{5-Chloro-2-[(4-chloro­benzyl­idene)­amino]­phen­yl}(phen­yl)methanone

Aslam, M.; Anis, I.; Afza, N.; Yasmeen, S.; Yousuf, S.

doi:10.1107/S1600536812004655

organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 68| Part 3| March 2012| Page o644

doi:10.1107/S1600536812004655

Open

access

{5-Chloro-2-[(4-chlorobenzylidene)amino]phenyl}(phenyl)methanone

Muhammad Aslam,^a,^b ‡ Itrat Anis,^b Nighat Afza,^a Shazia Yasmeen ^a and Sammer Yousuf ^c ^*

^aPharmaceutical Research Centre, PCSIR Laboratories Complex, Karachi, Pakistan, ^bDepartment of Chemistry, University of Karachi, Karachi, Pakistan, and ^cHEJ Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan
^*Correspondence e-mail: dr.sammer.yousuf@gmail.com

(Received 8 January 2012; accepted 3 February 2012; online 10 February 2012)

In the title compound, C₂₀H₁₃Cl₂NO, the C=N bond adopts an E conformation. The chloro-substituted rings form a dihedral angle of 11.99 (9)° with each other and form dihedral angles of 74.95 (9) and 83.26 (10)° with the unsubstituted ring. In the crystal, molecules are connected into dimers by pairs of weak C—H⋯O hydrogen bonds and the dimers are arranged in columns parallel to the a axis.

Related literature

For the biological activities of Schiff base compounds, see: Solomon & Lowery (1993 ). For related structures, see: Aslam et al. (2011a ,b ); Zeb & Yousuf (2011 ).

Experimental

Crystal data

C₂₀H₁₃Cl₂NO
M_r = 354.21
Triclinic, $[P \overline 1]$
a = 7.2283 (4) Å
b = 10.2301 (5) Å
c = 11.9079 (6) Å
α = 100.929 (1)°
β = 97.318 (1)°
γ = 91.360 (1)°
V = 856.49 (8) Å³
Z = 2
Mo Kα radiation
μ = 0.38 mm⁻¹
T = 273 K
0.39 × 0.14 × 0.10 mm

Data collection

Bruker SMART APEX CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2000 ) T_min = 0.865, T_max = 0.963
9733 measured reflections
3186 independent reflections
2388 reflections with I > 2σ(I)
R_int = 0.025

Refinement

R[F² > 2σ(F²)] = 0.037
wR(F²) = 0.102
S = 1.02
3186 reflections
217 parameters
H-atom parameters constrained
Δρ_max = 0.18 e Å⁻³
Δρ_min = −0.23 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C9—H9A⋯O1ⁱ	0.93	2.52	3.426 (2)	164
Symmetry code: (i) -x, -y, -z+2.

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL, PARST (Nardelli, 1995 ) and PLATON (Spek, 2009 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536812004655/lh5403sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536812004655/lh5403Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536812004655/lh5403Isup3.cml

checkCIF report

Comment top

Schiff bases are well known ligands in synthetic chemistry and have a wide range of bilogical activities (Solomon & Lowery, 1993). The title compound (I) (Fig. 1) is a schiff base structurally similar to our recently published compound {5-chloro-2-[(4-nitrobenzylidene)amino]phenyl}(phenyl)methanone (Aslam et al., 2011b) with a difference that the nitro group on the benzene ring (C15-C20) is replaced by a chloro group in the title compound. The torsion angle of the E configurated double bond (C═N, 1.253 (2) Å) is 177.31 (15)° for C13-N1-C14-C15. The bond lengths and angles are similar to those in the previously reported structural analogue (Aslam et al., 2011b). We have published other crystal structures of this type of compound (Aslam et al., 2011a; Zeb & Yousuf, 2011). In the crystal, molecules are linked into dimers via weak C9—H9A···O1ⁱ intermolecular hydrogen bonds (symmetry code as in Table 1) and arranged in columns parallel to the a axis.

Related literature top

For the biological activities of Schiff base compounds, see: Solomon & Lowery (1993). For related structures, see: Aslam et al. (2011a,b); Zeb & Yousuf (2011).

Experimental top

The synthesis of title compound was carried out by refluxing a mixture of 4-chlorobenzaldehyde (1 mol) and 2-amino-5-chlorobenzophenone (1 mol) in ethanol (50 ml) along with 3 drops of conc. H₂SO₄ for 5 h at 343 K. After cooling, the mixture was concentrated to one third under reduced pressure. The concentrated reaction mixture was kept at room temperature and yellow crystals were obtained after nine days. The crystalline product was collected, washed with methanol and dried to afford the title compound in 85% yield. Slow evaporation of a methanol solution afforded yellow crystals which were suitable for single-crystal X-ray diffraction studies. All chemicals were purchased from Sigma-Aldrich.

