The anilinium chloride adduct of 4-bromo-N-phenylbenzene­sulfonamide

The title compound anilinium chloride–4-bromo-N-phenyl­benzene­sulfonamide (1/1), C₆H₈N⁺·Cl⁻·C₁₂H₁₀BrNO₂S, displays a hydrogen-bonded ladder motif with four independent N—H...Cl bonds in which both the NH group of the sulfonamide molecule and the NH₃ group of the anilinium ion [N...Cl = 3.135 (3)–3.196 (2) Å and N—H...Cl = 151–167°] are involved. This hydrogen-bonded chain contains two independent R₄²(8) rings and each chloride ion acts as an acceptor of four hydrogen bonds.

S1. Comment

In a project to relate crystal structure to molecular structure, which we term structural systematics, large numbers of related molecules are synthesized and their crystal structures determined. For this purpose, it is essential to choose compounds that can be synthesized readily, and for well known reactions it is usually easy to determine whether this is the case. By contrast, it is not possible to forecast whether the products will crystallize easily in sufficient size and quality for single-crystal diffraction, except in a very general and imperfect way by experience of crystallizing large numbers of related compounds. In this project, over 100 benzene sulfonamides of the general structure (I) have been synthesized, where X and Y are H, CH₃, F, Cl, Br, I, CF₃, CN, NO₂ and MeO, and, additionally, Y is ethynyl. These sulfonamides generally crystallize more readily than the related carboxamides, chalcones, or pyridine and other heterocyclic analogues, the structural systematics of which are also under investigation. The syntheses are usually trivial. In a few cases, the not unexpected disulfonyl by-product has been isolated. Adjustment of the reactant quantities and reaction conditions has allowed the required product to be formed exclusively.

In only one case out of more than 100 samples of this set, and out of many hundred examples in the extended set, has an unexpected product been encountered. This was during the synthesis intended to produce the compound (II), where X = Br and Y = H. This compound is difficult to crystallize because of its extreme solubility in most solvents, including hydrocarbons, and the result of evaporative crystallization is generally a viscous syrup. During an attempted crystallization of (II) from toluene, novel crystals were encountered which were initially thought to be the toluene solvate of the hydrochloride of (II). This seemed chemically improbable, because of the weak basicity of sulfonamides, although it is possible for favourable crystal structures of salts and adducts to contradict expectations derived from solution-determined basicities. Refinement of the structure led to the understanding of the composition as the anilinium chloride adduct (III) of the required sulfonamide (II).

The bond lengths and angles of the sulfonamide molecule (Fig. 1) are in accordance with those in previously reported molecules of the general structure (I) [X = Cl and Y = Br, and X = Br and Y = H (Rérat, 1969); X = Y = MeO (Pokrywiecki et al., 1973); X = I and Y = NO₂, and X = NO₂ and Y = I (Kelly et al., 2002)]. Our own systematic investigation of crystal structures formed by molecules (I) has shown that they are generally dominated by intermolecular N—H···O hydrogen-bond interactions between the amine group and one sulfonyl O atom, with the exception of only a few cases where X or Y is CN or NO₂. These interactions generate two distinct supramolecular synthons, viz. a dimer resulting in the formation of R²₂(8) rings (Bernstein et al., 1995) and a chain motif. These typical N—H···O chains also occur in the single-component structure of the sulfonamide (II), to be published elswhere. However, the formation of either of the two N—H···O bond motifs is prevented in the cocrystal (III) by the presence of the chloride ion. Instead, sulfonamide molecules are linked by N—H···Cl hydrogen bonds to chloride ions. Furthermore, Cl⁻ is at the same time involved in another three N—H···Cl bonding interactions with the ammonium groups of three different anilinium ions. In turn, each anilinium ion is connected via its ammonium group to three Cl⁻ ions (Fig. 2). As a result, two crystallographically independent hydrogen bonded rings are formed, which are both of the R²₄(8) type. Each ring has a centre of inversion, and adjacent rings, which are crystallographically independent, ···Cl1···H2—N2—H4···Cl1··· and ···Cl1···H3—N2—H4···Cl1···, have a common N2—H4···Cl1 edge. Thus, the structure of a corrugated ladder is obtained. This one-dimensional infinite structure propagates parallel to [100]. It consists of two antiparallel strands of three-connected nodes, composed alternately by chloride ions and amine groups of the anilinium ions. Additionally, each chloride node has a fourth connection to one sulfonamide molecule, and neighbouring sulfonamide molecules attached to the same strand of the ladder are related by translation symmetry. By contrast, two molecules connected to chloride nodes located in different strands of the same ladder are related by inversion symmetry.

