Bis{2-bromo-4-chloro-6-[2-(phenyl­sulfon­yl)hydrazonometh­yl]phenolato-κ2N,O1}copper(II)

Yusnita, J.; Ali, H.M.; Puvaneswary, S.; Robinson, W.T.; Ng, S.W.

doi:10.1107/S1600536808022022

metal-organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 64| Part 8| August 2008| Page m1039

doi:10.1107/S1600536808022022

Open

access

Bis{2-bromo-4-chloro-6-[2-(phenylsulfonyl)hydrazonomethyl]phenolato-κ²N,O¹}copper(II)

Juahir Yusnita,^a Hapipah M. Ali,^a Subramaniam Puvaneswary,^a Ward T. Robinson ^a and Seik Weng Ng ^a ^*

^aDepartment of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
^*Correspondence e-mail: seikweng@um.edu.my

(Received 10 July 2008; accepted 15 July 2008; online 19 July 2008)

The Cu atom in the title compound, [Cu(C₁₃H₉BrClN₂O₃S)₂], is chelated by two deprotonated Schiff base ligands in a square-planar coordination geometry; the Cu atom lies on a center of inversion. The –NH– group of one anion forms an intramolecular hydrogen bond to the phenolate atom of the symmetry-related ion.

Related literature

For the structure of the copper derivative of a similar Schiff base ligand, see: Ali et al. (2007 ).

Experimental

Crystal data

[Cu(C₁₃H₉BrClN₂O₃S)₂]
M_r = 840.82
Triclinic, $[P \overline 1]$
a = 8.0688 (1) Å
b = 8.2755 (1) Å
c = 11.7386 (2) Å
α = 95.955 (1)°
β = 90.133 (1)°
γ = 115.159 (1)°
V = 704.70 (2) Å³
Z = 1
Mo Kα radiation
μ = 4.00 mm⁻¹
T = 100 (2) K
0.20 × 0.09 × 0.09 mm

Data collection

Bruker SMART APEX diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ) T_min = 0.502, T_max = 0.715
8995 measured reflections
3214 independent reflections
2928 reflections with I > 2σ(I)
R_int = 0.017

Refinement

R[F² > 2σ(F²)] = 0.021
wR(F²) = 0.061
S = 1.05
3214 reflections
200 parameters
1 restraint
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.52 e Å⁻³
Δρ_min = −0.29 e Å⁻³

Table 1
Selected geometric parameters (Å, °)

Cu1—O1	1.905 (1)
Cu1—N1	1.963 (2)

O1—Cu1—N1	91.28 (6)
O1—Cu1—N1ⁱ	88.72 (6)
Symmetry code: (i) -x+1, -y+1, -z+1.

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H2N⋯O1ⁱ	0.88 (1)	2.07 (2)	2.722 (2)	130 (2)
Symmetry code: (i) -x+1, -y+1, -z+1.

Data collection: APEX2 (Bruker, 2007 ); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001 ); software used to prepare material for publication: publCIF (Westrip, 2008 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808022022/hg2424sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808022022/hg2424Isup2.hkl

checkCIF report

Comment top

The present study continues with a study on the copper derivative of Schiff-base condensation products from the reaction between substituted salicylaldehydes and benzene sulfonylhydrazine. The two monoanions chelate to the copper atom, which shows square-planar coordination (Ali et al., 2007). The present copper derivative (Scheme I, Fig. 1), which has a bromine substituent in the aromatic system, shows such a geometry; the nature of the substituent in the salicylaldehyde portion does not have an effect on the overall geometry.

Related literature top

For the structure of the copper derivative of a similar Schiff base ligand, see: Ali et al. (2007).

Experimental top

3-Bromo-5-chlorobenzaldehyde (0.5 g, 0.3 mmol) and benzenesulfonylhydrazine (0.5 g, 0.3 mmol) were condensed in refluxing ethanol (100 ml) for two hours. The solvent was removed to give the Schiff base, which was collected and dried. The ligand (0.6 g, 2 mmol) and copper acetate (0.2 g, 1 mmol) were heated in ethanol (100 ml) for two hours. The solvent was removed and the product recrystallized from DMSO.

Computing details top

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001); software used to prepare material for publication: publCIF (Westrip, 2008).

Figures top

Fig. 1. Thermal ellipsoid plot (Barbour, 2001) plot of Cu(C₁₃H₉BrClN₂O₃S)₂ at the 70% probability level. Hydrogen atoms are drawn as spheres of arbitrary radius. Hydrogen bonds are denoted by dashed lines. The copper atom lies on a center of inversion, and unlabeled atoms are related to their labeled equivalents by 1 – x, 1 – y, 1 – z.

