(S)-2-Carb­oxy­ethyl L-cysteinyl sulfone

The title compound {systematic name: (2S)-2-aza­niumyl-3-[(2-carb­oxy­ethane)­sulfon­yl]propano­ate}, C₆H₁₁NO₆S, forms enanti­opure crystals in the monoclinic space group P2₁ and exists as a zwitterion, with a protonated α-amino group and a deprotonated α-carboxyl group. Both the carboxyl groups and the amino group are involved in an extensive multicentered inter­molecular hydrogen-bonding scheme. In the crystal, the diperiodic network of hydrogen bonds propagates parallel to (101) and involves inter­connected heterodromic R₄³(10) rings. Electrostatic forces are major contributors to the structure energy, which was estimated by DFT calculations as E_total = −333.5 kJ mol⁻¹.

Key indicators

Structure: I

• Single-crystal X-ray study
• T = 100 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.019
• wR factor = 0.051
• Data-to-parameter ratio = 16.6

checkCIF/PLATON results

No syntax errors found



Alert level G
PLAT432_ALERT_2_G Short Inter X...Y Contact  O3       ..C6       .       2.95 Ang.
                                                    1+x,y,z  =      1_655 Check
PLAT432_ALERT_2_G Short Inter X...Y Contact  O3       ..C5       .       3.00 Ang.
                                                    1+x,y,z  =      1_655 Check
PLAT480_ALERT_4_G Long H...A H-Bond Reported H1A      ..O4       .       2.61 Ang.
PLAT795_ALERT_4_G C-Atom in CIF Coordinate List Out-of-Sequence ..         C4 Note
PLAT796_ALERT_4_G O-Atom in CIF Coordinate List Out-of-Sequence ..         O4 Note
PLAT802_ALERT_4_G CIF Input Record(s) with more than 80 Characters          1 Info
PLAT969_ALERT_5_G The 'Henn et al.' R-Factor-gap value ...........       4.63 Note
              Predicted wR2: Based on SigI   2  1.10 or SHELX Weight  4.76       
PLAT978_ALERT_2_G Number C-C Bonds with Positive Residual Density.          4 Info

   0 ALERT level A = Most likely a serious problem - resolve or explain
   0 ALERT level B = A potentially serious problem, consider carefully
   0 ALERT level C = Check. Ensure it is not caused by an omission or oversight
   8 ALERT level G = General information/check it is not something unexpected

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

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Computing details

(2S)-2-Azaniumyl-3-[(2-carboxyethane)sulfonyl]propanoate

Crystal data

C6H11NO6S	F(000) = 236
Mr = 225.22	Dx = 1.724 Mg m^−3
Monoclinic, P21	Mo Kα radiation, λ = 0.71073 Å
a = 4.8838 (2) Å	Cell parameters from 9939 reflections
b = 18.3867 (7) Å	θ = 3.3–30.6°
c = 5.1522 (2) Å	µ = 0.38 mm^−1
β = 110.3246 (16)°	T = 100 K
V = 433.85 (3) Å^3	Plate, colourless
Z = 2	0.45 × 0.28 × 0.02 mm

Data collection

Bruker APEXII area detector diffractometer	2656 independent reflections
Radiation source: Sealed Source Mo with TRIUMPH optics	2644 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.017
ω and phi scans	θmax = 30.6°, θmin = 2.2°
Absorption correction: multi-scan (AXScale; Bruker, 2014)	h = −6→6
Tmin = 0.705, Tmax = 0.746	k = −26→26
15133 measured reflections	l = −7→7

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: mixed
R[F^2 > 2σ(F^2)] = 0.019	Only H-atom coordinates refined
wR(F^2) = 0.051	w = 1/[σ^2(Fo^2) + (0.0333P)^2 + 0.0609P] where P = (Fo^2 + 2Fc^2)/3
S = 1.10	(Δ/σ)max = 0.001
2656 reflections	Δρmax = 0.31 e Å^−3
160 parameters	Δρmin = −0.18 e Å^−3
1 restraint	Absolute structure: Flack x determined using 1277 quotients [(I^+)-(I^-)]/[(I^+)+(I^-)] (Parsons et al., 2013)
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: −0.001 (11)

