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Acta Cryst. (2008). E64, m708    [ doi:10.1107/S1600536808010799 ]

Poly[bis([mu]2-benzyloxyacetato-[kappa]3O,O':O'')cadmium(II)]

J.-W. Liu and S. W. Ng

Abstract top

The title cadmium derivative of benzyloxyacetic acid, [Cd(C9H9O3)2]n, exists as a [mu]2-carboxylate-bridged layer network. Two benzyloxyacetate units each chelate the metal through a carboxylate as well as through the ether O atoms; the metal is also coordinated by the double-bond carbonyl O atom of two adjacent benzyloxyacetate units in an octahedral geometry. The metal atom lies on a special position of 2 site symmetry. The phenyl group is disordered equally over two positions.

Comment top

The crystal structures of a large number of metal derivatives of aryloxyacetic acids have been reported; in some structures, the ether oxygen also engages in bonding so that the carboxylate unit functions both as a chelate as well as a bridge. The cadmium derivative of phenyoxyacetic acid exists as a diaqua, carboxylate-chelated compound. The carboxyl –CO2 portion engages in chelation instead (Mak et al., 1985). The title cadmium analog has a benzyl group in place of the phenyl group, which is probably less crowded; this feature permits the ether linkage to bind to the metal atom. The compound (Scheme I) is an anhydrous compound; the carboxylate group chelates to the metal atom. It also bridges adjacent metal atoms (Fig. 1); the bridges lead to the formation of a layer motif (Fig. 2).

Related literature top

There are no crystallographic examples of metal benzyloxyacetates although there are many examples of metal aryloxyacetates. For mononuclear diaquadi(phenoxyacetato)cadmium, see: Mak et al. (1985).

Experimental top

Cadmium dinitrate tetrahydrate (0.31 g, 1 mmol) and 2,2'-bipyridine (0.16 g, 1 mmol) were added to a hot aqueous solution of benzyloxyacetic acid (0.17 g, 1 mmol). The pH of the solution was adjusted to 6 with 0.1 M sodium hydroxide. The solution was allowed to evaporate at room temperature. Colorless single crystals are separated from the filtered solution after several days.

Refinement top

Hydrogen atoms were treated as riding, with C–H = 0.93 to 0.97 Å and were included in the refinement with U(H) set to 1.2 times Ueq(C). The phenyl ring is disordered over two sites; the occupancy could not be refined, and each component was arbitrarily assigned 0.5 occupancy. The ring was refined as a rigid hexagon; the temperature factors of the primed atoms were constrained to those of the unprimed ones. The anisotropic temperature factors of the ring were retrained to be nearly isotropic. The C3–C4 and C3–C4' distances were restrained to within 0.01 Å of each other.

The final difference Fourier map had a large peak at about 1 Å from Cd1.

