1,4-Bis(4-chloro­phenyl­seleno)-2,5-di­methoxy­benzene

Abstract

The title compound, C₂₀H₁₆Cl₂O₂Se₂, utilizes the symmetry of the crystallographic inversion center. Mol­ecular chains are formed through symmetric C—H⋯Cl inter­actions around inversion centers, mimicking the commonly observed symmetric hydrogen-bonded dimer pattern often found in carboxylic acids.

Related literature

For background to the electrophilic aryl­selenylation of reactive arenes, see: Santi et al. (2008 ▶); Nicolaou et al. (1979 ▶); Gassman et al. (1982 ▶); Yoshida et al. (1991 ▶); Tiecco et al. (1994 ▶); Engman & Eriksson (1996 ▶); Henriksen (1994 ▶); Henriksen & Stuhr-Hansen (1998 ▶). For related structures, see: Oddershede et al. (2003 ▶). For related supra­molecular patterns, see: Gavezzotti & Filippini (1994 ▶); Allen et al. (1999 ▶); Sørensen & Larsen (2003 ▶); Sørensen et al. (1999 ▶).

Experimental

Crystal data

• C₂₀H₁₆Cl₂O₂Se₂

• M _r = 517.15

• Monoclinic,

• a = 11.7737 (17) Å

• b = 6.6535 (6) Å

• c = 13.438 (5) Å

• β = 114.136 (16)°

• V = 960.7 (4) ų

• Z = 2

• Cu Kα radiation

• μ = 7.47 mm⁻¹

• T = 122 (1) K

• 0.44 × 0.15 × 0.13 mm

Data collection

• Enraf–Nonius CAD-4 diffractometer

• Absorption correction: gaussian (DeTitta, 1985 ▶). T _min = 0.242, T _max = 0.796

• 2641 measured reflections

• 1976 independent reflections

• 1919 reflections with I > 2σ(I)

• R _int = 0.030

• 5 standard reflections frequency: 166.7 min intensity decay: 5.7%

Refinement

• R[F ² > 2σ(F ²)] = 0.028

• wR(F ²) = 0.075

• S = 1.10

• 1976 reflections

• 119 parameters

• H-atom parameters constrained

• Δρ_max = 0.59 e Å⁻³

• Δρ_min = −1.20 e Å⁻³

Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994 ▶); cell refinement: CAD-4 EXPRESS; data reduction: DREAR (Blessing, 1987 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: PLATON (Spek, 2003 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

supplementary crystallographic information

Comment

The structure of the title compound, shown in Fig. 1, crystallized in space group P 2₁/n utilizing the crystallography inversion center in the molecular symmetry. Generally the molecular geometry of 1 is in close agreement with the related compound 1,3-dimethoxy-4,6-bis(phenylseleno)benzene, hereafter DMPSB. All bond distances and angles are the same within the experimental uncertainty. The molecular conformation of 1 is also very similar to the chloro-unsubstituted compound DMPSB having the planes of phenylseleno groups arranged perpendicular to the plane of the central benzene moiety, but rotated in opposite directions forming a Z like conformation (Fig. 1). Leading to the formation of intramolecular C_ar—H···π interactions.

The molecular packing arrangement is dominated by molecular chains (see Fig. 2) formed by cyclic C_ar—H···Cl interactions [H7···Cl_i = 2.96 Å, C7—H7···Cl_i = 166.0°; symmetry code: (i) 2 - x,1 - y,1 - z] around an inversion center leading to a pattern, which highly resembles the cyclic hydrogen-bonded dimers frequently observed in carboxylic acids. The C_ar—H···Cl type of cyclic interaction found in 1 has also been observed in other compounds having a p-chlorosubstituted phenyl group, e.g. in the structure of racemic p-chlorophenoxypropionic acid, where the distance H···Cl is 2.92 Å [C—H···Cl 175°]. The chains are stacked such that the π-π interactions between the phenelseleno groups and between the benzene rings along the diagonal of the b and c-axes, respectively. Due to the chain formation in 1 the packing arrangement is rather different from the pattern found in DMPSB, where interactions with chlorine cannot be formed.

Experimental

Crystals suitable for an X-ray diffraction experiment were obtained by slow crystallization from hot toluene.

Refinement

Hydrogen atoms of (1) were found in the difference Fourier map. All hydrogen atoms were treated as riding atoms with C—H distances of 0.95 for C_ar and 0.98 for the C_Me. Isotropic displacement parameters for all H atoms were constrained to 1.2U_eq of the connected non-hydrogen atom (1.5U_eq for Me groups).

