(1R,2R)-Bis(4-pyridyl­methyl­ene­amino)­cyclo­hexane

The two imine moieties of the title compound, C₁₈H₂₀N₄, are positioned equatorially on the chair-conformation cyclo­hexane ring. Both also show a trans configuration with respect to the C=N double bond. The mol­ecule lies on a crystallographic twofold rotation in a non-centrosymmetric space group. The dihedral angle between the two least-squares planes of the pyridine rings is 56.6 (2)°.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.053
• wR factor = 0.143
• Data-to-parameter ratio = 14.7

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

General Notes



REFLT_03
         From the CIF: _diffrn_reflns_theta_max           25.00
         From the CIF: _reflns_number_total               1473
         Count of symmetry unique reflns          889
         Completeness (_total/calc)            165.69%
         TEST3: Check Friedels for noncentro structure
         Estimate of Friedel pairs measured       584
         Fraction of Friedel pairs measured     0.657
         Are heavy atom types Z>Si present           no
          ALERT: MoKa measured Friedel data cannot be used to
                 determine absolute structure in a light-atom
                 study EXCEPT under VERY special conditions.
                 It is preferred that Friedel data is merged in such cases.

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Computing details

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

(1R,2R)-Bis(4-pyridylmethyleneamino)cyclohexane

Crystal data

C18H20N4	Dx = 1.170 Mg m^−3
Mr = 292.38	Melting point = 407–409 K
Orthorhombic, P21212	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2 2ab	Cell parameters from 1006 reflections
a = 15.230 (4) Å	θ = 2.6–25.5°
b = 5.789 (1) Å	µ = 0.07 mm^−1
c = 9.415 (2) Å	T = 293 K
V = 830.0 (3) Å^3	Block, colorless
Z = 2	0.3 × 0.2 × 0.2 mm
F(000) = 312

Data collection

Bruker CCD area-detector diffractometer	1473 independent reflections
Radiation source: sealed tube	1288 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.051
φ and ω scans	θmax = 25.0°, θmin = 2.2°
Absorption correction: empirical (using intensity measurements) (SADABS; Sheldrick, 1996)	h = −17→18
Tmin = 0.983, Tmax = 0.986	k = −6→6
4258 measured reflections	l = −11→6

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)] = 0.053	H-atom parameters constrained
wR(F^2) = 0.143	w = 1/[σ^2(Fo^2) + (0.1P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.01	(Δ/σ)max < 0.001
1473 reflections	Δρmax = 0.13 e Å^−3
100 parameters	Δρmin = −0.26 e Å^−3
0 restraints	Absolute structure: Flack (1983); 584 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.0018 (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
C1	0.36087 (19)	0.5747 (5)	0.2450 (3)	0.0958 (9)
H1	0.3864	0.7185	0.2297	0.115*
C2	0.38240 (14)	0.4610 (4)	0.3675 (3)	0.0738 (6)
H2	0.4208	0.5272	0.4326	0.089*
C3	0.34617 (12)	0.2459 (4)	0.3930 (2)	0.0593 (6)
C4	0.28680 (13)	0.1598 (5)	0.2941 (2)	0.0738 (7)
H4	0.2590	0.0186	0.3081	0.089*
C5	0.27040 (18)	0.2919 (7)	0.1735 (3)	0.0927 (9)
H5	0.2314	0.2329	0.1067	0.111*
C6	0.37032 (11)	0.1118 (4)	0.5197 (2)	0.0560 (5)
H6	0.3391	−0.0218	0.5412	0.067*
C7	0.45115 (12)	0.0325 (3)	0.72348 (19)	0.0542 (5)
H7	0.4156	−0.1086	0.7206	0.065*
C8	0.42892 (12)	0.1681 (4)	0.8567 (2)	0.0659 (6)
H8A	0.4608	0.3132	0.8558	0.079*
H8B	0.3666	0.2033	0.8570	0.079*
C9	0.45190 (14)	0.0359 (5)	0.9902 (2)	0.0738 (7)
H9A	0.4152	−0.1006	0.9968	0.089*
H9B	0.4402	0.1318	1.0725	0.089*
N1	0.30656 (18)	0.4962 (6)	0.1469 (2)	0.1044 (9)
N2	0.43171 (10)	0.1731 (3)	0.59912 (18)	0.0612 (5)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.111 (2)	0.1001 (19)	0.0759 (17)	0.0366 (16)	0.0153 (16)	0.0260 (15)
C2	0.0718 (13)	0.0825 (14)	0.0672 (14)	0.0128 (12)	0.0071 (11)	0.0115 (13)
C3	0.0472 (10)	0.0775 (13)	0.0532 (11)	0.0140 (9)	0.0062 (8)	0.0003 (10)
C4	0.0577 (12)	0.1015 (16)	0.0622 (13)	0.0223 (11)	−0.0040 (9)	−0.0129 (13)
C5	0.0758 (16)	0.140 (3)	0.0623 (16)	0.0455 (18)	−0.0089 (12)	−0.0145 (18)
C6	0.0466 (10)	0.0662 (11)	0.0552 (11)	−0.0033 (9)	0.0035 (8)	0.0034 (9)
C7	0.0507 (10)	0.0590 (10)	0.0528 (10)	−0.0094 (8)	−0.0013 (8)	0.0061 (9)
C8	0.0528 (10)	0.0818 (13)	0.0632 (12)	0.0045 (9)	0.0011 (9)	−0.0023 (12)
C9	0.0637 (12)	0.1081 (17)	0.0497 (12)	0.0045 (13)	0.0041 (9)	−0.0030 (13)
N1	0.1075 (18)	0.139 (2)	0.0667 (14)	0.0576 (18)	0.0014 (13)	0.0165 (18)
N2	0.0581 (10)	0.0686 (10)	0.0569 (10)	−0.0084 (8)	−0.0031 (8)	0.0060 (8)

