Pentacoordination for pincer and related terdentate coordination compounds: Revisiting structural properties and trends for d8 transition metal systems

Pentacoordinate complexes of d8 transition metals from groups 9 and 10 display trigonal bipyramidal or square pyramidal coordination geometries that are influenced by ligand character (chelation, steric properties, trans-directing ability, etc.) as well as intrinsic preferences of the metal center.50