expected for a four-coordinate sodium cation. The global instability index [root mean square deviation of the bond valence sums of all atoms from their atomic valence, (Brown, 2002)] is 0.56 vu, much higher than the generally accepted limit of 0.20 vu for a stable structure. The environment of Na2 is, however, one that would be expected for a water molecule that forms moderate to weak hydrogen bonds. An additional hydrogen ion is required for charge neutrality, but protonating the water molecule is unlikely as this would require much shorter hydrogen bonds than are observed for this site, but protonating the amine group would not only increase the bond valence sum around the nitrogen from 2.51 vu to a value closer to the expected 3.00 vu, it would also result in an N—H bond positioned to form a hydrogen bond with the water molecule.
This proposed model has been refined and is reported in this paper. The bond valence sum of 0.21 vu around the original Na2 has been replaced by a sum of 1.94 vu around the oxygen of water, and the sum around the N1 atom has been increased to 3.17 vu. Moreover, Na1 now has a meaningful octahedral environment (Fig. 1) with a Na1—O1W contact of 2.450 (2) Å instead of a Na1—Na2 contact as in the original model.
Based on the rerefinement of the structure, this crystal must be reformulated as sodium (R)-2-ammonium-3-sulfopropanoate monohydrate, Na(CO2CH(CH2SO3)NH3)(H2O).
The original
of this compound was reported by Liu (2011). The bond-valence methods are described in Brown (2002).Data collection: PROCESS-AUTO (Rigaku, 1998); cell
PROCESS-AUTO (Rigaku, 1998); data reduction: CrystalStructure (Rigaku/MSC, 2002); program(s) used to solve structure: coordinates taken from the previous (Liu, 2011); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: Mercury (Macrae et al., 2006); software used to prepare material for publication: publCIF (Westrip, 2010).[Na(C3H6NO5S)(H2O)] | F(000) = 432 |
Mr = 209.15 | Dx = 1.840 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 7309 reflections |
a = 5.7574 (12) Å | θ = 3.4–27.5° |
b = 11.875 (2) Å | µ = 0.48 mm−1 |
c = 11.691 (3) Å | T = 298 K |
β = 109.15 (3)° | Prism, colourless |
V = 755.1 (3) Å3 | 0.24 × 0.22 × 0.20 mm |
Z = 4 |
Rigaku SCX-Mini CCD diffractometer | 1740 independent reflections |
Radiation source: fine-focus sealed tube | 1463 reflections with I > 2Σ(I) |
Graphite monochromator | Rint = 0.044 |
ω scans | θmax = 27.5°, θmin = 3.4° |
Absorption correction: multi-scan (ABSCOR; Higashi, 1995) | h = −7→7 |
Tmin = 0.894, Tmax = 0.911 | k = −15→15 |
7845 measured reflections | l = −15→15 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.038 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.087 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.10 | w = 1/[σ2(Fo2) + (0.0337P)2 + 0.5281P] where P = (Fo2 + 2Fc2)/3 |
1740 reflections | (Δ/σ)max = 0.001 |
118 parameters | Δρmax = 0.39 e Å−3 |
2 restraints | Δρmin = −0.35 e Å−3 |
[Na(C3H6NO5S)(H2O)] | V = 755.1 (3) Å3 |
Mr = 209.15 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 5.7574 (12) Å | µ = 0.48 mm−1 |
b = 11.875 (2) Å | T = 298 K |
c = 11.691 (3) Å | 0.24 × 0.22 × 0.20 mm |
β = 109.15 (3)° |
Rigaku SCX-Mini CCD diffractometer | 1740 independent reflections |
