Anhydrous polymeric zinc(II) penta­noate

Taylor, R.A.; Ellis, H.A.

doi:10.1107/S1600536808008283

metal-organic compounds

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Volume 64| Part 7| July 2008| Page m895

doi:10.1107/S1600536808008283

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Anhydrous polymeric zinc(II) pentanoate

Richard A. Taylor ^a and Henry A. Ellis ^a ^*

^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 syn–anti 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 ); 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

Crystal data

[Zn(C₅H₉O₂)₂]
M_r = 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 ) T_min = 0.621, T_max = 1.000 (expected range = 0.564–0.908)
7493 measured reflections
2125 independent reflections
1965 reflections with I > 2σ(I)
R_int = 0.061

Refinement

R[F² > 2σ(F²)] = 0.062
wR(F²) = 0.126
S = 1.17
2125 reflections
138 parameters
H-atom parameters constrained
Δρ_max = 0.32 e Å⁻³
Δρ_min = −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); cell refinement: CrystalClear; data reduction: CrystalClear; 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.

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808008283/cf2188sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808008283/cf2188Isup2.hkl

checkCIF report

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.

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

	Fig. 1. : Asymmetric unit of zinc(II) n-pentanoate: Displacement ellipsoids are drawn at the 75% probability level.
	Fig. 2. : Projection down the b axis. Displacement ellipsoids are drawn at the 50% probability level.
	Fig. 3. : View down the a axis (hydrogen atoms omitted). Displacement ellipsoids are drawn at the 50% probability level.
	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]	D_x = 1.402 Mg m⁻³
M_r = 267.63	Melting point: 425.5 K
Monoclinic, P2₁/a	Mo Kα radiation, λ = 0.71073 Å
a = 9.389 (2) Å	Cell parameters from 7493 reflections
b = 4.782 (1) Å	θ = 2.2–25.0°
c = 29.126 (7) Å	µ = 1.93 mm⁻¹
β = 104.256 (7)°	T = 293 K
V = 1267.5 (5) Å³	Thin block, colourless
Z = 4	0.30 × 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 tube	1965 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.062
Detector resolution: 105 pixels mm^-1	θ_max = 25.0°, θ_min = 2.2°
ϕ scans	h = −11→11
Absorption correction: multi-scan (CrystalClear; Rigaku, 2000)	k = −5→5
T_min = 0.621, T_max = 1.000	l = −34→34
7493 measured reflections

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)] = 0.062	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.126	H-atom parameters constrained
S = 1.17	w = 1/[σ²(F_o²) + (0.0408P)² + 3.0707P] where P = (F_o² + 2F_c²)/3
2125 reflections	(Δ/σ)_max < 0.001
138 parameters	Δρ_max = 0.32 e Å⁻³
0 restraints	Δρ_min = −0.52 e Å⁻³

Crystal data top

[Zn(C₅H₉O₂)₂]	V = 1267.5 (5) Å³
M_r = 267.63	Z = 4
Monoclinic, P2₁/a	Mo Kα radiation
a = 9.389 (2) Å	µ = 1.93 mm⁻¹
b = 4.782 (1) Å	T = 293 K
c = 29.126 (7) Å	0.30 × 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)
T_min = 0.621, T_max = 1.000	R_int = 0.062
7493 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.062	0 restraints
wR(F²) = 0.126	H-atom parameters constrained
S = 1.17	Δρ_max = 0.32 e Å⁻³
2125 reflections	Δρ_min = −0.52 e Å⁻³
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

