3,4-Diphenyl-2,5-bis­(trimethyl­silyl)cyclo­penta­dienone

In the title compound, C₂₃H₂₈OSi₂, the five-membered ring is essentially planar and the phenyl rings are oriented with respect to the mean plane of this ring by 56.01 (3) and 56.68 (4)°.

Key indicators

• Single-crystal X-ray study
• T = 103 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.028
• wR factor = 0.075
• Data-to-parameter ratio = 21.9

checkCIF/PLATON results

No syntax errors found



Alert level C
            Value of measurement temperature given =   103.000
            Value of melting point given =     0.000
PLAT230_ALERT_2_C Hirshfeld Test Diff for    O1     --  C1      ..       5.14 su
PLAT369_ALERT_2_C Long   C(sp2)-C(sp2) Bond  C3     -   C4     ...       1.53 Ang.
PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical .          ?

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           27.93
           From the CIF: _reflns_number_total               5286
           Count of symmetry unique reflns         2994
           Completeness (_total/calc)            176.55%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured      2292
           Fraction of Friedel pairs measured     0.766
           Are heavy atom types Z>Si present        yes

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   3 ALERT level C = Check and explain
   1 ALERT level G = General alerts; check

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   2 ALERT type 2 Indicator that the structure model may be wrong or deficient
   0 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

---

S1. Comment

Although the synthesis of the title compound, (I), was already reported (Rajesh & Periasamy, 1999), the reported NMR data were incorrect. Thus, we report herein the molecular structure of the title compound and revise its NMR data. The five-membered ring and four bonds derived from the each of carbon atoms in the five-membered ring are situated in a planar geometry, as was observed in the tetraphenylcyclopentadienone (Barnes et al., 1991). Bond alternation of the C—C bonds in the five-membered ring of (I) is found, as was observed in other cyclopentadienones (Barnes et al., 1991; Ruffani et al., 2006). The C1—O1 distance (1.2139 (15) Å) in (I), is quite similar to that found in the tetraphenyl derivative (Barnes et al., 1991).

Related literature

For a previous report of the synthesis of the title compound, see: Rajesh & Periasamy (1999). For related structures, see: Barnes et al. (1991); Ruffani et al. (2006). [Please check added text]

S2. Experimental

To lithium (32 mg, 4.61 mmol) was added a diethyl ether (2.5 ml) solution of phenyl(trimethylsilyl)acetylene (408 mg, 2.34 mmol) and the resulting mixture was stirred at room temperature for 4 h. To an ether solution of 1,4-dilithio-1,3-butadiene thus obtained was added diethyl ether (8 ml) and unreacted lithium was removed by filtration. Carbon dioxide was bubbled into the filtrate at room temperature for 1 min. After treatment of the resulting mixture with hydrochloric acid (3 N), the organic layer was extracted with diethyl ether and dried over anhydrous magnesium sulfate. After removal of volatile substances, the residue was subjected to column chromatography (SiO₂, hexane:ethyl acetate = 30:1) to afford the title compound, 3,4-diphenyl-2,5-bis(trimethylsilyl)cyclopentadienone (I) (22 mg, 5%). Suitable crystals for X-ray crystallographic analysis were obtained by slow evaporation of a hexane solution of (I).

S3. Refinement

Hydrogen atoms attached to C(sp³) and C(sp²) carbon atoms were treated as riding with C—H distances of 0.96 and 0.93 Å, respectively, and were included in the final cycles of least squares with isotropic Uijs by using a riding model, while all the other atoms were refined anisotropically.

Computing details

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT (Bruker, 2000); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures

Fig. 1. A view of the molecule of (I) showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 40% probability level.

3,4-Diphenyl-2,5-bis(trimethylsilyl)cyclopentadienone

Crystal data

C23H28OSi2	F(000) = 808
Mr = 376.63	Dx = 1.132 Mg m^−3
Orthorhombic, P212121	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2ab	Cell parameters from 5798 reflections
a = 9.8418 (6) Å	θ = 2.7–27.9°
b = 11.8041 (7) Å	µ = 0.17 mm^−1
c = 19.0181 (12) Å	T = 103 K
V = 2209.4 (2) Å^3	Cube, orange
Z = 4	0.50 × 0.40 × 0.40 mm

Data collection

Bruker SMART CCD area-detector diffractometer	5286 independent reflections
Radiation source: fine-focus sealed tube	5181 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.021
ϕ and ω scans	θmax = 27.9°, θmin = 2.0°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −12→11
Tmin = 0.922, Tmax = 0.935	k = −15→15
16200 measured reflections	l = −21→25

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)] = 0.028	H-atom parameters constrained
wR(F^2) = 0.075	w = 1/[σ^2(Fo^2) + (0.0473P)^2 + 0.2508P] where P = (Fo^2 + 2Fc^2)/3
S = 1.07	(Δ/σ)max = 0.001
5286 reflections	Δρmax = 0.28 e Å^−3
241 parameters	Δρmin = −0.20 e Å^−3
0 restraints	Absolute structure: Flack (1983), with 2292 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.01 (6)

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. The Flack parameter was not changed after least-square refinement without merging the reflections. When the refinement was carried out using the opposite absolute structure, the Flack parameter was 0.99 (7).

