Magnetic Properties of Polymers Containing Paramagnetic Metalloporphyrins in Their Main Chain

Abstract

Polymers containing paramagnetic metalloporphyrins in their main chains were prepared by condensation copolymerization of 5,10-bis(ethoxyphenyl)-15,20-bis(hydroxyphenyl)porphyrin (HETPP) with dibromomethane. Paramagnetic metal ions were introduced to porphyrin moieties. This type of polymer is expected to show novel magnetic behavior through both intra- and inter-molecular interactions. PolyHETPP-M (M = Ag^II, Cu^II, Co^II, or V^IVO) contains 5–10 HETPP units and is soluble in many organic solvents. Magnetic properties of polymer and monomer were investigated by measurements of magnetic susceptibilities. In the course of this research, solvent effects on magnetic properties of obtained polymers in reprecipitation of polymer containing vanadyl ion was observed. Magnetic interactions of vanadyl complex of polymer were varied from antiferromagnetic to ferromagnetic by precipitation in methanol. ESR measurements indicated that the origin of the difference was caused from ligation of methanol, which was used as precipitation solvent, to vanadyl ion to prevent stacking of porphyrin moieties. From this result, it is possible that magnetic property of polyHETPP-V^IVO can be controlled by the selection of solvents for purification of polymers.