	x	y	z	U_iso*/U_eq
C1	0.7184 (5)	−0.3109 (10)	0.19302 (17)	0.0350 (10)
C2	0.7780 (6)	−0.1602 (11)	0.15666 (19)	0.0456 (13)
H2A	0.8636	−0.0544	0.1731	0.055*
H2B	0.7047	−0.0267	0.1407	0.055*
C3	0.8215 (6)	−0.3404 (11)	0.11919 (19)	0.0462 (13)
H3A	0.8985	−0.4689	0.1346	0.055*
H3B	0.7374	−0.4503	0.1029	0.055*
C4	0.8750 (7)	−0.1677 (13)	0.0835 (2)	0.0571 (15)
H4A	0.9595	−0.0591	0.1000	0.069*
H4B	0.7983	−0.0376	0.0686	0.069*
C5	0.9177 (9)	−0.3437 (17)	0.0453 (2)	0.081 (2)
H5A	0.9946	−0.4712	0.0599	0.122*
H5B	0.9517	−0.2233	0.0239	0.122*
H5C	0.8338	−0.4473	0.0282	0.122*
C6	0.4620 (5)	0.1354 (11)	0.29619 (18)	0.0405 (12)
C7	0.5718 (6)	−0.0210 (14)	0.3329 (2)	0.0569 (16)
H7A	0.6541	0.1024	0.3456	0.068*
H7B	0.6085	−0.1756	0.3176	0.068*
C8	0.5177 (7)	−0.1364 (17)	0.3739 (2)	0.0666 (18)
H8A	0.4695	0.0125	0.3870	0.080*
H8B	0.4450	−0.2800	0.3621	0.080*
C9	0.6363 (9)	−0.258 (2)	0.4128 (3)	0.097 (3)
H9A	0.7112	−0.1168	0.4237	0.116*
H9B	0.6817	−0.4123	0.4001	0.116*
C10	0.5825 (11)	−0.362 (3)	0.4546 (3)	0.139 (4)
H10A	0.5363	−0.2109	0.4672	0.208*
H10B	0.6642	−0.4303	0.4787	0.208*
H10C	0.5128	−0.5099	0.4446	0.208*
O1	0.6932 (4)	−0.1838 (7)	0.22800 (13)	0.0486 (9)
O2	0.6954 (4)	−0.5724 (7)	0.18803 (12)	0.0438 (9)
O3	0.4976 (4)	0.2344 (7)	0.26038 (12)	0.0431 (8)
O4	0.3333 (4)	0.1625 (8)	0.30100 (13)	0.0480 (9)
Zn1	0.68833 (6)	0.21140 (11)	0.24407 (2)	0.0358 (2)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.040 (3)	0.031 (3)	0.038 (3)	0.000 (2)	0.017 (2)	0.001 (2)
C2	0.065 (4)	0.032 (3)	0.049 (3)	−0.004 (2)	0.032 (3)	0.000 (2)
C3	0.061 (4)	0.035 (3)	0.049 (3)	0.001 (2)	0.027 (3)	−0.006 (2)
C4	0.071 (4)	0.058 (4)	0.050 (3)	0.000 (3)	0.031 (3)	0.001 (3)
C5	0.110 (6)	0.092 (6)	0.059 (4)	−0.004 (5)	0.052 (4)	−0.008 (4)
C6	0.038 (3)	0.037 (3)	0.051 (3)	−0.001 (2)	0.020 (2)	−0.004 (2)
C7	0.045 (3)	0.077 (4)	0.051 (3)	0.011 (3)	0.017 (3)	0.018 (3)
C8	0.051 (4)	0.093 (5)	0.057 (4)	−0.003 (3)	0.017 (3)	0.022 (4)
C9	0.076 (5)	0.144 (9)	0.070 (5)	0.010 (5)	0.015 (4)	0.047 (5)
C10	0.121 (9)	0.214 (13)	0.081 (6)	0.009 (8)	0.025 (6)	0.073 (7)
O1	0.073 (3)	0.0289 (18)	0.055 (2)	−0.0028 (17)	0.037 (2)	−0.0019 (16)
O2	0.058 (2)	0.0271 (18)	0.051 (2)	−0.0039 (15)	0.0227 (18)	0.0000 (16)
O3	0.040 (2)	0.047 (2)	0.0457 (19)	0.0031 (15)	0.0176 (16)	0.0053 (16)
O4	0.036 (2)	0.064 (3)	0.050 (2)	0.0026 (17)	0.0219 (17)	0.0016 (18)
Zn1	0.0426 (4)	0.0295 (3)	0.0410 (3)	−0.0012 (2)	0.0210 (2)	−0.0022 (3)

Geometric parameters (Å, º) top

C1—O1	1.258 (6)	C7—C8	1.512 (8)
C1—O2	1.271 (6)	C7—H7A	0.970
C1—C2	1.498 (6)	C7—H7B	0.970
C2—C3	1.523 (7)	C8—C9	1.496 (9)
C2—H2A	0.970	C8—H8A	0.970
C2—H2B	0.970	C8—H8B	0.970
C3—C4	1.506 (7)	C9—C10	1.515 (10)
C3—H3A	0.970	C9—H9A	0.970
C3—H3B	0.970	C9—H9B	0.970
C4—C5	1.525 (8)	C10—H10A	0.960
C4—H4A	0.970	C10—H10B	0.960
C4—H4B	0.970	C10—H10C	0.960
C5—H5A	0.960	Zn1—O1	1.950 (3)
C5—H5B	0.960	O2—Zn1ⁱ	1.947 (3)
C5—H5C	0.960	Zn1—O3	1.966 (3)
C6—O4	1.256 (6)	O4—Zn1ⁱⁱ	1.963 (4)
C6—O3	1.263 (6)	Zn1—O2ⁱⁱⁱ	1.947 (3)
C6—C7	1.491 (7)	Zn1—O4^iv	1.963 (4)

