Bis(β-alaninium) biphenyl-4,4′-disulfonate

In the crystal structure of the title compound, 2C₃H₈NO₂⁺·C₁₂H₈O₆S₂²⁻, N—H...O hydrogen bonds formed between the amino H atoms and the sulfonate O atoms give rise to the assembly of cationic β-alaninium dimers and centrosymmetric bi­phenyl-4,4′-­di­sulfonate anions into an extended two-dimensional layer. The resulting hydrogen-bonded ribbons can be described as C(6)R(12) according to graph-set notation. C—H...O hydrogen bonds between adjacent sheets further extend the structure into a three-dimensional arrangement.

S1. Comment

Sulfonate salts have been used to grow X-ray quality crystals of peptides which were otherwise difficult to obtain, and to study the recognition patterns between the sulfonate and molecules of biological interest (Sudbeck et al., 1994). Detailed hydrogen-bond graph-set analyses have been carried out for three arenesulfonate salts of amino acids (Sudbeck et al., 1995). Here, we present an interesting extended two-dimensional network generated by the hydrogen-bonding interactions between the sulfonate O atoms of 4,4'-biphenyldisulfonate (BPDS) and the amino H atoms of the cationic β-alaninium dimer in the title compound, (I). \sch

The BPDS anion is located on a crystallographic inversion centre. There is half a BPDS molecule and one β-alanine molecule in the asymmetric unit. The carboxylic group of the β-alanine forms hydrogen bonds with another such group to give a dimeric centrosymmetric R₂²(8) ring (Etter, 1990). Each of the NH₃⁺ groups in the extended β-alanine dimers is hydrogen bonded to three O atoms belonging to three different sulfonate groups, and vice versa for the sulfonate groups, resulting in a puckered two-dimensional sheet, as illustrated in Fig. 2. The hydrogen-bonded ribbons formed by the amino H atoms and the sulfonate O atoms can be described as C₂²(6)R₄⁴(12) (Etter, 1990). A similar 12-membered ring motif formed by N—H···O hydrogen bonds was observed in bis(glycine)1,5-naphthalenedisulfonate dihydrate (Sudbeck et al., 1995).

All the hydrogen-bond donors and acceptors in (I) are involved in strong hydrogen-bonding interactions, as shown in Table 1. Interestingly, the length of the extended β-alanine dimer, 11.34 Å, i.e. the distance between the two terminal N atoms, is compatible with the 10.63 Å length of BPDS. Also, the least-squares plane of the two carboxylic groups is almost co-planar with the biphenyl rings, as indicated by the dihedral angle of 5.9°. Finally, there is one further hydrogen bond formed between a C—H of the phenyl ring and an alanine O atom, with C2···O5 3.359 Å and C2—H1···O5 158.3°. This weak hydrogen bond is formed between two adjacent sheets and extends the two-dimensional array into a three-dimensional framework.

A search of the Cambridge Structural Database (CSD; Release ?; Allen & Kennard, 1993) shows that there are a total of three entries containing free β-alanine. Two of them are zwitterionic β-alanine [BALNIN (Jose & Pant, 1965) and BALNIN01 (Papavinasam et al., 1986)], and one is cationic β-alanine (JAFHON; Averbuch-Pouchot et al., 1988) crystallized as a phosphate salt. Compared with the three reported β-alanines, that in (I) has a different backbone conformation. The torsion angle of the C—C—C—N backbone is 84.0, 83.2, 60.2 and 174.3 (2)° in BALNIN, BALNIN01, JAFHON and (I), respectively. This can be understood as the result of self-tuning during the assembly process, for better intermolecular hydrogen-bonding interactions and a closer packing arrangement.

N—H···O hydrogen bonds formed between the amino H atoms of guanidinium and the sulfonate O atoms of BPDS have been used in organic crystal engineering to construct crystalline materials with inclusion properties (Swift et al., 1998; Russell et al., 1997). During the process of studying the coordination property of sulfonate toward transition metals, we identified a novel hydrogen-bonding pattern, formed by the metal-coordinated amino H atoms and the sulfonate O atoms, acting as the supramolecular synthon which provides the directing forces for the assembly of one-dimensional Cd^II arenedisulfonates (Cai et al., 2001). The title compound provides another interesting example of how N—H···O hydrogen bonds can be utilized to direct the assembly process in crystal engineering with aminosulfonate compounds.

