2,9-Di­methyl­phenanthro[2,1-b:6,5-b′]di­thio­phene

Moriguchi, T.; Sasaki, M.; Miyoshi, N.

doi:10.1107/S2414314626007005

organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 11| Part 7| July 2026| x260700

https://doi.org/10.1107/S2414314626007005

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2,9-Dimethylphenanthro[2,1-b:6,5-b′]dithiophene

Tetsuji Moriguchi,^a ^* Misa Sasaki ^a and Noriko Miyoshi ^b

^aDepartment of Material Science, Faculty of Engineering, Kyushu Institute of Technology, 1-1 Sensui-cho, Tobata-ku Kitakyushu, Fukuoka, Japan, and ^bTechnical Support Department, Management Headquarters, Kyushu Institute of Technology, 1-1 Sensui-cho, Tobata-ku, Kitakyushu 804-8550, Japan
^*Correspondence e-mail: [email protected]

Edited by W. T. A. Harrison, University of Aberdeen, United Kingdom (Received 12 June 2026; accepted 6 July 2026; online 28 July 2026)

The title compound, C₂₀H₁₄S₂, was synthesized from a dimethyl-substituted thiophene precursor using an oxidative photocyclization reaction. The molecule has a puckered structure due to steric crowding and the extended structure is consolidated by C—H⋯π interactions between columns of stacked molecules.

Keywords: crystal structure; heteropolycyclic aromatic compounds; C—H⋯π interactions.

CCDC reference: 2570636

Structure description

Polycyclic aromatic hydrocarbons, or π-conjugated materials, are an important class of organic compounds that have brought about significant advancements in the field of organic electronics due to their crucial property of conductivity (Wang et al., 2012 ). Previously, the authors reported on the synthesis of various types of polycyclic aromatic compounds using extended π-conjugated materials and the evaluation of their organic photoelectronic properties (Moriguchi et al., 2016 ). More recently, we also reported on the structural properties and crystal structures of heteropolycyclic aromatic compounds for semiconductor materials using X-ray diffraction analysis (Moriguchi et al., 2017a ; Moriguchi et al., 2017b ; Moriguchi et al., 2018 ).

As part of our ongoing studies in this area, this article describes the synthesis and structure determination of the title compound, C₂₀H₁₄S₂, (I). This compound crystallizes in the non-centrosymmetric space group P2₁2₁2₁, with one molecule in the asymmetric unit (Fig. 1). The shape of the molecule is puckered and the dihedral angle between the terminal thiophene rings (C1–C4/S1 and C16–C19/S2) is 17.26 (9)° (Fig. 3). The dihedral angle between the C4–C9 and C12–C17 aromatic rings is 11.61 (9)°. This molecular distortion may arise due to intramolecular congestion: in particular, the short H3⋯H14 contact of 1.98 (3) Å, which is relieved by the molecular twisting. In the extended structure, the molecules are linked by C—H⋯π interactions (Table 1), and are not oriented as a π–π stacked structure (Figs. 2 and 3).

Table 1
Hydrogen-bond geometry (Å, °)

Define Cg2/3/5

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C1—H1B⋯Cg3ⁱ	1.00 (3)	2.84 (3)	3.714 (3)	147 (2)
C7—H7⋯Cg2ⁱⁱ	0.91 (2)	2.962 (19)	3.767 (2)	148.3 (15)
C10—H10⋯Cg5ⁱⁱ	0.99 (2)	2.960 (19)	3.427 (2)	110.1 (13)
Symmetry codes: (i) ; (ii) $[-x, y+{\script{1\over 2}}, -z+{\script{5\over 2}}]$ .

Figure 1
The molecular structure of (I), with displacement ellipsoids drawn at the 50% probability level.

Figure 3
View of the packing of (I), showing C—H⋯π interactions between adjacent molecules.

Figure 2
Packing diagram of (I), with displacement ellipsoids drawn at the 50% probability level. H atoms have been omitted for clarity.

