Self-assembled Transition Metal Coordination Frameworks of ...

Chapter I W 7 _ W _ 7 pg _ jg to
process offers a valuable means of preparing, in an often rational and highly selective
manner, coordination compounds whose structural complexity starts to approach that
common in biology. As in biology, such compounds may exhibit novel physical and
chemical properties with interesting and useful associated applications. The greatest
importance of coordination chemistry in the future will almost certainly be in bringing
higher levels of molecular organization into the design of molecules and complicated
molecular systems [5].
The primary objective and key step in present study is the design of suitable
ditopic ligands with the anticipation of using them as building blocks for transition
metal coordination frameworks, mainly molecular square grid complexes. However,
the work involves other coordination frameworks like mononuclear, dinuclear,
trinuclear and tetranuclear complexes of these ligands also. The reason behind the
anticipation and selection of molecular squares is their increasing attention in the
current period of coordination chemistry. Metallosupramolecular squares are one of
the simplest but nonetheless interesting members of the family of polygons. They
have now been considered as versatile substitutes of the conventional organic
macrocycles [13]. The synthesis and characterization of molecular squares have
achieved growing interest during the last decade especially because of their wide
spectrum of applications in science and technology. The first step towards this
direction was explored by Fujita et al. [14] by making use of the cis-protected square
planar Pd" and linear bidentate ligand 4,4’-bipyridine. The initial purpose for the
construction of molecular squares was to utilize them as artificial receptors [13].
Self-assembly and kinetically controlled macrocyclization are major strategies
for the construction of such architectures. Of these, self-assembly is a powerful and
simple approach to build up interesting multidimensional frameworks often having
versatile magnetic properties and endowed with special functional properties. A more
important aspect in this area is that the self-assembled complexes may exhibit new
and unexpected properties particularly owing to the binding abilities of the receptor
4