4,4′-Dimethoxy-2,2′-[1,1′-(propane-1,3-diyldinitrilo)diethylidyne]diphenol

Fun, H.-K.; Kia, R.

doi:10.1107/S1600536808023738

organic compounds

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ISSN: 2056-9890

Volume 64| Part 9| September 2008| Pages o1657-o1658

doi:10.1107/S1600536808023738

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4,4′-Dimethoxy-2,2′-[1,1′-(propane-1,3-diyldinitrilo)diethylidyne]diphenol

Hoong-Kun Fun ^a ^* and Reza Kia ^a ‡

^aX-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia
^*Correspondence e-mail: hkfun@usm.my

(Received 21 July 2008; accepted 27 July 2008; online 6 August 2008)

In the crystal structure, the title Schiff base compound, C₂₁H₂₆N₂O₄, has twofold rotation symmetry. The imino group is coplanar with the aromatic ring. An intramolecular O—H⋯N hydrogen bond forms a six- membered ring, producing an S(6) ring motif. The two benzene rings are almost perpendicular to each other, making a dihedral angle of 85.00 (2)°. The methoxy group is approximately coplanar with the benzene ring, with a C—O—C—C torsion angle of 2.34 (12)°. Neighbouring molecules are linked together by weak intermolecular C—H⋯O hydrogen bonds and a C—H⋯π interaction, forming a sheet parallel to the ab plane. The molecules also adopt a zigzag arrangement along the c axis.

Related literature

For bond-length data, see: Allen et al. (1987 ). For hydrogen-bond motifs, see: Bernstein et al. (1995 ). For information on Schiff base ligands and complexes, and their applications, see, for example: Fun, Kargar & Kia (2008 ); Fun, Kia & Kargar (2008 ); Fun, Mirkhani et al. (2008a ,b ); Calligaris & Randaccio (1987 ); Casellato & Vigato (1977 ); Kia, Mirkhani, Kalman & Deak (2007 ); Kia, Mirkhani, Harkema & van Hummel (2007 ); Pal et al. (2005 ); Reglinski et al. (2004 ); Hou et al. (2001 ); Ren et al. (2002 ).

Experimental

Crystal data

C₂₁H₂₆N₂O₄
M_r = 370.44
Monoclinic, C 2/c
a = 12.8042 (2) Å
b = 5.0508 (1) Å
c = 28.6019 (6) Å
β = 93.109 (2)°
V = 1847.00 (6) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 100.0 (1) K
0.47 × 0.44 × 0.29 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ) T_min = 0.884, T_max = 0.974
34801 measured reflections
5229 independent reflections
4304 reflections with I > 2σ(I)
R_int = 0.031

Refinement

R[F² > 2σ(F²)] = 0.057
wR(F²) = 0.148
S = 1.11
5229 reflections
125 parameters
H-atom parameters constrained
Δρ_max = 0.45 e Å⁻³
Δρ_min = −0.28 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1O1⋯N1	0.97	1.62	2.5241 (10)	153
C11—H11A⋯O1ⁱ	0.96	2.53	3.4448 (12)	160
C11—H11B⋯O1ⁱⁱ	0.96	2.53	3.4360 (12)	157
C10—H10C⋯Cg1ⁱⁱⁱ	0.96	2.68	3.5224 (10)	147
Symmetry codes: (i) $[x-{\script{1\over 2}}, y-{\script{1\over 2}}, z]$ ; (ii) $[x-{\script{1\over 2}}, y+{\script{1\over 2}}, z]$ ; (iii) x, y+1, z. Cg1 is the centroid of the C1–C6 benzene ring.

