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The title compound, [Zn2(C6H5)2(C6H5O)2(C4H10O)2], was isolated from a solution of diphenyl­zinc in diethyl ether that had been exposed to air. The mol­ecules are dinuclear, with a distorted tetra­hedral coordination geometry around the Zn atoms and with mol­ecules situated about a crystallographic inversion centre. Mol­ecules associate via three sets of C—H...π(arene) inter­actions, leading to a network structure.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270107057514/gg3123sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270107057514/gg3123Isup2.hkl
Contains datablock I

CCDC reference: 677076

Comment top

Organozinc reagents are known to be highly sensitive towards atmospheric O2, as noted by Edward Frankland during his pioneering work on organozinc compounds (see, for example, Frankland, 1852, 1855; Seyferth, 2001). This forced Frankland to develop several ingenious apparatus in order to synthesize, purify and analyse the highly reactive compounds he had discovered (Frankland, 1855). Low molecular weight dialkylzinc compounds (ZnMe2, ZnEt2 and ZnPr2) ignite spontaneously when exposed to air (Boersma, 1982a). Slow oxidation of organozinc reagents by low concentrations of O2 is known to give rise to the corresponding alkoxides, with zinc organoperoxides as intermediates (Boersma, 1982b). The formation of alkoxides by the action of O2 on dialkylzinc compounds was first reported in the case of diethylzinc by Frankland (1855), who identified zinc ethoxide as one of the products obtained in the reaction of diethyl zinc and oxygen.

The title compound, (I), was isolated from a diethyl ether solution of diphenylzinc (standing in a Schlenk tube) after a long time period (3.5 years), where the solution had partially attacked the silicon grease on the stopcock, causing a minute leak of atmospheric O2 into the tube. Compound (I) is a dinuclear zinc complex, situated about a crystallographic inversion centre (Fig. 1). The coordination geometry around Zn1 is highly distorted tetrahedral with a Zn1—C1 distance of 1.964 (2) Å, Zn—O bond lengths of 1.9898 (14), 2.0008 (14) and 2.0939 (15) Å, and angles about the Zn centre ranging from 79.31 (6)° to 130.39 (7)°. The coordination of diethylether to zinc is, perhaps surprisingly, rare among the structures in the Cambridge Structural Database (CSD; Version 5.28 of November 2006; Allen 2002). Only 11 structures were found containing a Zn–OEt2 fragment. Among these, two examples of organozinc complexes, bis[(µ2-chloro)(1,1-dichloro-2,2,2-trifluoromethyl)(diethyl ether)zinc(II)] (Behm et al., 1993) and tris(diethyl ether)(ethyl)zinc(II) tetrakis(pentafluorophenyl)borate (Walker et al., 2001), as well as one example of a zinc aryloxide, bis[(diethyl ether)(2,6-diphenylphenoxy)]zinc(II) (Darensbourg et al., 1999), are to be found.

Several crystal structures for zinc aryloxides and organozinc aryloxides have been published and are reported in the CSD, but none of the structures are closely related to (I). A total of 146 structures are found where two Zn atoms are bridged by two aryloxide groups. Most of these structures include complex aryloxide groups, having for example N-donor substituents coordinating to Zn, e.g. bis{[µ2-2-(diethylaminomethyl)phenoxo](ethyl)zinc(II)} (Hunger et al., 2005). Structures having a monodentate neutral ligand at Zn, as for (I), are rare. There is only one example of an organozinc aryloxide bearing a coordinating ligand at Zn, viz. bis[(µ2-2,6-dimethylphenoxo)(ethyl)(pyridyl)zinc(II)] (Boyle et al., 2004). Two structures of bridged zinc aryloxides having monodentate neutral ligands at Zn are reported in the CSD, viz. bis[(µ2-2,6-difluorophenoxo)(2,6-difluorophenoxo)(tetrahydrofuran)zinc(II)] and bis[(µ2-2,6-difluorophenoxo)(2,6-difluorophenoxo)(tricyclohexylphosphine)zinc(II)] tetrahydrofuran solvate (Darensbourg et al., 2000). Another structure somewhat similar to (I) is bis[(µ2-2,3-dihydro-2,2-dimethylbenzofuranoxide)(chloro)(pyridine)zinc(II)] (Sobota et al., 2000). In addition, there are a number of complexes with three-coordinate Zn atoms. In this category, there is one example of a base-free zinc aryloxide, viz. bis[(µ2-2,6-di-t-butylphenoxo)(2,6-di-t-butylphenoxo)zinc(II)] n-pentane solvate (Kunert et al., 2000). Other examples include bis[(µ2-2,6-di-t-butylphenoxo)(ethyl)zinc(II)] (Parvez et al., 1992) and [(µ2-2,6-di-isopropylphenoxo)(trimethylsilylmethyl)zinc(II)] (Olmstead et al., 1991). There are no structures of Zn(OPh)2 complexes in the CSD, but there are eight structures of derivatives bearing one phenoxo ligand at zinc, e.g. bis(µ2-phenoxo)[N-isopropyl-2-(isopropylamino)troponiminato]zinc(II) (Herrmann et al., 2004) and bis(µ3-phenoxo)tetrakis(µ2-2,2-dimethyl-3,5-hexanedionato)(diphenyl)tetrazinc(II) (Boersma et al., 1974). The latter example is the only structure in the CSD of a phenylzinc–phenoxide complex (Fig. 2). The Zn···Zn distances in this structure are 3.177, 3.239 and 3.171 Å, slightly longer than that in (I) [3.0724 (6) Å].