For the three H atoms in the ammonium group of the anilinium ion, the structure of (III) contains one chloride ion as a potential hydrogen-bond acceptor, and ignoring the sulfonamide molecule, a net consisting of three-connected chloride and ammonium nodes is formed as result. The same situation can be found in the structure of anilinium chloride (López-Duplá et al., 2003), from which, however, a fundamentally different topology arises. Here, a two-dimensional hydrogen-bonded net with (6,3) topology (Wells, 1977) is formed in which the two types of nodes alternate. By contrast, the ladder motif observed in (III) occurs in other related bromide and iodide structures, such as 2-methyl-4-nitroanilinium iodide (Lemmerer & Billing, 2006), while the high-and low-temperature forms of anilinium bromide (Sakai & Terauchi, 1981; Fecher et al., 1981) and anilinium iodide (Fecher & Weiss, 1986) produce a disordered derivative of the same ladder.

Each N—H···Cl bonded ladder exhibits additional internal close C14—H14···O1 contacts between anilinium ions and molecules of (II) (Table 1). There is also a set of two close Br···π contacts between two molecules of (II) which belong to neighbouring ladders related by translation along the c axis. The separation between Br and the centroid of the benzene ring is 3.52 Å. Furthermore, the anilinium ions of two neighbouring ladders related by translation along the b axis are π–π stacked (centroid separation 4.01 Å). The same two units are also linked by two sets of C—H···Cl contacts between their anilinium and chloride ions (Table 1). All described close contacts are shown in the packing diagram of Fig. 3.

The origin of the anilinium chloride as the result of part of the reactant aniline acting as a proton acceptor is readily understood. It is surprising that it was not eliminated during the normal work-up procedure of evaporation to small volume to remove the pyridine and pyridine hydrochloride, followed by puddling with water to effect solidification. If this persistence into the final product is due to the particular stability of the crystal structure, then it is surprising that analogous compounds have not been frequently encountered during this project.

S2. Experimental

4-Bromobenzenesulfonyl chloride (0.255 g, 1 mmol) was added to a solution of aniline (0.093 g, 1 mmol) in pyridine (3 ml). The orange–red colour that formed was discharged on boiling. After boiling for 30 min, the solution was evaporated to small bulk under nitrogen until white fumes of pyridine hydrochloride began to appear. The cooled residue was treated with water and scratched with a rod until it solidified. The product was filtered off, dissolved in ethanol (5 ml) and allowed to evaporate to a syrup. The product was taken up in toluene (4 ml) and allowed to evaporate until crystals appeared. The larger rods were identified as the anilinium chloride adduct of N-phenyl-4-bromobenzenesulfonamide, and the smaller plates as N-phenyl-4-bromobenzenesulfonamide.

S3. Refinement

All H atoms were located in difference maps. The position of the H atom attached to N1 was refined with the N—H distance restrained to 0.900 (15) Å. All other H atoms were treated as riding, with C—H distances of 0.95 Å and N—H distances of 0.91 Å. All U_iso(H) values were refined freely.

Computing details

Data collection: COLLECT (Hooft, 1998); cell refinement: DENZO (Otwinowski & Minor, 1997) and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP (Bruker, 1998) and Mercury (Macrae et al., 2006); software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. : The asymmetric unit of (III), showing the atomic numbering scheme. Displacement ellipsoids are drawn at the 30% level.
	Fig. 2. : One-dimensional hydrogen-bonded net (ladder) between sulfonamide molecules, anilinium ions and chloride ions in (III). Hydrogen bonds are marked with dashed lines. Atoms marked with an asterisk (*) or hash (#) are at the symmetry positions (x − 1, y, z) and (-x + 1, −y, −z + 1), respectively.
	Fig. 3. : Part of the crystal structure of (III), consisting of two complete N—H···Cl bonded ladders (lower section) and portions of another two such units, showing the interplay between different types of intermolecular interaction. The structure is viewed in the direction of the translation vector of the N—H···Cl hydrogen-bonded chains. Only H atoms involved in a contact listed in Table 1 are shown.