Computing details top

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT (Bruker, 2000); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008), PARST (Nardelli, 1995) and PLATON (Spek, 2009).

Figures top

	Fig. 1. The molecular structure of (I) with displacement ellipsoids drawn at 30% probability level.
	Fig. 2. The crystal packing of (I) with hydrogen bonds shown as dashed lines. Only hydrogen atoms involved in hydrogen bonding are shown.

{5-Chloro-2-[(4-chlorobenzylidene)amino]phenyl}(phenyl)methanone top

Crystal data top

C₂₀H₁₃Cl₂NO	Z = 2
M_r = 354.21	F(000) = 364
Triclinic, P1	D_x = 1.373 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.2283 (4) Å	Cell parameters from 2693 reflections
b = 10.2301 (5) Å	θ = 2.4–25.0°
c = 11.9079 (6) Å	µ = 0.38 mm⁻¹
α = 100.929 (1)°	T = 273 K
β = 97.318 (1)°	Block, yellow
γ = 91.360 (1)°	0.39 × 0.14 × 0.10 mm
V = 856.49 (8) Å³

Data collection top

Bruker SMART APEX CCD diffractometer	3186 independent reflections
Radiation source: fine-focus sealed tube	2388 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.025
ω scans	θ_max = 25.5°, θ_min = 1.8°
Absorption correction: multi-scan (SADABS; Bruker, 2000)	h = −8→8
T_min = 0.865, T_max = 0.963	k = −12→12
9733 measured reflections	l = −14→14

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)] = 0.037	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.102	H-atom parameters constrained
S = 1.02	w = 1/[σ²(F_o²) + (0.0503P)² + 0.1325P] where P = (F_o² + 2F_c²)/3
3186 reflections	(Δ/σ)_max = 0.001
217 parameters	Δρ_max = 0.18 e Å⁻³
0 restraints	Δρ_min = −0.23 e Å⁻³

Crystal data top

C₂₀H₁₃Cl₂NO	γ = 91.360 (1)°
M_r = 354.21	V = 856.49 (8) Å³
Triclinic, P1	Z = 2
a = 7.2283 (4) Å	Mo Kα radiation
b = 10.2301 (5) Å	µ = 0.38 mm⁻¹
c = 11.9079 (6) Å	T = 273 K
α = 100.929 (1)°	0.39 × 0.14 × 0.10 mm
β = 97.318 (1)°

Data collection top

Bruker SMART APEX CCD diffractometer	3186 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2000)	2388 reflections with I > 2σ(I)
T_min = 0.865, T_max = 0.963	R_int = 0.025
9733 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.037	0 restraints
wR(F²) = 0.102	H-atom parameters constrained
S = 1.02	Δρ_max = 0.18 e Å⁻³
3186 reflections	Δρ_min = −0.23 e Å⁻³
217 parameters

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.