The crystal structure of (I) displays three sets of C—H···π interactions (Nishio, 2004; Cantrill et al., 2000; Braga et al., 1998; Viswamitra et al., 1993). The shortest set of C—H···π interactions involves atom H14A and the (C1–C6)ii phenyl ring [symmetry code: (ii) x + 1, y, z] and gives rise to chains extending along the a axis. The second shortest set of C—H···π contacts involves atom H10 and the (C1–C6)i phenyl ring [symmetry code: (i) -x + 1/2, y - 1/2, -z + 1/2]. These interactions result in layers extending parallel to the (202) set of planes. A third set of interactions can be identified, viz. atom H15A interacts with the (C1–C6)iii phenyl ring [symmetry code: (iii) x + 1/2, -y + 3/2, z + 1/2]. These interactions give rise to layers parallel to (202). The three sets of interactions result in a network structure, and these interactions are depicted in Fig. 3.

Zinc aryloxides have found use in carbon dioxide activation and may have future potential as an activator of this greenhouse gas. Darensbourg and co-workers reported that zinc aryloxides catalyse the copolymerization of carbon dioxide and epoxides (Darensbourg & Holtcamp, 1995; Darensbourg et al., 1999). Fixation of carbon dioxide by carboxylation of acetophenone using zinc aryloxide catalysts has also been reported (Kunert et al., 2000).

Related literature top

For related literature, see: Allen (2002); Behm et al. (1993); Boersma (1982a, 1982b); Boersma et al. (1974); Boyle et al. (2004); Braga et al. (1998); Cantrill et al. (2000); Darensbourg & Holtcamp (1995); Darensbourg et al. (1999); Frankland (1852, 1855); Hunger et al. (2005); Kunert et al. (2000); Nishio (2004); Olmstead et al. (1991); Parvez et al. (1992); Seyferth (2001); Sobota et al. (2000); Viswamitra et al. (1993); Walker et al. (2001).

Experimental top

Bromobenzene (4.1 ml, 0.039 mol) was added to a stirred mixture of Mg (1.1 g, 0.045 mol) and diethyl ether (40 ml). The mixture was stirred overnight at ambient temperature. The solution was added dropwise to a suspension of ZnCl2 (2.6 g, 0.019 mol) in diethyl ether (10 ml) at 273 K. The reaction mixture was stirred at ambient temperature overnight, evaporated and sublimated at 10-2 mbar. The white product was dissolved in diethyl ether (4 ml). After 3.5 years of storage at 238 K, the silicon grease had been heavily attacked by the ZnPh2 solution, resulting in leakage of atmospheric O2 into the Schlenk tube. Large colourless hexagonal–prismatic crystals of (I) were isolated.

Refinement top

All H atoms were included in calculated positions (C—H = 0.93–0.97 Å) and refined using a riding model with Uiso(H) values of 1.2 or 1.5 times Ueq(C).

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., 1993); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997) and PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).

Figures top
[Figure 1]
[Figure 2]
Figure 1. A view of (I), with the atomic numbering scheme; atoms with the suffix 'A' indicate symmetry-related equivalents. Displacement ellipsoids are drawn at the 30% probability level and H atoms are included with radii of an arbitrary size.

Figure 2. A schematic drawing of the phenylzinc phenoxide derivative bis(µ3-phenoxo)tetrakis(µ2-2,2-dimethyl-3,5-ηexanedionato-)(diphenyl)tetrazinc(II) (Boersma et al., 1974).

