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Anhydrous polymeric zinc(II) penta­noate

aDepartment of Chemistry, University of the West Indies, Mona, Kingston 7, Jamaica
*Correspondence e-mail: henry.ellis@uwimona.edu.jm

(Received 10 March 2008; accepted 26 March 2008; online 7 June 2008)

The structure of the title compound, poly[di-μ-penta­noato-zinc(II)], [Zn{CH3(CH2)3COO}2]n, consists of a three-dimensional polymeric layered network with sheets parallel to the (100) plane, in which tetra­hedrally coordinated zinc(II) ions are connected by penta­noate bridges in a synanti arrangement. The hydro­carbon chains are in the fully extended all-trans conformation and are arranged in a tail-to-tail double bilayer.

Related literature

For related literature, see: Clegg et al. (1986[Clegg, W., Little, I. R. & Straughan, B. P. (1986). Acta Cryst. C42, 1701-1703.]); Blair et al. (1993[Blair, J., Howie, R. A. & Wardell, J. L. (1993). Acta Cryst. C49, 219-221.]); Dumbleton & Lomer (1965[Dumbleton, J. H. & Lomer, T. R. (1965). Acta Cryst. 19, 301-307.]); Glover (1981[Glover, D. M. (1981). Acta Cryst. A37, 251-263.]); Goldschmied et al. (1977[Goldschmied, E., Rae, A. D. & Stephenson, N. C. (1977). Acta Cryst. B33, 2117-2120.]); Ishioka et al. (1998[Ishioka, T., Shibata, Y., Takahasi, M. & Kenesaka, T. (1998). Spectrochim. Acta A, 54, 1811-1818.]); Lacouture et al. (2000[Lacouture, F., Peultier, J., François, M. & Steinmetz, J. (2000). Acta Cryst. C56, 556-557.]); Lewis & Lomer (1969[Lewis, E. L. V. & Lomer, T. R. (1969). Acta Cryst. B25, 702-710.]); Lomer & Perera (1974[Lomer, T. R. & Perera, K. (1974). Acta Cryst. B30, 2912-2913.]); Peultier et al. (1999[Peultier, J., Francois, M. & Steinmetz, J. (1999). Acta Cryst. C55, 2064-2065.]); Segedin et al. (1999[Segedin, N., Lah, Z. M., Leban, I. & Golic, L. (1999). Acta Chim. Slov. 46, 173-184.]).

[Scheme 1]

Experimental

Crystal data
  • [Zn(C5H9O2)2]

  • Mr = 267.63

  • Monoclinic, P 21 /a

  • a = 9.389 (2) Å

  • b = 4.7820 (10) Å

  • c = 29.126 (7) Å

  • β = 104.256 (7)°

  • V = 1267.5 (5) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 1.93 mm−1

  • T = 293 (2) K

  • 0.30 × 0.30 × 0.05 mm

Data collection
  • Rigaku R-AXIS IIC image-plate diffractometer

  • Absorption correction: multi-scan (CrystalClear; Rigaku, 2000[Rigaku (2000). CrystalClear. Rigaku Corporation, The Woodlands, Texas, USA.]) Tmin = 0.621, Tmax = 1.000 (expected range = 0.564–0.908)

  • 7493 measured reflections

  • 2125 independent reflections

  • 1965 reflections with I > 2σ(I)

  • Rint = 0.061

Refinement
  • R[F2 > 2σ(F2)] = 0.062

  • wR(F2) = 0.126

  • S = 1.17

  • 2125 reflections

  • 138 parameters

  • H-atom parameters constrained

  • Δρmax = 0.32 e Å−3

  • Δρmin = −0.52 e Å−3

Table 1
Selected geometric parameters (Å, °)

Zn1—O1 1.950 (3)
Zn1—O3 1.966 (3)
Zn1—O2i 1.947 (3)
Zn1—O4ii 1.963 (4)
O2i—Zn1—O1 107.80 (15)
O2i—Zn1—O4ii 112.66 (15)
O1—Zn1—O4ii 116.62 (17)
O2i—Zn1—O3 113.19 (15)
O1—Zn1—O3 100.89 (15)
O4ii—Zn1—O3 105.21 (14)
Symmetry codes: (i) x, y+1, z; (ii) [x+{\script{1\over 2}}, -y+{\script{1\over 2}}, z].

