D-Alanine alaninium bromide

The title compound, C₃H₇NO₂⁺_.Br⁻·C₃H₈NO₂, crystallizes from an aqueous solution of D-alanine and racemic 2,3-dibromo­succinic acid. The structure includes alaninium cations and neutral zwitterionic alanine, and displays N—H...Br, N—H...O and O—H...O hydrogen bonding.

Key indicators

• Single-crystal X-ray study
• T = 299 K
• Mean [sigma](C-C) = 0.010 Å
• R factor = 0.054
• wR factor = 0.134
• Data-to-parameter ratio = 19.7

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for         C1
PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor ....       2.48
PLAT341_ALERT_3_C Low Bond Precision on C-C bonds (x 1000) Ang ...         10

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               2422
           Count of symmetry unique reflns         1402
           Completeness (_total/calc)            172.75%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured      1020
           Fraction of Friedel pairs measured     0.728
           Are heavy atom types Z>Si present        yes
PLAT791_ALERT_1_G Confirm the Absolute Configuration of C2     = .          R
PLAT791_ALERT_1_G Confirm the Absolute Configuration of C5     = .          R

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

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   2 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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Computing details

Data collection: COLLECT (Nonius, 1999); cell refinement: DIRAX/LSQ (Duisenberg, 1992); data reduction: EVALCCD (Duisenberg et al., 2003); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 2006); software used to prepare material for publication: maXus (Mackay et al., 1999).

(I)

Crystal data

C3H7NO2^+·Br^−·C3H8NO2	F(000) = 264
Mr = 259.10	Dx = 1.561 Mg m^−3
Monoclinic, P21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2yb	Cell parameters from 27 reflections
a = 9.485 (4) Å	θ = 4.3–16.8°
b = 5.1678 (6) Å	µ = 3.72 mm^−1
c = 11.258 (2) Å	T = 299 K
β = 92.97 (3)°	Plate, colourless
V = 551.1 (3) Å^3	0.31 × 0.19 × 0.06 mm
Z = 2

Data collection

Bruker-Nonius KappaCCD diffractometer	2127 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.070
φ and ω scans	θmax = 27.5°, θmin = 4.6°
Absorption correction: numerical (HABITUS; Herrendorf & Bärnighausen, 1997)	h = −11→12
Tmin = 0.378, Tmax = 0.774	k = −6→6
6831 measured reflections	l = −14→13
2422 independent reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	H-atom parameters constrained
R[F^2 > 2σ(F^2)] = 0.054	w = 1/[σ^2(Fo^2) + (0.0377P)^2 + 1.5036P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.134	(Δ/σ)max < 0.001
S = 1.15	Δρmax = 0.80 e Å^−3
2422 reflections	Δρmin = −0.49 e Å^−3
123 parameters	Absolute structure: Flack (1983), 1033 Friedel pairs
1 restraint	Absolute structure parameter: 0.07 (3)
Primary atom site location: structure-invariant direct methods

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
Br1	0.30824 (6)	0.24804 (16)	0.65061 (5)	0.0475 (2)
C1	0.2961 (8)	0.4423 (13)	0.3014 (6)	0.0426 (15)
C2	0.2671 (7)	0.7095 (18)	0.3559 (5)	0.045 (2)
C3	0.1155 (8)	0.737 (4)	0.3899 (9)	0.083 (3)
C4	0.7013 (8)	0.4852 (14)	−0.0120 (6)	0.0431 (15)
C5	0.7259 (6)	0.248 (2)	0.0634 (4)	0.0407 (11)
C6	0.8735 (7)	0.248 (3)	0.1252 (8)	0.074 (3)
N1	0.3645 (5)	0.745 (2)	0.4608 (4)	0.0436 (10)
N2	0.6168 (5)	0.240 (2)	0.1526 (4)	0.0432 (11)
O1	0.3885 (6)	0.3025 (10)	0.3425 (4)	0.0549 (16)
O2	0.2118 (9)	0.4015 (13)	0.2112 (6)	0.081 (2)
O3	0.7856 (7)	0.5019 (11)	−0.0974 (5)	0.0641 (16)
O4	0.6099 (6)	0.6398 (10)	0.0104 (4)	0.0517 (12)
H1A	0.3446	0.6296	0.5163	0.065*
H1B	0.3549	0.9039	0.4895	0.065*
H1C	0.4529	0.7220	0.4400	0.065*
H2	0.2867	0.8432	0.2973	0.054*
H2A	0.6351	0.3614	0.2074	0.065*
H2B	0.6173	0.0854	0.1870	0.065*
H2C	0.5324	0.2694	0.1169	0.065*
H2D	0.2097	0.2462	0.1962	0.122*
H3A	0.0840	0.5765	0.4223	0.124*
H3B	0.0570	0.7806	0.3206	0.124*
H3C	0.1093	0.8713	0.4483	0.124*
H5	0.7158	0.0949	0.0126	0.049*
H6A	0.8945	0.4168	0.1567	0.111*
H6B	0.9418	0.2023	0.0688	0.111*
H6C	0.8766	0.1238	0.1888	0.111*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br1	0.0667 (4)	0.0399 (3)	0.0367 (3)	0.0003 (5)	0.0099 (2)	−0.0060 (4)
C1	0.066 (4)	0.035 (3)	0.027 (3)	−0.002 (3)	0.007 (3)	−0.012 (3)
C2	0.065 (4)	0.038 (6)	0.030 (3)	0.002 (3)	−0.001 (2)	−0.002 (3)
C3	0.058 (4)	0.095 (7)	0.095 (6)	0.023 (8)	−0.008 (4)	−0.045 (9)
C4	0.057 (4)	0.037 (3)	0.035 (3)	−0.005 (3)	−0.006 (3)	−0.001 (3)
C5	0.055 (3)	0.035 (2)	0.032 (2)	0.005 (6)	0.005 (2)	0.003 (5)
C6	0.050 (4)	0.094 (6)	0.077 (5)	0.007 (8)	0.000 (4)	0.044 (8)
N1	0.054 (3)	0.036 (2)	0.042 (2)	−0.006 (5)	0.0042 (19)	−0.005 (4)
N2	0.051 (2)	0.045 (3)	0.034 (2)	−0.006 (5)	−0.0014 (18)	0.008 (4)
O1	0.067 (3)	0.046 (5)	0.051 (3)	0.007 (2)	0.000 (2)	−0.013 (2)
O2	0.127 (6)	0.055 (4)	0.060 (4)	0.020 (4)	−0.025 (4)	−0.030 (3)
O3	0.097 (4)	0.051 (3)	0.046 (3)	0.011 (3)	0.022 (3)	0.019 (2)
O4	0.063 (3)	0.041 (2)	0.050 (3)	0.005 (2)	−0.004 (2)	0.009 (2)

