Methyl 4-(trimethyl­silylethyn­yl)benzoate

The title compound, C₁₃H₁₆O₂Si, was synthesized as a precursor for ethynylarene derivatives and crystallized from hexane. In the crystal structure, mol­ecules are linked by weak C—H...O hydrogen bonds to form chains that pack in layers in a herringbone fashion.

Key indicators

• Single-crystal X-ray study
• T = 100 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.059
• wR factor = 0.115
• Data-to-parameter ratio = 20.5

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical .          ?
PLAT230_ALERT_2_C Hirshfeld Test Diff for    Si1    -   C10     ..       5.70 su
PLAT371_ALERT_2_C Long   C(sp2)-C(sp1) Bond  C4     -   C9     ...       1.44 Ang.

Alert level G
REFLT03_ALERT_1_G ALERT: Expected hkl max differ from CIF values
           From the CIF: _diffrn_reflns_theta_max           28.25
           From the CIF: _reflns_number_total               3050
           From the CIF: _diffrn_reflns_limit_ max hkl    8.    9.   32.
           From the CIF: _diffrn_reflns_limit_ min hkl   -7.   -8.  -37.
           TEST1: Expected hkl limits for theta max
           Calculated maximum hkl    8.    9.   39.
           Calculated minimum hkl   -8.   -9.  -39.
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           28.25
           From the CIF: _reflns_number_total               3050
           Count of symmetry unique reflns         1914
           Completeness (_total/calc)            159.35%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured      1136
           Fraction of Friedel pairs measured     0.594
           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
   2 ALERT level G = General alerts; check

   2 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

The title compound was isolated as a precursor in the synthesis of a series of ethynylarene-based ligands with terminal carboxylate groups. Interest in these kinds of ligands can be attributed to their ability to incorporate metal ions into M—O—C clusters, leading to novel metal-organic frameworks (MOFs), a category of compounds gaining increasing interest due to their potential applications for gas storage and separation and catalysis (Eddaoudi et al., 2001; Dybtsev et al., 2004; Kesanli et al., 2005; Zhao et al., 2004). The structure of the title compound (I) is shown in Fig. 1. Molecules of (I) pack in layers parallel to the (010) plane forming herring-bone motifs (Fig. 2). Analysis of the crystal packing shows that the molecules are arranged in alternating directions in the layer, due to the bulky trimethylsilyl groups facilitating the close packing of the molecules with the adjacent layer along the c axis. The methyl hydrogen atoms of the trimethysilyl group form C—H···O hydrogen bonds with the carbonyl oxygen atom on the adjacent molecule (Fig. 3).

The acetylenic bond distance [C9—C10 1.200 (3) Å] corresponds with the average value detailed in Allen et al. (1987) for C_sp≡ C_sp–C_sp2 (Ar).

Related literature

For related literature, see: Eddaoudi et al. (2001); Dybtsev et al. (2004); Kesanli et al. (2005); Zhao et al. (2004); Allen et al. (1987); Fasina et al. (2005).

S2. Experimental

The title compound (I), was synthesized from trimethylsilylacetylene and 4-iodo(methylbenzoate) using a Sonogashira cross-coupling-type reaction as detailed in (Fasina et al., 2005). Recrystallization from hexane afforded crystals of the title compound.

¹H and ¹³C NMR spectra were recorded as an additional method of characterization, ¹H NMR (CDCl₃, 400 MHz): δ = 0.22 (9H, s, SiCH₃), 3.89 (3H, s, CO₂CH₃), 7.49–7.53 (2H, m, ArH), 7.95–7.99 (2H, m, ArH); ¹³C-NMR (CDCl₃, 75.5 MHz): δ = -0.44 (SiCH₃), 52.063 (OCH₃), 97.738 (CC), 104.16 (CC), 127.952 (ArH), 129.53 (ArH), 129.896 (ArH), 132.029 (ArH), 166.761 (CO)

S3. Refinement

Hydrogen atoms were refined in calculated positions, using a riding model (C–H = 0.98–0.99 Å, U_iso(H) = 1.5U_eq(C) for methyl C or 1.2U_eq(C) or the remaining C atoms).