Geometric parameters (Å, º)

C1—N1	1.321 (4)	C6—H6	0.9300
C1—C2	1.368 (3)	C7—N2	1.456 (2)
C1—H1	0.9300	C7—C8	1.518 (3)
C2—C3	1.383 (3)	C7—C7^i	1.535 (4)
C2—H2	0.9300	C7—H7	0.9800
C3—C4	1.390 (3)	C8—C9	1.513 (3)
C3—C6	1.470 (3)	C8—H8A	0.9700
C4—C5	1.392 (4)	C8—H8B	0.9700
C4—H4	0.9300	C9—C9^i	1.523 (4)
C5—N1	1.328 (5)	C9—H9A	0.9700
C5—H5	0.9300	C9—H9B	0.9700
C6—N2	1.249 (2)
N1—C1—C2	125.0 (3)	N2—C7—C7^i	109.51 (13)
N1—C1—H1	117.5	C8—C7—C7^i	110.06 (13)
C2—C1—H1	117.5	N2—C7—H7	109.3
C1—C2—C3	119.0 (3)	C8—C7—H7	109.3
C1—C2—H2	120.5	C7^i—C7—H7	109.3
C3—C2—H2	120.5	C9—C8—C7	111.90 (17)
C2—C3—C4	117.8 (2)	C9—C8—H8A	109.2
C2—C3—C6	121.1 (2)	C7—C8—H8A	109.2
C4—C3—C6	121.1 (2)	C9—C8—H8B	109.2
C3—C4—C5	117.8 (2)	C7—C8—H8B	109.2
C3—C4—H4	121.1	H8A—C8—H8B	107.9
C5—C4—H4	121.1	C8—C9—C9^i	111.14 (16)
N1—C5—C4	124.6 (3)	C8—C9—H9A	109.4
N1—C5—H5	117.7	C9^i—C9—H9A	109.4
C4—C5—H5	117.7	C8—C9—H9B	109.4
N2—C6—C3	121.56 (19)	C9^i—C9—H9B	109.4
N2—C6—H6	119.2	H9A—C9—H9B	108.0
C3—C6—H6	119.2	C1—N1—C5	115.8 (2)
N2—C7—C8	109.25 (15)	C6—N2—C7	118.36 (16)

Symmetry code: (i) −x+1, −y, z.