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

	x	y	z	U_iso*/U_eq
Cl1	0.21952 (9)	0.72197 (6)	0.48534 (5)	0.0772 (2)
Cl2	0.26120 (8)	0.21797 (7)	1.37525 (4)	0.0772 (2)
O1	−0.06787 (19)	0.12992 (15)	0.92259 (12)	0.0703 (4)
N1	0.2217 (2)	0.43376 (15)	0.94686 (13)	0.0534 (4)
C1	0.3968 (3)	0.1501 (2)	0.85494 (17)	0.0593 (5)
H1B	0.4588	0.1680	0.9300	0.071*
C2	0.4979 (3)	0.1263 (2)	0.7624 (2)	0.0747 (7)
H2A	0.6275	0.1257	0.7753	0.090*
C3	0.4060 (4)	0.1037 (2)	0.65140 (19)	0.0715 (6)
H3A	0.4740	0.0911	0.5893	0.086*
C4	0.2164 (3)	0.0997 (2)	0.63220 (17)	0.0640 (6)
H4A	0.1549	0.0833	0.5570	0.077*
C5	0.1152 (3)	0.12004 (19)	0.72373 (16)	0.0542 (5)
H5A	−0.0146	0.1154	0.7100	0.065*
C6	0.2049 (2)	0.14729 (16)	0.83616 (14)	0.0448 (4)
C7	0.0923 (3)	0.17452 (17)	0.93309 (15)	0.0465 (4)
C8	0.1764 (2)	0.25790 (17)	1.04654 (14)	0.0443 (4)
C9	0.1823 (2)	0.20517 (19)	1.14596 (15)	0.0507 (4)
H9A	0.1410	0.1174	1.1419	0.061*
C10	0.2499 (3)	0.2842 (2)	1.25056 (15)	0.0520 (5)
C11	0.3079 (3)	0.4151 (2)	1.25924 (16)	0.0566 (5)
H11A	0.3517	0.4674	1.3309	0.068*
C12	0.3006 (3)	0.4679 (2)	1.16108 (16)	0.0560 (5)
H12A	0.3397	0.5564	1.1668	0.067*
C13	0.2355 (2)	0.39071 (17)	1.05307 (14)	0.0453 (4)
C14	0.2384 (2)	0.55370 (18)	0.93892 (15)	0.0483 (4)
H14A	0.2559	0.6186	1.0061	0.058*
C15	0.2314 (2)	0.59480 (17)	0.82787 (15)	0.0448 (4)
C16	0.2588 (3)	0.72787 (18)	0.82228 (16)	0.0522 (5)
H16A	0.2787	0.7915	0.8902	0.063*
C17	0.2569 (3)	0.76737 (19)	0.71788 (17)	0.0550 (5)
H17A	0.2763	0.8568	0.7151	0.066*
C18	0.2260 (3)	0.6728 (2)	0.61789 (16)	0.0519 (5)
C19	0.1977 (3)	0.5396 (2)	0.62006 (17)	0.0595 (5)
H19A	0.1768	0.4766	0.5518	0.071*
C20	0.2007 (3)	0.50153 (19)	0.72493 (16)	0.0559 (5)
H20A	0.1819	0.4119	0.7272	0.067*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cl1	0.1037 (5)	0.0795 (4)	0.0541 (3)	−0.0031 (3)	0.0087 (3)	0.0294 (3)
Cl2	0.0884 (4)	0.1037 (5)	0.0477 (3)	0.0080 (3)	0.0099 (3)	0.0346 (3)
O1	0.0583 (9)	0.0847 (10)	0.0620 (9)	−0.0190 (8)	0.0089 (7)	0.0014 (7)
N1	0.0718 (11)	0.0451 (9)	0.0437 (9)	−0.0017 (7)	0.0051 (7)	0.0119 (7)
C1	0.0574 (12)	0.0635 (13)	0.0513 (11)	−0.0004 (10)	0.0015 (9)	0.0013 (9)
C2	0.0594 (13)	0.0807 (16)	0.0788 (16)	−0.0021 (11)	0.0199 (12)	−0.0038 (12)
C3	0.0960 (18)	0.0620 (13)	0.0584 (13)	−0.0072 (12)	0.0325 (12)	0.0032 (10)
C4	0.0888 (16)	0.0603 (13)	0.0429 (11)	−0.0038 (11)	0.0063 (10)	0.0130 (9)
C5	0.0624 (12)	0.0537 (11)	0.0463 (10)	0.0001 (9)	0.0008 (9)	0.0136 (8)
C6	0.0529 (10)	0.0389 (9)	0.0415 (9)	−0.0020 (8)	0.0026 (8)	0.0081 (7)
C7	0.0496 (10)	0.0441 (10)	0.0461 (10)	−0.0027 (8)	0.0024 (8)	0.0125 (8)
C8	0.0453 (9)	0.0475 (10)	0.0407 (9)	0.0010 (8)	0.0077 (7)	0.0091 (8)
C9	0.0518 (10)	0.0567 (11)	0.0474 (10)	−0.0009 (9)	0.0094 (8)	0.0181 (9)
C10	0.0489 (10)	0.0710 (13)	0.0404 (10)	0.0094 (9)	0.0077 (8)	0.0196 (9)
C11	0.0618 (12)	0.0670 (13)	0.0385 (10)	0.0059 (10)	0.0053 (8)	0.0044 (9)
C12	0.0702 (13)	0.0476 (11)	0.0475 (11)	−0.0010 (9)	0.0056 (9)	0.0044 (9)
C13	0.0490 (10)	0.0479 (10)	0.0398 (9)	0.0030 (8)	0.0074 (8)	0.0092 (8)
C14	0.0542 (11)	0.0454 (11)	0.0445 (10)	0.0002 (8)	0.0061 (8)	0.0072 (8)
C15	0.0428 (9)	0.0440 (10)	0.0482 (10)	0.0010 (7)	0.0063 (8)	0.0107 (8)
C16	0.0638 (12)	0.0421 (10)	0.0499 (11)	0.0017 (8)	0.0069 (9)	0.0076 (8)
C17	0.0655 (12)	0.0439 (10)	0.0581 (12)	0.0002 (9)	0.0082 (9)	0.0163 (9)
C18	0.0523 (10)	0.0586 (12)	0.0480 (11)	0.0010 (9)	0.0063 (8)	0.0190 (9)
C19	0.0775 (13)	0.0526 (12)	0.0459 (11)	−0.0047 (10)	0.0041 (9)	0.0069 (9)
C20	0.0710 (13)	0.0426 (10)	0.0539 (11)	−0.0041 (9)	0.0052 (9)	0.0119 (9)