Anilinium chloride–N-phenyl-4-bromobenzenesulfonamide (1/1)

Crystal data

C6H8N^+·Cl^−·C12H10BrNO2S	Z = 2
Mr = 441.76	F(000) = 448
Triclinic, P1	Dx = 1.555 Mg m^−3
a = 5.6705 (4) Å	Mo Kα radiation, λ = 0.71073 Å
b = 9.9954 (7) Å	Cell parameters from 3083 reflections
c = 17.3234 (12) Å	θ = 1.0–26.0°
α = 83.137 (4)°	µ = 2.45 mm^−1
β = 81.655 (4)°	T = 120 K
γ = 77.163 (3)°	Prism, colourless
V = 943.31 (11) Å^3	0.50 × 0.20 × 0.20 mm

Data collection

Bruker–Nonius KappaCCD diffractometer	3286 independent reflections
Radiation source: Bruker-Nonius FR591 rotating anode	2646 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.039
Detector resolution: 9.091 pixels mm^-1	θmax = 25.1°, θmin = 3.3°
ϕ and ω scans	h = −6→6
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	k = −11→11
Tmin = 0.359, Tmax = 0.615	l = −20→20
8226 measured reflections

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)] = 0.034	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.088	w = 1/[σ^2(Fo^2) + (0.045P)^2 + 0.0802P] where P = (Fo^2 + 2Fc^2)/3
S = 1.04	(Δ/σ)max = 0.001
3286 reflections	Δρmax = 0.37 e Å^−3
248 parameters	Δρmin = −0.55 e Å^−3
2 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0060 (13)