S2. Experimental

4,4'-Biphenyldisulfonic acid (0.15 g, 0.5 mmol) was added to an aqueous solution of β-alanine (0.09 g, 1 mmol). The resulting solution was allowed to stand at room temperature. After 7 d, colourless plates of (I) were collected in 45% yield. Found: C 43.75, H 4.85, N 5.76, S 13.09%; C₁₈H₂₄O₁₀N₂S₂ requires C 43.90, H 4.91, N 5.69, S 13.02%.

S3. Refinement

All H atoms were located from the difference Fourier map. The refined C—H distances are in the range 0.84 (3)–0.99 (2) Å and U_iso values for H atoms attached to C are in the range 0.043 (6)–0.059 (7) Ų.

Computing details

Data collection: SMART (Bruker, 1998); cell refinement: SMART; data reduction: SAINT+ (Bruker,1999); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 1998); software used to prepare material for publication: SHELXTL.

Figures

	Fig. 1. The molecular structure of (I) generated by inversion centres, showing 30% probability displacement ellipsoids. H atoms are drawn as small spheres of arbitrary radii and hydrogen bonds are shown as dashed lines.
	Fig. 2. The extended two-dimensional network formed by the complementary N—H···O hydrogen bonds.

Bis(β-alaninium) 4,4'-biphenyldisulfonate

Crystal data

2C3H8O2N^+·C12H8O6S2^2^−	Z = 1
Mr = 492.51	F(000) = 258
Triclinic, P1	Dx = 1.556 Mg m^−3
a = 5.4565 (5) Å	Mo Kα radiation, λ = 0.71073 Å
b = 7.3922 (7) Å	Cell parameters from 945 reflections
c = 13.4798 (12) Å	θ = 4.3–29.7°
α = 99.197 (2)°	µ = 0.31 mm^−1
β = 90.039 (2)°	T = 293 K
γ = 101.465 (2)°	Plate, colourless
V = 525.72 (8) Å^3	0.27 × 0.15 × 0.05 mm

Data collection

Bruker SMART (query) CCD area-detector diffractometer	2102 independent reflections
Radiation source: fine-focus sealed tube	1906 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.021
ϕ and ω scans	θmax = 26.4°, θmin = 1.5°
Absorption correction: multi-scan (SADABS; Blessing, 1995)	h = −6→6
Tmin = 0.920, Tmax = 0.985	k = −9→8
3197 measured reflections	l = −15→16

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.035	All H-atom parameters refined
wR(F^2) = 0.114	w = 1/[σ^2(Fo^2) + (0.0722P)^2 + 0.1603P] where P = (Fo^2 + 2Fc^2)/3
S = 1.09	(Δ/σ)max < 0.001
2102 reflections	Δρmax = 0.44 e Å^−3
194 parameters	Δρmin = −0.32 e Å^−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 1997), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.056 (8)

