(IUCr) Crystallography Journals Online

Abstract top

In the title compound, C₃₂H₂₈N₂·CH₂Cl₂, the complete Schiff base and solvent molecules are both generated by crystallographic twofold axes, with the two C atoms of the former and the C atom of the latter lying on the rotation axis. The central benzene ring is substituted with two chiral groups including imine functionalities, with the common E configuration. The dihedral angle between the central benzene ring and the terminal naphthalene ring is 45.42 (9)° and that between the two naphthalene rings is 89.16 (8)°. The conformation of the Schiff base allows solvent molecules to fill the voids in the crystal, affording a stable 1:1 solvate, but the solvent interacts poorly with the Schiff base, as reflected by its rather high displacement parameters.

Comment top

During the last few decades, a central objective in synthetic organic chemistry has been to develop greener and more economically competitive processes for the efficient synthesis of compounds with potential applications in diverse fields. In this context, the solvent-free approach is simple with amazing versatility because it reduces the use of organic solvents and minimizes the formation of other waste. Likewise, the reactions occur under mild conditions and usually require easier workup procedures and simpler equipment. Moreover, it may allow access to compounds that require harsh reaction conditions under traditional approaches or when the yields are too low to be of practical convenience (Jeon et al., 2005; Noyori, 2005; Tanaka & Toda, 2000).

On the other hand, bisimines have lately attracted much attention, mostly due to their versatile coordination behavior and the interesting properties of their metal complexes. These compounds are particularly interesting since they can potentially act in a variety of coordination modes.

Continuing our work on the synthesis of chiral imines (Tovar et al., 2007), we synthesized the title Schiff base under solvent-free conditions and report here its X-ray structure. The asymmetric unit contains one half-molecule and one half dichloromethane molecule, both placed on binary axis (Fig. 1). This arrangement is probably favored by the presence of a chiral center, C6, allowing to orient the substituents of the imine functionality towards the opposite faces of the central benzene core. The crystal is further stabilized by the inclusion of lattice solvent, resulting in a 1:1 solvate. Indeed, the shape of the Schiff base is suitable for the formation of a guest-host complex (Fig. 2). However, as no efficient hydrogen bonds are formed, the solvent molecule presents high displacement parameters, compared to the host (See Fig. 1).

1,3-Bis{(+)-(S)-[1-(1-naphthyl)ethyl]iminomethyl}benzene dichloromethane solvate top

Crystal data top

C₃₂H₂₈N₂·CH₂Cl₂	D_x = 1.237 Mg m⁻³
M_r = 525.49	Melting point: 343 K
Orthorhombic, P2₁2₁2	Mo Kα radiation λ = 0.71073 Å
Hall symbol: P 2 2ab	Cell parameters from 51 reflections
a = 8.550 (2) Å	θ = 4.0–11.9º
b = 20.706 (6) Å	µ = 0.25 mm⁻¹
c = 7.972 (3) Å	T = 298 K
V = 1411.3 (7) Å³	Prism, yellow
Z = 2	0.40 × 0.24 × 0.20 mm
F₀₀₀ = 552

Data collection top

Siemens P4 diffractometer	R_int = 0.060
Radiation source: fine-focus sealed tube	θ_max = 25.0º
Monochromator: graphite	θ_min = 2.0º
T = 298 K	h = −10→10
2θ/ω scans	k = −24→24
Absorption correction: gaussian (XSCANS; Siemens, 1996)	l = −9→9
T_min = 0.933, T_max = 0.954	3 standard reflections
6308 measured reflections	every 97 reflections
2497 independent reflections	intensity decay: 2.3%
1428 reflections with I > 2σ(I)

Refinement top

Refinement on F²	H-atom parameters constrained
Least-squares matrix: full	w = 1/[σ²(F_o²) + (0.0833P)² + 0.2257P] where P = (F_o² + 2F_c²)/3
R[F² > 2σ(F²)] = 0.060	(Δ/σ)_max < 0.001
wR(F²) = 0.186	Δρ_max = 0.19 e Å⁻³
S = 1.06	Δρ_min = −0.16 e Å⁻³
2497 reflections	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
172 parameters	Extinction coefficient: 0.036 (6)
Primary atom site location: structure-invariant direct methods	Absolute structure: Flack (1983), 1028 Friedel pairs
Secondary atom site location: difference Fourier map	Flack parameter: 0.0 (2)
Hydrogen site location: inferred from neighbouring sites