Synthesis and crystallization

All reagents and solvents were purchased from commercial sources and were used without further purification. The electron impact (EI) mass spectrum (MS) of the compound was obtained on a Jeol JMS-SX102A spectrometer using dichloromethane (DCM) as the solvent. The instrument was operated in positive ion mode over an m/z range.

1,3-Bis[2-(2-metylthiophenyl)ethenyl]benzene (1.0 mmol) was dissolved in 200 ml of benzene in a round-bottomed flask at room temperature. To this, iodine (10 mmol) was added, the mixture was stirred and irradiated with UV light using a high-pressure Hg lump for 14 h, quenched with 1.0 mol l⁻¹ Na₂S₂O₃ solution, allowed to warm to room temperature and extracted twice with AcOEt. The organic layer was washed once with 50 ml water, twice with 50 ml of brine, dried over MgSO₄ and the solvent was removed under reduced pressure. The title compound was obtained using silica gel (Wako gel C-300) column chromatography (200 mg, 63% yield) with CH₂Cl₂ as an eluent. Suitable single crystals of (I) in the form of yellow prisms were obtained at room temperature from a solution of dichloromethane–n-hexane (1/1 v/v). MS(EI): M⁺ 318.

Refinement

Key crystallographic data are listed in Table 2. The H atoms were located in difference maps and their positions were freely refined.

Table 2
Experimental details

Crystal data
Chemical formula	C₂₀H₁₄S₂
M_r	318.47
Crystal system, space group	Orthorhombic, P2₁2₁2₁
Temperature (K)	90
a, b, c (Å)	6.5043 (17), 13.456 (3), 17.082 (4)
V (Å³)	1495.0 (7)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	0.35
Crystal size (mm)	0.45 × 0.10 × 0.10

Data collection
Diffractometer	Bruker SMART APEX CCD
Absorption correction	Multi-scan (SADABS; Bruker, 2009 )
T_min, T_max	0.611, 0.745
No. of measured, independent and observed [I ≥ 2u(I)] reflections	14478, 2666, 2543
R_int	0.037
(sin θ/λ)_max (Å⁻¹)	0.598

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.027, 0.065, 1.08
No. of reflections	2666
No. of parameters	255
H-atom treatment	All H-atom parameters refined
Δρ_max, Δρ_min (e Å⁻³)	0.20, −0.17
Absolute structure	Hooft et al. (2010 )
Absolute structure parameter	−0.03 (3)
Computer programs: APEX2 (Bruker, 2009), SAINT (Bruker, 2009), olex2.solve (Bourhis et al., 2015 ), olex2.refine (Bourhis et al., 2015) and OLEX2 (Dolomanov et al., 2009 ).

Structural data

CCDC reference: 2570636

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2414314626007005/hb4565sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314626007005/hb4565Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2414314626007005/hb4565Isup3.cml

checkCIF report

Computing details top

2,9-Dimethylphenanthro[2,1-b:6,5-b']dithiophene top

Crystal data top

C₂₀H₁₄S₂	D_x = 1.415 Mg m⁻³
M_r = 318.47	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, P2₁2₁2₁	Cell parameters from 6305 reflections
a = 6.5043 (17) Å	θ = 2.4–25.1°
b = 13.456 (3) Å	µ = 0.35 mm⁻¹
c = 17.082 (4) Å	T = 90 K
V = 1495.0 (7) Å³	Prism, clear light yellow
Z = 4	0.45 × 0.10 × 0.10 mm
F(000) = 665.274

Data collection top

Bruker SMART APEX CCD diffractometer	2666 independent reflections
Radiation source: sealed tube	2543 reflections with I ≥ 2u(I)
Graphite monochromator	R_int = 0.037
Detector resolution: 8 pixels mm^-1	θ_max = 25.1°, θ_min = 2.4°
ω scans	h = −7→7
Absorption correction: multi-scan SADABS (Bruker, 2009)	k = −16→16
T_min = 0.611, T_max = 0.745	l = −20→20
14478 measured reflections

