Bis(acetato-κO)[N,N,N′,N′-tetra­methyl­ethane-1,2-diamine-κ2 N,N′]copper(II)

J Chris Slootweg; Peter Chen

doi:10.1107/S1600536808002584

. 2008 Jan 30;64(Pt 2):m430–m431. doi: 10.1107/S1600536808002584

Bis(acetato-κO)[N,N,N′,N′-tetramethylethane-1,2-diamine-κ² N,N′]copper(II)

J Chris Slootweg ^a,^‡, Peter Chen ^a,^*

PMCID: PMC2960195 PMID: 21201373

Abstract

In the title compound, [Cu(C₂H₃O₂)₂(C₆H₁₆N₂)], the Cu^II atom is coordinated by two N atoms from the chelating N,N,N′,N′-tetramethylethane-1,2-diamine ligand and two O atoms from two acetate anions in a distorted square-planar geometry. In addition, there are longer contacts between Cu and the second O atom of each acetate ligand, which could be considered to complete a distorted octahedral geometry. The molecules in the crystal structure are connected via intermolecular C—H⋯O hydrogen-bonding contacts.

Related literature

For general background, see: Slootweg & Chen (2006 ▶); Gerdes & Chen (2004 ▶); Gerdes (2004 ▶). For related structures, see: Dalai et al. (2002 ▶); Margraf et al. (2005 ▶); Devereux et al. (2007 ▶); Brown et al. (2002 ▶).

Experimental

Crystal data

[Cu(C₂H₃O₂)₂(C₆H₁₆N₂)]
M _r = 297.84
Monoclinic,
a = 8.0201 (5) Å
b = 15.9153 (10) Å
c = 10.8536 (7) Å
β = 90.910 (3)°
V = 1385.20 (15) Å³
Z = 4
Mo Kα radiation
μ = 1.58 mm⁻¹
T = 220 (2) K
0.21 × 0.19 × 0.15 mm

Data collection

Nonius KappaCCD area-detector diffractometer
Absorption correction: none
4704 measured reflections
2711 independent reflections
2321 reflections with I > 2σ(I)
R _int = 0.040

Refinement

R[F ² > 2σ(F ²)] = 0.040
wR(F ²) = 0.106
S = 1.05
2711 reflections
183 parameters
H-atom parameters constrained
Δρ_max = 0.53 e Å⁻³
Δρ_min = −0.45 e Å⁻³

Data collection: COLLECT (Nonius, 2000 ▶); cell refinement: SCALEPACK (Otwinowski & Minor, 1997 ▶); data reduction: DENZO (Otwinowski & Minor, 1997 ▶) and SCALEPACK; program(s) used to solve structure: SIR97 (Altomare et al., 1999 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: PLATON (Spek, 2003 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808002584/si2074sup1.cif

e-64-0m430-sup1.cif^{(18.6KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808002584/si2074Isup2.hkl

e-64-0m430-Isup2.hkl^{(133.1KB, hkl)}

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

Table 1. Selected geometric parameters (Å, °).

Cu1—O14	1.9797 (19)
Cu1—O10	1.9813 (19)
Cu1⋯O12	2.509 (2)
Cu1⋯O16	2.531 (2)
Cu1—N2	2.037 (2)
Cu1—N5	2.047 (2)

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O14—Cu1—O10	92.08 (9)
O14—Cu1—N2	164.30 (9)
O10—Cu1—N2	93.12 (9)
O14—Cu1—N5	92.40 (9)
O10—Cu1—N5	165.18 (9)
N2—Cu1—N5	86.30 (9)

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Table 2. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C3—H3A⋯O12ⁱ	0.98	2.34	3.281 (4)	160
C4—H4A⋯O16ⁱⁱ	0.98	2.50	3.475 (4)	176
C13—H13C⋯O16ⁱⁱⁱ	0.97	2.54	3.507 (4)	173
C17—H17C⋯O12^iv	0.97	2.58	3.542 (4)	170

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) .

Acknowledgments

A TALENT stipend (JCS) of the Netherlands Organization for Scientific Research (NWO) is gratefully acknowledged. We thank Mr P. Seiler for the single-crystal structure determination.

supplementary crystallographic information

Comment

The aspiration of our work is to gain insight into the underlying mechanisms of the catalytic transformations of hydrocarbons by C—H bond activation (Slootweg & Chen, 2006; Gerdes & Chen, 2004) and subsequent oxidative coupling using heterobimetallic catalysis (Gerdes, 2004). Well defined platinum or palladium catalysts are suited for the C—H activation, whearas a copper-catalyzed coupling cycle is ideal for the C—X bond forming step. The intersection of the two cycles, that is transmetallation of the hydrocarbon group from platinum/palladium to copper, is poorly understood while being decisive for the outcome of the reaction. To connect two different catalyticallly active metal fragments, bridging acetate ligands are ideally suited (Gerdes, 2004) and therefore deserve our current attention. The title complex, [(TMEDA)Cu(OAc)₂] (TMEDA = tetramethylethane-1,2-diamine), is a promising building block for the generation of the mixed [(TMEDA)Cu(κ¹-acetate)(µ-acetate)ML_n] complexes.

In the mononuclear title complex, the copper(II) atom is in a distorted, square-planar coordination geometry (Fig. 1, Table 1) and bonded to the bidentate tetramethylethane-1,2-diamine ligand [Cu—N 2.037 (2), 2.047 (2) Å] and to the two acetate anions (Dalai et al., 2002; Margraf et al., 2005). The acetato groups in [(TMEDA)Cu(OAc)₂] are mono-coordinating [Cu—O 1.979 (2), 1.9810 (19) Å] (Devereux et al., 2007), but the second oxygen atom of each ligand shows an additional weak interaction with the copper atom [Cu—O 2.509 (2), 2.531 (2) Å], and could be considered to complete a distorted octahedral geometry (Dalai et al., 2002). A similar situation is observed for the zinc analogue, [(TMEDA)Zn(OAc)₂], which displays more pronounced κ²-coordination of the acetates [Zn—O 2.052 (2), 2.353 (4) Å] (Brown et al., 2002).

The molecules in the crystal are connected via hydrogen bonding. There are four short intermolecular C—H···O contacts with O···H distances between 2.34 and 2.58 Å and C—H···O angles between 160 and 176° (Table 2).

Experimental

General Procedures. ESI-MS measurements were performed on a Finnigan MAT TSQ Quantum triple-quad mass spectrometer equipped with electrospray sources. Elemental analyses were performed by the Microanalytical Laboratory of the Laboratorium für Organische Chemie, ETH Zürich.

The title compound was obtained as follows. To a suspension of copper(II)acetate (1.78 g, 9.78 mmol) in MeOH (40 ml) an equimolar amount of TMEDA (1.48 ml, 9.78 mmol) was added and the reaction mixture was stirred for 18 h at room temperature yielding a deep blue solution. After filtration, the solvent was removed in vacuo yielding analytically pure [(TMEDA)Cu(OAc)₂] (2.64 g, 91%) as a blue powder. Crystallization from THF at room temperature yielded blue plates suitable for X-ray crystallography. M.p. 178 °C (decomp.). MS (ESI, positive ions, DCM) m/z (%): 238 (100) [M - O₂CCH₃]⁺. Elem. anal.: Found C, 40.18; H, 7.15; N, 9.41. Calcd. for C₁₀H₂₂N₂O₄Cu: C, 40.33; H, 7.44; N, 9.41.