Absorption correction: multi-scan (ABSCOR; Higashi, 1995) | 1463 reflections with I > 2Σ(I) |
Tmin = 0.894, Tmax = 0.911 | Rint = 0.044 |
7845 measured reflections |
R[F2 > 2σ(F2)] = 0.038 | 2 restraints |
wR(F2) = 0.087 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.10 | Δρmax = 0.39 e Å−3 |
1740 reflections | Δρmin = −0.35 e Å−3 |
118 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
Na1 | 0.04743 (15) | 0.74874 (7) | 0.32550 (8) | 0.0227 (2) | |
C1 | 0.2113 (4) | 1.00587 (18) | 0.31408 (19) | 0.0187 (4) | |
C2 | 0.4306 (4) | 1.03306 (18) | 0.27159 (19) | 0.0183 (4) | |
H2 | 0.4392 | 1.1153 | 0.2677 | 0.022* | |
C3 | 0.3962 (4) | 0.98919 (18) | 0.14342 (19) | 0.0202 (5) | |
H3A | 0.5201 | 1.0241 | 0.1155 | 0.024* | |
H3B | 0.2371 | 1.0146 | 0.0905 | 0.024* | |
N1 | 0.6664 (3) | 0.99540 (16) | 0.36077 (16) | 0.0229 (4) | |
H1A | 0.6638 | 0.9210 | 0.3694 | 0.034* | |
H1B | 0.6869 | 1.0284 | 0.4318 | 0.034* | |
H1C | 0.7900 | 1.0143 | 0.3347 | 0.034* | |
O1 | 0.2380 (3) | 0.93424 (13) | 0.39576 (13) | 0.0244 (4) | |
O2 | 0.0199 (3) | 1.06104 (14) | 0.26136 (16) | 0.0294 (4) | |
O3 | 0.2321 (3) | 0.78831 (14) | 0.17151 (15) | 0.0310 (4) | |
O4 | 0.6636 (3) | 0.80928 (14) | 0.19436 (15) | 0.0300 (4) | |
O5 | 0.3578 (3) | 0.82358 (14) | −0.00367 (13) | 0.0251 (4) | |
S1 | 0.41302 (9) | 0.84075 (4) | 0.12587 (5) | 0.01761 (15) | |
O1W | −0.1946 (4) | 0.76543 (17) | 0.46236 (17) | 0.0356 (4) | |
H1WA | −0.090 (5) | 0.759 (4) | 0.5329 (15) | 0.090 (15)* | |
H1WB | −0.326 (3) | 0.740 (3) | 0.471 (3) | 0.058 (10)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Na1 | 0.0214 (5) | 0.0242 (5) | 0.0216 (5) | 0.0005 (4) | 0.0058 (4) | 0.0015 (4) |
C1 | 0.0195 (11) | 0.0171 (10) | 0.0209 (11) | −0.0036 (9) | 0.0087 (9) | −0.0060 (9) |
C2 | 0.0178 (10) | 0.0169 (10) | 0.0221 (11) | 0.0000 (8) | 0.0091 (9) | −0.0003 (8) |
C3 | 0.0228 (11) | 0.0187 (11) | 0.0209 (11) | 0.0011 (9) | 0.0094 (9) | 0.0013 (9) |
N1 | 0.0174 (9) | 0.0297 (10) | 0.0223 (10) | −0.0022 (8) | 0.0073 (8) | −0.0045 (8) |
O1 | 0.0275 (9) | 0.0259 (8) | 0.0216 (8) | −0.0031 (7) | 0.0105 (7) | 0.0012 (7) |
O2 | 0.0195 (8) | 0.0306 (9) | 0.0411 (10) | 0.0060 (7) | 0.0139 (7) | 0.0091 (8) |
O3 | 0.0366 (10) | 0.0311 (9) | 0.0319 (9) | −0.0106 (8) | 0.0203 (8) | −0.0026 (7) |
O4 | 0.0256 (9) | 0.0286 (9) | 0.0291 (9) | 0.0075 (7) | 0.0000 (7) | −0.0007 (7) |
O5 | 0.0264 (8) | 0.0309 (9) | 0.0184 (8) | −0.0045 (7) | 0.0079 (7) | −0.0053 (6) |
S1 | 0.0193 (3) | 0.0179 (3) | 0.0160 (3) | −0.0013 (2) | 0.0063 (2) | −0.0006 (2) |
O1W | 0.0274 (10) | 0.0517 (12) | 0.0302 (10) | 0.0023 (9) | 0.0127 (9) | 0.0119 (9) |
Na1—O4i | 2.3512 (19) | C3—S1 | 1.781 (2) |
Na1—O5ii | 2.3619 (19) | C3—H3A | 0.9700 |
Na1—O3 | 2.4183 (18) | C3—H3B | 0.9700 |
Na1—O2iii | 2.4272 (19) | N1—H1A | 0.8900 |
Na1—O1W | 2.450 (2) | N1—H1B | 0.8900 |
Na1—O1 | 2.4778 (18) | N1—H1C | 0.8900 |
C1—O1 | 1.250 (3) | O3—S1 | 1.4567 (16) |
C1—O2 | 1.256 (3) | O4—S1 | 1.4505 (17) |
C1—C2 | 1.535 (3) | O5—S1 | 1.4561 (16) |
C2—N1 | 1.484 (3) | O1W—H1WA | 0.8499 (11) |
C2—C3 | 1.537 (3) | O1W—H1WB | 0.8500 (11) |
C2—H2 | 0.9800 | ||
O4i—Na1—O5ii | 162.02 (7) | C2—C3—H3A | 108.1 |
O4i—Na1—O3 | 90.22 (7) | S1—C3—H3A | 108.1 |
O5ii—Na1—O3 | 107.74 (7) | C2—C3—H3B | 108.1 |
O4i—Na1—O2iii | 91.21 (7) | S1—C3—H3B | 108.1 |
O5ii—Na1—O2iii | 89.57 (7) | H3A—C3—H3B | 107.3 |
