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Acta Cryst. (2007). E63, m2600    [ doi:10.1107/S1600536807046089 ]

Diaquabis(saccharinato-[kappa]N)copper(II)

F. Adam, I. A. Hassan, M. M. Rosli and H.-K. Fun

Abstract top

In the title compound, [Cu(C7H4NO3S)2(H2O)2], the CuII atom lies on a crystallographic inversion centre and is in a square-planar coordination geometry. The saccharinate ligand is essentially planar and the crystal structure is stabilized by intermolecular O-H...O and C-H...O interactions.

Comment top

Saccharin (or O-sulphobenzoimide) is widely used as an artificial sweetening agent. The chemistry of saccharin has attracted attention because of its suspected carcinogenous nature (Suzuki & Suzuki, 1995; Zurlo & Squire, 1998). Saccharin, its derivatives and some metal saccharinates are found to be enzymatic inhibitors (Groutas et al., 1996). Saccharin itself does not coordinate metal ions, but its deprotonated form (saccharinate) interacts with trace elements in human body and readily forms complexes with a large number of metal ions (Baran, 2005). The saccharinate anion acts as a polyfunctional ligand and may bond to metals by means of its imino nitrogen, carbonyl oxygen, or sulfonyl oxygen atoms, exhibiting different coordination modes such as monodentate (through the N-or the carbonyl O-atom), bidentate (N, O), tridentate (N, O, O) or as bridging ligand (Baran & Yilmaz, 2006). Our current interest in the chemistry of copper complexes with saccharin is because of its potential as a chiral specific catalyst. Our investigation has resulted in the synthesis of a unique square planar copper-saccharin complex in which the N—Cu—N and O—Cu—O angles (from water) are uniquely 180°. We report herein the crystal structure of disaquabis(Saccharinato-κN)Copper(II).

The CuII atom of the title complex lies on an inversion centre and is coordinated in a square-planar mode by two saccharinate (sac) ligands and two water molecules (Fig. 1). All bond lengths and angles in normal ranges (Allen et al., 1987). The sac ligand is essentially planar with the maximum deviation is 0.035Å for atom S1.

The H atoms of the water molecules participate in both intra and intermolecular hydrogen bonding with the carbonyl and sulfonyl O atoms of the sac ligand (Table 1, Fig. 2). Intermolecular O1W-H1W1···O3ii interactions link molecules into one-dimensional chains along the b axis and these chains are stacked along the a axis by C4—H4A···O2iii, C5- H5A···O1iv interactions [symmetry codes as in Table 1] and Cu···O short contacts [Cu1···O1(1 + x, y, z) = 2.488 Å] (Fig. 3).

Related literature top

For a related crystal structure, see: Yilmaz et al., (2001). For general background, see: Allen et al. (1987); Baran (2005); Baran & Yilmaz (2006); Groutas et al. (1996); Suzuki & Suzuki, (1995); Zurlo & Squire (1998).

Experimental top

To a solution of saccharin (0.732 g, 4 mmol) in 95% ethanol (20 ml), copper(II) nitrate (0.4832 g, 2 mmol) in ethanol (10 ml) was added, followed by triethylamine (0.5 ml, 3.6 mmol). The mixture was refluxed with stirring for 3 h. The resulting blue solution was filtered and left to evaporate slowly at room temperature. Blue needle-shaped single crystals suitable for X-ray diffraction were obtained after one week. Analysis found: C 36.21, H 2.28, N 6.67%; calculated: C 36.25, H 2.61, N 6.04%.

Refinement top

All C-bound H atoms were placed in calculated positions with C—H = 0.93Å and refined as riding, with Uiso(H) = 1.2Ueq(C). The H atoms for water molecules were located in a difference map and freely refined.

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, 1998); program(s) used to refine structure: SHELXTL (Sheldrick, 1998); molecular graphics: SHELXTL (Sheldrick, 1998); software used to prepare material for publication: SHELXTL (Sheldrick, 1998), PARST (Nardelli, 1995) and PLATON (Spek, 2003).

