Di-μ-acetato-κ3 O,O′:O;κ3 O:O,O′-bis­[(acetato-κ2 O,O′)(1,10-phenan­throline-κ2 N,N′)cadmium(II)]

Miguel Angel Harvey; Sergio Baggio; María Teresa Garland; Ricardo Baggio

doi:10.1107/S1600536808029462

. 2008 Oct 22;64(Pt 11):m1450. doi: 10.1107/S1600536808029462

Di-μ-acetato-κ³ O,O′:O;κ³ O:O,O′-bis[(acetato-κ² O,O′)(1,10-phenanthroline-κ² N,N′)cadmium(II)]

Miguel Angel Harvey ^a,^b,^*, Sergio Baggio ^b,^c, María Teresa Garland ^d, Ricardo Baggio ^e

PMCID: PMC2959765 PMID: 21580889

Abstract

The title compound, [Cd₂(C₂H₃O₂)₄(C₁₂H₈N₂)₂], consists of dimeric units built up around a crystallographic symmetry centre. Each cadmium(II) unit is chelated by a 1,10-phenanthroline (phen) group and two acetate ligands, one of which also acts as a bridge, linking both seven-coordinated cadmium(II) centres. The crystal structure is governed by a single π–π interaction between stacked phen groups [centroid–centroid distance 3.5209 (11) Å], leading to a planar structure parallel to (010).

Related literature

For related literature, see: Brown & Altermatt (1985 ▶); Janiak (2000 ▶); Harvey et al. (2006 ▶).

Experimental

Crystal data

[Cd₂(C₂H₃O₂)₄(C₁₂H₈N₂)₂]
M _r = 821.40
Orthorhombic,
a = 8.4422 (7) Å
b = 15.6384 (13) Å
c = 22.2195 (18) Å
V = 2933.5 (4) Å³
Z = 4
Mo Kα radiation
μ = 1.51 mm⁻¹
T = 150 (2) K
0.50 × 0.40 × 0.20 mm

Data collection

Bruker SMART CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2001 ▶) T _min = 0.50, T _max = 0.74
22676 measured reflections
3331 independent reflections
3062 reflections with I > 2σ(I)
R _int = 0.020

Refinement

R[F ² > 2σ(F ²)] = 0.024
wR(F ²) = 0.064
S = 1.06
3331 reflections
210 parameters
H-atom parameters constrained
Δρ_max = 1.58 e Å⁻³
Δρ_min = −0.40 e Å⁻³

Data collection: SMART (Bruker, 2001 ▶); cell refinement: SAINT (Bruker, 2001 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL and PLATON (Spek, 2003 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808029462/kj2097sup1.cif

e-64-m1450-sup1.cif^{(17.9KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808029462/kj2097Isup2.hkl

e-64-m1450-Isup2.hkl^{(163.5KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Selected bond lengths (Å).

Cd1—O13	2.2594 (15)
Cd1—O14	2.3239 (13)
Cd1—N1	2.3466 (15)
Cd1—N2	2.3890 (18)
Cd1—O14ⁱ	2.4398 (13)
Cd1—O24	2.4561 (15)
Cd1—O23	2.5425 (16)

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Symmetry code: (i) Inline graphic .

Acknowledgments

We acknowledge the Spanish Research Council (CSIC) for providing us with a free-of-charge licence for the CSD (Allen, 2002 ▶).

supplementary crystallographic information

Comment

The title compound consists of dimeric units located around a crystallographic symmetry centre (Fig. 1) and made up of two Cd cations, two 1,10-phenanthroline (phen) molecules and four acetate anions. Each cadmium(II) unit is chelated by a phen group (through both nitrogen atoms), and two acetates (through their carboxylato oxygens). A seventh coordination bond adds to these three chelating bites, by way of one of the latter oxygens which acts also as a bridge linking both cadmium(II) centres (Fig. 1). Table 1 presents the coordination distances achieved. The Cd-Cd distance (Cd1···Cd1ⁱ: 3.846 (1)Å, (i): 2-x, 1-y, 1-z) as well as the O-Cd-O angle (O14-Cd1-O14ⁱ: 72.37 (5) °) are unexceptional.

This coordination scheme of the bis(µ₂-acetato)-bis(acetato)-bis(L) type (L: a chelating aromatic amine) leading to a dimeric unit is not common among transition metal cations and in fact this is the first case reported.

The description of coordination geometries when chelating ligands are involved usually poses intrinsic difficulties which can be elegantly surmounted through a vectorial description of the ligand geometry, as proposed by Harvey et al. (2006) based on the Bond Valence Theory (Brown and Altermatt, 1985). When applied to the present case, the geometrical outcome turns out to be a tetrahedron, with angles between ligand vectors spanning the range 91.3 (1)–124.6 (1)°. The fact that the two main values associated with the theory, i.e. the bond valence sum (2.01 valence units, (v.u).) and the modulus of the bond valence vector (0.06 v.u.), agree almost perfectly with expected values (2.00 v.u. and 0.00 v.u., respectively) suggests a significant stability of this coordination sphere.

Regarding non-covalent interactions, there are just a few and not too strong either. The only hydrogen bond present (Table 2) is a non conventional, intramolecular one linking one of the methyl hydrogens to a carboxylato oxygen (Fig. 1). In fact the packing is governed by a single π···π interaction (Table 3 and Fig. 2) between staked phen groups, which gives raise to weakly interacting planar structures paralell to (010).

Experimental

The title compound was obtained by direct mixing of two 0.15 M solutions of cadmium acetate dihydrate and 1,10-phenanthroline in dimethylformamide. Colorless needles began to develop at once, and after one day adequate crystals for X-ray diffraction could be extracted.