Data collection: CrystalClear (Rigaku, 2000[Rigaku (2000). CrystalClear. Rigaku Corporation, The Woodlands, Texas, USA.]); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SIR92 (Altomare et al., 1994[Altomare, A., Cascarano, G., Giacovazzo, C., Guagliardi, A., Burla, M. C., Polidori, G. & Camalli, M. (1994). J. Appl. Cryst. 27, 435.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: Mercury (Macrae et al., 2006[Macrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor, R., Towler, M. & van de Streek, J. (2006). J. Appl. Cryst. 39, 453-457.]) and DIAMOND (Bergerhoff et al., 1996[Bergerhoff, G., Berndt, M. & Brandenburg, K. (1996). DIAMOND. Crystal Impact GbR, Bonn, Germany.]); software used to prepare material for publication: SHELXL97.

Supporting information


Comment top

Long-chain metal carboxylates do not easily form crystals suitable for single-crystal X-ray analysis; usually, the crystals are thin needles that are fragile and, in many cases exhibit micro-twinning. Consequently, the few structures that have been reported are those of the short-chain homologues (Dumbleton & Lomer, 1965; Lewis & Lomer, 1969; Glover, 1981; Lomer & Perera, 1974; Ishioka et al., 1998). For the zinc(II) series those reported include anhydrous zinc(II) acetate (Clegg et al., 1986), propionate (Goldschmied et al., 1977), butanoate (Blair et al., 1993), hexanoate and heptanoate (Segedin et al., 1999; Peultier et al., 1999) and octanoate (Lacouture et al., 2000). The compounds are isostructural in the sense that the zinc ions have a tetrahedral geometry of oxygen atoms and are bridged by bidentate ligands. In this study, anhydrous zinc(II) pentanoate, (I), was investigated in order to elucidate its crystal structure.

The structure (Fig. 1) is four-coordinate, where each zinc ion is tetrahedrally coordinated by oxygen atoms from four different pentanoate ligands. The four pentanoate ligands around zinc are of the Z,E-type bridging bidentate mode; that is, they are bonded in a syn-anti arrangement to two tetrahedral zinc ions. Geometric data indicate that the Zn—O bond lengths are not equivalent and clearly point to unsymmetrical bonding around the zinc ion.

The alkyl chains of the pentanoate groups are in the fully extended all-trans conformation. There is excellent agreement of the C—C bond lengths and C—C—C angles with published values for hydrocarbon chains in a fully extended all-trans conformation (Lomer & Perera, 1974). There are four formula units in the unit cell and two distinct basal planes, resulting in a double bilayer lamella arrangement forming a polymeric network (Fig. 2) with an alternating packing of the hydrocarbon chains in neighbouring bilayers. When viewed down the b axis, the hydrocarbon chains, which are tilted with respect to the zinc basal planes, are in each bilayer aligned in different planes. The structure appears very different when viewed down the a axis (Fig. 3), where in one bilayer the chains appear to zigzag and cross at the bonds along the C—C axis. In the other bilayer the chains are tilted towards each other and appear to cross each other at carbon atom number 4.

The molecular packing (Fig. 4) highlights the distorted tetrahedra around the zinc ions. In one basal plane, the vertices of the tetrahedra alternate parallel and perpendicular to the vertical plane throughout and in the other basal plane the vertices alternate at the top and bottom throughout. This arrangement allows for alternating basal planes in the overall structure to be identical.

There is interaction between parallel sheets through bidentate bridging, resulting in a three-dimensional sheet-like/layered polymeric network where the chains are arranged tail-to-tail, arising from van der Waals interactions in sheets parallel to the ac plane.

Related literature top

For related literature, see: Clegg et al. (1986); Blair et al. (1993); Dumbleton & Lomer (1965); Glover (1981); Goldschmied et al. (1977); Ishioka et al. (1998); Lacouture et al. (2000); Lewis & Lomer (1969); Lomer & Perera (1974); Peultier et al. (1999); Segedin et al. (1999).

Experimental top

Single crystals of zinc(II) pentanoate were prepared from the reaction of zinc oxide (0.407 g) and n-pentanoic acid (5.0 cm3; >100% excess) in approximately 100 cm3 of ethanol. The white suspension was refluxed until the solution was transparent. The resulting hot, colorless solution was filtered by suction and the filtrate left to cool to room temperature. After about six days, long, thin, colourless, plate-like single crystals, some in clusters, crystallized from solution. The crystals were then removed, air-dried, and kept in sealed vials at ambient temperature.