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Refinement. Data were corrected for Lorentz, polarization, and absorption effects. Non-hydrogen atoms were refined with anisotropic thermal parameters. The hydroxyl and ammonium hydrogen atoms were located in difference Fourier maps and were allowed to refine freely. The remaining H atoms were placed at calculated positions and included in the refinement using a riding model. All hydrogen atom thermal parameters were constrained to ride on the carrier atoms (U_iso(methine, methylene H) = 1.2U_eq and U_iso(hydroxyl, ammonium H) = 1.5U_eq).

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
S1	0.85411 (6)	0.89496 (2)	0.84809 (6)	0.01103 (8)
O6	0.1220 (2)	0.69175 (6)	0.5230 (2)	0.01356 (19)
H6	0.006 (6)	0.6645 (14)	0.561 (5)	0.020*
O4	1.0462 (3)	0.92863 (7)	1.0965 (3)	0.0239 (3)
O5	0.2537 (2)	0.72208 (6)	0.9711 (2)	0.0144 (2)
C1	0.4393 (3)	1.06770 (7)	0.3928 (3)	0.0085 (2)
C6	0.2813 (3)	0.72813 (7)	0.7474 (3)	0.0100 (2)
O2	0.2657 (2)	1.09831 (6)	0.4873 (2)	0.0141 (2)
N1	0.8143 (3)	1.07575 (6)	0.8579 (2)	0.0091 (2)
H1A	0.998 (5)	1.0653 (13)	0.951 (5)	0.014*
H1B	0.801 (5)	1.1210 (14)	0.816 (4)	0.014*
H1C	0.707 (5)	1.0726 (13)	0.957 (5)	0.014*
O1	0.4180 (2)	1.06328 (6)	0.14494 (19)	0.01234 (18)
C4	0.6697 (3)	0.82185 (7)	0.9387 (3)	0.0115 (2)
H4A	0.818 (5)	0.7954 (13)	1.063 (4)	0.014*
H4B	0.548 (5)	0.8430 (13)	1.023 (4)	0.014*
C3	0.5730 (3)	0.95792 (7)	0.6791 (3)	0.0095 (2)
C2	0.6965 (3)	1.02859 (7)	0.6080 (2)	0.0076 (2)
H2	0.854 (5)	1.0212 (12)	0.541 (4)	0.009*
O3	0.9803 (3)	0.87027 (6)	0.6484 (3)	0.0207 (2)
C5	0.4975 (3)	0.77739 (7)	0.6867 (3)	0.0117 (2)
H5A	0.395 (5)	0.8068 (13)	0.533 (4)	0.014*
H5B	0.618 (5)	0.7471 (14)	0.621 (4)	0.014*
H3A	0.445 (5)	0.9346 (13)	0.517 (5)	0.014*
H3B	0.459 (5)	0.9664 (12)	0.797 (5)	0.014*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S1	0.00737 (13)	0.00812 (13)	0.01511 (13)	−0.00088 (11)	0.00073 (9)	0.00364 (11)
O6	0.0136 (4)	0.0127 (4)	0.0158 (4)	−0.0061 (4)	0.0068 (4)	−0.0039 (3)
O4	0.0206 (6)	0.0166 (5)	0.0208 (5)	−0.0083 (4)	−0.0100 (4)	0.0045 (4)
O5	0.0184 (5)	0.0110 (5)	0.0152 (4)	−0.0032 (4)	0.0075 (4)	0.0006 (3)
C1	0.0077 (5)	0.0071 (5)	0.0096 (5)	−0.0006 (4)	0.0017 (4)	0.0009 (4)
C6	0.0097 (5)	0.0064 (5)	0.0143 (5)	0.0000 (4)	0.0047 (4)	−0.0005 (4)
O2	0.0130 (5)	0.0164 (5)	0.0130 (4)	0.0072 (4)	0.0046 (4)	0.0016 (4)
N1	0.0088 (5)	0.0086 (5)	0.0088 (4)	−0.0004 (4)	0.0015 (4)	−0.0006 (3)
O1	0.0106 (4)	0.0180 (5)	0.0079 (4)	−0.0008 (4)	0.0025 (3)	0.0012 (4)
C4	0.0118 (6)	0.0088 (5)	0.0129 (5)	−0.0024 (4)	0.0028 (4)	0.0025 (4)
C3	0.0074 (5)	0.0071 (5)	0.0122 (5)	−0.0001 (4)	0.0011 (4)	0.0008 (4)
C2	0.0079 (5)	0.0066 (5)	0.0077 (4)	0.0002 (4)	0.0019 (4)	0.0000 (4)
O3	0.0186 (5)	0.0143 (5)	0.0356 (6)	0.0035 (4)	0.0177 (5)	0.0059 (4)
C5	0.0119 (5)	0.0093 (5)	0.0157 (5)	−0.0025 (5)	0.0072 (4)	−0.0016 (4)

