FULL PAPER DOI: 10.1002/ejic.201200737 Copper(II) Cubane Complexes Built from Electro- and Photosensitive β-Aminovinyl Trifluoromethyl Ketone Ligands Nicolas Chopin,* [a] Guillaume Chastanet, [b] Boris Le Guennic, [c] Maurice Médebielle,* [a] and Guillaume Pilet* [d] Keywords: Copper / Cubane complexes / Magnetic properties / Density functional calculations A new family of [Cu 4 L 4 ] cubane complexes have been syn- thesized by the self-assembly of Cu II salts and β-aminovinyl trifluoromethyl ketone ligands. The resulting polynuclear architectures were especially designed to exhibit magnetic properties arising from the metallic cubane architecture as well as electro- or photosensitive properties arising from the ligands. The optical and electrochemical behaviours of the compounds were measured in solution to confirm that the properties of the free ligands were retained within the elabo- rated complexes. DFT investigations of the organic moieties Introduction Polynuclear architectures have attracted a great deal of attention, especially for their magnetic potentialities brought on by the metallic ions. [1–3] Among them, [M 4 X 4 ] cubane complexes (M = metal ions, X = S, O, for example) have been widely examined because the particular organiza- tion of the paramagnetic ions within these architectures fa- vours ferromagnetic interactions. [4,5] The resulting high-spin ground-state can lead to single-molecule magnet (SMM) behaviour, [6] or such complexes can be used as building blocks to elaborate clusters with higher nuclearity. [7] Among the numerous ligands employed in the synthesis of cubane cores, bidentate β-diketone units and tridentate Schiff base [a] Université Claude Bernard Lyon 1, Institut de Chimie et Biochimie Moléculaire et Supramoléculaire (ICBMS), UMR CNRS-UCBL-INSA 5246, Bât. Curien, 43 boulevard du 11 novembre 1918, 69622 Villeurbanne Cedex, France E-mail: nicolas.chopin@gmail.com maurice.medebielle@univ-lyon1.fr Homepage: http://www.icbms.fr/ [b] Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), CNRS-UPR 9048, 87 avenue du Docteur Schweitzer, 33608 Pessac Cedex, France [c] Institut des Sciences Chimiques de Rennes, UMR 6226 CNRS- Université de Rennes 1, 6226, 35042 Rennes Cedex, France [d] Université Claude Bernard Lyon 1, Laboratoire des multi Matériaux et Interfaces (LMI), UMR CNRS-UCBL 5615, Bât. Chevreul, 43 boulevard du 11 novembre 1918, 69622 Villeurbanne Cedex, France E-mail: guillaume.pilet@univ-lyon1.fr Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/ejic.201200737. © 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Eur. J. Inorg. Chem. 2012, 5058–5070 5058 were conducted with the aim of assigning the observed elec- tronic processes to the different redox steps and absorption bands. The crystal structures of the polynuclear complexes were solved and refined by single-crystal X-ray diffraction analysis and correlated to variable-temperature magnetic susceptibility data. The overall expected ferromagnetic be- haviour of the [Cu 4 L 4 ] complexes is weakly influenced by the ligand substitutions. Ab initio configuration interaction calculations helped us to detail the variations of the various magnetic exchange pathways. ligands derived from the condensation of amines with β- diketones have been used extensively. Our research is cur- rently devoted to the elaboration of ligands able to bring additional properties to the magnetic core with the expecta- tion that both properties could interact cooperatively. To do this we have focused our attention on β-aminovinyl trifluoro- methyl ketones, which are frequently exploited as valuable starting compounds in the preparation of various trifluoro- methylated aromatic and heterocycle molecules. [8] On the other hand, their ability to coordinate a large panel of tran- sition-metal ions have led to the preparation of a number of metallomesogens with interesting liquid-crystal proper- ties [9–12] or highly-active catalysts for olefin polymerization, including fluorinated enaminones. [13–15] β-Aminovinyl ketones with a fluoroalkyl moiety are thus considered to be interesting building blocks that can be decorated in a number of synthetic sequences to produce diverse molecu- lar entities for specifically designed applications. [8,16–26] Their potential for diverse coordination chemistry [27–36] combined with appropriate pendant organic functionalities (a photosensitive unit, a stable radical, an electron donor, a luminescent unit or a biomolecule) make them attractive for the design of new generations of original materials. More- over, these enaminone building blocks offer great potential for rapidly generating molecular diversity (see the general structure in Scheme 1) because these organic substrates can be structurally modified at different sites (R 1 ,R 2 ,R 3 and R 4 ) by variation of 1) the amine (R 1 ), 2) the substitution on the C=C double bond (R 2 and R 3 ) and 3) the fluoroalkyl moiety (R 4 ). [21–23] Organic functionalities with specific properties that we are interested in can in principle be at-