Computing details

Data collection: SMART (Bruker, 2002); cell refinement: SAINT (Bruker, 2003); data reduction: SAINT (Bruker, 2003); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001; Atwood & Barbour, 2003); software used to prepare material for publication: publCIF (Westrip, 2008).

Figures

	Fig. 1. The molecular structure of the title compound showing the atom-labelling scheme. Displacement ellipsoids are shown at the 50% probability level.
	Fig. 2. Herring-bone arrangement of the molecules, viewed down the c axis.
	Fig. 3. C—H···O hydrogen bonds formed between a methyl hydrogen of the trimethylsilyl group and a neighbouring carbonyl oxygen atom. Hydrogen bonds are shown as dashed lines.

Methyl 4-(trimethylsilylethynyl)benzoate

Crystal data

C13H16O2Si	F(000) = 496
Mr = 232.35	Dx = 1.184 Mg m^−3
Orthorhombic, P212121	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P2ac2ab	Cell parameters from 1456 reflections
a = 6.1983 (11) Å	θ = 2.8–23.3°
b = 7.1194 (12) Å	µ = 0.16 mm^−1
c = 29.530 (5) Å	T = 100 K
V = 1303.1 (4) Å^3	Plate, colourless
Z = 4	0.25 × 0.24 × 0.08 mm

Data collection

Bruker APEX CCD area-detector diffractometer	3050 independent reflections
Radiation source: fine-focus sealed tube	2643 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.054
/w scans	θmax = 28.3°, θmin = 2.8°
Absorption correction: multi-scan (SADABS; Bruker, 2002)	h = −7→8
Tmin = 0.960, Tmax = 0.987	k = −8→9
8160 measured reflections	l = −37→32

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)] = 0.058	H-atom parameters constrained
wR(F^2) = 0.114	w = 1/[σ^2(Fo^2) + (0.0431P)^2 + 0.2577P] where P = (Fo^2 + 2Fc^2)/3
S = 1.10	(Δ/σ)max < 0.001
3050 reflections	Δρmax = 0.37 e Å^−3
149 parameters	Δρmin = −0.30 e Å^−3
0 restraints	Absolute structure: Flack (1983), 1136 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: −0.01 (19)

