(S)-Alanine-(S)-mandelic acid (1/1)

Crystals of the title molecular complex, C₈H₈O₃·C₃H₇NO₂, were obtained from the remaining filtrate after separating the crystals of a molecular complex of (S)-alanine-(R)-mandelic acid in an optical resolution experiment using (S)-alanine. Each (S)-alanine is hydrogen bonded to three (S)-mandelic acid molecules (and vice versa). The carboxyl­ate of (S)-alanine is nearly coplanar with the carboxyl group of (S)-mandelic acid, a situation that is very different from that found in the reported (S)-alanine-(R)-mandelic acid.

Key indicators

• Single-crystal X-ray study
• T = 295 K
• Mean [sigma](C-C) = 0.005 Å
• R factor = 0.054
• wR factor = 0.154
• Data-to-parameter ratio = 10.9

checkCIF/PLATON results

No syntax errors found



Alert level A
PLAT432_ALERT_2_A Short Inter X...Y Contact  C4A    ..  C5B      =       2.78 Ang.

Author Response: The phenyl group is disordered. The carbon atoms with suffix A, B and C belong to different components of the disordered phenyl group.

PLAT432_ALERT_2_A Short Inter X...Y Contact  C5A    ..  C4B      =       2.75 Ang.

Author Response: The phenyl group is disordered. The carbon atoms with suffix A, B and C belong to different components of the disordered phenyl group.

PLAT432_ALERT_2_A Short Inter X...Y Contact  C5A    ..  C5B      =       2.77 Ang.

Author Response: The phenyl group is disordered. The carbon atoms with suffix A, B and C belong to different components of the disordered phenyl group.

Alert level B
PLAT201_ALERT_2_B Isotropic non-H Atoms in Main Residue(s) ..... =          6
PLAT220_ALERT_2_B Large Non-Solvent    C     Ueq(max)/Ueq(min) ...       3.68 Ratio
PLAT241_ALERT_2_B Check High   U(eq) as Compared to Neighbors ....        C5B
PLAT432_ALERT_2_B Short Inter X...Y Contact  C4B    ..  C5B      =       2.98 Ang.

Author Response: The phenyl group is disordered. The carbon atoms with suffix A, B and C belong to different components of the disordered phenyl group.

PLAT432_ALERT_2_B Short Inter X...Y Contact  C5B    ..  C5B      =       3.01 Ang.

Author Response: The phenyl group is disordered. The carbon atoms with suffix A, B and C belong to different components of the disordered phenyl group.

PLAT432_ALERT_2_B Short Inter X...Y Contact  C5B    ..  C5B      =       3.01 Ang.

Author Response: The phenyl group is disordered. The carbon atoms with suffix A, B and C belong to different components of the disordered phenyl group.

PLAT432_ALERT_2_B Short Inter X...Y Contact  C7B    ..  C7B      =       2.92 Ang.

Author Response: The phenyl group is disordered. The carbon atoms with suffix A, B and C belong to different components of the disordered phenyl group.

Alert level C
PLAT165_ALERT_3_C Nr. of Status R Flagged Non-Hydrogen Atoms .....         18
PLAT222_ALERT_3_C Large Non-Solvent    H     Ueq(max)/Ueq(min) ...       3.58 Ratio
PLAT241_ALERT_2_C Check High   U(eq) as Compared to Neighbors ....        C4C
PLAT241_ALERT_2_C Check High   U(eq) as Compared to Neighbors ....        C5C
PLAT241_ALERT_2_C Check High   U(eq) as Compared to Neighbors ....        C7C
PLAT241_ALERT_2_C Check High   U(eq) as Compared to Neighbors ....        C8B
PLAT242_ALERT_2_C Check Low    U(eq) as Compared to Neighbors ....        C3B
PLAT242_ALERT_2_C Check Low    U(eq) as Compared to Neighbors ....        C6B
PLAT242_ALERT_2_C Check Low    U(eq) as Compared to Neighbors ....        C6C
PLAT250_ALERT_2_C Large U3/U1 ratio for average U(i,j) tensor ....       2.29
PLAT301_ALERT_3_C Main Residue  Disorder .........................      21.00 Perc.
PLAT340_ALERT_3_C Low Bond Precision on C-C bonds (x 1000) Ang ...          5
PLAT432_ALERT_2_C Short Inter X...Y Contact  C4B    ..  C5B      =       3.15 Ang.

