Everyone knows that like charges repel one another. But unusual coordination compounds bearing cationic ligands bound to cationic metals have been prepared by scientists in Israel, opening up fresh opportunities for organic transformations.
Gandelman's team have successfully made rhodium (pictured) and platinum forms of the unusual complexes
When two positively charged chemical species are brought together they experience counteracting forces. One is Coulombic repulsion, and the other is attraction due to the bonding interactions between the nuclei of one cation and the electrons of the other. Thermodynamically unstable bonds ensue from the interplay of these opposing interactions.
Rather than being thermodynamically stable, the transition metal complexes made by Mark Gandelman from the Israel Institute of Technology in Haifa and colleagues manage to be kinetically stable. Pincer-type ligands with nitrenium moieties at their centre, that are essentially the nitrogen analogues of N-heterocyclic carbenes, are central to the complexes’ creation. Computational investigations reveal that the coordination geometry of the pincer ligand provides the kinetic barrier to dissociation of the nitrogen–metal bond; the two phosphine arms aid coordination by bringing the metal within close proximity of the central nitrogen.
Read the full article in Chemistry World»
Read the original journal article in Chemical Science:
Cation-Cation Bonding in Nitrenium Metal Complexes
Mark Gandelman, Yuri Tulchinsky, Prasenjit Saha, Sebastian Kozuch, Mark M Botoshansky and Linda Shimon
Chem. Sci., 2013, Accepted Manuscript, DOI: 10.1039/C3SC53083C, Edge Article