Computing details top

Data collection: APEX2 (Bruker, 2006); cell refinement: SAINT (Bruker, 2006); data reduction: SAINT (Bruker, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001); OLEX (Dolomanov et al., 2003); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. Thermal displacement ellipsoid plot (Barbour, 2001) illustrating the coordination geometry of Cd in [Cd(C9H9O3)2]n. Displacement ellipsoids are drawn at the 50% probability level and H atoms as spheres of arbitrary radii.
[Figure 2] Fig. 2. OLEX (Dolomanov et al., 2003) representation of the layer structure.
Poly[bis(µ2-benzyloxyacetato-κ3O,O':\<i>O'')cadmium(II)] top
Crystal data top
[Cd(C9H9O3)2]F000 = 444
Mr = 442.72Dx = 1.575 Mg m−3
Orthorhombic, P21212Mo Kα radiation
λ = 0.71073 Å
Hall symbol: P 2 2abCell parameters from 2270 reflections
a = 6.7430 (2) Åθ = 2.6–23.6º
b = 8.9449 (2) ŵ = 1.20 mm−1
c = 15.4736 (4) ÅT = 295 (2) K
V = 933.30 (4) Å3Block, colorless
Z = 20.33 × 0.13 × 0.04 mm
Data collection top
Bruker APEXII
diffractometer		1639 independent reflections
Radiation source: fine-focus sealed tube1483 reflections with I > 2σ(I)
Monochromator: graphiteRint = 0.039
T = 295(2) Kθmax = 25.0º
φ and ω scansθmin = 1.3º
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)		h = −7→7
Tmin = 0.693, Tmax = 0.954k = −10→9
5780 measured reflectionsl = −18→17
Refinement top
Refinement on F2Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: fullH-atom parameters constrained
R[F2 > 2σ(F2)] = 0.044  w = 1/[σ2(Fo2) + (0.0833P)2]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.125(Δ/σ)max = 0.001
S = 1.09Δρmax = 2.22 e Å−3
1639 reflectionsΔρmin = −0.88 e Å−3
108 parametersExtinction correction: none
37 restraintsAbsolute structure: Flack (1983), 501 Friedel pairs
Primary atom site location: structure-invariant direct methodsFlack parameter: 0.03 (8)
Secondary atom site location: difference Fourier map
Crystal data top
[Cd(C9H9O3)2]V = 933.30 (4) Å3
Mr = 442.72Z = 2
Orthorhombic, P21212Mo Kα
a = 6.7430 (2) ŵ = 1.20 mm−1
b = 8.9449 (2) ÅT = 295 (2) K
c = 15.4736 (4) Å0.33 × 0.13 × 0.04 mm
Data collection top
Bruker APEXII
diffractometer		1639 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)		1483 reflections with I > 2σ(I)
Tmin = 0.693, Tmax = 0.954Rint = 0.039
5780 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.044H-atom parameters constrained
wR(F2) = 0.125Δρmax = 2.22 e Å−3
S = 1.09Δρmin = −0.88 e Å−3
1639 reflectionsAbsolute structure: Flack (1983), 501 Friedel pairs
108 parametersFlack parameter: 0.03 (8)
37 restraints
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
Cd11.00001.00000.01184 (4)0.0405 (3)
O11.2315 (7)0.8208 (5)0.0358 (3)0.0481 (12)
O21.2948 (7)0.5938 (5)0.0869 (3)0.0495 (12)
O30.9048 (6)0.8466 (5)0.1304 (3)0.0443 (11)
C11.1913 (10)0.7127 (7)0.0819 (4)0.0385 (15)
C21.0100 (14)0.7103 (6)0.1367 (4)0.0427 (13)