Figure 3. The structure of (I) has three sets of C—H···π(arene) interactions. The unit cell of (I) when viewed along the b axis (left, with H14A interaction) and along the c axis (right, with the H10 and H15A interactions).
(I) top
Crystal data top
[Zn2(C6H5)2(C6H5O)2(C4H10O)2]F(000) = 648
Mr = 619.42Dx = 1.356 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 2729 reflections
a = 8.5115 (13) Åθ = 3.1–25.5°
b = 12.8018 (18) ŵ = 1.61 mm1
c = 14.128 (2) ÅT = 100 K
β = 99.814 (5)°Prism, colourless
V = 1516.9 (4) Å30.30 × 0.25 × 0.15 mm
Z = 2
Data collection top
Rigaku R-AXIS IIC image-plate system
diffractometer
2729 independent reflections
Radiation source: rotating-anode X-ray tube, Rigaku RU-H3R2540 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.030
Detector resolution: 105 pixels mm-1θmax = 25.5°, θmin = 3.1°
ϕ scansh = 910
Absorption correction: multi-scan
(CrystalClear; Rigaku, 2000)
k = 1515
Tmin = 0.559, Tmax = 0.785l = 1717
9541 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)] = 0.031Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.080H-atom parameters constrained
S = 1.08 w = 1/[σ2(Fo2) + (0.0418P)2 + 1.443P]
where P = (Fo2 + 2Fc2)/3
2729 reflections(Δ/σ)max < 0.001
172 parametersΔρmax = 0.88 e Å3
0 restraintsΔρmin = 0.39 e Å3
Crystal data top
[Zn2(C6H5)2(C6H5O)2(C4H10O)2]V = 1516.9 (4) Å3
Mr = 619.42Z = 2
Monoclinic, P21/nMo Kα radiation
a = 8.5115 (13) ŵ = 1.61 mm1
b = 12.8018 (18) ÅT = 100 K
c = 14.128 (2) Å0.30 × 0.25 × 0.15 mm
β = 99.814 (5)°
Data collection top
Rigaku R-AXIS IIC image-plate system
diffractometer
2729 independent reflections
Absorption correction: multi-scan
(CrystalClear; Rigaku, 2000)
2540 reflections with I > 2σ(I)
Tmin = 0.559, Tmax = 0.785Rint = 0.030
9541 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0310 restraints
wR(F2) = 0.080H-atom parameters constrained
S = 1.08Δρmax = 0.88 e Å3
2729 reflectionsΔρmin = 0.39 e Å3
172 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
C10.3576 (2)0.74388 (16)0.02054 (14)0.0160 (4)
C20.1911 (3)0.74190 (17)0.02415 (15)0.0202 (4)
H20.14310.67990.00990.024*
C30.0966 (3)0.82957 (18)0.04825 (16)0.0234 (5)
H30.01300.82540.05000.028*
C40.1645 (3)0.92329 (18)0.06971 (16)0.0230 (5)
H40.10130.98210.08530.028*
C50.3284 (3)0.92804 (16)0.06767 (15)0.0199 (4)
H50.37540.99010.08260.024*
C60.4220 (2)0.83953 (16)0.04323 (14)0.0170 (4)
H60.53140.84420.04190.020*
C70.3473 (2)0.45984 (16)0.14165 (14)0.0146 (4)
C80.2816 (3)0.36151 (18)0.15141 (18)0.0247 (5)
H80.28410.31110.10430.030*
C90.2122 (3)0.3385 (2)0.2314 (2)0.0342 (6)
H90.16830.27280.23710.041*
C100.2080 (3)0.4126 (2)0.30256 (17)0.0317 (6)
H100.16330.39660.35650.038*
C110.2711 (3)0.5101 (2)0.29210 (17)0.0333 (6)
H110.26650.56080.33870.040*
C120.3415 (3)0.5337 (2)0.21285 (17)0.0285 (5)
H120.38500.59970.20750.034*
C130.7892 (3)0.5633 (2)0.16054 (18)0.0317 (5)
H13A0.73080.49790.15640.038*
H13B0.83210.57620.22760.038*
C140.9211 (3)0.5552 (3)0.1052 (2)0.0431 (7)
H14A0.99080.49920.13040.065*
H14B0.97970.61960.11020.065*
H14C0.87840.54170.03900.065*
C150.6905 (3)0.7359 (2)0.18669 (17)0.0305 (5)
H15A0.69130.71140.25170.037*
H15B0.59550.77810.16830.037*
C160.8334 (4)0.8025 (2)0.1854 (3)0.0472 (7)
H16A0.83200.86020.22870.071*
H16B0.83230.82860.12150.071*
H16C0.92810.76190.20510.071*
O10.41506 (17)0.48186 (11)0.06415 (10)0.0167 (3)
O20.68260 (19)0.64720 (13)0.12344 (12)0.0269 (4)
Zn10.48567 (3)0.618065 (17)0.016024 (16)0.01466 (11)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0211 (10)0.0147 (9)0.0119 (9)0.0009 (8)0.0019 (7)0.0005 (7)
