Hybrid-density functional study of magnetism and ligand control in Ni9 complexes

Strong influences of bridging ligands L on the magnetism of two Ni9 complexes, Ni9L2(O2CMe)8 {(2-py)2CO2}4 (L=OH−1 and N3-2) are demonstrated by magnetic interactions. Effective exchange integrals J for 1 and 2 are determined non-empirically using UB3LYP and UBLYP. The calculated magnetic susceptibility for 1 is wholly consistent with the experimental values. Although the ground spin state of 2 obtained using the calculated J values agrees with the experimental S = 9 state, fitting of the J values to the experimental magnetic susceptibility curve indicates weak antiferromagnetic interactions via the azido ligands.