Author Response: The phenyl group is disordered. The carbon atoms with suffix A, B and C belong to different components of the disordered phenyl group.

PLAT779_ALERT_2_C Suspect or Irrelevant (Bond) Angle in CIF ......       9.20 Deg.
              C3C  -C2   -C3A     1.555   1.555   1.555
PLAT779_ALERT_2_C Suspect or Irrelevant (Bond) Angle in CIF ......      10.20 Deg.
              C3C  -C2   -C3B     1.555   1.555   1.555
PLAT779_ALERT_2_C Suspect or Irrelevant (Bond) Angle in CIF ......       1.50 Deg.
              C3A  -C2   -C3B     1.555   1.555   1.555

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           27.50
           From the CIF: _reflns_number_total               1484
           Count of symmetry unique reflns         1482
           Completeness (_total/calc)            100.13%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured         2
           Fraction of Friedel pairs measured     0.001
           Are heavy atom types Z>Si present           no

   3 ALERT level A = In general: serious problem
   7 ALERT level B = Potentially serious problem
  16 ALERT level C = Check and explain
   1 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
  22 ALERT type 2 Indicator that the structure model may be wrong or deficient
   4 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1992); cell refinement: MSC/AFC Diffractometer Control Software; data reduction: TEXSAN (Molecular Structure Corporation, 1985); program(s) used to solve structure: SIR2 (Altomare et al., 1993); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

(I)

Crystal data

C8H8O3·C3H7NO2	F(000) = 512
Mr = 241.24	Dx = 1.366 Mg m^−3
Monoclinic, C2	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: C 2y	Cell parameters from 20 reflections
a = 17.795 (4) Å	θ = 5.5–9.8°
b = 5.394 (2) Å	µ = 0.11 mm^−1
c = 12.431 (2) Å	T = 295 K
β = 100.65 (1)°	Prism, colorless
V = 1172.7 (5) Å^3	0.4 × 0.4 × 0.2 mm
Z = 4

Data collection

Rigaku AFC-7S diffractometer	Rint = 0.017
Radiation source: fine-focus sealed tube	θmax = 27.5°, θmin = 1.7°
Graphite monochromator	h = −1→22
ω/2θ scans	k = −7→1
1928 measured reflections	l = −16→15
1484 independent reflections	3 standard reflections every 150 reflections
1276 reflections with I > 2σ(I)	intensity decay: 0.6%

