Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536801017391/ci6067sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536801017391/ci6067Isup2.hkl |
CCDC reference: 176034
Colorless prismatic single crystals of (I) were grown from a saturated aqueous solution containing DL-valine and maleic acid in stoichiometric ratio.
All the H atoms were generated geometrically and were allowed to ride on their parent atoms with SHELXL97 (Sheldrick, 1997) defaults for bond lengths and displacement parameters.
Data collection: SMART (Bruker, 1999); cell refinement: SMART; data reduction: SAINT (Bruker, 1999); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 1999); software used to prepare material for publication: SHELXL97.
Fig. 1. The molecular structure of (I) with atom-numbering scheme and 50% probability displacement ellipsoids. | |
Fig. 2. Packing of the molecules of (I) viewed down the a axis. |
C5H12NO2+·C4H3O4− | Z = 2 |
Mr = 233.22 | F(000) = 248 |
Triclinic, P1 | Dx = 1.417 Mg m−3 Dm = 1.42 Mg m−3 Dm measured by flotation in a mixture of xylene and carbon tetrachloride |
a = 6.1830 (12) Å | Mo Kα radiation, λ = 0.71073 Å |
b = 9.6480 (19) Å | Cell parameters from 1024 reflections |
c = 10.534 (2) Å | θ = 2.2–26.3° |
α = 104.92 (3)° | µ = 0.12 mm−1 |
β = 106.32 (3)° | T = 150 K |
γ = 104.40 (3)° | Prismatic, colorless |
V = 546.71 (19) Å3 | 0.3 × 0.3 × 0.3 mm |
BRUKER SMART diffractometer | 2225 independent reflections |
Radiation source: fine-focus sealed tube | 1991 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.036 |
Detector resolution: 8 pixels mm-1 | θmax = 26.4°, θmin = 2.2° |
ω scan | h = −7→7 |
Absorption correction: empirical (using intensity measurements) (SADABS; Bruker, 1998) | k = −12→11 |
Tmin = 0.968, Tmax = 0.968 | l = −13→12 |
5585 measured reflections |
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)] = 0.045 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.134 | H-atom parameters constrained |
S = 1.09 | w = 1/[σ2(Fo2) + (0.0837P)2 + 0.1505P] where P = (Fo2 + 2Fc2)/3 |
2225 reflections | (Δ/σ)max < 0.001 |
149 parameters | Δρmax = 0.44 e Å−3 |
0 restraints | Δρmin = −0.31 e Å−3 |
C5H12NO2+·C4H3O4− | γ = 104.40 (3)° |
Mr = 233.22 | V = 546.71 (19) Å3 |
Triclinic, P1 | Z = 2 |
a = 6.1830 (12) Å | Mo Kα radiation |
b = 9.6480 (19) Å | µ = 0.12 mm−1 |
c = 10.534 (2) Å | T = 150 K |
α = 104.92 (3)° | 0.3 × 0.3 × 0.3 mm |
β = 106.32 (3)° |
BRUKER SMART diffractometer | 2225 independent reflections |
Absorption correction: empirical (using intensity measurements) (SADABS; Bruker, 1998) | 1991 reflections with I > 2σ(I) |
Tmin = 0.968, Tmax = 0.968 | Rint = 0.036 |
5585 measured reflections |
R[F2 > 2σ(F2)] = 0.045 | 0 restraints |
wR(F2) = 0.134 | H-atom parameters constrained |
S = 1.09 | Δρmax = 0.44 e Å−3 |
2225 reflections | Δρmin = −0.31 e Å−3 |