Data collection: APEX2 (Bruker, 2005); cell refinement: APEX2; data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL, PLATON (Spek, 2003 ) and PARST95 (Nardelli, 1995 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808023738/is2318sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808023738/is2318Isup2.hkl

checkCIF report

Comment top

The condensation of primary amines with carbonyl compounds yields Schiff base (Casellato & Vigato, 1977) that are still now regarded as one of the most potential group of chelators for facile preparations of metallo-organic hybrid materials. In the past two decades, the synthesis, structure and properties of Schiff base complexes have stimulated much interest for their noteworthy contributions in single molecule-based magnetism, materials science, catalysis of many reactions like carbonylation, hydroformylation, reduction, oxidation, epoxidation and hydrolysis, etc (Kia, Mirkhani, Kalman & Deak, 2007; Kia, Mirkhani, Harkema & van Hummel, 2007; Pal et al., 2005; Reglinski et al., 2004; Hou et al., 2001; Ren et al., 2002). This is due to the fact that Schiff bases offer opportunities for inducing substrate chirality, tuning the metal-centered electronic factor and enhancing the solubility and stability of either homogeneous or heterogeneous catalysts. Only a relatively small number of free Schiff base ligands have been characterized (Calligaris & Randaccio, 1987). As an extension of our work (Fun, Kargar & Kia, 2008; Fun, Kia & Kargar, 2008; Fun et al., 2008a,b) on the structural characterization of Schiff base compounds, the title compound (I), is reported here.

The molecule of the title compound, (I), has a crystallographic twofold rotation symmetry (Fig. 1). The bond lengths and angles are within normal ranges (Allen et al.,1987). The asymmetric unit of the compound is composed of one-half of the molecule. An intramolecular O—H···N hydrogen bond forms a six-membered ring, producing an S(6) ring motif (Bernstein et al. 1995). The two benzene rings are almost perpendicular to each other with a dihedral angle of 85.00 (2)°. The methoxy group is coplanar with the benzene ring, with the C10–O2–C4–C3 torsion angle of 2.34 (12)°. In the crystal structure neighbouring molecules are linked together by weak intermolecular C—H···O hydrogen bonds and a C—H···π interaction to form a sheet parallel to the ab plane (Fig. 2). These molecules also adopt a zigzag arrangement along the c axis (Fig. 3).

Related literature top

For bond-length data, see: Allen et al. (1987). For hydrogen-bond motifs, see: Bernstein et al. (1995). For information on Schiff base ligands and complexes, and their applications, see, for example: Fun, Kargar & Kia (2008); Fun, Kia & Kargar (2008); Fun, Mirkhani et al. (2008a,b); Calligaris & Randaccio (1987); Casellato & Vigato (1977); Kia, Mirkhani, Kalman & Deak (2007); Kia, Mirkhani, Harkema & van Hummel (2007); Pal et al. (2005); Reglinski et al. (2004); Hou et al. (2001); Ren et al. (2002). Cg1 is centroid of the C1–C6 benzene ring.

Experimental top

The synthetic method has been described earlier (Reglinski et al., 2004). Single crystals suitable for X-ray diffraction were obtained by evaporation of an ethanol solution at room temperature.

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: APEX2 (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008), PLATON (Spek, 2003) and PARST95 (Nardelli, 1995).

Figures top

	Fig. 1. The molecular structure of (I) with atom labels and 50% probability ellipsoids for non-H atoms. The suffix A corresponds to symmetry code (-x + 1, y, -z + 1/2).
	Fig. 2. The crystal packing, showing stacking of molecules down the b axis. Intramolecular and intermolecular interactions are shown as dashed lines.
	Fig. 3. The crystal packing, showing zigzag arrangement of molecules along the c axis.

4,4'-Dimethoxy-2,2'-[1,1'-(propane-1,3-diyldinitrilo)diethylidyne]diphenol top

Crystal data top

C₂₁H₂₆N₂O₄	F(000) = 792
M_r = 370.44	D_x = 1.332 Mg m⁻³
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 9900 reflections
a = 12.8042 (2) Å	θ = 2.9–38.4°
b = 5.0508 (1) Å	µ = 0.09 mm⁻¹
c = 28.6019 (6) Å	T = 100 K
β = 93.109 (2)°	Block, yellow
V = 1847.00 (6) Å³	0.47 × 0.44 × 0.29 mm
Z = 4