Geometric parameters (Å, º)

S1—O4	1.4380 (12)	C3—C2	1.5293 (18)
S1—C4	1.7686 (13)	O6—H6	0.83 (3)
S1—C3	1.7756 (13)	N1—H1A	0.88 (3)
S1—O3	1.4440 (12)	N1—H1B	0.86 (3)
O6—C6	1.3285 (16)	N1—H1C	0.85 (3)
O5—C6	1.2107 (16)	C2—H2	0.96 (2)
C1—O2	1.2489 (16)	C3—H3A	0.95 (2)
C1—O1	1.2471 (15)	C3—H3B	0.97 (3)
C1—C2	1.5353 (18)	C4—H4A	0.92 (2)
C6—C5	1.5038 (19)	C4—H4B	0.93 (2)
N1—C2	1.4919 (16)	C5—H5A	0.95 (2)
C4—C5	1.5174 (19)	C5—H5B	0.95 (2)
O4—S1—C4	109.09 (7)	H1A—N1—H1B	109 (2)
O4—S1—C3	108.07 (7)	H1A—N1—H1C	113 (2)
O4—S1—O3	117.48 (9)	H1B—N1—H1C	102 (2)
C4—S1—C3	104.31 (6)	N1—C2—H2	106.1 (13)
O3—S1—C4	109.37 (7)	C1—C2—H2	111.4 (12)
O3—S1—C3	107.71 (7)	C3—C2—H2	113.5 (13)
O2—C1—C2	115.16 (11)	S1—C3—H3A	107.2 (15)
O1—C1—O2	127.01 (13)	S1—C3—H3B	108.2 (14)
O1—C1—C2	117.75 (12)	C2—C3—H3A	111.4 (15)
O6—C6—C5	111.32 (11)	C2—C3—H3B	112.0 (13)
O5—C6—O6	123.82 (13)	H3A—C3—H3B	106 (2)
O5—C6—C5	124.85 (12)	S1—C4—H4A	103.6 (15)
C5—C4—S1	111.44 (9)	S1—C4—H4B	105.7 (15)
C2—C3—S1	111.67 (9)	C5—C4—H4A	112.3 (14)
N1—C2—C1	108.94 (10)	C5—C4—H4B	111.7 (14)
N1—C2—C3	110.69 (10)	H4A—C4—H4B	111.7 (19)
C3—C2—C1	106.21 (10)	C4—C5—H5A	112.5 (14)
C6—C5—C4	111.54 (11)	C4—C5—H5B	113.0 (14)
C6—O6—H6	109.9 (17)	C6—C5—H5A	108.2 (15)
C2—N1—H1A	111.0 (16)	C6—C5—H5B	106.7 (15)
C2—N1—H1B	112.0 (13)	H5A—C5—H5B	104.4 (19)
C2—N1—H1C	110.2 (16)
O3—S1—C3—C2	−69.00 (11)	O2—C1—C2—H2	−159.7 (14)
O4—S1—C3—C2	58.88 (12)	C1—C2—N1—H1A	−155.6 (17)
C4—S1—C3—C2	174.85 (9)	C1—C2—N1—H1B	−33.7 (18)
O3—S1—C4—C5	−41.94 (13)	C1—C2—N1—H1C	79.2 (18)
O4—S1—C4—C5	−171.68 (11)	C3—C2—N1—H1A	88.0 (17)
