Hydrogen-bonded molecular ladders in 1,4-bis(4-chlorophenylsulfonyl)-2,5-dimethylbenzene

In the title compound, C₂₀H₁₆Cl₂O₄S₂, the mol­ecules lie across centres of inversion. A single type of intermolecular C—H...O hydrogen bond, with a C...O distance of 3.254 (3) Å and a C—H...O angle of 132°, links the mol­ecules into ladders whose uprights form C(6) chains and whose rungs enclose centrosymmetric R(22) rings.

S1. Comment

In molecular solids which contain an excess of hard hydrogen-bond acceptors over hard hydrogen-bond donors (Braga et al., 1995), it is to be expected that C—H bonds, particularly those in aromatic systems, will participate as donors in hydrogen bonds of the types C—H···O or C—H···N (Hanton et al., 1992). Aromatic sulfones are particularly effective in C—H···O hydrogen-bond formation between aromatic C—H bonds acting as hydrogen-bond donors and sulfone S=O bonds acting as acceptors (Glidewell et al., 1995; Meehan et al., 1997; Ferguson et al., 1999). In particular, the bis(sulfones) (PhSO₂)₂CH₂ (Glidewell et al., 1995) and (4-MeOC₆H₄SO₂)₂CH₂ (Meehan et al., 1997) form one-dimensional chains and a three-dimensional framework, respectively, as a result of such hydrogen-bond formation. As an example of a bis(sulfone) in which a further aromatic nucleus has been incorporated between the two sulfone groups, we now report the structure of the title compound, (I), wherein the molecules are linked into a molecular ladder by C—H···O hydrogen bonds. \sch

Compound (I) crystallizes in the space group P1 with Z = 1; hence the molecules lie across centres of inversion and, for the sake of convenience, the reference molecule has been placed across the inversion centre at (1/2, 1/2, 1/2). The molecular conformation of (I) (Fig. 1) is dominated by the near coplanarity of the O—S—C—C fragments (Table 1). As commonly observed in diaryl sulfones (Ferguson et al., 1999), there is an electrostatic attraction between the S=O bond, which is polarized in the sense S⁺—O⁻, and an ortho C—H bond in the adjacent ring, polarized in the sense C⁻—H⁺. In the most common arrangement, as also found here, each O atom of the sulfone unit interacts with a different ring, so that the local symmetry around the S atom is close to C₂.

Both of the S1—C7—C9ⁱ and C7ⁱ—C9—C91 bond angles [symmetry code: (i) 1 − x, 1 − y, 1 − z] are significantly greater than 120° (Table 1). This type of angular distortion has been observed in several diaryl sulfones where there is a methyl group adjacent to the SO₂ unit (Jeyakanthan et al., 1998), and it may plausibly be interpreted as arising from repulsive interactions between the methyl group and the adjacent sulfone unit. The O—S—O bond angle is much larger than tetrahedral. All the bond lengths are typical of their types (Allen et al., 1987).

There is a single type of intermolecular hydrogen bond (Table 2) linking the molecules. Atom C2 at (x, y, z), a component of the molecule centred at (1/2, 1/2, 1/2), acts as hydrogen-bond donor to O2 at (x, −1 + y, z), which is a component of the molecule centred at (1/2, −1/2, 1/2): repetition of this hydrogen bond generates a C(6) chain running parallel to [010] and generated by translation (Fig. 2). The symmetry-related C2 in the original (1/2, 1/2, 1/2) molecule is at (1 − x, 1 − y, 1 − z), and this acts as donor to O2 at (1 − x, 2 − y, 1 − z), which is a component of the molecule centred at (1/2, 3/2, 1/2); hence another C(6) chain is generated, running antiparallel to the first. The overall supramolecular structure (Fig. 2) thus takes the form of a molecular ladder, in which the uprights are formed by a pair of antiparallel C(6) chains, while the rungs are provided by the central aryl rings of successive molecules. Between the rungs are R₂²(22) rings centred at (1/2, n, 1/2) (n = zero or integer), but the aromatic and methyl H atoms preclude the presence of any void space. A single ladder runs through each unit cell, and there are no significant interactions between neighbouring ladders; in particular, there are no aromatic π···π stacking interactions.

