6,6′-Dimeth­oxy-2,2′-[p-phenyl­ene­bis(nitrilo­methyl­idyne)]diphenol chloro­form disolvate

Al-Douh, M.H.; Osman, H.; Hamid, S.A.; Kia, R.; Fun, H.-K.

doi:10.1107/S1600536809007302

organic compounds

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ISSN: 2056-9890

Volume 65| Part 4| April 2009| Pages o680-o681

doi:10.1107/S1600536809007302

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6,6′-Dimethoxy-2,2′-[p-phenylenebis(nitrilomethylidyne)]diphenol chloroform disolvate

Mohammed H. Al-Douh,^a Hasnah Osman,^a ^*‡ Shafida Abd. Hamid,^b Reza Kia ^c and Hoong-Kun Fun ^c ^*

^aSchool of Chemical Sciences, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia, ^bKulliyyah of Science, International Islamic University Malaysia (IIUM), 25200 Kuantan, Pahang, Malaysia, and ^cX-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia
^*Correspondence e-mail: ohasnah@usm.my, hkfun@usm.my

(Received 25 February 2009; accepted 27 February 2009; online 6 March 2009)

The title compound, C₂₂H₂₀N₂O₄·2CHCl₃, a new Schiff base compound, lies across a crystallographic inversion centre. An intramolecular O—H⋯N hydrogen bond generates a six-membered ring, producing an S(6) ring motif. Intermolecular bifurcated C—H⋯O hydrogen bonds involving the two O atoms of the Schiff base ligand and the H atom of the chloroform solvent of crystallization, generate an R²₁(5) ring motif. The crystal structure is stabilized by intermolecular C—H⋯π and π–π interactions [centroid to centroid distance = 3.6158 (10) Å]. In the crystal structure, molecules are stacked down the c axis.

Related literature

For hydrogen-bond motifs, see: Bernstein et al. (1995 ). For the synthesis and applications of Schiff bases see, for example: Salem & Amer (1995 ); Teoh et al. (1997 ); Viswanathamurthi et al. (1998 ); Cohen et al. (1964 ); Kabak et al. (2000 ); Parra et al. (2007 ); Al-Douh et al. (2006 , 2007 , 2008 ); Liu et al. (2006 ); Shah et al. (2008 ). For the stability of the temperature controller used for the data collection, see: Cosier & Glazer (1986 ). For bond-length data, see: Allen et al. (1987 ).

Experimental

Crystal data

C₂₂H₂₀N₂O₄·2CHCl₃
M_r = 615.14
Monoclinic, P 2₁ /c
a = 10.4773 (2) Å
b = 21.3287 (5) Å
c = 6.2424 (2) Å
β = 105.669 (2)°
V = 1343.13 (6) Å³
Z = 2
Mo Kα radiation
μ = 0.67 mm⁻¹
T = 100 K
0.54 × 0.18 × 0.07 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ) T_min = 0.712, T_max = 0.958
10624 measured reflections
3069 independent reflections
2361 reflections with I > 2σ(I)
R_int = 0.033

Refinement

R[F² > 2σ(F²)] = 0.036
wR(F²) = 0.090
S = 1.03
3069 reflections
165 parameters
H-atom parameters constrained
Δρ_max = 0.35 e Å⁻³
Δρ_min = −0.25 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1⋯N1	0.84	1.84	2.584 (2)	147
C12—H12A⋯O1ⁱ	1.00	2.21	3.120 (3)	150
C12—H12A⋯O2ⁱ	1.00	2.30	3.121 (3)	139
C3—H3A⋯Cg1ⁱⁱ	0.95	2.73	3.5221 (19)	142
Symmetry codes: (i) x-1, y, z; (ii) $[x, -y-{\script{1\over 2}}, z-{\script{3\over 2}}]$ . Cg1 is the centroid of the C1–C6 benzene ring.

