Edge-bridged tetrahedral geometry of five-coordinate d(0) complexes, relatives of the bent [MCp2L3] family: A theoretical and structure-correlation study

The edge-bridged tetrahedral geometry of five-coordinate d(0) complexes [MD2L3] with strong pi-donors D is analyzed with extended Huckel methodology as well as density functional theory. It is shown that this geometry, also encountered in bent metallocene systems [MCp2L3], can be considered as a distortion of a regular trigonal bipyramid arising from a second-order Jahn-Teller distortion of e' symmetry (in D-3h) and corresponds to a deformation along a reversed-Ferry pathway. This model was tested with a structure-correlation analysis of all experimentally determined [MD2L3] structures, thus allowing a mapping of the reversed-Berry pathway. The catalytic potential of these complexes and their isolobal relationship to [MCp2L3] are emphasized.