N,N'-Bis[(E)-1-(thio­phen-3-yl)ethyl­idene]ethane-1,2-diamine

The complete mol­ecule of the title compound, C₁₄H₁₆N₂S₂, is generated by a crystallographic inversion centre. The thio­phene residue is close to being coplanar with the imine group [C-C-C-N torsion angle = 6.5 (2)°], and the conformation about the imine C=N bond [1.281 (2) Å] is E. In the crystal, the three-dimensional architecture is consolidated by C-H...N, C-H...[pi] and S...S [3.3932 (7) Å] inter­actions.

Key indicators

• Single-crystal X-ray study
• T = 100 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.039
• wR factor = 0.105
• Data-to-parameter ratio = 18.6

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.600          7
PLAT912_ALERT_4_C Missing # of FCF Reflections Above STh/L=  0.600          7

Alert level G
PLAT005_ALERT_5_G No _iucr_refine_instructions_details in CIF ....          ?
PLAT153_ALERT_1_G The su's on the Cell Axes   are Equal ..........    0.00060 Ang.

   0 ALERT level A = Most likely a serious problem - resolve or explain
   0 ALERT level B = A potentially serious problem, consider carefully
   2 ALERT level C = Check. Ensure it is not caused by an omission or oversight
   2 ALERT level G = General information/check it is not something unexpected

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 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
   1 ALERT type 4 Improvement, methodology, query or suggestion
   1 ALERT type 5 Informative message, check

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S1. Comment

Thiophenes attract attention for their biological activity amongst other properties (Kleemann et al., 2006). In continuation of structural studies of thienyl derivatives (Prasath et al., 2010a; Prasath et al., 2010b), herein the title compound, bis[1-(thiophen-3-yl)ethylidene]ethane-1,2-diamine (I), is described.

The asymmetric unit in (I), Fig. 1, comprises half a molecule with the full molecule generated by a crystallographic centre of inversion. The thiophene residue is co-planar with the imine group as seen in the value of the C2—C3—C5—N1 torsion angle of 6.5 (2) °. In fact the entire molecule is planar with the r.m.s. deviation for the 18 non-hydrogen atoms being 0.068 Å; the maximum deviations are found for the S1 [0.092 (1) Å] and C2 [-0.099 (2) Å] atoms. The conformation about the imine N1—C5 bond [1.281 (2) Å] is E.

In the crystal packing the molecules associate via C—H···N, C—H···π, [Table 1] and S···S [S1···S1ⁱ = 3.3932 (7) Å for i: 2 - x, 1 - y, 2 - z] interactions to form a three-dimensional architecture, Fig. 2.

Related literature

For background to 2-substituted thiophenes, see: Kleemann et al. (2006). For related structures, see: Prasath et al. (2010a,b).

S2. Experimental

A mixture of ethylenediamine (0.6 g, 0.01 M) and 2-acetyl thiophene (0.7 g, 0.01 M) in dry benzene (50 ml) was refluxed using a Dean-Stark trap until no more water was collected (2 h). The benzene was then removed under reduced pressure and the residue treated with methanol. The solid that separated out was recrystallized from ethanol as colourless prisms. Yield: 72%. M.pt: 405–407 K.

S3. Refinement

Carbon-bound H-atoms were placed in calculated positions [C—H = 0.95 to 0.99 Å, U_iso(H) = 1.2 to 1.5U_eq(C)] and were included in the refinement in the riding model approximation.

Computing details

Data collection: CrysAlis PRO (Agilent, 2011); cell refinement: CrysAlis PRO (Agilent, 2011); data reduction: CrysAlis PRO (Agilent, 2011); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and DIAMOND (Brandenburg, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures

	Fig. 1. The molecular structure of (I) showing displacement ellipsoids at the 50% probability level. The unlabelled atoms are related by the symmetry operation (1-x, 1-y, -z).
	Fig. 2. A view in projection down the c axis of the unit-cell contents of (I). The C—N···N, C—H···π and S···S interactions are shown as blue, purple and orange dashed lines, respectively.

N,N'-Bis[(E)-1-(thiophen-3-yl)ethylidene]ethane-1,2-diamine

Crystal data

C14H16N2S2	F(000) = 292
Mr = 276.41	Dx = 1.372 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 1637 reflections
a = 7.5231 (6) Å	θ = 2.6–27.5°
b = 11.2338 (6) Å	µ = 0.38 mm^−1
c = 8.5967 (6) Å	T = 100 K
β = 112.894 (9)°	Prism, colourless
V = 669.30 (8) Å^3	0.20 × 0.15 × 0.10 mm
Z = 2

Data collection

Agilent SuperNova Dual diffractometer with an Atlas detector	1542 independent reflections
Radiation source: SuperNova (Mo) X-ray Source	1339 reflections with I > 2σ(I)
Mirror monochromator	Rint = 0.033
Detector resolution: 10.4041 pixels mm^-1	θmax = 27.6°, θmin = 2.9°
ω scan	h = −9→9
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2011)	k = −14→9
Tmin = 0.928, Tmax = 0.963	l = −11→7
2789 measured reflections

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)] = 0.039	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.105	H-atom parameters constrained
S = 1.06	w = 1/[σ^2(Fo^2) + (0.0482P)^2 + 0.3751P] where P = (Fo^2 + 2Fc^2)/3
1542 reflections	(Δ/σ)max = 0.001
83 parameters	Δρmax = 0.45 e Å^−3
0 restraints	Δρmin = −0.41 e Å^−3

