title: Geometry flexibility of copper iodide clusters: variability in luminescence thermochromism.
abstract: An original copper(I) iodide cluster of novel geometry obtained by using a diphosphine ligand is reported and is formulated [Cu6I6(PPh2(CH2)3PPh2)3] (1). Interestingly, this sort of "eared cubane" cluster based on the [Cu6I6] inorganic core can be viewed as a combination of the two known [Cu4I4] units, namely, the cubane and the open-chair isomeric geometries. The synthesis, structural and photophysical characterisations, as well as theoretical study of this copper iodide along with the derived cubane (3) and open-chair (2) [Cu4I4(PPh3)4] forms, were investigated. A new polymorph of the cubane [Cu4I4(PPh3)4] cluster is indeed presented (3). The structural differences of the clusters were analyzed by solid-state nuclear magnetic resonance spectroscopy. Luminescence properties of the three clusters were studied in detail as a function of the temperature showing reversible luminescence thermochromism for 1 with an intense orange emission at room temperature. This behavior presents different feature compared to the cubane cluster and completely contrasts with the open isomer, which is almost nonemissive at room temperature. Indeed, the thermochromism of 1 differs by a concomitant increase of the two emission bands by lowering the temperature, in contrast to an equilibrium phenomenon for 3. The luminescence properties of 2 are very different by exhibiting only one single band when cooled. To rationalize the different optical properties observed, density functional theory calculations were performed for the three clusters giving straightforward explanation for the different luminescence thermochromism observed, which is attributed to different contributions of the ligands to the molecular orbitals. Comparison of 3 with its [Cu4I4(PPh3)4] cubane polymorphs highlights the sensibility of the emission properties to the cuprophilic interactions.
authors: Quentin
authors: Q
authors: Benito
authors: Xavier F Le
authors: XF
authors: Goff
authors: Gregory
authors: G
authors: Nocton
authors: §Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), CNRS, 87 Avenue du Docteur A. Schweitzer, 33608 Pessac Cedex, France.
authors: Alexandre
authors: A
authors: Fargues
authors: §Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), CNRS, 87 Avenue du Docteur A. Schweitzer, 33608 Pessac Cedex, France.
authors: Alain
authors: A
authors: Garcia
authors: ∥UMR-CNRS, 6226 Institut des Sciences Chimiques de Rennes, Université de Rennes 1, 35042 Rennes Cedex, France.|⊥Université Européenne de Bretagne, 5 bd. Laënnec, 35000 Rennes, France.
authors: Aurélie
authors: A
authors: Berhault
authors: ∥UMR-CNRS, 6226 Institut des Sciences Chimiques de Rennes, Université de Rennes 1, 35042 Rennes Cedex, France.|⊥Université Européenne de Bretagne, 5 bd. Laënnec, 35000 Rennes, France.
authors: Samia
authors: S
authors: Kahlal
authors: ∥UMR-CNRS, 6226 Institut des Sciences Chimiques de Rennes, Université de Rennes 1, 35042 Rennes Cedex, France.|⊥Université Européenne de Bretagne, 5 bd. Laënnec, 35000 Rennes, France.
authors: Jean-Yves
authors: JY
authors: Saillard
authors: #Tectospin, Institut Lavoisier de Versailles (ILV), UMR CNRS 8180, Université de Versailles St-Quentin en Yvelines (UVSQ), 45, avenue des Etats-Unis, 78035 Versailles Cedex, France.
authors: Charlotte
authors: C
authors: Martineau
authors: ⊗Science et Technologies, Université Lille, F-59000 Lille, France.|○NRS UMR 8181, Unité de Catalyse et de Chimie du Solide-UCCS; ENSCL, F-59652 Villeneuve d'Ascq, France.
authors: Julien
authors: J
authors: Trébosc
authors: Thierry
authors: T
authors: Gacoin
authors: Jean-Pierre
authors: JP
authors: Boilot
authors: Sandrine
authors: S
authors: Perruchas
mesh_terms: D003300:Copper / Q000737:chemistry*; D018360:Crystallography, X-Ray; D007454:Iodides / Q000737:chemistry*; D008024:Ligands; D049449:Luminescence; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis*; D010720:Phosphines / Q000737:chemistry*; D011789:Quantum Theory; D013696:Temperature; D013816:Thermodynamics
chemical_list: D007454:Iodides; D008024:Ligands; D009942:Organometallic Compounds; D010720:Phosphines; D003300:Copper