Figures

Fig. 1.

Thermal elipsoid plot of (1) including labelling of the atoms. The displacement ellipsoids are drawn at the 50% probability level. H atoms are shown as spheres with an arbitrary radii.

Fig. 2.

A view of the cyclic C—H···Cl interactions linking the molecules into a chain.

Fig. 3.

Packing diagram of viewed down the b axis.

Crystal data

C20H16Cl2O2Se2	F(000) = 508
Mr = 517.15	Dx = 1.788 Mg m−3
Monoclinic, P21/n	Melting point: 193 K
Hall symbol: -P 2yn	Cu Kα radiation, λ = 1.54184 Å
a = 11.7737 (17) Å	Cell parameters from 20 reflections
b = 6.6535 (6) Å	θ = 39.3–40.7°
c = 13.438 (5) Å	µ = 7.47 mm−1
β = 114.136 (16)°	T = 122 K
V = 960.7 (4) Å3	Block, white
Z = 2	0.44 × 0.15 × 0.13 mm

Data collection

Enraf–Nonius CAD-4 diffractometer	1919 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.030
graphite	θmax = 74.9°, θmin = 4.2°
ω–2θ scans	h = −14→14
Absorption correction: gaussian (DeTitta, 1985).	k = −7→8
Tmin = 0.242, Tmax = 0.796	l = 0→16
2641 measured reflections	5 standard reflections every 166.7 min
1976 independent reflections	intensity decay: 5.7%

Refinement

Refinement on F2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.028	H-atom parameters constrained
wR(F2) = 0.076	w = 1/[σ2(Fo2) + (0.0433P)2 + 0.9774P] where P = (Fo2 + 2Fc2)/3
S = 1.10	(Δ/σ)max < 0.001
1976 reflections	Δρmax = 0.60 e Å−3
119 parameters	Δρmin = −1.20 e Å−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0029 (3)

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
Se1	0.745362 (19)	0.19839 (3)	0.007848 (17)	0.01812 (12)
Cl	1.00097 (5)	0.82041 (8)	0.40315 (5)	0.02427 (15)
O1	1.23891 (13)	0.1213 (2)	0.13084 (12)	0.0192 (3)
C1	1.2567 (2)	0.2869 (3)	0.20396 (19)	0.0232 (5)
H1A	1.3459	0.3140	0.2431	0.035*
H1B	1.2213	0.2535	0.2564	0.035*
H1C	1.2150	0.4063	0.1623	0.035*
C2	1.11846 (19)	0.0668 (3)	0.06767 (16)	0.0160 (4)
C3	1.0144 (2)	0.1577 (3)	0.07253 (17)	0.0168 (4)
H3	1.0245	0.2653	0.1219	0.020*
C4	0.89557 (19)	0.0910 (3)	0.00514 (16)	0.0159 (4)
C5	0.82080 (19)	0.3830 (3)	0.12694 (17)	0.0172 (4)
C6	0.8614 (2)	0.3181 (3)	0.23448 (19)	0.0194 (4)
H6	0.8506	0.1815	0.2493	0.023*
C7	0.9173 (2)	0.4513 (3)	0.32023 (17)	0.0197 (4)
H7	0.9457	0.4067	0.3936	0.024*
C8	0.93109 (19)	0.6504 (3)	0.29699 (17)	0.0174 (4)
C9	0.8891 (2)	0.7196 (3)	0.19057 (19)	0.0211 (5)
H9	0.8985	0.8570	0.1762	0.025*
C10	0.8331 (2)	0.5850 (3)	0.10537 (17)	0.0201 (4)
H10	0.8030	0.6308	0.0321	0.024*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Se1	0.01674 (16)	0.01956 (17)	0.01817 (16)	0.00021 (7)	0.00723 (11)	−0.00363 (7)
Cl	0.0267 (3)	0.0243 (3)	0.0206 (3)	−0.0041 (2)	0.0084 (2)	−0.00601 (18)
O1	0.0174 (7)	0.0196 (7)	0.0194 (7)	−0.0023 (6)	0.0063 (6)	−0.0059 (6)
C1	0.0242 (11)	0.0227 (11)	0.0217 (11)	−0.0045 (9)	0.0084 (9)	−0.0084 (8)
C2	0.0178 (9)	0.0154 (9)	0.0145 (9)	−0.0025 (8)	0.0064 (7)	0.0012 (7)
C3	0.0215 (10)	0.0136 (9)	0.0164 (9)	−0.0016 (8)	0.0089 (8)	−0.0014 (7)
C4	0.0192 (9)	0.0143 (9)	0.0156 (9)	0.0004 (7)	0.0084 (8)	0.0013 (7)
C5	0.0169 (9)	0.0178 (10)	0.0196 (10)	0.0013 (8)	0.0103 (8)	−0.0016 (8)
C6	0.0211 (10)	0.0160 (10)	0.0216 (11)	0.0022 (8)	0.0091 (9)	0.0024 (8)
C7	0.0208 (10)	0.0215 (11)	0.0170 (9)	0.0033 (8)	0.0080 (8)	0.0037 (8)
C8	0.0169 (9)	0.0173 (10)	0.0189 (10)	0.0001 (8)	0.0080 (8)	−0.0038 (8)
C9	0.0255 (11)	0.0163 (10)	0.0213 (11)	−0.0001 (8)	0.0093 (9)	0.0018 (8)
C10	0.0245 (11)	0.0196 (10)	0.0170 (10)	0.0017 (8)	0.0093 (8)	0.0031 (8)

