1-Iodo­triptycene

Abstract

The title compound, C₂₀H₁₃I, is a halogenated derivative of triptycene. The mol­ecule shows crystallographic as well as non-crystallographic C ₃ symmetry. The asymmetric unit comprises one third of the mol­ecule. Dispersive I⋯I contacts [I⋯I = 3.6389 (3) Å] connect the mol­ecules into dimers. The shortest centroid–centroid distance between two π-systems is 3.8403 (12) Å.

Related literature

For the crystal structures of 1-bromo­triptycene, 9,10-di­bromo­triptycene and 10-bromo-9-triptycyl iodo­formate, see: Palmer & Templeton (1968 ▶), Abergel & Dinca (2004 ▶) and de Wet et al. (1978 ▶), respectively. For the preparation, see: Bartel et al. (1971 ▶).

Experimental

Crystal data

• C₂₀H₁₃I

• M _r = 380.20

• Hexagonal,

• a = 11.8820 (4) Å

• c = 17.6800 (5) Å

• V = 2161.68 (12) ų

• Z = 6

• Mo Kα radiation

• μ = 2.21 mm⁻¹

• T = 200 K

• 0.56 × 0.51 × 0.25 mm

Data collection

• Bruker APEXII CCD diffractometer

• Absorption correction: multi-scan (SADABS; Bruker, 2008 ▶) T _min = 0.568, T _max = 0.746

• 4033 measured reflections

• 1184 independent reflections

• 1156 reflections with I > 2σ(I)

• R _int = 0.011

Refinement

• R[F ² > 2σ(F ²)] = 0.021

• wR(F ²) = 0.059

• S = 1.15

• 1184 reflections

• 64 parameters

• H-atom parameters constrained

• Δρ_max = 1.52 e Å⁻³

• Δρ_min = −0.51 e Å⁻³

Data collection: APEX2 (Bruker, 2010 ▶); cell refinement: SAINT (Bruker, 2010 ▶); data reduction: SAINT; program(s) used to solve structure: SIR97 (Altomare et al., 1999 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009 ▶).

Supplementary Material

Supplementary material file. DOI: 10.1107/S160053681103279X/nk2107Isup2.cdx

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

supplementary crystallographic information

Comment

The chemistry of molecules featuring double and triple bonds involving elements from the third row of the periodic system of the elements (or below) is affected by the marked tendency of oligo- and polymerization. The introduction of sterically demanding, "bulky" protective groups in proximity to such bonding systems allowed the isolation and characterization of respective compounds on grounds of steric shielding and, as a consequence, markedly decreased rate of polymerization. It seemed of interest for us to study whether the presence of such aforementioned bonding systems has an influence on the metrical parameters of the applied protection groups as well. Therefore, we determined the crystal structure of the title compound. So far, the molecular and crystal stuctures of 1-bromotriptycene (Palmer & Templeton, 1968), 9,10-dibromotriptycene (Abergel & Dinca, 2004) as well as 10-bromo-9-triptycyl iodoformate (de Wet et al., 1978) are the only examples of structurally characterized triptycene compounds bearing a halogenido substituent on the bridgehead carbon atom present in the literature.

Halogenation took place on one of the bridgehead carbon atoms of the triptycene molecule (Figure 1). The least-squares planes defined by the atoms of the three aromatic moieties enclose angles of 60.03 (4) ° and 60.03 (7), respectively.

In the molecules, dispersive I···I contacts whose range falls by more than 0.3 Å below the sum of van der Waals radii can be observed (Figure 2). These connect two molecules to dimeric units whose I···I vector is pointing along the crystallographic c axis. The aromatic moieties of one molecule in such a dimer adopt a staggered conformation towards the aromatic moieties in the other molecule when projected along the I···I axis. The closest intercentroid distance between two π-systems was measured at 3.8403 (12) Å.

Experimental

The compound was formed through the thermolysis of 9-triptycyl iodoformate according to a published procedure (Bartel et al., 1971).

Refinement

Carbon-bound H atoms were placed in calculated positions (C—H 0.95 Å for aromatic carbon atoms, C—H 1.00 Å for the bridgehead carbon atom) and were included in the refinement in the riding model approximation, with U(H) set to 1.2U_eq(C).

Figures

Fig. 1.

The molecular structure of the title compound, anisotropic displacement ellipsoids are drawn at 50% probability level. Symmetry operators: i -y, x-y, z; ii -x + y, -x, z.

Fig. 2.

Intermolecular I···I contact, viewed along [0 - 1 0]. Symmetry operator: i -x, -y, -z.

Crystal data

C20H13I	Dx = 1.752 Mg m−3
Mr = 380.20	Mo Kα radiation, λ = 0.71069 Å
Hexagonal, R3	Cell parameters from 3561 reflections
Hall symbol: -R 3	θ = 4.1–28.3°
a = 11.8820 (4) Å	µ = 2.21 mm−1
c = 17.6800 (5) Å	T = 200 K
V = 2161.68 (12) Å3	Block, colourless
Z = 6	0.56 × 0.51 × 0.25 mm
F(000) = 1116

Data collection

Bruker APEXII CCD diffractometer	1184 independent reflections
Radiation source: fine-focus sealed tube	1156 reflections with I > 2σ(I)
graphite	Rint = 0.011
φ and ω scans	θmax = 28.3°, θmin = 3.5°
Absorption correction: multi-scan (SADABS; Bruker, 2008)	h = −15→10
Tmin = 0.568, Tmax = 0.746	k = −13→15
4033 measured reflections	l = −20→23

