N,N'-Bis(2-thienylmethyl­ene)ethane-1,2-diamine

The title compound, C₁₂H₁₂N₂S₂, was prepared from a condensation reaction of thio­phene-2-carboxaldehyde with ethyl­enediamine in refluxing ethanol. The mol­ecule adopts a Z-shaped conformation, with the two thio­phene rings lying on either side of the Csp³-Csp³ bond. The two thio­phene rings form a dihedral angle of 11.2 (2)°. The crystal packing is mainly stabilized by van der Waals forces.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.007 Å
• R factor = 0.044
• wR factor = 0.081
• Data-to-parameter ratio = 11.5

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT340_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang ...          7

Alert level G
REFLT03_ALERT_4_G  WARNING: Large fraction of Friedel related reflns may
                     be needed to determine absolute structure
           From the CIF: _diffrn_reflns_theta_max           25.01
           From the CIF: _reflns_number_total               1663
           Count of symmetry unique reflns         1186
           Completeness (_total/calc)            140.22%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured       477
           Fraction of Friedel pairs measured     0.402
           Are heavy atom types Z>Si present        yes
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          1

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   1 ALERT level C = Check and explain
   2 ALERT level G = General alerts; check

   0 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
   2 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

Multi-dentate complexes of iron and nickel show high activities of ethylene oligomerization and polymerization (Ittle et al., 2000). We report here the crystal structure of the title compound, a new multidentate Schiff base compound.

The molecular structure of the title compound is shown in Fig.1. The molecule adopts a Z-shaped conformation, with the two thiophene rings lying on either side of the C11—C12 bond. The torsion angles C11—N1—C1—C2 [-177.9 (4)°], N1—C11—C12—N2 [178.9 (4)°] and C12—N2—C6—C7 [-176.2 (4)°] describe the overall conformation of the molecule. The two thiophene rings form a dihedral angle of 11.2 (2)°. The crystal packing is mainly stabilized by van der Waals forces.

Related literature

For general background, see: Ittle et al. (2000).

S2. Experimental

A absolute ethanol mixture of thiophene-2-carboxaldehyde (4 mmol) and ethyldiamine (2 mmol) was heated under reflux with stirring for 1.5 h and then filtered to obtain a clear pale yellow solution. Single crystals of the title compound suitable for X-ray diffraction analysis were obtained by vapour diffusion of diethyl ether into the yellow solution.

S3. Refinement

H atoms were positioned geometrically [C—H = 0.93 (aromatic) or 0.97 Å (methylene)] and refined using a riding model, with U_iso(H) = 1.2U_eq(C).

Computing details

Data collection: SMART (Siemens, 1996); cell refinement: SAINT (Siemens, 1996); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997a); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997a); molecular graphics: SHELXTL (Sheldrick, 1997b); software used to prepare material for publication: SHELXTL.

Figures

	Fig. 1. The molecular structure of the title compound, showing 30% probability displacement ellipsoids and the atom-numbering scheme.
	Fig. 2. The crystal packing of the title compound, viewed approximately along the a axis.

N,N'-Bis(2-thienylmethylene)ethane-1,2-diamine

Crystal data

C12H12N2S2	F(000) = 260
Mr = 248.36	Dx = 1.331 Mg m^−3
Monoclinic, P21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2yb	Cell parameters from 1008 reflections
a = 6.4822 (8) Å	θ = 3.2–27.4°
b = 7.4181 (10) Å	µ = 0.40 mm^−1
c = 13.1433 (15) Å	T = 298 K
β = 101.425 (2)°	Block, yellow
V = 619.48 (13) Å^3	0.36 × 0.13 × 0.08 mm
Z = 2

Data collection

Siemens SMART CCD area-detector diffractometer	1663 independent reflections
Radiation source: fine-focus sealed tube	1136 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.046
ϕ and ω scans	θmax = 25.0°, θmin = 1.6°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −7→7
Tmin = 0.869, Tmax = 0.969	k = −8→5
3150 measured reflections	l = −13→15

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)] = 0.044	H-atom parameters constrained
wR(F^2) = 0.081	w = 1/[σ^2(Fo^2) + (0.0294P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.03	(Δ/σ)max = 0.001
1663 reflections	Δρmax = 0.19 e Å^−3
145 parameters	Δρmin = −0.26 e Å^−3
1 restraint	Absolute structure: Flack (1983); 481 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: −0.03 (12)

