(IUCr) Crystallography Journals Online

Abstract top

The molecule of the title compound, C₂₈H₄₂N₆, has site symmetry $\overline{1}$ with the centroid of the piperazine ring located on an inversion center. The piperazine ring adopts a chair conformation. The benzene ring and propylpiperazine are on opposite sides of the C=N bond, showing an E configuration.

Comment top

Schiff bases and their metal complexes have been of great interest for many years due to their fascinating structural features, attactive properties and potential applications in many fields (Basak et al., 2008; Jiang et al., 2008; Xu et al., 2008). While N,N'- disubstituted piperazines derivatives are antifilarial, antiamoebic and spermicidal agents (Yogavel et al., 2003), therefore, studies on Schiff bases and their complexes derived from N,N'- disubstituted piperazines are of importance. As part of our work, the title compound,(I), a new tetradentate Schiff base ligand, are synthesized in our group and its crystal structure is reported here.

The molecular structure of (I) with atom-numbering scheme is shown in Fig.1. The bond length of C1—N2 (1.278 (7) Å) is equal to that of C1A—N2A, which is much shorter than the C—N single bond length (1.47 - 1.50 Å) and comparable with the reported values (Yogavel et al., 2003; Thirumurugan et al., 1998), indicating that the C—N bonds are double bonds. Two phenyl rings (C2—C7 and C2A—C7A) in (I) are perfectly parellel to each other. As for the piperazine moiety, the four atoms C13—C14—C13A—C14A are coplanar, and N3 atom or N3A atom lies above or below the mean plan by 0.6510 or -0.6510 Å. Furthermore, the plan makes dihedral angles of 129 ° with ring C13—N3—C14A or ring C13A—N3A—C14, indicating that the two rings are parallel and that the piperazine ring has a chair conformation just like other Schiff bases containing piperazine ring (Paital et al., 2009; Thirumurugan et al., 1998).

1,4-Bis{3-[4-(dimethylamino)benzylideneamino]propyl}piperazine top

Crystal data top

C₂₈H₄₂N₆	F(000) = 504
M_r = 462.68	D_x = 1.118 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 683 reflections
a = 17.599 (2) Å	θ = 2.4–49.5°
b = 6.4146 (12) Å	µ = 0.07 mm⁻¹
c = 12.6643 (18) Å	T = 298 K
β = 105.921 (3)°	Platelet, yellow
V = 1374.8 (4) Å³	0.15 × 0.09 × 0.07 mm
Z = 2

Data collection top

Bruker SMART CCD area-detector diffractometer	961 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.088
graphite	θ_max = 25.0°, θ_min = 2.4°
φ and ω scans	h = −20→20
6788 measured reflections	k = −7→5
2416 independent reflections	l = −15→14

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.095	H-atom parameters constrained
wR(F²) = 0.298	w = 1/[σ²(F_o²) + (0.0892P)²] where P = (F_o² + 2F_c²)/3
S = 1.34	(Δ/σ)_max = 0.004
2416 reflections	Δρ_max = 0.24 e Å⁻³
155 parameters	Δρ_min = −0.17 e Å⁻³
0 restraints	Extinction correction: SHELXTL (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.015 (5)

Crystal data top

C₂₈H₄₂N₆	V = 1374.8 (4) Å³
M_r = 462.68	Z = 2
Monoclinic, P2₁/c	Mo Kα radiation
a = 17.599 (2) Å	µ = 0.07 mm⁻¹
b = 6.4146 (12) Å	T = 298 K
c = 12.6643 (18) Å	0.15 × 0.09 × 0.07 mm
β = 105.921 (3)°

Data collection top

Bruker SMART CCD area-detector diffractometer	961 reflections with I > 2σ(I)
6788 measured reflections	R_int = 0.088
2416 independent reflections	θ_max = 25.0°

Refinement top

R[F² > 2σ(F²)] = 0.095	H-atom parameters constrained
wR(F²) = 0.298	Δρ_max = 0.24 e Å⁻³
S = 1.34	Δρ_min = −0.17 e Å⁻³
2416 reflections	Absolute structure: ?
155 parameters	Flack parameter: ?
0 restraints	Rogers parameter: ?

Special details top

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.

