Thermochromic luminescence of copper iodide clusters: the case of phosphine ligands. - Université de Rennes Accéder directement au contenu
Article Dans Une Revue Inorganic Chemistry Année : 2011

Thermochromic luminescence of copper iodide clusters: the case of phosphine ligands.

Résumé

Three copper(I) iodide clusters coordinated by different phosphine ligands formulated [Cu(4)I(4)(PPh(3))(4)] (1), [Cu(4)I(4)(Pcpent(3))(4)] (2), and [Cu(4)I(4)(PPh(2)Pr)(4)] (3) (PPh(3) = triphenylphosphine, Pcpent(3) = tricyclopentylphosphine, and PPh(2)Pr = diphenylpropylphosphine) have been synthesized and characterized by (1)H and (31)P NMR, elemental analysis and single crystal X-ray diffraction analysis. They crystallize in different space groups, namely, monoclinic P21/c, cubic Pa3̅, and tetragonal I4̅2m for 1, 2, and 3, respectively. The photoluminescence properties of clusters 1 and 3 show reversible luminescence thermochromism with two highly intense emission bands whose intensities are temperature dependent. In accordance to Density Functional Theory (DFT) calculations, these two emission bands have been attributed to two different transitions, a cluster centered (CC) one and a mixed XMCT/XLCT one. Cluster 2 does not exhibit luminescence variation in temperature because of the lack of the latter transition. The absorption spectra of the three clusters have been also rationalized by time dependent DFT (TDDFT) calculations. A simplified model is suggested to represent the luminescence thermochromism attributed to the two different excited states in thermal equilibrium. In contrast with the pyridine derivatives, similar excitation profiles and low activation energy for these phosphine-based clusters reflect high coupling of the two emissive states. The effect of the Cu-Cu interactions on the emission properties of these clusters is also discussed. Especially, cluster 3 with long Cu-Cu contacts exhibits a controlled thermochromic luminescence which is to our knowledge, unknown for this family of copper iodide clusters. These phosphine-based clusters appear particularly interesting for the synthesis of original emissive materials.

Domaines

Matériaux
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Dates et versions

hal-00646861 , version 1 (30-11-2011)

Identifiants

Citer

Sandrine Perruchas, Cédric Tard, X. F Le Goff, Alexandre Fargues, Alain Garcia, et al.. Thermochromic luminescence of copper iodide clusters: the case of phosphine ligands.. Inorganic Chemistry, 2011, 50 (21), pp.10682-10692. ⟨10.1021/ic201128a⟩. ⟨hal-00646861⟩
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