(E,E)-N,N-Bis(2,6-difluoro-benzyl-idene)ethane-1,2-diamine.

The asymmetric unit of the title compound, C(16)H(12)F(4)N(2), comprises half of the potentially bidentate Schiff base ligand, with an inversion centre located at the mid-point of the central C-C bond. The crystal packing is stabilized by inter-molecular C-H⋯N and π-π inter-actions [centroid-centroid distance = 3.6793 (12) Å and inter-planar spacing = 3.4999 (7) Å].

Related literature

For background to the synthesis and structural variations of Schiff base ligands and their complexes, see: Granovski et al. (1993 ▶); Elmali et al. (2000 ▶).

Experimental

Crystal data

C16H12F4N2

M = 308.28

Monoclinic,

a = 7.3304 (10) Å

b = 10.5414 (15) Å

c = 9.2106 (13) Å

β = 105.487 (2)°

V = 685.89 (17) Å3

Z = 2

Mo Kα radiation

μ = 0.13 mm−1

T = 150 K

0.34 × 0.30 × 0.10 mm

Data collection

Bruker SMART 1K CCD area-detector diffractometer

Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T min = 0.958, T max = 0.987

4573 measured reflections

1203 independent reflections

1057 reflections with I > 2σ(I)

R int = 0.031

Refinement

R[F 2 > 2σ(F 2)] = 0.043

wR(F 2) = 0.124

S = 1.15

1203 reflections

100 parameters

H-atom parameters constrained

Δρmax = 0.27 e Å−3

Δρmin = −0.23 e Å−3

Data collection: SMART (Bruker, 2005 ▶); cell refinement: SAINT (Bruker, 2005 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ▶).

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536811044692/su2335sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811044692/su2335Isup2.hkl

Supplementary material file. DOI: 10.1107/S1600536811044692/su2335Isup3.cml

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

C16H12F4N2	F(000) = 316
Mr = 308.28	Dx = 1.493 Mg m−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 4055 reflections
a = 7.3304 (10) Å	θ = 2.9–28.3°
b = 10.5414 (15) Å	µ = 0.13 mm−1
c = 9.2106 (13) Å	T = 150 K
β = 105.487 (2)°	Plate, yellow
V = 685.89 (17) Å3	0.34 × 0.30 × 0.10 mm
Z = 2

Bruker SMART 1K CCD area-detector diffractometer	1203 independent reflections
Radiation source: fine-focus sealed tube	1057 reflections with I > 2σ(I)
graphite	Rint = 0.031
Detector resolution: 8.33 pixels mm-1	θmax = 25.0°, θmin = 3.0°
ω scans	h = −8→8
Absorption correction: multi-scan (SADABS; Bruker, 2005)	k = −12→12
Tmin = 0.958, Tmax = 0.987	l = −10→10
4573 measured reflections

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)] = 0.043	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.124	H-atom parameters constrained
S = 1.15	w = 1/[σ2(Fo2) + (0.0646P)2 + 0.2701P] where P = (Fo2 + 2Fc2)/3
1203 reflections	(Δ/σ)max < 0.001
100 parameters	Δρmax = 0.27 e Å−3
0 restraints	Δρmin = −0.23 e Å−3

Experimental. The low-temperature data were collected with the Oxford Cyrosystems Cryostream low-temperature attachment.

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.

	x	y	z	Uiso*/Ueq
F1	0.24616 (17)	0.28505 (10)	0.59397 (12)	0.0409 (4)
F2	0.29841 (19)	0.71120 (10)	0.45850 (14)	0.0434 (4)
N1	0.4481 (2)	0.46153 (14)	0.79618 (16)	0.0297 (4)
C1	0.5503 (3)	0.51558 (19)	0.9411 (2)	0.0334 (5)
H1A	0.5590	0.6088	0.9317	0.040*
H1B	0.6805	0.4809	0.9717	0.040*
C2	0.3868 (2)	0.53796 (16)	0.6894 (2)	0.0277 (4)
H2	0.4123	0.6256	0.7087	0.033*
C3	0.2783 (2)	0.50109 (15)	0.53673 (18)	0.0244 (4)
C4	0.2091 (2)	0.37948 (16)	0.49141 (19)	0.0272 (4)
C5	0.1031 (2)	0.35046 (18)	0.3480 (2)	0.0311 (5)
H5	0.0594	0.2664	0.3225	0.037*
C6	0.0615 (3)	0.44634 (19)	0.2419 (2)	0.0332 (5)
H6	−0.0123	0.4279	0.1426	0.040*
C7	0.1257 (3)	0.56853 (19)	0.2780 (2)	0.0330 (5)
H7	0.0974	0.6345	0.2052	0.040*
C8	0.2317 (2)	0.59168 (16)	0.4228 (2)	0.0287 (4)