Refinement top

H atoms were positioned geometrically and refined as riding, with C—H = 0.97 Å and Uiso(H) = 1.2Ueq(C) for methylene, and C—H = 0.96 Å and Uiso(H) = 1.5Ueq(C) for methyl groups. The crystal was weakly diffracting at high angles.

Computing details top

Data collection: CrystalClear (Rigaku, 2000); cell refinement: CrystalClear (Rigaku, 2000); data reduction: CrystalClear (Rigaku, 2000); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: Mercury (Macrae et al., 2006) and DIAMOND (Bergerhoff et al., 1996); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. : Asymmetric unit of zinc(II) n-pentanoate: Displacement ellipsoids are drawn at the 75% probability level.
[Figure 2] Fig. 2. : Projection down the b axis. Displacement ellipsoids are drawn at the 50% probability level.
[Figure 3] Fig. 3. : View down the a axis (hydrogen atoms omitted). Displacement ellipsoids are drawn at the 50% probability level.
[Figure 4] Fig. 4. : Unit-cell contents, showing alternating tetrahedra of oxygen atoms around zinc ions in the zinc basal planes.
poly[di-µ-pentanoato-zinc(II)] top
Crystal data top
[Zn(C5H9O2)2]Dx = 1.402 Mg m3
Mr = 267.63Melting point: 425.5 K
Monoclinic, P21/aMo Kα radiation, λ = 0.71073 Å
a = 9.389 (2) ÅCell parameters from 7493 reflections
b = 4.782 (1) Åθ = 2.2–25.0°
c = 29.126 (7) ŵ = 1.93 mm1
β = 104.256 (7)°T = 293 K
V = 1267.5 (5) Å3Thin block, colourless
Z = 40.30 × 0.30 × 0.05 mm
F(000) = 560
Data collection top
Rigaku R-AXIS IIC image-plate
diffractometer
2125 independent reflections
Radiation source: rotating-anode X-ray tube1965 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.062
Detector resolution: 105 pixels mm-1θmax = 25.0°, θmin = 2.2°
ϕ scansh = 1111
Absorption correction: multi-scan
(CrystalClear; Rigaku, 2000)
k = 55
Tmin = 0.621, Tmax = 1.000l = 3434
7493 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.062Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.126H-atom parameters constrained
S = 1.17 w = 1/[σ2(Fo2) + (0.0408P)2 + 3.0707P]
where P = (Fo2 + 2Fc2)/3
2125 reflections(Δ/σ)max < 0.001
138 parametersΔρmax = 0.32 e Å3
0 restraintsΔρmin = 0.52 e Å3
Crystal data top
[Zn(C5H9O2)2]V = 1267.5 (5) Å3
Mr = 267.63Z = 4
Monoclinic, P21/aMo Kα radiation
a = 9.389 (2) ŵ = 1.93 mm1
b = 4.782 (1) ÅT = 293 K
c = 29.126 (7) Å0.30 × 0.30 × 0.05 mm
β = 104.256 (7)°
Data collection top
Rigaku R-AXIS IIC image-plate
diffractometer
2125 independent reflections
Absorption correction: multi-scan
(CrystalClear; Rigaku, 2000)
1965 reflections with I > 2σ(I)
Tmin = 0.621, Tmax = 1.000Rint = 0.062
7493 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0620 restraints
wR(F2) = 0.126H-atom parameters constrained
S = 1.17Δρmax = 0.32 e Å3
2125 reflectionsΔρmin = 0.52 e Å3
138 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
xyzUiso*/Ueq
C10.7184 (5)0.3109 (10)0.19302 (17)0.0350 (10)
C20.7780 (6)0.1602 (11)0.15666 (19)0.0456 (13)
H2A0.86360.05440.17310.055*
H2B0.70470.02670.14070.055*
C30.8215 (6)0.3404 (11)0.11919 (19)0.0462 (13)
H3A0.89850.46890.13460.055*
H3B0.73740.45030.10290.055*
C40.8750 (7)0.1677 (13)0.0835 (2)0.0571 (15)
H4A0.95950.05910.10000.069*
H4B0.79830.03760.06860.069*
C50.9177 (9)0.3437 (17)0.0453 (2)0.081 (2)
H5A0.99460.47120.05990.122*
H5B0.95170.22330.02390.122*
H5C0.83380.44730.02820.122*
