Zwitterionic 2-(methyl­amino)­ethane­sulfonic acid

The title compound, N-methyl­taurine, C₃H₉NO₃S, was isolated from the marine sponge Xestospongia pacifica from Swain Reefs, Queensland. The crystal structure displays extensive N—H...O hydrogen bonding interactions between the amine H atoms and sulfonyl O atoms in the zwitterionic mol­ecule.

Key indicators

• Single-crystal X-ray study
• T = 295 K
• R factor = 0.031
• wR factor = 0.085
• Data-to-parameter ratio = 11.1

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

General Notes



REFLT_03
         From the CIF: _diffrn_reflns_theta_max           27.50
         From the CIF: _reflns_number_total                820
         Count of symmetry unique reflns          820
         Completeness (_total/calc)            100.00%
         TEST3: Check Friedels for noncentro structure
         Estimate of Friedel pairs measured         0
         Fraction of Friedel pairs measured     0.000
         Are heavy atom types Z>Si present          yes
          WARNING: Large fraction of Friedel related reflns may
                   be needed to determine absolute structure

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S1. Comment

Molecules of 2-(methylamino)ethanesulfonic acid, (I), crystallize in the zwitterionic form with the carboxyl proton transferred to the N atom (Fig. 1 and Table 1). The bond lengths and angles of the molecules are in accord with conventional values (Allan et al., 1987) and related structures (Görbitz et al., 2000).

In the crystal structure, the molecules are linked via a number of N–H···O hydrogen bonds to form a three-dimensional network (Table 2).

In a recent study, N-methyltaurine is reported to be a major osmolyte in a specimen of the tubeworm Lamellibrachia sp. (Yin et al., 2000). Osmolytes are small organic molecules that regulate cell volume by countering osmotic pressure exerted by sea water and it seems reasonable to assume that N-methyltaurine performs a similar role in Xestospongia pacifica.

S2. Experimental

Compound (I) was isolated from the methanol extract of the marine sponge Xestospongia pacifica from Swain Reefs, Queensland. The extract was subjected to repeated gel-permeation chromatography on Sephadex LH-20 in methanol. Crystals of (I) were obtained on slow evaporation of the methanol from the parent fraction; m.p. 520 K (with decomposition). δ_H (400 MHz, DMSO-d₆, p.p.m.): 4.1 (2H, brs, NH₂), 3.16 (3H, s, N–CH₃), 3.14 (2H, t, J_2,1 = 6.4 Hz, H2), 2.77 (2H, t, J_1,2 = 6.4 Hz, H1), (ESMS+): 161.8 (MNa⁺), (ESMS–) 137.8 (M—H).

S3. Refinement

H atoms were constrained as riding atoms, fixed to their parent C atoms at a C–H distance of 0.95 Å. U_iso(H) values were set to 1.2U_eq for the parent atom.

Computing details

Data collection: MSC/AFC7 Diffractometer Control Software (Molecular Structure Corporation, 1999); cell refinement: MSC/AFC7 Diffractometer Control Software; data reduction: TEXSAN (Molecular Structure Corporation, 1997-2001); program(s) used to solve structure: TEXSAN; program(s) used to refine structure: TEXSAN and SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 1980-2001) and ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: TEXSAN and PLATON.

Figures

Fig. 1. ORTEP-3 (Farrugia, 1997) plot showing the atomic numbering scheme for the molecule in the asymmetric unit of (I). Displacement ellipsoids for non-H atoms are drawn at the 30% probability level.

2-(methylamino)ethanesulfonic acid

Crystal data

C3H9NO3S	F(000) = 296
Mr = 139.18	Dx = 1.557 Mg m^−3
Orthorhombic, P212121	Mo Kα radiation, λ = 0.7107 Å
Hall symbol: P 2ac 2ab	Cell parameters from 25 reflections
a = 9.061 (3) Å	θ = 12.9–17.3°
b = 11.931 (3) Å	µ = 0.46 mm^−1
c = 5.4924 (15) Å	T = 295 K
V = 593.8 (3) Å^3	Prismatic, colorless
Z = 4	0.40 × 0.40 × 0.15 mm

