Evidence for existence of high-spin cluster systems in polymeric dithiolenes

Abstract

Summary form only given. We report on measurements of the ac-susceptibility X/sub ac/ and ESR on the polymeric transition metal (Fe, Mn, and Pd) dithiolene complexes. The ac-magnetization M was extracted from the X/sub ac/ -data at constant temperatures and in a varying external static magnetic field H, using the relation M=/spl mu//sub o/X/sub ac/H . The onset of saturation effects is found to be in H /spl sim/ 2 kG, being much lower than that of a single monomer. This will be explained by the existence of magnetic clusters of up to 2000 monomers, having the effective spin S/sub eff/ > 30 and correspondingly the effective magnetic moments per monomer /spl mu//sub eff/ > 30 /spl mu//sub B/ ! (Similar cluster effects were also observed (see Ref. [1]) in an anilin polymeric system with much lower S/sub eff/ = 1.68 ) The deduced values of /spl mu//sub eff/ are much lower than the sum of magnetic moments of the metallic ions (e.g. for Mn++ /spl mu//sub eff/ = 5.9 /spl mu//sub B/) in a cluster. This means that the cluster system is of speromagnetic character. The susceptibility evaluated from the ESR lines is much lower (factor of < 0.01) than X/sub ac/. Thus the system is very sluggish to respond to the high frequency of the ESR.