C60.4620 (5)0.1354 (11)0.29619 (18)0.0405 (12)
C70.5718 (6)0.0210 (14)0.3329 (2)0.0569 (16)
H7A0.65410.10240.34560.068*
H7B0.60850.17560.31760.068*
C80.5177 (7)0.1364 (17)0.3739 (2)0.0666 (18)
H8A0.46950.01250.38700.080*
H8B0.44500.28000.36210.080*
C90.6363 (9)0.258 (2)0.4128 (3)0.097 (3)
H9A0.71120.11680.42370.116*
H9B0.68170.41230.40010.116*
C100.5825 (11)0.362 (3)0.4546 (3)0.139 (4)
H10A0.53630.21090.46720.208*
H10B0.66420.43030.47870.208*
H10C0.51280.50990.44460.208*
O10.6932 (4)0.1838 (7)0.22800 (13)0.0486 (9)
O20.6954 (4)0.5724 (7)0.18803 (12)0.0438 (9)
O30.4976 (4)0.2344 (7)0.26038 (12)0.0431 (8)
O40.3333 (4)0.1625 (8)0.30100 (13)0.0480 (9)
Zn10.68833 (6)0.21140 (11)0.24407 (2)0.0358 (2)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.040 (3)0.031 (3)0.038 (3)0.000 (2)0.017 (2)0.001 (2)
C20.065 (4)0.032 (3)0.049 (3)0.004 (2)0.032 (3)0.000 (2)
C30.061 (4)0.035 (3)0.049 (3)0.001 (2)0.027 (3)0.006 (2)
C40.071 (4)0.058 (4)0.050 (3)0.000 (3)0.031 (3)0.001 (3)
C50.110 (6)0.092 (6)0.059 (4)0.004 (5)0.052 (4)0.008 (4)
C60.038 (3)0.037 (3)0.051 (3)0.001 (2)0.020 (2)0.004 (2)
C70.045 (3)0.077 (4)0.051 (3)0.011 (3)0.017 (3)0.018 (3)
C80.051 (4)0.093 (5)0.057 (4)0.003 (3)0.017 (3)0.022 (4)
C90.076 (5)0.144 (9)0.070 (5)0.010 (5)0.015 (4)0.047 (5)
C100.121 (9)0.214 (13)0.081 (6)0.009 (8)0.025 (6)0.073 (7)
O10.073 (3)0.0289 (18)0.055 (2)0.0028 (17)0.037 (2)0.0019 (16)
O20.058 (2)0.0271 (18)0.051 (2)0.0039 (15)0.0227 (18)0.0000 (16)
O30.040 (2)0.047 (2)0.0457 (19)0.0031 (15)0.0176 (16)0.0053 (16)
O40.036 (2)0.064 (3)0.050 (2)0.0026 (17)0.0219 (17)0.0016 (18)
Zn10.0426 (4)0.0295 (3)0.0410 (3)0.0012 (2)0.0210 (2)0.0022 (3)
Geometric parameters (Å, º) top
C1—O11.258 (6)C7—C81.512 (8)
C1—O21.271 (6)C7—H7A0.970
C1—C21.498 (6)C7—H7B0.970
C2—C31.523 (7)C8—C91.496 (9)
C2—H2A0.970C8—H8A0.970
C2—H2B0.970C8—H8B0.970
C3—C41.506 (7)C9—C101.515 (10)
C3—H3A0.970C9—H9A0.970
C3—H3B0.970C9—H9B0.970
C4—C51.525 (8)C10—H10A0.960
C4—H4A0.970C10—H10B0.960
C4—H4B0.970C10—H10C0.960
C5—H5A0.960Zn1—O11.950 (3)
C5—H5B0.960O2—Zn1i1.947 (3)
C5—H5C0.960Zn1—O31.966 (3)
C6—O41.256 (6)O4—Zn1ii1.963 (4)
C6—O31.263 (6)Zn1—O2iii1.947 (3)
C6—C71.491 (7)Zn1—O4iv1.963 (4)
O1—C1—O2120.5 (4)C8—C7—H7A108.2
O1—C1—C2121.2 (4)C6—C7—H7B108.2
O2—C1—C2118.4 (4)C8—C7—H7B108.2
C1—C2—C3116.5 (4)H7A—C7—H7B107.4
C1—C2—H2A108.2C9—C8—C7114.0 (6)
C3—C2—H2A108.2C9—C8—H8A108.8
C1—C2—H2B108.2C7—C8—H8A108.8
C3—C2—H2B108.2C9—C8—H8B108.8
H2A—C2—H2B107.3C7—C8—H8B108.8
C4—C3—C2112.2 (4)H8A—C8—H8B107.7
C4—C3—H3A109.2C8—C9—C10113.7 (7)
C2—C3—H3A109.2C8—C9—H9A108.8
C4—C3—H3B109.2C10—C9—H9A108.8
C2—C3—H3B109.2C8—C9—H9B108.8
H3A—C3—H3B107.9C10—C9—H9B108.8
C3—C4—C5113.1 (5)H9A—C9—H9B107.7
C3—C4—H4A109.0C9—C10—H10A109.5
C5—C4—H4A109.0C9—C10—H10B109.5
C3—C4—H4B109.0H10A—C10—H10B109.5
C5—C4—H4B109.0C9—C10—H10C109.5
H4A—C4—H4B107.8H10A—C10—H10C109.5
C4—C5—H5A109.5H10B—C10—H10C109.5
C4—C5—H5B109.5C1—O1—Zn1133.1 (3)
H5A—C5—H5B109.5C1—O2—Zn1i117.8 (3)
C4—C5—H5C109.5C6—O3—Zn1128.3 (3)
H5A—C5—H5C109.5C6—O4—Zn1ii115.0 (3)
H5B—C5—H5C109.5O2iii—Zn1—O1107.80 (15)
O4—C6—O3120.7 (5)O2iii—Zn1—O4iv112.66 (15)
O4—C6—C7119.0 (5)O1—Zn1—O4iv116.62 (17)
O3—C6—C7120.3 (4)O2iii—Zn1—O3113.19 (15)
C6—C7—C8116.2 (5)O1—Zn1—O3100.89 (15)
C6—C7—H7A108.2O4iv—Zn1—O3105.21 (14)
Symmetry codes: (i) x, y1, z; (ii) x1/2, y+1/2, z; (iii) x, y+1, z; (iv) x+1/2, y+1/2, z.

