1-(Phenyl­ethynyl)­adamantane

The title compound, C₁₈H₂₀, provides the first structurally characterized example of an alkynyl-substituted adamantane free from cocrystallized solvent or guest mol­ecules.

Key indicators

• Single-crystal X-ray study
• T = 296 K
• Mean [sigma](C-C) = 0.006 Å
• R factor = 0.057
• wR factor = 0.194
• Data-to-parameter ratio = 14.5

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


 Alert Level C:



PLAT_371  Alert C Long   C(sp2)-C(sp1) Bond  C(12)  -   C(13)  =       1.43 Ang.


 0 Alert Level A = Potentially serious problem

 0 Alert Level B = Potential problem

 1 Alert Level C = Please check

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S1. Comment

Due to the increasing number of nano machines (Balzani et al., 2000; Kelly, 2001) and devices (Rukavishnikov et al., 1999) containing acetylene units attached to bulky caged carbocycles, we have been investigating new routes to achieving one-step synthesis of such systems. Recently, we discovered that the title compound, (I), could be obtained, via a novel metal-mediated process, from phenylacetylene and 1-iodoadamantane (Williams & Raine, 2002). It comprises adamantyl and phenyl groups bridged by a single acetylene residue.

Although structurally characterized examples of substituted adamantanes abound (more than 150 examples in the Cambridge Structural Database; Allen, 2002), there is but one molecule where the substituent is an alkyne attached to the bridgehead C atom. This compound, namely the symmetrical dumb-bell-shaped molecule 1,8-bis(1-adamantyl)-1,3,5,7-octatetrayne, (II), has been found to exhibit a number of interesting structural and non-linear optical properties. Significantly, all structures of (II) have been found to include a cocrystallized guest molecule, such as 2-butanone, crocetin dialdehyde, cyclohexanol and trans-β-8'-apocarotenal (Müller et al., 2000). It was found that (II) exhibits a distinctly bowed conformation of its nominally linear tetra-yne moiety, and the cocrystallized guest molecule appears to have an important influence on the observed conformation of its host (II). We were interested in the conformation of the simple analogue (I), which bears the same ethynyladamantyl group and, to this end, we have been successful in crystallizing (I) in a solvent-free form.

Compound (I) comprises adamantyl and phenyl groups bridged by a single acetylene residue. There is little apparent strain in the molecule and the bond lengths (Table 1) are as expected for a compound of its type. The adamantyl (1.50—1.54 Å) and phenyl C—C bond lengths (1.36–1.40 Å) for the aromatic ring are typical. The (adamantyl)—C1—C11—C12 and C11—C12—C13—(phenyl) angles (Table 1) are both close to linear, although the latter exhibits a small deviation therefrom. There are no hydrogen-bonding interactions in hydrocarbon (I). The closest intermolecular contacts are H9B···H18(-x + 1,+y − 1/2,-z + 1/2) (2.44 Å), H2A···H14(x,-y + 1/2,+z + 1/2) (2.53 Å) and H6B···H7A(-x + 1,-y,-z) (2.53 Å).

In conclusion, in the absence of any cocrystallized guest molecule, we have found that the nominally rod-shaped (I) exhibits an effectively distortionless conformation.

S2. Experimental

The synthesis of the title compound will be reported separately (Williams & Raine, 2002). Crystals were obtained by slow evaporation of a petroleum spirit (313–333 K) solution of the compound.

Computing details

Data collection: CAD-4 EXPRESS (Enraf-Nonius, 1994); cell refinement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS86 (Sheldrick, 1985); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures

Fig. 1. ORTEP-3 plot (Farrugia, 1997) of (I), with ellipsoids at the 30% probability level.

(I)

Crystal data

C18H20	F(000) = 512
Mr = 236.34	Dx = 1.157 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 25 reflections
a = 9.050 (1) Å	θ = 9.8–13.9°
b = 14.224 (1) Å	µ = 0.07 mm^−1
c = 11.081 (1) Å	T = 296 K
β = 107.986 (9)°	Prism, colourless
V = 1356.7 (2) Å^3	0.50 × 0.27 × 0.10 mm
Z = 4

Data collection

Enraf-Nonius CAD-4 diffractometer	1381 reflections with I > 2σ(I)
Radiation source: Enraf-Nonius CAD-4	Rint = 0.028
Graphite monochromator	θmax = 25.0°, θmin = 2.4°
ω–2θ scans	h = 0→10
Absorption correction: ψ scan (North et al., 1968)	k = 0→16
Tmin = 0.911, Tmax = 0.991	l = −13→12
2542 measured reflections	3 standard reflections every 120 min
2385 independent reflections	intensity decay: 4%

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)] = 0.057	H-atom parameters constrained
wR(F^2) = 0.194	w = 1/[σ^2(Fo^2) + (0.038P)^2 + 2.0561P] where P = (Fo^2 + 2Fc^2)/3
S = 1.15	(Δ/σ)max < 0.001
2385 reflections	Δρmax = 0.17 e Å^−3
164 parameters	Δρmin = −0.17 e Å^−3
0 restraints	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.023 (3)

Special details

Experimental. Number of psi-scan sets used was 2 Theta correction was applied. Averaged transmission function was used. No Fourier smoothing was applied.