Refinement top

Refinement on F²	Primary atom site location: iterative
Least-squares matrix: full	All H-atom parameters refined
R[F² > 2σ(F²)] = 0.027	w = 1/[σ²(F_o²) + (0.0346P)² + 0.2686P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.065	(Δ/σ)_max = 0.001
S = 1.08	Δρ_max = 0.20 e Å⁻³
2666 reflections	Δρ_min = −0.17 e Å⁻³
255 parameters	Absolute structure: Hooft et al. (2010)
0 restraints	Absolute structure parameter: −0.03 (3)
0 constraints

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
S1	−0.04847 (9)	0.63225 (4)	1.13345 (3)	0.02673 (13)
S2	0.15028 (9)	0.18292 (4)	0.70895 (3)	0.02671 (13)
C1	−0.3530 (4)	0.68925 (17)	1.02692 (15)	0.0332 (5)
H1a	−0.377 (4)	0.701 (2)	0.9739 (18)	0.062 (9)*
H1b	−0.484 (5)	0.660 (2)	1.0463 (16)	0.067 (9)*
H1c	−0.336 (5)	0.751 (2)	1.0483 (16)	0.068 (9)*
C20	0.4911 (4)	0.05841 (19)	0.68237 (14)	0.0383 (6)
H20a	0.628 (5)	0.047 (2)	0.6963 (16)	0.055 (8)*
H20b	0.424 (5)	−0.007 (2)	0.6861 (16)	0.066 (9)*
H20c	0.484 (4)	0.0714 (19)	0.6294 (16)	0.055 (8)*
C2	−0.1704 (3)	0.62557 (14)	1.04301 (11)	0.0245 (4)
C3	−0.0746 (3)	0.56109 (13)	0.99428 (11)	0.0214 (4)
H3	−0.121 (3)	0.5547 (14)	0.9429 (11)	0.018 (5)*
C4	0.1031 (3)	0.51287 (13)	1.02696 (10)	0.0193 (4)
C5	0.1397 (3)	0.54895 (13)	1.10359 (11)	0.0224 (4)
C19	0.3958 (3)	0.13846 (14)	0.73123 (11)	0.0264 (5)
C18	0.4745 (3)	0.18496 (14)	0.79448 (11)	0.0240 (4)
H18	0.598 (3)	0.1690 (15)	0.8135 (11)	0.020 (5)*
C17	0.3420 (3)	0.25900 (13)	0.82838 (10)	0.0201 (4)
C16	0.1569 (3)	0.26534 (13)	0.78785 (10)	0.0215 (4)
C6	0.3123 (3)	0.52437 (14)	1.14820 (11)	0.0252 (4)
H6	0.332 (3)	0.5511 (15)	1.2015 (13)	0.030 (6)*
C7	0.4554 (4)	0.46387 (14)	1.11539 (11)	0.0237 (4)
H7	0.572 (3)	0.4467 (14)	1.1416 (11)	0.015 (5)*
C15	−0.0010 (3)	0.32809 (14)	0.81307 (11)	0.0225 (4)
H15	−0.128 (4)	0.3298 (15)	0.7842 (12)	0.031 (6)*
C14	0.0304 (3)	0.38536 (13)	0.87894 (11)	0.0208 (4)
H14	−0.086 (3)	0.4230 (13)	0.8932 (10)	0.013 (5)*
C10	0.5811 (3)	0.35708 (14)	1.00967 (11)	0.0227 (4)