O1—C1—O2	120.5 (4)	C8—C7—H7A	108.2
O1—C1—C2	121.2 (4)	C6—C7—H7B	108.2
O2—C1—C2	118.4 (4)	C8—C7—H7B	108.2
C1—C2—C3	116.5 (4)	H7A—C7—H7B	107.4
C1—C2—H2A	108.2	C9—C8—C7	114.0 (6)
C3—C2—H2A	108.2	C9—C8—H8A	108.8
C1—C2—H2B	108.2	C7—C8—H8A	108.8
C3—C2—H2B	108.2	C9—C8—H8B	108.8
H2A—C2—H2B	107.3	C7—C8—H8B	108.8
C4—C3—C2	112.2 (4)	H8A—C8—H8B	107.7
C4—C3—H3A	109.2	C8—C9—C10	113.7 (7)
C2—C3—H3A	109.2	C8—C9—H9A	108.8
C4—C3—H3B	109.2	C10—C9—H9A	108.8
C2—C3—H3B	109.2	C8—C9—H9B	108.8
H3A—C3—H3B	107.9	C10—C9—H9B	108.8
C3—C4—C5	113.1 (5)	H9A—C9—H9B	107.7
C3—C4—H4A	109.0	C9—C10—H10A	109.5
C5—C4—H4A	109.0	C9—C10—H10B	109.5
C3—C4—H4B	109.0	H10A—C10—H10B	109.5
C5—C4—H4B	109.0	C9—C10—H10C	109.5
H4A—C4—H4B	107.8	H10A—C10—H10C	109.5
C4—C5—H5A	109.5	H10B—C10—H10C	109.5
C4—C5—H5B	109.5	C1—O1—Zn1	133.1 (3)
H5A—C5—H5B	109.5	C1—O2—Zn1ⁱ	117.8 (3)
C4—C5—H5C	109.5	C6—O3—Zn1	128.3 (3)
H5A—C5—H5C	109.5	C6—O4—Zn1ⁱⁱ	115.0 (3)
H5B—C5—H5C	109.5	O2ⁱⁱⁱ—Zn1—O1	107.80 (15)
O4—C6—O3	120.7 (5)	O2ⁱⁱⁱ—Zn1—O4^iv	112.66 (15)
O4—C6—C7	119.0 (5)	O1—Zn1—O4^iv	116.62 (17)
O3—C6—C7	120.3 (4)	O2ⁱⁱⁱ—Zn1—O3	113.19 (15)
C6—C7—C8	116.2 (5)	O1—Zn1—O3	100.89 (15)
C6—C7—H7A	108.2	O4^iv—Zn1—O3	105.21 (14)

Symmetry codes: (i) x, y−1, z; (ii) x−1/2, −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]
M_r	267.63
Crystal system, space group	Monoclinic, P2₁/a
Temperature (K)	293
a, b, c (Å)	9.389 (2), 4.782 (1), 29.126 (7)
β (°)	104.256 (7)
V (Å³)	1267.5 (5)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	1.93
Crystal size (mm)	0.30 × 0.30 × 0.05

Data collection
Diffractometer	Rigaku R-AXIS IIC image-plate diffractometer
Absorption correction	Multi-scan (CrystalClear; Rigaku, 2000)
T_min, T_max	0.621, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	7493, 2125, 1965
R_int	0.062
(sin θ/λ)_max (Å⁻¹)	0.594

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.062, 0.126, 1.17
No. of reflections	2125
No. of parameters	138
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	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—O1	1.950 (3)	Zn1—O2ⁱ	1.947 (3)
Zn1—O3	1.966 (3)	Zn1—O4ⁱⁱ	1.963 (4)

O2ⁱ—Zn1—O1	107.80 (15)	O2ⁱ—Zn1—O3	113.19 (15)
O2ⁱ—Zn1—O4ⁱⁱ	112.66 (15)	O1—Zn1—O3	100.89 (15)
O1—Zn1—O4ⁱⁱ	116.62 (17)	O4ⁱⁱ—Zn1—O3	105.21 (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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