(E)-1,2-Bis(4-methyl-phen-yl)ethane-1,2-dione.

In the mol-ecule of the title compound, C(16)H(14)O(2), a substituted benzil, the dicarbonyl unit has an s-trans conformation. This conformation is substanti-ated by the O-C-C-O torsion angle of 108.16 (15)°. The dihedral angle between the two aromatic rings is 72.00 (6)°. In the crystal structure, neighbouring mol-ecules are linked together by weak inter-molecular C-H⋯O hydrogen bonds and weak inter-molecular C-H⋯π inter-actions. In addition, the crystal structure is further stabilized by inter-molecular π-π inter-actions with centroid-centroid distances in the range 3.6000 (8)-3.8341 (8) Å.

Related literature

For bond-length data, see Allen et al. (1987 ▶). For carbonyl–carbonyl interactions, see Allen et al. (1998 ▶). For related structures and applications, see, for example: Fun & Kia, (2008 ▶); Kaftory & Rubin, (1983 ▶); Frey et al. (1995 ▶); Crowley et al. (1983 ▶); More et al. (1987 ▶); Brown et al. (1965 ▶); Gabe et al. (1981 ▶); Kimura et al. (1979 ▶); Stevens & Dubois (1962 ▶); Shimizu & Bartlett, (1976 ▶); Rubin (1978 ▶).

Experimental

Crystal data

C16H14O2

M = 238.27

Monoclinic,

a = 6.5658 (1) Å

b = 7.0916 (1) Å

c = 26.5958 (5) Å

β = 96.473 (1)°

V = 1230.46 (3) Å3

Z = 4

Mo Kα radiation

μ = 0.08 mm−1

T = 100.0 (1) K

0.30 × 0.22 × 0.09 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer

Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T min = 0.975, T max = 0.993

15023 measured reflections

3562 independent reflections

2473 reflections with I > 2σ(I)

R int = 0.046

Refinement

R[F 2 > 2σ(F 2)] = 0.052

wR(F 2) = 0.129

S = 1.04

3562 reflections

165 parameters

H-atom parameters constrained

Δρmax = 0.34 e Å−3

Δρmin = −0.23 e Å−3

Data collection: APEX2 (Bruker, 2005 ▶); cell refinement: APEX2; data reduction: SAINT (Bruker, 2005 ▶); program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2003 ▶).

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808023386/at2603sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808023386/at2603Isup2.hkl

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

C16H14O2	F000 = 504
Mr = 238.27	Dx = 1.286 Mg m−3
Monoclinic, P21/n	Mo Kα radiation λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 2861 reflections
a = 6.5658 (1) Å	θ = 3.0–29.0º
b = 7.0916 (1) Å	µ = 0.08 mm−1
c = 26.5958 (5) Å	T = 100.0 (1) K
β = 96.473 (1)º	Block, colourless
V = 1230.46 (3) Å3	0.30 × 0.22 × 0.09 mm
Z = 4

Bruker SMART APEXII CCD area-detector diffractometer	3562 independent reflections
Radiation source: fine-focus sealed tube	2473 reflections with I > 2σ(I)
Monochromator: graphite	Rint = 0.046
T = 100.0(1) K	θmax = 30.0º
φ and ω scans	θmin = 3.0º
Absorption correction: multi-scan(SADABS; Bruker, 2005)	h = −9→9
Tmin = 0.975, Tmax = 0.993	k = −9→9
15023 measured reflections	l = −37→37

Refinement on F2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.053	H-atom parameters constrained
wR(F2) = 0.129	w = 1/[σ2(Fo2) + (0.0539P)2 + 0.2688P] where P = (Fo2 + 2Fc2)/3
S = 1.05	(Δ/σ)max < 0.001
3562 reflections	Δρmax = 0.34 e Å−3
165 parameters	Δρmin = −0.23 e Å−3
Primary atom site location: structure-invariant direct methods	Extinction correction: none

Experimental. The low-temperature data was collected with the Oxford Cyrosystem Cobra low-temperature attachment.