It is notable that the intermolecular hydrogen bonding does not involve the central aryl ring. By contrast, in each of (PhSO₂)₂CH₂ (Glidewell et al., 1995) and (4-MeOC₆H₄SO₂)₂CH₂ (Meehan et al., 1997), both of the C—H bonds of the central methylene unit are engaged in hydrogen-bond formation. It is thus of interest to consider some related compounds retrieved from the Cambridge Structural Database (CSD; Allen & Kennard, 1993). In (PhSO₂CH₂)₂ (FAHNOR; Hauback & Mo, 1990), although the molecules could lie across centres of inversion, as in (I), they do not in fact do so: the molecules are again linked into molecular ladders, but the C—H···O hydrogen bonds forming the uprights use only H atoms from the central –CH₂—CH₂– unit. The ladders are linked into a two-dimensional array by further C—H···O hydrogen bonds involving the aromatic rings. For neither the Z isomer of PhSO₂CH═CHSO₂Ph (DEBYIS; De Lucchi et al., 1985) nor the centrosymmetric E isomer (DEBYOY; De Lucchi et al., 1985) are there any H atom coordinates in the CSD; nonetheless, it is clear from the short intermolecular C···O distances that the intermolecular aggregation is dominated by the aromatic C—H bonds rather than those in the alkene fragment. The factors which determine the involvement of aromatic versus other C—H bonds in these systems are as yet not fully clear. However, it may be expected that aliphatic C—H bonds adjacent to SO₂ units are more acidic than is typical for aliphatic C—H bonds, and thus more like aromatic C—H bonds in their hydrogen-bonding behaviour.

S2. Experimental

A sample of 2,5-bis(4-chlorophenylthio)-1,4-dimethylbenzene (Grant et al., 1987) was oxidized using sodium periodate in CH₂Cl₂ to yield (I). Crystals suitable for single-crystal X-ray diffraction were grown from ethanol solution (m.p. 506–508 K).

S3. Refinement

Compound (I) crystallized in the triclinic system; space group P1 was assumed and confirmed by the analysis. H atoms were treated as riding, with C—H 0.95 (aromatic) and 0.98 Å (methyl). Examination of the structure with PLATON (Spek, 1999) showed that there were no solvent accessible voids in the crystal lattice.

Computing details

Data collection: KappaCCD Server Software (Nonius, 1997); cell refinement: DENZO (Otwinowski & Minor, 1997); data reduction: DENZO; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 1999); software used to prepare material for publication: SHELXL97 and PRPKAPPA (Ferguson, 1999).

Figures

	Fig. 1. The molecule of (I) showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level and H atoms are shown as small spheres of arbitrary radii [symmetry code: (i) 1 − x, 1 − y, 1 − z].
	Fig. 2. Part of the crystal structure of (I) showing formation of a molecular ladder. For the sake of clarity the atom labels are applied to the unit at (x, −1 + y, z) and H atoms not involved in the supramolecular structure are omitted.

1,4-bis(4-chlorophenylsulfonyl)-2,5-dimethylbenzene

Crystal data

C20H16Cl2O4S2	Z = 1
Mr = 455.35	F(000) = 234
Triclinic, P1	Dx = 1.605 Mg m^−3
a = 5.4859 (2) Å	Mo Kα radiation, λ = 0.71073 Å
b = 6.9595 (4) Å	Cell parameters from 2112 reflections
c = 12.5211 (7) Å	θ = 1.7–27.5°
α = 98.6245 (17)°	µ = 0.59 mm^−1
β = 93.561 (4)°	T = 150 K
γ = 92.174 (3)°	Plate, colourless
V = 471.18 (4) Å^3	0.10 × 0.10 × 0.03 mm

Data collection

KappaCCD diffractometer	2112 independent reflections
Radiation source: fine-focus sealed X-ray tube	1689 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.039
ϕ scans and ω scans with κ offsets	θmax = 27.5°, θmin = 1.7°
Absorption correction: multi-scan (SORTAV; Blessing, 1995, 1997)	h = −7→7
Tmin = 0.943, Tmax = 0.985	k = −9→8
5965 measured reflections	l = −16→16