O3—Na1—O2iii | 85.17 (6) | C2—N1—H1A | 109.5 |
O4i—Na1—O1W | 77.69 (7) | C2—N1—H1B | 109.5 |
O5ii—Na1—O1W | 84.94 (7) | H1A—N1—H1B | 109.5 |
O3—Na1—O1W | 162.46 (7) | C2—N1—H1C | 109.5 |
O2iii—Na1—O1W | 107.49 (7) | H1A—N1—H1C | 109.5 |
O4i—Na1—O1 | 99.41 (7) | H1B—N1—H1C | 109.5 |
O5ii—Na1—O1 | 85.01 (6) | C1—O1—Na1 | 114.94 (13) |
O3—Na1—O1 | 79.58 (6) | C1—O2—Na1iv | 132.70 (14) |
O2iii—Na1—O1 | 161.39 (6) | S1—O3—Na1 | 153.84 (11) |
O1W—Na1—O1 | 89.79 (7) | S1—O4—Na1v | 172.12 (12) |
O1—C1—O2 | 126.7 (2) | S1—O5—Na1vi | 140.97 (10) |
O1—C1—C2 | 118.85 (19) | O4—S1—O5 | 112.10 (10) |
O2—C1—C2 | 114.45 (18) | O4—S1—O3 | 112.88 (11) |
N1—C2—C1 | 111.67 (17) | O5—S1—O3 | 112.51 (10) |
N1—C2—C3 | 112.25 (17) | O4—S1—C3 | 105.86 (10) |
C1—C2—C3 | 112.80 (17) | O5—S1—C3 | 104.88 (10) |
N1—C2—H2 | 106.5 | O3—S1—C3 | 107.96 (10) |
C1—C2—H2 | 106.5 | Na1—O1W—H1WA | 105 (3) |
C3—C2—H2 | 106.5 | Na1—O1W—H1WB | 140 (2) |
C2—C3—S1 | 116.96 (15) | H1WA—O1W—H1WB | 103 (3) |
Symmetry codes: (i) x−1, y, z; (ii) x, −y+3/2, z+1/2; (iii) −x, y−1/2, −z+1/2; (iv) −x, y+1/2, −z+1/2; (v) x+1, y, z; (vi) x, −y+3/2, z−1/2. |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1A···O1Wv | 0.89 | 2.16 | 2.981 (3) | 153 |
N1—H1B···O1vii | 0.89 | 1.97 | 2.842 (2) | 166 |
N1—H1C···O2v | 0.89 | 1.88 | 2.766 (2) | 173 |
O1W—H1WA···O3ii | 0.85 (1) | 2.10 (1) | 2.912 (3) | 160 (4) |
O1W—H1WB···O5viii | 0.85 (1) | 2.08 (1) | 2.930 (2) | 178 (3) |
Symmetry codes: (ii) x, −y+3/2, z+1/2; (v) x+1, y, z; (vii) −x+1, −y+2, −z+1; (viii) x−1, −y+3/2, z+1/2. |
Experimental details
Crystal data | |
Chemical formula | [Na(C3H6NO5S)(H2O)] |
Mr | 209.15 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 298 |
a, b, c (Å) | 5.7574 (12), 11.875 (2), 11.691 (3) |
β (°) | 109.15 (3) |
V (Å3) | 755.1 (3) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.48 |
Crystal size (mm) | 0.24 × 0.22 × 0.20 |
Data collection | |
Diffractometer | Rigaku SCX-Mini CCD |
Absorption correction | Multi-scan (ABSCOR; Higashi, 1995) |
Tmin, Tmax | 0.894, 0.911 |
No. of measured, independent and observed [I > 2Σ(I)] reflections | 7845, 1740, 1463 |
Rint | 0.044 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.038, 0.087, 1.10 |
No. of reflections | 1740 |
No. of parameters | 118 |
No. of restraints | 2 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.39, −0.35 |
Computer programs: PROCESS-AUTO (Rigaku, 1998), CrystalStructure (Rigaku/MSC, 2002), coordinates taken from the previous
(Liu, 2011), SHELXL97 (Sheldrick, 2008), Mercury (Macrae et al., 2006), publCIF (Westrip, 2010).Na1—O4i | 2.3512 (19) | Na1—O2iii | 2.4272 (19) |
Na1—O5ii | 2.3619 (19) | Na1—O1W | 2.450 (2) |
Na1—O3 | 2.4183 (18) | Na1—O1 | 2.4778 (18) |
Symmetry codes: (i) x−1, y, z; (ii) x, −y+3/2, z+1/2; (iii) −x, y−1/2, −z+1/2. |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1A···O1Wiv | 0.89 | 2.16 | 2.981 (3) | 152.5 |
N1—H1B···O1v | 0.89 | 1.97 | 2.842 (2) | 166.3 |
N1—H1C···O2iv | 0.89 | 1.88 | 2.766 (2) | 172.6 |
O1W—H1WA···O3ii | 0.8499 (11) | 2.100 (14) | 2.912 (3) | 160 (4) |
O1W—H1WB···O5vi | 0.8500 (11) | 2.081 (3) | 2.930 (2) | 178 (3) |
Symmetry codes: (ii) x, −y+3/2, z+1/2; (iv) x+1, y, z; (v) −x+1, −y+2, −z+1; (vi) x−1, −y+3/2, z+1/2. |
Acknowledgements