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
S1	0.88734 (7)	0.59544 (4)	0.83858 (6)	0.01735 (17)
N1	0.6122 (2)	0.51740 (13)	0.23310 (18)	0.0129 (3)
C1	0.7443 (3)	0.69397 (16)	0.6897 (2)	0.0161 (4)
H1	0.7138	0.7719	0.7143	0.019*
C2	0.6805 (3)	0.64614 (16)	0.5325 (2)	0.0138 (4)
H2	0.5985	0.6872	0.4342	0.017*
C3	0.7493 (2)	0.52741 (15)	0.5294 (2)	0.0127 (4)
C4	0.8632 (3)	0.48878 (16)	0.6889 (2)	0.0151 (4)
H4	0.9214	0.4123	0.7133	0.018*
C5	0.7023 (2)	0.45986 (15)	0.3700 (2)	0.0121 (4)
C6	0.7668 (3)	0.33137 (16)	0.3829 (2)	0.0156 (4)
H6A	0.6939	0.2903	0.2764	0.023*
H6B	0.7435	0.2923	0.4751	0.023*
H6C	0.9049	0.3283	0.4055	0.023*
C7	0.5591 (3)	0.45805 (16)	0.0702 (2)	0.0144 (4)
H7A	0.4831	0.3856	0.0675	0.017*
H7B	0.6771	0.4338	0.0537	0.017*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S1	0.0200 (3)	0.0185 (3)	0.0112 (3)	0.00100 (18)	0.00349 (19)	−0.00088 (17)
N1	0.0144 (8)	0.0129 (7)	0.0110 (7)	−0.0001 (6)	0.0043 (6)	−0.0005 (6)
C1	0.0183 (9)	0.0150 (8)	0.0170 (9)	0.0011 (7)	0.0091 (7)	0.0012 (7)
C2	0.0147 (9)	0.0151 (9)	0.0128 (8)	0.0013 (7)	0.0065 (7)	0.0023 (7)
C3	0.0124 (8)	0.0129 (8)	0.0134 (9)	−0.0012 (7)	0.0057 (7)	0.0010 (7)
C4	0.0171 (9)	0.0137 (8)	0.0136 (9)	0.0003 (7)	0.0052 (7)	0.0001 (7)
C5	0.0101 (8)	0.0123 (8)	0.0146 (9)	−0.0011 (6)	0.0055 (7)	−0.0006 (7)
C6	0.0184 (9)	0.0125 (8)	0.0158 (9)	0.0020 (7)	0.0064 (7)	0.0004 (7)
C7	0.0177 (9)	0.0124 (8)	0.0121 (9)	0.0005 (7)	0.0047 (7)	−0.0024 (7)

Geometric parameters (Å, º)

S1—C4	1.7154 (18)	C3—C5	1.484 (2)
S1—C1	1.7174 (19)	C4—H4	0.9500
N1—C5	1.281 (2)	C5—C6	1.513 (2)
N1—C7	1.460 (2)	C6—H6A	0.9800
C1—C2	1.357 (2)	C6—H6B	0.9800
C1—H1	0.9500	C6—H6C	0.9800
C2—C3	1.435 (2)	C7—C7^i	1.517 (3)
C2—H2	0.9500	C7—H7A	0.9900
C3—C4	1.374 (2)	C7—H7B	0.9900
C4—S1—C1	92.19 (9)	N1—C5—C6	126.06 (15)
C5—N1—C7	120.01 (15)	C3—C5—C6	117.77 (15)
C2—C1—S1	111.31 (14)	C5—C6—H6A	109.5
C2—C1—H1	124.3	C5—C6—H6B	109.5
S1—C1—H1	124.3	H6A—C6—H6B	109.5
C1—C2—C3	113.35 (16)	C5—C6—H6C	109.5
C1—C2—H2	123.3	H6A—C6—H6C	109.5
C3—C2—H2	123.3	H6B—C6—H6C	109.5
C4—C3—C2	111.37 (16)	N1—C7—C7^i	109.65 (18)
C4—C3—C5	126.30 (16)	N1—C7—H7A	109.7
C2—C3—C5	122.32 (15)	C7^i—C7—H7A	109.7
C3—C4—S1	111.78 (14)	N1—C7—H7B	109.7
C3—C4—H4	124.1	C7^i—C7—H7B	109.7
S1—C4—H4	124.1	H7A—C7—H7B	108.2
N1—C5—C3	116.16 (15)
C4—S1—C1—C2	0.34 (14)	C7—N1—C5—C3	−179.72 (15)
S1—C1—C2—C3	−0.7 (2)	C7—N1—C5—C6	1.3 (3)
C1—C2—C3—C4	0.8 (2)	C4—C3—C5—N1	−172.11 (17)
C1—C2—C3—C5	−177.97 (16)	C2—C3—C5—N1	6.5 (2)
C2—C3—C4—S1	−0.6 (2)	C4—C3—C5—C6	7.0 (3)
C5—C3—C4—S1	178.19 (14)	C2—C3—C5—C6	−174.39 (15)
C1—S1—C4—C3	0.13 (15)	C5—N1—C7—C7^i	175.58 (18)

Symmetry code: (i) −x+1, −y+1, −z.

Hydrogen-bond geometry (Å, º)

Cg1 is the centroid of the S1,C1–C4 ring.

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1···N1^ii	0.95	2.51	3.454 (2)	172
C6—H6C···Cg1^iii	0.98	2.74	3.624 (2)	150

Symmetry codes: (ii) x, −y+3/2, z+1/2; (iii) −x+2, −y+1, −z+1.