H2A0.92480.62870.11860.051*
H2B1.04720.69310.19640.051*
C30.7017 (11)0.8363 (9)0.1615 (5)0.059 (2)
H3A0.64230.74630.13810.070*
H3B0.62760.92090.13920.070*
C40.680 (3)0.834 (2)0.2552 (5)0.060 (3)0.50
C50.567 (2)0.7180 (17)0.2895 (9)0.100 (5)0.50
H50.50610.64940.25290.119*0.50
C60.545 (3)0.705 (2)0.3785 (10)0.124 (6)0.50
H60.46890.62760.40140.149*0.50
C70.636 (3)0.807 (2)0.4332 (5)0.127 (8)0.50
H70.62060.79860.49270.152*0.50
C80.749 (4)0.923 (2)0.3989 (9)0.135 (5)0.50
H80.80960.99150.43550.162*0.50
C90.771 (4)0.936 (2)0.3099 (10)0.108 (5)0.50
H90.84681.01330.28700.130*0.50
C4'0.704 (3)0.8030 (19)0.2550 (5)0.060 (3)0.50
C5'0.682 (3)0.6579 (16)0.2856 (9)0.100 (5)0.50
H5'0.66020.57980.24710.119*0.50
C6'0.691 (3)0.6296 (17)0.3739 (10)0.124 (6)0.50
H6'0.67550.53250.39430.149*0.50
C7'0.723 (3)0.746 (2)0.4315 (6)0.127 (8)0.50
H7'0.72880.72730.49050.152*0.50
C8'0.745 (4)0.891 (2)0.4009 (9)0.135 (5)0.50
H8'0.76670.96950.43950.162*0.50
C9'0.736 (4)0.9198 (16)0.3127 (10)0.108 (5)0.50
H9'0.75141.01680.29220.130*0.50
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cd10.0336 (4)0.0237 (3)0.0641 (4)0.0012 (3)0.0000.000
O10.041 (3)0.033 (3)0.070 (3)0.010 (2)0.012 (2)0.006 (3)
O20.048 (3)0.030 (2)0.070 (3)0.010 (2)0.006 (2)0.003 (2)
O30.037 (2)0.028 (2)0.068 (3)0.0084 (19)0.012 (2)0.008 (2)
C10.036 (4)0.027 (3)0.053 (4)0.006 (3)−0.003 (3)−0.005 (3)
C20.037 (3)0.028 (3)0.063 (3)0.007 (4)−0.006 (6)0.004 (2)
C30.033 (4)0.056 (4)0.087 (6)0.016 (4)0.015 (4)0.008 (4)
C40.054 (6)0.054 (6)0.072 (5)0.009 (6)0.014 (4)−0.012 (4)
C50.109 (10)0.098 (9)0.092 (7)0.006 (7)0.031 (7)0.016 (7)
C60.126 (11)0.126 (9)0.120 (8)−0.006 (8)0.019 (8)0.020 (8)
C70.132 (11)0.134 (11)0.114 (9)0.012 (9)0.018 (8)−0.004 (8)
C80.134 (9)0.152 (9)0.119 (8)−0.005 (8)−0.001 (7)−0.031 (7)
C90.091 (9)0.122 (8)0.112 (7)−0.008 (7)0.007 (6)−0.025 (6)
C4'0.054 (6)0.054 (6)0.072 (5)0.009 (6)0.014 (4)−0.012 (4)
C5'0.109 (10)0.098 (9)0.092 (7)0.006 (7)0.031 (7)0.016 (7)
C6'0.126 (11)0.126 (9)0.120 (8)−0.006 (8)0.019 (8)0.020 (8)
C7'0.132 (11)0.134 (11)0.114 (9)0.012 (9)0.018 (8)−0.004 (8)
C8'0.134 (9)0.152 (9)0.119 (8)−0.005 (8)−0.001 (7)−0.031 (7)
C9'0.091 (9)0.122 (8)0.112 (7)−0.008 (7)0.007 (6)−0.025 (6)
Geometric parameters (Å, °) top
Cd1—O12.268 (4)C5—C61.3900
Cd1—O1i2.268 (4)C5—H50.9300
Cd1—O2ii2.226 (5)C6—C71.3900
Cd1—O2iii2.226 (5)C6—H60.9300
Cd1—O32.379 (4)C7—C81.3900
Cd1—O3i2.379 (4)C7—H70.9300
O1—C11.232 (8)C8—C91.3900
O2—C11.274 (7)C8—H80.9300
O2—Cd1iv2.226 (5)C9—H90.9300
O3—C21.414 (7)C4'—C5'1.3900
O3—C31.455 (8)C4'—C9'1.3900
C1—C21.488 (11)C5'—C6'1.3900
C2—H2A0.9700C5'—H5'0.9300
C2—H2B0.9700C6'—C7'1.3900
C3—C41.457 (11)C6'—H6'0.9300
C3—C4'1.477 (11)C7'—C8'1.3900
C3—H3A0.9700C7'—H7'0.9300
C3—H3B0.9700C8'—C9'1.3900
C4—C51.3900C8'—H8'0.9300
C4—C91.3900C9'—H9'0.9300
O1—Cd1—O1i161.2 (3)H3A—C3—H3B107.5
O1—Cd1—O2ii105.9 (2)C5—C4—C9120.0
O1—Cd1—O2iii87.2 (2)C5—C4—C3116.6 (12)
