A new Fe(6) ferric cluster: synthesis, crystal structure and magnetic properties.

A new Fe(III)(6) cluster, [Fe(3)L(2)(ida)(mu-OH)(3)(mu-O)](2).4ClO(4).2CH(3)OH.8H(2)O (1) (where L = N-methyl-N,N-bis(2-pyridylmethyl)amine; H(2)ida = iminodiacetic acid), has been synthesized and magnetic properties are shown. The asymmetric unit of 1 contains a triangular [Fe(3)L(2)(ida)(mu-OH)(3)(mu-O)](2+) unit and two such trinuclear units are further connected by two ida(2-), generating a hexanuclear Fe(III) core in 1. Variable temperature magnetic susceptibility studies reveal the presence of dominant antiferromagnetic exchange interactions and the variable-field and temperature magnetization measurements establish that each Fe(3) cluster has S = 5/2 ground state and the coupling between the two moieties is almost zero.