Self-assembly, structure, and physical properties of tetranuclear Zn-II and Co-II complexes of [2x2] grid-type

The tretrametallic [2 x 2] grid-type complexes 1-4 are formed by self-assem bly of the bis(tridentate) ligands 5 and 6 with Zn-II and Co-II cations. Th ey have been characterized by spectroscopic studies in solution as well as by crystal structure determination. The substituents in the central pyrimid ine ring play an important role in terms of geometry and physical propertie s of the complexes. They induce an orthogonal orientation of the ligand in the complexes which is critical for the formation of ordered monolayers and extended self-organized arrays of grids. The physical properties of the co mplexes such as metal-metal interaction and pi-pi* slacking between the lig ands may be modulated by changing these substituents.