H10	0.710 (3)	0.3506 (14)	1.0398 (11)	0.025 (6)*
C11	0.5574 (3)	0.30801 (14)	0.94137 (11)	0.0222 (4)
H11	0.655 (3)	0.2674 (15)	0.9225 (11)	0.023 (5)*
C9	0.2457 (3)	0.44063 (12)	0.99489 (11)	0.0176 (4)
C13	0.2158 (3)	0.38424 (13)	0.92283 (10)	0.0176 (4)
C8	0.4253 (3)	0.42170 (13)	1.03969 (10)	0.0205 (4)
C12	0.3746 (3)	0.31869 (13)	0.89681 (10)	0.0184 (4)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
S1	0.0315 (3)	0.0248 (2)	0.0239 (2)	0.0001 (2)	0.0038 (2)	−0.0052 (2)
S2	0.0352 (3)	0.0251 (2)	0.0199 (2)	0.0027 (2)	−0.0002 (2)	−0.0034 (2)
C1	0.0330 (13)	0.0281 (11)	0.0384 (13)	0.0082 (11)	0.0022 (11)	−0.0012 (10)
C20	0.0516 (18)	0.0365 (13)	0.0269 (12)	0.0172 (12)	−0.0013 (11)	−0.0066 (10)
C2	0.0261 (10)	0.0200 (9)	0.0275 (10)	−0.0017 (9)	0.0033 (9)	0.0010 (8)
C3	0.0258 (11)	0.0176 (9)	0.0207 (10)	−0.0041 (8)	−0.0023 (9)	0.0013 (8)
C4	0.0228 (11)	0.0155 (9)	0.0197 (9)	−0.0051 (7)	0.0022 (7)	0.0025 (7)
C5	0.0262 (11)	0.0187 (9)	0.0223 (9)	−0.0043 (8)	0.0045 (9)	−0.0002 (7)
C19	0.0369 (13)	0.0197 (9)	0.0226 (9)	0.0063 (9)	0.0025 (9)	0.0033 (8)
C18	0.0275 (11)	0.0198 (9)	0.0248 (9)	0.0054 (9)	0.0011 (9)	0.0054 (9)
C17	0.0263 (10)	0.0153 (8)	0.0187 (8)	−0.0001 (8)	0.0063 (9)	0.0047 (7)
C16	0.0290 (10)	0.0186 (9)	0.0169 (8)	−0.0026 (8)	0.0018 (9)	0.0003 (7)
C6	0.0322 (12)	0.0233 (9)	0.0202 (10)	−0.0066 (9)	−0.0022 (9)	−0.0002 (8)
C7	0.0239 (10)	0.0220 (10)	0.0251 (10)	−0.0033 (9)	−0.0076 (9)	0.0060 (8)
C15	0.0191 (11)	0.0265 (10)	0.0218 (9)	−0.0018 (8)	−0.0012 (8)	−0.0004 (8)
C14	0.0195 (9)	0.0200 (9)	0.0229 (9)	0.0014 (8)	0.0013 (8)	−0.0007 (8)
C10	0.0210 (11)	0.0200 (9)	0.0271 (10)	0.0006 (8)	−0.0028 (9)	0.0068 (8)
C11	0.0219 (10)	0.0161 (9)	0.0286 (10)	0.0012 (9)	0.0026 (9)	0.0038 (8)
C9	0.0183 (9)	0.0133 (8)	0.0212 (9)	−0.0028 (7)	0.0020 (8)	0.0049 (7)
C13	0.0198 (10)	0.0147 (9)	0.0184 (9)	−0.0024 (7)	0.0027 (7)	0.0049 (7)
C8	0.0241 (11)	0.0146 (9)	0.0227 (9)	−0.0025 (8)	−0.0001 (8)	0.0060 (7)
C12	0.0192 (9)	0.0156 (8)	0.0205 (8)	−0.0015 (8)	0.0030 (8)	0.0061 (8)