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
C1	0.4831 (4)	0.1407 (3)	0.1793 (3)	0.0426 (9)
C2	0.4019 (4)	0.1943 (3)	0.2620 (4)	0.0508 (10)
H2A	0.476	0.2077	0.3444	0.061*
H2B	0.3617	0.2536	0.222	0.061*
C3	0.2694 (5)	0.1348 (3)	0.2781 (4)	0.0548 (11)
H3	0.2182	0.1696	0.3304	0.066*
C4	0.1514 (5)	0.1148 (3)	0.1500 (4)	0.0620 (12)
H4A	0.1104	0.1734	0.1082	0.074*
H4B	0.0657	0.0786	0.1611	0.074*
C5	0.2306 (5)	0.0598 (3)	0.0692 (4)	0.0614 (12)
H5	0.155	0.0462	−0.0136	0.074*
C6	0.3625 (5)	0.1196 (3)	0.0506 (4)	0.0562 (11)
H6A	0.3207	0.1781	0.0088	0.067*
H6B	0.4117	0.0862	−0.0031	0.067*
C7	0.5451 (5)	0.0472 (3)	0.2460 (4)	0.0572 (11)
H7A	0.5966	0.0121	0.1955	0.069*
H7B	0.6205	0.0599	0.328	0.069*
C8	0.4122 (5)	−0.0108 (3)	0.2638 (5)	0.0639 (12)
H8	0.453	−0.0699	0.3066	0.077*
C9	0.2953 (6)	−0.0320 (3)	0.1347 (5)	0.0691 (14)
H9A	0.3456	−0.0669	0.0831	0.083*
H9B	0.2114	−0.0702	0.1454	0.083*
C10	0.3316 (6)	0.0439 (3)	0.3438 (4)	0.0659 (13)
H10A	0.2471	0.0068	0.3554	0.079*
H10B	0.4048	0.0568	0.4267	0.079*
C11	0.6127 (4)	0.1958 (3)	0.1605 (4)	0.0493 (10)
C12	0.7184 (4)	0.2388 (3)	0.1455 (4)	0.0488 (10)
C13	0.8431 (4)	0.2901 (3)	0.1222 (3)	0.0412 (9)
C14	0.8467 (4)	0.3048 (3)	−0.0016 (4)	0.0494 (10)
H14	0.7684	0.2798	−0.0695	0.059*
C15	0.9647 (5)	0.3560 (3)	−0.0246 (4)	0.0558 (12)
H15	0.9648	0.3658	−0.1075	0.067*
C16	1.0815 (5)	0.3926 (3)	0.0743 (4)	0.0573 (12)
H16	1.1606	0.4274	0.0584	0.069*
C17	1.0820 (5)	0.3778 (3)	0.1971 (4)	0.0550 (11)
H17	1.1622	0.4021	0.2642	0.066*
C18	0.9641 (4)	0.3272 (3)	0.2213 (4)	0.0485 (10)
H18	0.9654	0.3177	0.3047	0.058*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0360 (19)	0.049 (2)	0.047 (2)	−0.0009 (17)	0.0188 (17)	−0.0012 (18)
C2	0.049 (2)	0.053 (3)	0.054 (2)	0.002 (2)	0.0200 (19)	−0.005 (2)
C3	0.050 (2)	0.063 (3)	0.061 (3)	0.002 (2)	0.032 (2)	−0.008 (2)
C4	0.042 (2)	0.075 (3)	0.072 (3)	−0.003 (2)	0.022 (2)	0.004 (2)
C5	0.056 (3)	0.074 (3)	0.050 (3)	−0.018 (2)	0.012 (2)	−0.006 (2)
C6	0.055 (2)	0.073 (3)	0.044 (2)	−0.010 (2)	0.0210 (19)	−0.002 (2)
C7	0.055 (3)	0.053 (3)	0.064 (3)	0.010 (2)	0.020 (2)	−0.001 (2)
C8	0.072 (3)	0.046 (3)	0.078 (3)	0.004 (2)	0.028 (3)	0.008 (2)
C9	0.077 (3)	0.055 (3)	0.086 (4)	−0.020 (2)	0.041 (3)	−0.019 (3)
C10	0.077 (3)	0.072 (3)	0.057 (3)	−0.005 (3)	0.031 (2)	0.007 (2)
C11	0.047 (2)	0.055 (3)	0.048 (2)	0.001 (2)	0.0182 (19)	−0.0050 (19)
C12	0.044 (2)	0.053 (3)	0.055 (3)	0.000 (2)	0.0231 (19)	−0.004 (2)
C13	0.0369 (19)	0.045 (2)	0.045 (2)	0.0022 (17)	0.0168 (17)	0.0001 (18)
C14	0.045 (2)	0.059 (3)	0.041 (2)	0.002 (2)	0.0074 (18)	−0.002 (2)
C15	0.059 (3)	0.066 (3)	0.050 (2)	0.000 (2)	0.026 (2)	0.010 (2)
C16	0.055 (3)	0.058 (3)	0.067 (3)	−0.007 (2)	0.031 (2)	0.003 (2)
C17	0.047 (2)	0.057 (3)	0.058 (3)	−0.006 (2)	0.012 (2)	−0.011 (2)
C18	0.050 (2)	0.056 (3)	0.045 (2)	0.002 (2)	0.0205 (19)	−0.0043 (19)

