Atropoisomerism in Phosphepines and Azepines
journal contributionposted on 04.12.2009, 00:00 by Ester Fjellander, Zoltán Szabó, Christina Moberg
Free energy barriers to biaryl tropoinversion in metal complexes with tropos phosphepine and azepine ligands were determined by temperature-dependent 31P NMR inversion-transfer experiments and line shape analysis of the temperature-dependent 1H NMR spectra, respectively. The barrier in the PdCl2 complex of the azepine ligand was found to be slightly higher than that of the corresponding free ligand. Studies of a tridentate azepine ligand suggested that configurational change takes place without prior decoordination from the metal.