Synthesis and Structural Properties of Aza[n]helicene Platinum Complexes: Control of Cis and Trans Stereochemistry

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• 作者：Daniele Mendola ; Nidal Saleh ; Nora Hellou ; Nicolas Vanthuyne ; Christian Roussel ; Loïc Toupet ; Franca Castiglione ; Federica Melone ; Tullio Caronna ; Francesca Fontana ; Javier Martı́-Rujas ; Emilio Parisini ; Luciana Malpezzi ; Andrea Mele ; Jeanne Crassous
• 刊名：Inorganic Chemistry
• 出版年：2016
• 出版时间：March 7, 2016
• 年：2016
• 卷：55
• 期：5
• 页码：2009-2017
• 全文大小：591K
• ISSN：1520-510X

文摘

The synthesis and structural characterization of azahelicene platinum complexes obtained from cis-PtCl₂(NCEt)(PPh₃) and from ligands that differ in terms of both the position of the nitrogen atom and the number of fused rings are reported. These square-planar complexes of the general formula PtCl₂(nHm)(PPh₃) (n = 4, 5; m = 5, 6) display mainly a cis configuration. However, by X-ray crystallographic analysis, we show that for both PtCl₂(4H6)(PPh₃) and PtCl₂(5H6)(PPh₃) there is chirality control of the cis/trans stereochemistry. Indeed, starting from a racemic mixture of aza[6]helicene, platinum complexes with a cis configuration are invariably obtained, and the more thermodynamically stable trans isomers are formed when using enantiopure ligands. We further corroborated these results by NMR analysis in solution.