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

	x	y	z	Uiso*/Ueq
Si1	0.18748 (3)	1.12044 (3)	0.976841 (17)	0.01882 (8)
Si2	0.42760 (3)	0.77489 (3)	0.787011 (18)	0.02008 (8)
O1	0.42093 (9)	1.01676 (8)	0.87657 (5)	0.0272 (2)
C2	0.18860 (12)	0.99471 (10)	0.91621 (6)	0.0180 (2)
C15	0.08537 (12)	0.72378 (10)	0.82868 (6)	0.0190 (2)
C7	0.03840 (14)	1.11986 (13)	1.03721 (7)	0.0289 (3)
H7A	0.0361	1.0497	1.0627	0.043*
H7B	−0.0436	1.1278	1.0103	0.043*
H7C	0.0459	1.1818	1.0697	0.043*
C3	0.09673 (12)	0.91490 (9)	0.89917 (6)	0.0176 (2)
C6	0.18912 (15)	1.25143 (10)	0.92156 (7)	0.0267 (3)
H6A	0.1116	1.2513	0.8909	0.040*
H6B	0.2708	1.2533	0.8940	0.040*
H6C	0.1858	1.3170	0.9514	0.040*
C16	−0.03609 (13)	0.73727 (11)	0.79091 (7)	0.0229 (2)
H16	−0.0694	0.8096	0.7819	0.028*
C12	−0.31728 (13)	0.90660 (12)	0.96478 (7)	0.0263 (3)
H12	−0.4070	0.9059	0.9802	0.032*
C9	−0.04729 (11)	0.91027 (10)	0.92063 (6)	0.0181 (2)
C10	−0.13363 (12)	1.00076 (11)	0.90568 (6)	0.0209 (2)
H10	−0.1009	1.0628	0.8807	0.025*
C14	−0.09904 (13)	0.81670 (11)	0.95650 (6)	0.0227 (2)
H14	−0.0432	0.7548	0.9654	0.027*
C4	0.16243 (12)	0.82381 (10)	0.85340 (6)	0.0181 (2)
C18	−0.06037 (15)	0.53448 (11)	0.78188 (7)	0.0290 (3)
H18	−0.1087	0.4716	0.7662	0.035*
C8	0.34391 (14)	1.11229 (13)	1.03210 (7)	0.0318 (3)
H8A	0.3455	1.1748	1.0644	0.048*
H8B	0.4227	1.1154	1.0024	0.048*
H8C	0.3440	1.0424	1.0580	0.048*
C1	0.31734 (12)	0.96101 (10)	0.87823 (6)	0.0191 (2)
C20	0.13106 (14)	0.61403 (11)	0.84330 (7)	0.0228 (2)
H20	0.2109	0.6037	0.8686	0.027*
C22	0.55418 (15)	0.87927 (12)	0.75313 (8)	0.0333 (3)
H22A	0.6181	0.8412	0.7232	0.050*
H22B	0.6015	0.9131	0.7919	0.050*
H22C	0.5081	0.9371	0.7269	0.050*
C13	−0.23314 (13)	0.81532 (12)	0.97897 (7)	0.0271 (3)
H13	−0.2665	0.7532	1.0035	0.033*
C11	−0.26813 (13)	0.99900 (12)	0.92774 (7)	0.0241 (3)
H11	−0.3251	1.0597	0.9177	0.029*
C5	0.29427 (12)	0.84939 (10)	0.84058 (6)	0.0185 (2)
C23	0.34694 (14)	0.70279 (12)	0.71046 (7)	0.0292 (3)
H23A	0.4161	0.6693	0.6816	0.044*
H23B	0.2967	0.7571	0.6834	0.044*
H23C	0.2865	0.6448	0.7270	0.044*
C19	0.05826 (15)	0.52031 (11)	0.82031 (7)	0.0284 (3)
H19	0.0891	0.4478	0.8307	0.034*