Crystal data top

C₃₂H₂₈N₂·CH₂Cl₂	V = 1411.3 (7) Å³
M_r = 525.49	Z = 2
Orthorhombic, P2₁2₁2	Mo Kα
a = 8.550 (2) Å	µ = 0.25 mm⁻¹
b = 20.706 (6) Å	T = 298 K
c = 7.972 (3) Å	0.40 × 0.24 × 0.20 mm

Data collection top

Siemens P4 diffractometer	1428 reflections with I > 2σ(I)
Absorption correction: gaussian (XSCANS; Siemens, 1996)	R_int = 0.060
T_min = 0.933, T_max = 0.954	3 standard reflections
6308 measured reflections	every 97 reflections
2497 independent reflections	intensity decay: 2.3%

Refinement top

R[F² > 2σ(F²)] = 0.060	H-atom parameters constrained
wR(F²) = 0.186	Δρ_max = 0.19 e Å⁻³
S = 1.06	Δρ_min = −0.16 e Å⁻³
2497 reflections	Absolute structure: Flack (1983), 1028 Friedel pairs
172 parameters	Flack parameter: 0.0 (2)

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
N1	0.8943 (5)	0.38124 (15)	1.0214 (4)	0.0789 (10)
C1	1.0000	0.5000	1.5231 (7)	0.0904 (19)
H1A	1.0000	0.5000	1.6398	0.108*
C2	0.9506 (5)	0.4463 (2)	1.4376 (5)	0.0800 (12)
H2A	0.9166	0.4102	1.4968	0.096*
C3	0.9508 (4)	0.44531 (18)	1.2633 (5)	0.0660 (10)
C4	1.0000	0.5000	1.1777 (7)	0.0682 (14)
H4A	1.0000	0.5000	1.0611	0.082*
C5	0.9004 (5)	0.38667 (18)	1.1771 (5)	0.0711 (10)
H5A	0.8711	0.3514	1.2420	0.085*
C6	0.8370 (5)	0.32020 (18)	0.9537 (5)	0.0747 (11)
H6A	0.8222	0.2897	1.0464	0.090*
C7	0.6791 (5)	0.3332 (2)	0.8717 (6)	0.0947 (14)
H7A	0.6077	0.3499	0.9539	0.142*
H7B	0.6383	0.2937	0.8262	0.142*
H7C	0.6918	0.3642	0.7832	0.142*
C8	0.9507 (5)	0.29178 (16)	0.8309 (5)	0.0646 (9)
C9	1.0643 (5)	0.32880 (18)	0.7563 (5)	0.0760 (11)
H9A	1.0740	0.3720	0.7868	0.091*
C10	1.1656 (6)	0.3034 (2)	0.6361 (6)	0.0924 (14)
H10A	1.2430	0.3295	0.5899	0.111*
C11	1.1527 (6)	0.2419 (2)	0.5865 (5)	0.0851 (12)
H11A	1.2184	0.2263	0.5028	0.102*
C12	1.0413 (5)	0.20049 (19)	0.6592 (5)	0.0751 (11)
C13	1.0297 (6)	0.1351 (2)	0.6116 (6)	0.0911 (13)
H13A	1.0960	0.1188	0.5293	0.109*
C14	0.9225 (6)	0.0957 (2)	0.6848 (7)	0.0973 (15)
H14A	0.9158	0.0527	0.6524	0.117*
C15	0.8233 (5)	0.1194 (2)	0.8073 (7)	0.0909 (14)
H15A	0.7514	0.0919	0.8578	0.109*
C16	0.8295 (5)	0.18255 (17)	0.8549 (6)	0.0749 (11)
H16A	0.7615	0.1975	0.9371	0.090*
C17	0.9380 (4)	0.22579 (17)	0.7812 (5)	0.0652 (9)
C18	0.5000	0.5000	0.8916 (9)	0.123 (3)
H18A	0.4641	0.5349	0.9629	0.148*
Cl1	0.6505 (3)	0.52641 (11)	0.7706 (3)	0.1852 (10)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
N1	0.102 (3)	0.0685 (19)	0.067 (2)	−0.0018 (18)	0.003 (2)	0.0003 (16)
C1	0.099 (5)	0.115 (5)	0.057 (3)	0.000 (4)	0.000	0.000
C2	0.084 (3)	0.090 (3)	0.066 (2)	0.004 (3)	0.008 (2)	0.008 (2)
C3	0.062 (2)	0.076 (2)	0.060 (2)	0.0110 (19)	0.0047 (19)	0.0017 (19)
C4	0.073 (3)	0.075 (3)	0.056 (3)	0.015 (3)	0.000	0.000
C5	0.073 (2)	0.070 (2)	0.070 (3)	0.008 (2)	0.007 (2)	0.008 (2)
C6	0.085 (3)	0.070 (2)	0.069 (2)	−0.001 (2)	0.003 (2)	0.0066 (19)
C7	0.080 (3)	0.099 (3)	0.105 (3)	0.016 (3)	0.008 (3)	0.000 (3)
C8	0.069 (2)	0.064 (2)	0.060 (2)	0.0002 (18)	0.003 (2)	0.0087 (17)
C9	0.085 (3)	0.072 (2)	0.071 (2)	−0.006 (2)	0.005 (2)	0.009 (2)
C10	0.091 (3)	0.100 (3)	0.086 (3)	−0.005 (3)	0.026 (3)	0.022 (3)
C11	0.082 (3)	0.102 (3)	0.072 (3)	0.013 (3)	0.011 (2)	0.003 (2)
C12	0.071 (2)	0.081 (2)	0.073 (2)	0.010 (2)	−0.014 (2)	−0.004 (2)
C13	0.089 (3)	0.090 (3)	0.095 (3)	0.020 (3)	−0.019 (3)	−0.019 (3)
C14	0.097 (3)	0.076 (3)	0.120 (4)	0.012 (3)	−0.030 (4)	−0.010 (3)
C15	0.078 (3)	0.075 (3)	0.120 (4)	−0.005 (2)	−0.024 (3)	0.007 (3)
C16	0.066 (2)	0.072 (2)	0.087 (3)	−0.004 (2)	−0.004 (2)	0.002 (2)
C17	0.059 (2)	0.069 (2)	0.068 (2)	0.0022 (18)	−0.007 (2)	0.0072 (18)
C18	0.192 (10)	0.094 (5)	0.084 (4)	−0.003 (5)	0.000	0.000
Cl1	0.1454 (16)	0.208 (2)	0.202 (2)	−0.0442 (14)	0.0100 (17)	0.0547 (16)