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
Si1	0.68188 (11)	0.55394 (11)	0.42983 (2)	0.01481 (17)
O1	0.1541 (3)	0.5852 (3)	0.12946 (6)	0.0236 (5)
O2	−0.1514 (3)	0.4974 (3)	0.16417 (6)	0.0182 (4)
C1	0.1563 (4)	0.5421 (4)	0.20957 (8)	0.0138 (5)
C2	0.3623 (4)	0.6175 (4)	0.21449 (9)	0.0138 (5)
H2	0.4368	0.6646	0.1888	0.017*
C3	0.4582 (4)	0.6241 (4)	0.25659 (9)	0.0146 (5)
H3	0.5981	0.6770	0.2598	0.017*
C4	0.3507 (4)	0.5533 (4)	0.29466 (8)	0.0133 (5)
C5	0.1428 (4)	0.4787 (4)	0.28942 (8)	0.0137 (5)
H5	0.0673	0.4322	0.3151	0.016*
C6	0.0467 (4)	0.4724 (3)	0.24702 (8)	0.0138 (5)
H6	−0.0936	0.4206	0.2436	0.017*
C7	0.0588 (4)	0.5439 (4)	0.16347 (8)	0.0145 (5)
C8	−0.2620 (4)	0.5084 (4)	0.12112 (9)	0.0220 (7)
H8A	−0.2696	0.6397	0.1113	0.033*
H8B	−0.4084	0.4581	0.1244	0.033*
H8C	−0.1831	0.4347	0.0985	0.033*
C9	0.4551 (4)	0.5535 (4)	0.33826 (8)	0.0149 (5)
C10	0.5448 (4)	0.5509 (4)	0.37428 (8)	0.0169 (5)
C11	0.9744 (4)	0.5113 (5)	0.42078 (10)	0.0299 (8)
H11A	0.9953	0.3856	0.4080	0.045*
H11B	1.0505	0.5202	0.4498	0.045*
H11C	1.0318	0.6055	0.3998	0.045*
C12	0.6371 (5)	0.7888 (4)	0.45560 (9)	0.0219 (6)
H12A	0.6989	0.8858	0.4360	0.033*
H12B	0.7068	0.7937	0.4854	0.033*
H12C	0.4819	0.8108	0.4591	0.033*
C13	0.5661 (5)	0.3652 (4)	0.46578 (10)	0.0272 (7)
H13A	0.4092	0.3806	0.4676	0.041*
H13B	0.6281	0.3728	0.4962	0.041*
H13C	0.5999	0.2426	0.4525	0.041*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Si1	0.0106 (3)	0.0178 (4)	0.0160 (3)	0.0025 (3)	−0.0022 (3)	−0.0019 (3)
O1	0.0155 (9)	0.0366 (12)	0.0188 (10)	−0.0016 (10)	0.0001 (8)	0.0049 (9)
O2	0.0108 (9)	0.0249 (11)	0.0189 (9)	−0.0047 (8)	−0.0051 (7)	0.0009 (7)
C1	0.0119 (11)	0.0130 (13)	0.0166 (12)	0.0010 (12)	−0.0024 (9)	−0.0018 (11)
C2	0.0115 (12)	0.0129 (13)	0.0171 (14)	0.0011 (10)	0.0019 (10)	0.0008 (10)
C3	0.0085 (12)	0.0145 (13)	0.0208 (14)	−0.0016 (10)	−0.0010 (10)	−0.0032 (11)
C4	0.0119 (11)	0.0115 (12)	0.0164 (12)	0.0039 (12)	−0.0024 (9)	−0.0016 (11)
C5	0.0127 (12)	0.0123 (13)	0.0162 (12)	−0.0025 (11)	0.0024 (9)	0.0015 (10)
C6	0.0115 (12)	0.0086 (13)	0.0213 (13)	0.0009 (10)	0.0001 (10)	−0.0019 (11)
C7	0.0124 (11)	0.0110 (12)	0.0199 (13)	0.0007 (11)	−0.0024 (10)	0.0001 (12)
C8	0.0181 (14)	0.0266 (17)	0.0212 (14)	−0.0029 (11)	−0.0079 (11)	−0.0028 (12)
C9	0.0134 (11)	0.0112 (12)	0.0202 (13)	−0.0005 (12)	−0.0010 (10)	−0.0013 (12)
C10	0.0122 (12)	0.0167 (14)	0.0218 (14)	−0.0009 (12)	0.0016 (10)	−0.0021 (12)
C11	0.0186 (14)	0.0392 (19)	0.0320 (18)	0.0086 (13)	−0.0050 (12)	−0.0188 (14)
C12	0.0231 (16)	0.0255 (16)	0.0171 (15)	0.0053 (12)	−0.0037 (12)	−0.0011 (12)
C13	0.0223 (16)	0.0280 (17)	0.0313 (18)	0.0039 (13)	−0.0063 (13)	0.0061 (14)

Geometric parameters (Å, º)