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	0.08972 (17)	0.55346 (16)	0.29575 (9)	0.0620 (4)
S2	0.98557 (19)	0.38242 (15)	0.95907 (9)	0.0589 (4)
N1	0.3457 (6)	0.4695 (4)	0.5119 (3)	0.0544 (10)
N2	0.7400 (6)	0.5301 (5)	0.7551 (3)	0.0562 (10)
C1	0.1512 (8)	0.4405 (6)	0.4996 (3)	0.0543 (14)
H1	0.0983	0.3942	0.5550	0.065*
C2	0.0056 (7)	0.4765 (5)	0.4024 (3)	0.0473 (12)
C3	−0.2071 (7)	0.4550 (6)	0.3820 (4)	0.0607 (14)
H3	−0.2828	0.4144	0.4307	0.073*
C4	−0.3001 (8)	0.5010 (7)	0.2791 (4)	0.0668 (15)
H4	−0.4439	0.4944	0.2524	0.080*
C5	−0.1594 (7)	0.5547 (8)	0.2245 (4)	0.0625 (13)
H5	−0.1935	0.5891	0.1552	0.075*
C6	0.9347 (7)	0.5520 (7)	0.7699 (3)	0.0514 (12)
H6	0.9913	0.6062	0.7177	0.062*
C7	1.0773 (7)	0.4971 (5)	0.8644 (3)	0.0460 (11)
C8	1.2899 (7)	0.5175 (7)	0.8889 (3)	0.0634 (14)
H8	1.3693	0.5765	0.8474	0.076*
C9	1.3748 (8)	0.4369 (7)	0.9864 (4)	0.0738 (17)
H9	1.5177	0.4373	1.0156	0.089*
C10	1.2317 (8)	0.3615 (7)	1.0316 (4)	0.0616 (14)
H10	1.2623	0.3037	1.0956	0.074*
C11	0.4766 (7)	0.4224 (6)	0.6113 (3)	0.0619 (14)
H11A	0.5646	0.3200	0.6027	0.074*
H11B	0.3880	0.3884	0.6596	0.074*
C12	0.6137 (7)	0.5800 (6)	0.6546 (3)	0.0627 (14)
H12A	0.7049	0.6127	0.6073	0.075*
H12B	0.5264	0.6833	0.6625	0.075*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S1	0.0541 (8)	0.0700 (9)	0.0616 (8)	−0.0122 (7)	0.0105 (6)	0.0102 (7)
S2	0.0584 (9)	0.0623 (8)	0.0572 (8)	−0.0005 (7)	0.0144 (7)	0.0098 (6)
N1	0.055 (2)	0.061 (3)	0.045 (2)	0.000 (2)	0.004 (2)	0.0015 (17)
N2	0.062 (3)	0.055 (3)	0.047 (2)	0.007 (2)	0.002 (2)	0.001 (2)
C1	0.073 (4)	0.048 (3)	0.043 (3)	−0.005 (3)	0.015 (3)	−0.005 (2)
C2	0.050 (3)	0.043 (3)	0.050 (3)	−0.006 (2)	0.011 (2)	−0.007 (2)
C3	0.052 (3)	0.070 (4)	0.066 (4)	−0.018 (3)	0.026 (3)	−0.015 (3)
C4	0.048 (3)	0.070 (4)	0.080 (4)	−0.006 (3)	0.006 (3)	−0.009 (3)
C5	0.061 (3)	0.059 (3)	0.060 (3)	−0.006 (3)	−0.006 (3)	0.005 (3)
C6	0.072 (3)	0.040 (3)	0.043 (3)	−0.001 (3)	0.012 (3)	0.000 (2)
C7	0.055 (3)	0.041 (3)	0.043 (3)	0.000 (2)	0.014 (2)	−0.001 (2)
C8	0.056 (3)	0.076 (4)	0.060 (3)	−0.017 (3)	0.017 (3)	−0.001 (3)
C9	0.053 (3)	0.094 (4)	0.066 (4)	−0.008 (3)	−0.009 (3)	−0.005 (3)
C10	0.060 (3)	0.065 (4)	0.054 (3)	−0.001 (3)	−0.001 (3)	0.009 (3)
C11	0.072 (3)	0.063 (4)	0.047 (3)	0.002 (3)	0.002 (3)	0.007 (2)
C12	0.076 (3)	0.059 (3)	0.047 (3)	0.005 (3)	−0.001 (3)	0.006 (2)