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
O1	0.78303 (16)	0.85817 (16)	0.10574 (4)	0.0265 (3)
O2	0.52337 (16)	0.56364 (16)	0.16163 (4)	0.0284 (3)
C1	0.7563 (2)	0.3603 (2)	0.07576 (5)	0.0216 (3)
H1A	0.7585	0.3142	0.1086	0.026*
C2	0.7544 (2)	0.2362 (2)	0.03573 (5)	0.0228 (3)
H2A	0.7572	0.1071	0.0419	0.027*
C3	0.7484 (2)	0.3022 (2)	−0.01380 (5)	0.0211 (3)
C4	0.7468 (2)	0.4963 (2)	−0.02211 (5)	0.0206 (3)
H4A	0.7422	0.5422	−0.0550	0.025*
C5	0.7519 (2)	0.6211 (2)	0.01774 (5)	0.0202 (3)
H5A	0.7533	0.7502	0.0117	0.024*
C6	0.7550 (2)	0.5541 (2)	0.06734 (5)	0.0193 (3)
C7	0.7559 (2)	0.6884 (2)	0.10961 (5)	0.0200 (3)
C8	0.7002 (2)	0.6162 (2)	0.16073 (5)	0.0210 (3)
C9	0.8525 (2)	0.6278 (2)	0.20558 (5)	0.0197 (3)
C10	1.0524 (2)	0.6905 (2)	0.20242 (5)	0.0216 (3)
H10A	1.0934	0.7207	0.1710	0.026*
C11	1.1896 (2)	0.7079 (2)	0.24546 (5)	0.0234 (3)
H11A	1.3223	0.7495	0.2428	0.028*
C12	1.1314 (2)	0.6638 (2)	0.29296 (5)	0.0233 (3)
C13	0.9340 (2)	0.5956 (2)	0.29583 (5)	0.0237 (3)
H13A	0.8949	0.5614	0.3271	0.028*
C14	0.7955 (2)	0.5781 (2)	0.25295 (5)	0.0219 (3)
H14A	0.6641	0.5331	0.2556	0.026*
C15	0.7434 (2)	0.1652 (2)	−0.05715 (6)	0.0273 (4)
H15A	0.7075	0.2309	−0.0885	0.041*
H15B	0.6436	0.0690	−0.0533	0.041*
H15C	0.8761	0.1084	−0.0573	0.041*
C16	1.2805 (3)	0.6890 (3)	0.33977 (6)	0.0316 (4)
H16A	1.2128	0.6629	0.3692	0.047*
H16B	1.3302	0.8164	0.3413	0.047*
H16C	1.3935	0.6038	0.3387	0.047*

	U11	U22	U33	U12	U13	U23
O1	0.0327 (6)	0.0224 (6)	0.0251 (5)	−0.0009 (5)	0.0062 (4)	0.0025 (5)
O2	0.0246 (5)	0.0343 (7)	0.0271 (6)	−0.0046 (5)	0.0065 (4)	0.0017 (5)
C1	0.0216 (7)	0.0247 (8)	0.0185 (6)	0.0009 (6)	0.0020 (5)	0.0042 (6)
C2	0.0222 (7)	0.0208 (8)	0.0254 (7)	0.0003 (6)	0.0027 (6)	0.0019 (6)
C3	0.0152 (6)	0.0268 (8)	0.0213 (7)	0.0002 (6)	0.0028 (5)	−0.0007 (6)
C4	0.0160 (6)	0.0282 (8)	0.0178 (6)	0.0001 (6)	0.0020 (5)	0.0043 (6)
C5	0.0171 (6)	0.0221 (8)	0.0215 (7)	0.0012 (6)	0.0028 (5)	0.0054 (6)
C6	0.0157 (6)	0.0233 (8)	0.0189 (6)	0.0003 (6)	0.0027 (5)	0.0021 (6)
C7	0.0171 (6)	0.0230 (8)	0.0202 (7)	0.0010 (6)	0.0030 (5)	0.0031 (6)
C8	0.0245 (7)	0.0186 (8)	0.0205 (6)	−0.0001 (6)	0.0060 (6)	−0.0002 (6)
C9	0.0245 (7)	0.0154 (7)	0.0199 (6)	0.0012 (6)	0.0059 (5)	0.0001 (6)
C10	0.0257 (7)	0.0211 (8)	0.0192 (6)	0.0011 (6)	0.0073 (6)	0.0022 (6)
C11	0.0218 (7)	0.0216 (8)	0.0272 (7)	−0.0003 (6)	0.0041 (6)	0.0024 (6)
C12	0.0308 (8)	0.0161 (7)	0.0226 (7)	0.0027 (6)	0.0007 (6)	0.0013 (6)
C13	0.0339 (8)	0.0189 (8)	0.0195 (7)	0.0026 (7)	0.0081 (6)	0.0017 (6)
C14	0.0242 (7)	0.0191 (8)	0.0237 (7)	−0.0004 (6)	0.0087 (6)	0.0005 (6)
C15	0.0258 (8)	0.0311 (9)	0.0251 (7)	−0.0013 (7)	0.0037 (6)	−0.0040 (7)
C16	0.0381 (9)	0.0292 (9)	0.0261 (8)	−0.0001 (8)	−0.0032 (7)	0.0022 (7)