Data collection top

Bruker SMART APEXII CCD area-detector diffractometer	5229 independent reflections
Radiation source: fine-focus sealed tube	4304 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.031
ϕ and ω scans	θ_max = 38.8°, θ_min = 2.9°
Absorption correction: multi-scan (SADABS; Bruker, 2005)	h = −22→18
T_min = 0.884, T_max = 0.974	k = −8→8
34801 measured reflections	l = −48→50

Refinement top

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)] = 0.057	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.148	H-atom parameters constrained
S = 1.11	w = 1/[σ²(F_o²) + (0.0571P)² + 1.5152P] where P = (F_o² + 2F_c²)/3
5229 reflections	(Δ/σ)_max < 0.001
125 parameters	Δρ_max = 0.45 e Å⁻³
0 restraints	Δρ_min = −0.28 e Å⁻³

Crystal data top

C₂₁H₂₆N₂O₄	V = 1847.00 (6) Å³
M_r = 370.44	Z = 4
Monoclinic, C2/c	Mo Kα radiation
a = 12.8042 (2) Å	µ = 0.09 mm⁻¹
b = 5.0508 (1) Å	T = 100 K
c = 28.6019 (6) Å	0.47 × 0.44 × 0.29 mm
β = 93.109 (2)°

Data collection top

Bruker SMART APEXII CCD area-detector diffractometer	5229 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2005)	4304 reflections with I > 2σ(I)
T_min = 0.884, T_max = 0.974	R_int = 0.031
34801 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.057	0 restraints
wR(F²) = 0.148	H-atom parameters constrained
S = 1.11	Δρ_max = 0.45 e Å⁻³
5229 reflections	Δρ_min = −0.28 e Å⁻³
125 parameters

Special details top

Experimental. The low-temperature data was collected with the Oxford Cyrosystem Cobra 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.

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

	x	y	z	U_iso*/U_eq
O1	0.59948 (5)	0.57780 (14)	0.14698 (2)	0.01790 (13)
H1O1	0.5565	0.4795	0.1680	0.027*
O2	0.32409 (5)	1.27531 (14)	0.05669 (2)	0.01928 (13)
N1	0.44774 (6)	0.41178 (14)	0.19154 (2)	0.01406 (12)
C1	0.53083 (6)	0.74582 (16)	0.12471 (3)	0.01383 (13)
C2	0.56814 (6)	0.91899 (18)	0.09166 (3)	0.01619 (14)
H2A	0.6385	0.9140	0.0851	0.019*
C3	0.50202 (7)	1.09968 (17)	0.06815 (3)	0.01633 (14)
H3A	0.5281	1.2150	0.0463	0.020*
C4	0.39649 (6)	1.10628 (16)	0.07764 (3)	0.01411 (13)
C5	0.35797 (6)	0.93301 (16)	0.11033 (3)	0.01378 (13)
H5A	0.2873	0.9380	0.1162	0.017*
C6	0.42331 (6)	0.75110 (15)	0.13460 (3)	0.01242 (13)
C7	0.38248 (6)	0.57157 (16)	0.17015 (3)	0.01281 (13)
C8	0.41119 (7)	0.23770 (17)	0.22797 (3)	0.01519 (14)
H8A	0.3572	0.1216	0.2145	0.018*
H8B	0.3807	0.3436	0.2520	0.018*
C9	0.5000	0.0715 (2)	0.2500	0.01590 (19)
H9	0.4651	−0.0665	0.2746	0.019*
C10	0.35993 (8)	1.44822 (19)	0.02170 (3)	0.01964 (16)
H10A	0.3025	1.5528	0.0090	0.029*
H10B	0.3883	1.3457	−0.0029	0.029*
H10C	0.4131	1.5628	0.0353	0.029*
C11	0.26922 (7)	0.57899 (19)	0.18136 (4)	0.01984 (16)
H11A	0.2370	0.4123	0.1733	0.030*
H11B	0.2343	0.7180	0.1638	0.030*
H11C	0.2639	0.6114	0.2142	0.030*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0124 (2)	0.0187 (3)	0.0228 (3)	0.0024 (2)	0.0023 (2)	0.0063 (2)
O2	0.0159 (3)	0.0187 (3)	0.0233 (3)	0.0031 (2)	0.0012 (2)	0.0076 (2)
N1	0.0143 (3)	0.0140 (3)	0.0139 (3)	−0.0006 (2)	0.0013 (2)	0.0014 (2)
C1	0.0119 (3)	0.0142 (3)	0.0155 (3)	0.0007 (2)	0.0015 (2)	0.0006 (2)
C2	0.0130 (3)	0.0177 (3)	0.0181 (3)	0.0002 (3)	0.0032 (2)	0.0024 (3)
C3	0.0160 (3)	0.0162 (3)	0.0170 (3)	−0.0008 (3)	0.0028 (3)	0.0027 (3)
C4	0.0137 (3)	0.0132 (3)	0.0154 (3)	0.0011 (2)	0.0008 (2)	0.0010 (2)
C5	0.0120 (3)	0.0139 (3)	0.0155 (3)	0.0005 (2)	0.0015 (2)	0.0005 (2)
C6	0.0114 (3)	0.0124 (3)	0.0135 (3)	0.0001 (2)	0.0018 (2)	−0.0001 (2)
C7	0.0122 (3)	0.0125 (3)	0.0137 (3)	−0.0008 (2)	0.0013 (2)	−0.0009 (2)
C8	0.0156 (3)	0.0152 (3)	0.0147 (3)	−0.0021 (2)	0.0011 (2)	0.0011 (3)
C9	0.0191 (5)	0.0125 (4)	0.0161 (5)	0.000	0.0000 (4)	0.000
C10	0.0229 (4)	0.0173 (3)	0.0186 (4)	0.0016 (3)	0.0005 (3)	0.0046 (3)
C11	0.0134 (3)	0.0215 (4)	0.0250 (4)	0.0007 (3)	0.0045 (3)	0.0063 (3)