Geometric parameters (Å, °) top

N1—C5	1.248 (5)	C9—C10	1.395 (6)
N1—C6	1.459 (5)	C9—H9A	0.9300
C1—C2	1.371 (5)	C10—C11	1.338 (6)
C1—C2ⁱ	1.371 (5)	C10—H10A	0.9300
C1—H1A	0.9300	C11—C12	1.407 (6)
C2—C3	1.390 (5)	C11—H11A	0.9300
C2—H2A	0.9300	C12—C13	1.410 (6)
C3—C4	1.387 (4)	C12—C17	1.414 (5)
C3—C5	1.460 (5)	C13—C14	1.359 (7)
C4—C3ⁱ	1.387 (4)	C13—H13A	0.9300
C4—H4A	0.9300	C14—C15	1.384 (7)
C5—H5A	0.9300	C14—H14A	0.9300
C6—C8	1.500 (5)	C15—C16	1.363 (5)
C6—C7	1.524 (6)	C15—H15A	0.9300
C6—H6A	0.9800	C16—C17	1.416 (5)
C7—H7A	0.9600	C16—H16A	0.9300
C7—H7B	0.9600	C18—Cl1ⁱⁱ	1.699 (5)
C7—H7C	0.9600	C18—Cl1	1.699 (5)
C8—C9	1.373 (5)	C18—H18A	0.9698
C8—C17	1.427 (5)