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT; 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 and PLATON (Spek, 2009).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809007302/at2731sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809007302/at2731Isup2.hkl

checkCIF report

Comment top

Bis-Schiff bases are a class of important compounds used as pharmaceutical, medicinal and industrial materials. Schiff bases have also been used extensively in coordination and inorganic chemistry. Salem and Amer used H₂O₂ to study the kinetics of the oxidation of a manganese complex with bis-Schiff base of salicyldehyde (Salem & Amer, 1995). Many of these Schiff bases were found to form suitable inner coordination spheres between tin atom with O and N atoms as quadridentate chelates (Teoh et al., 1997). Meanwhile, ruthenium complexes of bis-Schiff bases derived from o-vanillin and salicyldehyde were shown to exhibit dibasic tetradentate chelation (Viswanathamurthi et al., 1998). The intramolecular hydrogen bonds formed between O and N atoms in Schiff bases are responsible for the formation of these metal complexes (Cohen et al., 1964). Kabak et al. (2000) prepared the derivative of another isomer of the title compound and studied the photochromic conformational properties of this derivative, while Parra et al. (2007) examined the intercalation of another derivative of bis-Schiff bases with DNA by UV spectroscopy. Recently, we reported the crystal structure of the meta-isomer of the title compound (Al-Douh et al., 2007), while the single-crystal of the second isomer in the ortho-position was obtained and the data are consistent with the reported structure (Liu et al., 2006). The proton and carbon NMR spectroscopies of the title compound and its isomers were also studied (Al-Douh et al., 2008). Our group has been actively involved in synthesizing bis-Schiff bases and investigating their DNA binding ability using spectroscopic techniques employing calf thymus DNA (Shah et al., 2008). We have synthesized the third symmetric Schiff base by the condensation of o-vanillin with p-phenylenediamine and its X-ray crystal structure is presented here.

The title compound, (Fig. 1), lies across a crystallographic inversion centre [symmetry code of unlabelled atoms -x + 1, -y, -z + 2]. The bond lengths (Allen et al., 1987) and angles are within normal ranges. An intramolecular O—H···N hydrogen bond generates a six-membered ring, producing S(6) ring motif (Bernstein et al., 1995). Intermolecular bifurcated C—H···O hydrogen bonds involving the two oxygen atoms of the Schiff base ligand and the hydrogen atom of the chloroform solvent of crystallization generate a R²₁(5) ring motif. There are short contacts [C1–C9 = 3.267 (3) and C2–C9 = 3.399 (3) Å] which are shorter than the sum of the van der Waals radius of carbon atom. The crystal structure is stabilized by intermolecular C—H···π interaction (Cg1 is the centroid of the C1–C6 benzene ring) (Table 1) and intermolecular π-π interaction [Cg1···Cg2^{i, ii, iii, iv} = 3.6158 (10) Å; symmetry codes: (i) x, 1/2 - y, 1/2 + z (ii) x, y, -1 + z (iii) 1 - x, -y, 1 - z (iv) x, y, 1 + z, (Cg2 is the centroid of the benzene ring in the middle of the main molecule)]. In the crystal structure molecule are stacked down the c axis (Fig. 2).

Related literature top

For hydrogen-bond motifs, see: Bernstein et al. (1995). For the synthesis and applications of Schiff bases see, for example: Salem & Amer (1995); Teoh et al. (1997); Viswanathamurthi et al. (1998); Cohen et al. (1964); Kabak et al. (2000); Parra et al. (2007); Al-Douh et al. (2006, 2007, 2008); Liu et al. (2006); Shah et al. (2008). For the stability of the temperature controller used for the data collection, see: Cosier & Glazer (1986). For bond-length data, see: Allen et al. (1987). Cg1 is the centroid of the C1–C6 benzene ring.

Experimental top

The synthetic method has been described earlier (Al-Douh et al., 2006, 2007). Single crystals suitable for X-ray diffraction were obtained by slow evaporation of chloroform at room temperature.

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (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) and PLATON (Spek, 2009).

Figures top

	Fig. 1. The molecular structure of the title compound, showing 50% probability displacement ellipsoids and the atomic numbering [symmetry code of unlabelled atoms -x + 1, -y, -z + 2]. Intramolecular H bonds are drawn as dashed lines.
	Fig. 2. The crystal packing of the title compound, viewed down the c-axis showing stacking of molecules along the c-axis. Intermolecular hydrogen bonds are shown as dashed lines.

6,6'-Dimethoxy-2,2'-[p-phenylenebis(nitrilomethylidyne)]diphenol chloroform disolvates top

Crystal data top

C₂₂H₂₀N₂O₄·2CHCl₃	F(000) = 628
M_r = 615.14	D_x = 1.521 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 3653 reflections
a = 10.4773 (2) Å	θ = 2.8–29.6°
b = 21.3287 (5) Å	µ = 0.67 mm⁻¹
c = 6.2424 (2) Å	T = 100 K
β = 105.669 (2)°	Plate, yellow
V = 1343.13 (6) Å³	0.54 × 0.18 × 0.07 mm
Z = 2