Figures top
[Figure 1] Fig. 1. The molecular structure showing 50% probability displacement ellipsoids and the atomic numbering [symmetry code: A, −x − 1, −y, −z]
[Figure 2] Fig. 2. The crystal packing viewed along the a axis. Hydrogen bonds are shown as dashed lines.
[Figure 3] Fig. 3. Packing viewed along the b axis, showing an extended chain along the a axis. Dashed lines denote Cu···O short contacts.
Diaquabis(saccharinato-κN)copper(II) top
Crystal data top
[Cu(C7H4NO3S)2(H2O)2]Z = 1
Mr = 463.92F000 = 235
Triclinic, P1Dx = 1.970 Mg m−3
Hall symbol: -P 1Mo Kα radiation
λ = 0.71073 Å
a = 4.9171 (1) ÅCell parameters from 14734 reflections
b = 7.8826 (2) Åθ = 2.7–37.5º
c = 10.5731 (3) ŵ = 1.72 mm−1
α = 96.167 (1)ºT = 100.0 (1) K
β = 102.295 (1)ºBlock, blue
γ = 99.211 (1)º0.74 × 0.13 × 0.09 mm
V = 390.968 (17) Å3
Data collection top
Bruker SMART APEXII CCD area-detector
diffractometer		3411 independent reflections
Radiation source: fine-focus sealed tube2975 reflections with I > 2σ(I)
Monochromator: graphiteRint = 0.029
Detector resolution: 8.33 pixels mm-1θmax = 35.0º
T = 100.0(1) Kθmin = 2.7º
ω scansh = −7→7
Absorption correction: multi-scan
(SADABS; Bruker, 2005)		k = −12→12
Tmin = 0.362, Tmax = 0.861l = −17→16
12980 measured reflections
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.027H atoms treated by a mixture of
independent and constrained refinement
wR(F2) = 0.080  w = 1/[σ2(Fo2) + (0.0421P)2 + 0.1186P]
where P = (Fo2 + 2Fc2)/3
S = 1.12(Δ/σ)max < 0.001
3411 reflectionsΔρmax = 0.61 e Å−3
133 parametersΔρmin = −0.63 e Å−3
Primary atom site location: structure-invariant direct methodsExtinction correction: none
Crystal data top
[Cu(C7H4NO3S)2(H2O)2]γ = 99.211 (1)º
Mr = 463.92V = 390.968 (17) Å3
Triclinic, P1Z = 1
a = 4.9171 (1) ÅMo Kα
b = 7.8826 (2) ŵ = 1.72 mm−1
c = 10.5731 (3) ÅT = 100.0 (1) K
α = 96.167 (1)º0.74 × 0.13 × 0.09 mm
β = 102.295 (1)º
Data collection top
Bruker SMART APEXII CCD area-detector
diffractometer		3411 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2005)		2975 reflections with I > 2σ(I)
Tmin = 0.362, Tmax = 0.861Rint = 0.029
12980 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.027133 parameters
wR(F2) = 0.080H atoms treated by a mixture of
independent and constrained refinement
S = 1.12Δρmax = 0.61 e Å−3
3411 reflectionsΔρmin = −0.63 e Å−3
Special details top