	U11	U22	U33	U12	U13	U23
F1	0.0569 (8)	0.0217 (6)	0.0346 (6)	−0.0067 (5)	−0.0046 (5)	0.0054 (4)
F2	0.0677 (8)	0.0190 (6)	0.0419 (7)	0.0003 (5)	0.0118 (6)	0.0036 (5)
N1	0.0339 (8)	0.0273 (8)	0.0247 (8)	0.0032 (6)	0.0022 (6)	−0.0038 (6)
C1	0.0331 (10)	0.0355 (10)	0.0280 (10)	−0.0021 (8)	0.0020 (8)	−0.0042 (8)
C2	0.0331 (9)	0.0210 (9)	0.0287 (9)	−0.0031 (7)	0.0077 (7)	−0.0021 (7)
C3	0.0259 (8)	0.0230 (9)	0.0248 (9)	0.0035 (7)	0.0075 (7)	−0.0012 (7)
C4	0.0306 (9)	0.0228 (9)	0.0271 (9)	0.0030 (7)	0.0059 (7)	0.0027 (7)
C5	0.0312 (9)	0.0292 (10)	0.0308 (10)	−0.0017 (7)	0.0044 (8)	−0.0059 (7)
C6	0.0300 (9)	0.0421 (11)	0.0251 (9)	0.0044 (8)	0.0032 (7)	−0.0014 (8)
C7	0.0370 (10)	0.0349 (10)	0.0278 (10)	0.0101 (8)	0.0098 (8)	0.0082 (8)
C8	0.0357 (10)	0.0198 (9)	0.0324 (10)	0.0042 (7)	0.0124 (8)	0.0007 (7)

F1—C4	1.349 (2)	C3—C8	1.392 (2)
F2—C8	1.360 (2)	C3—C4	1.401 (3)
N1—C2	1.258 (2)	C4—C5	1.376 (3)
N1—C1	1.461 (2)	C5—C6	1.382 (3)
C1—C1i	1.502 (4)	C5—H5	0.950
C1—H1A	0.990	C6—C7	1.381 (3)
C1—H1B	0.990	C6—H6	0.950
C2—C3	1.471 (2)	C7—C8	1.374 (3)
C2—H2	0.950	C7—H7	0.950
C2—N1—C1	116.98 (16)	F1—C4—C3	118.52 (15)
N1—C1—C1i	110.12 (19)	C5—C4—C3	123.79 (16)
N1—C1—H1A	109.6	C4—C5—C6	118.53 (17)
C1i—C1—H1A	109.6	C4—C5—H5	120.7
N1—C1—H1B	109.6	C6—C5—H5	120.7
C1i—C1—H1B	109.6	C7—C6—C5	120.98 (17)
H1A—C1—H1B	108.1	C7—C6—H6	119.5
N1—C2—C3	124.56 (16)	C5—C6—H6	119.5
N1—C2—H2	117.7	C8—C7—C6	117.89 (18)
C3—C2—H2	117.7	C8—C7—H7	121.1
C8—C3—C4	114.00 (15)	C6—C7—H7	121.1
C8—C3—C2	120.03 (15)	F2—C8—C7	118.23 (17)
C4—C3—C2	125.95 (15)	F2—C8—C3	116.95 (16)
F1—C4—C5	117.69 (16)	C7—C8—C3	124.81 (17)
C2—N1—C1—C1i	119.1 (2)	C3—C4—C5—C6	−0.1 (3)
C1—N1—C2—C3	−178.90 (15)	C4—C5—C6—C7	0.4 (3)
N1—C2—C3—C8	−174.14 (17)	C5—C6—C7—C8	−0.1 (3)
N1—C2—C3—C4	7.6 (3)	C6—C7—C8—F2	178.75 (15)
C8—C3—C4—F1	−179.76 (15)	C6—C7—C8—C3	−0.6 (3)
C2—C3—C4—F1	−1.4 (3)	C4—C3—C8—F2	−178.50 (14)
C8—C3—C4—C5	−0.5 (3)	C2—C3—C8—F2	3.0 (2)
C2—C3—C4—C5	177.93 (16)	C4—C3—C8—C7	0.8 (3)
F1—C4—C5—C6	179.17 (15)	C2—C3—C8—C7	−177.67 (16)

D—H···A	D—H	H···A	D···A	D—H···A
C5—H5···N1ii	0.95	2.53	3.471 (2)	171

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C5—H5⋯N1i	0.95	2.53	3.471 (2)	171

Symmetry code: (i) .