Laurent Poorters, Dominique Armspach, Dominique Matt, Loïc Toupet, Sylvie Choua and Philippe Turek
Spanning over 50 years of research… Venanzi, Van Leeuwen, Protasiewicz, Gelman, and others have been involved in the design and synthesis of so-called trans-spanning diphosphines (see examples depicted). Chelating ligands of this type have become very useful in homogeneous catalysis. In fact, most of these ligands do not always behave as they are supposed to, namely as trans-binders, their reactions with transition metals frequently leading to cis-complexes and sometimes also to non-chelating structures. In their Full Paper on page 9448 ff., D. Matt, D. Armspach and co-workers describe the ligand TRANSDIP, a cyclodextrin-derived, rigidified diphosphine, which provides trans-chelated complexes exclusively when treated with d8-metal halides. A complex of this type is illustrated on the bottom right of the picture, which also shows the Strasbourg skyline.