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	1.07484 (6)	−0.26420 (3)	−0.008944 (19)	0.04259 (15)
S1	0.39401 (13)	0.02539 (7)	0.27817 (4)	0.02599 (19)
O1	0.4416 (4)	−0.0549 (2)	0.35095 (11)	0.0334 (5)
O2	0.1515 (4)	0.0633 (2)	0.25729 (12)	0.0314 (5)
N1	0.4972 (5)	0.1629 (2)	0.28214 (13)	0.0261 (5)
H1	0.610 (4)	0.149 (3)	0.3144 (14)	0.028 (8)*
C1	0.5774 (5)	−0.0621 (3)	0.20042 (16)	0.0250 (6)
C2	0.4852 (6)	−0.0578 (3)	0.12992 (17)	0.0292 (7)
H2A	0.3230	−0.0108	0.1239	0.037 (9)*
C3	0.6324 (6)	−0.1227 (3)	0.06868 (18)	0.0314 (7)
H3A	0.5708	−0.1228	0.0206	0.042 (9)*
C4	0.8693 (5)	−0.1871 (3)	0.07796 (17)	0.0290 (7)
C5	0.9591 (6)	−0.1950 (3)	0.14920 (18)	0.0338 (7)
H5	1.1206	−0.2431	0.1554	0.047 (10)*
C6	0.8114 (6)	−0.1324 (3)	0.21064 (18)	0.0320 (7)
H6	0.8700	−0.1375	0.2598	0.049 (10)*
C7	0.5082 (5)	0.2736 (3)	0.22341 (16)	0.0231 (6)
C8	0.3512 (5)	0.3086 (3)	0.16661 (17)	0.0272 (6)
H8	0.2354	0.2544	0.1636	0.033 (8)*
C9	0.3650 (6)	0.4240 (3)	0.11402 (17)	0.0306 (7)
H9	0.2582	0.4483	0.0748	0.024 (7)*
C10	0.5334 (6)	0.5041 (3)	0.11825 (18)	0.0316 (7)
H10	0.5413	0.5829	0.0822	0.040 (9)*
C11	0.6885 (6)	0.4683 (3)	0.17500 (18)	0.0326 (7)
H11	0.8027	0.5233	0.1784	0.044 (9)*
C12	0.6793 (5)	0.3522 (3)	0.22734 (17)	0.0258 (6)
H12	0.7894	0.3267	0.2656	0.024 (8)*
C13	0.1287 (5)	0.2780 (3)	0.55967 (15)	0.0213 (6)
C14	−0.0960 (5)	0.2865 (3)	0.60540 (17)	0.0302 (7)
H14	−0.1875	0.2172	0.6065	0.042 (9)*
C15	−0.1834 (6)	0.3980 (3)	0.64914 (18)	0.0370 (7)
H15	−0.3357	0.4051	0.6812	0.052 (10)*
C16	−0.0513 (6)	0.4987 (3)	0.64662 (19)	0.0386 (8)
H16	−0.1130	0.5752	0.6767	0.042 (9)*
C17	0.1702 (6)	0.4888 (3)	0.60061 (19)	0.0340 (7)
H17	0.2601	0.5590	0.5989	0.041 (9)*
C18	0.2628 (5)	0.3779 (3)	0.55700 (17)	0.0268 (6)
H18	0.4164	0.3707	0.5257	0.044 (9)*
N2	0.2194 (4)	0.1614 (2)	0.51242 (14)	0.0252 (5)
H2	0.3644	0.1702	0.4842	0.030 (8)*
H3	0.1098	0.1597	0.4792	0.035 (9)*
H4	0.2405	0.0817	0.5444	0.052 (11)*
Cl1	0.76523 (12)	0.15174 (6)	0.43098 (4)	0.02355 (18)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br1	0.0436 (2)	0.0446 (2)	0.0336 (2)	0.00656 (15)	−0.00403 (15)	−0.01058 (15)
S1	0.0296 (4)	0.0287 (4)	0.0218 (4)	−0.0114 (3)	−0.0029 (3)	−0.0010 (3)
O1	0.0450 (13)	0.0355 (11)	0.0223 (11)	−0.0181 (10)	−0.0050 (10)	0.0067 (9)
O2	0.0271 (11)	0.0401 (11)	0.0290 (11)	−0.0117 (9)	−0.0009 (9)	−0.0055 (9)
N1	0.0338 (15)	0.0285 (12)	0.0197 (13)	−0.0111 (11)	−0.0098 (11)	−0.0003 (10)
C1	0.0311 (17)	0.0204 (13)	0.0251 (15)	−0.0095 (12)	−0.0054 (13)	0.0012 (11)
C2	0.0298 (17)	0.0287 (14)	0.0293 (16)	−0.0022 (13)	−0.0131 (13)	0.0004 (12)
C3	0.0403 (19)	0.0267 (15)	0.0273 (16)	−0.0005 (13)	−0.0135 (14)	−0.0037 (13)
C4	0.0347 (17)	0.0225 (14)	0.0286 (16)	−0.0029 (12)	−0.0050 (14)	−0.0025 (12)
C5	0.0285 (17)	0.0349 (16)	0.0379 (18)	−0.0026 (13)	−0.0092 (14)	−0.0039 (14)
C6	0.0333 (17)	0.0374 (16)	0.0290 (16)	−0.0095 (14)	−0.0114 (14)	−0.0049 (13)
C7	0.0254 (15)	0.0210 (13)	0.0206 (14)	−0.0010 (11)	0.0000 (12)	−0.0037 (11)
C8	0.0261 (16)	0.0300 (15)	0.0264 (15)	−0.0063 (12)	−0.0053 (13)	−0.0034 (12)
C9	0.0312 (17)	0.0324 (15)	0.0257 (16)	−0.0021 (13)	−0.0060 (14)	0.0018 (13)
C10	0.0329 (17)	0.0265 (15)	0.0300 (17)	−0.0005 (13)	0.0008 (14)	0.0023 (13)
C11	0.0324 (17)	0.0256 (15)	0.0404 (18)	−0.0079 (13)	−0.0019 (15)	−0.0047 (13)
C12	0.0234 (15)	0.0278 (14)	0.0266 (15)	−0.0049 (12)	−0.0027 (13)	−0.0048 (12)
C13	0.0223 (15)	0.0194 (13)	0.0213 (14)	−0.0004 (11)	−0.0085 (12)	0.0007 (11)
C14	0.0260 (16)	0.0380 (16)	0.0289 (16)	−0.0114 (13)	−0.0058 (13)	−0.0007 (13)
C15	0.0279 (17)	0.0519 (19)	0.0296 (17)	−0.0021 (15)	−0.0034 (14)	−0.0089 (15)
C16	0.0354 (19)	0.0428 (18)	0.0363 (18)	0.0045 (15)	−0.0089 (15)	−0.0174 (15)
C17	0.0359 (18)	0.0261 (15)	0.0423 (19)	−0.0072 (13)	−0.0053 (15)	−0.0100 (14)
C18	0.0268 (16)	0.0262 (14)	0.0289 (16)	−0.0079 (12)	−0.0034 (13)	−0.0041 (12)
N2	0.0231 (13)	0.0218 (12)	0.0319 (13)	−0.0059 (10)	−0.0058 (11)	−0.0023 (10)
Cl1	0.0250 (4)	0.0241 (3)	0.0231 (4)	−0.0063 (3)	−0.0049 (3)	−0.0036 (3)

Geometric parameters (Å, º)