Experimental. The 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
xyzUiso*/Ueq
Cu1−0.50000.00000.00000.00928 (6)
S1−0.16480 (6)0.00582 (4)−0.23237 (3)0.00896 (6)
O10.03679 (19)−0.08789 (12)−0.16235 (10)0.01210 (16)
O2−0.3837 (2)−0.09943 (12)−0.33636 (10)0.01312 (17)
O3−0.3156 (2)0.40733 (12)−0.07145 (10)0.01392 (17)
O1W−0.4091 (2)−0.22110 (13)−0.05806 (11)0.01448 (18)
N1−0.2966 (2)0.11832 (13)−0.12802 (11)0.01013 (17)
C10.0086 (2)0.18416 (15)−0.28886 (12)0.01025 (19)
C20.1765 (3)0.18638 (16)−0.37910 (12)0.0119 (2)
H2A0.21720.0850−0.41810.014*
C30.2806 (3)0.34929 (17)−0.40792 (13)0.0139 (2)
H3A0.39280.3571−0.46840.017*
C40.2201 (3)0.50066 (17)−0.34815 (13)0.0143 (2)
H4A0.29410.6075−0.36880.017*
C50.0504 (3)0.49440 (16)−0.25788 (13)0.0132 (2)
H5A0.00910.5953−0.21830.016*
C6−0.0548 (2)0.33242 (15)−0.22911 (12)0.01049 (19)
C7−0.2353 (2)0.29281 (16)−0.13564 (12)0.01059 (19)
H1W1−0.467 (7)−0.301 (4)−0.018 (3)0.051 (8)*
H2W1−0.259 (5)−0.232 (3)−0.067 (2)0.030 (6)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cu10.01117 (10)0.00630 (9)0.01183 (10)0.00185 (6)0.00573 (7)0.00140 (7)
S10.01026 (12)0.00659 (12)0.01066 (13)0.00134 (8)0.00412 (9)0.00103 (9)
O10.0129 (4)0.0100 (4)0.0151 (4)0.0039 (3)0.0049 (3)0.0036 (3)
O20.0142 (4)0.0107 (4)0.0128 (4)−0.0002 (3)0.0029 (3)−0.0009 (3)
O30.0180 (4)0.0090 (4)0.0169 (4)0.0031 (3)0.0087 (3)0.0010 (3)
O1W0.0173 (4)0.0094 (4)0.0205 (5)0.0036 (3)0.0114 (3)0.0031 (3)
N10.0124 (4)0.0076 (4)0.0118 (4)0.0023 (3)0.0059 (3)0.0007 (3)
C10.0114 (4)0.0083 (5)0.0112 (5)0.0011 (3)0.0034 (4)0.0016 (4)
C20.0129 (5)0.0108 (5)0.0125 (5)0.0019 (4)0.0045 (4)0.0017 (4)
C30.0150 (5)0.0137 (5)0.0137 (5)0.0006 (4)0.0058 (4)0.0032 (4)
C40.0176 (5)0.0111 (5)0.0151 (5)0.0004 (4)0.0065 (4)0.0034 (4)
C50.0153 (5)0.0088 (5)0.0158 (5)0.0011 (4)0.0054 (4)0.0019 (4)
C60.0114 (5)0.0085 (5)0.0121 (5)0.0017 (3)0.0040 (4)0.0015 (4)
C70.0115 (5)0.0092 (5)0.0116 (5)0.0019 (3)0.0036 (4)0.0021 (4)
Geometric parameters (Å, °) top
Cu1—O1Wi1.9366 (10)C1—C61.3800 (17)
Cu1—O1W1.9366 (10)C1—C21.3878 (17)
Cu1—N1i2.0618 (10)C2—C31.3943 (17)
Cu1—N12.0619 (10)C2—H2A0.9300
S1—O21.4387 (10)C3—C41.394 (2)
S1—O11.4546 (10)C3—H3A0.9300
S1—N11.6438 (11)C4—C51.3949 (18)
S1—C11.7532 (12)C4—H4A0.9300
O3—C71.2363 (16)C5—C61.3891 (17)
O1W—H1W10.84 (3)C5—H5A0.9300
O1W—H2W10.78 (3)C6—C71.4875 (17)
N1—C71.3750 (16)
O1Wi—Cu1—O1W180.0C2—C1—S1129.07 (10)
O1Wi—Cu1—N1i90.97 (4)C1—C2—C3116.20 (12)
O1W—Cu1—N1i89.03 (4)C1—C2—H2A121.9
O1Wi—Cu1—N189.03 (4)C3—C2—H2A121.9