Bis{2-bromo-4-chloro-6-[2-(phenylsulfonyl)hydrazonomethyl]phenolato- κ²N,O¹}copper(II) top

Crystal data top

[Cu(C₁₃H₉BrClN₂O₃S)₂]	Z = 1
M_r = 840.82	F(000) = 415
Triclinic, P1	D_x = 1.981 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 8.0688 (1) Å	Cell parameters from 5423 reflections
b = 8.2755 (1) Å	θ = 2.7–28.4°
c = 11.7386 (2) Å	µ = 4.00 mm⁻¹
α = 95.955 (1)°	T = 100 K
β = 90.133 (1)°	Block, purple
γ = 115.159 (1)°	0.20 × 0.09 × 0.09 mm
V = 704.70 (2) Å³

Data collection top

Bruker SMART APEX diffractometer	3214 independent reflections
Radiation source: fine-focus sealed tube	2928 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.017
ω scans	θ_max = 27.5°, θ_min = 1.8°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −8→10
T_min = 0.502, T_max = 0.715	k = −10→10
8995 measured reflections	l = −15→15

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)] = 0.021	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.061	H atoms treated by a mixture of independent and constrained refinement
S = 1.05	w = 1/[σ²(F_o²) + (0.0332P)² + 0.5714P] where P = (F_o² + 2F_c²)/3
3214 reflections	(Δ/σ)_max = 0.001
200 parameters	Δρ_max = 0.52 e Å⁻³
1 restraint	Δρ_min = −0.29 e Å⁻³

Crystal data top

[Cu(C₁₃H₉BrClN₂O₃S)₂]	γ = 115.159 (1)°
M_r = 840.82	V = 704.70 (2) Å³
Triclinic, P1	Z = 1
a = 8.0688 (1) Å	Mo Kα radiation
b = 8.2755 (1) Å	µ = 4.00 mm⁻¹
c = 11.7386 (2) Å	T = 100 K
α = 95.955 (1)°	0.20 × 0.09 × 0.09 mm
β = 90.133 (1)°

Data collection top

Bruker SMART APEX diffractometer	3214 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	2928 reflections with I > 2σ(I)
T_min = 0.502, T_max = 0.715	R_int = 0.017
8995 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.021	1 restraint
wR(F²) = 0.061	H atoms treated by a mixture of independent and constrained refinement
S = 1.05	Δρ_max = 0.52 e Å⁻³
3214 reflections	Δρ_min = −0.29 e Å⁻³
200 parameters

