5,5'-Dimethyl-2,2'-[p-phenyl­ene­bis­(methyl­ene­thio)]­bis(4,5-dihydro­thia­zole)

The title compound, C₁₆H₂₀N₂S₄, contains two terminal 5-methyl-4,5-dihydro­thia­zole rings and a central benzene ring. The mol­ecule lies on an inversion centre. This symmetry imposes a trans configuration for the terminal heterocyclic systems with respect to the central benzene ring. The S-C bond lengths are significantly different, depending on the hybridization state of the C atoms.

Key indicators

• Single-crystal X-ray study
• T = 294 K
• Mean [sigma](C-C) = 0.005 Å
• R factor = 0.050
• wR factor = 0.134
• Data-to-parameter ratio = 15.9

checkCIF/PLATON results

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Alert level B
PLAT230_ALERT_2_B Hirshfeld Test Diff for    N1     -   C4      ..      13.26 su

Alert level C
PLAT241_ALERT_2_C Check High      Ueq as Compared to Neighbors for         S1
PLAT241_ALERT_2_C Check High      Ueq as Compared to Neighbors for         C3
PLAT322_ALERT_2_C Check Hybridisation of  S1     in Main Residue .          ?
PLAT340_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang ...          5

Alert level G
PLAT793_ALERT_1_G Check the Absolute Configuration of C2     = ...          R

   0 ALERT level A = In general: serious problem
   1 ALERT level B = Potentially serious problem
   4 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
   4 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

As a type of ditopic ligand, dithioethers can be used as bridging ligands in the construction of coordination polymers with soft metal ions. A series of flexible or rigid chain-linked dithioethers containing N-heterocylcic moieties have been synthesized and investigated (Sharma et al., 1999; Constable et al., 2002). Early studies reported that several tetrazole and imidazole derivatives possess a variety of coordination properties (van den Heuvel et al., 1983; Yang et al., 2000). In order to study the properties of dihydrothiazole derivatives, we have synthesized the title compound, (I), and present here its molecular structure.

The title compound contains two 5-methyl-4,5-dihydrothiazole rings and a central benzene ring. The whole molecule lies on a crystallographic inversion centre [symmetry code: (i) -x,-y + 1,-z + 1] and the terminal (5-methyl-4,5-dihydrothiazole-2-yl)sulfanyl groups thus adopt a trans configuration with respect to the central benzene ring. In the thiazole ring, the C4 atom of the C═N bond has a distorted trigonal geometry, with the N1—C4—S2 [127.8 (3)°] and N1—C4—S1 [116.0 (3)°] angles deviating significantly from the ideal values expected for an sp² hybridized C atom.

Due to the p–π configuration between the S2 atom and the adjacent C═N bond, the S2—C4 bond, 1.759 (3) Å, is significantly shorter than the S2—C5 bond, 1.822 (4) Å. These values compare well with the values of 1.726 (2), 1.720 (8) and 1.800 (3), 1.811 (2) Å reported in the literature (Wang et al., 2004, 2005). The effect is also observed for S1 in the substituted dihydrothiazole ring.

A closely dithiazole structure, 2,2'-[1,4-phenylenebis(methylenethio)]dithiazole, has been published by Zhang et al. (2003).

Related literature

For related literature, see: Constable et al. (2002); van den Heuvel et al. (1983); Sharma et al. (1999); Wang et al. (2004, 2005); Yang et al. (2000); Zhang et al. (2003).

S2. Experimental

A suspension of 1,4-dibromomethylbenzene (5 mmol) in THF (10 ml) was added dropwise to a mixture of 2-mercapto-5-methyl-4,5-dihydrothiazole (11 mmol), KOH (11 mmol) and ethanol (20 ml). The reaction mixture was then stirred for 24 h at room temperature. The precipitate was filtered off, washed with water and recrystallized from ethanol (yield 65%, m.p. 378–379 K). Crystals of (I) suitable for single-crystal X-ray analysis were grown by slow evaporation of a solution in a mixture of chloroform/ethanol (1:1).

S3. Refinement

All H atoms were positioned geometrically and refined using a riding model approximation, with C—H bonds fixed to 0.93 (aromatic CH), 0.96 (methyl CH₃, considered as a rigid group allowed to rotate) 0.97 (methylene CH₂) or 0.98 Å (methine CH). Isotropic displacement parameters for H atoms were fixed as U_iso = 1.5U_eq(carrier C) for the methyl group and U_iso = 1.5U_eq(carrier C) otherwise.