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.054	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.154	H-atom parameters constrained
S = 1.06	w = 1/[σ^2(Fo^2) + (0.0812P)^2 + 1.03P] where P = (Fo^2 + 2Fc^2)/3
1484 reflections	(Δ/σ)max = 0.001
136 parameters	Δρmax = 0.35 e Å^−3
1 restraint	Δρmin = −0.33 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 (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
O1	0.71606 (13)	0.2376 (5)	0.1896 (2)	0.0459 (6)
H1A	0.7121	0.0861	0.1878	0.055*
O2	0.57574 (13)	0.7041 (5)	0.1353 (2)	0.0470 (6)
H2A	0.5431	0.5991	0.1395	0.056*
O3	0.70046 (13)	0.7252 (5)	0.1586 (2)	0.0424 (6)
C1	0.64173 (18)	0.6087 (6)	0.1633 (3)	0.0323 (7)
C2	0.64601 (18)	0.3442 (6)	0.2061 (3)	0.0336 (7)
H2	0.6029	0.2479	0.1665	0.040*
C3A	0.6438 (4)	0.3447 (14)	0.3296 (4)	0.0396 (10)*	0.52
C4A	0.6829 (4)	0.5255 (12)	0.3975 (5)	0.0489 (17)*	0.52
H4A	0.7097	0.6488	0.3684	0.059*	0.52
C5A	0.6820 (4)	0.5220 (13)	0.5091 (4)	0.062 (2)*	0.52
H5A	0.7082	0.6430	0.5545	0.074*	0.52
C6A	0.6420 (5)	0.3377 (16)	0.5527 (4)	0.067 (4)*	0.52
H6A	0.6414	0.3353	0.6273	0.081*	0.52
C7A	0.6029 (4)	0.1569 (14)	0.4847 (6)	0.064 (3)*	0.52
H7A	0.5761	0.0335	0.5139	0.077*	0.52
C8A	0.6038 (4)	0.1604 (13)	0.3731 (6)	0.054 (3)*	0.52
H8A	0.5777	0.0394	0.3277	0.064*	0.52
C3B	0.6455 (9)	0.350 (4)	0.3302 (10)	0.0396 (10)*	0.22
C4B	0.7146 (7)	0.378 (5)	0.4023 (14)	0.093 (8)*	0.22
H4B	0.7601	0.3858	0.3756	0.112*	0.22
C5B	0.7158 (9)	0.396 (6)	0.5141 (13)	0.119 (12)*	0.22
H5B	0.7621	0.4153	0.5623	0.143*	0.22
C6B	0.6479 (11)	0.385 (6)	0.5540 (10)	0.080 (12)*	0.22
H6B	0.6487	0.3971	0.6288	0.096*	0.22
C7B	0.5787 (9)	0.357 (5)	0.4819 (13)	0.085 (7)*	0.22
H7B	0.5333	0.3492	0.5086	0.102*	0.22
C8B	0.5775 (7)	0.339 (4)	0.3701 (12)	0.083 (7)*	0.22
H8B	0.5313	0.3197	0.3219	0.100*	0.22
C3C	0.6308 (9)	0.350 (3)	0.3168 (8)	0.0396 (10)*	0.26