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

	x	y	z	U_iso*/U_eq
Br1	0.46994 (3)	0.68016 (3)	0.125566 (17)	0.01926 (7)
Cu1	0.5000	0.5000	0.5000	0.01271 (9)
Cl1	−0.18066 (7)	0.07143 (7)	0.02818 (4)	0.02134 (12)
S1	0.09184 (7)	0.33794 (7)	0.69365 (4)	0.01590 (11)
O1	0.4287 (2)	0.53987 (19)	0.35457 (12)	0.0156 (3)
O2	−0.0713 (2)	0.2946 (2)	0.62483 (13)	0.0201 (3)
O3	0.0825 (2)	0.2833 (2)	0.80598 (13)	0.0223 (3)
N1	0.2591 (2)	0.2994 (2)	0.51073 (14)	0.0139 (3)
N2	0.2075 (2)	0.2348 (2)	0.62019 (14)	0.0149 (3)
H2N	0.309 (2)	0.267 (4)	0.663 (2)	0.025 (7)*
C1	0.2899 (3)	0.4324 (3)	0.28525 (17)	0.0142 (4)
C2	0.2784 (3)	0.4722 (3)	0.17138 (17)	0.0150 (4)
C3	0.1374 (3)	0.3636 (3)	0.09341 (17)	0.0165 (4)
H3	0.1350	0.3938	0.0177	0.020*
C4	−0.0018 (3)	0.2085 (3)	0.12702 (17)	0.0161 (4)
C5	0.0002 (3)	0.1631 (3)	0.23553 (17)	0.0162 (4)
H5	−0.0958	0.0571	0.2570	0.019*
C6	0.1451 (3)	0.2739 (3)	0.31582 (16)	0.0140 (4)
C7	0.1325 (3)	0.2211 (3)	0.42942 (17)	0.0151 (4)
H7	0.0238	0.1219	0.4461	0.018*
C8	0.2345 (3)	0.5685 (3)	0.69679 (18)	0.0168 (4)
C9	0.2357 (3)	0.6526 (3)	0.60000 (18)	0.0175 (4)
H9	0.1500	0.5902	0.5372	0.021*
C10	0.3634 (3)	0.8287 (3)	0.5961 (2)	0.0215 (4)
H10	0.3658	0.8877	0.5305	0.026*
C11	0.4881 (3)	0.9189 (3)	0.6887 (2)	0.0254 (5)
H11	0.5770	1.0388	0.6856	0.030*
C12	0.4833 (3)	0.8350 (3)	0.7848 (2)	0.0269 (5)
H12	0.5673	0.8987	0.8481	0.032*
C13	0.3572 (3)	0.6584 (3)	0.79044 (19)	0.0216 (4)
H13	0.3547	0.6004	0.8566	0.026*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Br1	0.02148 (12)	0.01787 (11)	0.01395 (11)	0.00366 (9)	−0.00187 (8)	0.00401 (7)
Cu1	0.01245 (17)	0.01403 (16)	0.00878 (16)	0.00304 (13)	−0.00122 (12)	0.00080 (12)
Cl1	0.0154 (2)	0.0276 (3)	0.0122 (2)	0.0018 (2)	−0.00463 (18)	−0.00208 (19)
S1	0.0156 (2)	0.0193 (2)	0.0112 (2)	0.0056 (2)	0.00112 (18)	0.00311 (18)
O1	0.0151 (7)	0.0171 (7)	0.0111 (7)	0.0035 (6)	−0.0023 (5)	0.0018 (5)
O2	0.0148 (7)	0.0249 (8)	0.0179 (7)	0.0054 (6)	0.0001 (6)	0.0047 (6)
O3	0.0253 (8)	0.0291 (8)	0.0123 (7)	0.0107 (7)	0.0031 (6)	0.0054 (6)
N1	0.0167 (9)	0.0141 (8)	0.0095 (8)	0.0052 (7)	0.0006 (6)	0.0018 (6)
N2	0.0160 (9)	0.0166 (8)	0.0106 (8)	0.0051 (7)	−0.0009 (6)	0.0029 (6)
C1	0.0146 (10)	0.0162 (9)	0.0121 (9)	0.0074 (8)	−0.0016 (7)	−0.0007 (7)
C2	0.0161 (10)	0.0148 (9)	0.0134 (9)	0.0061 (8)	0.0005 (8)	0.0012 (7)
C3	0.0181 (10)	0.0214 (10)	0.0111 (9)	0.0096 (9)	−0.0002 (8)	0.0014 (8)
C4	0.0132 (10)	0.0196 (10)	0.0129 (9)	0.0060 (8)	−0.0037 (7)	−0.0043 (7)
C5	0.0145 (10)	0.0171 (9)	0.0149 (9)	0.0055 (8)	0.0002 (8)	−0.0014 (7)
C6	0.0147 (10)	0.0158 (9)	0.0112 (9)	0.0064 (8)	−0.0006 (7)	0.0003 (7)
C7	0.0155 (10)	0.0140 (9)	0.0139 (9)	0.0048 (8)	0.0003 (8)	0.0005 (7)
C8	0.0162 (10)	0.0177 (9)	0.0158 (9)	0.0074 (8)	0.0002 (8)	−0.0015 (8)
C9	0.0160 (10)	0.0184 (10)	0.0165 (10)	0.0062 (8)	−0.0006 (8)	0.0001 (8)
C10	0.0200 (11)	0.0198 (10)	0.0242 (11)	0.0079 (9)	0.0035 (9)	0.0027 (9)
C11	0.0190 (11)	0.0190 (11)	0.0330 (13)	0.0053 (9)	0.0000 (10)	−0.0058 (9)
C12	0.0247 (12)	0.0260 (12)	0.0257 (12)	0.0101 (10)	−0.0090 (9)	−0.0118 (9)
C13	0.0249 (12)	0.0246 (11)	0.0169 (10)	0.0137 (9)	−0.0039 (9)	−0.0047 (8)