Data collection top

Bruker SMART APEXII CCD area-detector diffractometer	3069 independent reflections
Radiation source: fine-focus sealed tube	2361 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.033
ϕ and ω scans	θ_max = 27.5°, θ_min = 2.0°
Absorption correction: multi-scan (SADABS; Bruker, 2005)	h = −13→13
T_min = 0.712, T_max = 0.958	k = −27→27
10624 measured reflections	l = −8→8

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)] = 0.036	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.090	H-atom parameters constrained
S = 1.03	w = 1/[σ²(F_o²) + (0.0405P)² + 0.6965P] where P = (F_o² + 2F_c²)/3
3069 reflections	(Δ/σ)_max < 0.001
165 parameters	Δρ_max = 0.35 e Å⁻³
0 restraints	Δρ_min = −0.25 e Å⁻³

Crystal data top

C₂₂H₂₀N₂O₄·2CHCl₃	V = 1343.13 (6) Å³
M_r = 615.14	Z = 2
Monoclinic, P2₁/c	Mo Kα radiation
a = 10.4773 (2) Å	µ = 0.67 mm⁻¹
b = 21.3287 (5) Å	T = 100 K
c = 6.2424 (2) Å	0.54 × 0.18 × 0.07 mm
β = 105.669 (2)°

Data collection top

Bruker SMART APEXII CCD area-detector diffractometer	3069 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2005)	2361 reflections with I > 2σ(I)
T_min = 0.712, T_max = 0.958	R_int = 0.033
10624 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.036	0 restraints
wR(F²) = 0.090	H-atom parameters constrained
S = 1.03	Δρ_max = 0.35 e Å⁻³
3069 reflections	Δρ_min = −0.25 e Å⁻³
165 parameters

Special details top

Experimental. The crystal was placed in the cold stream of an Oxford Cyrosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K.

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
Cl1	0.05508 (5)	0.10427 (3)	0.75969 (9)	0.03053 (15)
Cl2	0.09644 (5)	0.19372 (3)	0.43542 (10)	0.03061 (15)
Cl3	0.06333 (6)	0.06178 (3)	0.32245 (10)	0.03145 (15)
O1	0.71504 (12)	0.11003 (6)	0.4437 (2)	0.0159 (3)
H1	0.6880	0.0909	0.5406	0.024*
O2	0.76612 (13)	0.16921 (6)	0.1108 (2)	0.0167 (3)
N1	0.54474 (15)	0.06871 (7)	0.6416 (3)	0.0131 (3)
C1	0.61066 (18)	0.13631 (8)	0.2936 (3)	0.0126 (4)
C2	0.63590 (18)	0.16924 (8)	0.1137 (3)	0.0125 (4)
C3	0.53268 (19)	0.19797 (8)	−0.0409 (3)	0.0146 (4)
H3A	0.5499	0.2209	−0.1606	0.017*
C4	0.40308 (19)	0.19342 (8)	−0.0216 (3)	0.0159 (4)
H4A	0.3325	0.2128	−0.1295	0.019*
C5	0.37710 (18)	0.16110 (9)	0.1525 (3)	0.0153 (4)
H5A	0.2888	0.1583	0.1643	0.018*
C6	0.48096 (18)	0.13218 (8)	0.3132 (3)	0.0130 (4)
C7	0.45272 (19)	0.09798 (8)	0.4963 (3)	0.0147 (4)
H7A	0.3645	0.0971	0.5096	0.018*
C8	0.51663 (18)	0.03447 (8)	0.8182 (3)	0.0126 (4)
C9	0.62640 (18)	0.01408 (9)	0.9863 (3)	0.0153 (4)
H9A	0.7133	0.0235	0.9766	0.018*
C10	0.39007 (19)	0.01950 (9)	0.8339 (3)	0.0166 (4)
H10A	0.3146	0.0325	0.7202	0.020*
C11	0.7985 (2)	0.20505 (10)	−0.0612 (3)	0.0197 (4)
H11A	0.8939	0.2020	−0.0459	0.029*
H11B	0.7744	0.2490	−0.0487	0.029*
H11C	0.7493	0.1887	−0.2067	0.029*
C12	0.0159 (2)	0.12323 (10)	0.4736 (4)	0.0231 (5)
H12A	−0.0821	0.1294	0.4173	0.028*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cl1	0.0318 (3)	0.0392 (3)	0.0202 (3)	0.0063 (2)	0.0064 (2)	0.0025 (2)
Cl2	0.0281 (3)	0.0258 (3)	0.0401 (4)	−0.0015 (2)	0.0128 (2)	0.0010 (2)
Cl3	0.0394 (3)	0.0294 (3)	0.0264 (3)	−0.0015 (2)	0.0102 (2)	−0.0048 (2)
O1	0.0158 (6)	0.0169 (7)	0.0145 (7)	0.0007 (5)	0.0034 (5)	0.0060 (6)
O2	0.0184 (7)	0.0165 (7)	0.0168 (7)	0.0003 (5)	0.0079 (6)	0.0046 (6)
N1	0.0192 (8)	0.0095 (7)	0.0115 (8)	−0.0006 (6)	0.0053 (6)	0.0004 (6)
C1	0.0184 (9)	0.0062 (8)	0.0120 (9)	0.0000 (7)	0.0023 (7)	−0.0009 (7)
C2	0.0165 (9)	0.0087 (8)	0.0127 (9)	−0.0017 (7)	0.0047 (7)	−0.0021 (7)
C3	0.0230 (10)	0.0084 (9)	0.0124 (10)	−0.0012 (7)	0.0050 (8)	0.0004 (7)
C4	0.0195 (9)	0.0115 (9)	0.0143 (10)	0.0017 (7)	0.0005 (8)	0.0010 (8)
C5	0.0144 (9)	0.0128 (9)	0.0189 (10)	0.0006 (7)	0.0047 (8)	0.0000 (8)
C6	0.0188 (9)	0.0084 (8)	0.0121 (9)	−0.0021 (7)	0.0050 (7)	−0.0023 (7)
C7	0.0170 (9)	0.0116 (9)	0.0167 (10)	−0.0024 (7)	0.0066 (8)	−0.0008 (7)
C8	0.0188 (9)	0.0080 (8)	0.0126 (9)	0.0003 (7)	0.0070 (7)	−0.0024 (7)
C9	0.0151 (9)	0.0138 (9)	0.0186 (10)	−0.0007 (7)	0.0072 (8)	0.0011 (8)
C10	0.0171 (9)	0.0148 (9)	0.0164 (10)	0.0021 (7)	0.0021 (8)	0.0024 (8)
C11	0.0220 (10)	0.0222 (11)	0.0179 (11)	−0.0021 (8)	0.0105 (8)	0.0048 (8)
C12	0.0190 (10)	0.0284 (12)	0.0214 (11)	0.0022 (8)	0.0049 (8)	0.0025 (9)