Computing details

Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); data reduction: SAINT (Bruker, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 1997); software used to prepare material for publication: SHELXTL (Bruker, 1997).

Figures

Fig. 1. View of the molecule of (I) showing the atom-labeling scheme. Displacement ellipsoids are drawn at the 35% probability level. Symmetry code: (A) -x, -y + 1, -z + 1.

5,5'-Dimethyl-2,2'-[p-phenylenebis(methylenethio)]bis(4,5-dihydrothiazole)

Crystal data

C16H20N2S4	F(000) = 388
Mr = 368.62	Dx = 1.345 Mg m^−3
Monoclinic, P21/c	Melting point = 378–379 K
Hall symbol: -P 2ybc	Mo Kα radiation, λ = 0.71073 Å
a = 6.9337 (8) Å	Cell parameters from 1193 reflections
b = 16.133 (2) Å	θ = 2.5–24.1°
c = 8.2475 (10) Å	µ = 0.52 mm^−1
β = 99.519 (6)°	T = 294 K
V = 909.89 (19) Å^3	Plate, colourless
Z = 2	0.24 × 0.20 × 0.18 mm

Data collection

Bruker SMART 1000 diffractometer	1605 independent reflections
Radiation source: fine-focus sealed tube	1155 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.039
φ and ω scans	θmax = 25.0°, θmin = 2.5°
Absorption correction: multi-scan (SADABS; Bruker, 1997)	h = −8→8
Tmin = 0.886, Tmax = 0.912	k = −19→11
3806 measured reflections	l = −9→7

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.050	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.135	H-atom parameters constrained
S = 1.05	w = 1/[σ^2(Fo^2) + (0.0596P)^2 + 0.5874P] where P = (Fo^2 + 2Fc^2)/3
1605 reflections	(Δ/σ)max = 0.001
101 parameters	Δρmax = 0.32 e Å^−3
0 restraints	Δρmin = −0.34 e Å^−3

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

	x	y	z	Uiso*/Ueq
S1	0.45045 (15)	0.88289 (6)	0.58489 (15)	0.0666 (4)
S2	0.25410 (12)	0.71998 (6)	0.49929 (12)	0.0529 (3)
N1	0.6275 (4)	0.74297 (17)	0.6648 (3)	0.0439 (7)
C1	0.8272 (6)	0.9020 (3)	0.5154 (6)	0.0711 (12)
H1A	0.9653	0.9008	0.5552	0.107*
H1B	0.7913	0.9553	0.4683	0.107*
H1C	0.7945	0.8599	0.4331	0.107*
C2	0.7177 (5)	0.8862 (2)	0.6559 (5)	0.0548 (10)
H2	0.7487	0.9298	0.7387	0.066*
C3	0.7621 (6)	0.8028 (3)	0.7355 (5)	0.0694 (12)
H3A	0.8931	0.7859	0.7229	0.083*
H3B	0.7577	0.8070	0.8521	0.083*
C4	0.4649 (5)	0.7737 (2)	0.5910 (4)	0.0457 (9)
C5	0.3269 (5)	0.6153 (2)	0.5662 (5)	0.0552 (10)
H5A	0.4316	0.5966	0.5104	0.066*
H5B	0.3752	0.6153	0.6835	0.066*
C6	0.1541 (5)	0.4940 (2)	0.4149 (4)	0.0447 (8)
H6	0.2573	0.4895	0.3563	0.054*
C7	0.1553 (5)	0.5568 (2)	0.5287 (4)	0.0409 (8)
C8	−0.0019 (5)	0.5621 (2)	0.6133 (4)	0.0471 (9)
H8	−0.0046	0.6042	0.6900	0.056*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S1	0.0570 (6)	0.0447 (6)	0.0984 (9)	0.0025 (5)	0.0135 (6)	−0.0024 (5)
S2	0.0413 (5)	0.0431 (5)	0.0681 (7)	−0.0072 (4)	−0.0094 (4)	0.0057 (5)
N1	0.0331 (14)	0.0483 (17)	0.0468 (17)	0.0028 (12)	−0.0042 (13)	0.0158 (13)
C1	0.068 (3)	0.066 (3)	0.084 (3)	−0.019 (2)	0.027 (2)	−0.002 (2)
C2	0.056 (2)	0.058 (2)	0.051 (2)	−0.0226 (18)	0.0062 (18)	−0.0135 (19)
C3	0.058 (2)	0.077 (3)	0.067 (3)	−0.017 (2)	−0.011 (2)	0.013 (2)
C4	0.049 (2)	0.046 (2)	0.043 (2)	−0.0140 (16)	0.0127 (17)	−0.0051 (16)
C5	0.0438 (19)	0.043 (2)	0.074 (3)	−0.0050 (17)	−0.0040 (19)	0.0080 (19)
C6	0.0428 (18)	0.044 (2)	0.049 (2)	0.0019 (15)	0.0137 (16)	0.0023 (17)
C7	0.0390 (17)	0.0343 (18)	0.048 (2)	−0.0033 (14)	0.0018 (16)	0.0075 (15)
C8	0.053 (2)	0.0388 (19)	0.048 (2)	−0.0020 (16)	0.0062 (17)	−0.0091 (16)