C3—S1—C4—C5	73.05 (11)	C3—C2—N1—H1B	−150.1 (18)
O1—C1—C2—N1	139.90 (13)	C3—C2—N1—H1C	−37.2 (18)
O1—C1—C2—C3	−100.88 (14)	H2—C2—N1—H1A	−36 (2)
O2—C1—C2—N1	−43.00 (16)	H2—C2—N1—H1B	86 (2)
O2—C1—C2—C3	76.23 (14)	H2—C2—N1—H1C	−161 (2)
N1—C2—C3—S1	−78.37 (13)	N1—C2—C3—H3A	161.7 (17)
C1—C2—C3—S1	163.54 (9)	N1—C2—C3—H3B	43.1 (16)
S1—C4—C5—C6	−165.17 (10)	C1—C2—C3—H3A	43.7 (17)
C4—C5—C6—O5	−2.7 (2)	C1—C2—C3—H3B	−75.0 (16)
C4—C5—C6—O6	177.18 (12)	H2—C2—C3—S1	40.8 (13)
O3—S1—C3—H3A	53.3 (16)	H2—C2—C3—H3A	−79 (2)
O3—S1—C3—H3B	167.4 (15)	H2—C2—C3—H3B	162 (2)
O4—S1—C3—H3A	−178.8 (16)	S1—C4—C5—H5A	−43.3 (17)
O4—S1—C3—H3B	−64.8 (15)	S1—C4—C5—H5B	74.7 (16)
C4—S1—C3—H3A	−62.8 (16)	H4A—C4—C5—C6	79.1 (16)
C4—S1—C3—H3B	51.2 (15)	H4A—C4—C5—H5A	−159 (2)
O3—S1—C4—H4A	79.0 (14)	H4A—C4—C5—H5B	−41 (2)
O3—S1—C4—H4B	−163.4 (13)	H4B—C4—C5—C6	−47.2 (15)
O4—S1—C4—H4A	−50.8 (14)	H4B—C4—C5—H5A	75 (2)
O4—S1—C4—H4B	66.8 (13)	H4B—C4—C5—H5B	−167 (2)
C3—S1—C4—H4A	−166.1 (14)	H5A—C5—C6—O5	−127.0 (14)
C3—S1—C4—H4B	−48.4 (13)	H5A—C5—C6—O6	52.9 (14)
H6—O6—C6—O5	−1 (2)	H5B—C5—C6—O5	121.2 (13)
H6—O6—C6—C5	179 (2)	H5B—C5—C6—O6	−59.0 (13)
O1—C1—C2—H2	23.2 (14)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O1^i	0.88 (3)	1.95 (3)	2.8113 (17)	168 (2)
N1—H1A···O4	0.88 (3)	2.61 (2)	3.0239 (17)	110 (2)
N1—H1B···O5^ii	0.86 (3)	2.22 (2)	2.8860 (16)	134 (2)
N1—H1B···O6^iii	0.86 (3)	2.31 (2)	2.9869 (15)	136 (2)
N1—H1C···O1^iv	0.85 (3)	1.98 (3)	2.8238 (17)	173 (2)
O6—H6···O2^v	0.83 (3)	1.75 (3)	2.5436 (15)	159 (2)

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