Magnetic properties of hetero polymetallic systems

Summary form only given. In a past few years, extensive works to design and synthesize hetero polymetallic systems which, exhibit ferromagnetic properties have been carried out. Our approach to achieve molecular ferromagnet has been to impose ferromagnetic super exchange interactions between nearest neighbor hereto metal centers in alternating arrayed manner. In this study, hereto poly metal tetrathiolates (poly (M/sub 1/TM/sub 2/), T:tetrathiolate) have been synthesized. Those complexes were obtained by synthesizing M/sub 1/T ions, which act as a ligand to M/sub 2/ ions to form alternating ordered hetero polymetaflic systems. In order to elucidate magnetic properties of the compounds, measurements of the magnetic susceptibilities and spin states of metal centers were performed. It was found that some of the M/sub 1/M/sub 2/ alternating ordered hetero polymetallic chains, where M/sub 1/=Fe(III), M/sub 2/=Cu(II), Ni(II), exhibit one-dimensional ferromagnetic-like behaviors in the low temperatures, that are resulting from ferromagnetic intrachain interactions. Upon cooling to further low temperature magnetic susceptibility sharply decreases. The interpretation of the behavior in this range is most likely due to an interchain antiferromagnetic interaction. The computer simulations of the magnetic susceptibilities were also performed on the basis of two parameter Heisenberg models, and the calculated results were in consistent with the observations.