C20.0237 (11)0.0169 (10)0.0208 (10)0.0041 (8)0.0058 (8)0.0011 (8)
C30.0194 (10)0.0264 (12)0.0235 (11)0.0011 (9)0.0012 (8)0.0012 (9)
C40.0272 (11)0.0190 (11)0.0204 (10)0.0065 (9)0.0027 (9)0.0007 (9)
C50.0293 (11)0.0136 (10)0.0156 (10)0.0037 (8)0.0008 (8)0.0009 (8)
C60.0195 (10)0.0162 (10)0.0151 (9)0.0017 (8)0.0025 (8)0.0023 (8)
C70.0120 (9)0.0180 (10)0.0130 (9)0.0009 (7)0.0002 (7)0.0031 (8)
C80.0292 (12)0.0167 (10)0.0313 (12)0.0006 (9)0.0136 (10)0.0014 (9)
C90.0410 (14)0.0239 (12)0.0426 (15)0.0006 (11)0.0217 (12)0.0120 (11)
C100.0262 (12)0.0511 (16)0.0188 (11)0.0012 (11)0.0069 (9)0.0108 (11)
C110.0323 (13)0.0509 (17)0.0181 (11)0.0165 (11)0.0081 (10)0.0141 (11)
C120.0337 (12)0.0283 (12)0.0259 (12)0.0165 (10)0.0122 (10)0.0085 (10)
C130.0345 (13)0.0266 (12)0.0315 (13)0.0047 (10)0.0015 (10)0.0036 (10)
C140.0426 (16)0.0519 (18)0.0319 (14)0.0050 (13)0.0018 (12)0.0006 (13)
C150.0368 (13)0.0306 (13)0.0222 (12)0.0023 (10)0.0006 (10)0.0055 (10)
C160.0458 (16)0.0309 (14)0.0620 (19)0.0107 (12)0.0007 (14)0.0170 (14)
O10.0227 (7)0.0126 (6)0.0164 (7)0.0018 (6)0.0076 (6)0.0006 (6)
O20.0283 (8)0.0166 (7)0.0304 (9)0.0028 (7)0.0105 (7)0.0052 (7)
Zn10.01876 (16)0.01023 (15)0.01496 (16)0.00033 (8)0.00281 (10)0.00062 (8)
Geometric parameters (Å, º) top
C1—C61.401 (3)C11—C121.390 (3)
C1—C21.410 (3)C11—H110.9300
C1—Zn11.964 (2)C12—H120.9300
C2—C31.389 (3)C13—O21.446 (3)
C2—H20.9300C13—C141.477 (4)
C3—C41.387 (3)C13—H13A0.9700
C3—H30.9300C13—H13B0.9700
C4—C51.392 (3)C14—H14A0.9600
C4—H40.9300C14—H14B0.9600
C5—C61.394 (3)C14—H14C0.9600
C5—H50.9300C15—O21.440 (3)
C6—H60.9300C15—C161.488 (4)
C7—O11.351 (2)C15—H15A0.9700
C7—C121.388 (3)C15—H15B0.9700
C7—C81.394 (3)C16—H16A0.9600
C8—C91.393 (3)C16—H16B0.9600
C8—H80.9300C16—H16C0.9600
C9—C101.387 (4)O1—Zn1i1.9898 (14)
C9—H90.9300O1—Zn12.0008 (14)
C10—C111.377 (4)O2—Zn12.0939 (15)
C10—H100.9300Zn1—Zn1i3.0724 (6)
C6—C1—C2115.94 (19)C14—C13—H13A109.6
C6—C1—Zn1123.78 (15)O2—C13—H13B109.6
C2—C1—Zn1120.28 (15)C14—C13—H13B109.6
C3—C2—C1122.1 (2)H13A—C13—H13B108.1
C3—C2—H2119.0C13—C14—H14A109.5
C1—C2—H2119.0C13—C14—H14B109.5
C4—C3—C2120.4 (2)H14A—C14—H14B109.5
C4—C3—H3119.8C13—C14—H14C109.5
C2—C3—H3119.8H14A—C14—H14C109.5
C3—C4—C5119.1 (2)H14B—C14—H14C109.5
C3—C4—H4120.4O2—C15—C16113.3 (2)
C5—C4—H4120.4O2—C15—H15A108.9
C4—C5—C6119.9 (2)C16—C15—H15A108.9
C4—C5—H5120.1O2—C15—H15B108.9
C6—C5—H5120.1C16—C15—H15B108.9
C5—C6—C1122.53 (19)H15A—C15—H15B107.7
C5—C6—H6118.7C15—C16—H16A109.5
C1—C6—H6118.7C15—C16—H16B109.5
O1—C7—C12121.21 (19)H16A—C16—H16B109.5
O1—C7—C8120.15 (19)C15—C16—H16C109.5
C12—C7—C8118.6 (2)H16A—C16—H16C109.5
C9—C8—C7120.3 (2)H16B—C16—H16C109.5
C9—C8—H8119.9C7—O1—Zn1i127.47 (13)
C7—C8—H8119.9C7—O1—Zn1130.65 (13)
C10—C9—C8120.7 (2)Zn1i—O1—Zn1100.69 (6)
C10—C9—H9119.7C15—O2—C13113.66 (18)
C8—C9—H9119.7C15—O2—Zn1122.50 (14)
C11—C10—C9118.9 (2)C13—O2—Zn1120.38 (14)
C11—C10—H10120.6C1—Zn1—O1i130.39 (7)
C9—C10—H10120.6C1—Zn1—O1128.23 (7)
C10—C11—C12120.9 (2)O1i—Zn1—O179.31 (6)
C10—C11—H11119.6C1—Zn1—O2112.60 (7)
C12—C11—H11119.6O1i—Zn1—O299.32 (6)
C7—C12—C11120.6 (2)O1—Zn1—O299.13 (6)
C7—C12—H12119.7C1—Zn1—Zn1i145.34 (6)
C11—C12—H12119.7O1i—Zn1—Zn1i39.78 (4)
O2—C13—C14110.3 (2)O1—Zn1—Zn1i39.52 (4)
O2—C13—H13A109.6O2—Zn1—Zn1i102.02 (4)
Symmetry code: (i) x+1, y+1, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C10—H10···Cg1ii0.932.763.542 (3)143
C14—H14a···Cg2iii0.962.683.539 (3)149
C15—H15a···Cg2iv0.972.883.834 (3)167
Symmetry codes: (ii) x+1/2, y1/2, z+1/2; (iii) x+1, y, z; (iv) x+1/2, y+3/2, z+1/2.