Si1—C10	1.848 (3)	C5—H5	0.9500
Si1—C13	1.857 (3)	C6—H6	0.9500
Si1—C11	1.858 (3)	C8—H8A	0.9800
Si1—C12	1.858 (3)	C8—H8B	0.9800
O1—C7	1.202 (3)	C8—H8C	0.9800
O2—C7	1.344 (3)	C9—C10	1.200 (3)
O2—C8	1.447 (3)	C9—C4	1.441 (3)
C1—C6	1.390 (3)	C11—H11A	0.9800
C1—C2	1.392 (3)	C11—H11B	0.9800
C1—C7	1.490 (3)	C11—H11C	0.9800
C2—H2	0.9500	C12—H12A	0.9800
C3—C2	1.379 (4)	C12—H12B	0.9800
C3—H3	0.9500	C12—H12C	0.9800
C4—C3	1.401 (3)	C13—H13A	0.9800
C4—C5	1.403 (3)	C13—H13B	0.9800
C5—C6	1.387 (3)	C13—H13C	0.9800
C10—Si1—C13	108.75 (14)	O1—C7—O2	123.3 (2)
C10—Si1—C11	108.62 (12)	O1—C7—C1	124.5 (2)
C13—Si1—C11	109.95 (15)	O2—C7—C1	112.2 (2)
C10—Si1—C12	107.78 (13)	Si1—C11—H11A	109.5
C13—Si1—C12	111.06 (14)	Si1—C11—H11B	109.5
C11—Si1—C12	110.61 (14)	H11A—C11—H11B	109.5
C7—O2—C8	115.63 (19)	Si1—C11—H11C	109.5
C10—C9—C4	178.7 (3)	H11A—C11—H11C	109.5
C3—C4—C5	119.0 (2)	H11B—C11—H11C	109.5
C3—C4—C9	120.2 (2)	O2—C8—H8A	109.5
C5—C4—C9	120.8 (2)	O2—C8—H8B	109.5
C6—C1—C2	120.2 (2)	H8A—C8—H8B	109.5
C6—C1—C7	122.1 (2)	O2—C8—H8C	109.5
C2—C1—C7	117.7 (2)	H8A—C8—H8C	109.5
C2—C3—C4	120.4 (2)	H8B—C8—H8C	109.5
C2—C3—H3	119.8	Si1—C12—H12A	109.5
C4—C3—H3	119.8	Si1—C12—H12B	109.5
C3—C2—C1	120.2 (2)	H12A—C12—H12B	109.5
C3—C2—H2	119.9	Si1—C12—H12C	109.5
C1—C2—H2	119.9	H12A—C12—H12C	109.5
C9—C10—Si1	178.4 (3)	H12B—C12—H12C	109.5
C6—C5—C4	120.4 (2)	Si1—C13—H13A	109.5
C6—C5—H5	119.8	Si1—C13—H13B	109.5
C4—C5—H5	119.8	H13A—C13—H13B	109.5
C5—C6—C1	119.8 (2)	Si1—C13—H13C	109.5
C5—C6—H6	120.1	H13A—C13—H13C	109.5
C1—C6—H6	120.1	H13B—C13—H13C	109.5
C5—C4—C3—C2	−1.1 (4)	C2—C1—C6—C5	0.2 (4)
C9—C4—C3—C2	177.5 (2)	C7—C1—C6—C5	−178.3 (2)
C4—C3—C2—C1	0.7 (4)	C8—O2—C7—O1	−2.8 (4)
C6—C1—C2—C3	−0.2 (4)	C8—O2—C7—C1	175.9 (2)
C7—C1—C2—C3	178.3 (2)	C6—C1—C7—O1	−172.3 (3)
C3—C4—C5—C6	1.1 (4)	C2—C1—C7—O1	9.2 (4)
C9—C4—C5—C6	−177.5 (2)	C6—C1—C7—O2	9.0 (4)
C4—C5—C6—C1	−0.6 (4)	C2—C1—C7—O2	−169.5 (2)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C11—H11A···O1^i	0.98	2.58	3.470 (4)	151
C12—H12A···O1^ii	0.98	2.57	3.527 (3)	167

Symmetry codes: (i) −x+1, y−1/2, −z+1/2; (ii) −x+1, y+1/2, −z+1/2.