Pentanuclear cyanide-bridged complexes with high spin ground states S=6 and 9: Characterization and magnetic properties

Two pentanuclear complexes are obtained from the reaction of hexacyanochrom ate(III) with one to two molar equivalents of [Ni(H2O)(6)](2+) and bidentat e organic ligands that chelate the metal ion, leaving two coordination site s in cis positions, Even though the crystal structure was not solved, the f ull characterization supports the formation of pentanuclear discrete specie s. [Cr(CN)(6)](2)[Ni(HIM2-py)(2)](3). 7H(2)O, 1, has a ground spin state S= 6 owing to the ferromagnetic interaction between Cr-III (S = 3/2) and N-II (S = 1), The presence of six organic radicals that couple ferromagnetically with Ni-II in [Cr(CN)(6)](2)[Ni(IM2-PY)(2)](3). 7H(2)O, 2, leads to an S= 9 ground state. A.c. susceptibility measurements below 2K indicate the occu rrence of an antiferromagnetic order at 1.5 K in 2. (C) 2001 Academic Press .