Geometric parameters (Å, º) top

S1—C2	1.739 (2)	C18—C17	1.439 (3)
S1—C5	1.736 (2)	C17—C16	1.392 (3)
S2—C19	1.747 (2)	C17—C12	1.434 (2)
S2—C16	1.7459 (18)	C16—C15	1.397 (3)
C1—H1a	0.93 (3)	C6—H6	0.99 (2)
C1—H1b	1.00 (3)	C6—C7	1.358 (3)
C1—H1c	0.92 (3)	C7—H7	0.91 (2)
C1—C2	1.490 (3)	C7—C8	1.426 (3)
C20—H20a	0.94 (3)	C15—H15	0.96 (2)
C20—H20b	0.99 (3)	C15—C14	1.379 (3)
C20—H20c	0.92 (3)	C14—H14	0.941 (19)
C20—C19	1.497 (3)	C14—C13	1.420 (3)
C2—C3	1.354 (3)	C10—H10	0.99 (2)
C3—H3	0.931 (19)	C10—C11	1.349 (3)
C3—C4	1.438 (3)	C10—C8	1.431 (3)
C4—C5	1.416 (3)	C11—H11	0.90 (2)
C4—C9	1.451 (3)	C11—C12	1.419 (3)
C5—C6	1.396 (3)	C9—C13	1.459 (3)
C19—C18	1.349 (3)	C9—C8	1.419 (3)
C18—H18	0.89 (2)	C13—C12	1.429 (2)

C5—S1—C2	91.55 (10)	C12—C17—C16	119.94 (17)
C16—S2—C19	91.54 (9)	C17—C16—S2	111.49 (14)
H1b—C1—H1a	105 (2)	C15—C16—S2	127.14 (16)
H1c—C1—H1a	104 (2)	C15—C16—C17	121.29 (17)
H1c—C1—H1b	109 (2)	H6—C6—C5	121.4 (13)
C2—C1—H1a	114.3 (17)	C7—C6—C5	117.89 (18)
C2—C1—H1b	112.8 (16)	C7—C6—H6	120.7 (13)
C2—C1—H1c	111 (2)	H7—C7—C6	121.3 (12)
H20b—C20—H20a	105 (2)	C8—C7—C6	121.2 (2)
H20c—C20—H20a	109 (2)	C8—C7—H7	117.4 (12)
H20c—C20—H20b	102 (2)	H15—C15—C16	119.1 (12)
C19—C20—H20a	111.5 (17)	C14—C15—C16	118.73 (18)
C19—C20—H20b	115.3 (17)	C14—C15—H15	122.1 (12)
C19—C20—H20c	113.0 (16)	H14—C14—C15	113.2 (11)
C1—C2—S1	119.84 (15)	C13—C14—C15	123.40 (18)
C3—C2—S1	111.69 (15)	C13—C14—H14	123.3 (11)
C3—C2—C1	128.44 (19)	C11—C10—H10	120.3 (11)
H3—C3—C2	119.4 (12)	C8—C10—H10	117.9 (11)
C4—C3—C2	114.84 (17)	C8—C10—C11	121.75 (19)
C4—C3—H3	125.6 (12)	H11—C11—C10	121.9 (13)
C5—C4—C3	109.83 (17)	C12—C11—C10	120.67 (19)
C9—C4—C3	132.02 (16)	C12—C11—H11	117.5 (13)
C9—C4—C5	118.10 (17)	C13—C9—C4	125.57 (17)
C4—C5—S1	111.97 (15)	C8—C9—C4	116.27 (16)
C6—C5—S1	124.00 (14)	C8—C9—C13	118.12 (16)
C6—C5—C4	123.95 (18)	C9—C13—C14	123.58 (17)
C20—C19—S2	120.21 (17)	C12—C13—C14	117.14 (16)
C18—C19—S2	111.24 (15)	C12—C13—C9	119.14 (16)
C18—C19—C20	128.6 (2)	C10—C8—C7	118.00 (18)
H18—C18—C19	121.4 (13)	C9—C8—C7	122.06 (18)
C17—C18—C19	114.60 (19)	C9—C8—C10	119.93 (17)
C17—C18—H18	124.0 (13)	C11—C12—C17	120.30 (17)
C16—C17—C18	111.12 (17)	C13—C12—C17	119.49 (17)
C12—C17—C18	128.86 (19)	C13—C12—C11	120.08 (16)

