STRUCTURES AND MAGNETIC-PROPERTIES OF DINUCLEAR IRON(III) COMPLEXES

The compounds [FeL(1)(MeOH)Cl](2) (1), [FeL(2)Cl](2) (2) and [FeL(3)Cl ](2) (3), with L(1) for N-2-hydroxy-4-chlorophenylsalicylaldimin L(2) for N-2-hydroxyphenyl-3-hydroxy-2-naphthaldimin, and L(3) for -hydroxy -4-chlorophenyl-3-hydroxy-2-naphthaldimin, have been synthesized. 1 cr ystallizes in the monoclinic system, space group P2(1)/c. The lattice parameters are a= 7.347(1), b=21.390(1), c=9.555(2)Angstrom, beta=104. 92(1)degrees with Z=2. The crystal structures of 2 and 3 were reported previously. In all structures, two identical [FeL] fragments, related by an inversion center, are connected by two bridging oxygen atoms to form a binuclear unit in the supported condition. Magnetic susceptibi lity measurements in the range 4.2<T<286.5 K revealed the diiron (III) centers of 1, 2, and 3 to be weakly antiferromagnetically coupled wit h spin exchange coupling constants J(1)=-7.7(1) cm(-1), J(2)=-6.5(1) c m(-1), and J(3)=-10.9(1) cm(-1),respectively.