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
S1	0.34022 (8)	0.73526 (6)	0.87770 (3)	0.03136 (19)
O1	0.5200 (3)	0.90895 (18)	0.88008 (10)	0.0425 (4)
O2	0.1284 (3)	0.7577 (3)	0.93856 (12)	0.0708 (6)
O3	0.4589 (3)	0.58485 (19)	0.89754 (11)	0.0502 (4)
O4	−0.0809 (3)	0.0222 (2)	0.62283 (10)	0.0480 (4)
O5	0.2932 (3)	0.1153 (2)	0.56096 (11)	0.0497 (4)
N1	0.2312 (3)	0.2104 (2)	0.91989 (12)	0.0351 (4)
C1	0.0455 (3)	0.5358 (2)	0.55299 (12)	0.0260 (4)
C2	0.2886 (3)	0.6392 (3)	0.57528 (13)	0.0340 (4)
C3	0.3752 (3)	0.7031 (3)	0.67359 (13)	0.0328 (4)
C4	0.2204 (3)	0.6669 (2)	0.75212 (12)	0.0267 (3)
C5	−0.0238 (3)	0.5687 (3)	0.73227 (13)	0.0334 (4)
C6	−0.1078 (3)	0.5023 (3)	0.63366 (13)	0.0340 (4)
C7	0.0887 (4)	0.1514 (3)	0.82206 (13)	0.0348 (4)
C8	0.2660 (4)	0.1699 (3)	0.73636 (13)	0.0334 (4)
C9	0.1420 (3)	0.0957 (2)	0.63457 (14)	0.0337 (4)
H6	0.013 (4)	0.035 (3)	0.8193 (17)	0.043 (6)*
H7	0.396 (4)	0.109 (3)	0.7410 (17)	0.044 (6)*
H1	0.405 (5)	0.674 (3)	0.5251 (19)	0.053 (7)*
H2	0.527 (5)	0.758 (4)	0.682 (2)	0.056 (7)*
H8	0.346 (4)	0.302 (3)	0.7339 (17)	0.043 (6)*
H5	−0.033 (4)	0.226 (3)	0.8208 (17)	0.043 (6)*
H3	−0.128 (5)	0.544 (3)	0.781 (2)	0.058 (7)*
H4	−0.272 (5)	0.435 (4)	0.624 (2)	0.059 (7)*
H10	0.311 (5)	0.324 (4)	0.9204 (19)	0.053 (7)*
H11	0.125 (5)	0.207 (4)	0.970 (2)	0.061 (7)*
H12	0.337 (5)	0.135 (4)	0.930 (2)	0.051 (7)*
H9	0.210 (7)	0.066 (5)	0.505 (3)	0.093 (11)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S1	0.0323 (3)	0.0377 (3)	0.0211 (3)	0.00322 (18)	−0.00409 (16)	0.00093 (17)
O1	0.0506 (8)	0.0344 (7)	0.0366 (7)	−0.0008 (6)	−0.0122 (6)	−0.0003 (5)
O2	0.0422 (8)	0.1261 (16)	0.0305 (8)	0.0061 (9)	0.0054 (6)	−0.0140 (9)
O3	0.0652 (10)	0.0391 (8)	0.0447 (8)	0.0030 (7)	−0.0249 (7)	0.0115 (6)
O4	0.0419 (8)	0.0637 (9)	0.0304 (7)	−0.0058 (7)	−0.0009 (6)	0.0041 (6)
O5	0.0487 (8)	0.0643 (10)	0.0270 (7)	−0.0072 (7)	0.0048 (6)	0.0038 (6)
N1	0.0418 (9)	0.0353 (8)	0.0256 (8)	0.0042 (7)	0.0002 (6)	0.0019 (6)
C1	0.0273 (8)	0.0266 (8)	0.0233 (8)	0.0052 (6)	−0.0015 (6)	0.0024 (6)
C2	0.0322 (9)	0.0392 (9)	0.0254 (8)	−0.0022 (7)	0.0029 (7)	0.0014 (7)
C3	0.0278 (9)	0.0363 (9)	0.0288 (9)	−0.0021 (7)	−0.0011 (7)	−0.0001 (7)
C4	0.0290 (8)	0.0280 (8)	0.0229 (8)	0.0070 (6)	−0.0029 (6)	0.0017 (6)
C5	0.0281 (8)	0.0469 (10)	0.0236 (8)	0.0038 (7)	0.0015 (6)	0.0054 (7)
C6	0.0240 (8)	0.0480 (10)	0.0265 (9)	0.0009 (7)	−0.0016 (6)	0.0034 (7)
C7	0.0349 (9)	0.0402 (10)	0.0267 (9)	0.0021 (8)	−0.0016 (7)	0.0046 (7)
C8	0.0355 (9)	0.0350 (9)	0.0272 (9)	0.0028 (7)	0.0000 (7)	0.0025 (7)
C9	0.0408 (10)	0.0304 (8)	0.0276 (9)	0.0020 (7)	0.0000 (7)	0.0041 (6)

Geometric parameters (Å, º)