C4C	0.6507 (8)	0.551 (3)	0.3865 (10)	0.074 (5)*	0.26
H4C	0.6707	0.6933	0.3607	0.089*	0.26
C5C	0.6407 (8)	0.538 (3)	0.4946 (10)	0.084 (6)*	0.26
H5C	0.6540	0.6718	0.5412	0.100*	0.26
C6C	0.6108 (9)	0.324 (3)	0.5331 (9)	0.056 (4)*	0.26
H6C	0.6041	0.3155	0.6054	0.067*	0.26
C7C	0.5908 (10)	0.124 (3)	0.4634 (12)	0.084 (8)*	0.26
H7C	0.5708	−0.0191	0.4891	0.101*	0.26
C8C	0.6008 (10)	0.137 (3)	0.3553 (11)	0.069 (7)*	0.26
H8C	0.5875	0.0024	0.3086	0.083*	0.26
O4	0.33578 (14)	0.4495 (5)	0.0742 (2)	0.0455 (7)
O5	0.46148 (14)	0.4403 (5)	0.1211 (3)	0.0507 (7)
N	0.32475 (14)	0.9385 (5)	0.0681 (2)	0.0341 (6)
H3A	0.3271	1.1031	0.0727	0.051*
H3B	0.2882	0.8832	0.1022	0.051*
H3C	0.3142	0.8935	−0.0020	0.051*
C9	0.39752 (18)	0.5525 (6)	0.1028 (3)	0.0327 (7)
C10	0.39911 (17)	0.8317 (6)	0.1203 (3)	0.0317 (7)
H10	0.4398	0.9042	0.0870	0.038*
C11	0.4137 (2)	0.8915 (9)	0.2413 (3)	0.0542 (10)
H11A	0.4260	1.0641	0.2517	0.081*
H11B	0.4556	0.7932	0.2783	0.081*
H11C	0.3687	0.8550	0.2708	0.081*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0432 (13)	0.0249 (12)	0.0753 (16)	0.0072 (11)	0.0258 (11)	0.0048 (13)
O2	0.0320 (11)	0.0319 (12)	0.0777 (16)	0.0038 (11)	0.0122 (10)	0.0099 (14)
O3	0.0356 (12)	0.0256 (12)	0.0698 (15)	−0.0005 (11)	0.0195 (10)	0.0030 (12)
C1	0.0334 (16)	0.0247 (15)	0.0413 (16)	0.0000 (13)	0.0135 (12)	−0.0025 (13)
C2	0.0313 (15)	0.0231 (14)	0.0483 (17)	−0.0013 (13)	0.0121 (12)	0.0002 (14)
O4	0.0329 (12)	0.0208 (11)	0.0810 (18)	−0.0039 (10)	0.0061 (11)	−0.0020 (12)
O5	0.0341 (12)	0.0279 (12)	0.0899 (19)	0.0075 (11)	0.0110 (11)	0.0061 (13)
N	0.0307 (13)	0.0221 (12)	0.0499 (15)	0.0014 (12)	0.0083 (11)	−0.0003 (12)
C9	0.0292 (15)	0.0227 (15)	0.0471 (17)	0.0012 (12)	0.0096 (13)	0.0006 (13)
C10	0.0259 (14)	0.0221 (14)	0.0477 (17)	−0.0010 (12)	0.0088 (12)	−0.0035 (14)
C11	0.057 (2)	0.049 (2)	0.053 (2)	0.0018 (19)	0.0009 (17)	−0.0112 (19)