Geometric parameters (Å, º) top

Cl1—C12	1.768 (2)	C4—H4A	0.9500
Cl2—C12	1.771 (2)	C5—C6	1.408 (3)
Cl3—C12	1.763 (2)	C5—H5A	0.9500
O1—C1	1.354 (2)	C6—C7	1.452 (3)
O1—H1	0.8400	C7—H7A	0.9500
O2—C2	1.369 (2)	C8—C10	1.393 (3)
O2—C11	1.431 (2)	C8—C9	1.400 (3)
N1—C7	1.292 (2)	C9—C10ⁱ	1.381 (3)
N1—C8	1.418 (2)	C9—H9A	0.9500
C1—C6	1.400 (3)	C10—C9ⁱ	1.381 (3)
C1—C2	1.409 (3)	C10—H10A	0.9500
C2—C3	1.383 (3)	C11—H11A	0.9800
C3—C4	1.399 (3)	C11—H11B	0.9800
C3—H3A	0.9500	C11—H11C	0.9800
C4—C5	1.375 (3)	C12—H12A	1.0000

C1—O1—H1	109.5	C6—C7—H7A	119.2
C2—O2—C11	116.63 (14)	C10—C8—C9	118.75 (17)
C7—N1—C8	121.48 (16)	C10—C8—N1	125.04 (17)
O1—C1—C6	122.35 (17)	C9—C8—N1	116.21 (16)
O1—C1—C2	117.87 (16)	C10ⁱ—C9—C8	120.83 (18)
C6—C1—C2	119.78 (16)	C10ⁱ—C9—H9A	119.6
O2—C2—C3	125.84 (17)	C8—C9—H9A	119.6
O2—C2—C1	114.35 (15)	C9ⁱ—C10—C8	120.41 (17)
C3—C2—C1	119.81 (17)	C9ⁱ—C10—H10A	119.8
C2—C3—C4	120.26 (18)	C8—C10—H10A	119.8
C2—C3—H3A	119.9	O2—C11—H11A	109.5
C4—C3—H3A	119.9	O2—C11—H11B	109.5
C5—C4—C3	120.46 (17)	H11A—C11—H11B	109.5
C5—C4—H4A	119.8	O2—C11—H11C	109.5
C3—C4—H4A	119.8	H11A—C11—H11C	109.5
C4—C5—C6	120.21 (18)	H11B—C11—H11C	109.5
C4—C5—H5A	119.9	Cl3—C12—Cl1	110.39 (12)
C6—C5—H5A	119.9	Cl3—C12—Cl2	110.22 (12)
C1—C6—C5	119.47 (17)	Cl1—C12—Cl2	109.93 (12)
C1—C6—C7	120.62 (17)	Cl3—C12—H12A	108.7
C5—C6—C7	119.90 (17)	Cl1—C12—H12A	108.7
N1—C7—C6	121.54 (17)	Cl2—C12—H12A	108.7
N1—C7—H7A	119.2