S1—O2	1.4387 (16)	C7—C8	1.513 (2)
S1—O1	1.4484 (14)	C8—C9	1.501 (2)
S1—O3	1.4522 (15)	N1—H10	0.86 (3)
S1—C4	1.7725 (16)	N1—H11	0.89 (3)
O4—C9	1.228 (2)	N1—H12	0.90 (3)
O5—C9	1.298 (2)	C2—H1	0.96 (3)
N1—C7	1.488 (2)	C3—H2	0.84 (3)
C1—C6	1.396 (2)	C5—H3	0.89 (3)
C1—C2	1.399 (2)	C6—H4	0.93 (3)
C1—C1^i	1.490 (3)	C7—H6	0.87 (2)
C2—C3	1.383 (3)	C7—H5	0.95 (2)
C3—C4	1.381 (2)	C8—H7	0.92 (2)
C4—C5	1.388 (2)	C8—H8	0.99 (2)
C5—C6	1.385 (2)
O2—S1—O1	112.62 (11)	H11—N1—H12	106 (2)
O2—S1—O3	114.05 (12)	H10—N1—C7	106.6 (17)
O1—S1—O3	111.81 (9)	H11—N1—C7	109.4 (18)
O2—S1—C4	105.98 (9)	H12—N1—C7	113.5 (17)
O1—S1—C4	106.48 (8)	H1—C2—C3	115.2 (15)
O3—S1—C4	105.13 (8)	H1—C2—C1	123.5 (15)
C6—C1—C2	117.48 (15)	H2—C3—C4	123.7 (18)
C6—C1—C1^i	121.44 (18)	H2—C3—C2	116.1 (18)
C2—C1—C1^i	121.08 (18)	H3—C5—C6	118.5 (17)
C3—C2—C1	121.25 (16)	H3—C5—C4	121.9 (17)
C4—C3—C2	120.14 (16)	H4—C6—C5	116.9 (16)
C3—C4—C5	119.90 (15)	H4—C6—C1	121.5 (16)
C3—C4—S1	119.67 (13)	H6—C7—H5	109 (2)
C5—C4—S1	120.34 (13)	H6—C7—N1	107.6 (16)
C6—C5—C4	119.59 (16)	H5—C7—N1	108.3 (14)
C5—C6—C1	121.59 (16)	H6—C7—C8	110.1 (15)
N1—C7—C8	109.88 (15)	H5—C7—C8	112.0 (14)
C9—C8—C7	113.60 (15)	H7—C8—H8	105.6 (19)
O4—C9—O5	123.66 (17)	H7—C8—C9	106.5 (14)
O4—C9—C8	122.77 (16)	H8—C8—C9	105.3 (13)
O5—C9—C8	113.57 (16)	H7—C8—C7	112.6 (14)
H10—N1—H11	110 (2)	H8—C8—C7	112.5 (13)
H10—N1—H12	111 (2)
C6—C1—C2—C3	1.1 (3)	O3—S1—C4—C5	92.72 (16)
C1^i—C1—C2—C3	−178.86 (19)	C3—C4—C5—C6	2.2 (3)
C1—C2—C3—C4	−0.6 (3)	S1—C4—C5—C6	−174.47 (14)
C2—C3—C4—C5	−1.1 (3)	C4—C5—C6—C1	−1.7 (3)
C2—C3—C4—S1	175.61 (14)	C2—C1—C6—C5	0.1 (3)
O2—S1—C4—C3	154.96 (16)	C1^i—C1—C6—C5	−179.99 (19)
O1—S1—C4—C3	34.84 (16)	N1—C7—C8—C9	174.32 (15)
O3—S1—C4—C3	−83.93 (16)	C7—C8—C9—O4	−2.0 (3)
O2—S1—C4—C5	−28.39 (18)	C7—C8—C9—O5	178.61 (17)
O1—S1—C4—C5	−148.51 (15)

Symmetry code: (i) −x, −y+1, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H10···O3	0.86 (3)	2.01 (3)	2.863 (2)	169 (2)
N1—H11···O2^ii	0.89 (3)	1.89 (3)	2.756 (2)	166 (2)
N1—H12···O1^iii	0.90 (3)	2.13 (3)	2.958 (2)	151 (2)
O5—H9···O4^iv	0.87 (4)	1.83 (4)	2.690 (2)	171 (3)

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