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

Abstract

The electron transport of Phthalocyanines (Pc) with central metal and di-axial ligands (such as Fe III (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 Fed (s=1/2) interaction. However, the -d interaction tends to localize itinerant electrons resulting in the decrease in the conductivity of the Fe III (Pc)L2 series compared to the non-magnetic Co III (Pc)L2 where -d interaction is absent. More so, the axial ligand field energy of the Fe III (Pc)L2 system is found to have the ability to proportionally modulate the -d interaction. In reference thereof, theoretical calculations point that isostructural Ru III (Pc)Br2 would provide the best balance of -d orbital energy interplay. That is, Ru III (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 Ru III (Pc)Br2.

Synthesis of Highly Soluble Axially-Ligated Ruthenium(III) Phthalocyanine Salt: Potassium Dithiocyanato(phthalocyaninato)ruthenium(III)

“…Ru II (Pc) is synthesized from RuCl 3 •nH 2 O and 2-cyanobenzamide, while Ru III (Pc -)Br 2 was derived from the reaction of Ru II (Pc -2 ) and Thionyl bromide, based on previously reported procedures 9,10 .…”