O1W—Cu1—N190.97 (4)C4—C3—C2121.47 (12)
N1i—Cu1—N1179.999 (1)C4—C3—H3A119.3
O2—S1—O1114.97 (6)C2—C3—H3A119.3
O2—S1—N1111.85 (6)C3—C4—C5121.06 (11)
O1—S1—N1109.84 (6)C3—C4—H4A119.5
O2—S1—C1110.82 (6)C5—C4—H4A119.5
O1—S1—C1111.27 (6)C6—C5—C4117.75 (12)
N1—S1—C196.63 (6)C6—C5—H5A121.1
Cu1—O1W—H1W1113 (2)C4—C5—H5A121.1
Cu1—O1W—H2W1123.5 (19)C1—C6—C5120.30 (11)
H1W1—O1W—H2W1108 (3)C1—C6—C7112.00 (10)
C7—N1—S1110.67 (8)C5—C6—C7127.70 (11)
C7—N1—Cu1127.87 (8)O3—C7—N1124.73 (11)
S1—N1—Cu1121.35 (6)O3—C7—C6122.43 (11)
C6—C1—C2123.22 (11)N1—C7—C6112.83 (10)
C6—C1—S1107.69 (9)
O2—S1—N1—C7−111.62 (9)C1—C2—C3—C40.51 (19)
O1—S1—N1—C7119.47 (9)C2—C3—C4—C5−0.6 (2)
C1—S1—N1—C73.99 (9)C3—C4—C5—C60.4 (2)
O2—S1—N1—Cu171.93 (8)C2—C1—C6—C5−0.06 (19)
O1—S1—N1—Cu1−56.99 (8)S1—C1—C6—C5−178.70 (10)
C1—S1—N1—Cu1−172.47 (7)C2—C1—C6—C7−179.28 (11)
O1Wi—Cu1—N1—C78.84 (10)S1—C1—C6—C72.09 (13)
O1W—Cu1—N1—C7−171.16 (10)C4—C5—C6—C1−0.02 (19)
O1Wi—Cu1—N1—S1−175.36 (7)C4—C5—C6—C7179.06 (12)
O1W—Cu1—N1—S14.64 (7)S1—N1—C7—O3177.59 (10)
O2—S1—C1—C6112.89 (9)Cu1—N1—C7—O3−6.24 (18)
O1—S1—C1—C6−117.86 (9)S1—N1—C7—C6−3.34 (13)
N1—S1—C1—C6−3.53 (10)Cu1—N1—C7—C6172.83 (8)
O2—S1—C1—C2−65.64 (13)C1—C6—C7—O3179.78 (12)
O1—S1—C1—C263.60 (13)C5—C6—C7—O30.6 (2)
N1—S1—C1—C2177.93 (12)C1—C6—C7—N10.69 (15)
C6—C1—C2—C3−0.18 (18)C5—C6—C7—N1−178.46 (12)
S1—C1—C2—C3178.15 (10)
Symmetry codes: (i) −x−1, −y, −z.
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
O1W—H1W1···O3ii0.84 (3)2.57 (3)3.0298 (14)116 (3)
O1W—H1W1···O3i0.84 (3)1.75 (3)2.5392 (14)156 (3)
O1W—H2W1···O10.78 (3)2.18 (2)2.7689 (14)132 (2)
C4—H4A···O2iii0.932.533.4050 (17)157
C5—H5A···O1iv0.932.483.3542 (16)157
Symmetry codes: (ii) x, y−1, z; (i) −x−1, −y, −z; (iii) x+1, y+1, z; (iv) x, y+1, z.
Table 1
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
O1W—H1W1···O3i0.84 (3)2.57 (3)3.0298 (14)116 (3)
O1W—H1W1···O3ii0.84 (3)1.75 (3)2.5392 (14)156 (3)
O1W—H2W1···O10.78 (3)2.18 (2)2.7689 (14)132 (2)
C4—H4A···O2iii0.932.533.4050 (17)157
C5—H5A···O1iv0.932.483.3542 (16)157
Symmetry codes: (i) x, y−1, z; (ii) −x−1, −y, −z; (iii) x+1, y+1, z; (iv) x, y+1, z.
Acknowledgements top

The authors wish to thank the Ministry of Education, Malaysia (FRGS grant No. 203/PKIMIA/671021) and Universiti Sains Malaysia (short-term research grant No. 304/PKIMIA/638055) for supporting this work. The University of Khartoum, Sudan is acknowledged for providing a scholarship to I. A. Hassan.

references
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