Geometric parameters (Å, º) top

Br1—C2	1.890 (2)	C3—H3	0.9500
Cu1—O1	1.905 (1)	C4—C5	1.367 (3)
Cu1—O1ⁱ	1.905 (1)	C5—C6	1.415 (3)
Cu1—N1ⁱ	1.963 (2)	C5—H5	0.9500
Cu1—N1	1.963 (2)	C6—C7	1.436 (3)
Cl1—C4	1.744 (2)	C7—H7	0.9500
S1—O3	1.4297 (15)	C8—C9	1.391 (3)
S1—O2	1.4309 (16)	C8—C13	1.393 (3)
S1—N2	1.6945 (19)	C9—C10	1.387 (3)
S1—C8	1.756 (2)	C9—H9	0.9500
O1—C1	1.306 (2)	C10—C11	1.393 (3)
N1—C7	1.296 (3)	C10—H10	0.9500
N1—N2	1.437 (2)	C11—C12	1.376 (4)
N2—H2N	0.88 (1)	C11—H11	0.9500
C1—C6	1.418 (3)	C12—C13	1.390 (3)
C1—C2	1.421 (3)	C12—H12	0.9500
C2—C3	1.377 (3)	C13—H13	0.9500
C3—C4	1.395 (3)

O1—Cu1—O1ⁱ	180.000 (1)	C5—C4—Cl1	119.90 (16)
O1—Cu1—N1	91.28 (6)	C3—C4—Cl1	119.02 (15)
O1—Cu1—N1ⁱ	88.72 (6)	C4—C5—C6	120.01 (19)
O1ⁱ—Cu1—N1ⁱ	91.28 (6)	C4—C5—H5	120.0
O1ⁱ—Cu1—N1	88.72 (6)	C6—C5—H5	120.0
N1ⁱ—Cu1—N1	180.0	C5—C6—C1	120.83 (18)
O3—S1—O2	120.99 (10)	C5—C6—C7	116.47 (18)
O3—S1—N2	104.25 (9)	C1—C6—C7	122.65 (18)
O2—S1—N2	105.94 (9)	N1—C7—C6	124.48 (19)
O3—S1—C8	110.55 (10)	N1—C7—H7	117.8
O2—S1—C8	109.09 (10)	C6—C7—H7	117.8
N2—S1—C8	104.59 (10)	C9—C8—C13	121.3 (2)
C1—O1—Cu1	128.38 (13)	C9—C8—S1	118.74 (16)
C7—N1—N2	114.29 (17)	C13—C8—S1	119.62 (17)
C7—N1—Cu1	126.86 (14)	C10—C9—C8	119.2 (2)
N2—N1—Cu1	118.75 (12)	C10—C9—H9	120.4
N1—N2—S1	112.10 (13)	C8—C9—H9	120.4
N1—N2—H2N	107.8 (18)	C9—C10—C11	119.9 (2)
S1—N2—H2N	103.9 (18)	C9—C10—H10	120.1
O1—C1—C6	124.07 (18)	C11—C10—H10	120.1
O1—C1—C2	119.77 (18)	C12—C11—C10	120.3 (2)
C6—C1—C2	116.16 (18)	C12—C11—H11	119.9
C3—C2—C1	122.80 (19)	C10—C11—H11	119.9
C3—C2—Br1	119.33 (15)	C11—C12—C13	120.9 (2)
C1—C2—Br1	117.84 (15)	C11—C12—H12	119.5
C2—C3—C4	119.11 (18)	C13—C12—H12	119.5
C2—C3—H3	120.4	C12—C13—C8	118.4 (2)
C4—C3—H3	120.4	C12—C13—H13	120.8
C5—C4—C3	121.08 (19)	C8—C13—H13	120.8