Geometric parameters (Å, º) top

O1—C1	1.3556 (10)	C5—H5A	0.9300
O1—H1O1	0.9728	C6—C7	1.4787 (11)
O2—C4	1.3736 (10)	C7—C11	1.5025 (11)
O2—C10	1.4230 (11)	C8—C9	1.5221 (11)
N1—C7	1.2917 (11)	C8—H8A	0.9700
N1—C8	1.4597 (11)	C8—H8B	0.9700
C1—C2	1.3915 (12)	C9—C8ⁱ	1.5221 (11)
C1—C6	1.4208 (11)	C9—H9	1.1014
C2—C3	1.3928 (12)	C10—H10A	0.9600
C2—H2A	0.9300	C10—H10B	0.9600
C3—C4	1.3929 (12)	C10—H10C	0.9600
C3—H3A	0.9300	C11—H11A	0.9600
C4—C5	1.3906 (12)	C11—H11B	0.9600
C5—C6	1.4010 (11)	C11—H11C	0.9600

C1—O1—H1O1	103.6	C6—C7—C11	120.84 (7)
C4—O2—C10	116.90 (7)	N1—C8—C9	111.49 (6)
C7—N1—C8	119.36 (7)	N1—C8—H8A	109.3
O1—C1—C2	118.35 (7)	C9—C8—H8A	109.3
O1—C1—C6	121.93 (7)	N1—C8—H8B	109.3
C2—C1—C6	119.71 (7)	C9—C8—H8B	109.3
C1—C2—C3	121.18 (8)	H8A—C8—H8B	108.0
C1—C2—H2A	119.4	C8—C9—C8ⁱ	113.08 (10)
C3—C2—H2A	119.4	C8—C9—H9	107.1
C2—C3—C4	119.50 (8)	C8ⁱ—C9—H9	113.8
C2—C3—H3A	120.3	O2—C10—H10A	109.5
C4—C3—H3A	120.3	O2—C10—H10B	109.5
O2—C4—C5	115.40 (7)	H10A—C10—H10B	109.5
O2—C4—C3	124.67 (7)	O2—C10—H10C	109.5
C5—C4—C3	119.94 (7)	H10A—C10—H10C	109.5
C4—C5—C6	121.46 (7)	H10B—C10—H10C	109.5
C4—C5—H5A	119.3	C7—C11—H11A	109.5
C6—C5—H5A	119.3	C7—C11—H11B	109.5
C5—C6—C1	118.21 (7)	H11A—C11—H11B	109.5
C5—C6—C7	121.26 (7)	C7—C11—H11C	109.5
C1—C6—C7	120.52 (7)	H11A—C11—H11C	109.5
N1—C7—C6	117.71 (7)	H11B—C11—H11C	109.5
N1—C7—C11	121.44 (7)