Geometric parameters (Å, º)

S1—C4	1.764 (4)	C3—H3A	0.9700
S1—C2	1.850 (4)	C3—H3B	0.9700
S2—C4	1.759 (3)	C5—C7	1.509 (5)
S2—C5	1.822 (4)	C5—H5A	0.9700
N1—C4	1.289 (4)	C5—H5B	0.9700
N1—C3	1.401 (5)	C6—C7	1.380 (5)
C1—C2	1.509 (5)	C6—C8^i	1.382 (5)
C1—H1A	0.9600	C6—H6	0.9300
C1—H1B	0.9600	C7—C8	1.390 (5)
C1—H1C	0.9600	C8—C6^i	1.382 (5)
C2—C3	1.505 (5)	C8—H8	0.9300
C2—H2	0.9800
C4—S1—C2	88.30 (17)	H3A—C3—H3B	108.0
C4—S2—C5	99.09 (17)	N1—C4—S2	127.8 (3)
C4—N1—C3	113.7 (3)	N1—C4—S1	116.0 (3)
C2—C1—H1A	109.5	S2—C4—S1	116.2 (2)
C2—C1—H1B	109.5	C7—C5—S2	110.3 (2)
H1A—C1—H1B	109.5	C7—C5—H5A	109.6
C2—C1—H1C	109.5	S2—C5—H5A	109.6
H1A—C1—H1C	109.5	C7—C5—H5B	109.6
H1B—C1—H1C	109.5	S2—C5—H5B	109.6
C3—C2—C1	113.2 (4)	H5A—C5—H5B	108.1
C3—C2—S1	103.6 (2)	C7—C6—C8^i	120.9 (3)
C1—C2—S1	111.5 (3)	C7—C6—H6	119.5
C3—C2—H2	109.5	C8^i—C6—H6	119.5
C1—C2—H2	109.5	C6—C7—C8	118.0 (3)
S1—C2—H2	109.5	C6—C7—C5	120.9 (3)
N1—C3—C2	111.1 (3)	C8—C7—C5	121.0 (3)
N1—C3—H3A	109.4	C6^i—C8—C7	121.1 (3)
C2—C3—H3A	109.4	C6^i—C8—H8	119.5
N1—C3—H3B	109.4	C7—C8—H8	119.5
C2—C3—H3B	109.4
C4—S1—C2—C3	−21.6 (3)	C2—S1—C4—N1	12.2 (3)
C4—S1—C2—C1	100.4 (3)	C2—S1—C4—S2	−169.1 (2)
C4—N1—C3—C2	−21.6 (5)	C4—S2—C5—C7	170.0 (3)
C1—C2—C3—N1	−92.7 (4)	C8^i—C6—C7—C8	−0.4 (5)
S1—C2—C3—N1	28.2 (4)	C8^i—C6—C7—C5	176.5 (3)
C3—N1—C4—S2	−175.4 (3)	S2—C5—C7—C6	113.9 (3)
C3—N1—C4—S1	3.2 (4)	S2—C5—C7—C8	−69.3 (4)
C5—S2—C4—N1	7.4 (4)	C6—C7—C8—C6^i	0.4 (5)
C5—S2—C4—S1	−171.2 (2)	C5—C7—C8—C6^i	−176.5 (3)

Symmetry code: (i) −x, −y+1, −z+1.