MAGNETIC-PROPERTIES OF SOME TRIANGULAR TRINUCLEAR COMPLEXES OF [RU(2)M(MU-CH3COO)(6)(MU(3)-O)(PY)(3)](N+) WITH A DIAMAGNETIC ION M

The magnetic susceptibilities and the electron paramagnetic resonances (EPRs) of four complexes: [Ru(2)M(mu-CH3COO)(6)(mu(3)-O)(py)(3)](n+) (M=Zn(II), Mg(II), and Ru(II): n=0; and Rh(III): n=1) salts were observed. These are magnetic dimers of Ru(III). The results were analysed under the assumptions that the strong antiferromagnetic superexchange interaction (J(3)) is working through mu(3)-O bridge and that the antiferromagnetic superexchange interaction (J(1)) through mu-(CH3COO)(2)-M(dia)-(CH3COO)(2) is very weak compared to those of double mu-acetato bridges (J(2)'s) and of the mu(3)-O bridge between Ru(III) ions considering the Goodenough-Kanamori rule. The fitting assuming a probability for each path showed the antiferromagnetic interactions through mu 3-O were much stronger than that of the symmetric trimer M=Ru(III). J(1)/k's were -1.4--6.5 K (J(1); -97--450 m(-1)), J(2)/k's were -40--110 K (J(2); -2780--7640 m(-1)), and J(3)/k's were -500--900 K (J(3); -34700--62500 m(-1)). Samples of M=Rh(III) and Ru(II) seem to show weak ferromagnetism.