O1—Cd1—O369.6 (2)C9—C4—C3123.4 (12)
O1—Cd1—O3i95.5 (2)C6—C5—C4120.0
O1i—Cd1—O2ii87.2 (2)C6—C5—H5120.0
O1i—Cd1—O2iii105.9 (2)C4—C5—H5120.0
O1i—Cd1—O3i69.6 (2)C5—C6—C7120.0
O1i—Cd1—O395.5 (2)C5—C6—H6120.0
O2ii—Cd1—O2iii93.3 (3)C7—C6—H6120.0
O2ii—Cd1—O398.3 (2)C6—C7—C8120.0
O2ii—Cd1—O3i156.2 (2)C6—C7—H7120.0
O2iii—Cd1—O3156.2 (2)C8—C7—H7120.0
O2iii—Cd1—O3i98.3 (2)C9—C8—C7120.0
O3—Cd1—O3i79.1 (2)C9—C8—H8120.0
C1—O1—Cd1119.9 (4)C7—C8—H8120.0
C1—O2—Cd1iv127.8 (5)C8—C9—C4120.0
C2—O3—C3113.3 (6)C8—C9—H9120.0
C2—O3—Cd1114.5 (4)C4—C9—H9120.0
C3—O3—Cd1123.1 (4)C5'—C4'—C9'120.0
O1—C1—O2124.7 (6)C5'—C4'—C3121.4 (12)
O1—C1—C2121.5 (5)C9'—C4'—C3118.6 (12)
O2—C1—C2113.8 (6)C6'—C5'—C4'120.0
O3—C2—C1111.1 (5)C6'—C5'—H5'120.0
O3—C2—H2A109.4C4'—C5'—H5'120.0
C1—C2—H2A109.4C5'—C6'—C7'120.0
O3—C2—H2B109.4C5'—C6'—H6'120.0
C1—C2—H2B109.4C7'—C6'—H6'120.0
H2A—C2—H2B108.0C6'—C7'—C8'120.0
O3—C3—C4115.1 (10)C6'—C7'—H7'120.0
O3—C3—C4'109.0 (11)C8'—C7'—H7'120.0
O3—C3—H3A108.5C9'—C8'—C7'120.0
C4—C3—H3A108.5C9'—C8'—H8'120.0
C4'—C3—H3A101.8C7'—C8'—H8'120.0
O3—C3—H3B108.5C8'—C9'—C4'120.0
C4—C3—H3B108.5C8'—C9'—H9'120.0
C4'—C3—H3B120.9C4'—C9'—H9'120.0
O2ii—Cd1—O1—C1−78.1 (6)Cd1—O3—C2—C115.2 (7)
O2iii—Cd1—O1—C1−170.7 (5)O1—C1—C2—O3−2.7 (10)
O1i—Cd1—O1—C154.5 (5)O2—C1—C2—O3178.2 (6)
O3i—Cd1—O1—C191.2 (6)C2—O3—C3—C476.0 (10)
O3—Cd1—O1—C115.0 (5)Cd1—O3—C3—C4−139.0 (9)
O2ii—Cd1—O3—C288.3 (5)C2—O3—C3—C4'64.4 (10)
O2iii—Cd1—O3—C2−29.9 (7)Cd1—O3—C3—C4'−150.7 (8)
O1i—Cd1—O3—C2176.3 (5)O3—C3—C4—C5−128.2 (12)
O1—Cd1—O3—C2−15.6 (4)C4'—C3—C4—C5−65 (6)
O3i—Cd1—O3—C2−115.7 (5)O3—C3—C4—C949.7 (12)
O2ii—Cd1—O3—C3−56.3 (6)C4'—C3—C4—C9113 (7)
O2iii—Cd1—O3—C3−174.5 (5)C3—C4—C5—C6178.0 (15)
O1i—Cd1—O3—C331.7 (5)C3—C4—C9—C8−177.8 (16)
O1—Cd1—O3—C3−160.2 (6)O3—C3—C4'—C5'−97.6 (15)
O3i—Cd1—O3—C399.7 (5)C4—C3—C4'—C5'141 (8)
Cd1—O1—C1—O2166.5 (5)O3—C3—C4'—C9'80.5 (10)
Cd1—O1—C1—C2−12.5 (9)C4—C3—C4'—C9'−41 (7)
Cd1iv—O2—C1—O1−25.2 (10)C3—C4'—C5'—C6'178.1 (17)
Cd1iv—O2—C1—C2153.9 (4)C3—C4'—C9'—C8'−178.1 (17)
C3—O3—C2—C1163.3 (6)
Symmetry codes: (i) −x+2, −y+2, z; (ii) x−1/2, −y+3/2, −z; (iii) −x+5/2, y+1/2, −z; (iv) x+1/2, −y+3/2, −z.
Table 1
Selected geometric parameters (Å, °) top
Cd1—O12.268 (4)Cd1—O2iii2.226 (5)
Cd1—O1i2.268 (4)Cd1—O32.379 (4)
Cd1—O2ii2.226 (5)Cd1—O3i2.379 (4)
O1—Cd1—O1i161.2 (3)O1i—Cd1—O395.5 (2)
O1—Cd1—O2ii105.9 (2)O2ii—Cd1—O2iii93.3 (3)
O1—Cd1—O2iii87.2 (2)O2ii—Cd1—O398.3 (2)
O1—Cd1—O369.6 (2)O2ii—Cd1—O3i156.2 (2)
O1—Cd1—O3i95.5 (2)O2iii—Cd1—O3156.2 (2)
O1i—Cd1—O2ii87.2 (2)O2iii—Cd1—O3i98.3 (2)
O1i—Cd1—O2iii105.9 (2)O3—Cd1—O3i79.1 (2)
O1i—Cd1—O3i69.6 (2)
Symmetry codes: (i) −x+2, −y+2, z; (ii) x−1/2, −y+3/2, −z; (iii) −x+5/2, y+1/2, −z.
Acknowledgements top

The authors thank Daqing Petroleum Institute and the University of Malaya for generously supporting this study.

references
References top

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