149 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 | ||
O1 | 0.84000 (19) | 0.58264 (12) | 0.66233 (12) | 0.0260 (3) | |
H1 | 0.7346 | 0.6207 | 0.6717 | 0.039* | |
O2 | 0.77880 (19) | 0.49747 (12) | 0.83331 (11) | 0.0262 (3) | |
O3 | 0.21319 (19) | 0.07564 (12) | 0.18678 (14) | 0.0319 (3) | |
H3 | 0.2074 | −0.0121 | 0.1430 | 0.048* | |
O4 | 0.49219 (19) | 0.30302 (12) | 0.31668 (12) | 0.0276 (3) | |
O5 | 0.20543 (18) | −0.18088 (12) | 0.07529 (12) | 0.0257 (3) | |
O6 | 0.46732 (18) | −0.29285 (11) | 0.04021 (11) | 0.0246 (3) | |
N1 | 1.1539 (2) | 0.40441 (13) | 0.87416 (12) | 0.0199 (3) | |
H1A | 1.2715 | 0.3636 | 0.8733 | 0.030* | |
H1B | 1.0254 | 0.3350 | 0.8756 | 0.030* | |
H1C | 1.2105 | 0.4901 | 0.9523 | 0.030* | |
C1 | 0.8829 (2) | 0.51190 (15) | 0.75313 (14) | 0.0197 (3) | |
C2 | 1.0790 (2) | 0.44473 (15) | 0.74446 (14) | 0.0193 (3) | |
H2 | 1.2194 | 0.5260 | 0.7478 | 0.023* | |
C3 | 0.9927 (2) | 0.30887 (16) | 0.60556 (15) | 0.0206 (3) | |
H3A | 0.9326 | 0.3456 | 0.5266 | 0.025* | |
C4 | 0.7835 (3) | 0.17424 (17) | 0.59202 (17) | 0.0283 (4) | |
H4A | 0.6532 | 0.2099 | 0.6048 | 0.042* | |
H4B | 0.8384 | 0.1310 | 0.6645 | 0.042* | |
H4C | 0.7251 | 0.0956 | 0.4981 | 0.042* | |
C5 | 1.2001 (3) | 0.25776 (19) | 0.58620 (17) | 0.0283 (4) | |
H5A | 1.3313 | 0.3458 | 0.5954 | 0.042* | |
H5B | 1.1442 | 0.1797 | 0.4923 | 0.042* | |
H5C | 1.2575 | 0.2150 | 0.6586 | 0.042* | |
C6 | 0.4337 (3) | 0.16786 (16) | 0.24253 (15) | 0.0223 (3) | |
C7 | 0.6296 (2) | 0.11276 (16) | 0.21831 (15) | 0.0215 (3) | |
H7 | 0.7831 | 0.1903 | 0.2544 | 0.026* | |
C8 | 0.6235 (2) | −0.02778 (16) | 0.15418 (15) | 0.0215 (3) | |
H8 | 0.7734 | −0.0340 | 0.1518 | 0.026* | |
C9 | 0.4182 (2) | −0.17747 (15) | 0.08529 (14) | 0.0201 (3) |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0286 (6) | 0.0281 (6) | 0.0340 (6) | 0.0151 (4) | 0.0188 (5) | 0.0178 (5) |
O2 | 0.0267 (5) | 0.0329 (6) | 0.0280 (6) | 0.0135 (4) | 0.0175 (5) | 0.0138 (5) |
O3 | 0.0209 (5) | 0.0226 (6) | 0.0538 (7) | 0.0082 (4) | 0.0184 (5) | 0.0101 (5) |
O4 | 0.0275 (6) | 0.0219 (5) | 0.0351 (6) | 0.0101 (4) | 0.0141 (5) | 0.0086 (5) |
O5 | 0.0170 (5) | 0.0226 (5) | 0.0380 (6) | 0.0047 (4) | 0.0123 (4) | 0.0110 (5) |
O6 | 0.0238 (5) | 0.0204 (5) | 0.0289 (6) | 0.0067 (4) | 0.0113 (4) | 0.0067 (4) |
N1 | 0.0186 (6) | 0.0204 (6) | 0.0212 (6) | 0.0066 (4) | 0.0087 (5) | 0.0065 (5) |
C1 | 0.0193 (6) | 0.0167 (6) | 0.0216 (7) | 0.0039 (5) | 0.0086 (5) | 0.0053 (5) |
C2 | 0.0184 (6) | 0.0191 (6) | 0.0223 (7) | 0.0049 (5) | 0.0109 (5) | 0.0083 (5) |
C3 | 0.0209 (7) | 0.0223 (7) | 0.0206 (7) | 0.0078 (5) | 0.0104 (5) | 0.0073 (5) |
C4 | 0.0272 (8) | 0.0235 (7) | 0.0284 (8) | 0.0029 (6) | 0.0128 (6) | 0.0031 (6) |
C5 | 0.0262 (7) | 0.0346 (8) | 0.0282 (8) | 0.0147 (6) | 0.0144 (6) | 0.0087 (6) |
C6 | 0.0219 (7) | 0.0229 (7) | 0.0274 (7) | 0.0082 (5) | 0.0129 (6) | 0.0128 (6) |