Geometric parameters (Å, º) top

Cl1—C18	1.7406 (18)	C9—C10	1.374 (3)
Cl2—C10	1.7389 (18)	C9—H9A	0.9300
O1—C7	1.217 (2)	C10—C11	1.375 (3)
N1—C14	1.253 (2)	C11—C12	1.373 (3)
N1—C13	1.409 (2)	C11—H11A	0.9300
C1—C6	1.375 (3)	C12—C13	1.394 (2)
C1—C2	1.385 (3)	C12—H12A	0.9300
C1—H1B	0.9300	C14—C15	1.457 (2)
C2—C3	1.377 (3)	C14—H14A	0.9300
C2—H2A	0.9300	C15—C16	1.386 (2)
C3—C4	1.359 (3)	C15—C20	1.393 (3)
C3—H3A	0.9300	C16—C17	1.377 (3)
C4—C5	1.375 (3)	C16—H16A	0.9300
C4—H4A	0.9300	C17—C18	1.374 (3)
C5—C6	1.385 (2)	C17—H17A	0.9300
C5—H5A	0.9300	C18—C19	1.379 (3)
C6—C7	1.483 (2)	C19—C20	1.375 (3)
C7—C8	1.501 (2)	C19—H19A	0.9300
C8—C9	1.387 (2)	C20—H20A	0.9300
C8—C13	1.399 (2)

C14—N1—C13	123.34 (16)	C12—C11—C10	119.37 (17)
C6—C1—C2	120.21 (19)	C12—C11—H11A	120.3
C6—C1—H1B	119.9	C10—C11—H11A	120.3
C2—C1—H1B	119.9	C11—C12—C13	120.96 (18)
C3—C2—C1	119.8 (2)	C11—C12—H12A	119.5
C3—C2—H2A	120.1	C13—C12—H12A	119.5
C1—C2—H2A	120.1	C12—C13—C8	118.58 (16)
C4—C3—C2	120.3 (2)	C12—C13—N1	126.03 (17)
C4—C3—H3A	119.9	C8—C13—N1	115.39 (15)
C2—C3—H3A	119.9	N1—C14—C15	122.11 (17)
C3—C4—C5	120.1 (2)	N1—C14—H14A	118.9
C3—C4—H4A	119.9	C15—C14—H14A	118.9
C5—C4—H4A	119.9	C16—C15—C20	118.33 (17)
C4—C5—C6	120.57 (19)	C16—C15—C14	120.65 (16)
C4—C5—H5A	119.7	C20—C15—C14	121.01 (16)
C6—C5—H5A	119.7	C17—C16—C15	121.11 (17)
C1—C6—C5	118.97 (17)	C17—C16—H16A	119.4
C1—C6—C7	121.64 (16)	C15—C16—H16A	119.4
C5—C6—C7	119.38 (16)	C18—C17—C16	119.08 (17)
O1—C7—C6	121.13 (16)	C18—C17—H17A	120.5
O1—C7—C8	119.03 (16)	C16—C17—H17A	120.5
C6—C7—C8	119.84 (15)	C17—C18—C19	121.44 (17)
C9—C8—C13	120.33 (16)	C17—C18—Cl1	119.46 (15)
C9—C8—C7	119.33 (16)	C19—C18—Cl1	119.10 (15)
C13—C8—C7	120.17 (15)	C20—C19—C18	118.84 (18)
C10—C9—C8	119.20 (17)	C20—C19—H19A	120.6
C10—C9—H9A	120.4	C18—C19—H19A	120.6
C8—C9—H9A	120.4	C19—C20—C15	121.20 (17)
C9—C10—C11	121.53 (17)	C19—C20—H20A	119.4
C9—C10—Cl2	119.45 (16)	C15—C20—H20A	119.4
C11—C10—Cl2	119.01 (15)