C17	−0.10663 (13)	0.64309 (12)	0.76695 (7)	0.0275 (3)
H17	−0.1855	0.6527	0.7407	0.033*
C21	0.51771 (14)	0.67089 (12)	0.84432 (8)	0.0287 (3)
H21A	0.4534	0.6176	0.8630	0.043*
H21B	0.5612	0.7102	0.8823	0.043*
H21C	0.5849	0.6313	0.8172	0.043*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Si1	0.01810 (15)	0.01801 (15)	0.02036 (15)	−0.00020 (12)	−0.00082 (12)	−0.00287 (12)
Si2	0.02101 (15)	0.01866 (15)	0.02057 (15)	0.00210 (12)	0.00300 (12)	−0.00136 (12)
O1	0.0186 (4)	0.0265 (4)	0.0366 (5)	−0.0041 (4)	0.0035 (4)	−0.0071 (4)
C2	0.0175 (5)	0.0178 (5)	0.0188 (5)	0.0023 (4)	−0.0003 (4)	−0.0005 (4)
C15	0.0209 (5)	0.0197 (5)	0.0164 (5)	−0.0020 (5)	0.0017 (4)	−0.0011 (4)
C7	0.0289 (6)	0.0320 (7)	0.0257 (6)	−0.0020 (6)	0.0058 (5)	−0.0061 (5)
C3	0.0185 (5)	0.0167 (5)	0.0175 (5)	0.0021 (4)	−0.0003 (4)	0.0020 (4)
C6	0.0322 (6)	0.0188 (6)	0.0291 (6)	−0.0009 (5)	0.0004 (5)	−0.0004 (4)
C16	0.0236 (6)	0.0232 (6)	0.0220 (5)	−0.0004 (5)	−0.0011 (5)	−0.0002 (5)
C12	0.0178 (5)	0.0358 (7)	0.0253 (6)	−0.0019 (5)	0.0025 (5)	0.0021 (5)
C9	0.0171 (5)	0.0196 (5)	0.0175 (5)	−0.0005 (4)	−0.0025 (4)	−0.0023 (4)
C10	0.0200 (5)	0.0204 (5)	0.0224 (5)	−0.0003 (5)	−0.0006 (4)	0.0025 (4)
C14	0.0232 (6)	0.0230 (6)	0.0219 (6)	0.0017 (5)	0.0000 (5)	0.0042 (4)
C4	0.0216 (6)	0.0166 (5)	0.0162 (5)	0.0022 (4)	−0.0010 (4)	0.0015 (4)
C18	0.0361 (7)	0.0251 (6)	0.0256 (6)	−0.0110 (5)	0.0011 (6)	−0.0062 (5)
C8	0.0267 (6)	0.0374 (7)	0.0315 (7)	0.0009 (6)	−0.0092 (5)	−0.0060 (6)
C1	0.0180 (5)	0.0190 (5)	0.0202 (5)	0.0028 (4)	−0.0005 (4)	0.0008 (4)
C20	0.0265 (6)	0.0207 (6)	0.0211 (5)	−0.0003 (5)	−0.0004 (5)	−0.0003 (5)
C22	0.0341 (7)	0.0291 (6)	0.0367 (7)	−0.0043 (6)	0.0147 (6)	−0.0016 (6)
C13	0.0251 (6)	0.0316 (7)	0.0246 (6)	−0.0039 (5)	0.0021 (5)	0.0075 (5)
C11	0.0194 (6)	0.0264 (6)	0.0264 (6)	0.0035 (5)	−0.0020 (5)	0.0007 (5)
C5	0.0205 (6)	0.0167 (5)	0.0183 (5)	0.0015 (4)	−0.0007 (4)	0.0002 (4)
C23	0.0331 (7)	0.0327 (7)	0.0217 (6)	−0.0001 (5)	0.0027 (5)	−0.0064 (5)
C19	0.0383 (7)	0.0183 (6)	0.0285 (6)	−0.0024 (5)	0.0024 (6)	−0.0005 (5)
C17	0.0251 (6)	0.0340 (7)	0.0234 (6)	−0.0052 (5)	−0.0028 (5)	−0.0023 (5)
C21	0.0269 (6)	0.0269 (6)	0.0323 (7)	0.0074 (5)	−0.0012 (5)	0.0004 (5)

