Assembly of π‐Conjugated Phosphole Azahelicene Derivatives into Chiral Coordination Complexes: An Experimental and Theoretical Study |
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Authors: | Sebastien Graule Mark Rudolph Wenting Shen J?A?Gareth Williams Dr Christophe Lescop Dr Jochen Autschbach Prof Jeanne Crassous Dr Régis Réau Prof |
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Institution: | 1. Sciences Chimiques de Rennes, UMR 6226 CNRS, Université de Rennes 1, Campus de Beaulieu, 35042 Rennes Cedex (France), Fax: (+33)?2‐23‐23‐69‐39;2. Department of Chemistry, 312 Natural Sciences Complex, State University of New York at Buffalo, Buffalo, NY 14260‐3000 (USA);3. Department of Chemistry, University of Durham, Durham, DH1?3LE (UK) |
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Abstract: | Azan]helicene phosphole derivatives have been prepared from azan]helicene diynes by the Fagan–Nugent route. Their photophysical properties (UV/Vis absorption and emission behavior) have been evaluated. Their behavior as P,N chelates towards coordination to PdII and CuI has been investigated: metal–bis(azan]helicene phosphole) assemblies are formed by a highly stereoselective coordination process, as demonstrated by X‐ray crystallography. An aza6]helicene phosphole bearing an enantiopure helicene part has been obtained, which allows the preparation of enantiopure PdII and CuI complexes with original topologies and high molar rotation (MR) and circular dichroism (CD). The structure–property relationship established from the experimental data has been studied in detail by theoretical studies (TDDFT calculations of UV/Vis, CD, and MR). Azan]helicene phosphole derivatives show π conjugation extended over the entire molecule, and its influence on the MR of aza6]helicene phosphole 5 c has been demonstrated. Finally, it has been shown that the nature of the metal (coordination geometry and electronic interaction) can have a great impact on the amplitude of the chiroptical properties in metal–bis(azan]helicene phosphole) assemblies. |
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Keywords: | chiroptical properties density functional calculations helical structures palladium P N ligands |
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