1,4-Bis(4-chloro-phenyl-seleno)-2,5-di-methoxy-benzene.

The title compound, C(20)H(16)Cl(2)O(2)Se(2), utilizes the symmetry of the crystallographic inversion center. Mol-ecular chains are formed through symmetric C-H⋯Cl inter-actions 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 = 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) Å3

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

Δρmax = 0.59 e Å−3

Δρmin = −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.

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808039469/sg2281sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808039469/sg2281Isup2.hkl

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

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

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 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)

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.

	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*

	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)

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)