C7 | 0.0174 (6) | 0.0219 (7) | 0.0259 (7) | 0.0044 (5) | 0.0100 (5) | 0.0097 (6) |
C8 | 0.0165 (6) | 0.0242 (7) | 0.0268 (7) | 0.0064 (5) | 0.0120 (5) | 0.0098 (6) |
C9 | 0.0197 (7) | 0.0220 (7) | 0.0216 (7) | 0.0062 (5) | 0.0101 (5) | 0.0105 (5) |
O1—C1 | 1.3170 (18) | C3—C5 | 1.5289 (19) |
O1—H1 | 0.84 | C3—C4 | 1.532 (2) |
O2—C1 | 1.2117 (17) | C3—H3A | 1.00 |
O3—C6 | 1.2932 (19) | C4—H4A | 0.98 |
O3—H3 | 0.84 | C4—H4B | 0.98 |
O4—C6 | 1.2343 (19) | C4—H4C | 0.98 |
O5—C9 | 1.2812 (17) | C5—H5A | 0.98 |
O6—C9 | 1.2386 (17) | C5—H5B | 0.98 |
N1—C2 | 1.4967 (18) | C5—H5C | 0.98 |
N1—H1A | 0.91 | C6—C7 | 1.4963 (19) |
N1—H1B | 0.91 | C7—C8 | 1.336 (2) |
N1—H1C | 0.91 | C7—H7 | 0.95 |
C1—C2 | 1.5236 (19) | C8—C9 | 1.502 (2) |
C2—C3 | 1.539 (2) | C8—H8 | 0.95 |
C2—H2 | 1.00 | ||
C1—O1—H1 | 109.5 | C3—C4—H4B | 109.5 |
C6—O3—H3 | 109.5 | H4A—C4—H4B | 109.5 |
C2—N1—H1A | 109.5 | C3—C4—H4C | 109.5 |
C2—N1—H1B | 109.5 | H4A—C4—H4C | 109.5 |
H1A—N1—H1B | 109.5 | H4B—C4—H4C | 109.5 |
C2—N1—H1C | 109.5 | C3—C5—H5A | 109.5 |
H1A—N1—H1C | 109.5 | C3—C5—H5B | 109.5 |
H1B—N1—H1C | 109.5 | H5A—C5—H5B | 109.5 |
O2—C1—O1 | 125.43 (13) | C3—C5—H5C | 109.5 |
O2—C1—C2 | 122.63 (13) | H5A—C5—H5C | 109.5 |
O1—C1—C2 | 111.93 (11) | H5B—C5—H5C | 109.5 |
N1—C2—C1 | 106.47 (11) | O4—C6—O3 | 122.39 (14) |
N1—C2—C3 | 113.72 (11) | O4—C6—C7 | 117.28 (13) |
C1—C2—C3 | 111.40 (11) | O3—C6—C7 | 120.33 (13) |
N1—C2—H2 | 108.4 | C8—C7—C6 | 130.46 (13) |
C1—C2—H2 | 108.4 | C8—C7—H7 | 114.8 |
C3—C2—H2 | 108.4 | C6—C7—H7 | 114.8 |
C5—C3—C4 | 111.08 (12) | C7—C8—C9 | 130.42 (13) |
C5—C3—C2 | 111.31 (12) | C7—C8—H8 | 114.8 |
C4—C3—C2 | 112.87 (12) | C9—C8—H8 | 114.8 |
C5—C3—H3A | 107.1 | O6—C9—O5 | 123.48 (13) |
C4—C3—H3A | 107.1 | O6—C9—C8 | 116.58 (12) |
C2—C3—H3A | 107.1 | O5—C9—C8 | 119.94 (12) |
C3—C4—H4A | 109.5 | ||
O2—C1—C2—N1 | −15.48 (17) | C1—C2—C3—C4 | −63.27 (15) |
O1—C1—C2—N1 | 165.83 (11) | O4—C6—C7—C8 | 173.59 (15) |
O2—C1—C2—C3 | 109.03 (15) | O3—C6—C7—C8 | −6.5 (2) |
O1—C1—C2—C3 | −69.66 (15) | C6—C7—C8—C9 | −0.2 (3) |
N1—C2—C3—C5 | −68.65 (15) | C7—C8—C9—O6 | −176.16 (15) |
C1—C2—C3—C5 | 171.02 (11) | C7—C8—C9—O5 | 4.0 (2) |
N1—C2—C3—C4 | 57.05 (16) |
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···O4i | 0.84 | 1.76 | 2.5963 (15) | 178 |
O3—H3···O5 | 0.84 | 1.60 | 2.4330 (17) | 174 |
N1—H1A···O6ii | 0.91 | 1.99 | 2.8323 (17) | 154 |
N1—H1B···O5iii | 0.91 | 2.07 | 2.9572 (18) | 166 |
N1—H1C···O2iv | 0.91 | 2.21 | 2.8542 (17) | 127 |
N1—H1C···O6v | 0.91 | 2.07 | 2.828 (2) | 140 |
C2—H2···O4vi | 1.00 | 2.48 | 3.453 (2) | 164 |
C7—H7···O1vi | 0.95 | 2.51 | 3.458 (2) | 172 |
C8—H8···O3vii | 0.95 | 2.54 | 3.4229 (19) | 155 |
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) −x+2, −y, −z+1; (iii) −x+1, −y, −z+1; (iv) −x+2, −y+1, −z+2; (v) x+1, y+1, z+1; (vi) −x+2, −y+1, −z+1; (vii) x+1, y, z. |
Experimental details
Crystal data | |