Geometric parameters (Å, °)

Se1—C4	1.921 (2)	C4—C2i	1.398 (3)
Se1—C5	1.923 (2)	C5—C6	1.393 (3)
Cl—C8	1.741 (2)	C5—C10	1.395 (3)
O1—C2	1.371 (2)	C6—C7	1.388 (3)
O1—C1	1.433 (2)	C6—H6	0.9500
C1—H1A	0.9800	C7—C8	1.386 (3)
C1—H1B	0.9800	C7—H7	0.9500
C1—H1C	0.9800	C8—C9	1.387 (3)
C2—C3	1.391 (3)	C9—C10	1.389 (3)
C2—C4i	1.398 (3)	C9—H9	0.9500
C3—C4	1.392 (3)	C10—H10	0.9500
C3—H3	0.9500
C4—Se1—C5	97.92 (9)	C6—C5—Se1	120.74 (16)
C2—O1—C1	116.88 (17)	C10—C5—Se1	119.64 (16)
O1—C1—H1A	109.5	C7—C6—C5	120.6 (2)
O1—C1—H1B	109.5	C7—C6—H6	119.7
H1A—C1—H1B	109.5	C5—C6—H6	119.7
O1—C1—H1C	109.5	C8—C7—C6	118.9 (2)
H1A—C1—H1C	109.5	C8—C7—H7	120.6
H1B—C1—H1C	109.5	C6—C7—H7	120.6
O1—C2—C3	124.29 (19)	C7—C8—C9	121.7 (2)
O1—C2—C4i	115.37 (18)	C7—C8—Cl	119.75 (17)
C3—C2—C4i	120.34 (19)	C9—C8—Cl	118.60 (17)
C2—C3—C4	120.07 (19)	C8—C9—C10	119.0 (2)
C2—C3—H3	120.0	C8—C9—H9	120.5
C4—C3—H3	120.0	C10—C9—H9	120.5
C3—C4—C2i	119.60 (19)	C9—C10—C5	120.3 (2)
C3—C4—Se1	123.88 (16)	C9—C10—H10	119.9
C2i—C4—Se1	116.50 (15)	C5—C10—H10	119.9
C6—C5—C10	119.6 (2)
C1—O1—C2—C3	−1.8 (3)	C10—C5—C6—C7	−2.0 (3)
C1—O1—C2—C4i	178.06 (18)	Se1—C5—C6—C7	179.10 (16)
O1—C2—C3—C4	−179.78 (19)	C5—C6—C7—C8	0.6 (3)
C4i—C2—C3—C4	0.4 (3)	C6—C7—C8—C9	0.8 (3)
C2—C3—C4—C2i	−0.4 (3)	C6—C7—C8—Cl	179.98 (16)
C2—C3—C4—Se1	177.83 (15)	C7—C8—C9—C10	−0.7 (3)
C5—Se1—C4—C3	−3.27 (19)	Cl—C8—C9—C10	−179.91 (17)
C5—Se1—C4—C2i	174.97 (16)	C8—C9—C10—C5	−0.8 (3)
C4—Se1—C5—C6	−83.67 (18)	C6—C5—C10—C9	2.1 (3)
C4—Se1—C5—C10	97.46 (18)	Se1—C5—C10—C9	−179.02 (17)

Symmetry codes: (i) −x+2, −y, −z.