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 (Å²) top

	x	y	z	U_iso*/U_eq
N1	0.9158 (3)	−0.7316 (8)	1.1684 (4)	0.0687 (16)
N2	0.7447 (3)	0.0908 (8)	0.9057 (5)	0.0667 (15)
N3	0.5629 (3)	0.4652 (7)	0.5991 (4)	0.0590 (14)
C1	0.7396 (3)	−0.0090 (10)	0.9908 (6)	0.0625 (17)
H1	0.7045	0.0408	1.0280	0.075*
C2	0.7852 (3)	−0.1960 (9)	1.0339 (5)	0.0541 (16)
C3	0.8387 (3)	−0.2867 (10)	0.9837 (5)	0.0598 (17)
H3	0.8455	−0.2295	0.9194	0.072*
C4	0.8822 (3)	−0.4629 (9)	1.0298 (5)	0.0563 (16)
H4	0.9183	−0.5194	0.9961	0.068*
C5	0.8728 (3)	−0.5567 (9)	1.1258 (5)	0.0539 (16)
C6	0.8190 (3)	−0.4665 (9)	1.1741 (5)	0.0580 (16)
H6	0.8113	−0.5255	1.2375	0.070*
C7	0.7766 (3)	−0.2905 (10)	1.1299 (5)	0.0672 (18)
H7	0.7414	−0.2333	1.1649	0.081*
C8	0.9031 (4)	−0.8320 (10)	1.2662 (5)	0.083 (2)
H8A	0.9375	−0.9505	1.2856	0.124*
H8B	0.8492	−0.8767	1.2510	0.124*
H8C	0.9145	−0.7346	1.3260	0.124*
C9	0.9638 (4)	−0.8399 (10)	1.1115 (6)	0.083 (2)
H9A	0.9889	−0.9563	1.1548	0.125*
H9B	1.0033	−0.7471	1.0993	0.125*
H9C	0.9312	−0.8890	1.0422	0.125*
C10	0.6968 (4)	0.2755 (10)	0.8724 (5)	0.0704 (19)
H10A	0.7309	0.3962	0.8784	0.084*
H10B	0.6636	0.2962	0.9214	0.084*
C11	0.6451 (4)	0.2571 (9)	0.7554 (5)	0.0665 (18)
H11A	0.6095	0.1398	0.7500	0.080*
H11B	0.6781	0.2311	0.7067	0.080*
C12	0.5971 (3)	0.4555 (9)	0.7193 (5)	0.0637 (18)
H12A	0.5548	0.4618	0.7547	0.076*
H12B	0.6309	0.5758	0.7431	0.076*
C13	0.5345 (4)	0.6762 (9)	0.5644 (5)	0.0710 (19)
H13A	0.5778	0.7745	0.5873	0.085*
H13B	0.4940	0.7152	0.5995	0.085*
C14	0.5005 (4)	0.6860 (10)	0.4399 (5)	0.0678 (18)
H14A	0.4803	0.8251	0.4189	0.081*
H14B	0.5422	0.6586	0.4051	0.081*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
N1	0.081 (4)	0.071 (4)	0.055 (4)	0.017 (3)	0.020 (3)	0.013 (3)
N2	0.061 (3)	0.074 (4)	0.063 (4)	0.015 (3)	0.013 (3)	0.011 (3)
N3	0.054 (3)	0.060 (3)	0.063 (4)	0.007 (3)	0.015 (3)	0.012 (3)
C1	0.057 (4)	0.069 (4)	0.067 (5)	0.005 (3)	0.026 (3)	−0.007 (4)
C2	0.052 (3)	0.062 (4)	0.049 (4)	0.004 (3)	0.015 (3)	0.004 (3)
C3	0.062 (4)	0.067 (4)	0.052 (4)	−0.007 (3)	0.017 (3)	0.003 (3)
C4	0.057 (4)	0.062 (4)	0.052 (4)	0.003 (3)	0.019 (3)	0.001 (3)
C5	0.059 (4)	0.057 (4)	0.043 (4)	−0.007 (3)	0.009 (3)	0.003 (3)
C6	0.070 (4)	0.065 (4)	0.043 (4)	−0.005 (3)	0.023 (3)	0.000 (3)
C7	0.065 (4)	0.073 (5)	0.072 (5)	−0.002 (4)	0.033 (4)	0.003 (4)
C8	0.098 (5)	0.079 (5)	0.067 (5)	0.003 (4)	0.014 (4)	0.017 (4)
C9	0.097 (5)	0.069 (5)	0.086 (6)	0.013 (4)	0.027 (4)	0.004 (4)
C10	0.061 (4)	0.070 (5)	0.075 (5)	0.006 (3)	0.012 (4)	0.010 (4)
C11	0.069 (4)	0.067 (4)	0.068 (5)	0.012 (3)	0.026 (4)	0.015 (4)
C12	0.062 (4)	0.068 (4)	0.063 (5)	0.006 (3)	0.020 (3)	0.008 (3)
C13	0.075 (4)	0.063 (4)	0.072 (5)	0.013 (4)	0.017 (4)	0.013 (3)
C14	0.068 (4)	0.063 (4)	0.073 (5)	0.003 (4)	0.021 (4)	0.021 (4)