I wish to thank Dr Liu for supplying the original diffraction measurements through the editorial office of the journal.
References
Brown, I. D. (2002). The Chemical Bond in Inorganic Chemistry, The Bond Valence Model, IUCr Monographs on Crystallography 12, p. 166. Oxford University Press. Google Scholar
Higashi, T. (1995). ABSCOR. Rigaku Corporation, Tokyo, Japan. Google Scholar
Liu, F.-H. (2011). Acta Cryst. E67, m1346–m1347. Web of Science CSD CrossRef IUCr Journals Google Scholar
Macrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor, R., Towler, M. & van de Streek, J. (2006). J. Appl. Cryst. 39, 453–457. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Rigaku (1998). PROCESS-AUTO. Rigaku Corporation, Tokyo, Japan. Google Scholar
Rigaku/MSC (2002). CrystalStructure. Rigaku/MSC, The Woodlands, Texas, USA. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Westrip, S. P. (2010). J. Appl. Cryst. 43, 920–925. Web of Science CrossRef CAS IUCr Journals Google Scholar
This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
In a recent issue of this journal, Liu (2011) reported the structure of the title compound, but a close examination of this structure shows a serious problem with the environment of one of the sodium atoms, Na2. In the Comment the author describes this atom as 'tetracoordinated within an NO3 coordination sphere. The Na+ ion binds to the amino N atom, to one of the O atom of the carboxylic residue and to two O atoms of the sulfonate group in a distorted tetrahedral arrangement'. The Comment does not point out that the atomic displacement parameter of Na2 is almost three times larger than the next largest atomic displacement parameter, nor does it point out that the lengths of the four bonds around Na2 all lie in the range 2.90 to 3.03 Å, distances whose bond valence sum of 0.21 vu (valence unit) indicates that they are much longer than would be expected for a four-coordinate sodium cation. The global instability index [root mean square deviation of the bond valence sums of all atoms from their atomic valence, (Brown, 2002)] is 0.56 vu, much higher than the generally accepted limit of 0.20 vu for a stable structure. The environment of Na2 is, however, one that would be expected for a water molecule that forms moderate to weak hydrogen bonds. An additional hydrogen ion is required for charge neutrality, but protonating the water molecule is unlikely as this would require much shorter hydrogen bonds than are observed for this site, but protonating the amine group would not only increase the bond valence sum around the nitrogen from 2.51 vu to a value closer to the expected 3.00 vu, it would also result in an N—H bond positioned to form a hydrogen bond with the water molecule.
This proposed model has been refined and is reported in this paper. The bond valence sum of 0.21 vu around the original Na2 has been replaced by a sum of 1.94 vu around the oxygen of water, and the sum around the N1 atom has been increased to 3.17 vu. Moreover, Na1 now has a meaningful octahedral environment (Fig. 1) with a Na1—O1W contact of 2.450 (2) Å instead of a Na1—Na2 contact as in the original model.
Based on the rerefinement of the structure, this crystal must be reformulated as sodium (R)-2-ammonium-3-sulfopropanoate monohydrate, Na(CO2CH(CH2SO3)NH3)(H2O).