Data collection

Rigaku AFC-7R diffractometer	793 reflections with I > 2σ(I)
Radiation source: Rigaku rotating anode	Rint = 0.052
Graphite monochromator	θmax = 27.5°, θmin = 2.8°
ω–2θ scans	h = −11→5
Absorption correction: ψ scan (North et al., 1968)	k = 0→15
Tmin = 0.836, Tmax = 0.934	l = −3→7
1011 measured reflections	3 standard reflections every 150 reflections
820 independent reflections	intensity decay: 0.3%

Refinement

Refinement on F^2	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F^2 > 2σ(F^2)] = 0.031	w = 1/[σ^2(Fo^2) + (0.0546P)^2 + 0.18P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.085	(Δ/σ)max < 0.001
S = 1.06	Δρmax = 0.27 e Å^−3
820 reflections	Δρmin = −0.24 e Å^−3
74 parameters	Extinction correction: SHELXL97, FC^*=KFC[1+0.001XFC^2Λ^3/SIN(2Θ)]^-1/4
0 restraints	Extinction coefficient: 0.154 (12)
Primary atom site location: structure-invariant direct methods	Absolute structure: Flack (1983)
Secondary atom site location: difference Fourier map	Absolute structure parameter: −0.09 (13)

Special details

Experimental. The scan width was (1.79 + 0.30tanθ)° with an ω scan speed of 16° per minute (up to 4 scans to achieve I/σ(I) > 10). Stationary background counts were recorded at each end of the scan, and the scan time:background time ratio was 2:1.

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All e.s.d.'s are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

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
S1	0.43693 (6)	0.14685 (4)	0.65892 (11)	0.0246 (2)
O1	0.4695 (2)	0.02903 (14)	0.7028 (3)	0.0352 (5)
O2	0.4186 (2)	0.16966 (15)	0.3985 (3)	0.0345 (5)
O3	0.5385 (2)	0.22346 (18)	0.7776 (4)	0.0434 (6)
N1	−0.0013 (2)	0.12425 (16)	0.8055 (4)	0.0283 (6)
C1	0.2625 (3)	0.17323 (19)	0.7963 (4)	0.0280 (6)
C2	0.1429 (2)	0.10053 (18)	0.6876 (4)	0.0254 (6)
C3	−0.1270 (3)	0.0623 (2)	0.6983 (5)	0.0370 (8)
H1	0.26920	0.15830	0.96600	0.0340*
H2	0.23730	0.24990	0.77280	0.0340*
H3	0.16740	0.02380	0.71070	0.0310*
H4	0.13530	0.11560	0.51780	0.0310*
H5	0.00520	0.10670	0.95570	0.0340*
H6	−0.01880	0.19410	0.79380	0.0340*
H7	−0.21470	0.07870	0.78630	0.0450*
H8	−0.13910	0.08380	0.53300	0.0450*
H9	−0.10800	−0.01610	0.70630	0.0450*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S1	0.0246 (3)	0.0251 (3)	0.0241 (3)	−0.0024 (2)	0.0023 (2)	−0.0027 (2)
O1	0.0403 (10)	0.0305 (8)	0.0347 (10)	0.0088 (7)	0.0035 (8)	0.0033 (7)
O2	0.0455 (11)	0.0326 (8)	0.0253 (8)	−0.0011 (8)	0.0048 (8)	0.0053 (7)
O3	0.0315 (9)	0.0519 (11)	0.0469 (11)	−0.0144 (9)	0.0029 (9)	−0.0189 (10)
N1	0.0245 (9)	0.0322 (10)	0.0283 (11)	0.0004 (8)	0.0018 (9)	−0.0025 (9)
C1	0.0254 (10)	0.0283 (10)	0.0302 (11)	0.0007 (9)	0.0052 (9)	−0.0081 (9)
C2	0.0242 (9)	0.0264 (9)	0.0256 (11)	−0.0001 (8)	0.0023 (10)	−0.0030 (9)
C3	0.0262 (11)	0.0404 (13)	0.0444 (16)	−0.0051 (10)	−0.0047 (12)	0.0019 (13)

Geometric parameters (Å, º)