N1ⁱ—Cu1—O1—C1	163.78 (17)	C4—C5—C6—C7	177.20 (19)
N1—Cu1—O1—C1	−16.22 (17)	O1—C1—C6—C5	−179.35 (19)
O1—Cu1—N1—C7	11.64 (18)	C2—C1—C6—C5	0.6 (3)
O1ⁱ—Cu1—N1—C7	−168.36 (18)	O1—C1—C6—C7	3.4 (3)
O1—Cu1—N1—N2	−164.50 (14)	C2—C1—C6—C7	−176.57 (19)
O1ⁱ—Cu1—N1—N2	15.50 (14)	N2—N1—C7—C6	173.81 (18)
C7—N1—N2—S1	−84.65 (18)	Cu1—N1—C7—C6	−2.5 (3)
Cu1—N1—N2—S1	91.96 (14)	C5—C6—C7—N1	174.74 (19)
O3—S1—N2—N1	−169.59 (13)	C1—C6—C7—N1	−7.9 (3)
O2—S1—N2—N1	61.73 (15)	O3—S1—C8—C9	−169.03 (17)
C8—S1—N2—N1	−53.47 (15)	O2—S1—C8—C9	−33.7 (2)
Cu1—O1—C1—C6	11.6 (3)	N2—S1—C8—C9	79.30 (19)
Cu1—O1—C1—C2	−168.43 (14)	O3—S1—C8—C13	17.7 (2)
O1—C1—C2—C3	179.09 (19)	O2—S1—C8—C13	153.05 (17)
C6—C1—C2—C3	−0.9 (3)	N2—S1—C8—C13	−93.98 (19)
O1—C1—C2—Br1	0.9 (3)	C13—C8—C9—C10	0.9 (3)
C6—C1—C2—Br1	−179.07 (14)	S1—C8—C9—C10	−172.22 (17)
C1—C2—C3—C4	0.7 (3)	C8—C9—C10—C11	−0.1 (3)
Br1—C2—C3—C4	178.82 (15)	C9—C10—C11—C12	−1.1 (3)
C2—C3—C4—C5	−0.2 (3)	C10—C11—C12—C13	1.4 (4)
C2—C3—C4—Cl1	179.83 (16)	C11—C12—C13—C8	−0.5 (4)
C3—C4—C5—C6	−0.1 (3)	C9—C8—C13—C12	−0.6 (3)
Cl1—C4—C5—C6	179.93 (15)	S1—C8—C13—C12	172.46 (18)
C4—C5—C6—C1	−0.2 (3)

Symmetry code: (i) −x+1, −y+1, −z+1.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2N···O1ⁱ	0.88 (1)	2.07 (2)	2.722 (2)	130 (2)

Symmetry code: (i) −x+1, −y+1, −z+1.

Experimental details

Crystal data
Chemical formula	[Cu(C₁₃H₉BrClN₂O₃S)₂]
M_r	840.82
Crystal system, space group	Triclinic, P1
Temperature (K)	100
a, b, c (Å)	8.0688 (1), 8.2755 (1), 11.7386 (2)
α, β, γ (°)	95.955 (1), 90.133 (1), 115.159 (1)
V (Å³)	704.70 (2)
Z	1
Radiation type	Mo Kα
µ (mm⁻¹)	4.00
Crystal size (mm)	0.20 × 0.09 × 0.09

Data collection
Diffractometer	Bruker SMART APEX diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.502, 0.715
No. of measured, independent and observed [I > 2σ(I)] reflections	8995, 3214, 2928
R_int	0.017
(sin θ/λ)_max (Å⁻¹)	0.649

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.021, 0.061, 1.05
No. of reflections	3214
No. of parameters	200
No. of restraints	1
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.52, −0.29

Computer programs: APEX2 (Bruker, 2007), SAINT (Bruker, 2007), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), X-SEED (Barbour, 2001), publCIF (Westrip, 2008).

Selected geometric parameters (Å, º) top

Cu1—O1	1.905 (1)	Cu1—N1	1.963 (2)

O1—Cu1—N1	91.28 (6)	O1—Cu1—N1ⁱ	88.72 (6)

Symmetry code: (i) −x+1, −y+1, −z+1.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2N···O1ⁱ	0.88 (1)	2.07 (2)	2.722 (2)	130 (2)

Symmetry code: (i) −x+1, −y+1, −z+1.

Acknowledgements

We thank the Science Fund (12-02-03-2031, 12-02-03-2051) and the University of Malaya (PJP) for supporting this study. We are grateful to the University of Malaya for the purchase of the diffractometer.

References

Ali, H. M., Yusnita, J., Rizal, M. R. & Ng, S. W. (2007). Acta Cryst. E63, m2937. Web of Science CSD CrossRef IUCr Journals Google Scholar
Barbour, L. J. (2001). J. Supramol. Chem. 1, 189–191. CrossRef CAS Google Scholar
Bruker (2007). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Sheldrick, G. M. (1996). SADABS. University of Göttingen, Germany. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Westrip, S. P. (2008). publCIF. In preparation. Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 64| Part 8| August 2008| Page m1039

doi:10.1107/S1600536808022022

Open

access

Format		BIBTeX
		EndNote
		RefMan
		Refer
		Medline
		CIF
		SGML
		Plain Text

Format		BIBTeX
		EndNote
		RefMan
		Refer
		Medline
		CIF
		SGML
		Plain Text

Search IUCr Journals		doi		Advanced search
Author		volume	page

metal-organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)