Geometric parameters (Å, º)

C1—C11	1.477 (5)	C8—C9	1.523 (6)
C1—C6	1.534 (5)	C8—C10	1.524 (6)
C1—C7	1.541 (5)	C8—H8	0.9800
C1—C2	1.542 (5)	C9—H9A	0.9700
C2—C3	1.523 (5)	C9—H9B	0.9700
C2—H2A	0.9700	C10—H10A	0.9700
C2—H2B	0.9700	C10—H10B	0.9700
C3—C10	1.506 (6)	C11—C12	1.190 (5)
C3—C4	1.517 (6)	C12—C13	1.433 (5)
C3—H3	0.9800	C13—C18	1.393 (5)
C4—C5	1.524 (6)	C13—C14	1.398 (5)
C4—H4A	0.9700	C14—C15	1.379 (5)
C4—H4B	0.9700	C14—H14	0.9300
C5—C9	1.521 (6)	C15—C16	1.369 (6)
C5—C6	1.530 (6)	C15—H15	0.9300
C5—H5	0.9800	C16—C17	1.376 (6)
C6—H6A	0.9700	C16—H16	0.9300
C6—H6B	0.9700	C17—C18	1.380 (5)
C7—C8	1.521 (6)	C17—H17	0.9300
C7—H7A	0.9700	C18—H18	0.9300
C7—H7B	0.9700
C11—C1—C6	110.0 (3)	C1—C7—H7B	109.6
C11—C1—C7	109.8 (3)	H7A—C7—H7B	108.1
C6—C1—C7	109.0 (3)	C7—C8—C9	109.5 (4)
C11—C1—C2	111.5 (3)	C7—C8—C10	109.8 (4)
C6—C1—C2	108.4 (3)	C9—C8—C10	109.2 (4)
C7—C1—C2	108.1 (3)	C7—C8—H8	109.5
C3—C2—C1	109.4 (3)	C9—C8—H8	109.5
C3—C2—H2A	109.8	C10—C8—H8	109.5
C1—C2—H2A	109.8	C5—C9—C8	109.4 (4)
C3—C2—H2B	109.8	C5—C9—H9A	109.8
C1—C2—H2B	109.8	C8—C9—H9A	109.8
H2A—C2—H2B	108.2	C5—C9—H9B	109.8
C10—C3—C4	110.0 (4)	C8—C9—H9B	109.8
C10—C3—C2	110.1 (3)	H9A—C9—H9B	108.3
C4—C3—C2	110.3 (3)	C3—C10—C8	109.4 (3)
C10—C3—H3	108.8	C3—C10—H10A	109.8
C4—C3—H3	108.8	C8—C10—H10A	109.8
C2—C3—H3	108.8	C3—C10—H10B	109.8
C3—C4—C5	108.8 (3)	C8—C10—H10B	109.8
C3—C4—H4A	109.9	H10A—C10—H10B	108.2
C5—C4—H4A	109.9	C12—C11—C1	179.0 (4)
C3—C4—H4B	109.9	C11—C12—C13	177.8 (5)
C5—C4—H4B	109.9	C18—C13—C14	117.8 (3)
H4A—C4—H4B	108.3	C18—C13—C12	121.5 (3)
C9—C5—C4	110.0 (4)	C14—C13—C12	120.7 (4)
C9—C5—C6	109.9 (4)	C15—C14—C13	120.9 (4)
C4—C5—C6	108.8 (4)	C15—C14—H14	119.6
C9—C5—H5	109.4	C13—C14—H14	119.6
C4—C5—H5	109.4	C16—C15—C14	120.3 (4)
C6—C5—H5	109.4	C16—C15—H15	119.9
C5—C6—C1	110.1 (3)	C14—C15—H15	119.9
C5—C6—H6A	109.6	C15—C16—C17	119.9 (4)
C1—C6—H6A	109.6	C15—C16—H16	120.0
C5—C6—H6B	109.6	C17—C16—H16	120.0
C1—C6—H6B	109.6	C16—C17—C18	120.3 (4)
H6A—C6—H6B	108.1	C16—C17—H17	119.8
C8—C7—C1	110.2 (3)	C18—C17—H17	119.8
C8—C7—H7A	109.6	C17—C18—C13	120.7 (4)
C1—C7—H7A	109.6	C17—C18—H18	119.6
C8—C7—H7B	109.6	C13—C18—H18	119.6