Synthesis of Ruthenium(III) Phthalocyanine with Di-axial Bromo Ligands - A Promising Molecular Conductor with Giant Negative Magnetoresistance

The electron transport of Phthalocyanines (Pc) with central metal and di-axial ligands (such as FeIII(Pc)L2; where L = CN, Cl, Br) originates from its intermolecular Pc ?-? orbital overlap while its giant negative magnetoresistance (GNMR) arises from its intramolecular Pc-??(HOMO) and Fe-d (s=1/2) interaction. However, the ?-d interaction tends to localize itinerant electrons resulting in the decrease in the conductivity of the FeIII(Pc)L2 series compared to the non-magnetic CoIII(Pc)L2 where ?-d interaction is absent. More so, the axial ligand field energy of the FeIII(Pc)L2 system is found to have the ability to proportionally modulate the ?-d interaction. In reference thereof, theoretical calculations point that isostructural RuIII(Pc)Br2 would provide the best balance of ?-d orbital energy interplay. That is, RuIII(Pc)Br2 is expected to be a molecule with high electrical conductivity and GNMR which would make it an ideal magnetic molecular conductor. This paper reports on the synthesis of RuIII(Pc)Br2.