S1—C2—C3—C4	0.09 (16)	C19—C18—C17—C16	0.72 (19)
S1—C5—C4—C3	3.52 (15)	C19—C18—C17—C12	177.42 (15)
S1—C5—C4—C9	−178.57 (12)	C18—C17—C16—C15	176.11 (15)
S1—C5—C6—C7	−175.12 (16)	C18—C17—C12—C11	−0.5 (2)
S2—C19—C18—C17	−0.14 (16)	C18—C17—C12—C13	−176.35 (18)
S2—C16—C17—C18	−0.96 (15)	C17—C16—C15—C14	0.8 (2)
S2—C16—C17—C12	−177.99 (11)	C17—C12—C11—C10	−173.85 (17)
S2—C16—C15—C14	177.40 (16)	C17—C12—C13—C14	0.78 (18)
C1—C2—C3—C4	178.1 (2)	C17—C12—C13—C9	176.65 (15)
C20—C19—C18—C17	−179.9 (2)	C16—C15—C14—C13	0.1 (2)
C2—C3—C4—C5	−2.33 (19)	C6—C7—C8—C10	−178.76 (18)
C2—C3—C4—C9	−179.85 (15)	C6—C7—C8—C9	0.1 (2)
C3—C4—C5—C6	−173.39 (14)	C7—C8—C10—C11	174.71 (17)
C3—C4—C9—C13	−12.7 (2)	C7—C8—C9—C13	−172.10 (16)
C3—C4—C9—C8	169.6 (2)	C15—C14—C13—C9	−176.58 (17)
C4—C5—C6—C7	1.4 (2)	C15—C14—C13—C12	−0.9 (2)
C4—C9—C13—C14	−7.2 (2)	C14—C13—C9—C8	170.49 (17)
C4—C9—C13—C12	177.26 (17)	C14—C13—C12—C11	−175.03 (16)
C4—C9—C8—C7	5.76 (19)	C10—C11—C12—C13	1.9 (2)
C4—C9—C8—C10	−175.41 (15)	C10—C8—C9—C13	6.72 (19)
C5—C6—C7—C8	−3.8 (2)	C11—C12—C13—C9	0.84 (19)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1B···Cg3ⁱ	1.00 (3)	2.84 (3)	3.714 (3)	147 (2)
C7—H7···Cg2ⁱⁱ	0.91 (2)	2.962 (19)	3.767 (2)	148.3 (15)
C10—H10···Cg5ⁱⁱ	0.99 (2)	2.960 (19)	3.427 (2)	110.1 (13)

Symmetry codes: (i) x−1, y, z; (ii) −x, y+1/2, −z+5/2.

Acknowledgements

We are grateful to the Center for Instrumental Analysis, Kyushu Institute of Technology (KITCIA), for the X-ray analysis.

References

Bourhis, L. J., Dolomanov, O. V., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2015). Acta Cryst. A71, 59–75. Web of Science CrossRef IUCr Journals Google Scholar
Bruker (2009). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339–341. Web of Science CrossRef CAS IUCr Journals Google Scholar
Hooft, R. W. W., Straver, L. H. & Spek, A. L. (2010). J. Appl. Cryst. 43, 665–668. Web of Science CrossRef CAS IUCr Journals Google Scholar
Moriguchi, T., Higashi, M., Yakeya, D., Jalli, V., Tsuge, A., Okauchi, T., Nagamatsu, S. & Takashima, W. (2017a). J. Mol. Struct. 1127, 413–418. CrossRef Google Scholar
Moriguchi, T., Mitsumoto, K., Nishizawa, Y., Yakeya, D., Jalli, V. & Tsuge, A. (2016). Cryst. Struct. Theory Appl. 5, 63–73. Google Scholar
Moriguchi, T., Tabuchi, D., Yakeya, D., Tsuge, A. & Jalli, V. (2017b). Crystals 7, 251. CrossRef Google Scholar
Moriguchi, T., Tabuchi, D., Yakeya, D., Tsuge, A., Jalli, V. & Yoza, K. (2018). J. Mol. Struct. 1152, 37–43. CrossRef Google Scholar
Wang, C., Dong, H., Hu, W., Liu, Y. & Zhu, D. (2012). Chem. Rev. 112, 2208–2267. Web of Science CrossRef CAS PubMed Google Scholar

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