Geometric parameters (Å, º)

N1—C2	1.472 (8)	C5—H5	0.980
C5—N2	1.479 (6)	N2—H2A	0.890
C5—C4	1.500 (12)	N2—H2B	0.890
C5—C6	1.530 (9)	N2—H2C	0.890
O1—C1	1.209 (9)	C6—H6A	0.960
C2—C3	1.514 (10)	C6—H6B	0.960
C2—C1	1.541 (11)	C6—H6C	0.960
O3—C4	1.284 (9)	C2—H2	0.980
O2—C1	1.277 (9)	O2—H2D	0.820
O4—C4	1.216 (9)	C3—H3A	0.960
N1—H1A	0.890	C3—H3B	0.960
N1—H1B	0.890	C3—H3C	0.960
N1—H1C	0.890
N2—C5—C4	108.3 (7)	C5—N2—H2B	109.5
N2—C5—C6	110.3 (5)	H2A—N2—H2B	109.5
C4—C5—C6	111.8 (9)	C5—N2—H2C	109.5
N1—C2—C3	110.5 (6)	H2A—N2—H2C	109.5
N1—C2—C1	108.2 (7)	H2B—N2—H2C	109.5
C3—C2—C1	112.1 (8)	C5—C6—H6A	109.5
O4—C4—O3	126.2 (7)	C5—C6—H6B	109.5
O4—C4—C5	120.6 (6)	H6A—C6—H6B	109.5
O3—C4—C5	113.2 (6)	C5—C6—H6C	109.5
O1—C1—O2	128.1 (6)	H6A—C6—H6C	109.5
O1—C1—C2	121.6 (6)	H6B—C6—H6C	109.5
O2—C1—C2	110.3 (6)	N1—C2—H2	108.6
C2—N1—H1A	109.5	C3—C2—H2	108.6
C2—N1—H1B	109.5	C1—C2—H2	108.6
H1A—N1—H1B	109.5	C1—O2—H2D	109.5
C2—N1—H1C	109.5	C2—C3—H3A	109.5
H1A—N1—H1C	109.5	C2—C3—H3B	109.5
H1B—N1—H1C	109.5	H3A—C3—H3B	109.5
N2—C5—H5	108.8	C2—C3—H3C	109.5
C4—C5—H5	108.8	H3A—C3—H3C	109.5
C6—C5—H5	108.8	H3B—C3—H3C	109.5
C5—N2—H2A	109.5

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···Br1	0.89	2.52	3.399 (9)	170
N1—H1B···Br1^i	0.89	2.59	3.426 (9)	156
N1—H1C···Br1^ii	0.89	2.54	3.408 (5)	167
N2—H2A···Br1^ii	0.89	2.60	3.484 (9)	174
N2—H2B···Br1^iii	0.89	2.60	3.424 (8)	155
N2—H2C···O4^iv	0.89	2.03	2.802 (7)	144
O2—H2D···O3^iv	0.82	1.69	2.431 (8)	150

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