Chemical formula | C5H12NO2+·C4H3O4− |
Mr | 233.22 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 150 |
a, b, c (Å) | 6.1830 (12), 9.6480 (19), 10.534 (2) |
α, β, γ (°) | 104.92 (3), 106.32 (3), 104.40 (3) |
V (Å3) | 546.71 (19) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.12 |
Crystal size (mm) | 0.3 × 0.3 × 0.3 |
Data collection | |
Diffractometer | BRUKER SMART diffractometer |
Absorption correction | Empirical (using intensity measurements) (SADABS; Bruker, 1998) |
Tmin, Tmax | 0.968, 0.968 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 5585, 2225, 1991 |
Rint | 0.036 |
(sin θ/λ)max (Å−1) | 0.625 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.045, 0.134, 1.09 |
No. of reflections | 2225 |
No. of parameters | 149 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.44, −0.31 |
Computer programs: SMART (Bruker, 1999), SMART, SAINT (Bruker, 1999), SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), PLATON (Spek, 1999), SHELXL97.
O1—C1 | 1.3170 (18) | C1—C2 | 1.5236 (19) |
O2—C1 | 1.2117 (17) | C2—C3 | 1.539 (2) |
O3—C6 | 1.2932 (19) | C3—C5 | 1.5289 (19) |
O4—C6 | 1.2343 (19) | C3—C4 | 1.532 (2) |
O5—C9 | 1.2812 (17) | C6—C7 | 1.4963 (19) |
O6—C9 | 1.2386 (17) | C7—C8 | 1.336 (2) |
N1—C2 | 1.4967 (18) | C8—C9 | 1.502 (2) |
O2—C1—O1 | 125.43 (13) | O4—C6—O3 | 122.39 (14) |
O2—C1—C2 | 122.63 (13) | O4—C6—C7 | 117.28 (13) |
O1—C1—C2 | 111.93 (11) | O3—C6—C7 | 120.33 (13) |
N1—C2—C1 | 106.47 (11) | C8—C7—C6 | 130.46 (13) |
N1—C2—C3 | 113.72 (11) | C7—C8—C9 | 130.42 (13) |
C1—C2—C3 | 111.40 (11) | O6—C9—O5 | 123.48 (13) |
C5—C3—C4 | 111.08 (12) | O6—C9—C8 | 116.58 (12) |
C5—C3—C2 | 111.31 (12) | O5—C9—C8 | 119.94 (12) |
C4—C3—C2 | 112.87 (12) | ||
O2—C1—C2—N1 | −15.48 (17) | C1—C2—C3—C4 | −63.27 (15) |
O1—C1—C2—N1 | 165.83 (11) | O4—C6—C7—C8 | 173.59 (15) |
O2—C1—C2—C3 | 109.03 (15) | O3—C6—C7—C8 | −6.5 (2) |
O1—C1—C2—C3 | −69.66 (15) | C6—C7—C8—C9 | −0.2 (3) |
N1—C2—C3—C5 | −68.65 (15) | C7—C8—C9—O6 | −176.16 (15) |
C1—C2—C3—C5 | 171.02 (11) | C7—C8—C9—O5 | 4.0 (2) |
N1—C2—C3—C4 | 57.05 (16) |
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···O4i | 0.84 | 1.76 | 2.5963 (15) | 177.5 |
O3—H3···O5 | 0.84 | 1.60 | 2.4330 (17) | 174.1 |
N1—H1A···O6ii | 0.91 | 1.99 | 2.8323 (17) | 154.1 |
N1—H1B···O5iii | 0.91 | 2.07 | 2.9572 (18) | 165.9 |
N1—H1C···O2iv | 0.91 | 2.21 | 2.8542 (17) | 127.1 |
N1—H1C···O6v | 0.91 | 2.07 | 2.828 (2) | 139.9 |
C2—H2···O4vi | 1.00 | 2.48 | 3.453 (2) | 164.0 |
C7—H7···O1vi | 0.95 | 2.51 | 3.458 (2) | 172.3 |
C8—H8···O3vii | 0.95 | 2.54 | 3.4229 (19) | 154.5 |
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) −x+2, −y, −z+1; (iii) −x+1, −y, −z+1; (iv) −x+2, −y+1, −z+2; (v) x+1, y+1, z+1; (vi) −x+2, −y+1, −z+1; (vii) x+1, y, z. |