O1—C1—C2—C3	−178.88 (8)	C2—C1—C6—C5	0.02 (12)
C6—C1—C2—C3	0.44 (13)	O1—C1—C6—C7	0.25 (12)
C1—C2—C3—C4	−0.42 (13)	C2—C1—C6—C7	−179.04 (8)
C10—O2—C4—C5	−177.58 (8)	C8—N1—C7—C6	177.96 (7)
C10—O2—C4—C3	2.34 (13)	C8—N1—C7—C11	−1.07 (12)
C2—C3—C4—O2	−179.99 (8)	C5—C6—C7—N1	−179.06 (8)
C2—C3—C4—C5	−0.07 (13)	C1—C6—C7—N1	−0.02 (11)
O2—C4—C5—C6	−179.53 (7)	C5—C6—C7—C11	−0.02 (12)
C3—C4—C5—C6	0.54 (13)	C1—C6—C7—C11	179.01 (8)
C4—C5—C6—C1	−0.51 (12)	C7—N1—C8—C9	−178.18 (7)
C4—C5—C6—C7	178.54 (7)	N1—C8—C9—C8ⁱ	58.96 (5)
O1—C1—C6—C5	179.32 (8)

Symmetry code: (i) −x+1, y, −z+1/2.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1O1···N1	0.97	1.62	2.5241 (10)	153
C11—H11A···O1ⁱⁱ	0.96	2.53	3.4448 (12)	160
C11—H11B···O1ⁱⁱⁱ	0.96	2.53	3.4360 (12)	157
C10—H10C···Cg1^iv	0.96	2.68	3.5224 (10)	147

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

Experimental details

Crystal data
Chemical formula	C₂₁H₂₆N₂O₄
M_r	370.44
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	100
a, b, c (Å)	12.8042 (2), 5.0508 (1), 28.6019 (6)
β (°)	93.109 (2)
V (Å³)	1847.00 (6)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.09
Crystal size (mm)	0.47 × 0.44 × 0.29

Data collection
Diffractometer	Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2005)
T_min, T_max	0.884, 0.974
No. of measured, independent and observed [I > 2σ(I)] reflections	34801, 5229, 4304
R_int	0.031
(sin θ/λ)_max (Å⁻¹)	0.882

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.057, 0.148, 1.11
No. of reflections	5229
No. of parameters	125
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.45, −0.28

Computer programs: APEX2 (Bruker, 2005), SAINT (Bruker, 2005), SHELXTL (Sheldrick, 2008), PLATON (Spek, 2003) and PARST95 (Nardelli, 1995).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1O1···N1	0.97	1.62	2.5241 (10)	153
C11—H11A···O1ⁱ	0.96	2.53	3.4448 (12)	160
C11—H11B···O1ⁱⁱ	0.96	2.53	3.4360 (12)	157
C10—H10C···Cg1ⁱⁱⁱ	0.96	2.68	3.5224 (10)	147

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

Footnotes

‡Additional correspondance author: e-mail: zsrkk@yahoo.com.

Acknowledgements

HKF and RK thank the Malaysian Government and Universiti Sains Malaysia for the Science Fund (grant No. 305/PFIZIK/613312). RK thanks Universiti Sains Malaysia for the award of a post-doctoral research fellowship.

References

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