Geometric parameters (Å, º)

S1—C5	1.699 (4)	C5—H5	0.93
S1—C2	1.700 (4)	C6—C7	1.452 (5)
S2—C10	1.696 (5)	C6—H6	0.93
S2—C7	1.708 (4)	C7—C8	1.360 (5)
N1—C1	1.257 (5)	C8—C9	1.422 (6)
N1—C11	1.453 (5)	C8—H8	0.93
N2—C6	1.249 (5)	C9—C10	1.320 (6)
N2—C12	1.457 (5)	C9—H9	0.93
C1—C2	1.455 (6)	C10—H10	0.93
C1—H1	0.93	C11—C12	1.510 (5)
C2—C3	1.361 (6)	C11—H11A	0.97
C3—C4	1.409 (6)	C11—H11B	0.97
C3—H3	0.93	C12—H12A	0.97
C4—C5	1.328 (6)	C12—H12B	0.97
C4—H4	0.93
C5—S1—C2	91.8 (2)	C8—C7—S2	111.4 (3)
C10—S2—C7	91.7 (2)	C6—C7—S2	120.6 (3)
C1—N1—C11	117.8 (4)	C7—C8—C9	111.1 (4)
C6—N2—C12	118.5 (4)	C7—C8—H8	124.5
N1—C1—C2	122.8 (4)	C9—C8—H8	124.5
N1—C1—H1	118.6	C10—C9—C8	113.7 (4)
C2—C1—H1	118.6	C10—C9—H9	123.1
C3—C2—C1	127.4 (4)	C8—C9—H9	123.1
C3—C2—S1	110.8 (3)	C9—C10—S2	112.0 (4)
C1—C2—S1	121.8 (3)	C9—C10—H10	124.0
C2—C3—C4	112.6 (4)	S2—C10—H10	124.0
C2—C3—H3	123.7	N1—C11—C12	110.4 (3)
C4—C3—H3	123.7	N1—C11—H11A	109.6
C5—C4—C3	112.5 (4)	C12—C11—H11A	109.6
C5—C4—H4	123.8	N1—C11—H11B	109.6
C3—C4—H4	123.8	C12—C11—H11B	109.6
C4—C5—S1	112.3 (4)	H11A—C11—H11B	108.1
C4—C5—H5	123.8	N2—C12—C11	109.2 (4)
S1—C5—H5	123.8	N2—C12—H12A	109.8
N2—C6—C7	123.3 (4)	C11—C12—H12A	109.8
N2—C6—H6	118.4	N2—C12—H12B	109.8
C7—C6—H6	118.4	C11—C12—H12B	109.8
C8—C7—C6	127.9 (4)	H12A—C12—H12B	108.3
C11—N1—C1—C2	−177.9 (4)	N2—C6—C7—S2	4.7 (7)
N1—C1—C2—C3	−177.9 (4)	C10—S2—C7—C8	−0.1 (4)
N1—C1—C2—S1	2.4 (6)	C10—S2—C7—C6	177.0 (4)
C5—S1—C2—C3	−0.4 (4)	C6—C7—C8—C9	−176.7 (4)
C5—S1—C2—C1	179.2 (4)	S2—C7—C8—C9	0.2 (5)
C1—C2—C3—C4	−179.4 (4)	C7—C8—C9—C10	−0.2 (6)
S1—C2—C3—C4	0.2 (5)	C8—C9—C10—S2	0.2 (6)
C2—C3—C4—C5	0.2 (6)	C7—S2—C10—C9	−0.1 (4)
C3—C4—C5—S1	−0.5 (6)	C1—N1—C11—C12	−128.7 (4)
C2—S1—C5—C4	0.6 (5)	C6—N2—C12—C11	127.3 (5)
C12—N2—C6—C7	−176.2 (4)	N1—C11—C12—N2	178.9 (4)
N2—C6—C7—C8	−178.7 (5)