Geometric parameters (Å, º)

Si1—C7	1.8630 (13)	C9—C14	1.3946 (17)
Si1—C8	1.8666 (14)	C10—C11	1.3887 (17)
Si1—C6	1.8699 (13)	C10—H10	0.9300
Si1—C2	1.8795 (12)	C14—C13	1.3873 (19)
Si2—C23	1.8640 (14)	C14—H14	0.9300
Si2—C21	1.8659 (14)	C4—C5	1.3544 (17)
Si2—C22	1.8668 (14)	C18—C19	1.388 (2)
Si2—C5	1.8796 (12)	C18—C17	1.390 (2)
O1—C1	1.2139 (15)	C18—H18	0.9300
C2—C3	1.3454 (16)	C8—H8A	0.9600
C2—C1	1.5117 (16)	C8—H8B	0.9600
C15—C20	1.3993 (17)	C8—H8C	0.9600
C15—C16	1.4037 (17)	C1—C5	1.5166 (16)
C15—C4	1.4799 (16)	C20—C19	1.3886 (18)
C7—H7A	0.9600	C20—H20	0.9300
C7—H7B	0.9600	C22—H22A	0.9600
C7—H7C	0.9600	C22—H22B	0.9600
C3—C9	1.4760 (16)	C22—H22C	0.9600
C3—C4	1.5271 (16)	C13—H13	0.9300
C6—H6A	0.9600	C11—H11	0.9300
C6—H6B	0.9600	C23—H23A	0.9600
C6—H6C	0.9600	C23—H23B	0.9600
C16—C17	1.3876 (18)	C23—H23C	0.9600
C16—H16	0.9300	C19—H19	0.9300
C12—C11	1.3855 (19)	C17—H17	0.9300
C12—C13	1.3855 (19)	C21—H21A	0.9600
C12—H12	0.9300	C21—H21B	0.9600
C9—C10	1.3942 (16)	C21—H21C	0.9600
C7—Si1—C8	107.60 (6)	C15—C4—C3	121.72 (10)
C7—Si1—C6	110.88 (7)	C19—C18—C17	119.63 (12)
C8—Si1—C6	110.62 (7)	C19—C18—H18	120.2
C7—Si1—C2	112.32 (6)	C17—C18—H18	120.2
C8—Si1—C2	107.45 (6)	Si1—C8—H8A	109.5
C6—Si1—C2	107.94 (5)	Si1—C8—H8B	109.5
C23—Si2—C21	110.99 (6)	H8A—C8—H8B	109.5
C23—Si2—C22	108.42 (7)	Si1—C8—H8C	109.5
C21—Si2—C22	108.58 (7)	H8A—C8—H8C	109.5
C23—Si2—C5	109.86 (6)	H8B—C8—H8C	109.5
C21—Si2—C5	108.84 (6)	O1—C1—C2	125.01 (11)
C22—Si2—C5	110.13 (6)	O1—C1—C5	125.76 (11)
C3—C2—C1	105.30 (10)	C2—C1—C5	109.19 (10)
C3—C2—Si1	134.17 (9)	C19—C20—C15	120.61 (12)
C1—C2—Si1	120.39 (8)	C19—C20—H20	119.7
C20—C15—C16	118.71 (11)	C15—C20—H20	119.7
C20—C15—C4	120.72 (11)	Si2—C22—H22A	109.5
C16—C15—C4	120.56 (11)	Si2—C22—H22B	109.5
Si1—C7—H7A	109.5	H22A—C22—H22B	109.5
Si1—C7—H7B	109.5	Si2—C22—H22C	109.5
H7A—C7—H7B	109.5	H22A—C22—H22C	109.5
Si1—C7—H7C	109.5	H22B—C22—H22C	109.5
H7A—C7—H7C	109.5	C12—C13—C14	119.96 (12)
H7B—C7—H7C	109.5	C12—C13—H13	120.0
C2—C3—C9	127.20 (11)	C14—C13—H13	120.0
C2—C3—C4	110.23 (10)	C12—C11—C10	119.88 (12)
C9—C3—C4	122.56 (10)	C12—C11—H11	120.1
Si1—C6—H6A	109.5	C10—C11—H11	120.1
Si1—C6—H6B	109.5	C4—C5—C1	104.61 (10)
H6A—C6—H6B	109.5	C4—C5—Si2	131.46 (9)
Si1—C6—H6C	109.5	C1—C5—Si2	123.91 (9)
H6A—C6—H6C	109.5	Si2—C23—H23A	109.5
H6B—C6—H6C	109.5	Si2—C23—H23B	109.5
C17—C16—C15	120.21 (11)	H23A—C23—H23B	109.5
C17—C16—H16	119.9	Si2—C23—H23C	109.5
C15—C16—H16	119.9	H23A—C23—H23C	109.5
C11—C12—C13	120.17 (12)	H23B—C23—H23C	109.5
C11—C12—H12	119.9	C18—C19—C20	120.27 (12)
C13—C12—H12	119.9	C18—C19—H19	119.9
C10—C9—C14	118.95 (11)	C20—C19—H19	119.9
C10—C9—C3	120.03 (11)	C16—C17—C18	120.54 (12)
C14—C9—C3	121.02 (11)	C16—C17—H17	119.7
C11—C10—C9	120.52 (12)	C18—C17—H17	119.7
C11—C10—H10	119.7	Si2—C21—H21A	109.5
C9—C10—H10	119.7	Si2—C21—H21B	109.5
C13—C14—C9	120.49 (12)	H21A—C21—H21B	109.5
C13—C14—H14	119.8	Si2—C21—H21C	109.5
C9—C14—H14	119.8	H21A—C21—H21C	109.5
C5—C4—C15	127.71 (11)	H21B—C21—H21C	109.5
C5—C4—C3	110.56 (10)