S1—O1	1.4564 (18)	C1—C2	1.511 (3)
S1—O2	1.4654 (18)	C1—H1	0.9509
S1—O3	1.452 (2)	C1—H2	0.9516
S1—C1	1.779 (3)	C2—H3	0.9505
N1—C2	1.485 (3)	C2—H4	0.9523
N1—C3	1.480 (3)	C3—H7	0.9505
N1—H5	0.8532	C3—H8	0.9498
N1—H6	0.8508	C3—H9	0.9521
S1···H6^i	3.1535	C2···O1^iii	3.243 (3)
O1···C2^ii	3.243 (3)	C2···O1^ii	3.381 (3)
O1···N1^iii	2.862 (3)	C3···O1^iii	3.260 (3)
O1···C2^iii	3.381 (3)	C3···O1^ii	3.302 (3)
O1···C3^iii	3.302 (3)	C3···O2^vii	3.268 (3)
O1···C3^ii	3.260 (3)	H1···O2^ix	2.7375
O2···C3^i	3.268 (3)	H1···H5	2.4707
O2···N1^i	2.798 (3)	H1···O3^viii	2.8884
O3···N1^iv	2.945 (3)	H2···H6	2.4169
O3···C1^iv	3.334 (3)	H3···O1	2.7384
O1···H3	2.7384	H3···H9	2.5405
O1···H8^ii	2.7318	H3···O2^ii	2.6455
O1···H4^ii	2.6216	H4···O2	2.7267
O1···H5^iii	2.1253	H4···H8	2.5165
O2···H1^v	2.7375	H4···O1^iii	2.6216
O2···H9^iii	2.7233	H4···O3^vii	2.6625
O2···H6^i	2.0198	H5···H1	2.4707
O2···H4	2.7267	H5···O1^ii	2.1253
O2···H3^iii	2.6455	H5···O3^viii	2.5185
O3···H7^vi	2.8260	H6···H2	2.4169
O3···H1^iv	2.8884	H6···S1^vii	3.1535
O3···H4^i	2.6625	H6···O2^vii	2.0198
O3···H5^iv	2.5185	H6···O3^viii	2.6036
O3···H6^iv	2.6036	H7···O3^x	2.8260
N1···O1^ii	2.862 (3)	H8···H4	2.5165
N1···O2^vii	2.798 (3)	H8···O1^iii	2.7318
N1···O3^viii	2.945 (3)	H9···H3	2.5405
C1···O3^viii	3.334 (3)	H9···O2^ii	2.7233
O1—S1—O2	111.33 (10)	S1—C1—H2	109.00
O1—S1—O3	113.89 (11)	C2—C1—H1	109.00
O1—S1—C1	106.29 (11)	C2—C1—H2	109.03
O2—S1—O3	113.15 (12)	H1—C1—H2	109.17
O2—S1—C1	106.28 (11)	N1—C2—H3	109.31
O3—S1—C1	105.15 (11)	N1—C2—H4	109.11
C2—N1—C3	114.10 (19)	C1—C2—H3	109.43
C2—N1—H6	108.52	C1—C2—H4	109.29
C3—N1—H5	108.38	H3—C2—H4	109.24
C2—N1—H5	108.30	N1—C3—H7	109.77
H5—N1—H6	109.05	N1—C3—H8	109.53
C3—N1—H6	108.41	N1—C3—H9	109.46
S1—C1—C2	111.59 (15)	H7—C3—H8	109.51
N1—C2—C1	110.44 (18)	H7—C3—H9	109.27
S1—C1—H1	109.01	H8—C3—H9	109.29
O1—S1—C1—C2	−59.98 (18)	C3—N1—C2—C1	175.97 (19)
O2—S1—C1—C2	58.72 (18)	S1—C1—C2—N1	180.00 (15)
O3—S1—C1—C2	178.94 (16)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H5···O1^ii	0.85	2.13	2.862 (3)	144
N1—H5···O3^viii	0.85	2.52	2.945 (3)	112
N1—H6···O2^vii	0.85	2.02	2.798 (3)	152

Symmetry codes: (ii) −x+1/2, −y, z+1/2; (vii) x−1/2, −y+1/2, −z+1; (viii) x−1/2, −y+1/2, −z+2.