C11—O2—C2—C3	3.6 (3)	C2—C1—C6—C7	179.44 (17)
C11—O2—C2—C1	−176.48 (16)	C4—C5—C6—C1	−0.3 (3)
O1—C1—C2—O2	1.5 (2)	C4—C5—C6—C7	−179.84 (17)
C6—C1—C2—O2	−179.08 (16)	C8—N1—C7—C6	−178.93 (16)
O1—C1—C2—C3	−178.60 (16)	C1—C6—C7—N1	−2.4 (3)
C6—C1—C2—C3	0.9 (3)	C5—C6—C7—N1	177.12 (17)
O2—C2—C3—C4	178.67 (17)	C7—N1—C8—C10	11.6 (3)
C1—C2—C3—C4	−1.3 (3)	C7—N1—C8—C9	−169.16 (17)
C2—C3—C4—C5	0.9 (3)	C10—C8—C9—C10ⁱ	−0.9 (3)
C3—C4—C5—C6	−0.1 (3)	N1—C8—C9—C10ⁱ	179.83 (17)
O1—C1—C6—C5	179.37 (17)	C9—C8—C10—C9ⁱ	0.9 (3)
C2—C1—C6—C5	−0.1 (3)	N1—C8—C10—C9ⁱ	−179.90 (17)
O1—C1—C6—C7	−1.1 (3)

Symmetry code: (i) −x+1, −y, −z+2.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···N1	0.84	1.84	2.584 (2)	147
C12—H12A···O1ⁱⁱ	1.00	2.21	3.120 (3)	150
C12—H12A···O2ⁱⁱ	1.00	2.30	3.121 (3)	139
C3—H3A···Cg1ⁱⁱⁱ	0.95	2.73	3.5221 (19)	142

Symmetry codes: (ii) x−1, y, z; (iii) x, −y−1/2, z−3/2.

Experimental details

Crystal data
Chemical formula	C₂₂H₂₀N₂O₄·2CHCl₃
M_r	615.14
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	100
a, b, c (Å)	10.4773 (2), 21.3287 (5), 6.2424 (2)
β (°)	105.669 (2)
V (Å³)	1343.13 (6)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.67
Crystal size (mm)	0.54 × 0.18 × 0.07

Data collection
Diffractometer	Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2005)
T_min, T_max	0.712, 0.958
No. of measured, independent and observed [I > 2σ(I)] reflections	10624, 3069, 2361
R_int	0.033
(sin θ/λ)_max (Å⁻¹)	0.650

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.036, 0.090, 1.03
No. of reflections	3069
No. of parameters	165
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.35, −0.25

Computer programs: APEX2 (Bruker, 2005), SAINT (Bruker, 2005), SHELXTL (Sheldrick, 2008), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···N1	0.8400	1.8400	2.584 (2)	147.00
C12—H12A···O1ⁱ	1.0000	2.2100	3.120 (3)	150.00
C12—H12A···O2ⁱ	1.0000	2.3000	3.121 (3)	139.00
C3—H3A···Cg1ⁱⁱ	0.9500	2.7300	3.5221 (19)	142.00

Symmetry codes: (i) x−1, y, z; (ii) x, −y−1/2, z−3/2.

Footnotes

‡Additional correspondence author, e-mail: ohasnah@usm.my.

Acknowledgements

We thank the Malaysian Government and Universiti Sains Malaysia for an FRGS grant [304/PKIMIA/638122] to conduct this work. MHAl-D thanks the Yemen Government and Hadhramout University of Science and Technology for financial scholarship support. 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 a post-doctoral research fellowship. HKF also thanks Universiti Sains Malaysia for the Research University Golden Goose grant No. 1001/PFIZIK/811012.

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