Coordination assemblies from a Pd(II)-cornered square complex.

The [enPd(II)]2+ (en = ethylenediamine) unit has emerged as a versatile building block in molecular self-assembly. In particular, the 90 degrees coordination angle of the metal has been judiciously used in the design of new discrete two- and three-dimensional structures. Our last 15 years of work with the Pd(II)-cornered unit is summarized in this Account, from the spontaneous formation of a Pd4 square metal complex to a family of architectures such as cages, bowls, boxes, tubes, catenanes, and spheres.