Geometric parameters (Å, º)

O1—C2	1.422 (4)	C6B—H6B	0.9300
O1—H1A	0.8200	C7B—C8B	1.3900
O2—C1	1.270 (4)	C7B—H7B	0.9300
O2—H2A	0.8200	C8B—H8B	0.9300
O3—C1	1.230 (4)	C3C—C4C	1.3900
C1—C2	1.519 (5)	C3C—C8C	1.3900
C2—C3C	1.451 (10)	C4C—C5C	1.3900
C2—C3A	1.543 (6)	C4C—H4C	0.9300
C2—C3B	1.546 (13)	C5C—C6C	1.3900
C2—H2	0.9800	C5C—H5C	0.9300
C3A—C4A	1.3900	C6C—C7C	1.3900
C3A—C8A	1.3900	C6C—H6C	0.9300
C4A—C5A	1.3900	C7C—C8C	1.3900
C4A—H4A	0.9300	C7C—H7C	0.9300
C5A—C6A	1.3900	C8C—H8C	0.9300
C5A—H5A	0.9300	O4—C9	1.224 (4)
C6A—C7A	1.3900	O5—C9	1.272 (4)
C6A—H6A	0.9300	N—C10	1.479 (4)
C7A—C8A	1.3900	N—H3A	0.8900
C7A—H7A	0.9300	N—H3B	0.8900
C8A—H8A	0.9300	N—H3C	0.8900
C3B—C4B	1.3900	C9—C10	1.521 (4)
C3B—C8B	1.3900	C10—C11	1.514 (5)
C4B—C5B	1.3900	C10—H10	0.9800
C4B—H4B	0.9300	C11—H11A	0.9600
C5B—C6B	1.3900	C11—H11B	0.9600
C5B—H5B	0.9300	C11—H11C	0.9600
C6B—C7B	1.3900
C2—O1—H1A	109.5	C5B—C6B—H6B	120.0
C1—O2—H2A	109.5	C7B—C6B—H6B	120.0
O3—C1—O2	122.0 (3)	C6B—C7B—C8B	120.0
O3—C1—C2	120.5 (3)	C6B—C7B—H7B	120.0
O2—C1—C2	117.4 (3)	C8B—C7B—H7B	120.0
O1—C2—C3C	117.9 (7)	C7B—C8B—C3B	120.0
O1—C2—C1	108.6 (3)	C7B—C8B—H8B	120.0
C3C—C2—C1	107.8 (7)	C3B—C8B—H8B	120.0
O1—C2—C3A	109.1 (4)	C4C—C3C—C8C	120.0
C3C—C2—C3A	9.2 (8)	C4C—C3C—C2	122.5 (10)
C1—C2—C3A	109.7 (4)	C8C—C3C—C2	117.3 (10)
O1—C2—C3B	108.6 (7)	C5C—C4C—C3C	120.0
C3C—C2—C3B	10.2 (9)	C5C—C4C—H4C	120.0
C1—C2—C3B	108.8 (8)	C3C—C4C—H4C	120.0
C3A—C2—C3B	1.5 (8)	C6C—C5C—C4C	120.0
O1—C2—H2	109.8	C6C—C5C—H5C	120.0
C3C—C2—H2	102.8	C4C—C5C—H5C	120.0
C1—C2—H2	109.8	C5C—C6C—C7C	120.0
C3A—C2—H2	109.8	C5C—C6C—H6C	120.0
C3B—C2—H2	111.3	C7C—C6C—H6C	120.0
C4A—C3A—C8A	120.0	C6C—C7C—C8C	120.0
C4A—C3A—C2	120.3 (4)	C6C—C7C—H7C	120.0
C8A—C3A—C2	119.7 (4)	C8C—C7C—H7C	120.0
C3A—C4A—C5A	120.0	C7C—C8C—C3C	120.0
C3A—C4A—H4A	120.0	C7C—C8C—H8C	120.0
C5A—C4A—H4A	120.0	C3C—C8C—H8C	120.0
C6A—C5A—C4A	120.0	C10—N—H3A	109.5
C6A—C5A—H5A	120.0	C10—N—H3B	109.5
C4A—C5A—H5A	120.0	H3A—N—H3B	109.5
C5A—C6A—C7A	120.0	C10—N—H3C	109.5
C5A—C6A—H6A	120.0	H3A—N—H3C	109.5
C7A—C6A—H6A	120.0	H3B—N—H3C	109.5
C6A—C7A—C8A	120.0	O4—C9—O5	124.2 (3)
C6A—C7A—H7A	120.0	O4—C9—C10	118.9 (3)
C8A—C7A—H7A	120.0	O5—C9—C10	116.9 (3)
C7A—C8A—C3A	120.0	N—C10—C11	109.2 (3)
C7A—C8A—H8A	120.0	N—C10—C9	109.4 (3)
C3A—C8A—H8A	120.0	C11—C10—C9	110.4 (3)
C4B—C3B—C8B	120.0	N—C10—H10	109.3
C4B—C3B—C2	118.5 (10)	C11—C10—H10	109.3
C8B—C3B—C2	121.4 (10)	C9—C10—H10	109.3
C3B—C4B—C5B	120.0	C10—C11—H11A	109.5
C3B—C4B—H4B	120.0	C10—C11—H11B	109.5
C5B—C4B—H4B	120.0	H11A—C11—H11B	109.5
C6B—C5B—C4B	120.0	C10—C11—H11C	109.5
C6B—C5B—H5B	120.0	H11A—C11—H11C	109.5
C4B—C5B—H5B	120.0	H11B—C11—H11C	109.5
C5B—C6B—C7B	120.0

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1A···O3^i	0.82	1.98	2.797 (4)	171
O2—H2A···O5	0.82	1.67	2.461 (4)	163
N—H3A···O4^ii	0.89	1.87	2.763 (4)	176
N—H3B···O1^iii	0.89	1.99	2.877 (4)	173
N—H3C···O3^iv	0.89	2.12	3.000 (4)	169

Symmetry codes: (i) x, y−1, z; (ii) x, y+1, z; (iii) x−1/2, y+1/2, z; (iv) −x+1, y, −z.