Stepwise Construction of Heterobimetallic Cages by an Extended Molecular Library Approach

Two novel heterobimetallic complexes, trigonal-bipyramidal and a cubic one, have been synthesized and characterized using the same C-3-symmetric metalloligand, prepared by a simple subcomponent self-assembly strategy. Adopting the molecular library approach, we chose a mononuclear; preorganized iron(II) complex as the metalloligand capable of self-assembly into a trigonal-bipyramidal or a cubic aggregate upon coordination to cis-protected C-2-symmetric palladium(II) or unprotected tetravalent palladium-(II) ions, respectively. The trigonal-bipyramidal complex was characterized by NMR and UV-vis spectroscopy, electrospray ionization mass spectrometry (ESI-MS), and single-crystal X-ray diffraction. The cubic structure was characterized by NMR and UV-vis spectroscopy and ESI-MS.