Valine [(CH3)2CH—CH(NH2)-COOH, 2-amino-3-methylbutanoic acid] is one of the amino acids, required in the human and animal diet for the maintenance of nitrogen equilibrium. It is also glucogenic. Being hydrophobic with a non-polar hydrocarbon chain, it plays a vital role in the stabilization of the structures of protein molecules. Though crystal structures of complexes of valine with a few inorganic acids are known, structural data on the crystalline complexes of valine with organic acids are scarce. The present study on a complex of DL-valine with maleic acid forms a part of a series of investigations being carried out in our laboratory on crystalline amino acid–carboxylic acid complexes. The crystal structures of glycinium maleate (Rajagopal et al., 2001) and L-alaninium maleate (Alagar, Krishnakumar, Subha Nandhini & Natarajan, 2001) have been reported recently.
Fig. 1 shows the molecular structure with the atom-numbering scheme. The DL-valinium molecule exists in the cationic form with a protonated amino group and an uncharged carboxylic acid group. The maleic acid molecule exists in the mono-ionized state. The semi-maleate ion is essentially planar as observed in the crystal structures of similar complexes. The angle between the planes of the half-molecule is 8.1 (1)°. This value is somewhat larger than that found in L-phenylalaninium maleate [3.5 (1)°; Alagar, Krishnakumar & Natarajan, 2001], where the intramolecular hydrogen bond between atoms O3 and O5 is symmetric. The larger value observed in (I) may be attributed to asymmetric nature of the intramolecular hydrogen bond. An asymmetric intramolecular hydrogen bond is observed in the crystal structures of maleic acid (James & Williams, 1974), glycinium maleate and L-alaninium maleate; it is found to be symmetric in the crystal structures of complexes of maleic acid with DL– and L-arginine (Ravishankar et al., 1998) and L-histidine and L-lysine (Pratap et al., 2000) with an H atom shared between the respective oxygen atoms.
Fig. 2 shows the packing of the molecules of (I) viewed down the a axis. The semi-maleate ions do not have direct hydrogen-bonded interactions among themselves except for a weak C—H···O hydrogen bond which links them to form an infinite one-dimensional chain down the a axis. There is a head-to-tail hydrogen bond among the centrosymmetrically related amino acid molecules leading to the formation of a dimer. The non-polar side chains of the DL-valinium cations form alternating hydrophobic columns down the a axis. The crystal packing is characterized by O—H···O and N—H···O hydrogen bonds. However, considering the presence of many strong O—H···O and N—H···O bonds, it seems unlikely that weak hydrogen bonds of the type C—H···O play a role in determining the packing modes of the molecules. The aggregation pattern has some similarities with that observed in L-phenylalaninium maleate, but is distinctly different from glycinium maleate and L-alaninium maleate.