Refinement

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.021	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.059	H-atom parameters constrained
S = 1.15	w = 1/[σ2(Fo2) + (0.0366P)2 + 2.801P] where P = (Fo2 + 2Fc2)/3
1184 reflections	(Δ/σ)max < 0.001
64 parameters	Δρmax = 1.52 e Å−3
0 restraints	Δρmin = −0.51 e Å−3

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

	x	y	z	Uiso*/Ueq
I1	0.0000	0.0000	0.102907 (11)	0.03354 (10)
C1	0.11904 (15)	0.11668 (15)	0.33674 (10)	0.0219 (3)
C2	0.12090 (15)	0.11714 (15)	0.25794 (10)	0.0207 (3)
C3	0.22522 (17)	0.21626 (17)	0.21950 (11)	0.0264 (3)
H3	0.2274	0.2169	0.1658	0.032*
C4	0.32674 (18)	0.31494 (17)	0.26061 (13)	0.0330 (4)
H4	0.3988	0.3826	0.2346	0.040*
C5	0.32397 (18)	0.31565 (18)	0.33846 (14)	0.0337 (4)
H5	0.3933	0.3842	0.3657	0.040*
C6	0.21961 (18)	0.21594 (17)	0.37755 (12)	0.0284 (4)
H6	0.2174	0.2160	0.4313	0.034*
C7	0.0000	0.0000	0.22412 (15)	0.0188 (5)
C8	0.0000	0.0000	0.37075 (17)	0.0224 (5)
H8	0.0000	0.0000	0.4273	0.027*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
I1	0.04045 (12)	0.04045 (12)	0.01971 (13)	0.02022 (6)	0.000	0.000
C1	0.0206 (7)	0.0206 (7)	0.0262 (8)	0.0115 (6)	−0.0022 (6)	−0.0016 (6)
C2	0.0177 (7)	0.0176 (7)	0.0276 (8)	0.0094 (6)	−0.0006 (6)	−0.0004 (6)
C3	0.0230 (7)	0.0231 (7)	0.0318 (9)	0.0107 (6)	0.0039 (6)	0.0044 (6)
C4	0.0212 (8)	0.0203 (8)	0.0530 (12)	0.0071 (6)	0.0005 (7)	0.0042 (8)
C5	0.0238 (8)	0.0206 (7)	0.0538 (12)	0.0089 (7)	−0.0117 (8)	−0.0056 (8)
C6	0.0280 (8)	0.0254 (8)	0.0349 (9)	0.0157 (7)	−0.0098 (7)	−0.0072 (7)
C7	0.0202 (7)	0.0202 (7)	0.0162 (12)	0.0101 (4)	0.000	0.000
C8	0.0242 (8)	0.0242 (8)	0.0189 (13)	0.0121 (4)	0.000	0.000

Geometric parameters (Å, °)

I1—C7	2.143 (3)	C4—H4	0.9500
C1—C6	1.389 (2)	C5—C6	1.396 (3)
C1—C2	1.393 (2)	C5—H5	0.9500
C1—C8	1.524 (2)	C6—H6	0.9500
C2—C3	1.388 (2)	C7—C2i	1.5359 (19)
C2—C7	1.5359 (19)	C7—C2ii	1.5359 (19)
C3—C4	1.394 (3)	C8—C1i	1.524 (2)
C3—H3	0.9500	C8—C1ii	1.524 (2)
C4—C5	1.377 (4)	C8—H8	1.0000
C6—C1—C2	120.71 (16)	C1—C6—C5	119.03 (19)
C6—C1—C8	125.48 (18)	C1—C6—H6	120.5
C2—C1—C8	113.81 (16)	C5—C6—H6	120.5
C3—C2—C1	119.92 (16)	C2—C7—C2i	105.82 (13)
C3—C2—C7	127.75 (17)	C2—C7—C2ii	105.82 (13)
C1—C2—C7	112.33 (16)	C2i—C7—C2ii	105.82 (13)
C2—C3—C4	119.24 (18)	C2—C7—I1	112.92 (11)
C2—C3—H3	120.4	C2i—C7—I1	112.92 (11)
C4—C3—H3	120.4	C2ii—C7—I1	112.92 (11)
C5—C4—C3	120.87 (17)	C1i—C8—C1ii	105.46 (14)
C5—C4—H4	119.6	C1i—C8—C1	105.46 (14)
C3—C4—H4	119.6	C1ii—C8—C1	105.46 (14)
C4—C5—C6	120.22 (17)	C1i—C8—H8	113.2
C4—C5—H5	119.9	C1ii—C8—H8	113.2
C6—C5—H5	119.9	C1—C8—H8	113.2
C6—C1—C2—C3	1.2 (2)	C3—C2—C7—C2i	122.9 (2)
C8—C1—C2—C3	−178.53 (13)	C1—C2—C7—C2i	−56.63 (15)
C6—C1—C2—C7	−179.19 (13)	C3—C2—C7—C2ii	−125.1 (2)
C8—C1—C2—C7	1.07 (16)	C1—C2—C7—C2ii	55.38 (16)
C1—C2—C3—C4	−0.4 (2)	C3—C2—C7—I1	−1.06 (17)
C7—C2—C3—C4	−179.98 (14)	C1—C2—C7—I1	179.37 (9)
C2—C3—C4—C5	−0.6 (3)	C6—C1—C8—C1i	−124.7 (2)
C3—C4—C5—C6	0.9 (3)	C2—C1—C8—C1i	55.02 (16)
C2—C1—C6—C5	−0.9 (2)	C6—C1—C8—C1ii	124.0 (2)
C8—C1—C6—C5	178.79 (14)	C2—C1—C8—C1ii	−56.30 (16)
C4—C5—C6—C1	−0.1 (3)

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