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.039	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.104	H-atom parameters constrained
S = 1.07	Calculated w = 1/[σ^2(Fo^2) + (0.0411P)^2 + 0.1338P] where P = (Fo^2 + 2Fc^2)/3
2112 reflections	(Δ/σ)max < 0.001
128 parameters	Δρmax = 0.39 e Å^−3
0 restraints	Δρmin = −0.53 e Å^−3

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

	x	y	z	Uiso*/Ueq
S1	0.85567 (9)	0.33050 (7)	0.32509 (4)	0.01934 (17)
Cl1	0.20835 (10)	−0.31579 (8)	0.02434 (5)	0.03541 (19)
O1	1.0591 (2)	0.2411 (2)	0.37152 (12)	0.0244 (3)
O2	0.9031 (3)	0.4838 (2)	0.26234 (12)	0.0252 (3)
C1	0.3882 (4)	−0.1363 (3)	0.10821 (16)	0.0227 (5)
C2	0.6042 (4)	−0.1866 (3)	0.15770 (16)	0.0235 (5)
H2	0.6548	−0.3166	0.1451	0.028*
C3	0.7455 (4)	−0.0436 (3)	0.22619 (17)	0.0218 (4)
H3	0.8928	−0.0755	0.2621	0.026*
C4	0.6701 (4)	0.1460 (3)	0.24174 (16)	0.0185 (4)
C5	0.4549 (4)	0.1954 (3)	0.19024 (17)	0.0225 (5)
H5	0.4062	0.3261	0.2012	0.027*
C6	0.3121 (4)	0.0531 (3)	0.12291 (17)	0.0246 (5)
H6	0.1642	0.0845	0.0873	0.030*
C7	0.6607 (3)	0.4218 (3)	0.42770 (16)	0.0177 (4)
C8	0.5380 (3)	0.5875 (3)	0.41112 (16)	0.0194 (4)
H8	0.5674	0.6454	0.3488	0.023*
C9	0.3745 (3)	0.6708 (3)	0.48236 (16)	0.0182 (4)
C91	0.2438 (4)	0.8469 (3)	0.45704 (18)	0.0244 (5)
H91A	0.0696	0.8119	0.4399	0.037*
H91B	0.3134	0.8934	0.3948	0.037*
H91C	0.2635	0.9499	0.5200	0.037*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S1	0.0173 (3)	0.0193 (3)	0.0204 (3)	0.00115 (19)	0.0020 (2)	−0.0005 (2)
Cl1	0.0337 (3)	0.0341 (3)	0.0332 (4)	−0.0099 (2)	−0.0024 (3)	−0.0071 (2)
O1	0.0165 (7)	0.0274 (8)	0.0276 (8)	0.0048 (6)	−0.0008 (6)	−0.0008 (6)
O2	0.0258 (8)	0.0235 (7)	0.0270 (8)	−0.0001 (6)	0.0069 (7)	0.0044 (6)
C1	0.0248 (11)	0.0245 (11)	0.0168 (10)	−0.0068 (9)	0.0028 (9)	−0.0021 (8)
C2	0.0301 (12)	0.0198 (10)	0.0205 (11)	0.0023 (8)	0.0043 (9)	0.0013 (8)
C3	0.0222 (11)	0.0226 (10)	0.0207 (11)	0.0031 (8)	0.0012 (9)	0.0031 (8)
C4	0.0189 (10)	0.0202 (10)	0.0156 (10)	−0.0001 (8)	0.0026 (8)	0.0003 (8)
C5	0.0215 (11)	0.0224 (10)	0.0235 (11)	0.0043 (8)	0.0023 (9)	0.0019 (8)
C6	0.0192 (11)	0.0309 (11)	0.0233 (11)	0.0017 (8)	0.0016 (9)	0.0021 (9)
C7	0.0156 (10)	0.0176 (9)	0.0187 (10)	0.0007 (7)	−0.0008 (8)	−0.0007 (8)
C8	0.0201 (10)	0.0191 (10)	0.0189 (10)	0.0000 (8)	−0.0009 (8)	0.0035 (8)
C9	0.0163 (10)	0.0163 (9)	0.0206 (10)	0.0006 (7)	−0.0019 (8)	−0.0007 (8)
C91	0.0245 (11)	0.0217 (10)	0.0284 (12)	0.0074 (8)	0.0011 (9)	0.0066 (9)