O1—C7	1.2231 (18)	C9—C14	1.3992 (18)
O2—C8	1.2221 (17)	C10—C11	1.380 (2)
C1—C2	1.380 (2)	C10—H10A	0.9300
C1—C6	1.393 (2)	C11—C12	1.3960 (19)
C1—H1A	0.9300	C11—H11A	0.9300
C2—C3	1.394 (2)	C12—C13	1.393 (2)
C2—H2A	0.9300	C12—C16	1.505 (2)
C3—C4	1.394 (2)	C13—C14	1.382 (2)
C3—C15	1.505 (2)	C13—H13A	0.9300
C4—C5	1.378 (2)	C14—H14A	0.9300
C4—H4A	0.9300	C15—H15A	0.9600
C5—C6	1.3999 (18)	C15—H15B	0.9600
C5—H5A	0.9300	C15—H15C	0.9600
C6—C7	1.473 (2)	C16—H16A	0.9600
C7—C8	1.5350 (19)	C16—H16B	0.9600
C8—C9	1.470 (2)	C16—H16C	0.9600
C9—C10	1.398 (2)
O1···O2	3.1702 (15)	Cg1···Cg1ii	3.8341 (8)
Cg1···Cg1i	3.6000 (8)
C2—C1—C6	120.39 (13)	C11—C10—C9	120.56 (13)
C2—C1—H1A	119.8	C11—C10—H10A	119.7
C6—C1—H1A	119.8	C9—C10—H10A	119.7
C1—C2—C3	120.77 (15)	C10—C11—C12	120.72 (14)
C1—C2—H2A	119.6	C10—C11—H11A	119.6
C3—C2—H2A	119.6	C12—C11—H11A	119.6
C4—C3—C2	118.69 (13)	C13—C12—C11	118.59 (13)
C4—C3—C15	121.12 (13)	C13—C12—C16	121.20 (13)
C2—C3—C15	120.19 (14)	C11—C12—C16	120.21 (14)
C5—C4—C3	120.87 (13)	C14—C13—C12	121.06 (13)
C5—C4—H4A	119.6	C14—C13—H13A	119.5
C3—C4—H4A	119.6	C12—C13—H13A	119.5
C4—C5—C6	120.22 (14)	C13—C14—C9	120.15 (13)
C4—C5—H5A	119.9	C13—C14—H14A	119.9
C6—C5—H5A	119.9	C9—C14—H14A	119.9
C1—C6—C5	119.05 (13)	C3—C15—H15A	109.5
C1—C6—C7	121.06 (12)	C3—C15—H15B	109.5
C5—C6—C7	119.89 (13)	H15A—C15—H15B	109.5
O1—C7—C6	124.07 (12)	C3—C15—H15C	109.5
O1—C7—C8	117.04 (13)	H15A—C15—H15C	109.5
C6—C7—C8	118.65 (13)	H15B—C15—H15C	109.5
O2—C8—C9	124.19 (12)	C12—C16—H16A	109.5
O2—C8—C7	116.15 (12)	C12—C16—H16B	109.5
C9—C8—C7	119.47 (12)	H16A—C16—H16B	109.5
C10—C9—C14	118.86 (13)	C12—C16—H16C	109.5
C10—C9—C8	121.78 (12)	H16A—C16—H16C	109.5
C14—C9—C8	119.35 (13)	H16B—C16—H16C	109.5
C6—C1—C2—C3	−0.9 (2)	O1—C7—C8—C9	−67.01 (18)
C1—C2—C3—C4	0.8 (2)	C6—C7—C8—C9	118.41 (15)
C1—C2—C3—C15	−179.15 (13)	O2—C8—C9—C10	−179.46 (15)
C2—C3—C4—C5	0.3 (2)	C7—C8—C9—C10	−4.7 (2)
C15—C3—C4—C5	−179.83 (13)	O2—C8—C9—C14	−0.6 (2)
C3—C4—C5—C6	−1.2 (2)	C7—C8—C9—C14	174.18 (13)
C2—C1—C6—C5	0.0 (2)	C14—C9—C10—C11	−1.8 (2)
C2—C1—C6—C7	179.66 (13)	C8—C9—C10—C11	177.11 (14)
C4—C5—C6—C1	1.0 (2)	C9—C10—C11—C12	−0.1 (2)
C4—C5—C6—C7	−178.64 (12)	C10—C11—C12—C13	2.2 (2)
C1—C6—C7—O1	169.54 (14)	C10—C11—C12—C16	−178.16 (14)
C5—C6—C7—O1	−10.8 (2)	C11—C12—C13—C14	−2.3 (2)
C1—C6—C7—C8	−16.28 (19)	C16—C12—C13—C14	178.02 (14)
C5—C6—C7—C8	163.39 (12)	C12—C13—C14—C9	0.4 (2)
O1—C7—C8—O2	108.17 (16)	C10—C9—C14—C13	1.6 (2)
C6—C7—C8—O2	−66.42 (18)	C8—C9—C14—C13	−177.28 (13)

D—H···A	D—H	H···A	D···A	D—H···A
C2—H2A···O1iii	0.93	2.44	3.2573 (18)	146
C14—H14A···Cg2iv	0.93	2.94	3.6105 (15)	130

Cg1 is the centroid of the C1–C6 benzene ring.

C7—C8

1.5350 (19)

O1⋯O2	3.1702 (15)
Cg1⋯Cg1i	3.6000 (8)
Cg1⋯Cg1ii	3.8341 (8)

Symmetry codes: (i) ; (ii) .

Table 2

Hydrogen-bond geometry (Å, °)

Cg2 is the centroid of the C9–C14 benzene ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C2—H2A⋯O1iii	0.93	2.44	3.2573 (18)	146
C14—H14A⋯Cg2iv	0.93	2.94	3.6105 (15)	130

Symmetry codes: (iii) ; (iv) .