C5—N1—C6	117.4 (3)	C8—C9—C10	121.8 (4)
C2—C1—C2ⁱ	120.4 (6)	C8—C9—H9A	119.1
C2—C1—H1A	119.8	C10—C9—H9A	119.1
C2ⁱ—C1—H1A	119.8	C11—C10—C9	120.7 (4)
C1—C2—C3	120.6 (4)	C11—C10—H10A	119.7
C1—C2—H2A	119.7	C9—C10—H10A	119.7
C3—C2—H2A	119.7	C10—C11—C12	121.0 (4)
C4—C3—C2	118.7 (4)	C10—C11—H11A	119.5
C4—C3—C5	122.5 (4)	C12—C11—H11A	119.5
C2—C3—C5	118.8 (4)	C11—C12—C13	121.5 (4)
C3—C4—C3ⁱ	121.1 (5)	C11—C12—C17	118.7 (4)
C3—C4—H4A	119.4	C13—C12—C17	119.8 (4)
C3ⁱ—C4—H4A	119.4	C14—C13—C12	120.5 (5)
N1—C5—C3	123.7 (4)	C14—C13—H13A	119.7
N1—C5—H5A	118.1	C12—C13—H13A	119.7
C3—C5—H5A	118.1	C13—C14—C15	120.3 (4)
N1—C6—C8	111.3 (3)	C13—C14—H14A	119.9
N1—C6—C7	107.6 (3)	C15—C14—H14A	119.9
C8—C6—C7	111.3 (3)	C16—C15—C14	120.8 (5)
N1—C6—H6A	108.8	C16—C15—H15A	119.6
C8—C6—H6A	108.8	C14—C15—H15A	119.6
C7—C6—H6A	108.8	C15—C16—C17	121.1 (4)
C6—C7—H7A	109.5	C15—C16—H16A	119.4
C6—C7—H7B	109.5	C17—C16—H16A	119.4
H7A—C7—H7B	109.5	C12—C17—C16	117.4 (4)
C6—C7—H7C	109.5	C12—C17—C8	119.9 (3)
H7A—C7—H7C	109.5	C16—C17—C8	122.7 (4)
H7B—C7—H7C	109.5	Cl1ⁱⁱ—C18—Cl1	110.8 (4)
C9—C8—C17	117.9 (4)	Cl1ⁱⁱ—C18—H18A	109.4
C9—C8—C6	121.5 (3)	Cl1—C18—H18A	109.4
C17—C8—C6	120.5 (3)

C2ⁱ—C1—C2—C3	0.4 (3)	C10—C11—C12—C13	−178.1 (4)
C1—C2—C3—C4	−0.9 (6)	C10—C11—C12—C17	2.7 (6)
C1—C2—C3—C5	178.7 (3)	C11—C12—C13—C14	179.2 (4)
C2—C3—C4—C3ⁱ	0.4 (3)	C17—C12—C13—C14	−1.6 (6)
C5—C3—C4—C3ⁱ	−179.1 (4)	C12—C13—C14—C15	0.0 (7)
C6—N1—C5—C3	−178.2 (4)	C13—C14—C15—C16	1.0 (7)
C4—C3—C5—N1	−1.5 (6)	C14—C15—C16—C17	−0.3 (6)
C2—C3—C5—N1	179.0 (4)	C11—C12—C17—C16	−178.6 (4)
C5—N1—C6—C8	−126.4 (4)	C13—C12—C17—C16	2.2 (5)
C5—N1—C6—C7	111.4 (4)	C11—C12—C17—C8	−1.5 (5)
N1—C6—C8—C9	−19.0 (5)	C13—C12—C17—C8	179.3 (4)
C7—C6—C8—C9	101.1 (4)	C15—C16—C17—C12	−1.3 (6)
N1—C6—C8—C17	164.5 (3)	C15—C16—C17—C8	−178.3 (4)
C7—C6—C8—C17	−75.4 (4)	C9—C8—C17—C12	0.3 (5)
C17—C8—C9—C10	−0.3 (6)	C6—C8—C17—C12	177.0 (3)
C6—C8—C9—C10	−176.9 (4)	C9—C8—C17—C16	177.2 (3)
C8—C9—C10—C11	1.5 (7)	C6—C8—C17—C16	−6.1 (5)
C9—C10—C11—C12	−2.7 (7)

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

supplementary materials

1,3-Bis{(+)-(S)-[1-(1-naphthyl)ethyl]iminomethyl}benzene dichloromethane solvate

A. Espinosa Leija, G. Hernández, S. Cruz, S. Bernès and R. Gutiérrez

	Fig. 1. Molecular structure of the title compound, with 30% probability level displacement ellipsoids for non-H atoms. Non-labeled atoms are generated through the symmetry operation 2 - x, 1 - y, z.
	Fig. 2. A part of the crystal structure of the title compound along [100], showing the lattice solvent molecules with a space-filling representation.