Experimental details

Crystal data
Chemical formula[Zn2(C6H5)2(C6H5O)2(C4H10O)2]
Mr619.42
Crystal system, space groupMonoclinic, P21/n
Temperature (K)100
a, b, c (Å)8.5115 (13), 12.8018 (18), 14.128 (2)
β (°) 99.814 (5)
V3)1516.9 (4)
Z2
Radiation typeMo Kα
µ (mm1)1.61
Crystal size (mm)0.30 × 0.25 × 0.15
Data collection
DiffractometerRigaku R-AXIS IIC image-plate system
diffractometer
Absorption correctionMulti-scan
(CrystalClear; Rigaku, 2000)
Tmin, Tmax0.559, 0.785
No. of measured, independent and
observed [I > 2σ(I)] reflections
9541, 2729, 2540
Rint0.030
(sin θ/λ)max1)0.606
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.031, 0.080, 1.08
No. of reflections2729
No. of parameters172
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.88, 0.39

Computer programs: CrystalClear (Rigaku, 2000), SIR92 (Altomare et al., 1993), SHELXL97 (Sheldrick, 1997), ORTEP-3 (Farrugia, 1997) and PLATON (Spek, 2003).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C10—H10···Cg1i0.9302.7583.542 (3)143
C14—H14a···Cg2ii0.9602.6813.539 (3)149
C15—H15a···Cg2iii0.9702.8843.834 (3)167
Symmetry codes: (i) x+1/2, y1/2, z+1/2; (ii) x+1, y, z; (iii) x+1/2, y+3/2, z+1/2.
 

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