Title
Synthesis and Structural Properties of Aza[n]helicene Platinum Complexes: Control of Cis and Trans Stereochemistry
Author
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
Year
2016
Journal
Inorganic Chemistry
Abstract
The synthesis and structural characterization of azahelicene platinum complexes obtained fromcis-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.
Instrument
J-815
Keywords
Circular dichroism, Stereochemistry, Coordination chemistry, Inorganic chemistry