Topological and Steric Constraints to Stabilize Heteroleptic Copper(I) Complexes Combining Phenanthroline Ligands and Phosphines |
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Authors: | Dr Michel Holler Dr Béatrice Delavaux-Nicot Dr Jean-François Nierengarten |
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Institution: | 1. Laboratoire de Chimie des Matériaux Moléculaires, Université de Strasbourg et CNRS (LIMA-UMR 7042), École Européenne de Chimie, Polymères et Matériaux (ECPM), 25 rue Becquerel, 67087 Strasbourg Cedex 2, France;2. Laboratoire de Chimie de Coordination du CNRS (UPR 8241), Université de Toulouse (UPS, INPT), 205 Route de Narbonne, 31077 Toulouse Cedex 04, France |
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Abstract: | Heteroleptic copper(I) complexes combining phenanthroline derivatives (NN) and chelating bisphosphine ligands (PP) are an important class of luminescent materials for various applications. Although thermodynamically stable, Cu(NN)(PP)]+ derivatives are also kinetically unstable. As a result, a dynamic ligand-exchange reaction is often observed in solution, leading to a dynamic mixture of heteroleptic and homoleptic complexes. To prevent the formation of the homoleptic species, macrocyclic phenanthroline ligands have been used for the preparation of Cu(NN)(PP)]+ pseudorotaxanes. The topological constraint resulting from the macrocyclic structure of the NN ligand drives the thermodynamic equilibrium towards the exclusive formation of the heteroleptic complex as long as the macrocycle is large and flexible enough to allow for the threading of the PP ligand. Conversely, when the threading is prevented by steric constraints, unprecedented copper(I) complexes with a trigonal coordination geometry are obtained. These results are summarized in the present concept article. |
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Keywords: | bisphosphine ligands copper macrocycles phenanthroline ligands pseudorotaxanes |
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