Br1—C4	1.894 (3)	C9—H9	0.9500
S1—O2	1.430 (2)	C10—C11	1.377 (4)
S1—O1	1.438 (2)	C10—H10	0.9500
S1—N1	1.621 (2)	C11—C12	1.390 (4)
S1—C1	1.769 (3)	C11—H11	0.9500
N1—C7	1.417 (3)	C12—H12	0.9500
N1—H1	0.878 (14)	C13—C18	1.377 (4)
C1—C6	1.382 (4)	C13—C14	1.390 (4)
C1—C2	1.389 (4)	C13—N2	1.460 (3)
C2—C3	1.382 (4)	C14—C15	1.381 (4)
C2—H2A	0.9500	C14—H14	0.9500
C3—C4	1.378 (4)	C15—C16	1.375 (4)
C3—H3A	0.9500	C15—H15	0.9500
C4—C5	1.389 (4)	C16—C17	1.377 (4)
C5—C6	1.376 (4)	C16—H16	0.9500
C5—H5	0.9500	C17—C18	1.378 (4)
C6—H6	0.9500	C17—H17	0.9500
C7—C8	1.384 (4)	C18—H18	0.9500
C7—C12	1.391 (4)	N2—H2	0.9100
C8—C9	1.391 (4)	N2—H3	0.9100
C8—H8	0.9500	N2—H4	0.9100
C9—C10	1.390 (4)
O2—S1—O1	120.29 (12)	C8—C9—H9	119.6
O2—S1—N1	109.66 (13)	C11—C10—C9	119.5 (3)
O1—S1—N1	104.16 (12)	C11—C10—H10	120.2
O2—S1—C1	106.73 (13)	C9—C10—H10	120.2
O1—S1—C1	108.79 (13)	C10—C11—C12	120.5 (3)
N1—S1—C1	106.49 (12)	C10—C11—H11	119.8
C7—N1—S1	127.8 (2)	C12—C11—H11	119.8
C7—N1—H1	114.6 (19)	C11—C12—C7	119.7 (3)
S1—N1—H1	112.3 (19)	C11—C12—H12	120.2
C6—C1—C2	121.1 (3)	C7—C12—H12	120.2
C6—C1—S1	119.3 (2)	C18—C13—C14	121.4 (2)
C2—C1—S1	119.6 (2)	C18—C13—N2	119.9 (2)
C3—C2—C1	119.2 (3)	C14—C13—N2	118.6 (2)
C3—C2—H2A	120.4	C15—C14—C13	118.6 (3)
C1—C2—H2A	120.4	C15—C14—H14	120.7
C4—C3—C2	119.5 (3)	C13—C14—H14	120.7
C4—C3—H3A	120.3	C16—C15—C14	120.5 (3)
C2—C3—H3A	120.3	C16—C15—H15	119.8
C3—C4—C5	121.3 (3)	C14—C15—H15	119.8
C3—C4—Br1	118.8 (2)	C15—C16—C17	120.1 (3)
C5—C4—Br1	119.9 (2)	C15—C16—H16	119.9
C6—C5—C4	119.2 (3)	C17—C16—H16	119.9
C6—C5—H5	120.4	C16—C17—C18	120.6 (3)
C4—C5—H5	120.4	C16—C17—H17	119.7
C5—C6—C1	119.6 (3)	C18—C17—H17	119.7
C5—C6—H6	120.2	C13—C18—C17	118.8 (3)
C1—C6—H6	120.2	C13—C18—H18	120.6
C8—C7—C12	120.4 (2)	C17—C18—H18	120.6
C8—C7—N1	123.0 (2)	C13—N2—H2	109.5
C12—C7—N1	116.6 (3)	C13—N2—H3	109.5
C7—C8—C9	119.2 (3)	H2—N2—H3	109.5
C7—C8—H8	120.4	C13—N2—H4	109.5
C9—C8—H8	120.4	H2—N2—H4	109.5
C10—C9—C8	120.7 (3)	H3—N2—H4	109.5
C10—C9—H9	119.6

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···Cl1	0.88 (1)	2.33 (2)	3.157 (3)	157 (3)
N2—H2···Cl1	0.91	2.30	3.196 (2)	167
N2—H3···Cl1^i	0.91	2.25	3.135 (3)	163
N2—H4···Cl1^ii	0.91	2.33	3.152 (2)	151
C14—H14···O1^iii	0.95	2.39	3.307 (3)	163
C17—H17···Cl1^iv	0.95	2.85	3.661 (3)	144

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