Geometric parameters (Å, °) top

N1—C5	1.378 (7)	C8—H8A	0.9600
N1—C9	1.432 (7)	C8—H8B	0.9600
N1—C8	1.466 (7)	C8—H8C	0.9600
N2—C1	1.278 (7)	C9—H9A	0.9600
N2—C10	1.448 (7)	C9—H9B	0.9600
N3—C13	1.468 (7)	C9—H9C	0.9600
N3—C14ⁱ	1.459 (7)	C10—C11	1.516 (8)
N3—C12	1.477 (7)	C10—H10A	0.9700
C1—C2	1.462 (8)	C10—H10B	0.9700
C1—H1	0.9300	C11—C12	1.527 (8)
C2—C7	1.404 (7)	C11—H11A	0.9700
C2—C3	1.400 (7)	C11—H11B	0.9700
C3—C4	1.399 (8)	C12—H12A	0.9700
C3—H3	0.9300	C12—H12B	0.9700
C4—C5	1.407 (7)	C13—C14	1.527 (8)
C4—H4	0.9300	C13—H13A	0.9700
C5—C6	1.387 (8)	C13—H13B	0.9700
C6—C7	1.384 (8)	C14—N3ⁱ	1.459 (7)
C6—H6	0.9300	C14—H14A	0.9700
C7—H7	0.9300	C14—H14B	0.9700

C5—N1—C9	122.3 (5)	N1—C9—H9B	109.5
C5—N1—C8	119.7 (5)	H9A—C9—H9B	109.5
C9—N1—C8	117.3 (5)	N1—C9—H9C	109.5
C1—N2—C10	119.0 (5)	H9A—C9—H9C	109.5
C13—N3—C14ⁱ	110.2 (5)	H9B—C9—H9C	109.5
C13—N3—C12	110.9 (5)	N2—C10—C11	111.5 (5)
C14ⁱ—N3—C12	112.2 (5)	N2—C10—H10A	109.3
N2—C1—C2	124.6 (6)	C11—C10—H10A	109.3
N2—C1—H1	117.7	N2—C10—H10B	109.3
C2—C1—H1	117.7	C11—C10—H10B	109.3
C7—C2—C3	117.4 (6)	H10A—C10—H10B	108.0
C7—C2—C1	120.0 (6)	C10—C11—C12	111.2 (5)
C3—C2—C1	122.7 (6)	C10—C11—H11A	109.4
C4—C3—C2	120.4 (6)	C12—C11—H11A	109.4
C4—C3—H3	119.8	C10—C11—H11B	109.4
C2—C3—H3	119.8	C12—C11—H11B	109.4
C3—C4—C5	121.7 (6)	H11A—C11—H11B	108.0
C3—C4—H4	119.2	N3—C12—C11	112.3 (5)
C5—C4—H4	119.2	N3—C12—H12A	109.1
N1—C5—C6	122.3 (6)	C11—C12—H12A	109.1
N1—C5—C4	120.3 (6)	N3—C12—H12B	109.1
C6—C5—C4	117.4 (6)	C11—C12—H12B	109.1
C7—C6—C5	121.3 (6)	H12A—C12—H12B	107.9
C7—C6—H6	119.3	N3—C13—C14	110.6 (5)
C5—C6—H6	119.3	N3—C13—H13A	109.5
C6—C7—C2	121.9 (6)	C14—C13—H13A	109.5
C6—C7—H7	119.1	N3—C13—H13B	109.5
C2—C7—H7	119.1	C14—C13—H13B	109.5
N1—C8—H8A	109.5	H13A—C13—H13B	108.1
N1—C8—H8B	109.5	N3ⁱ—C14—C13	111.6 (5)
H8A—C8—H8B	109.5	N3ⁱ—C14—H14A	109.3
N1—C8—H8C	109.5	C13—C14—H14A	109.3
H8A—C8—H8C	109.5	N3ⁱ—C14—H14B	109.3
H8B—C8—H8C	109.5	C13—C14—H14B	109.3
N1—C9—H9A	109.5	H14A—C14—H14B	108.0

Symmetry codes: (i) −x+1, −y+1, −z+1.

supplementary materials

1,4-Bis{3-[4-(dimethylamino)benzylideneamino]propyl}piperazine

R.-B. Xu, X.-Y. Xu, D.-Q. Wang, X.-J. Yang and S. Li