C6—C1—C2—C3	1.9 (3)	C10—C11—C12—C13	0.0 (3)
C1—C2—C3—C4	−2.4 (4)	C11—C12—C13—C8	0.3 (3)
C2—C3—C4—C5	0.8 (3)	C11—C12—C13—N1	180.00 (17)
C3—C4—C5—C6	1.3 (3)	C9—C8—C13—C12	0.3 (3)
C2—C1—C6—C5	0.2 (3)	C7—C8—C13—C12	175.50 (16)
C2—C1—C6—C7	−178.95 (19)	C9—C8—C13—N1	−179.44 (15)
C4—C5—C6—C1	−1.8 (3)	C7—C8—C13—N1	−4.2 (2)
C4—C5—C6—C7	177.37 (17)	C14—N1—C13—C12	−12.0 (3)
C1—C6—C7—O1	−154.66 (19)	C14—N1—C13—C8	167.63 (18)
C5—C6—C7—O1	26.2 (3)	C13—N1—C14—C15	177.31 (15)
C1—C6—C7—C8	25.1 (3)	N1—C14—C15—C16	−177.10 (18)
C5—C6—C7—C8	−154.06 (16)	N1—C14—C15—C20	1.7 (3)
O1—C7—C8—C9	57.0 (2)	C20—C15—C16—C17	−0.4 (3)
C6—C7—C8—C9	−122.72 (18)	C14—C15—C16—C17	178.42 (16)
O1—C7—C8—C13	−118.3 (2)	C15—C16—C17—C18	0.5 (3)
C6—C7—C8—C13	62.0 (2)	C16—C17—C18—C19	−0.3 (3)
C13—C8—C9—C10	−1.1 (3)	C16—C17—C18—Cl1	178.94 (14)
C7—C8—C9—C10	−176.41 (16)	C17—C18—C19—C20	0.0 (3)
C8—C9—C10—C11	1.4 (3)	Cl1—C18—C19—C20	−179.23 (15)
C8—C9—C10—Cl2	−178.96 (13)	C18—C19—C20—C15	0.1 (3)
C9—C10—C11—C12	−0.9 (3)	C16—C15—C20—C19	0.1 (3)
Cl2—C10—C11—C12	179.54 (14)	C14—C15—C20—C19	−178.70 (17)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C9—H9A···O1ⁱ	0.93	2.52	3.426 (2)	164

Symmetry code: (i) −x, −y, −z+2.

Experimental details

Crystal data
Chemical formula	C₂₀H₁₃Cl₂NO
M_r	354.21
Crystal system, space group	Triclinic, P1
Temperature (K)	273
a, b, c (Å)	7.2283 (4), 10.2301 (5), 11.9079 (6)
α, β, γ (°)	100.929 (1), 97.318 (1), 91.360 (1)
V (Å³)	856.49 (8)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.38
Crystal size (mm)	0.39 × 0.14 × 0.10

Data collection
Diffractometer	Bruker SMART APEX CCD diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2000)
T_min, T_max	0.865, 0.963
No. of measured, independent and observed [I > 2σ(I)] reflections	9733, 3186, 2388
R_int	0.025
(sin θ/λ)_max (Å⁻¹)	0.606

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.037, 0.102, 1.02
No. of reflections	3186
No. of parameters	217
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.18, −0.23

Computer programs: SMART (Bruker, 2000), SAINT (Bruker, 2000), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008), PARST (Nardelli, 1995) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C9—H9A···O1ⁱ	0.9300	2.5200	3.426 (2)	164.00

Symmetry code: (i) −x, −y, −z+2.

Footnotes

‡Additional correspondence author, e-mail: maslamchemist@hotmail.com.

Acknowledgements

MA expresses his gratitude to the Pakistan Council of Scientific and Industrial Research Laboratories Complex, Karachi, the Department of Chemistry, University of Karachi, and the HEJ Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, for providing financial support, research facilities and X-ray diffraction facilities, respectively.

References

Aslam, M., Anis, I., Afza, N., Nelofar, A. & Yousuf, S. (2011a). Acta Cryst. E67, o3442–o3443. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Aslam, M., Anis, I., Afza, N., Nelofar, A. & Yousuf, S. (2011b). Acta Cryst. E67, o3215. Web of Science CSD CrossRef IUCr Journals Google Scholar
Bruker (2000). SMART, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Nardelli, M. (1995). J. Appl. Cryst. 28, 659. CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Solomon, E. I. & Lowery, M. D. (1993). Science, 259, 1575–1581. CrossRef CAS PubMed Web of Science Google Scholar
Spek, A. L. (2009). Acta Cryst. D65, 148–155. Web of Science CrossRef CAS IUCr Journals Google Scholar
Zeb, A. & Yousuf, S. (2011). Acta Cryst. E67, o2801. Web of Science CSD CrossRef IUCr Journals Google Scholar