Geometric parameters (Å, º)

S1—O1	1.4322 (14)	C5—H5	0.9500
S1—O2	1.4416 (14)	C6—H6	0.9500
S1—C4	1.772 (2)	C7—C8	1.392 (3)
S1—C7	1.782 (2)	C7—C9^i	1.399 (3)
Cl1—C1	1.738 (2)	C8—C9	1.386 (3)
C1—C2	1.384 (3)	C8—H8	0.9500
C1—C6	1.387 (3)	C9—C7^i	1.399 (3)
C2—C3	1.389 (3)	C9—C91	1.507 (3)
C2—H2	0.9500	C91—H91A	0.9800
C3—C4	1.388 (3)	C91—H91B	0.9800
C4—C5	1.389 (3)	C91—H91C	0.9800
C5—C6	1.384 (3)
O1—S1—O2	118.67 (9)	C4—C5—H5	120.2
O1—S1—C4	108.12 (9)	C5—C6—C1	118.95 (19)
O2—S1—C4	107.72 (9)	C5—C6—H6	120.5
O1—S1—C7	110.17 (9)	C1—C6—H6	120.5
O2—S1—C7	107.60 (9)	C8—C7—C9^i	121.76 (18)
C4—S1—C7	103.49 (9)	C8—C7—S1	115.96 (15)
C2—C1—C6	122.01 (19)	C9^i—C7—S1	122.24 (14)
C2—C1—Cl1	118.91 (16)	C9—C8—C7	122.29 (18)
C6—C1—Cl1	119.08 (16)	C9—C8—H8	118.9
C1—C2—C3	118.82 (18)	C7—C8—H8	118.9
C1—C2—H2	120.6	C8—C9—C7^i	115.95 (17)
C3—C2—H2	120.6	C7^i—C9—C91	124.97 (18)
C4—C3—C2	119.53 (19)	C8—C9—C91	119.06 (18)
C4—C3—H3	120.2	C9—C91—H91A	109.5
C2—C3—H3	120.2	C9—C91—H91B	109.5
C3—C4—C5	121.12 (19)	H91A—C91—H91B	109.5
C3—C4—S1	119.65 (16)	C9—C91—H91C	109.5
C5—C4—S1	119.21 (14)	H91A—C91—H91C	109.5
C6—C5—C4	119.56 (18)	H91B—C91—H91C	109.5
C6—C5—H5	120.2
C6—C1—C2—C3	1.6 (3)	C4—C5—C6—C1	−0.2 (3)
Cl1—C1—C2—C3	−178.89 (15)	C2—C1—C6—C5	−0.8 (3)
C1—C2—C3—C4	−1.2 (3)	Cl1—C1—C6—C5	179.62 (15)
C2—C3—C4—C5	0.2 (3)	O1—S1—C7—C8	148.45 (15)
C2—C3—C4—S1	−177.68 (15)	O2—S1—C7—C8	17.70 (17)
O1—S1—C4—C3	−4.3 (2)	C4—S1—C7—C8	−96.15 (16)
O2—S1—C4—C3	125.05 (17)	O1—S1—C7—C9^i	−33.78 (19)
C7—S1—C4—C3	−121.19 (17)	O2—S1—C7—C9^i	−164.53 (16)
O1—S1—C4—C5	177.70 (15)	C4—S1—C7—C9^i	81.62 (17)
O2—S1—C4—C5	−52.91 (18)	C9^i—C7—C8—C9	0.1 (3)
C7—S1—C4—C5	60.85 (17)	S1—C7—C8—C9	177.89 (15)
C3—C4—C5—C6	0.5 (3)	C7—C8—C9—C7^i	−0.1 (3)
S1—C4—C5—C6	178.43 (15)	C7—C8—C9—C91	−178.32 (18)

Symmetry code: (i) −x+1, −y+1, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C2—H2···O2^ii	0.95	2.54	3.254 (3)	132
C3—H3···O1	0.95	2.52	2.910 (3)	105
C8—H8···O2	0.95	2.42	2.859 (2)	108

Symmetry code: (ii) x, y−1, z.