Regioselective functionalization of tetrabromophenanthroline-ruthenium complexes

Structural, photophysical and -chemical characterisation and reactivity of a novel polypyridyl ruthenium complex based on 3,5,6,8-tetra-bromophenanthroline are discussed. Signal storage at a molecular level is great challenge for chemistry.1 The possibility of connecting different functionalities selectively to one ligand of a metal complex may open the route towards higher integrated molecular units capable of processing various external stimuli in a predesignated order. The implementation of this concept demands ligands with a multitude of potential connecting groups which can selectively be transformed.2 3-bromo- and 3,8-dibromophenanthrolines have proved useful for the preparation of mononuclear3 and multiheteronuclear complexes.4 These systems have found applications ranging from DNA photoprobes5 to metalloligands in catalysis.6 A very useful feature of this bromophenanthroline ruthenium complexes is their susceptibility towards nucleophilic aromatic substitution which is very well established