Experimental details

Crystal data
Chemical formula[Zn(C5H9O2)2]
Mr267.63
Crystal system, space groupMonoclinic, P21/a
Temperature (K)293
a, b, c (Å)9.389 (2), 4.782 (1), 29.126 (7)
β (°) 104.256 (7)
V3)1267.5 (5)
Z4
Radiation typeMo Kα
µ (mm1)1.93
Crystal size (mm)0.30 × 0.30 × 0.05
Data collection
DiffractometerRigaku R-AXIS IIC image-plate
diffractometer
Absorption correctionMulti-scan
(CrystalClear; Rigaku, 2000)
Tmin, Tmax0.621, 1.000
No. of measured, independent and
observed [I > 2σ(I)] reflections
7493, 2125, 1965
Rint0.062
(sin θ/λ)max1)0.594
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.062, 0.126, 1.17
No. of reflections2125
No. of parameters138
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.32, 0.52

Computer programs: CrystalClear (Rigaku, 2000), SIR92 (Altomare et al., 1994), SHELXL97 (Sheldrick, 2008), Mercury (Macrae et al., 2006) and DIAMOND (Bergerhoff et al., 1996).

Selected geometric parameters (Å, º) top
Zn1—O11.950 (3)Zn1—O2i1.947 (3)
Zn1—O31.966 (3)Zn1—O4ii1.963 (4)
O2i—Zn1—O1107.80 (15)O2i—Zn1—O3113.19 (15)
O2i—Zn1—O4ii112.66 (15)O1—Zn1—O3100.89 (15)
O1—Zn1—O4ii116.62 (17)O4ii—Zn1—O3105.21 (14)
Symmetry codes: (i) x, y+1, z; (ii) x+1/2, y+1/2, z.
 

Acknowledgements

The authors express thanks to Ms Susanne Olsson of the X-ray Crystallography Laboratory in the Department of Chemistry of the University of Gothenberg, Sweden, for her assistance with aspects of the single-crystal work.

References

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